These are organizations that span that gray area between civilian law enforcement and the military. Much like the US Coast Guard. The Coast Guard is not a purely military force like the Navy, nor is it a civilian law enforcement agency like a transportation police. It performs some customs and security duties, but also does search and rescue functions plus environmental protection.

Arguably the proper term is "quasi-military".

According to

  • QUASI-MILITARY: Groups who pretend they're connected with the military
  • PARA-MILITARY: Really dangerous groups who aren't part of the military but kill people anyway

Note that all of this has only addressed the origins of space forces from scratch on colonies.  There are two other potential sources for space forces, existing Air Forces and the law-enforcement organization that will inevitably spring up to police human space presence (see Section 11).  This organization will be called the ‘Space Guard’ as it will likely be broadly analogous to the modern-day US Coast Guard.  The Air Force solution is somewhat unlikely, as it requires there to be a reason for current Air Forces to move into orbit in a major way, and the author cannot come up with a plausible explanation for this, even as an extension of their current responsibility for space operations.  The Space Guard would be unlikely to grow out of the Air Force, as it would initially be something more like transport police, and by the time actual military operations begin to occur, it would be the obvious candidate to become the Space Force.

This could have a major impact on the structure of Space Force.  In most sci-fi, there is a tendency to model Space Forces on Navies, although in reality, this is unlikely.  Even though it might bear more resemblance to a modern Navy than a modern Air Force, the Space Force will have evolved from whatever origin it had.  Either the force would have to have been split off from an actual wet Navy at the beginning (unlikely, as the Air Force would normally be given responsibility for the task) or it would have to consciously choose a naval model for itself.  There are two reasons why the later might occur.  If the space force is being created from scratch, it is possible that those responsible, likely influenced by sci-fi, will choose a naval model.  The alternative is that if the split between the Air and Space forces is acrimonious enough, the new Space Force might choose a naval model to distinguish itself from the Air Force.

The structure of a Space Guard-derived Space Force is much less predictable.  While they will likely evolve into something recognizably military, it is difficult to see what path they will take.  To use the US of today as an example, there are several different agencies (Department of Transportation/FAA, NASA, Department of Justice, Department of the Treasury) which might give birth to the Space Guard.  The use of police ranks is not unlikely, although they might transition to a more traditional military structure as they move into that role.

by Byron Coffey (2016)

Ship's Papers

In the more bureaucratically organized regions of the galaxy, it will be illegal to operate a spacecraft unless you have valid certifications and registrations issued by the government of that region. Much in the same way that passenger aircraft are not allowed to land in country Alfa unless they have certification papers proving that their maintenance schedule is up to date, safety inspections spotted no dangerous cracks in the structural members, and otherwise reassure the bureaucracy of that country that the plane isn't going to explode or unexpectedly plummet out of the sky. And registration papers proving the ship has the required liability insurance, flag of convenience, and isn't reported as stolen.

There will no doubt be other required pieces of paperwork, but those two are the big ones. This is why tramp starships tend to stick to the frontier sections of the galaxy.

Things will get really annoying for starship owners if they need separate papers for each solar system they operate in. Or for each planet they want to orbit or land on.


      "As for the list of ships you gave me, yes. One of them puts in to this planet regularly; she spaced out from here only yesterday morning. The Honest Horris."

     "Well, great Satan, haven't you done anything?"

     "I don't know if there's anything we can do. Oh, we're investigating, but.... You see, this ship first showed up here four years ago, commanded by some kind of a Neobarb, not a Gilgamesher, named Horris Sasstroff. He claimed to be from Skathi; the locals there have a few ships, the Space Vikings had a base on Skathi about a hundred or so years ago. Naturally, the ship had no papers. Tramp trading among the Neobarbs, it might be years before you'd put in on a planet where they'd ever heard of ship's papers.

     "The ship seems to have been in bad shape, probably abandoned on Skathi as junk a century ago and tinkered up by the locals. She was in here twice, according to the commercial shipping records, and the second time she was in too bad shape to be moved out, and Sasstroff couldn't pay to have her rebuilt, so she was libeled for spaceport charges and sold. Some one-lung trading company bought her and fixed her up a little; they went bankrupt in a year or so, and she was bought by another small company, Startraders, Ltd., and they've been using her on a milk-run to and from Gimli. They seem to be a legitimate outfit, but we're looking into them. We're looking for Sasstroff, too, but we haven't been able to find him."

     "If you have a ship out Gimli way, you might find out if anybody there knows anything about her. You may discover that she hasn't been going there at all."

From SPACE VIKING by H. Beam Piper (1962)

Spacecraft Certification

If a spacecraft is flying far away from anything else, and only has weak rockets fueled by puny chemical fuels or innocuous solar panels, nobody cares if the ship is a hunk-of-junk suffering from decades of deferred maintenance. If it blows up, that's too bad about the people on board, but it's their problem.

Things change radically in the more civilized areas of space. In the crowded orbital space around a heavily populated planet, with dozens of space stations, zillions of expensive satellites, hundreds of other spacecraft in tight traffic lanes, and ship using antimatter fuel; the authorities will demand that all spacecraft be up to code with perfect maintenance records.

This means periodic inspections by the Spacecraft Agency, in order for the ships to keep their certification current. No certification means the ship ain't allowed in our orbital space.

For example, in the US, this is the responsibility of the Federal Aviation Administration's Aviation Safety Inspectors. They inspect aircraft and related equipment for airworthiness. They are a Designated Airworthiness Representative (DAR), appointed in accordance with 14 CFR 183.33 who may perform examination, inspection, and testing services necessary to the issuance of certificates. There are two types of DARs: manufacturing, and maintenance. The maintenance type are the ones inspecting aircraft.

The manufacturing type inspect the aircraft before it is even made. Aircraft require a type certificate to signify the airworthiness of an aircraft manufacturing design. This means it is almost impossible to certify an aircraft built from blueprints that lack a type certificate. Or built from no blueprints at all.


"Pegasus to Acheron. How do you suggest we can assist you?" It was eerie to be speaking to a man who was already as good as dead. The traditions of space were as strict as those of the sea. Five men could leave the Acheron alive, but her captain would not be among them.

Halstead did not know that Commodore Brennan had other ideas, and had by no means abandoned hope, desperate though the situation on board the Acheron seemed. His chief medical officer, who had proposed the plan, was already explaining it to the crew.

"This is what we're going to do," said the small, dark man who a few months ago had been one of the best surgeons on Venus. "We can't get at the airlocks, because there's vacuum all round us and we've only got five suits. This ship was built for fighting, not for carrying passengers, and I'm afraid her designers had other matters to think about besides Standard Spaceworthiness Regs. Here we are, and we have to make the best of it.

(ed note: details here)

From EARTHLIGHT by Sir Arthur C. Clarke (1955)

(ed note: Arcot and Morey have invented a handwavium reactionless thruster. They use it to make a prototype revolutionary aircraft. But before they can use it the craft will have to be certified.)

      “Dick,” said Morey as he strode up to him after testing the last of the gyroscopic seats, “she's ready! I certainly want to get her going—it's only three-thirty, and we can go around to the sunlight part of the world when it gets dark at the speeds we can travel. Let's test her now!”
     “I'm just as anxious to start as you are, Bob. I've sent for a U.S. Air Inspector. As soon as he comes we can start. I'll have to put an 'X' license indication on her now. He'll go with us to test it—I hope. There will be room for three other people aboard, and I think you and Dad and I will be the logical passengers.”
     He pointed excitedly. “Look, there's a government helicopter coming. Tell the men to get the blocks from under her and tow her out. Two power trucks should do it. Get her at least ten feet beyond the end of the hangar. We'll start straight up, and climb to at least a five mile height, where we can make mistakes safely. While you're tending to that, I'll see if I can induce the Air Inspector to take a trip with us.
     Half an hour later the machine had been rolled entirely out of the shed, on the new concrete runway.
     The great craft was a thing of beauty shimmering in the bright sunlight The four men who were to ride in it on its maiden voyage stood off to one side gazing at the great gleaming metal hull. The long sweeping lines of the sides told a story of perfect streamlining, and implied high speed, even at rest. The bright, slightly iridescent steel hull shone in silvery contrast to the gleaming copper of the power units' heat-absorption fins. The great clear windows in the nose and the low, streamlined air intake for the generator seemed only to accentuate the graceful lines of the machine.
     “Lord, she's a beauty, isn't she, Dick!” exclaimed Morey, a broad smile of pleasure on his face.
     “Well, she did shape up nicely on paper, too, didn't she. Oh, Fuller, congratulations on your masterpiece. It's even better looking than we thought, now the copper has added color to it. Doesn't she look fast? I wish we didn't need physicists so badly on this trip, so you could go on the first ride with us.”
     “Oh, that's all right, Dick, I know the number of instruments in there, and I realize they will mean a lot of work this trip. I wish you all luck. The honor of having designed the first ship like that, the first heavier-than-air ship that ever flew without wings, jets, or props—that is something to remember. And I think it's one of the most beautiful that ever flew, too.”
     “Well, Dick,” said his father quietly, “let's get under way. It should fly—but we don't really know that it will!”
     The four men entered the ship and strapped themselves in the gyroscopic seats. One by one they reported ready.
     “Captain Mason,” Arcot explained to the Air Inspector, “these seats may seem to be a bit more active than one generally expects a seat to be, but in this experimental machine, I have provided all the safety devices I could think of. The ship itself won't fall, of that I am sure, but the power is so great it might well prove fatal to us if we are not in a position to resist the forces. You know all too well the effect of sharp turns at high speed and the results of the centrifugal force. This machine can develop such tremendous power that I have to make provision for it.
     “You notice that my controls and the instruments are mounted on the arm of the chair really; that permits me to maintain complete control of the ship at all times, and still permits my chair to remain perpendicular to the forces. The gyroscopes in the base here cause the entire chair to remain stable if the ship rolls, but the chair can continue to revolve about this bearing here so that we will not be forced out of our seats. I'm confident that you'll find the machine safe enough for a license. Shall we start?”
     “All right, Dr. Arcot,” replied the Air Inspector. “If you and your father are willing to try it, I am.”
     “Ready, Engineer?” asked Arcot.
     “Ready, Pilot!” replied Morey.
     “All right—just keep your eye on the meters, Dad, as I turn on the system. If the instruments back there don't take care of everything, and you see one flash over the red mark—yank open the main circuit. I'll call out what to watch as I turn them on.”
     “Ready son.”
     “Main gyroscopes!” There was a low snap, a clicking of relays in the rear compartment, and then a low hum that quickly ran up the scale. “Main generators!” Again the clicking switch, and the relays thudding into action, again the rising hum. “Seat-gyroscopes.” The low click was succeeded by a quick shrilling sound that rose in moments above the range of hearing as the separate seat-gyroscopes took up their work. “Main power tube bank!” The low hum of the generator changed to a momentary roar as the relays threw on full load. In a moment the automatic controls had brought it up to speed.
     “Everything is working perfectly so far. Are we ready to start now, son?”
     “Main vertical power units!” The great ship trembled throughout its length as the lift of the power units started. A special instrument had been set up on the floor beside Arcot, that he might be able to judge the lift of his power units; it registered the apparent weight of the ship. It had read two hundred tons. Now all eyes were fixed on it, as the pointer dropped quickly to 150-100-75-50-40-20-10—there was a click and the instrument flopped back to 300—it was registering in pounds now! Then the needle moved to zero, and the mighty structure floated into the air, slowly moving down the field as a breeze carried it along the ground
.     The men outside saw it rise swiftly into the sky, straight toward the blue vault of heaven. In two or three minutes it was disappearing. The glistening ship shrank to a tiny point of light; then it was gone! It must have been rising at fully three hundred miles an hour!
     To the men in the car there had been a tremendous increase in weight that had forced them into the air cushions like leaden masses. Then the ground fell away with a speed that made them look in amazement. The house, the construction shed, the lake, all seemed contracting beneath them. So quickly were they rising that they had not time to adjust their mental attitude. To them all the world seemed shrinking about them.
     Now they were at a tremendous height; over twenty miles they had risen into the atmosphere; the air about them was so thin that the sky seemed black, the stars blazed out in cold, unwinking glory, while the great fires of the sun seemed reaching out into space like mighty arms seeking to draw back to the parent body the masses of the wheeling planets. About it, in far flung streamers of cold fire shone the mighty zodiacal light, an Aurora on a titanic scale. For a moment they hung there, while they made readings of the meters.
     Arcot was the first to speak and there was awe in his voice. “I never began to let out the power of this thing! What a ship! When these are made commercially, we'll have to use about one horsepower generators in them, or people will kill themselves trying to see how fast they can go.”
     Methodically the machine was tried out at this height, testing various settings of the instruments. It was definitely proven that the values that Arcot and Morey had assigned from purely theoretical calculations were correct to within one-tenth of one percent. The power absorbed by the machine they knew and had calculated, but the terrific power of the driving units was far beyond their expectations.
     “Well, now we're off for some horizontal maneuvers,” Arcot announced. “I'm sure we agree the machine can climb and can hold itself in the air. The air pressure controls seem to be working perfectly. Now we'll test her speed.”
     Suddenly the seats swung beneath them; then as the ship shot forward with ever greater speed, ever greater acceleration, it seemed that it turned and headed upward, although they knew that the main stabilizing gyroscopes were holding it level. In a moment the ship was headed out over the Atlantic at a speed no rifle bullet had ever known. The radio speedometer needle pushed farther and farther over as the speed increased to unheard of values. Before they left the North American shoreline they were traveling faster than a mile a second. They were in the middle of the Atlantic before Arcot gradually shut off the acceleration, letting the seats drop back into position.
     A hubbub of excited comments rose from the four men. Momentarily, with the full realization of the historical importance of this flight, no one paid any attention to anyone else. Finally a question of the Air Inspector reached Arcot's ears.
     “What speed did we attain, Dr. Arcot? Look—there's the coast of Europe! How fast are we going now?”
     “We were traveling at the rate of three miles a second at the peak.” Arcot answered. “Now it has fallen to two and a half.”
     Again Arcot turned his attention to his controls. “I'm going to try to see what the ultimate ceiling of this machine is. It must have a ceiling, since it depends on the operation of the generator to operate the power-units. This, in turn, depends on the heat of the air, helped somewhat by the sun's rays. Up we go!”
     The ship was put into a vertical climb, and steadily the great machine rose. Soon, however, the generator began to slow down. The readings of the instruments were dropping rapidly. The temperature of the exceedingly tenuous air outside was so close to absolute zero that it provided very little energy.
     “Get up some forward speed,” Morey suggested, “so that you'll have the aid of the air scoop to force the air in faster.”
     “Right, Morey.” Arcot slowly applied the power to the forward propulsion units. As they took hold, the ship began to move forward. The increase in power was apparent at once. The machine started rising again. But at last, at a height of fifty-one miles, her ceiling had been reached.
     The cold of the cabin became unbearable, for every kilowatt of power that the generator could get from the air outside was needed to run the power units. The air, too, became foul and heavy, for the pumps could not replace it with a fresh supply from the near-vacuum outside. Oxygen tanks had not been carried on this trip. As the power of the generator was being used to warm the cabin once more, they began to fall. Though the machine was held stable by the gyroscopes, she was dropping freely; but they had fifty miles to fall, and as the resistance of the denser air mounted, they could begin to feel the sense of weight return.
     “You've passed, but for the maneuvers, Dr. Arcot!” The Air Inspector was decidedly impressed. “The required altitude was passed so long ago—why we are still some miles above it, I guess! How fast are we falling?”
     “I can't tell unless I point the nose of the ship down, for the apparatus works only in the direction in which the ship is pointed. Hold on, everyone, I am going to start using some power to stop us.”
     It was night when they returned to the little field in Vermont. They had established a new record in every form of aeronautical achievement except endurance! The altitude record, the speed record, the speed of climb, the acceleration record—all that Arcot could think of had been passed. Now the ship was coming to dock for the night. In the morning it would be out again. But now Arcot was sufficiently expert with the controls to maneuver the ship safely on the ground. They finally solved the wind difficulty by decreasing the weight of the ship to about fifty pounds, thus enabling the three men to carry it into the hangar!

From PIRACY PREFERRED by John W. Campbell, Jr. (1930)

America’s national spacefaring enterprise is changing at a pace that has not been seen since the 1960s when space was first accessed on a routine basis. The president’s plans for a US Space Force, others calling for a US Space Guard, a renewed focus on reusability in space launch and on American human space exploration and commercial human spaceflight, and Congressional interest in space-based ballistic missile and satellite defense, are all putting America’s spacefaring future in the public spotlight.

America will not effectively become a true human spacefaring nation without the ability to achieve “aircraft-like access to space.” In this article, I focus on what “aircraft-like access to space” means and why achieving airworthiness certification for commercial passenger spaceflight is necessary to enable aircraft-like access to space to be safely and ethically achieved. (A US Space Force and a US Space Guard will need a comparable capability for any crewed operations they might conduct in space.)

Understanding what “aircraft-like access to space” means

As you read this on a typical morning or afternoon, thousands of commercial airliners, carrying around a half-million people, cruise America’s skies in comfort and safety, as illustrated above. Air travel’s convenience makes it the preferred means for most business and leisure travel. This past July 4th holiday, more than three million Americans traveled by air. We are now 60 years into the jet age of commercial air travel and this industry’s safety and convenience define what “aircraft-like” means to the public.

In the mid-1960s, during the first decade of the human space age, director Stanley Kubrick set out to forecast what our spacefaring civilization would be doing 30 years in the future, in 2001. America’s human spaceflight program was then just beginning two-person missions with the Gemini program. Author Adam K. Johnson superbly records, in 2001: The Lost Science, the technical and industrial expertise Kubrick harnessed in preparing the movie. Kubrick’s depiction of the two-stage-to-orbit Orion III passenger shuttle established our expectations of what “aircraft-like access to space” should be like. While some see the traditional aircraft-like appearance of the Orion III to be what “aircraft-like access to space” means, aerospace engineers understand that the key attribute—as depicted by Dr. Heywood Floyd sleeping in the passenger compartment of the Orion shuttle—was flight safety or airworthiness.

For leisure air travel, Americans routinely take their children while older children often travel by air unaccompanied. Especially with the safety of our children being paramount, the public has high expectations for the safety of air travel. If we are to normalize human space travel, then it must also be made acceptably safe so that working adults—many who have families—will be able to travel to, from, and within space with safety comparable to air travel.

For aircraft, acceptable safety is achieved through airworthiness certification. Comparable airworthiness certification will be needed for human spaceflight systems to achieve “aircraft-like access to space.” Whether the actual space flight system has wings, takes off from a runway, or launches vertically from a pad is not relevant to achieving “aircraft-like” access to space. How it is accomplished is up to the engineers, provided acceptable safety can be adequately demonstrated to an independent federal agency legally charged with protecting the safety of the involved and non-involved public.

Why airworthiness is a legal and ethical necessity

To understand the legal need for airworthiness, we need to start with the roots of how a legal obligation for commercial safety came about. The legal obligation for business owners and operators to be responsible for the safety of their customers arose, per my understanding, nearly 4,000 years ago in the ancient Code of Hammurabi.

If a builder build a house for someone, and does not construct it properly, and the house which he built fall in and kill its owner, then that builder shall be put to death.

This criminal legal code—essentially an “eye for an eye” act of vengeance for a harm having been caused—was the basis of Western civilization’s law for several millennia. Two thousand years later, in ancient Rome, accountability expanded to hold a business owner at fault even if the act causing harm was done by an employee or slave. Roman law held that the shipowner and innkeeper “was to a certain degree guilty of negligence in having employed the services of bad men.” The owner incurred guilt even though someone else may have been directly to blame.

This Roman law obligation continued until the emergence of British common law in the 1400s. Not being a lawyer, my understanding is that British common law is based on the concept of legal precedence where court decisions (and British customs) establish the law going forward.

In the late 1500s and early 1600s, British common law established that those engaged in business with the public carried a legal obligation “to exercise his art rightly and truly as he ought.” Over time, this obligation became known as a “duty to care”. Those engaged in the transportation of people—legally referred to as passengers—clearly carried this obligation as it was not realistic that a passenger could know if a vehicle was roadworthy or a ship was seaworthy and adequately provisioned for the voyage. (It is my understanding that the commercial use of the term “passenger” implies acknowledgement of the “duty to care” obligation. Some companies now talk about taking fare-paying individuals to space rather than using the term “passenger.” This comes across to me as an intentional avoidance of acknowledging a duty-to-care obligation. Also, I believe some writers incorrectly use the term “passenger” when discussing what federal law now refers to as “spaceflight participants”. Such likely incorrect use only confuses the public.)

In the United States, each individual state defines the law governing the duty-to-care obligation for commerce within the state. However, for interstate commerce, the federal government regulates the duty to care obligation through its constitutional power “to regulate Commerce with foreign Nations, and among the several States, and with Indian Tribes.”

In the 1800s, as industrialization took hold, technology advanced rapidly. Construction with metals replaced stone and timber. Steam engines powered land and water transportation. Electricity was commercialized. By the late 1800s, injuries due to faulty construction and equipment failure increased significantly. Improperly prepared foods and drugs caused illness and death. Congress took steps to impose safety regulations to protect the public and workers from harm and to alleviate some lawsuits by having the federal government assume some responsibility for assuring safety. This was achieved by imposing design and operating requirements and undertaking independent safety inspections. Railroads were addressed first followed by food and drug regulation.

The emergence of the profession of engineering

The world’s transition to industrialization in the 1800s was enabled by the steam engine; the genius invention of Thomas Newcomen in 1712 which enabled a simple fire to produce useful mechanical power. Industrialization requires the ability to use metals in safety-critical applications—such as steam boilers—where failure can lead to injury and death. In addition to civil engineering—focused on roads, bridges, canals, and ports—mechanical engineering emerged to handle industrialization.

As the United States saw the need to regulate industrialization to achieve acceptable safety, the professional role of engineering changed accordingly. Engineers increasingly relied less on “rules of thumb” and more on scientifically-established principles and practices to design safety-critical machines and installations. Notable failures of boilers, bridges, and dams, as examples, hastened the awareness of the need for these changes. In 1907, Wyoming began the examination and registration of anyone engaged in engineering to clarify that a duty-to-care obligation existed for engineering works that impacted public safety and that only registered professional engineers could legally carry out such work. (A similar process now exists in many fields, such as architecture and medicine.) From this start arose the engineering ethical obligation, adopted by professional engineering societies, to protect the public from avoidable harm by using the best available principles and practices.

The emergence of airworthiness

In the 1920s, Congress passed laws creating the need for the emerging airline and aircraft manufacturing industry to achieve federal airworthiness certification. The fledgling airlines were suffering an unacceptable number of accidents. With airlines clearly interstate commerce, and with Congress taking steps and investing federal funds to promote air travel, the imposition of airworthiness certification to boost the public’s confidence in the fledgling industry’s safety was a logical step. The positive results speak for themselves. Air safety improved, making air travel increasingly common. Part of this process was the adoption of specifications and standards for the manufacture of materials and some parts used to build aircraft (e.g., fasteners), and for the methods used to design, build, test, and inspect aircraft. Many of these specifications and standards became military procurement specs and standards during World War II and the ensuing Cold War.

In the United States, airworthiness certification negates the need for engineers engaged in the human flight industry to be registered professional engineers (PE) or work for a PE. In other commercial engineering disciplines, the PE’s act of signing or stamping an engineering document or drawing acknowledges the PE’s legal responsibility for the work. (In a field where such a requirement exists, only a PE is properly referred to as an engineer.) If something goes wrong through error, the PE is held responsible. While there may still be independent inspections, such as building inspections, the PE remains legally responsible.

The federal civil, commercial, and military airworthiness certification processes essentially remove the requirement that a PE oversee and be responsible for the work. (However, within the aerospace industry, many engineers are PEs—doing this, often, to show personal adherence to professional ethical obligations.) The primary reason for this difference is that the airworthiness certification process includes substantial ground and flight testing, often including the ground testing of articles to failure to verify the conservatism of the predicted performance. Such destructive testing cannot be replicated for typical terrestrial constructions such as bridges, buildings, and dams. Government engineers and pilots, especially for military systems, have access to and often directly observe the airworthiness testing and undertake government flight testing.

In having the final say about the aircraft’s airworthiness, the federal government assumes the duty-to-care responsibility when it issues an airworthiness certificate. For civil and commercial aircraft, the Federal Aviation Administration (FAA) directs the procedures and processes to be followed to achieve and maintain airworthiness and correct deficiencies that are later identified. The military has comparable airworthiness procedures and processes but extends its oversight role to include performance and mission capability.

Benefits of government safety certification

Today, most businesses operate quite successfully within a framework of government safety oversight that limits the public or employee’s possible harm when they engage in commerce. Per my understanding, with the government inspectors’ independent approval, the business operator’s duty-to-care obligation is met. This shields the business operator from legal claims of harm except where negligence can be proven. Also, when an approved product or operation is used, no informed consent is required, absent some further consideration due to age or health. Obviously, this legal protection benefits commerce significantly. Of course, mistakes can happen and unexpected failures can occur that cause harm. When this happens, safety criteria and requirements are modified to try to prevent a reoccurrence. Impacted systems are withdrawn from service until appropriate inspections and changes are made and recertification is achieved. (The FAA issues Airworthiness Directives to mandate needed changes.) The intent of government safety oversight is not to prevent all harm, but to keep the occurrence at an acceptable very low rate such that normal commerce can proceed without undo concern or serious disruptions should failures occur.

An often-overlooked aspect of this safety regime is that it also helps to shield professionals working in private industry from legal risk. The business owners and operators understand that the safety of their product or service will be thoroughly reviewed by independent experts before commercial use can begin to verify that approved safety protocols have been implemented. Identified deficiencies will be corrected, often at a substantial additional expense. Intentional acts resulting in unsafe products or services may have both civil and criminal consequences. Practicing professionals benefit because independent safety certification helps to prevent unsafe products and services from entering commercial use and causing harm.

Airworthiness does not preclude technology advancement

As everyone is aware, there is a surge in interest and private investment in electric-powered, VTOL air taxis that will carry fare-paying passengers. Rather than trying to avoid airworthiness certification—perhaps by claiming that mandating airworthiness precludes rapid technology advancement—electric VTOL air taxi developers are working closely with the FAA to make sure that airworthiness is achieved.

One such prototype two-person air taxi has received an experimental airworthiness certificate permitting test flights with two people on board to simulate passengers being transported by the taxi. The pilot would remain on the ground as the vehicle only carries two people. The test participants cannot be fare-paying passengers. With final airworthiness certification, the air taxi would operate carrying fare-paying passengers even if this was just for a local “joyride” to see the sights from the air. There is no reason why this model of handling technology advancement should not be applied to commercial human spaceflight.

Informed consent use in commerce

Going back to the 1500s, common law established a duty-to-care obligation by those engaged in commerce to protect the public. Under some circumstances, such as war or piracy, this obligation is waived. In modern times, it has also been waived in some areas of intrastate commerce.

Informed consent in voluntary commerce—as opposed to medical treatment—ethically requires that a reasonable person understands the risks. One common example where state laws permit the use of informed consent is river rafting. While rafting is a form of transportation, whitewater river rafting is deemed to be entertainment and not subject to the duty-to-care obligation required for fare-paying passenger transport. The distinction appears to be that such rafting does not exist to transport a person to a destination.

Not being a lawyer, it is my understanding that the legal presumption is that the simplicity of rafting enables responsible adults to make an informed decision regarding the inherent risks of injury or drowning. Does the raft appear sound? Is the guide competent and not intoxicated? Are the water conditions abnormally dangerous, such as following heavy rains? Is the safety equipment, such as helmets and life jackets, in good condition? If customers conclude that they should be safe, they sign an informed consent waiver absolving the rafting company of liability in most circumstances. The state may impose some basic regulations, such as wearing life vests and helmets, setting a minimum age or physical condition, or not being intoxicated, but the rest is left up to the adult or, in the case of older children, the parent or guardian to decide. Hence, rafting, mountain climbing, and similar commercial activities are permitted because it is presumed that an informed decision regarding one’s safety can be made. Further, the adult can physically inspect the equipment and question the operators to enhance their understanding and evaluation of the risk.

State court decisions determine any exceptions to the use of informed consent. When harm occurred on one rafting trip, an attempt to sue under the duty to care obligation was turned back by the court because, per my understanding, an informed consent waiver had been signed and this was deemed adequate for this form of entertainment commerce. However, in another case, when harm occurred on a theme park ride, the state court decided that the duty to care obligation held, overturning the expectation that purchasing a ticket to the theme park constituted giving informed consent.

Imagine trying to apply an informed consent approach to the electric VTOL air taxis if used for pure sightseeing—a form of entertainment travel comparable to river rafting. Would a simple visual inspection of the aircraft provide sufficient information for a typical adult to ascertain its airworthiness? With no pilot, who would be asked pertinent questions? If being used as a taxi to a destination, would it be ethical for a company to demand its employees, as a condition of employment or advancement, use such an aircraft that lacked airworthiness certification, requiring instead that an informed consent be signed absolving the employer and the operator of legal liability?

Informed consent and commercial human spaceflight

No company, to the best of my knowledge, is currently seeking airworthiness certification of a commercial human spaceflight system. Thus, an informed consent approach appears to be the way commercial human spaceflight is now being pursued. The inherent presumption appears to be that a typical adult can, of their own accord, determine whether the risk is acceptable such as is now done for entertainment rafting. Obviously, human spaceflight systems will be far more complex than river rafts, theme park rides, or even, the new air taxis.

At what level of complexity does it become unreasonable to expect that a typical adult can, of their own accord, make a determination whether the risk is acceptable? Is it not the case that the inherent complexity of commercial human flight was why airworthiness certification was implemented: to take slick marketing and profit-seeking out of the safety decision process so that the air travel industry could mature and prosper? Imagine a commercial human spaceflight operator offering fare-paying service to transport people to Earth orbit. For commerce to develop in space, companies will require employees to travel to space. If it would not be ethical for the company to demand that employees consent to using air taxis that are not airworthiness certified, why would it be ethical to demand that they consent to travel to and from space on flight systems that are not airworthiness certified?

Today’s road to oblivion

With recognition that reliance on an informed consent approach to commercial human spaceflight is ethically wrong and, as courts may determine, contrary to the long-held common law duty-to-care obligation, it is clear that America’s human spacefaring enterprise is still dead in the water. Despite the billons being spent, America is not yet developing a true commercial passenger spaceflight industry.

As I have pointed out elsewhere, shortly after SpaceShipOne won the Ansari X PRIZE for private, suborbital human spaceflight, it was loudly touted that commercial human suborbital spaceflight was just a couple years away. Congress was told to stand aside and just let private industry takeover. More time has since elapsed without such a commercial capability coming into operation than it took this nation to land humans on the Moon after President Kennedy’s1961 speech. Further, the operators of the suborbital systems now being developed appear to plan to rely upon the informed consent approach to safety. What is being developed is fancy river rafting trips for the wealthy. While some people champion this as progress, clearly it is not.

The emerging electric VTOL air taxi industry is leading the way by embracing airworthiness as the means to provide a proper safety foundation for their industry. The federal government is working closely to make this a success. In sharp contrast, the US private commercial human spaceflight industry is on a road to oblivion. Strong federal government leadership is now required to correct this situation by focusing on airworthiness-certified “aircraft-like access to space” system development that will foster the creation of a commercial passenger spaceflight industry.

A US Space Force may require a military human presence in space to achieve the dominance that the President desires. For this reason, it is time for the military to lead in advancing America’s human spaceflight industrial mastery. As was done with the new US Air Force’s leadership in advancing jet aviation after World War II, such federal government leadership will enable military and commercial airworthiness-certified aircraft-like access to space to become as safe and routine as air travel is today.


In 1968, a year prior to the Apollo 11 landing on the Moon, as a teenager I traveled to New York City for the first time. Growing up in a middle-class suburb in middle America, this was a remarkable experience—almost an alien encounter given the tremendous lifestyle differences between NYC and my quiet suburban city.

By coincidence, the now classic science fiction movie 2001: A Space Odyssey was opening that week. Billboards harking the opening were everywhere. Along with a group of other teenagers on this trip, I made a point of seeing the movie. Stanley Kubrick, with the help of many aerospace engineers, had created a detailed, technically accurate depiction of what humanity’s spacefaring near-future could be. The realism of Kubrick’s vision of this future was visually staggering, especially with the Super Panavision 70 Cinerama version projected on the large screen of a major NYC movie theater—an immersive experience missed on the home screen.

Dr. Heywood Floyd’s trip to space aboard the Orion III spaceliner—the orbiter part of a two-stage-to-orbit, fully-reusable commercial passenger spaceflight system—caught everyone by surprise. Compared to the three-person Apollo capsule atop the massive Saturn V, an ability to travel to space in comfort as a typical flight passenger, while wearing a business suit, set the standard for what the future of commercial passenger spaceflight “should be.” It is a goal that, 50 years later, we are still struggling to achieve, puzzled why this has not yet happened.

The focus of this three-part article is on commercial passenger spaceflight safety—what this ethically means and how to achieve it now. Without acceptable safety, a real version of Floyd’s travels to and within space will simply not happen. Despite what some would have us believe, outer space will not be permanently opened to commercial development and settlement without first establishing acceptably safe commercial passenger spaceflight.

The key question, of course, is what constitutes “acceptably safe” passenger spaceflight. Developing acceptably safe human systems is fundamental to the ethical practice of engineering. For some—the extraordinary risk takers—a real threat of death is part of the allure of the activity, such as climbing Mount Everest. In the civilized world—which many like myself hope to extend into space—risk is intentionally reduced through the implementation of the best-available engineering principles and practices. For air travel, these are embodied in airworthiness regulations. To truly open space to civilization, we must now carefully select the ethical path to achieve acceptable passenger spaceflight safety. Otherwise, more time and—especially—hard-to-replace funding will be wasted.

I am addressing this question in three parts. In this Part 1, I critique a proposal to establish a “regulated self-policing” approach to commercial human spaceflight safety certification. Finding the proposed approach, largely based on NASA’s “human-rated” safety process, to be unethical for commercial passenger use, I explain in Part 2 why the airworthiness approach yielding acceptably safe passenger air travel should be extended to all commercial passenger spaceflight. In the concluding Part 3, I describe how to proceed with creating an initial commercial passenger spaceflight industry, including a technical approach for developing a “DC-3” passenger spaceliner, as the initial step in building a broader American astrologistics infrastructure.

Making spaceflight safety a national priority

On the recent 50th anniversary of the Apollo 11 landing, one evening national news broadcast featured a 58-year-old woman. She was excited about the possibility that the long-awaited commercial suborbital spaceflight participant rides—legally not commercial spaceflight passenger rides—were “about” to commence.

Mesmerized by the billionaire boys of space, the “objective” news media has turned a blind eye to the safety of their version of human spaceflight. It is reminiscent of the lead-up to the fatal 1986 flight of the Space Shuttle Challenger, which was to fly the first civilian, a teacher, into space. The inherent risk the teacher was taking was part of the mission hype rather than a serious discussion of whether the teacher was intellectually capable of understanding and assessing the risk of losing her life—of making a true informed consent. Flying on the Space Shuttle was, we were then told, almost as safe as flying on an airliner. On that early shuttle mission, the probability of loss of crew is now estimated to have been 1 in 10; not the 1-in-1000 the public was led to believe. Yes, 1 in 10! Do you think that she—a schoolteacher and mother—would have signed on had she known this? Would the public have accepted this? Of course not!

NASA had turned the process of selecting the teacher into a giant publicity stunt. The selected teacher became a national media star. After disregarding known safety hazards with the seals in the giant solid rocket boosters, problems exacerbated on the exceptionally cold launch day in Florida, as the teacher boarded the shuttle, looking every bit an astronaut in her flight suit, her safety was not NASA’s foremost priority. The shocked world watched her and the rest of the crew die live on NASA TV. NASA’s public image of flight safety integrity evaporated.

We are repeatedly told that human spaceflight is inherently more dangerous. In its “human-rated” requirements document, NASA says “that a certain level of risk needs to be accepted to conduct human spaceflight.” This thinking will only open space to the foolishly bold and brave—such as those who free-climb mountains or wingsuit glide down mountainsides—or those who are wealthy but particularly naïve. I believe this mindset will lead to more Challenger-like failures in the future, such as the loss of the crew of the Columbia in 2003 due to poor safety decisions.

America must change course regarding human spaceflight safety. Achieving acceptable commercial passenger spaceflight safety must be made a national space policy priority if we are to open space to development and settlement. To understand why changes are needed, the two current federal approaches to human spaceflight safety must be explained.

The current federal law regarding suborbital human spaceflight is simply bizarre and immoral

Returning to the woman wishing to experience suborbital spaceflight, per federal law, assuring her safety is unimportant to the government. Should she undertake a commercial suborbital spaceflight, she will be required to sign a comprehensive waiver absolving everyone, especially including the government, of any liability should harm or death occur. Federal law presumes the average person has the wherewithal to ascertain the level of risk involved and the integrity of the spaceflight operations. This is nonsense!

To further confuse the topic of safety, federal law forbids the use of the standard commercial term “passenger,” instead substituting “spaceflight participant.” Only lawyers understand the legal significance of this change with respect to the owner/operator’s common law “duty to care” obligation regarding the safety of their passengers. The change to spaceflight participant generally abrogates this obligation.

One the same day as the 50th anniversary national news broadcast, the local news reported that several rides at the state fair were shut down due to not being assuredly safe. One was permanently shut down because of visible corrosion. Several years ago, a person died when a ride at that state fair failed. Now, per state law and common sense, the safety of the ride participants is paramount to the extent that the state government took on the final responsibility to inspect the rides to ascertain their safety and close rides where the safety could not be assured by operational inspection.

In our litigious world, public safety is increasing in importance—except in the area of human spaceflight. Per federal law, there is no current requirement for the federal government to inspect and ascertain the safety of a commercial suborbital human spaceflight system except to protect the safety of the public on the ground or flying in the shared airspace. Isn’t this bizarre! A state government will inspect a fair ride called “Travel to Space” to protect the public’s safety, but the federal government will not inspect and certify the acceptable safety of a commercial suborbital human spaceflight system to protect an American spaceflight participant engaged in this legal commerce. The current 2004 federal law addressing suborbital human spaceflight is immoral and must be changed.

NASA is currently responsible for orbital American spaceflight safety

For human orbital spaceflight originating in the United States, there is no current operational capability. NASA ended Space Shuttle operations in 2011 without, for the first time in US history, replacing an important national infrastructure with a better, safer capability. With NASA able to purchase rides to the International Space Station (ISS) from Russia, NASA did not have a true operational deficiency driving the development of an immediate replacement system. Instead, NASA focused on developing the Apollo-like Orion capsule spacecraft to be launched on the expendable Space Launch System and paying for the development of two smaller, less capable space capsules to transport astronauts to the ISS. This is the commercial crew program.

My understanding is that, per federal law, the NASA administrator is the authorizing authority for approving human spaceflight on NASA systems. To implement this authority, NASA developed its “human-rated” approach to human spaceflight safety. The “human-rated” approach has evolved over the years. NASA NPR 8705.2C, Human-Rating Requirements for Space Systems, is the current statement of NASA’s certification process and requirements. The following two quotations outline the purpose and responsibilities:

The purpose of this NASA Procedural Requirements (NPR) document is to define and implement the additional processes, procedures, and requirements necessary to produce human-rated space systems that protect the safety of the crew and passengers on NASA space missions.

The Program Manager is expected to evaluate the intent of these technical requirements and use the talents of the development and operation team to design the safest practical system that accomplishes the mission within constraints. By doing so, the program is expected to arrive at an optimal solution that represents the best overall value considering cost, schedule, performance, and safety. [emphasis added]

Note that safety is the “and” requirement, establishing its apparent importance in the hierarchy of program manager responsibilities; perhaps reflecting NASA’s acceptance of “a certain level of risk” and designing the “safest practical system that accomplishes the mission within constraints.” I think it is fair to say that these are inferior to the public’s expectations of the importance of safety for commercial systems providing public transportation services.

Space Shuttle probability of loss of crew

The Space Shuttle system was developed and operated under previous versions of NASA’s human-rated requirements. After the conclusion of shuttle operations, NASA was directed by its independent Aerospace Safety Advisory Panel to conduct a retrospective assessment of the probability of loss of crew (LOC) throughout the 30-year operational life of the system. The figure below shows the results For example, an LOC probability of 1 in 10 missions plots as a value of 0.1 or 10 percent. Notations indicate what changes were made to the shuttle system that affected the estimated LOC. The Challenger mission was #25 while the Columbia mission was #113.

The panel’s 2011 report noted, “In the Shuttle’s case, the first flight risk as now retrospectively calculated was in actuality 1 in 12 for LOC, yet at least one analysis that existed at the time of the initial launch estimated the risk to be 1 in 1,000 or better.” If the earlier analysis had predicted a 1 in 12 LOC probability on the first flight and this was known to the public, would the shuttle ever have flown? (Note that the retrospective LOC probability through Challenger mission #25 was 1 in 10.)

NASA made improvements to the Space Shuttle system throughout its operational life. Many of these, especially with the main engines, were noteworthy technological advances. However, even at the end of its 30-year history, the LOC probability had only improved to 1 in 90. By then, there had been two mission losses with the second mission—Columbia in 2003—being lost due to known but unresolved hazards related to the expendable External Tank’s external insulation.

It is reasonable to suspect that NASA had an idea of the actual low shuttle LOC probability throughout most of the 30 years. This helps us to understand what NASA really means when saying, in NPR 8705.2C, “that a certain level of risk needs to be accepted to conduct human spaceflight” and designing the “safest practical system that accomplishes the mission within constraints.”

It took the actions of NASA’s quasi-independent safety panel—after decades of operations—to publicly identify this substantial discrepancy between the implied safety of NASA’s “human-rated” safety regime and what was going on. This indicates that safety is apparently not the priority within NASA as the public has been led to believe as it is hard to believe that the true state of the Shuttle’s safety was unknown within NASA. Essentially, “human-rated” safety was whatever the NASA astronauts were willing to sign on to do.

It is best to think of NASA astronauts as being comparable to test pilots from the early days of aeronautics. Test pilots were the final judge of the airworthiness of a new aircraft based on the technical information gained from close observation of the aircraft’s development and the “feedback” from close program associates. Like test pilots, astronauts are employees voluntarily engaged in providing a service to their employer. Many employees volunteer for dangerous jobs—first responders, for example. Even then, however, normal life experience in the United States today does not provide an appreciation of what a 1-in-10 chance of death really means. Americans haven’t experienced this level of risk since World War II-era combat such as bombing missions over Germany.

The SpaceX Crew Dragon commercial crew system

As previously mentioned, NASA’s commercial crew program is developing several additional means of transporting NASA astronauts to the ISS. Two of these, as seen above, involve the use of capsules that will be launched on rockets. Both are nearing their first human flights. Somewhat of a surprise, NASA astronauts will be the first to fly rather than company astronauts—a reverse of the normal flight test approach for government-acquired aircraft.

A SpaceX Crew Dragon test capsule, Demo 1, was the first to fly—uncrewed—to the ISS. On its return to the Earth, it was recovered and processed for further testing. The company’s plan was to fly it a second time, also uncrewed, to activate and test the ascent escape system during an actual ascent.

The Crew Dragon capsule integrates the rockets needed for ascent escape into the base of the capsule. My understanding is that this design approach was selected by SpaceX to enable the capsule to be used for other missions where a powered landing, rather than parachutes, would be used. The ascent escape rocket engines are called SuperDraco.

Prior to launching this vehicle on its second flight test, the capsule’s SuperDraco engines were to be test fired in a ground static test. Less than a second before ignition of the SuperDracos during this ground test, a fire erupted destroying the capsule. As of this writing, investigation into the cause of the apparent failure is ongoing, although SpaceX says the most likely cause appears to involve valves that allowed fuel to leak through prior to pressurization of the system just before ignition. NASA has not yet released images of the capsule after that test, although some images and video are available online.

SpaceX’s test program to that point appears to have been competently undertaken. After the failure, NASA commented that, “Over the course of development, SpaceX has tested the SuperDraco thrusters hundreds of times.” In previous tests, the entire SuperDraco abort system had been test flown, but in a test capsule. My impression is that the ground static test was the first for a flight capsule during which a previously undiscovered design, manufacturing, or assembly error resulted in the fire. For this discussion of commercial passenger spaceflight safety, the reason why the Crew Dragon needed an ascent abort system is important to understand.

How “human-rated” safety drove the Crew Dragon design

At the end of its operational life, the Space Shuttle’s estimated LOC probability was still only 1 in 90. For the follow-on human spaceflight systems, my understanding is that NASA initially aimed to achieve a 1-in-1000 LOC probability—comparable to what the public was led to believe at the start of shuttle operations. This LOC estimate was not just for ascent but covered everything from the time the astronauts arrived at the launch pad to their return to land. Some of the hazards were human created, such as incorrect manufacturing or assembly, while some were natural, such as solar flares and space debris impact.

Early full-mission LOC probability estimates apparently found that achieving 1 in 1000 would be difficult, especially with unknown natural hazards acting on skimpy capsules. Consequently, per my understanding, NASA set the LOC target at three times the last shuttle value, which is 1 in 270. For the Commercial Crew Program, SpaceX and Boeing elected to propose developing—and NASA accepted—transport systems using conventional rockets and space capsules. It was up to these companies to provide an integrated system with their LOC probability no worse than 1 in 270. (Note that preparing probability estimates are actually quite complex. Saying the probability should be no worse than 1 in 270 is a simplification.)

Had the proposed systems been “aircraft-like” by being fully-reusable, each production system could have been flight tested to establish its proper functioning and actual operational safety prior to delivery to NASA for use in transporting astronauts to the ISS. Under such conditions there would be no statistical justification for needing an emergency ascent escape system just as commercial airliners don’t have such systems. (As I will discuss in Part 3, NASA had the opportunity to develop such a system.) Historically, space launch rockets have a launch failure rate around two to three percent. For example, the October 2018 launch of the crewed Soyuz experienced an ascent rocket failure, initiating an emergency separation and recovery of the capsule. By accepting proposals for systems that were not fully reusable, the need for an ascent escape system was imposed by NASA’s “human-rated” requirements. NASA’s decision to accept such proposals was, apparently, an implementation of their core willingness to accept “a certain level of risk” substantially worse than that of an airworthiness certified system.

Using the historical rocket launch failure rate, the probability of a rocket failure would be around 1 in 50. Without an ascent escape system, the crew would, of course, be lost. Hence, the purpose of the ascent escape system is to boost the LOC probability to a minimum acceptable risk. As NASA said after the Crew Dragon test incident, individual SuperDraco modules had been tested hundreds of time. (New jet engines are similarly tested, often for thousands of hours simulating a wide variety of flight and engine conditions, including bird ingestion.) What the accident showed was that spacecraft incorporated elements not previously tested in the flight configuration, contained parts that had critical but undetected flaws in the as-manufactured condition, were damaged during installation or handling, and/or suffered from a previously unknown failure mode. Hopefully, the accident investigation will identify the cause.

With the destruction of the Crew Dragon spacecraft in the April test, my understanding is that the capsule being built for the Demo 2 mission, which was to fly the first humans to the ISS, will now be used for the uncrewed ascent escape system test. It is possible that, after any needed changes or added inspections are identified, the SuperDraco engines will also be ground static test fired before the flight test. If these two tests are successful, then the Crew Dragon “type design” will have been shown by ground and flight testing to meet this part of NASA’s human-rated requirements—provided the minimum analytical probability LOC remains better than 1 in 270.

As will be discussed in Part 2, once an aircraft’s type design is approved and production begins, flight acceptance testing of each production aircraft is independently conducted to ensure it is airworthy before being operationally used. Only then is an airworthiness certificate issued for each aircraft. At that point, the probability of a serious accident is very low—which is why airliners, or the Orion III spaceliner, do not have emergency in-flight escape systems. Contrast this with the clear need of the commercial crew vehicles to have an ascent escape system due to the rocket having a likelihood of 1-in-50 or so of failure. Also, unlike each production aircraft, the flightworthiness of each rocket and capsule system will not be tested prior to its operational use.

In 2017, commuter aircraft in the United States—operationally equivalent to commercial crew spacecraft—suffered a serious accident in one in around 80,000 flights, with one fatality in roughly 600,000 flights. (At this commuter fatality rate, the Crew Dragon could transport more than two million people to space without a fatality.) The major airlines suffered no fatalities that year despite flying more than nine million flights. This is an indication of the statistical difference between NASA’s “human-rated” approach to achieving the “safest practical system that accomplishes the mission within constraints” and airworthiness that achieves true acceptable safety.

Space Safety Institute proposal

Several months ago, the International Association for the Advancement of Space Safety and, primarily, the International Space Safety Foundation proposed to the federal government the formation of a Space Safety Institute (SSI) to certify commercial human spaceflight safety. (Note that the proposal also uses the term “passenger” when discussing future commercial spaceflight.) I was surprised when a copy of the proposal was not made available to the public. Following my Freedom of Information Act request, the federal government provided the version they had been given. (The version of the proposal I received appears to be a draft dated March 2019, which is just prior to the Crew Dragon test accident.)

The foundation proposes to approach commercial human spaceflight safety certification as is now done for many commercial products involving human safety, with some form of safety certification provided through a non-government body.

The purpose of this report is to provide the rationale for the establishment of a (commercial) Space Safety Institute in the U.S. as “regulated self-policing” entity. It would be an open consortium of industry, space agencies and regulators to efficiently perform standardization and certifications activities, conduct joint research, and provide educational and professional training opportunities, within a broad framework of mandated policies and rules…

The proposed Space Safety Institute builds on concepts, experience and practices of various programs and sectors and may be archetypal of future direction in other fields (e.g. aviation)…

In conclusion, the Space Safety Institute would support a regulatory model that can react quickly and efficiently to technological advancements while exercising effective controls on commercial space systems developments. The Space Safety Institute would perform standardization and system certification activities, as well as educational and research activities. The regulator would establish broad policies and keep a general oversight role of institute’s processes and activities, while concentrating on other issues, which lie outside the Space Safety Institute scope, as space traffic management and international coordination.

The Space Safety Institute proposal would make NASA’s approach to assuring astronaut spaceflight safety the basis for their certification processes.

Safety policy and technical standards used by NASA Crew Commercial Program represent an excellent reference from which U.S. commercial human spaceflight industry can develop policies and standards to be used on non-NASA suborbital and orbital commercial spaceflight programs. Furthermore, industry can use the NASA CCP certification program as model for developing their own independent third-party certification process. [Emphasis added]

The proposal’s inference that NASA’s safety standards are “excellent” prompted my previous lengthy discussion of how I see the adequacy of NASA’s “human-rated” safety requirements. Obviously, I do not agree that NASA’s approach is excellent. Especially, I do not believe that it is a suitable model for commercial passenger spaceflight systems.

What the proposed Space Safety Institute would do

The proposal states:

The SSI main mission would be to establish and manage a safety certification process for commercial human rated systems which is lean, effective, and does not stifle innovation. A process that allows maximum design freedom and quick and efficient reaction to technological advancement.

A careful reading of the SSI’s mission shows that certifying only systems with demonstrated acceptable safety is neither mentioned nor implied in this brief mission statement. Instead, the foundation argues to adopt the NASA human-rated approach as the logical basis for “A process that allows maximum design freedom and quick and efficient reaction to technological advancement.” I interpret this as the foundation arguing that safety must play second fiddle to technological advancement. Is this really needed?

The British and French developed the ground-breaking Concorde supersonic airliner in the 1960s within the commercial airworthiness regime. This was less than 20 years after the first supersonic flight. (We are now nearly 40 years after the first Space Shuttle flight.) Boeing developed their substantially all-composite 787 airliners within the same airworthiness certification regime. Today, many companies are developing piloted and unpiloted commercial passenger flying taxis within the FAA certification regime.

Experience in the real world of aeronautics shows that making safety a priority fits well within a disciplined and well-structured system engineering development program. Airworthiness certification does not stand in the way of progress, but actually lubricates the gears driving progress forward by minimizing operational risk and encouraging future investment, just as is now happening with flying taxis.

The Space Safety Institute’s role, sitting between the regulatory entity—the FAA—and private industry will need to be defined, probably through legislation.

The Space Safety Institute would be somehow a “middle-man” between the regulatory body and the commercial space companies for the benefit of both parties. The SSI would provide standardization and safety certification services as a “recognized organization” approved by and operating under oversight of the regulatory entity.

A part of the institute’s organization would be a Safety Review Panel. Here is how the proposal identifies the panel’s role:

The SSI Safety Review Panel (SRP) will be responsible for conducting flight safety reviews. The SSI SRP will assist the developer/operator in assuring that safety critical systems, subsystems and operations are appropriately designed and verified. Specifically, the SSI Safety Review Panel will perform the following functions:

  1. Assisting the developer/operator in interpreting safety requirements in a manner consistent with applicable requirements, and providing recommendations for implementation.
  2. Conducting safety reviews as ap¬propriate during various phases of system development and operation.
  3. Evaluating changes to system that either affect a safety critical sub¬system or create a potential hazard to interfacing systems, or crew.
  4. Evaluating safety analyses and safety reports, and processes Non-Compliance Reports.
  5. Ensuring the resolution of system safety issues.

At the successful conclusion of safety reviews cycle, the SSI Safety Review Panel Chair would submit a Certificate of Flight Readiness (CoFR) to the regulatory organization (FAA). [Emphasis added]

A key element of the panel’s proposed responsibility is “assuring that safety critical systems, subsystems and operations are appropriately designed and verified.” If the intent is to verify that each production system is demonstrated to be flight-worthy by independent operational testing, as is done with aircraft, then the panel is just undertaking the FAA’s governmental role in verifying airworthiness. In such a case, what is the value added of the SSI? Shouldn’t the FAA be organically capable of doing this?

If, instead, the Institute’s intent is to adopt NASA’s “human-rated” approach where independent operational testing of each production system is not needed in order to obtain a Certificate of Flight Readiness, then what real value would such a certificate have? The SRP’s certification appears to just become a checklist, not an independent flight-worthiness verification that would establish public confidence in the use of each operational system used for commercial passenger spaceflight services.

I conclude that the Space Safety Institute proposal is not an effective substitute for the federal government’s organic responsibility to ensure the acceptable safety of commercial passenger spaceflight, just as the government does for commercial air travel. Further, I believe the term “human-rated” should be banned from use when discussing commercial human spaceflight safety. It is totally misunderstood by the public and is, especially, misleading to those being asked to make an “informed decision” about their personal safety.

Segregate the commercial passenger spaceflight regulatory path going forward from NASA

NASA was created in 1958 to separate human spaceflight from military space activities at a time when Cold War tensions were very high. President Eisenhower, for several reasons, did not want any public focus on highly secret military space programs, primarily being undertaken by the Air Force, to enable satellite observation of the Soviet Union and to build an effective nuclear missile deterrent capability. The threat of a nuclear “Pearl Harbor”—first with bombers and, later, with ballistic missiles—drove Eisenhower’s national security priorities throughout most of his administration.

President Kennedy, also for various reasons, gave NASA a political shot of financial adrenaline with his human lunar landing challenge. Only months into office, and after both the Cuban Bay of Pigs fiasco and the Soviets putting a human into orbit, he needed a political win. He decided to literally shoot for the Moon. Billions flowed to NASA and its contractors to make this happen.

Not disparaging the substantial technological and scientific accomplishments made by NASA, it has become a political juggernaut. Despite plainly stupid decisions costing lives and limiting commercial space development, it is sustained by Congress persistently funneling non-military aerospace money to favored Congressional districts and states. That Congress has consistently acquiesced to NASA’s misleading “human-rated” approach to safety establishes the true unimportance of astronaut safety to Congress. That, in 2004, after the loss of Columbia, Congress legally made commercial human spaceflight participant safety also unimportant reinforces this conclusion.

What is OK for NASA is not necessarily good for everyone else when it comes to safety. Despite the clearly apparent dangers of NASA human spaceflight, it has no shortage of the bold and brave seeking the glory and rewards of becoming a NASA astronaut. More than 18,000 people applied to become NASA astronauts in the most recent application cycle. What has made this approach politically work for NASA has been the extremely low flight rate of NASA’s human missions, combined with the hero worship of astronauts, especially by children. When only a handful of missions are undertaken a year, as the Space Shuttle experience demonstrated, failures are sufficiently infrequent that Congress, after appropriate public handwringing, forgives and forgets so that the money can keep flowing to key Congressional districts and states. Meanwhile, the clear lack of safety makes meaningful conventional commercial investment unwise.

Given these circumstances, setting NASA apart and letting NASA handle its astronaut safety as Congress permits is appropriate. Congress holds NASA’s purse strings and, thus, controls NASA’s safety morality. However, proposing to use NASA’s commercial crew approach to safety as their “model for developing their own independent third-party certification process” for commercial passenger spaceflight is fundamentally unethical and the fatal flaw in the foundation’s Space Safety Institute proposal. True commercial passenger spaceflight will involve much higher flight rates requiring much, much lower analytical probabilities of loss of life. Acceptable commercial passenger spaceflight safety will not arise from NASA’s inherently broken safety system. Instead, we must turn to what has worked for air travel and extend this to all commercial passenger spaceflight: the hands-on federal government regulation of commercial passenger spaceflight systems to establish their airworthiness.


(ed note: there was a news story about how the Volkswagen company was selling diesel automobiles containing a "defeat device" used to fraudlently pass emissions testing)

Tobias Klausmann

     This got me thinking: in an SF universe with spaceships (and possibly FTL), there probably is minimum standard for what is allowed to zip around at kilometers per second, as soon as space stations and the like are involved. Who does the certification? Even if there isn't an official body that tries to keep everyone safe, there will be a consensus, however muddy, about what (not) to do.
     When steam engines proliferated around the industrial revolution, there were quite a few horrendous boiler explosions, leading to the formation of standard bodies that would certify (and spot check, after initial approval) boilers.*
     Naturally, enforcing these standards is very difficult, especially if ad-hoc repairs are somewhat common on long missions. What you flew out with may have been certified, but what you came back with is just a mess of chicken wire and duct tape.
     In the case of only grass-roots "standardization", justice for endangering others with your hunk o' junk may be swift and airlock-shaped.

     * Historical side note: The organization that (among other things) checked vehicles for road safety in Germany (TÜV) was a descendant of such an organization (DKÜV, Dampfkesselüberwachungsverein, boiler inspection association), but these days there are various orgs that do this.

Ron Fischer

     Border or port inspections. Out system you'd be on your own, but as you got nearer populated colonies or Earth you'd be boarded for an inspection, before proceeding. If I may say so this feels like a GREAT idea for some stories. Basically "Customs Police" in space.

Tobias Klausmann

     This naturally hinges on how the drive systems work. With choke points (like jump gates), this is easy, but with arbitrary-location jump drives, this becomes tricky. Naturally, arbitrary jump points are also a strategic nightmare, unless you can somehow see them coming, like jump-pre-echoes, for example.
     A problem I see with arrival inspections is that most ships can not be thoroughly inspected without a dock, and even then, testing all the fail-cutout machinery could easily take weeks, so short of having those components sealed, I don't see this as feasible, unless travel times are already in the neighborhood of months.
     It's also a question of system throughput: in a place where a hundred ships arrive a day and an inspection takes at least two days, you need an enormous amount of manpower to just do checks. And this manpower needs to be away from stations/ports, and thus becomes quite expensive.

Ron Fischer

     Interesting points. I wonder how its done now? Some of the inspection is done at the port of departure or even when a container is closed, no?

Tobias Klausmann

     There is a huge discrepancy between the two trades that come to mind first: aircraft and ships. For the former, airworthiness is a serious cost factor and it is baked into the manufacturing process of aircraft. For the latter, nobody gives a sh*t until something happens.
     The thing with space craft on mid- to long-haul service is that modification will probably be much more common. In a sense, they bridge the gap: they are as dangerous-delicate as aircraft, yet have away-from-port times as long as ships do (possibly longer).
     The problem is: a pilot is not expected to repair the aircraft mid-journey and there is often (but not always) a place to go in emergencies. A ship does not have that luxury, which, combined with a "healthy" dose of tradition and business sense means that repairs underway are somewhat common. The basic idea seems to be: if it floats, is not on fire or carrying disease, we're good.
     I am not sure how to solve the discrepancy when it comes to spacecraft. 

From a thread on Google+ (2015)

Spacecraft Registration

In the civilized parts of the galaxy, spacecraft will be subject to registration, the same way automobiles and other vehicles are here on Terra.

All vehicles will have something answering to a unique vehicle identification number.

Each vehicle needs to be uniquely identifiable. Why? Quite a few good reasons:

  • Liability Insurance (if the vehicle damages something or somebody)
  • Vehicle Insurance (if the vehicle suffers damage and needs repair)
  • Theft Insurance (if the vehicle is stolen)
  • If the vehicle was purchased by an installment loan
  • Vehicle Registration
  • Contracts (e.g., according to contract semi-trailer truck XYZ must be at location Alfa at twenty hundred hours to be loaded with cargo Bravo and transport it to location Charlie)

For these and other expensive issues you must be able to unambiguously identify the vehicle being referred to in the legal documents.

Ordinarily this is a straightforward process. But things get sticky in a rocketpunk future containing modular spacecraft with parts you can change as easily as Lego. Swap a few parts and you suddenly have a legal Ship of Theseus paradox on your hands.


To operate said vehicle within national boundaries, the vehicle will have to be registered with the nation's official vehicle bureau (including passing the minimum functional and maintenance requirements, and paying the registration fee ). Some sort of vehicle registration plate(s) will be issued displaying to the authorities the registration number associated with that vehicle and the vehicle's identification number. Anybody who has purchased an automobile is familiar with the concept.

Instead of a automobile registration plate, spacecraft will probably have some kind of Automatic Identification System (the thing that the Traveller RPG mistakenly calls a starship's transponder). In addition to being used by law enforcement and the military, this will probably also be required by space traffic control.

Registration of spacecraft actually exists in the real world: the 1974 Convention on the Registration of Objects Launched into Outer Space. However, the transparency of the registration is often subverted. Specifically there are satellites orbiting Terra that are pretty obviously military in nature but there is not a hint of this mentioned in the registration. See Critical issues related to registration of space objects and transparency of space activities (updated list of unregistered satellites).

A commercial spacecraft, unlike an automobile, has issues similar to a commercial cargo boat. So they too may seek to avoid certain legal and taxation entanglements by using a questionable "flag of convenience". Occasionally this tactic can backfire with catastrophic results for the corporations that own the vessels.


Before owning a car became typical, roads and highways (the few that existed) were never crowded. It was only after everyone started purchasing and driving their own vehicles—to work, school, even the grocery store around the block—that streets grew congested, rush hour became an everyday occurrence, and car accidents became an inevitability.

Space, despite its vastness, could be on a similar trajectory. With so many new flying objects being sent into orbit and beyond, many scientists say, we could be in for some dangerous collisions. One group at Los Alamos National Laboratory in New Mexico is trying to fix that with something ubiquitous among cars, but currently nonexistent for space mobiles: A license plate.

It’s unlikely we’ll ever fill our cosmic neighborhood with enough flying objects to create anything like a space traffic jam, where satellites have to slow down at specified times or travel in their own intergalactic lanes. But space, in all its low-to-no-gravity glory, poses its own challenges.

The majority of satellites and other fancy objects we send into the cosmos stay in low Earth orbit (LEO), around 400 to 1,000 miles above Earth’s surface. It’s far enough away from the planet’s gravitational pull, but not too far; this sweet spot lets an object orbit pretty much indefinitely without needing much help.

But scientists have taken advantage of this prime parking space for the past 60 years, so debris is starting to build up. There’s more space junk on the way, too. As of 2015, there are more than 1,300 active satellites orbiting the Earth. That’s in addition to the inactive ones, as well as old rockets and other defunct space junk stuck in LEO indefinitely. That’s likely to increase exponentially with the introduction of CubeSats, miniature spacecraft that can be sent into space by the hundreds, and the various companies that plan to install internet-providing satellites in the LEO. What a space jam.

But don’t things just float around up there like a giant game of bumper cars? Not even close, explains David Palmer, an astrophysicist at Los Alamos. While there have only been two really substantial space crashes, he says, one crash is all it takes to trigger catastrophe.

“The problem is that once you have one collision, it makes a lot of debris, and that debris can then collide. Eventually you get what’s called the Kessler effect,” he says. Debris keeps building up with each new collision, creating infinitely more crashes. If this begins to happen on a regular basis, it’s possible for so much space junk to accumulate that space itself becomes unsafe.

“We are close to the point where if we keep on going for a little while longer, we will be pushing over the edge,” he says. “Once that starts happening, it can progress for a decade or two until there is too much debris in low Earth orbit.” At that point, the chances of a collision (and subsequent Kessler effect) become so high that the benefits of sending another satellite into LEO don’t outweigh the risks.

The big problem is when satellites retire. While in use, nearly all have GPS devices that scientists can use to find them with radio signals. But once satellites are out of commission, so are those radio waves. The space junk just orbits, without monitor, indefinitely. If an active satellite seems like it’s going to collide with one of them, the owner can dodge out of the way. But once a point is reached where space junk is just colliding with space junk, researchers can’t move either bodies out of the way without an owner’s permission. And to know who it belongs to, you first need to know what the object is. “You would need the permission of the satellite owner even if it’s a 30-year-old piece of space junk,” says Palmer. There has to be another method—a foolproof identification system. That’s how Palmer sees it.

His past research studying pulsars gave him an idea. Pulsars are large space objects that spin and emit beams of light in opposing directions. As they spin their light beams appear to flicker, and scientists, like Palmer, have put a lot of effort into studying that flickering.

“I put those two things together and thought that if I could create a satellite that produced a periodic signal,” says Palmer, “then by reading that signal, we could create an accurate identification system.

So Palmer and his team developed a super-low-power, miniature device that emits a unique pattern of blinks in the form of a laser. They call it Extremely Low Resource Optical Identifier (ELROI) or, more casually, space license plates.

Meant to be about a square inch by square inch, these devices would sit atop any satellite bound for space. Using a laser diode (what many everyday lasers are made of), the device would emit a series of very short red laser pulses. These flashes would be extremely bright (as bright as a 60 watt bulb, from something that uses only one watt of total power), and would continuously flash a series of specific pulses for no more than a millionth of a second. It would then shut off for a thousandth of a second—a thousand times as long as it was on for. A telescope on Earth could pick up that series of flashes, and with the help of a computer program, decipher what specific satellite it was coming from.

Despite the satellite being hundreds of miles away from the ground, the message is still crystal clear, explains Palmer. The light is coming from a laser and is the exact wavelength of the color red. A filter in the telescope blocks out all other wavelengths, allowing that color to shine through. The blinking corresponds to a binary (composed of hundreds of 1s and 0s) serial number. Each satellite, like a car, gets its own serial. The code tells the identifier three things: The kind of satellite it is, who owns it, and the path of its orbit.

The goal, says Palmer, is to have the devices sit on satellites and remain powered for at least 25 years, if not indefinitely. The the device uses a huge percentage of its battery’s life during its split second of blinking, but then spends a thousand times longer charging with solar energy. It can do this repeatedly, says Palmer, for about 25 years. Palmer thinks the device will be able to run off of its solar cells indefinitely even after the battery dies, but it’s impossible to be sure.

Their next goal is to actually test the prototype. They plan to do so by working with a team at New Mexico Tech who are sending a CubeSat into space this coming January. CubeSats, says Palmer, are an ideal vessel to test the device on: They are tiny, 10 centimeter cubed satellites that can be sent up into LEO, often en masse, to perform small experiments.

Though the prototype is ready for a test launch, Palmer says, the researchers are still tweaking the design. The ELROI is currently about four square inches and one inch thick. In the future, the team wants to get it down to the size of a postage stamp, and use materials such that the entire thing costs under $1000. That way, he says, even a high school science class can afford to send one up to low Earth orbit. CubeSats' low cost (one can cost only $10,000 to build; launching them into space is a few tens of thousands more) means they can be used by small, private companies, university students, and even high schoolers. Make the license plate price any higher, says Palmer, and, “that’s a lot of cakes you would have to sell at the bake sale.”

With the license-plated CubeSats up in space, the researchers will attempt to identify the miniature spacecraft by pointing a telescope at them and translating the binary code. If all goes according to plan, the goal is to test them on bigger satellites, with the ultimate objective to get them on every satellite that enters space.

Palmer admits that ELROIs are not a perfect solution. If two satellites are indeed colliding, you still need to ask for permission from the abandoned space junk’s owner before you remove it from orbit. If there isn’t enough time to track that person down, knowing who they are might not help you avoid disaster. But identifying who owns the aged space junk is indeed a good first start. It might not be too long before low-Earth orbit looks more like a busy highway than a vast, endless entity. And then people may wonder how breezy that open road must have been, back before satellites needed laser-powered license plates.


If modular design is taken to its limit, "ships" will have no permanent existence. Instead they will be assembled out of modules and pods specifically for each run, much like a railroad train.

In that case, a ship's identity is attached to a service, not a physical structure. Example: the Santa Fe "Chief" was identified by a timetable and reputation, not a particular set of locomotive and cars.

From INTERSTELLAR TRADE: A PRIMER by Rick Robinson (2001)

(ed note: Veyndayk, Velmeran, Dveyella, and Keth are Starwolves. They are in the business of capturing warships of the stodgy bureaucratic interstellar Union and selling said warships back to the Union.)

     Soon they saw that it was Veyndayk, the cargo supervisor.
     "Business done," he said, stepping up to join Velmeran and Dveyella at the rail where they had been watching traffic pass on the level below.
     "Did you sell Keth back to the Sector Commander?" Velmeran asked.
     Veyndayk laughed. "No, although that might be a good use for old Starwolves. Farstell Freight and Trade bought back a shipment of clothing, conveniently packed in their own shipping containers. And (Union) fleet ordnance has just now payed us a finder's fee for an intact cutter."
     "A cutter?" Velmeran asked. Cutters were the smallest of the military ships, hardly bigger than a transport, and generally used only for police work.
     "My little joke," Veyndayk explained. "We took two intact cutters as riders on salvaged battleships, and one we have had sitting in a forward bay for the last year. We took them apart down to the smallest bolt and rebuilt the ships by taking parts at random. Now I am going to collect finder's fees on those ships in three different ports. That should give the boys in fleet ordnance fits, when they cross-check serial numbers of those parts."
     That appealed to Dveyella, who liked frustrating Union officials best of all. "You know, they will not be able to use those ships until they take them apart and rebuild them as they originally were."
     "You laugh, but that is probably the truth," the cargo officer said.

From THE STARWOLVES by Thorarinn Gunnarsson (1988)

Space Traffic Control

Outer space equivalent of terrestrial air traffic controllers. Monitors and controls the flight plans of local spacecraft. Generally only needed in "crowded" areas, such as the orbital space around inhabited planets, or on a mothership carrying lots of fighter spacecraft.


Air traffic control (ATC) is a service provided by ground-based controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of air traffic, and provide information and other support for pilots. In some countries, ATC plays a security or defensive role, or is operated by the military.

To prevent collisions, ATC enforces traffic separation rules, which ensure each aircraft maintains a minimum amount of empty space around it at all times. Many aircraft also have collision avoidance systems, which provide additional safety by warning pilots when other aircraft get too close.

In many countries, ATC provides services to all private, military, and commercial aircraft operating within its airspace. Depending on the type of flight and the class of airspace, ATC may issue instructions that pilots are required to obey, or advisories (known as flight information in some countries) that pilots may, at their discretion, disregard. The pilot in command is the final authority for the safe operation of the aircraft and may, in an emergency, deviate from ATC instructions to the extent required to maintain safe operation of their aircraft.

From the Wikipedia entry for AIR TRAFFIC CONTROL

Since the first human-made object was launched into space in October 1957, the number of objects orbiting the Earth has risen into the thousands. The term “space traffic” refers to all spacecraft (both active and inactive) and space debris that are currently orbiting the Earth. The current amount of space traffic in orbit is quite striking. According to NASA, there are more than 500,000 pieces of debris the size of a marble or larger, orbiting the Earth, travelling at speeds of up to 28,000 kilometers per hour, enough to damage a satellite or spacecraft upon contact. In fact, at that speed, even “tiny flecks of paint can damage a spacecraft”. Data provided by the United States Space Surveillance Network (SSN) quotes that there are around 21,000 objects larger than 10 centimeters orbiting the Earth and more than 200,000 smaller objects.

The variety of objects in space is large. Orbital debris comprises expired spacecraft, spent rocket boosters, individual pieces of space assets, and even objects such as gloves. The last few decades have seen a drastic increase in the amount of objects in the low Earth orbit (LEO) domain—between 200 and 2,000 kilometers in attitude—which is by far the most congested orbit and contains important space assets such as the International Space Station (ISS) and other crewed spacecraft, as well as the Hubble Space Telescope. The economic importance of the LEO domain is growing rapidly with the emergence of new space systems, comprising hundreds to thousands of small or medium-size satellites, for Earth observation and telecommunications. These new space systems create new space traffic risks and are themselves at risk from others satellites and debris.

The amount of traffic in space complicates the task of launching new satellites. Launch windows already depend on a variety of factors and thus must be very carefully planned. Windows for launch can be limited, and the need to assess space traffic to avoid collisions simply adds another factor for consideration. Today, more than 60 nations spend a portion of their national budgets on space projects and, increasingly, private companies are launching new objects into orbit. Over the course of several years, scientists have noted a stark increase in the number of times two space objects have passed closer to each other than the minimum distance generally understood as safe. Any object larger than one centimeter can cause damage to satellites and other space assets, and most space debris are uncontrolled travel at high speed. The “over-congestion” of key orbits greatly decreases their utility, as collisions become far more likely. Collisions between existing objects can create further debris, subsequently increasing the chance of collision and jeopardizing future space travel.

The feasible destruction of satellites and other space assets has many negative implications for research, military and communications technologies, which we rely on for logistical, commercial and scientific services. For example, the ISS must be frequently maneuvered to avoid collisions, which is costly. In 1996, the French satellite Cerise was damaged by the debris of a French rocket which had been launched 10 years earlier, degrading the satellite significantly. In 2009, a defunct Russian satellite destroyed a functioning Iridium commercial satellite in a collision, adding over 2,000 pieces of debris to the known inventory of space junk. Moreover, there have been instances of collisions involving tracked objects, with space debris twice causing the collisions, and a third incident involving a segment of an operational satellite which had exploded.

In addition, the Chinese anti-satellite (ASAT) weapons test of 2007, in which China destroyed one of its weather satellites in polar orbit to test a ground-based ASAT missile, caused enormous damage, adding up to 2,087 objects to the trackable space objects database and resulting in the production of over 35,000 smaller pieces of debris down to once centimeter in size. This incident sparked severe geopolitical tensions, as generating such a large amount of debris can drastically threaten other space objects following the same orbit. In general, the prospect of large quantities of uncontrolled objects in congested orbits has the potential to increase tensions between nations, particularly in a case where an uncontrolled and unidentifiable object were to collide with a nation’s military or commercial space asset.

Managing space traffic

Vital immediate concerns surrounding space traffic management include collision avoidance, improving the utility of less congested orbits (such as geosynchronous orbit), the congestion of Sun-synchronous orbit (SSO) and LEO, and dangers to human-rated craft. To mitigate such hazards, both space agencies and private companies are coming up with innovative responses. However, one should stress the fact than detecting and following small space objects in space, with optical and radar devices, is a very difficult technical endeavor. It has been historically mastered only by the United States, which maintains the major global database on satellite orbits; Russia (but the operational status of the system is unknown); France to a certain extent; and possibly China.

The US Department of Defense manages a very accurate catalogue on objects larger than a softball in Earth orbit. NASA also cooperates with DoD and they share the responsibilities for characterizing the satellite environment, which includes orbital debris. The Space Surveillance Network (under the structure of the DoD) can currently track and catalogue objects with a diameter between five and ten centimeters in LEO and up to one meter in geosynchronous orbit.

The risks of collision are divided into three categories, depending on the size. For objects with a size of ten centimeters or larger, maneuvers for collision avoidance are normally quite effective. Smaller objects are usually too difficult to track and too large to shield against.

Debris shields are useful especially for debris that is smaller than one centimeter. Ironically, shields could become debris themselves, as it happened in March 2017, when a debris shield about 1.5 meters long and weighing eight kilograms installed by US astronauts on the International Space Station was simply lost as it floated away. This shield joined the more than 21,000 tracked objects in space. This is, however, a rare occurrence as larger objects are not frequently lost (astronauts may occasionally lose smaller objects, but it is not common to lose larger pieces.) The previous known incident happened in 2008, when an astronaut lost half of her tool bag during a spacewalk, as she was working on a solar panel. Incidents such as these may be isolated, but the sheer quantity and speed of debris makes collisions risks very serious.

NASA has long-standing experience in setting guidelines for assessing the seriousness of threats related to the possible approach of orbital debris to a spacecraft. NASA started implementing conjunction assessments and collision avoidance for human spaceflight back in 1988 with the shuttle mission STS-26. In 2005, NASA implemented similar measures to mitigate the risks of collision for high-value robotic missions. The conjunction assessments for all the designated NASA space assets are performed by the DoD’s Joint Space Operations Center, which then informs NASA.

“Debris avoidance maneuvers” are normally based on calculations. If the probability of a collision is calculated to be greater than 1 in 100,000, a maneuver will be conducted, unless it would jeopardize the mission’s objectives. When the probability of a collision is greater than 1 in 10,000, a maneuver is automatically conducted, except for situations when the maneuver could lead to additional risks to the crew. These maneuvers can be planned and executed in a matter of hours and they normally occur from one to several hours before the moment of conjunction. On many occasions, however, the tracking data is not precise enough for maneuvers to be conducted so the solution can be that the crew is moved into the Soyuz spacecraft that transfers crew to and from the station. Indeed, the Soyuz act as “lifeboats” for crew members in the event of an emergency.

However, national space programs and private companies are developing advanced systems for tracking and classifying thousands of pieces of space debris, which are currently untracked. One effort to monitor space traffic is the Space Fence program, which is being developed by Lockheed Martin for the US government and will, according to the company, “make 1.5 million observations a day to detect, track, measure and catalog items as small as a baseball and will support catalog growth to 200,000 objects.” This project aims to increase the amount of space objects we are currently able to survey by a factor of ten. Other technological and engineering-based responses include proposals to create autonomous hazard avoidance systems for space assets. Space assets could also be equipped with maneuvering and controlled end-of-life re-entry capabilities, to avoid the generation of debris through collisions when an object becomes defunct. In the long term, experts have called for the establishment of space debris remediation systems, whereby objects can be removed systematically. In fact, there have been numerous proposals in this regard, including from Gecko technology, the EUSO telescope, Space Sweeper with Sling-Sat, and the Electrodynamic Debris Eliminator, among many others.

Other mitigation strategies are rooted in cooperation. The United Nations Office for Outer Space Affairs (UNOOSA), an intergovernmental body which implements decisions on outer space taken by the United Nations General Assembly and United Nations Committee on the Peaceful Uses of Outer Space (COPUOS), recommends providing the satellite owner with information on avoidance maneuvers and tracking data, from which point they can conduct their own cost-benefit analysis on how to best avoid collisions. In fact, some space agencies (particularly in the US, as stated before) and companies do collect and disseminate data to help satellite owners avoid collisions. Real-time, accurate positioning data for objects are crucial for establishing sustainable orbits. Additionally, geosynchronous data sharing allows space actors to more efficiently plan their maneuvers by creating a clear separation between stationkeeping spacecraft and mobile satellites.

Yet there are problems with collecting the data necessary to avoid collisions, as no state has, in principle, the right to monitor any other actor’s activities in outer space and thus cannot obtain sufficient or uniform data, even if, as stated before, the US satellite catalog is a de facto reference. Currently, states which have signed the 1974 Convention on the Registration of Objects Launched into Outer Space agree to inform the Secretary General of the United Nations about the details of spacecraft launches for which they are responsible. However, states do not currently share enough data among themselves, with several actors collecting their own incomplete data, such as through the SSN. Sharing this data in the interests of everyone would provide a solution to this issue, but the geopolitical sensitivity of revealing certain space activities (the US catalog is, for instance, silent on some US military satellites) discourages states from sharing such information. Aside from recommendations provided by international organizations, the private sector is increasingly making its own suggestions for space traffic management, as this sector has an obvious interest in maintaining the future usability of space.

Another solution to the issue of space traffic may be the allocation of certain orbits for specific activities. For example, there have been calls for the creation of various zones for robotic Earth observation and monitoring satellites and other zones for the disposal of dead satellites and waste.

An international framework for space traffic management?

Despite the possible technological developments which could mitigate issues stemming from space traffic, many onlookers question the effectiveness of fragmented engineering efforts, arguing instead for the necessity of adopting a comprehensive international regulatory framework for coping with space traffic management. Indeed, international space law remains largely based on the 1967 Outer Space Treaty and a few other treaties. Domestic laws and regulations provide some regulations on conduct for outer space activities, but currently there are no legally-binding international rules on space traffic.

However, discussions on the concept of space traffic management (STM) have begun. STM was a single item at the UN COPUOS Legal Subcommittee in 2016. Before that, detailed studies were conducted on this issue in 2006 by the International Academy of Astronautics (IAA) and in 2007 by the European Space Policy Institute (ESPI), with both papers expressing a deep concern about the lack of regulations and provisions required for a comprehensive space traffic management regime. According to these studies, current deficiencies in international regulations include the lack of compulsory pre-launch notification systems, in-orbit maneuvering systems, right-of-way values for space objects, rules for spacecraft transporting humans, zoning rules, debris mitigation, and regulations for reentry.

In their 2007 report, ESPI argued that an international treaty would be a starting point for creating a framework for STM. However, the sensitivity and state-centric nature of the international legal playing field has rendered this objective difficult. In particular, UN COPUOS has a reputation for extremely slow decision-making, with its member states reluctant to accept changes in regulatory frameworks. These claims are reflected by the organizations inability to pass any binding provisions for over 20 years. Topics such as enforcing regulations, establishing arbitrary measures to resolve disputes, and the possibility of sanctions are extremely geopolitically sensitive and thus contribute to slow progress.

Nonetheless, the current legal framework is clearly outdated and insufficient to regulate situations which now include non-governmental actors and private companies. Consequently, states and companies tend to focus on developing their own tracking systems, and organizations such as the International Telecommunication Union (ITU) have established regulations which have essentially become soft law. However, it is clear that a binding legal framework for regulating space traffic is absent. This absence is of great significance, as an active traffic management regime could allow tracking systems to move beyond simply establishing the location of space objects and invest them with the capability to understand the intentions and adaptable trajectories of various space assets. Such a system would have clear implications for global security, as it could reduce ambiguity and deception surrounding space objects capable of threatening vital space assets.


The challenges and potential solutions surrounding space traffic highlight the need to view space activity regulation as a comprehensive topic, which requires cooperative mitigation strategies.

As outer space is the last true global commons, it must remain available for global use, to the benefit of all humanity. The international community must act fast to design a system in which data-sharing on space activities becomes a norm and which incentivizes spacefaring nations to avoid the over-congestion of key orbits. In the future, it will be crucial to improve space governance in order to prevent new collisions. Coordination between all space actors in space traffic control must become a priority in order to keep space usable and to sustain our current activities in space for future generations. Another solution could be the creation of a group comprising representatives of all the major space nations, who would provide data from their countries and act as an apolitical body solving international problems.

Additionally, with the increasing economic importance of commercial space programs, the creation of space traffic control authorities for civil activities (on the model existing in civil aviation), could be considered, and a debate is going on in the US on the possible transfer of a part of space situational awareness (SSA) activities from defense organizations to a civil organization like the Federal Aviation Administration. Eventually, such a move could be replicated in other countries and perhaps extended at the international level.

From a geopolitical perspective, the importance of controlling space traffic is paramount. As states increase their reliance on outer space technology for military, communications, and scientific services, the stakes of potential collisions get higher. Without a means of regulating orbital activities in space, we risk heightening geopolitical tensions, but we can control this through greater international cooperation.


Thorpe strapped himself in the observer’s chair in Admiral Farragut’s control room and watched as final preparations were made for getting underway. The control room was a dome shaped compartment dominated by a full circumambient screen. The arrangement bore a striking resemblance to a planetarium. It allowed the display of any combination of televised views and computer-generated charts on the forward screen. With the dome switched to the hull cameras, the control room’s four acceleration couches appeared to be floating in space.

The great glowing ball of the sun hung low in front of Thorpe while a crescent Earth stretched beyond the dome’s horizon at his feet. Luna was out of sight somewhere aft. The cluster of reactors and habitat cylinder that made up the Sierra Skies PowerStat were clearly visible above the lighted limb of the Earth. Despite the presence of the sun, the stars glowed in all their electronically enhanced glory. The Milky Way was a silver band arching from left front to right rear across the dome.

“Sierra Skies Control, this is Admiral Farragut. How do you read?” Captain Olafson’s voice asked from somewhere behind Thorpe. The freighter had departed the power station half an hour before with a single pop of the ship’s reaction jets. They had been drifting slowly away from Sierra Skies ever since.

“Hello, Admiral Farragut. We read you clearly.”

“We just passed out of the inner zone. Request permission to accelerate to mid-zone speed.”

“Stand by, Admiral Farragut.” There was a thirty-second pause while the controller reviewed the ship’s flight path. Ten years earlier, a ship had departed one of the powerstats only to find that its orbit took it directly through the delicate power rectenna. Ever since that incident, approaches and departures had been tinged with paranoia. “All right, Farragut. We check you as being clear of the inner zone. You may accelerate as planned. You are reminded that it is a violation to light off your main drive until you are one hundred kilometers distant.”

“Understood, Sierra Skies. We will observe the hundred klick rule!”

“Good luck on your mission, Admiral Farragut!

“Thank you, Sierra Skies Control. Please arm the reaction control system, Kyle.” This last was addressed to the chief engineer who occupied the acceleration couch beyond the captain’s.

From THUNDERSTRIKE! by Michael McCollum (1989)

Almost all of the above discussion has revolved around a general war scenario, or at least some form of war.  But what happens if there is no war?  What about the missions like patrols, boardings, inspections, and interventions?  In this case, ambiguity is rampant, and thing get much more interesting for the storyteller and much more difficult for the soldier.

The scenario that most readily leads itself to this sort of interesting activity is one in which there are multiple space-going powers on or around a given planet.  This puts competing powers in close proximity, and throws out many of the rules of traditional space warfare.  Furthermore, this scenario is most likely to occur with respect to Earth, which means that there are almost certainly dozens of powers in orbit, adding a complicated legal mess to the situation.  The problem is that many of the concepts that exist on Earth with regards to jurisdiction have far less value in space.  Everything is constantly moving, generally with significant velocities relative to each other.  Defining any sort of “territorial waters” will be incredibly difficult, given that both the object that the “waters” are centered on and everything else is moving.  At a guess, territorial space will only extend as far as the standard safety zone around an object.  What exactly that will be is uncertain, but anything more than a few tens of kilometers is unlikely.  The size of the zone is small enough to not pose a serious impediment to navigation, and the zone itself might vary in size based on the nature of the object it is centered on, and the orbit said object is in.  Current ‘safety boxes’ for spacecraft vary somewhat in size.  The shuttle had a box that was ±5 km along its orbit and ±2 km in the other directions.  That of the ISS is ±.75 km radially by ±25 km in the other two directions.  These suggest that similar sizes may be used for the zones around future spacecraft.

The next question is what exactly gets jurisdiction.  The “territorial zone” is probably only going to exist around manned spacecraft in permanent, assigned orbits.  The logic behind this is simple.  In virtually all cases it prevents overlapping jurisdictional claims, and avoids giving people the ability to game the system.  It also limits jurisdictional claims to those that can be enforced, instead of leaving a complicated web of possible claims that are mostly pointless because nobody is around to enforce them.  This is not to suggest that unmanned craft and those not in permanent orbits would not have safety zones, however.  They simply would not turn the space around them into “territorial waters”.  

The small size of the safety zones (and the fact that it would probably be forbidden to pass through one unless one was headed somewhere inside the zone) makes the idea of routine boardings and inspections suspect.  The author is not an expert in space or admiralty law, but it appears that only under fairly restricted circumstances can craft be boarded.  It is legal for the flag state to conduct inspections anywhere in the world for purposes of safety and documentation (and possibly more, depending on local laws).  For any other vessels (in territorial waters only), the state must be affected by a crime, or it must have a request from the flag state to board.  These change if the vessel in question has docked in the state.  In international waters, suppression of piracy and slavery are about the only reasons involuntary boarding is allowed.

All of this casts doubt on any scenario that involves routine boardings, throwing the rationale for space fighters into doubt again, particularly given the spread of “flag of convenience” registration on the seas today.  If an inspection is required, it is probably better to do so when the vessel is docked at its destination, instead of spending the time and delta-V required to chase it down.  While the issue might occasionally come up, the presence of dedicated ‘boarding gunships’ is unlikely.  The ultimate arbiter of good behavior in this scenario is the threat of warships becoming involved.  While the boarding party might be lost if a vessel makes trouble, the crew of the resisting vessel will be as well, and they would know as much before they made trouble.  In many ways, the same situation is in effect today, and the number of cases where boarding parties are resisted is very small.

It has been suggested that some sort of international authority will be required to regulate orbital space, primarily for purposes of safety.   This authority could ensure optimal use of orbital space, quite possibly along the same lines that the International Telecommunications Union does for satellites in geostationary orbit.  In fact, given that the ITU plays a role in current spaceflight activities by ensuring clear communications, it is entirely possible that such an authority could evolve out of it.  Alternatively, the UN currently maintains a registry of ‘Space Objects’, which includes orbital data, and the registration system could evolve out of that.

The exact nature of the allocation of orbital slots is likely to involve thousands of lawyers and millions of man-hours, as the current system of first-come, first-serve is likely to prove inadequate under the increasing demands placed on space use.  One possibility is the creation of “bands” and the assignment of position within said bands.  A precedent already exists with the aforementioned ITU allocation of geostationary slots, although in this case the bands would be artificially created.  This policy recognizes the fact that for certain tasks, some orbits are more useful than others, such as the orbits used by GPS satellites, which have repeating ground tracks, or the sun-synchronous orbits used by many remote sensing satellites, which ensure consistent sun angles in the data.  Other applications, such as colonies and shipyards, do not have particular requirements, and can be placed in orbits that are not required for anything in particular.  In fact, the most optimal arrangement would be circular orbits with a number of craft sharing the same orbit, one behind the other.  These ‘rings’ allow virtually risk-free sharing of orbits while maximizing the number of slots available.  Certain bands may be designated for special tasks, such as deep-space arrivals and departures, with facilities in appropriate orbits for the various destinations.

It is also possible that the regulatory body would be charged with handling space debris problems, as a corollary to its primary duties.  The current problems with debris are unlikely to persist in a future in which there is significant activity in space.  While minor debris damage (paint flecks and such) are simply a fact of life, larger debris is mostly a result of the way space programs must be conducted.  However, there is no reason to abandon a satellite in the sort of setting under discussion.  Even if it is too old to be worth repairing, it is still a large amount of high-purity metal in orbit.  Instead of abandoning it and risking problems (not to mention tying up a potentially valuable orbital slot), an owner would probably scrap it in orbit or sell it to someone who would do so.  The same applies to upper stages of boosters, but to an even greater degree.  It might well be worth the sacrifice of a small amount of payload to allow the stage to reach a scrapyard, recouping much of the cost of the stage in the process.  Of course, this assumes that expendable rockets are still being used as the primary means of space launch.  If some other method is in wide use, the value of on-orbit material will drop.  However, so will the cost of recovering an older satellite, and novel launch methods will do nothing to alleviate congestion and debris problems.

Smaller, but still dangerous, pieces of debris would of course still exist, and be continuously generated by space activity.  Thus, some system (possibly a laser broom) would have to be constructed to deal with them.  Said system would continue to sweep the debris from orbit as they are generated, keeping the population below where it is today.  Prompt clean-up would eliminate a major potential source of debris, leaving orbital space much cleaner than it is today.  (Except in the case of a major war, as discussed in Section 6).

by Byron Coffey (2016)

The question of what actually constitutes ‘Sovereignty’ and what determines what is and isn’t a sovereign state is a complicated one.  There are two major theories.  One of them holds that a state is sovereign if and only if it is recognized by other sovereign states.  The other is that a sovereign state is one that has a population, a government, and territory.  Ultimately, however, the bar that a potential state on a celestial body must clear is very high.  When it comes down to it, sovereignty is defined by the ability to claim a piece of territory and defend it convincingly enough that others recognize it as yours.  Even during the Age of Discovery, when everyone was planting flags on every piece of land they found, control of the territory is ultimately what determined the eventual boundaries of national sovereignty, not what the law said they should be.  The same is likely to apply in space.  Particularly because of the Outer Space Treaty, any sovereignty claims made in space are likely to be either moot due to lack of enforcement, vague due to lack of test, or fought over.  The first case is most likely to apply in cases where someone claims an entire large body, such as the Moon.  Unless they are able to enforce their claim, it is both legally invalid and rather silly.  Such cases (and it should be noted that there are already several people who have claimed the Moon) are not a real precedent in space law.  

The second category is likely to occur before the third.  In this case, a much more limited claim of sovereignty is made, and because of the limited nature of the claim, it goes untested.  The most likely example is a case in which a small colony established for non-economic reasons declares independence and claims title to a small section of the surroundings.  This could be a group of people dedicated to making humanity multi-world, a religious group, or even just a bunch of people who want to set up their own state, and have the money to get into space.  Because they are not economically motivated, the financial impact on Earth is likely to be minimal, and there is no real point sending a large expedition to contest a bit of what the government might well consider tax evasion.  There are interesting questions about things like passports raised by this, but ultimately, it wouldn’t be worth anyone’s trouble to sort out.  Sealand on Earth today almost falls into this category.

The third category is that described above.  Someone stakes a claim to a significant portion of a planetary body, and then fights for it.  The resolution of the question then depends upon the outcome of the conflict.  It should be noted that this puts major powers who are not directly involved in a difficult position.  While supporting the revolt might well harm their rivals, it would also set the precedent that space colonies can be sovereign and independent of a state on Earth, something that is not allowed by the current Outer Space Treaty.  It’s entirely possible that this precedent would damp Earth support for any revolt.

by Byron Coffey (2016)

For more than five decades, a major element of human spaceflight has been mission control. A roomful of engineers and technicians has vicariously flown each mission with the crew in space, monitoring the health of the spacecraft, keeping missions on schedule, and acting as a resource when things went wrong. Apollo 13, famously, would not have made it home without the efforts of Mission Control.

That will change as we go deeper into space because of the time lag involved in sending and receiving radio transmissions. Delays of a bit more than a second at the Moon, for example, will become many minutes at Mars: too long for Earth to be intimately involved in the flight. Future commanders of deep space missions will have authority and responsibilities that no astronaut or cosmonaut has had to date. It cannot be otherwise.

In the Earth-Moon system, however, there’s no reason to suppose the mission control model won’t be maintained. Doing so will add a layer of safety that will still be extremely useful. Several nations are currently considering lunar and cislunar crewed missions, but so are a few private companies. With early successes, the number of private groups interested will increase, but not all of them will attempt to fly those spacecraft themselves. Some, perhaps most, will contract with operations companies to carry out what they want. With such transactions and capital building, a strong industry will grow.

Many people today, including the NASA leadership, argue for building infrastructure in cislunar space to support operations in space. They cite the need for fuel depots, maintenance sheds, and a human outpost from which to carry out various projects. All of that is true, yet Earth-based infrastructure is also needed.

As long as all of that is government activity, mission controls are already established in various countries. But for a cislunar economy to really develop, private human spaceflight will also need to develop. Will those crews simply be on their own? Obviously not. So, who will control those flights? One solution would be for private companies to contract with one or more of the government centers, but those centers will be busy with their own missions, such as the International Space Station and its future Chinese counterpart. Moreover, the staffs of the government centers, no matter how experienced, will not know the private vehicles inside and out. Private flights in private ships mean private mission control.

Any mission control will be a major undertaking. Private companies are trying to lower their costs by keeping payrolls down and relying on computers and expert software to automatically monitor spacecraft systems. Mission controls are different beasts, however. Both to carry out their functions and to command credibility in case of an emergency, mission controls need a depth and breadth of engineering ability as well as a powerful computer system and resource base. Lives will depend on them.

Individual companies can establish their own mission controls, of course, but a better approach might be for the industry to build a central control system, with each company making a contribution to the new organization. That organization would control all private human vehicles, thus quickly gaining experience and expertise with various spacecraft. At some point, it might make sense for the organization to become a corporation in its own right. That would allow it to enter the capital markets to improve its technology, broaden its services, and maximize its value. Becoming a separate legal entity would likely also simplify its effort to protect any corporate secrets to which it may gain access.

Infrastructure beyond Earth is critical to creating a cislunar economy, which is itself critical to opening the solar system. But infrastructure on Earth is also important. Private industry will need to be extremely efficient to extract profits from space operations, especially in the early years. Pooling resources to create an asset for everyone might make strategic sense.


      As Scott and Tom climbed the narrow stairs to the traffic-control deck, the Solar Guard officer continued to speak of the man-made satellite. "When the station was first built," he said, "it was expected to be just a way station for refueling and celestial observations. But now we're finding other uses for it, just as though it were a small community on Earth, Mars, or Venus. In fact, they're now planning to build still larger stations." Scott opened the door to the traffic-control room. He motioned to Tom to follow him.

     This room, Tom was ready to admit, was the busiest place he had ever seen in his life. All around the circular room enlisted Solar Guardsmen sat at small desks, each with a monitoring board in front of him holding three teleceiver screens. As he talked into a mike near by, each man, by shifting from one screen to the next, was able to follow the progress of a spaceship into or out of the landing ports. One thing puzzled Tom. He turned to Scott.
     "Sir, how come some of those screens show the station from the outside?" he asked. Tom pointed to a screen in front of him that had a picture of a huge jet liner just entering a landing port.
     "Two-way teleceivers, Corbett," said Scott with a smile. "When you arrived on the Polaris, didn't you have a view of the station on your teleceiver?"
     "Yes, sir," answered Tom, "of course."
     "Well, these monitors picked up your image on the Polaris teleceiver. So the traffic-control chief here could see exactly what you were seeing."

     In the center of the circular room Tom noticed a round desk that was raised about eight feet from the floor. This desk dominated all activity in the busy room. Inside it stood a Solar Guard officer, watching the monitoring teleceivers. He wore a throat microphone for sending out messages, and for receiving calls had a thin silver wire running to the vibrating bone in his ear. He moved constantly, turning in a circle, watching the various landing ports on the many screens. Three-thousand-ton rocket liners, Solar Guard cruisers, scout ships, and destroyers all moved about the satellite lazily, waiting for permission to enter or depart. This man was the master traffic-control officer who had first contacted Tom on his approach to the station. He did that for all approaching ships—contacted them, got the recognition signal, found out the ship's destination, its weight, and its cargo or passenger load.
     Then the connection was relayed to one of the secondary control officers at the monitoring boards.

     "That's Captain Stefens," said Scott in a whisper. "Toughest officer on the station. He has to be. From five hundred to a thousand ships arrive and depart daily. It's his job to see that every arriving ship is properly taken into the landing ports. Besides that, everything you've seen, except the meteor and weather observation rooms, are under his command. If he thinks a ship is overloaded, he won't allow it to enter and disrupt the balance of the station. Instead, he'll order its skipper to dump part of his cargo out in space to be picked up later. He makes hundreds of decisions a day—some of them really hair-raising. Once, when a rocket scout crew was threatened with exploding reactant mass, he calmly told them to blast off into a desolate spot in space and blow up. The crew could have abandoned ship, but they chose to remain with it and were blown to atoms. It could have happened to the station. That night he got a three-day pass from the station and went to Venusport."
     Scott shook his head. "I've heard Venusport will never be the same after that three-day pass of Captain Stefens."
     The young officer looked at Corbett quizzically. "That's the man you're going to work for."

     Scott walked over to the circular desk and spoke rapidly to the officer inside. As Tom approached, Stefens gave him a quick, sharp glance. It sent a shiver down the cadet's spine. Scott waved to him to come over.
     "Captain Stefens, this is Cadet Tom Corbett."
     Tom came to attention.
     "All right, Corbett," said Stefens, speaking like a man who had a lot to do, knew how to do it, liked to do it, and was losing time. "Stand up here with me and keep your mouth shut. Remember any questions you want to ask, and when I have a spare moment, ask them. And by the rings of Saturn, be sure I'm free to answer. Take my attention at the wrong moment and we could have a bad accident."
     Stefens gave Scott a fleeting smile and turned back to his constant keen-eyed inspection of the monitors.

     The radar watch was reporting the approach of a ship. Stefens began his cold, precise orders.
     "Monitor seven, take freighter out of station on port sixty-six; monitor twelve, stand by for identification signal of jet liner coming in from Mars. Watch her closely. The Venusport Space Line is overloading again...." On and on he went, with Tom standing to one side watching with wide-eyed wonder as the many ships were maneuvered into and out of the station.
     Beside him, oblivious of his presence, Stefens continued to spout directions. "Monitor three, take rocket scout out of landing-port eight. One crew member is remaining aboard the station for medical treatment. He weighs one hundred and fifty-eight pounds. Make balance adjustments accordingly…"

From DANGER IN DEEP SPACE by Carey Rockwell (1953)

     "Da. Engagement zones are expanded," Omer explains "United States, Europa, Bahia, all announce new requiremen five days ago.
     "Sounds like transition-to-war conditions."
     "Maybe. Commonwealth ships have had some problems. Some body soon maybe make a 'mistake' with a Commonwealth ship” Omer pointed out. "Or we get clearance that is wrong and take us into engagement zone. So I got from Kevin Graham new data showing positions of all orbiting objects and load into computer I will make sure clearance and trajectory do not lead us into danger."
     Twenty minutes before noon, clearance came over the up-link Omer checked it and gave me a thumbs-up. I accepted it. We made a straightforward departure with the catapult slinging the Tomahok into the air at a one-gee goose. I climbed out according to flight plan and watched while the air-breathers transitioned I scram-jet mode and finally lipped-over when the mains ignited at 60 kilometers. I wasn't particularly looking for anything happen at that point because we were still in international space over the Indian Ocean.
     The Tomahok was handed-off from Madras Center to Orient Center as we ascended through a hundred kilometers, expected something to happen then. It did.
     "Tomahok, this is LEO Orient Center. Amended clearance."
     It came on the up-link. Omer shook his head. "Bojemoi!" exploded. "Reject it!"
     "LEO Orient Center, this is Tomahok. Negative the amended clearance, sir."
     "Tomahok, what's your reason for refusal?"
     "What's your reason for issuing this amended clearance, sir?"
     "AmSpace Command request through LEO Canambah Center."
     "The amended clearance takes us into the engagement zone of Gran Bahia estacao baixo doze."
     "Tomahok, stand by. ... Tomahok, amended clearance: De-orbit for Woomera landing. We can't get you through."
     I knew what to do, and I let it all hang out. "LEO Orient Center, Tomahok. Negative the amended clearance. We are initiating no-clearance flight under I-A-R Regulation ninety-one- point-eight. We'll take her up to Ell-Five as filed under our responsibility to detect and avoid."
     Omer reached over and clapped me on the right shoulder.
     There must have been consternation in LEO Orient Center because it took several seconds for the traffic coordinator to acknowledge. "Uh, Tomahok, Center, roger! Service is terminated. Proceed on your own responsibility. Retain your current beacon code."
     I acknowledged and told Omer, "Get ready to thread the needle, Russkie! Let's see if we're good enough to make Ell-Five before somebody burns us with a hell-beamer! (High Energy Laser = HEL beamer)"
     There I was, flat on my back at 30,000 meters, nothing between me and the ground but a thin regulation.
     I'd invoked a seldom-used International Aerospace Regulation that harked back to Earth's oceans where a ship captain was an absolute monarch responsible for himself, his ship, and everything in it. It had been carried into the air by a rule that made the; "pilot-in-command" solely responsible for the safety and operation of his aircraft and everything in it, regardless of what traffic coordinators on the ground told him.
     In effect, I'd told the space traffic people I'd fly without their help.
Avoiding an engagement zone isn't difficult if you know where it is. Space is mostly empty.
     The various STC Centers would continue tracking our beacon to keep other spacecraft clear of us. Military trackers would do the same in case we broached their engagement zones, which would mean trouble for the Tomahok.
     I'd waived clearance while still under ascent thrust on our original trajectory to a 200-kilometer parking orbit. Our delta-vee margin was excellent

     "Russkie, I hope the League data's good," I told Omer. "Display our current flight path and the projected positions and engagement zones of other sky junk."
     "Blinking blips aren't in League data," Omer reported. The Kazakh became laconic when he was under pressure, probably because he was thinking in Russian and mentally translating into aerospace English with adrenalin pumping.
     I studied the display. A blinking blip indicated a polar orbiting satellite. In parking orbit, we'd broach its engagement zone.
     "There's our problem," I pointed out. "AmSpace Command recon bird. That's why the amended clearance. We'll burn out of parking orbit to miss him. What are the options?"
     Omer punched the keypad. A series of trajectories came on the display. "Take high delta-vee option. It will be obvious we're avoiding the reconsat."
     "But we may run into trouble with this one, Omer," I said, indicating another target with my finger. "It's displaying no code. What is it?"
     Omer queried the computer. "Not in League data. Unknown."
     "It's got to be registered! I'll query Center for identification."
     "Let it be for now. We handle when time comes," the Mad Russian Space Jockey suggested. "We take problems one at a time. Sandy, get us in parking orbit and watch engagement zones. I work on vector for transfer orbit to Ell-Five."

     Our burn out of parking orbit came as re-programmed. While, we were under thrust, we got a sensor alarm. "Targeting lidar!" I snapped. "Aerospace Force has seen us closing on the reconsat,"
     "We go laser-hard," Omer said, reaching for the switch.
     "Negative!" I snapped. "They'll see it, interpret it as a countermeasure, and try to burn us." I indicated another target on the display. "That's annotated as an unspecified military satellite; it's a ten megawatt hell-beamer."
     "Hokay, so we do a little tsig-tsag! Give me controls!"
     I did and continued to check displayed targets. Omer called out his actions. “Tsang plus-x ten meters per sec."
     I got a surface temperature warning signal. "Warning shot without a call. That's not SOP!" The Aerospace Force tapped the data stream from the world STC net and they knew we were the unarmed Tomahok out of Vamori-Free.
     "Maybe you got wrong freq. We did not broach engagement zone of reconsat, and now they see us burn into new trajectory. So we are out of hard place under rock for now. You fly now."
     Low earth orbit zone is tricky to work in. Velocities and closing rates are high. There isn't much time to detect, track, make decisions, and maneuver. It's full of sensitive earth-oriented reconsats that are automated and passive. They can't defend themselves or maneuver. Even though such unmanned skyapies are considered to be expendable scouts, my former colleagues were sensitive about them. Everyone knew where everyone else's were, and nobody bothered them for fear of retaliation. Fortunately, sensitive satellites advertised themselves with "no trespassing" signals.
     Hell-beamers were another matter. They were unmanned with auto defenses. Unless they spotted the proper beacon password— which we didn't have—they'd shoot at anything that broached their engagement zones. We had to stay clear of those. We'd been lucky once.
     Some that looked like hell-beamers weren't; they were decoys or legitimate R&D space telescopes. The sensor signatures were the same. If you wanted to find out if one was indeed a hell-beamer, you had to make a hands-on inspection which was very risky not only because of the auto-defenses but also because some of them were booby-trapped.
     Nobody liked the hell-beamers, especially the League of Free Traders. But the low-powered ones in LEO were no threat to people on the ground. And nobody had been burned in space by them, so they were tolerated as a necessary evil.

     Think of Earth as being at the bottom of a funnel-shaped well whose walls become less steep as you climb away from Earth.
     Paint the walls of the funnel in zones of different colors to represent the various space traffic control center jurisdictions. The ones nearest Earth at the bottom of the funnel are controlled from national centers that are, you hope, in communication with one another and swapping data. The ones further out are watched by seven other centers located in GEO. And the ones in the nearly-flat upper part of the funnel are four in number centered on L-4, the Moon, L-5, and a huge "uncontrolled sector" stretching around lunar orbit from 30-degrees ahead of L-4 to 30-degrees behind L-5 where there wasn't anything then.
     Now spin the funnel so the bottom part representing a distance up to 50,000 kilometers goes around once in 24 hours. Spin the top part from 50,000 kilometers altitude out to a half-million kilometers at the lunar rate of 29.5 days.
     Located on the walls of this madly turning multi-colored funnel are marbles spinning around its surface fast enough so they don't fall down the funnel. Some of them are deadly marbles; come close and you'll burn. Others are big and fragile, but massive enough to destroy your ship if you hit one. Still others are ships like your own, plying space for fun, profit, or military purposes. An unknown number of the last are capable of whanging you with various and sundry weapons.
     Your mission: without coming afoul of any of this, get to the flat tableland on top, then locate and dock to a group of fly-specks called L-5.

     Try it on your computer. Good luck.

     We'd run a gauntlet of low-orbit facilities and were coming up on geosynchronous orbit. Although we were several degrees above equatorial GEO where most of the civilian facilities were, we had to get through the web of military satellites in inclined geosynchronous orbit, weaving paths around the planet like a ball of yarn.
     Omer asked the computer to enhance the very weak returns from these stealthed facilities. We were going to come close to some Japanese and European targets, but not within their engagement zones unless they'd changed them and we didn't know it.

From MANNA by Lee Correy (G. Harry Stine) 1983 ]

      Was reading your quote from Lee Correy (Harry Stine's) book, and thought you'd get a chuckle from this.

     Harry Stine used to give talks about the necessity for intelligent space regulation, including traffic control, at Space Access every year. I heard those talks and that was why I wrote up the outline of what I thought a near-term space regulatory regime would look like.

     So when Congressman Rohrabacher was looking for how to help the industry, I was ready with "you know, I have this little regulatory reform". And that began the process that became the Commercial Space Launch Amendments Act of 2004.

     So in no small part, Harry Stine really paved the way for the real space regulatory environment.

personal communciation with Jeff Greason (2016)

Space Traffic Gallery

Orbit Guard

This is more or less the space-going version of the Coast Guard. They are not military so much as they are a cross between a law enforcement agency and a search and rescue body. A real world organization that does straddle the line between military and civilian is the United States Air Force Pararescue

Orbit Guard assets tasked with SAR duties will require specialized space rescue equipment.

Since the Coast Guard operates in the coast, the Orbit Guard operates within the Hill Sphere of inhabited planets. Using the analogy that planets are islands and deep space is the ocean, Orbit Guard spacecraft can be called "Littoral".

Though the question of territory is a bit unsettled. A boat in the coast of Great Britain is stationary around Britain. But an orbital spacecraft constantly moves in its orbit around Terra, passing over many different continental nations on its ground-track. This isn't a problem if the entire planet is under one government, only if it is balkanized.

There is no hard and fast division between the Orbit Guard and the Patrol. They sort of blur into each other. In some cases they might merge into one organization. The Orbit Guard is more biased to the civilian/search-and-rescue end of the spectrum, while the Patrol is biased more to the military/pirate-hunting end of the spectrum.

Yes, I originally used the term "Orbit Guard" for those tasked with preventing asteroid bombardment warfare. I changed it for reasons explained here.


A coast guard or coastguard is a maritime security organization of a particular country. The term implies widely different responsibilities in different countries, from being a heavily armed military force with customs and security duties to being a volunteer organization tasked with search and rescue functions and lacking any law enforcement powers. However, a typical coast guard's functions are distinct from typical functions of both the navy (a pure military force) and a transportation police (a civilian law enforcement agency).


Among the responsibilities that may be entrusted to a coast guard service are:

During wartime, some national Coast Guard organisations might have a role as a naval reserve force with responsibilities in harbor defenses, port security, naval counter-intelligence and coastal patrols.

The Coast Guard may, varying by jurisdiction, be part of a country's military, a law enforcement agency, or a search and rescue body. For example, the United States Coast Guard is a military branch with a law enforcement capacity, whereas the United Kingdom's Her Majesty's Coastguard (HMCG) is a civilian organisation whose only role is search and rescue. Most coast guards operate ships and aircraft including helicopters and seaplanes that are either owned or leased by the agency in order to fulfil their respective roles.

Some coast guards, such as the Irish Coast Guard, have only a very limited law enforcement role, usually in enforcing maritime safety law, such as by inspecting ships docked in their jurisdiction. In cases where the Coast Guard is primarily concerned with coordinating rather than executing rescue operations, lifeboats are often provided by civilian voluntary organisations, such as the Royal National Lifeboat Institution in the United Kingdom, whilst aircraft may be provided by the countries' armed forces, such as the search and rescue Sea Kings operated by the Royal Air Force and Royal Navy, in addition to any of the HMCG's own helicopters.

From the Wikipedia entry for COAST GUARD

The National Space Society (NSS) is proposing a transparently operating civil US Space Guard with a national and collaborative international scope of operation. Such a civil Space Guard would initially be established and funded with the capacity and responsibility to: (a) license and regulate US civil and commercial space activities, other than as currently conducted by the Department of Commerce (DoC) space offices for various functions, by the Federal Communications Commission (FCC) for radiofrequency spectrum, and by the Office of Commercial Space Transportation in the Federal Aviation Administration (FAA) for rocket launches; (b) monitor and guide US civil and commercial space activities pursuant to applicable international treaties; (c) enforce US civil and commercial space regulations; (d) coordinate with US civil and commercial space and aviation offices to enhance efficiency, safety, and space traffic management; and (e) engage the international space community in collaborative efforts to advance space development throughout Earth orbit, cislunar space, lunar surface operations, orbital spaces, solar system planetary bodies, and beyond.

In the future, the US Space Guard’s role would expand by adding the capacity and responsibilities to: (a) carry out inspections and enforcement related to unlawful activities in and around restricted commercial safety and work zones established by US civil and commercial entities; (b) license and regulate US civil and commercial orbital debris removal technologies and missions; (c) maintain US civil and commercial navigation aids, shelters, and other space infrastructure (where no licensed missions are tasked); (d) carry out in-space search and rescue of US persons and property and collaborate internationally on such search and rescue per US agreements, including US-ratified international space treaties; and (e) as the lead US agency, coordinate national space offices and collaborate with international space offices for planetary defense against near-Earth objects and extreme solar events.

NSS suggests that a feasible pathway to creating a national civil Space Guard would be to evolve it from the Commerce Department’s uniformed NOAA Officer Corps, or NOAA Corps.

Why does the United States need a civilian Space Guard?

The next 15 years will see a dramatic increase in the number of rocket launches competing with commercial airliners for airspace before reaching orbit. In coordination with the FAA, the aviation and space industries have begun to work together to find and implement technical solutions to avoid long periods of airspace closure.[1] However, beyond airspace congestion lies orbital congestion, represented by 2,000 working satellites and more than 8,000 tons of debris.[2] Beyond Earth orbits, civil and commercial in-space vehicles and all manner of in-space infrastructure will eventually be populating cislunar and other orbital spaces. A likely ten-fold increase in launches and orbiting satellites during the next 15 years calls for better coordination among all the civil air and space offices in the US federal government, complete with greatly enhanced space situational awareness and space traffic management. In this connection, NSS has recommended that the proposed Space Guard have lead responsibility for comprehensive Space Traffic Management.[3]

When rockets launch to orbit from US coastal sites, where they fly over water instead of populated landmasses, the US Coast Guard (USCG) clears boats from entering the hazard zone.[4] In peacetime, USCG maritime activities are wholly focused on the protection and safety of persons and property, that is, guardianship. Such guardianship will one day also be needed in the space environment. A civil and transparently acting entity will soon be needed with the capacity to:

  • Regulate: license and regulate US civil and commercial space activities to the extent not currently covered by DoC, FAA, and FCC, including: missions to test, build, operate, service and maintain in-space vehicles and infrastructure; activities not involving the direct provision of telecommunications, media or information services to users on Earth (e.g. space tourism, in-space manufacturing, cislunar and lunar surface missions, space solar power, asteroid mining); and standards and licensing for orbital debris mitigation and remediation;
  • Organize: Based on previous NSS recommendations,[5] organize and enable safe US civil and commercial space activities related to comprehensive space traffic management, while promoting and coordinating with analogous entities internationally;
  • Guide: monitor and guide US civil and commercial space activities and policy formation pursuant to applicable international treaties;
  • Enforce: carry out the enforcement of US civil and commercial space regulations through fines, license revocations, or other means;
  • Enable: provide coordination for US civil/commercial space and aviation offices to enable a vibrant commercial space economy; and
  • Collaborate: engage the international space community in collaborative efforts to advance space development throughout Earth orbit, cislunar space, lunar surface operations, orbital spaces, solar system planetary bodies, and beyond.

NSS also envisions a time in the near future where the US Space Guard will need to evolve to handle several new responsibilities analogous to the responsibilities of the Coast Guard in the maritime environment. These responsibilities will require expanded new capacities and funding to match a rapidly growing commercial space economy:

  • Inspect and enforce: carry out inspections and enforcement related to restricted US civil and commercial safety and work zones;
  • Mitigate and remediate: set standards, license technologies, and regulate US orbital debris mitigation and removal;
  • Protect: maintain navigation aids, emergency shelters, and other space infrastructure (where no licensed missions are tasked);
  • Search and rescue:[6] carry out in-space search and rescue of US persons and property and collaborate internationally on such search and rescue per US space agreements, including US-ratified international space treaties; and
  • Defend: as lead agency, coordinate national space offices and collaborate with international space offices for planetary defense against near-Earth objects and extreme solar events.

A military entity could theoretically carry out some of the proposed guardianship activities, like the rescue of persons and property. However, such guardianship taskings would distract from and possibly hamper its war-readiness. Another difficulty has to do with the international nature of these future proposed duties. Dozens of countries claim to have a space program, and 13 countries have already built rockets and launched them into space. Moreover, most of the debris in orbit is the result of launches by Russia/Soviet Union, the United States, and China, and the removal of most of this debris will take collaboration among the three countries.

A war-fighting arm of the US government would be hamstrung in collaborating with non-allies to remove debris or resolve other international space issues. The necessity to maintain military advantage over perceived or potential enemies brings with it the requirement to closely keep technology advancements, tactical protocols, and overall military strategy secret. To maintain its war-fighting advantage and effectiveness, a military force cannot operate openly and transparently, except in constrained areas with military allies. This secrecy requirement, plus its perceived attack capability, would greatly handicap its ability to help manage international space traffic or remove space threats through collaborative international action.

A transparently operating civilian Space Guard, however, would not be hampered by the above military-related issues.

A rational pathway to US Space Guard

The National Oceanic and Atmospheric Administration Commissioned Officer Corps (NOAA Corps) is one of the nation’s seven uniformed services. NOAA Corps officers are an integral part of NOAA, an agency of the US Department of Commerce. The NOAA Corps today provides a cadre of professionals trained in engineering, Earth sciences, oceanography, meteorology, fisheries science, and other related disciplines. Corps officers operate NOAA’s ships, fly aircraft, manage research projects, conduct diving operations, and serve in staff positions throughout NOAA.

The NOAA Corps reports to civilian authority and no congressional authorization would be required to evolve it into the US Space Guard. The Commerce Secretary can simply adapt its mission, but Congress would need to pass legislation to appropriate funding. NSS therefore finds it feasible to create a transparent, civil US Space Guard by evolving it from the NOAA Officer Corps to carry out the proposed guardianship, coordination, and collaboration duties described in this paper.


NSS suggests that a US Space Guard evolved from the NOAA Corps can provide the guardianship duties proposed above and provide coordination for the various currently dispersed executive space and aviation offices, especially as connected to space traffic management. NSS also suggests that the proposed civil entity, housed within the Department of Commerce and coordinating with executive space offices throughout the federal government, can help evolve industry best practices into an enabling governance framework to facilitate US civil and commercial space. As a non-military guardianship and coordinating entity, it’s great advantage will be its ability to work transparently and collaborate both nationally and internationally.


  1. Davenport, Chris et al. “Gridlock in the Sky,” The Washington Post, December 12, 2018.
  2. See this article. Note: 7600 tonnes = 8377.566 tons.
  3. See this white paper
  4. Davenport et al. Op. cit.
  5. For a useful definition and full discussion of space traffic management, see “Space Guard: A New Organization to Facilitate Safe Space Activities”.
  6. Search and rescue in the space environment would operate as in the current maritime environment. As such, these capabilities would lessen the need to strive for absolute self-reliance in space. Such in-space self-reliance, under the current aviation model, requires complex and costly multiple layers of redundancy.

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From SPACE RESCUE by James Oberg (1975)

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From Astronautix: APOLLO RESCUE CSM

Longtime commenter Ferrell made an observation about growing space traffic in the discussion on Adventures in Orbital Space that fits neatly into the setting portrayed in The Weekly Moonship:

At some point, traffic control and enforcement would be needed to keep ... impending chaos under control. As more people start working in orbit, the more positive control will be needed, traffic growing exponentially.

In a word, yes. A rudimentary framework for space traffic control already exists; I believe that orbital slots, at least in geosynch, are assigned by the International Telecommunications Union. But as space traffic grows, so will the need for traffic management and enforcement, as well as emergency response services. On land these tasks are commonly divided between police and fire agencies; at sea they are combined in the Coast Guard (at least in US practice).

The mission will eventually call for suitably configured and equipped spacecraft. And like the Coast Guard and its cutters, the agency and ships will in some broad sense be quasi-military in character.

Okay, let's be honest. This blog does not encourage war in space (or anywhere else), but that certainly hasn't kept me from writing about space warfare, or kept you from reading about it. But here I specifically want to look at what may be called 'organic' military or at least quasi-military activity in space — missions that relate to other human space activity, not just earthly power politics.

The distinction is important in more than one way. Navies have historically been 'organic' to sea trade (even if the first mission of the Royal Navy was and is to prevent another 1066). For that matter, armies have generally been 'organic' to the lands they defended, oppressed, or both.

Even more to the point, several great powers already have large military space armadas, and have for half a century. We call them ICBM forces, and neither as spacecraft nor as weapons are they really all that interesting. This isn't just Armageddon aversion — their 1950s predecessors, the B-52 and TU-95 Bear intercontinental nuclear bombers (both still in front line service, though mainly in other roles) had just as horrific a mission. But they were and are seriously cool airplanes, indeed acknowledged classics. You can enjoy and agree with the message of another Kubrick movie of the 1960s; those B-52 sequences still totally rock. Yee-haaaa! Yee-haaaa! Yeee-haaaaaaa .....

I think we can draw a broader message from this. The spacegoing equivalent of a coast guard cutter may not match the Romance quotient of a 44-gun frigate close-reaching to windward, a bone in her teeth and her guns run out. But it is probably more interesting technologically and operationally than a robotic battle station designed to vaporize other robotic battle stations or the occasional city.

And, most of all to the point, the coast guard cutter is in almost every case a far better delivery vehicle for a payload of adventure.

So how does it emerge? I will start with the agency that deploys it, the Space Authority. This rather bland name is inspired by the Port Authority of New York and New Jersey, an agency that in its mid-20th century heyday, under Robert Moses, was notoriously powerful and independent, and reshaped New York City (albeit in ways that are now widely deplored).

The Space Authority was founded in 2022 — or it might have been 2012; I haven't double-checked, and in its early decades the Authority was all but invisible. Its overall mission was and is to co-ordinate space activity, assigning orbital slots, enforcing safety regulations, and such. The Authority was set up by the major space launch players, but its guiding force was — and this is not a contradiction in terms — a shrewd, tough, and above all visionary bureaucrat.

To avoid endless wrangling over a tiny budget, this individual proposed a dedicated funding stream, a $10,000 fee for every ton placed on orbit. To the power players this was convenient and cheap, the fee coming to about 0.1 percent of contemporary launch cost. Even to penny-conscious Elon Musk it was chump change (and Musk might well have seen through the game and still figured it was worth playing, and paying).

And since space traffic had been fairly steady for decades, a few hundred tons annually, hardly anyone expected conditions to change. The Space Authority had just enough money, a few million per year, to rent some office space in Geneva or wherever, and hire a couple of sharp young attorneys as staff. Space law enforcement, in this early era, did not mean spacecraft with flashing red lights. It meant a letter, hand delivered on real paper (lawyers likes that stuff), directing attention to Section 28, Subparagraph h(3), 'Penalty for Noncompliance'.

Time marched on, and space traffic volume grew. By the time the moonship Henry Mancini is docked to Airlock 10-A, 100,000 passengers and 70,000 plus tons of cargo payloads are going into space every year, plus the upper stages of the shuttles that put them there. The Space Authority budget is now on order of a billion dollars a year, current value. Still chump change by Pentagon standards, but this is a real budget, enough to charter or buy and equip a couple of ships for special missions — and develop a more capable, purpose-built model. The need may not yet have fully arisen at the level I described, with its 6-8 passenger ships operating beyond low Earth orbit. But it is clearly on the horizon.

The primary mission of these first Patrol ships will likely be the noblest: space rescue. Rescue in deep space is problematic at best; the distances are simply too vast. By the time you reach a stricken ship or outpost it probably won't have any survivors left to rescue. But rescue in orbital and local space is a different matter.

We have already had a case where space rescue could have made all the difference. Had the extent of damage to Columbia's heat shield been recognized, a rescue mission would have been feasible in principle. I sadly suspect that NASA closed its eyes and grit its teeth because no rescue was possible in practice. Even the Russians, with their simpler, robust architecture, could not have cued up a double Soyuz mission in time, and Columbia was on an orbit that Soyuz, from its high-latitude launch site, probably could not reach.

But once space rescue is practical it is necessary, and the Authority needs a ship or two that is up to the job. This means sacrificing operating economy in favor of flexibility and performance, specifically the ability to deploy on short notice and reach as many orbits as possible, meaning plenty of maneuver capability, AKA delta v. Onboard equipment and facilities, in addition to sick bay, likely include storage and support for taxi craft and robo pods used to work around crippled, possibly tumbling spacecraft, plus a miniature onboard Mission Control for directing operations.

The first such ships will be handbuilt prototypes, thus costly; the Authority might need to issue revenue bonds to fund the development program. Follow-ons will be less expensive, though still more than commercial models since the mission is more demanding. Say $200 million per ship for a 100-ton ship (unfueled), and $60 million per year to keep each in service, plus propellant for training missions. Perhaps $150 million annually per ship, all up, so the Authority can keep three or four in service.

And it possibly has not escaped your attention that the major characteristics of these ships — their flexibility and performance — are very much what you would expect of warcraft. Throw in fittings like those (potential) weapon bays and CIC or tactical control center and you have the raw material of a handy basic space warship.

Even militarized, these Patrol ships would be no match in sheer firepower for the sorts of weapon platforms the great powers might deploy. But they are far better suited to exerting a presence in orbital space. Über battle stations leave policymakers with a pretty stark options menu — nothing between issuing a sternly worded letter of protest or blowing someone up. A Patrol ship can switch out the medics for a SWAT team, go out to any orbit, arrest someone, and haul them in to face charges.

And that is how you effectively and flexibly exercise power, or dare I say Authority, across local space.

What are the chances of some such agency and some such ships emerging? Given the scale of space activity I have portrayed — hardly a given — I'd actually rate the chances moderately high, say five percent to 20 percent. Someone will need to do it. The great powers won't trust each other, and won't want to spend their own money on forces suited to keeping order in orbit rather than overawing their terrestrial rivals. Business interests will want some law and order up there without getting too entangled in international power politics. Yet the outcome suggested also would mark, quietly, a beginning for space-centric political structures.

On Independent Orbit?

Potentially, at least for purposes of opera, it might be a good deal more than that. As noted here before on this historically significant anniversary, the Revolt of the Colonies has been a long-standing theme in space-oriented SF; particularly, for obvious reasons, 'Murrican space SF.

In the rocketpunk era the Space Patrol was commonly understood to be an arm of the American Empire Terran Federation. As such it would be cast in the role of the Redcoats in any Independence Day scenario. (Though, notably, Heinlein in Between Planets did not call the Federation forces, or any component of them, the Patrol; that name was reserved for stories where the Patrol and the Federation itself were good guys.)

But the Patrol as outlined above arises in different circumstances, where there is no Federation, certainly nothing like a world state, only the great-power muddle we have known since 1648 — or perhaps even a more thorough muddle, known to students of international affairs by the wonderfully Game of Thrones-esque name of neomedievalism.

In such circumstances, as suggested above, the Patrol is not an instrument of any terrestrial power, but one that arises from the circumstances of space itself, politically embodied in this account by the Space Authority. No one on Earth quite owns it, or can even agree on who should own it.

There would likely be no Declaration of Independence, no need for a gifted rhetorician to remake poor old George III into Caligula. Possibly the last thing the Authority wants is to call that kind of attention to itself and its expanding role, and gaining a seat in the UN General Assembly, or successor body, is the least of its priorities.

Unless, of course, the overriding demands of story call for a Concord, a Saratoga, a Yorktown. In that case, have at it.

From Rocketpunk Manifesto: THE SPACE AUTHORITY AND THE ORBITAL PATROL by Rick Robinson (2015)

Breeches Buoy

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Orbit Guard Ships


With the advent of lunar exploration and round trip lunar transport, both chemical and nuclear, there inevitably will arise malfunctions and emergencies. There will arise communication difficulties, navigational errors, propulsion breakdowns, and structural failures. There are possibilities of collisions between spacecraft and of fatal damage from matter in space. More likely, however, are onboard concerns of life-support malfunctions, auxiliary power irregularities, compartment over pressurization (in some cases, explosions), cargo shifting, and unforeseen disorders. These are the realities of increased space travel.

In anticipation of spaceflight realities, there would be need for a nuclear rescue ship operating in translunar space. The primary role of such a ship would be to save human life and those extraterrestrial specimens aboard any ill-fated lunar vehicle. A secondary role would be to salvage the spacecraft if at all possible.

This means that the rescue ship would require propulsive capability to drastically change orbit planes and altitudes. It would require excess ΔV to proceed with dispatch to rendezvous with a disabled spacecraft. In addition, capability would be required for transferring personnel and equipment, making repairs to a disabled vehicle, and even taking it in tow if conditions warranted. The latest advances in crew facilitation, passenger accommodations, repair shops, navigational devices, and communication equipment would be required. As an introductory concept, one arrangement of a nuclear rescue ship is presented in Figure 11-11 (see above).

A particular feature to note in Figure 11-11 is the use of two nuclear engines. Each engine would be of the lunar ferry vintage and, therefore, would be sufficiently well developed and man-rated for rescue ship design. These engines would be indexed by a nominal Isp of 1000 seconds; they would have a short time overrating of, perhaps 1100 seconds. This overrating implies conditional melting of nuclear fuel in the reactor for emergency maneuvers and dispatch.

A rescue ship would be characterized by a large inert weight compared to a regular transport vehicle. This means that large magnitudes of engine thrust would be required. However, during periods of non-emergencies, low thrusts could be used. The vehicle F/Wo characteristics (Thrust-to-weight ratio) would vary over a wide range: possibly from 0.1 during non-emergencies to 1 during emergencies. Two engines would provide the high thrust capacity for emergencies. During non-emergencies, one engine could be left idling; the other engine could provide low thrust for economic cruise. Furthermore, two engines would provide engine-out capability for take-home in the event of malfunction in one of the engines. For reactor control reasons, the two reactors would have to be neutronically isolated from each other. For this purpose, note the neutron isolation shield in Figure 11-11.

(ed note: Nuclear reactors are throttled by carefully controlling the amount of available neutrons within the reactor. A second reactor randomly spraying extra neutrons into the first reactor is therefore a Bad Thing. "Neutronically isolated" is a fancy way of saying "preventing uninvited neutrons from crashing the party." Related term is "Neutronic Decoupling")

A suggested patrol region for the rescue ship is indicated in Figure 11-12 (see above). Note that a rendezvous orbit has been designated so that the rescue ship could replenish its propellant from the nuclear lunar transport system. By having rendezvous missions with nuclear ferry routes, rescued personnel, lunar specimens, and damaged spacecraft parts could be returned to Earth without the need for the rescue ship returning. Also, rescue ship crew members could be duty-rotated this way. This would increase the on-station time of a nuclear rescue ship.

From NUCLEAR SPACE PROPULSION by Holmes F. Crouch (1965)
Orbital Patrol Ship
Exhaust Velocity4,400 m/s
Specific Impulse449 s
Thrust3.5×106 N
Thrust Power7.7 gigawatts
Total ΔV6,100 m/s
Mass Budget
Engine Mass7 mton
Heat Shield Mass15 mton
(15% re-entry mass)
Terra Recovery
parachute, retro,
landing gear
5 mton
(5% landing mass)
NonTerra Recov
landing legs
Luna, Mars
5 mton
(5% landing mass)
attitude jets,
electrical, etc.
20 mton
(20% dry mass)
farings, etc.
5 mton
(5% dry m)
Tankage body18 mton
(6% of
300 mton
hab module
cargo bays
25 mton
DRY MASS100 mton
300 mton
WET MASS400 mton
Mass Ratio4.0
booster rocket
? mton

This is a splendid spacecraft designed by Rick Robinson, appearing on his must-read blog Rocketpunk Manifesto. This was designed for his Orbital Patrol service, which he covered in three previous posts.

The important insight he noted was that if you can somehow get your spacecraft into orbit with a full load of fuel/propellant, it turns out that most cis-Lunar and Mars missions have delta V requirements well within the ability of weak chemical rockets. So you make a small chemical rocket and lob it into orbit with a huge booster rocket (heavy lift launch stack). This will be the standard Orbit Patrol ship.

It can also be boosted into orbit by a smaller booster rocket, then using the patrol ship's engines for the second stage. So as not to cut into the ship's mission delta V, it will need access to an orbital propellant depot to refuel. At a rough guess, you'll need 9,700 m/s delta V to boost the patrol ship into orbit (7,900 m/s orbital velocity plus gravity and aerodynamic drag losses). So the booster will need 9,700 m/s with a payload of 400 metric tons. Bonus points if the booster is reusable.

Actually, it reminds me a bit of the old Three Man Space Scout.

At a rough guess, Rick figures that if the ship is capsule shaped it will be about 12 meters high by 14 meters in diameter. If it is wedge shaped, it will be about 40 meters high by 25 meters wide by 8 meters deep.

In both cases, total interior volume of 1,200 m3 (of which 900 m3 is propellant), and a surface area of 800 m2

Present day expandable propellant tanks have a mass of about 6% of the mass of the liquid propellant. Rick is assuming that in the future the 6% figure will apply to reusable tanks as well.

If my slide rule is not lying to me, the 300 metric tons of H2-O2 fuel/propellant represents 33.3 metric tons of liquid hydrogen and 266.7 metric tons of liquid oxygen. About 470 m3 of liquid hydrogen volume (sphere with radius of 4.8 m) and 234 m3 of liquid oxygen volume (sphere with radius of 3.8 m). This is a total volume of 704 m3 which falls short of Rick's estimate of 900 m3 so I probably made a mistake somewhere.

Landing on Terra will use retro-rockets, the heat shield for aerocapture, maybe a parachute, and aircraft style landing gear for belly landing. Landing on Luna or Mars will be by tail-landing on rear mounted landing legs. That will also mean reserving some of the propellant for landing purposes.

Note that the heat shield is rated for the ship's unfueled mass (heat shield mass = 15% of ship's re-entry mass), there is not enough to brake the ship if it has propellant left. This assumes a "low-high'low" mission profile: start at LEO, go outward to perform mission while burning most of the propellant, then return to LEO or even land on Terra. So 15 metric tons for heat shield is for a ship with a mass of 100 metric tons at re-entry (ship's total dry mass).

If the ship is going to aerobrake then return to higher orbit, it will need more heat shield mass to handle the extra mass of get-home propellant. This will savagely cut into the payload mass, which is only 25 metric tons at best. For example, if the mission had the ship heading for translunar space from LEO after aerobraking, the extra propellant mass at aerobrake time will increase the heat shield mass from 15 metric tons to 31. This will reduce the payload from 25 metric tons to 8. But by the same token a ship that will not perform any aerobraking can omit the heat shield entirely, using the extra 15 metric tons for more propellant or payload.

Payload includes habitat module (if any) as well as cargo, since hab modules are optional for short missions. The gross payload is 25 metric tons, of which 20 is cargo and the other 5 mtons are payload bay structure and fittings. If you assume two tons of life support consumables per crew per two week mission; then the ship could carry a crew of five plus 12 mtons of removable payload, or a crew of 10 and 4 mtons of payload (the more that payload is consumables, the less mass needed for payload bay structure).

Patrol Missions
MissionDelta V
Low earth orbit (LEO) to geosynch and return5700 m/s powered
(plus 2500 m/s aerobraking)
LEO to lunar surface (one way)5500 m/s
(all powered)
LEO to lunar L4/L5 and return
4800 m/s powered
(plus 3200 m/s aerobraking)
LEO to low lunar orbit and return4600 m/s powered
(plus 3200 m/s aerobraking)
Geosynch to low lunar orbit and return
4200 m/s
(all powered)
Lunar orbit to lunar surface and return3200 m/s
(all powered)
LEO inclination change by 40 deg
5400 m/s
(all powered)
LEO to circle the Moon and return retrograde
3200 m/s powered
(plus 3200 m/s aerobraking)
Mars surface to Deimos (one way)6000 m/s
(all powered)
LEO to low Mars orbit (LMO) and return6100 m/s powered
(plus 5500 m/s aerobraking)

For a representative samples of small space craft atop booster rockets go here.

Space Garbage Collectors

All that junk in Terra orbit could trigger the dreaded Kessler Syndrome. If it happens, mankind might be cut off from space for generations. The Orbital Debris Collection agency is tasked with preventing that unhappy state of affairs.


The idea wasn’t without logic. The First Era of time travel had closely resembled the dawn of the space age in some ways—notably, in the trail of rubbish it left behind.

In the case of the space garbage, it had taken half a dozen major collisions to convince the early space authorities of the need to sweep circumterrestrial space clean of fifty years’ debris in the form of spent rocket casings, defunct telemetry gear, and derelict relay satellites long lost track of.

In the process they’d turned up a surprising number of odds and ends, including lumps of meteoric rock and iron, chondrites of clearly earthly origin, possibly volcanic, the mummified body of an astronaut lost on an early space walk, and a number of artifacts that the authorities of the day had scratched their heads over and finally written off as the equivalent of empty beer cans tossed out by visitors from out-system.

From DINOSAUR BEACH by Keith Laumer (1971)

Kessler Syndrome

The Kessler syndrome (aka Kessler Effect, Collisional Cascading, or Ablation Cascade) is where the number of pieces of orbiting space trash becomes so high that a single collision can start a chain reaction. A collision turns two pieces of trash into twenty. Most of those twenty new pieces will suffer collisions, now you have 400. When those hit you'll have 8,000. A couple of more collision cycles and LEO will basically become impassable. No more space launches, no more astronauts, no more GPS, no more communication satellites, no more space station.

If it actually happens space exploration and even the use of satellites could be rendered impossible for many generations. Egads.

The cascade may not spread to geostationary orbit, but that will just slightly delay matters. As those satellites wear out, they cannot be replaced.

A fictionalized version of this was depicted in the movie Gravity. It was exaggerated for dramatic effect, but not by much.

It was also used in the science fiction novels Planetes, Ejner Fulsang's SpaceCorp, Ken MacLeod's The Sky Road, and Max Brooks World War Z.

Note that this will probably be only an issue in Terra (or alien homeworld) orbit for hundreds of years to come. Other planets will need that long before enough trash collects in their orbit to become a problem.


The 2009 satellite collision was the first accidental hypervelocity collision between two intact artificial satellites in low Earth orbit. It occurred on February 10, 2009, 16:56 UTC, when Iridium 33 and Kosmos-2251 collided at a speed of 42,120 km/h (11.70 km/s; 26,170 mph) and an altitude of 789 kilometres (490 mi) above the Taymyr Peninsula in Siberia.


The collision destroyed both Iridium 33 (owned by Iridium Communications Inc.) and Kosmos 2251 (owned by the Russian Space Forces). The Iridium satellite was operational at the time of the collision. Kosmos-2251 was launched on June 16, 1993, and went out of service two years later, in 1995, according to Gen. Yakushin. It had no propulsion system, and was no longer actively controlled.

Several smaller collisions had occurred previously, during rendezvous attempts or the intentional destruction of a satellite, including the DART satellite colliding with MUBLCOM, and three collisions involving the manned Mir space station, during docking attempts by Progress M-24, Progress M-34, and Soyuz TM-17, but these were all low-velocity collisions. In 1996, the Cerise satellite collided with space debris. There have been eight known high-speed collisions in all, most of which were only noticed long after they occurred.


U.S. space agency NASA estimated that the satellite collision created approximately 1,000 pieces of debris larger than 10 centimeters (4 inches), in addition to many smaller ones. By July 2011, the U.S. Space Surveillance Network had cataloged over 2000 large debris fragments. NASA determined the risk to the International Space Station, which orbits about 430 kilometres (270 mi) below the collision course, to be low, as was any threat to the shuttle launch (STS-119) then planned for late February 2009. However, Chinese scientists have said that the debris does pose a threat to Chinese satellites in Sun-synchronous orbits, and the ISS did have to perform an avoidance maneuver due to collision debris in March 2011.

By December 2011, many pieces of debris were in a steady orbital decay towards Earth, and expected to burn up in the atmosphere within one or two years. By January 2014, 24% of the known debris had decayed. In 2016, Space News listed the collision as the fourth biggest fragmentation event in history, with Iridium 33 producing 628 pieces of cataloged debris, of which 364 pieces of tracked debris remain in orbit as of January 2016.

A small piece of Kosmos 2251 satellite debris safely passed by the International Space Station at 2:38 a.m. EDT, Saturday, March 24, 2012. As a precaution, the six crew members on board the orbiting complex took refuge inside the two docked Soyuz rendezvous spacecraft until the debris had passed.

A number of reports of phenomena in the US states of Texas, Kentucky, and New Mexico were attributed to debris from the collision in the days immediately following the first reports of the incident in 2009, although NASA and the United States Strategic Command, which tracks satellites and orbital debris, did not announce any reentries of debris at the time and reported that these phenomena were unrelated to the collision. On February 13, 2009, witnesses in Kentucky heard sonic booms. The National Weather Service issued an information statement alerting residents of sonic booms due to the falling satellite debris. The Federal Aviation Administration also released a notice warning pilots of the re-entering debris. Some reports include details that point to these phenomena being caused by a meteoroid shower. A very bright meteor over Texas on February 15, 2009, was mistaken for reentering debris.


Events where two satellites approach within several kilometers of each other occur numerous times each day. Sorting through the large number of potential collisions to identify those that are high risk presents a challenge. Precise, up-to-date information regarding current satellite positions is difficult to obtain. Calculations made by CelesTrak had expected these two satellites to miss by 584 meters.

Planning an avoidance maneuver with due consideration of the risk, the fuel consumption required for the maneuver, and its effects on the satellite's normal functioning can also be challenging. John Campbell of Iridium spoke at a June 2007 forum discussing these tradeoffs and the difficulty of handling all the notifications they were getting regarding close approaches, which numbered 400 per week (for approaches within 5 km) for the entire Iridium constellation. He estimated the risk of collision per conjunction as one in 50 million.

This collision and numerous near-misses have renewed calls for mandatory disposal of defunct satellites (typically by deorbiting them or at minimum sending them in graveyard orbit), but no such international law exists yet. Nevertheless, some countries have adopted such a law, such as France in December 2010. The United States Federal Communications Commission (FCC) requires all geostationary satellites launched after March 18, 2002, to commit to moving to a graveyard orbit at the end of their operational life.

From the Wikipedia entry for 2009 SATELLITE COLLISION




A prohibitive constraint on the use of conventional weapons in the anti-satellite (ASAT) role is their tendency to create debris through a variety of paths: direct ablation, spallation or fragmentation debris, warhead shrapnel, non-intercepting ordnance, and so forth.

The accumulation of such debris beyond a chaotically variable critical point – easily surpassed during military escalation, per Orbital Hazards in Simulated Great Power Escalation Scenarios (Oricalcios, Efiathe, and Cylassé, 2074) – poses a long-term hazard to civilization by inducing a cascade catastrophe, a rapid chain multiplication in debris count likely to render the orbital bands involved non-viable in the long term.

TAR BABY attempts to avert this by developing a specialized non-fragmentation ASAT weapon.

Specifically, we propose a dedicated ASAT warhead designed for compatibility with the Firehawk surface-to-orbit missile system (selected for its multiple-burn capability). Upon closing with the target satellite, this warhead deploys a sphere of viscous adhesive at its nose, formulated to remain effective in vacuum conditions for the duration of the impact event and to retain its shape via surface tension.

It is believed that this mechanism should allow a TAR BABY warhead to achieve a hard connect with the target satellite with minimal uncaptured fragmentation. Embedding within the adhesive body should in itself cause significant disruption to the operation of the target, but for maximal effect, after the adhesive sphere has set (either by passage of time or injection of a catalyst), the multiple-burn capability of the Firehawk can be used to perform a controlled deorbit and destruction of the captured satellite.

For further details of our proposal, please see the enclosed technical documentation.

Submitted for your consideration,

Vidal Amnestrianos

for and on behalf of

Firefly Aerospace, ICC

From Alistair Young (2019)


(ed note: the following is real)

1978—NASA Scientist, Donald Kessler, predicts that the density of space junk in Low Earth Orbit or LEO will eventually reach a critical mass such that the random collision rate will exceed the orbital decay rate—not unlike a nuclear chain reaction. Objects in LEO maintain orbital speeds of over 26,000 kilometers/hour, enough kinetic energy for a 1-kg piece of debris to destroy a 1000-kg satellite costing hundreds of millions of dollars. Such a collision would shatter the satellite into hundreds more fragments that go on to strike still more targets. If this phenomenon is unmitigated, the collision rate will hit a tipping point, exponentially reducing the life expectancy of new satellites until space is no longer be commercially viable.

1985—US F-15A fighter shoots down a 907-kg Solwind P78-1 research satellite with an antisatellite (ASAT) missile producing an undisclosed quantity of debris.

2006—USS Lake Erie Ticonderoga class missile cruiser shoots down USA-193 spy satellite with a RIM-161 Standard Missile 3 producing an undisclosed quantity of debris.

2007—Chinese Xichang Satellite Launch Center shoots down a 750-kg Fengyun FY-1C weather satellite with an SC-19 ASAT producing more than 3000 pieces of space debris.

2009—A 560-kg Iridium-33 communications satellite and a 950-kg Kosmos-2251 communications satellite collided producing a combined total of 1788 pieces of space debris.

2013—Chinese Xichang Satellite Launch Center tested an improved SC-19 ASAT missile capable of reaching medium earth orbit (MEO), highly elliptical orbit (HEO), and geostationary Earth orbit (GEO). There are no satellites orbiting Earth that are not vulnerable to ASAT attack.

(ed note: from this point on it is science fiction)

2022—NORAD publicly announces that without increased funding from Congress and the exponential increase in fragmentation and mission-related debris, it will in the future only attempt to track large spacecraft and rocket bodies.

2023US Congress passes a bill stating that the role of NASA is as a risk-reduction agency for the commercialization of space, citing there is no further public demand for space exploration. Included in the bill is authorization to sell to private interests all NASA and Air Force facilities and equipment devoted to space launch, development, and science & exploration.

2024—Nuclear weapons, now commonplace among Second and Third world nations, are primarily seen as political immunity devices due to the international consequences of offensive use of nuclear weapons—the return of the Cold War’s Mutually Assured Destruction doctrine (MAD). As a result, rogue nations turn to shooting down derelict satellites in LEO in order to advertise their status in the global arena.

2028—The average lifespan of a satellite is now less than three months due to increasing density of space debris. Lloyd’s of London declares it can no longer insure satellites. Commercial operations in LEO cease.

2030—SpaceCorp initiates construction of the SpaceCorp Space Station SSS Werhner Von Braun, a one kilometer spinning ring advertised as the first debris-proof instrument-hosting space station.

2038—The Von Braun is christened. 45 astronauts are killed and 427 wounded by debris strikes during its eight-year construction.

From SPACECORP by Ejner Fulsang (2014)

Orbital Debris Collection

Since the Kessler Syndrome could deny access to space for generations, it is logical to establish a (preferably multinational) organization charged with cleaning up orbital debris. But never underestimate the power of human stupidity.

Since politicians in general care little for anything happening beyond the next election cycle, they probably have little appetite for the money and poltical capital which must be spent to establish such an organization. Much like Spaceguard, actually. Action will probably be triggered by a close call or two.

And much like the manga Planetes the members of the serivce will be denigrated as "janitors" and "trash collectors".

Maybe after a partial Kessler the people (and corporations who suffer savage losses to their quarterly profits) will wake up and push for an orbital debris collection agency with teeth. Nations who recklessly launch rockets into risky trajectories will be hit with punishing sanctions. Or hit with an ODC commando team capturing the launch facilities.

And terrorists attempting to initiate a Kessler event will be a top-priority item with the counter-terrorism agencies of the world's nations. Classification: Hostis humani generis (Latin for "enemy of mankind"). Planetes had the The Space Defense Front, a terrorist organization that believes mankind is exploiting space without first curing global problems such as mass famine and the widened socio-economic divide on Earth.


      Derelict satellites could in future be grappled and removed from key orbits around Earth with a space tug using magnetic forces.
     This same magnetic attraction or repulsion is also being considered as a safe method for multiple satellites to maintain close formations in space.
     Such satellite swarms are being considered for future astronomy or Earth-observing missions – if their relative positions can stay stable they could act as a single giant telescope.
     To combat space debris, interest is growing in plucking entire satellites from space. The biggest challenge is to grapple and secure such uncontrolled, rapidly tumbling objects, typically of several tonnes.
     Multiple techniques are being investigated, including robotic arms, nets and harpoons.

     Now researcher Emilien Fabacher of the Institut Supérieur de l'Aéronautique et de l’Espace, part of the University of Toulouse in France, has added another method to the list: magnetic grappling.
     “With a satellite you want to deorbit, it’s much better if you can stay at a safe distance, without needing to come into direct contact and risking damage to both chaser and target satellites,” explains Emilien.
     “So the idea I’m investigating is to apply magnetic forces either to attract or repel the target satellite, to shift its orbit or deorbit it entirely.”
     Such target satellites would not need to be specially equipped in advance. Instead, such a tug would influence target satellites using their ‘magnetorquers’: reliable electromagnets already carried to adjust orientation using Earth’s magnetic field.
     “These are standard issue aboard many low-orbiting satellites,” adds Emilien. 
     The strong magnetic field required by the chaser satellite would be generated using superconducting wires cooled to cryogenic temperatures.

     Similarly satellites could also keep multiple satellites flying in precise formation, comments Finn Ankersen, an ESA expert in rendezvous and docking, formation flight.
     “This kind of contactless magnetic influence would work from about 10–15 m out, offering positioning precision within 10 cm with attitude precision 1–2°.”
     For his PhD research, Emilien has been researching how the resulting guidance, navigation and control techniques would work in practice, combining a rendezvous simulator with magnetic interaction models, while also taking account of the ever-changing state of Earth’s own magnetosphere.
     His research has been supported through ESA’s Networking/Partnering Initiative, which supports work carried out by universities and research institutes on advanced technologies with potential space applications. Emilien also visited ESA’s technical centre in the Netherlands, to consult with Agency experts.
     Emilien recalls that the concept originally came out of discussion with ESA experts, and he was lucky enough to be in the right place at the right time to explore its feasibility: “The first surprise was that it was indeed possible, theoretically – initially we couldn’t be sure, but it turns out that the physics works fine.”


When it comes to space debris, the numbers are repeated often: more than 21,000 objects ten centimeters across or larger, approximately half a million objects between one and ten centimeters in diameter. Across the space community, there is general agreement that space debris is an existing, and worsening, problem. Many point to the free and open access to space, while others argue that proposed “megaconstellations” will take low Earth orbit to the breaking point. In response, some argue that economic disincentives, like orbit fees or taxes, could be used to reduce demand by increasing the cost of a satellite in orbit. Some argue that additional satellites create additional debris risk solely based on the increase in the satellite population. But is this the problem we are trying to solve?

The problem of space debris and congestion is not one of operational satellites, but rather one created by non-maneuverable debris. Space situational awareness and conjunction alerting systems seek to prevent collisions by maneuverable objects, further reducing the risk they impose. It is not the operational satellite, but the behaviors associated with putting the satellite in orbit and removing it at end of life, that increases the debris risk.

In developing appropriate mitigation strategies for orbital debris, it is imperative to consider the primary causes of orbital debris and develop approaches that address those causes. The principal sources of orbital debris are satellite explosions and collisions, including intentional destruction. High-risk orbital behaviors are well known: old launch vehicle upper stages left in orbit with residual propellants and high-pressure fluids, defunct satellites that are not deorbited, and anti-satellite weapons testing. These are the primary contributors to orbital debris and should be the focus of debris mitigation strategies.

State, commercial, and non-government users of space have a shared interest in creating the long-term sustainability of space operations, and global progress requires international agreement. Proposers for an orbital use tax mention that it would need to be globally harmonized but fail to recognize the difficulty in reaching such an agreement—if such an agreement is even possible. The recent collapse of the OPEC pact and the subsequent oil price war illustrates the fragility of international economic collaboration. By contrast, international agreements on standards and regulation for international operators, as we see in the maritime and aviation industries, tend to endure. It is important to recognize that diplomatic resources are limited and efforts to reach international agreement should focus on areas that can provide the most benefit and have the greatest chance for success.

For the long-term sustainability of space, the answer is not to make space more expensive to use, but rather to ask the users, both civilian and military, to be responsible to the goal of sustainable use. This requires a focus in three critical areas: collision avoidance, limiting debris-generating behaviors, and debris removal. As we ask the space community to be more responsible, it is important to define what that means. As illustrated by recent anti-satellite missile tests, the community can be alarmed, but we are functionally unable to hold each other to standards of behavior if those standards do not exist. Efforts at international agreement should be focused on reaching agreement in these areas if we are to have a sustainable and accountable orbital domain.

The space debris problem is complex and will not be solved by targeting one section of the industry. It is important to look at primary contributors to the problem. Leaving non-maneuverable objects in orbit creates an unresolvable collision risk as illustrated in January, when two intact satellites that had been in orbit for decades came within meters of colliding (see “Will we hit the snooze button on an orbital debris wakeup call?”, The Space Review, February 17, 2020). By contrast, days before the potential collision, a damaged DirecTV satellite at risk of exploding was maneuvered to a graveyard orbit where it did not pose a debris hazard to other operators. An orbital use tax would put an additional financial penalty on the user that is able to prevent the collision risk but do nothing to change the behavior that created the collision risk. The orbital fees not only don’t solve the problem but, by and large, they are asking the commercial sector to pay for the pollution that was created by legacy users who were largely governments.

While economic incentives can be an effective tool to affect behavior, it is important that there is a clear connection between the economic lever and the behavior that it seeks to influence.


The Earth is surrounded by human-made orbital debris in all shapes and sizes that includes everything from abandoned satellites and leftover rocket stages to the tiniest paint chips and droplets from spacecraft coolant systems.

The hazard is very much real. Given the ultra-fast speeds of objects in space (satellites in low-Earth orbit fly at 17,400 mph), even the most minuscule bit of rubbish could create havoc if it crashed into a functioning  spacecraft.

The question of how best to de-clutter outer space has produced a wealth of proposals: some whacky, whimsical or wanting of a sanity check. Many space junk clean-up ideas have already been proposed, including: catch-all space sweepers, fishing nets and harpoons, tethers, laser blasts, big and small space tugs.

One of the latest looks at the orbital debris quandary was completed by the Defense Advanced Research Projects Agency (DARPA).

Released with little fanfare a few months ago, it was dubbed "The Catcher’s Mitt Study" – to assess the debris problem and its future growth, determine where the greatest problem will be for U.S. assets and then, if appropriate, explore technically and economically feasible solutions for debris removal. [Worst Space Debris Events of All Time]

Operation: Catcher’s Mitt

The report explains that active debris removal was found to be required at some point to maintain an "acceptable level" of operational risk.

"Although projections show that it may take decades for the risk to become unbearable," there are several reasons to begin development of a solution today, the Catcher's Mitt study states.

A central finding of the study is that the development of debris removal solutions should concentrate on pre-emptive removal of large debris in both low-Earth orbit (LEO) a few hundred miles above the planet, as well as geosynchronous Earth orbit (GEO), the realm of communications satellites and other key spacecraft about 22,400 miles (36,000 kilometers) up.

More a warning than background to the vexing dilemma of orbital debris, the Catcher's Mitt study explains that "failure to address this problem has significant implications for the success of future space missions due to the potential increased number of on-orbit collisions with non-trackable, yet lethal, debris fragments."

Significant, but manageable

Although space debris is a growing concern and will have to be addressed at some point in the future, even in the most congested low-Earth orbit altitude regimes, the current risk from orbital debris is significant … but manageable, said Wade Pulliam, manager of Advanced Concepts of Logos Technologies in Arlington, Va., and the former program manager of DARPA’s Catcher's Mitt report.

"By significant I mean that it can be one of the top single contributors to the lifecycle risk of a satellite, but manageable in that the risk is still sufficiently low that it doesn't require a change in operations," Pulliam told 

Pulliam noted that a recent study by The Aerospace Corporation projected the effects of the future debris environment over the next 30 years. It showed that for typical low-Earth orbit satellite constellations, the risk of space debris will add only 4 to 15 percent to the cost of the constellation, depending on the type of constellation.

"Of course, debris risk is statistical, so there may not be any problem at all or a collision will take out a satellite requiring a spare to be built and launched," Pulliam said. Still, a new significant debris event could statistically happen tomorrow which would greatly accelerate the growing risk and require a more immediate response, he cautioned.

Tragedy of the commons

In the big picture, Pulliam said that he considers orbital debris a human-made environmental problem.

"Although space is not an ecosystem per se, the problem is dependent on the cumulative effects of human activity over and above the ability of the nature system to balance like any other environmental challenge," Pulliam said.

Additionally, Pulliam advised that the constraints on finding an agreeable, cost-effective solution are remarkably similar to other current environmental issues. Specifically, the orbital debris problem can be characterized as a "tragedy of the commons."

The problem can also be explained by what is called "common but differentiated responsibility," which is also seen in other worldwide environmental challenges such as chlorofluorocarbons (CFCs) and global warming, Pulliam pointed out.

"It is likely new space-faring nations will make a similar argument if current mitigations efforts prove to be insufficient to forestall the deterioration of the low-Earth orbit environment and an international agreement on debris removal is required," Pulliam advised.

There is a "therefore" to Pulliam's view: That is, if you are one that believes that debris has become a risk which will soon make operations difficult in low-Earth orbit, then a top-priority has to be in continued research into cost-effective methods to remove debris mass already in orbit. That's because this mass is what will cause the future growth in the debris population. 

"There are many approaches that have been postulated for debris removal, but determining which are the most cost effective and demonstrating their utility is necessary to formulating a response to the overall problem with the lowest cost and risk," Pulliam said.

Up in the air

One lingering question that remains — putting think tank studies aside —is exactly who is in charge of orbital debris cleanup?

In the United States, the initial lead for Department of Defense (DoD) efforts regarding debris removal as called for in the new U.S. National Space Policy is reportedly the Office of the Secretary of Defense.

But still up for grabs (like space junk itself) is the delegation of the task to a particular organization within DoD. For example: the U.S. Air Force Research Laboratory; the Space and Missile Systems Center; or perhaps the Naval Research Laboratory.

"I think that the DARPA's Catcher's Mitt study clearly said that going after large, trackable, derelict debris is the most likely best recourse for debris cleanup," said Darren McKnight, technical director at Integrity Applications Incorporated in Chantilly, Va. "However, the best means to remove the large derelict objects is very much up in the air."

If history is any indication of the future, "the first large derelict debris removal action will most likely occur with a complicated, expensive rendezvous, grapple and move with a traditional propulsion system … though this approach will not scale well for the multiple objects that will likely have to be removed over the next few decades," McKnight told

The price of delaying action

McKnight likens the orbital debris situation today to the observations of Nassim Taleb, author of "The Black Swan - The Impact of the Highly Improbable." The book describes the difficulty of dealing with highly improbable and highly unpredictable events that have severe repercussions.

Taleb accentuates the plight for those who try to prevent "Black Swans" because they are never appreciated if they are successful, since preventing something that was highly unlikely to begin with does not bring acclaim. Often, it is quite to the contrary; they actually get ridiculed for their attempts to prevent events that others have difficulty even imagining.

"I hope that we do not have such a situation with active debris removal actions. While the calculus of delaying action is much clearer, it will still require some vision from policymakers and technologists to act now to start real programs for active debris removal," McKnight said. "Nobody has won the Nobel Prize for preventing a disaster that never occurred."


At 16:56 UTC on August 29, 2009, an Iridium communications satellite suddenly fell silent. In the hours that followed, the U.S. Space Surveillance Network reported that it was tracking two large clouds of debris—one from the Iridium and another from a defunct Russian military satellite called Cosmos 2251.

The debris was the result of a high-speed collision, the first time this is known to have happened between orbiting satellites. The impact created over 1,000 fragments greater than 10 centimeters in size and a much larger number of smaller pieces. This debris spread out around the planet in a deadly cloud.

Space debris is a pressing problem for Earth-orbiting spacecraft, and it could get significantly worse. When the density of space debris reaches a certain threshold, analysts predict that the fragmentation caused by collisions will trigger a runaway chain reaction that will fill the skies with ever increasing numbers of fragments. By some estimates that process could already be underway.

An obvious solution is to find a way to remove this debris. One option is to zap the larger pieces with a laser, vaporizing them in parts and causing the leftovers to deorbit. However, smaller pieces of debris cannot be dealt with in this way because they are difficult to locate and track.

Another option is send up a spacecraft capable of mopping up debris with a net or some other capture process. But these missions are severely limited by the amount of fuel they can carry.

Today, Lei Lan and pals from Tsinghua University in Beijing, China, propose a different solution. Their idea is to build an engine that converts space debris into propellant and so can maneuver itself almost indefinitely as it mops up the junk.

Their idea is simple in principle. At a high enough temperature, any element can be turned into a plasma of positive ions and electrons. This can be used as a propellant by accelerating it through an electric field.

The details are complex, however. In particular, the task of turning debris into a usable plasma is not entirely straightforward.

Lei and co focus their efforts on debris that is smaller than 10 centimeters in size, the stuff that laser ablation cannot tackle. Their idea is to capture the debris using a net and then transfer it to a ball mill. This is a rotating cylinder partially filled with abrasion-resistant balls that grind the debris into powder.

This powder is heated and fed into a system that separates positively charged ions from negatively charged electrons. The positive ions then pass into a powerful electric field that accelerates them to high energy, generating thrust as they are expelled as exhaust. The electrons are also expelled to keep the spacecraft electrically neutral.

Of course, the actual thrust this produces depends on the density of debris, the nature of the powder it produces, on the size of the positive ions, and so on. All this is hard to gauge.

And while the spacecraft does not need to carry propellant, it will need a source of power. Just where this will come from isn’t clear. Lei and co say that solar and nuclear power will suffice but do not address the serious concerns that any nuclear-powered spacecraft in Earth orbit will generate.

Nevertheless, the work provides food for thought. Space debris is an issue that looks likely to get significantly worse in the near future. It is an area where new ideas are desperately needed before the next big collision fills Earth’s orbits with even more debris.

(ed note: for more details, see: )

Ref: : Debris Engine: A Potential Thruster for Space Debris Removal


     Faced with the challenge of capturing tumbling satellites to clear key orbits, ESA is considering turning to an ancient terrestrial technology: the harpoon.
     Used since the Stone Age, first to spear fish and later to catch whales, the humble harpoon is being looked at for snagging derelict space hardware.
     Decades of launches have left Earth surrounded by a halo of space junk: more than 17 000 trackable objects larger than a coffee cup, threatening working missions with catastrophic collision. Even a 1 cm nut could slam into a valuable satellite with the force of a hand grenade.
     The only way to control the debris cloud across crucial lower orbits — like those that allow observation satellites to go on monitoring our planet at the same local time of day — is to remove large items such as derelict satellites and rocket upper stages.
     These uncontrolled multitonne objects are time bombs: sooner or later they will be involved in a collision. That is, if they don’t explode earlier due to leftover fuel or partially charged batteries heated up by sunlight.
      The resulting debris clouds would make these vital orbits much more hazardous and expensive to use, and follow-on collisions may eventually trigger a chain reaction of break-ups.
     To avoid this outcome, ESA’s Clean Space initiative is working on the e.DeOrbit mission for flight in 2021. Its sophisticated sensors and autonomous control will identify and home in on a target — potentially of several tonnes and tumbling uncontrollably.
     Then comes the challenge of capturing and securing it. Several different solutions have been considered, including a throw-net, clamping mechanisms, robotic arms — and a tethered harpoon.
     The harpoon concept has already undergone initial investigations by Airbus Defence and Space in Stevenage, UK.
     Harpoons rely on three physical actions to ensure safe and clean grasping: a high-energy impact into the target, piercing the structure and then reeling it in.
     A prototype harpoon was shot into representative satellite material to assess its penetration, its strength as the target is pulled close and the generation of additional fragments that might threaten the e.DeOrbit satellite.


laser broom is a proposed ground-based laser beam-powered propulsion system whose purpose is to sweep space debris out of the path of other artificial satellites such as the International Space Station. It would heat one side of an object enough to change its orbit and make it hit the atmosphere sooner.

Technical description

Lasers are designed to target debris between one and ten centimeters in diameter. Collisions with such debris are commonly of such high velocity that considerable damage and numerous secondary fragments are the result. The laser broom is intended to be used at high enough power to penetrate through the atmosphere with enough remaining power to ablate material from the target. The ablating material imparts a small thrust that lowers its orbital perigee into the upper atmosphere, thereby increasing drag so that its remaining orbital life is short. The laser would operate in pulsed mode to avoid self-shielding of the target by the ablated plasma. The power levels of lasers in this concept are well below the power levels in concepts for more rapidly effective anti-satellite weapons.

NASA research in 2011 indicated that firing a laser beam at a piece of space junk could alter velocity by 0.04 inches (1.0 mm) per second. Persisting with these small velocity changes for a few hours per day could alter its course by 650 feet (200 m) per day. While not causing the junk to reenter, this could maneuver it to avoid a collision.

Other funded research into this area refutes NASA's claim and demonstrates the precise physics involved, which shows that space debris is re-entered regardless of the direction of laser illumination. Using a laser guide star and adaptive optics, a sufficiently large ground based laser (1 megajoule pulsed HF laser) can deorbit dozens of objects per day at reasonable cost. This work was summarized in an article in Wired Magazine.

From the Wikipedia entry for LASER BROOM

Spacer's Guild

In our current day and age, people are not allowed to pilot an aircraft without a pilot's license or certification. Obtaining a license involves written tests and passing a flying test. In the United States, pilots are certified, not licensed. The difference is that legally a certification can be revoked by administrative action, while a license can only be revoked by the judiciary system (translation: the Civilian Aviation Authority can revoke a pilot's certification for whatever reason it wants, while a driver's license can only be revoked in traffic court).

Types of aviation pilot certifications include Student, Sport, Recreational, Private, Commercial, Flight Instructor, and Airline Transport. These can also be futher broken down into Category (aircraft, glider, lighter-than-air, etc.), Class (single-engine, multi-engine, helicopter, etc.), and Type (turbojet-powered, high-performance, complex, high-altitude, etc.)

Since spacecraft are far more expensive and potentially destructive than aircraft, you can be sure that space pilot certification (a "space rating") will be much harder to get. Initially such certification will be unavailable outside of the military or civilian space agencies. Once the technology has matured you will start to see commercial certification. Much later the technology will become commonplace enough to allow sport and recreational spaceflight.

In science fiction, space pilots sometime merge into a sort of guild. As time goes by it often becomes more and more difficult to join the guild unless you have a powerful guildmember as a sponsor. Eventually the guild become hereditary, where you cannot join unless one of your parents are already guild members. If things get really out of hand the guild becomes an empire and you have a full fledged Thalassocracy on your hands.

There are some science fiction novels where the pilot is not just the pilot, but also somehow a vital part of a starship's faster-than-light propulsion. These are also commonly part of a spacer's guild. Almost all of these have the pilot using some species of mystical psionic power that cannot be reproduced in a machine because of Authorial Fiat. Examples include the guild from Frank Herbert's Dune novels, "Pushers" from Robet Sheckley's Specialist, Telesthetic women from Redmond Simonsen's StarForce Alpha Centauri wargame, and Psi Navigators of the Universe RPG.

Sometimes you see a more mild application of superior abilities in humans compared to machines, milder than the human actually being the FTL drive that is. This is usually an authors device to justify the existence of human pilots, instead of a boring driverless spacecraft run by a computer autopilot. Examples include the Mass Sensor (unusable by computers) in Larry Niven's The Borderland of Sol and the Temporal Imbalance Sensor in the computer game Quest of the Space Beagle.


(ed note: The two major powers are Earth and Mars. The Belters are the poor downtrodden workers exploited by both sides. The Belt supplies minerals mined from the asteroid belt. Unfortunatly, a couple of novels prior, the solar system was gifted with a faster-than-light system allowing easy access to 1,373 garden planets. This is good news for Earth, sad news for Mars, but catastrophic news for the Belters. Suddenly the entire Belter nation have no jobs.)

      A little less than an hour later, a soft chiming and a discrete rush of personal assistants and aides announced the actual meeting. Pa let herself be carried along with a growing sense of displacement. The meeting room was smaller than she’d expected, and arranged in a rough triangle. Avasarala, a thin-faced man in a formal jacket, and two men in military uniforms sat at one corner. The Martian prime minister—Emily Richards—sat at another with half a dozen people in suits fluttering around her like they were moths and she was an open flame. And at the third, Carlos Walker, Naomi Nagata, James Holden, and Michio herself.
     A second rank of chairs held dozens of people whose roles Michio didn't know. Senators. Businessmen. Bankers. Soldiers. It occurred to her that if she’d had a bomb, she could probably have crippled what was left of humanity's major governments by taking out this one room.
     “Well,” Avasarala said, her voice clear as a Klaxon, “l 'd like to start by thanking all of you again for being here. I’m not fond of this sh*t, but the optics are good. And we do have some things to discuss. I have a proposal…" She paused to tap a command into her hand terminal, and Michio’s chimed in response, as did everyone else’s in the room. "…a proposal about the architecture by which we try to unf*ck ourselves. It’s preliminary, but we have to start somewhere.”
     Michio opened the document. It was over a thousand pages long, with the first ten a tightly written table of contents with notations and subsections for every chapter. She felt a little wave of vertigo.
     "The overview looks like this,” Avasarala said. “We have a list of problems as long as our arms, but Captain Holden here thinks he’s come up with a way to use some of them to solve the others. Captain?"
     Holden, beside her, stood up, seemed to realize no one else was going to stand up to talk, and then shrugged and bulled forward with it. "The thing is the Free Navy wasn’t wrong. With all the new systems opened up, the economic niche that Belters have filled is going to go away. There are so many reserves on these planets that don’t require we bring our own air or generate our own gravity that the Belt is going to be outcompeted. And, no offense, the plan up to now has been versions of ‘sucks to be you.‘
     "There’s a significant population of the Belt that’s not going to be able to move down a gravity well. They’re just going to be forgotten. Left to die off. And since that’s not all that different from how Belters got treated before, it was easy for Inaros to find political backing. ”
     "I wouldn’t say that was the only thing that got him there,” Prime Minister Richards drawled. "Having a bunch of my ships helped him out. "
     The room chuckled.
     "But the thing is,” Holden said, "we've been going out there wrong. There's a traffic problem we didn't know about. Under the wrong conditions, it's not safe to go through the (faster-than-light) gates. Which we found out because a bunch of ships went missing. And if the plan is that just anyone who wants to go through the gates does so anytime they want to, more will go missing. There has to be someone regulating that. And, thanks to Naomi Nagata, we now know the load limit of the gate network."
     He paused and looked around, almost as if he was expecting applause before he went on.
     " So that's two problems. No niche for the Belt. The need for traffic control through the gates. Now add to that the fact that Earth, Mars—all of us really—have taken enough damage in the last few years that our infrastructure won’t carry us. We have maybe a year or two to really find ways to generate the food and clean water and clean air that we're all going to need. And we probably can't do that in our solar system unless just a lot more people die. We need a fast, efficient way to trade with the colony worlds for raw materials. So that's why I'm proposing an independent union with the sole and specific task of coordinating shipments through the gates. Most people who want to live on planets will just do that. But the Belt has a huge population of people who are specifically suited to life outside a gravity well. Moving supplies and people safely between solar systems is a new niche. And it's one we need filled quickly and efficiently. In the proposal, I called it the spacing guild, but I'm not married to that name.
     A gray-haired man sitting two rows behind Emily Richards cleared his throat and spoke. “You're proposing to turn the entire population of the Belt into a single transport company? "
     "Yes, into a network of ships, support stations, and other services necessary to move people and cargo between the gates," Holden said. "Keep in mind, they've got thirteen hundred and seventy-three solar systems to manage. There's going to be work. Well, thirteen hundred and seventy-two, really. Because of Laconia.”
     "And what do you propose to do about Laconia?" a woman behind Avasarala asked.
     "I don't know," Holden said. "I was just starting with this."
     Avasarala waved him to sit down, and reluctantly he did. Naomi shifted, murmured something in his ear, and Holden nodded.
     "The proposed structure of the union,” Avasarala said, "is fairly standard. Limited sovereignty in exchange for regulatory input from the major governing bodies, meaning Emily and whoever they elect once I'm out of this.”
     "Limited sovereignty?" Carlos Walker said.
     "Limited," Avasarala said. "Don't ask me to put out on the first date, Walker. I'm not that kind of girl. The union will, of course, need to have support from the Belt. The first union president will be taking on a huge job, but I think we can all agree that we have a unique opportunity for that. Someone well-known both among Belters and on the inner planets."

From BABYLON'S ASHES by "James S.A. Corey" (2016)
Sixth novel of The Expanse

(ed note: Young Max runs away from his idiot mother and new abusive step-father. All he has is the clothes on his back, his ID card, and the astrogation manuals from his late uncle Chet. He meets a hobo named Sam.)

      Max had to admit that he was tired, exhausted really, and Sam certainly knew more about these wrinkles than he did. Sam added, “Got a blanket in your bindle?”
     “No. Just a shirt … and some books.”
     “Books, eh? Read quite a bit myself, when I get a chance. May I see them?”
     Somewhat reluctantly Max got them out. Sam held them close to the fire and examined them. “Well, I’ll be a three-eyed Martian! Kid, do you know what you’ve got here?”
     “But you ought not to have these. You’re not a member of the Astrogators’ Guild.”
     “No, but my uncle was. He was on the first trip to Beta Hydrae,” he added proudly.
     “No foolin’!”
     “Sure as taxes.”
     “But you’ve never been in space yourself? No, of course not.”
     “But I’m going to be!” Max admitted something that he had never told anyone, his ambition to emulate his uncle and go out to the stars. Sam listened thoughtfully. When Max stopped, he said slowly, “So you want to be an astrogator?”
     “I certainly do.”
     Sam scratched his nose. “Look, kid, I don’t want to throw cold water, but you know how the world wags. Getting to be an astrogator is almost as difficult as getting into the Plumbers’ Guild. The soup is thin these days and there isn’t enough to go around. The guild won’t welcome you just because you are anxious to be apprenticed. Membership is hereditary, just like all the other high-pay guilds.”
     “But my uncle was a member.”
     “Your uncle isn’t your father.”
     “No, but a member who hasn’t any sons gets to nominate someone else. Uncle Chet explained it to me. He always told me he was going to register my nomination.”
     “And did he?”
     Max was silent. At the time his uncle had died he had been too young to know how to go about finding out. When his father had followed his uncle events had closed in on him—he had never checked up, subconsciously preferring to nurse the dream rather than test it. “I don’t know,” he said at last. “I’m going to the Mother Chapter at Earthport and find out.”
     “Hmmm—I wish you luck, kid.”

(ed note: Of course Sam waits until Max is sleeping, then steals the astrogation books and Max's ID card)

(Max eventually manages to arrive at the hall of the Astrogator's Guild. Author Heinlein implies that Terran society in general and the Astrogator's Guild in particular are decadent. He uses subtle cues like the presense of universal ID cards and the snooty entitled manner of the guild members.)

     Everything about the hall of the Mother Chapter was to Max’s eyes lavish, churchlike, and frightening. The great doors opened silently as he approached, dilating away into the walls. His feet made no sound on the tesselated floor. He started down the long, high foyer, wondering where he should go, when a firm voice stopped him. “May I help you, please?”
     He turned. A beautiful young lady with a severe manner held him with her eye. She was seated behind a desk. Max went up to her. “Uh, maybe you could tell me, Ma’am, who I ought to see. I don’t rightly know just …”
     “One moment. Your name, please?” Several minutes later she had wormed out of him the basic facts of his quest. “So far as I can see, you haven’t any status here and no excuse for appealing to the Guild.”
     “But I told you …”
     “Never mind. I’m going to put it up to the legal office.” She touched a button and a screen raised up on her desk; she spoke to it. “Mr. Hanson, can you spare a moment?”
     “Yes, Grace?”
     “There is a young man here who claims to be a legacy of the Guild. Will you talk with him?”
     The voice answered, “Look, Grace, you know the procedures. Get his address, send him on his way, and send his papers up for consideration.”
     She frowned and touched another control. Although Max could see that she continued to talk, no sound reached him. Then she nodded and the screen slid back into the desk. She touched another button and said, “Skeeter!”
     A page boy popped out of a door behind her and looked Max over with cold eyes. “Skeeter,” she went on, “take this visitor to Mr. Hanson.”
     The page sniffed. “Him?”
     “Him. And fasten your collar and spit out that gum.”

     Mr. Hanson listened to Max’s story and passed him on to his boss, the chief legal counsel, who listened to a third telling. That official then drummed his desk and made a call, using the silencing device the girl had used.
     He then said to Max, “You’re in luck, son. The Most Worthy High Secretary will grant you a few minutes of his time. Now when you go in, don’t sit down, remember to speak only when spoken to, and get out quickly when he indicates that the audience is ended.”

     The High Secretary’s office made the lavishness that had thus far filled Max’s eyes seem like austerity. The rug alone could have been swapped for the farm on which Max grew up. There was no communication equipment in evidence, no files, not even a desk. The High Secretary lounged back in a mammoth easy chair while a servant massaged his scalp. He raised his head as Max appeared and said, “Come in, son. Sit down there. What is your name?”
     “Maximilian Jones, sir.”

     They looked at each other. The Secretary saw a lanky youth who needed a haircut, a bath, and a change of clothes; Max saw a short, fat little man in a wrinkled uniform. His head seemed too big for him and Max could not make up his mind whether the eyes were kindly or cold.

     “And you are a nephew of Chester Arthur Jones?”
     “Yes, sir.”
     “I knew Brother Jones well. A fine mathematician.” The High Secretary went on, “I understand that you have had the misfortune to lose your government Citizen’s Identification. Carl.”
     He had not raised his voice but a young man appeared with the speed of a genie. “Yes, sir?”
     “Take this young man’s thumb print, call the Bureau of Identification—not here, but the main office at New Washington. My compliments to the Chief of Bureau and tell him that I would be pleased to have immediate identification while you hold the circuit.”

     The print was taken speedily; the man called Carl left. The High Secretary went on, “What was your purpose in coming here?” Diffidently Max explained that his uncle had told him that he intended to nominate him for apprenticeship in the guild.
     The man nodded. “So I understand. I am sorry to tell you, young fellow, that Brother Jones made no nomination.”
     Max had difficulty in taking in the simple statement. So much was his inner pride tied to his pride in his uncle’s profession, so much had he depended on his hope that his uncle had named him his professional heir, that he could not accept at once the verdict that he was nobody and nothing. He blurted out, “You’re sure? Did you look?”
     The masseur looked shocked but the High Secretary answered calmly, “The archives have been searched, not once, but twice. There is no possible doubt.” The High Secretary sat up, gestured slightly, and the servant disappeared. “I’m sorry.”
     “But he told me,” Max said stubbornly. “He said he was going to.”
     “Nevertheless he did not.” The man who had taken the thumb print came in and offered a memorandum to the High Secretary, who glanced at it and waved it away. “I’ve no doubt that he considered you. Nomination to our brotherhood involves a grave responsibility; it is not unusual for a childless brother to have his eye on a likely lad for a long time before deciding whether or not he measures up. For some reason your uncle did not name you.”
     Max was appalled by the humiliating theory that his beloved uncle might have found him unworthy. It could not be true—why, just the day before he died, he had said—he interrupted his thoughts to say, “Sir— I think I know what happened.”
     “Uncle Chester died suddenly. He meant to name me, but he didn’t get a chance. I’m sure of it.”
     “Possibly. Men have been known to fail to get their affairs in order before the last orbit. But I must assume that he knew what he was doing.”

     “That’s all, young man. No, don’t go away. I’ve been thinking about you today.” Max looked startled, the High Secretary smiled and continued, “You see, you are the second ‘Maximilian Jones’ who has come to us with this story.”
     “Huh indeed.” The guild executive reached into a pocket of his chair, pulled out some books and a card, handed them to Max, who stared unbelievingly.
     “Uncle Chet’s books!”
     “Yes. Another man, older than yourself, came here yesterday with your identification card and these books. He was less ambitious than you are,” he added dryly. “He was willing to settle for a rating less lofty than astrogator.” (Sam of course)
     “What happened?”
     “He left suddenly when we attempted to take his finger prints. I did not see him. But when you showed up today I began to wonder how long a procession of ‘Maximilian Jones’s’ would favor us. Better guard that card in the future—I fancy we have saved you a fine.”

     Max placed it in an inner pocket. “Thanks a lot, sir.” He started to put the books in his rucksack. The High Secretary gestured in denial.
     “No, no! Return the books, please.”
     “But Uncle Chet gave them to me.”
“Sorry. At most he loaned them to you—and he should not have done even that. The tools of our profession are never owned individually; they are loaned to each brother. Your uncle should have turned them in when he retired, but some of the brothers have a sentimental fondness for having them in their possession. Give them to me, please.”     Max still hesitated. “Come now,” the guildsman said reasonably. “It would not do for our professional secrets to be floating around loose, available to anyone. Even the hairdressers do not permit that. We have a high responsibility to the public. Only a member of this guild, trained, tested, sworn, and accepted, may lawfully be custodian of those manuals.”
     Max’s answer was barely audible. “I don’t see the harm. I’m not going to get to use them, it looks like.”
     “You don’t believe in anarchy, surely? Our whole society is founded on entrusting grave secrets only to those who are worthy. But don’t feel sad. Each brother, when he is issued his tools, deposits an earnest with the bursar. In my opinion, since you are the nearest relative of Brother Jones, we may properly repay the earnest to you for their return. Carl.”
     The young man appeared again. “The deposit monies, please.” Carl had the money with him—he seemed to earn his living by knowing what the High Secretary was about to want. Max found himself accepting an impressive sheaf of money, more than he had ever touched before, and the books were taken from him before he could think of another objection.
     It seemed time to leave, but he was motioned back to his chair. “Personally, I am sorry to disappoint you, but I am merely the servant of my brothers; I have no choice. However …” The High Secretary fitted his finger tips together. “Our brotherhood takes care of its own. There are funds at my disposal for such cases. How would you like to go into training?”
     “For the Guild?
     “No, no! We don’t grant brotherhood as charity. But for some respectable trade, metalsmith, or chef, or tailor—what you wish. Any occupation not hereditary. The brotherhood will sponsor you, pay your ‘prentice fee and, if you make good, lend you your contribution when you are sworn in.”
     Max knew he should accept gratefully. He was being offered an opportunity free that most of the swarming masses never got on any terms. But the cross-grained quirk in him that had caused him to spurn the stew that Sam had left behind made this generous offer stick in his craw. “Thanks just the same,” he answered in tones almost surly, “but I don’t rightly think I can take it.”

From STARMAN JONES by Robert Heinlein (1953)

The Spacing Guild is an organization in Frank Herbert's science fiction Dune universe. With its monopoly on interstellar travel and banking, the power of the Guild is balanced against that of the Padishah Emperor as well as of the assembled noble Houses of the Landsraad. Mutated Guild Navigators use the spice drug melange to successfully navigate "folded space" and safely guide enormous heighliner starships from planet to planet instantaneously. Essentially apolitical, the Guild is primarily concerned with the flow of commerce and preservation of the economy that supports them; although their ability to dictate the terms of and fees for all transport gives them influence in the political arena, they do not pursue political goals beyond their economic ones. It is noted in Dune (1965) that Houses of the Imperium may contract with the Guild to be removed "to a place of safety outside the System"; in the past, some Houses in danger of ruin or defeat have "become renegade Houses, taking family atomics and shields and fleeing beyond the Imperium". The Guild controls a "sanctuary planet" (or planets) known as Tupile intended for such "defeated Houses of the Imperium ... Location(s) known only to the Guild and maintained inviolate under the Guild Peace".

From the Wikipedia entry for SPACING GUILD
Local No. 176

Father amd daughter were standing in the private office of the president, owner and sole manager of the Kenton Space Enterprises. From this small, simply furnished room Simeon Kenton ruled an empire vaster by far than any of the mighty empires of old Earth. Rome, Assyria, England, Germany, Nippo-China, Australo-America had flung their tight webs over large portions of the Earth's surface—but Simeon Kenton's fleet spaceships fastened their flags in the spongy marshes of Venus, on the desolate wastes of Mars, on rocky asteroids and mighly Jupiter itself.

Technically it was merely a commercial empire, with ultimate sovereignty in the Interplanetary Commission whose seal of approval was necessary on all leaseholds, claims of ownership, mining rights, trade routes, cargoes, exploitations, wages and hours and condition of employment. Actually Simeon Kenton was the kingpin of the spaceways, with half a dozen smaller princelets competing with him for concessions, spheres of influence and business. In the old days, when Simeon was a young man coming up the hard way, there had been no Interplanetary Commission and everything went, much to Old Fireball's irascible satifaction. Not, that he was a tyrant, by any manner of means. He was a driver and a hard taskmaster to his men, admitting of no failure or excuse; but he was fair and quick to reward the worthy. lf he was feared and if every man in his employ trembled in his space boots at the sight of him, deep down there was the comforting feeling that Old Fireball knew what he was about, that he never let them down.

Simeon loved the exercise of power, a vast, benevolent paternalism with himself as the paterfamilias. As space became less of a thing unknown, and law and order took the place of the old scramble for new worlds, however, codes were established, spheres delimited and space law came into being. All this was much to Old Fireball 's tremendous disgust. He grumbled constantly of the good old days, when men were men and not members of the Interplanetary Union of Spacement, Blasters, Rocket Engineers, Wreckers and Cargo Handlers, Local No. 176.

From OLD FIREBALL by Nat Schachner (1941)

Space Militia

On Terra, there exist organizations called "Maritime militias". These are commercial merchant vessels that can be called in times of emergency into support roles. Meaning law enforcement, disaster relief, and quasi-military operations.

This would be attractive in the early years of human expansion into the solar system since no nation is going to like the idea of the insane construction and support expense of a purely military spacecraft. Especially since for the most part it will standing idle.

On Terra, though, many are troubled by China's maritime militia, aka "a covert naval fleet disguised as fishing boats, with plausible deniability." This may become even more of a problem when China expands into space.


While the United States currently has a significant advantage in commercial space ventures, China is catching up quickly.

Economic interests in space continue to rise. In 2016 the global space economy represented $329 billion, and 76 percent of the total was produced through commercial efforts. With some of the most lucrative endeavors like asteroid mining, space tourism, micro satellites, and space colonies still in the early stages of development and application, it’s no wonder economic projections estimate the space sector will grow to $2.7 trillion over the next three decades.

Nations’ militaries will continue to protect vital economic interests, and outer space will be no exception. But how will it happen? Will the United States see peer competitor militaries expand more aggressively into outer space? The answer lies in gray zone tactics and space militias.

The operational complexities of the space environment coupled with poorly defined international norms and laws will likely encourage U.S. adversaries to use gray zone tactics. Chinese maritime militias provide a likely model.

Maritime militias are merchant and commercial vessels that, when called upon, support roles similar to those found in law enforcement, disaster relief, and the military. Maritime militias are rather common around the world and often serve useful missions. There are also maritime militias, however, that do more than serve peacefully.

Aside from Vietnam, China’s maritime militia is the only such organization that routinely harasses law abiding foreign vessels, among other aggressive activities. For example, in 2012 Chinese maritime militias participated in China’s seizure of the Scarborough Shoal from the Philippines. In 2015, when the USS Lassen sailed by Subi Reef, China used maritime militias to communicate Chinese opposition. These militias have become increasingly professionalized while still maintaining an ambiguous civilian affiliation, and herein lies the problem. The civilian nature of these militias provides Beijing the ability to deny involvement while making any sort of response from the United States, or others, very difficult. Even worse still, the use of maritime militias in this way allows China to undermine international law and begin to set legal precedence in their favor. Given the proven success of this tactic, the United States should anticipate similar approaches via space militias.

Space militias could operate much in the same way maritime militias act currently. Space militias will be commercial (or at least appear to be commercial) spacecraft supporting commercial activities but when directed by their government will quickly adjust and adopt a more military or law enforcement like role. The United States should expect these space militias to defend territory, provide situational awareness, and even attack other spacecraft through a variety of anti-satellite systems, but instead of people, these commercial spacecraft will rely on automation and artificial intelligence for basic operations. Without human life at stake risk tolerance will surely increase.

The complex environment of space will make this tactic very appealing. The vast distances between asteroids, planets and orbits means communications, situational awareness, and replacing or reinforcing spacecraft will be time consuming. This environment provides ample reason for states unconcerned with the separation of civilian and military entities to employ commercial platforms to achieve military objectives in a well-integrated and organized way.

To the benefit of those who would employ the gray zone tactics described above, laws and norms about the commercial and military use of space remain unsettled. While the 1967 Outer Space Treaty prohibits claims of sovereignty over celestial bodies, it doesn’t say anything about owning the resources extracted from said bodies. The treaty does require a nation-state to supervise its public or private organizations operating in space, but it doesn’t detail what constitutes adequate oversight. Outside the 1967 Outer Space Treaty, international space law is poorly defined and understood. Making matters worse, there isn’t any international organization designed to address commercial space activities. The lack of rules and regulatory bodies creates an ideal situation for space militias.

While the United States currently has a significant advantage in commercial space ventures, China is catching up quickly. Before China develops and normalizes the use space militias, the United States should pursue international agreements with partners nations that create clear laws, regulations, and norms that govern commercial activities in space. These agreements should not replace the 1967 Outer Space Treaty but, instead, supplement it. They should address commercial rights including definitions for demarcating claims and their operational zones, identification requirements differentiating civilian and military spacecraft and operations, and the creation of earth-bound organizations which serve as regulatory and legal forums for the creation of space customs and handling of space disputes. U.S. adversaries will deploy offensive military capabilities in space to defend their economic interest. The U.S. must proactively establish rules of the road before peer competitors gain the advantage by normalizing space militias.

The Patrol

The Patrol is sort of the space version of the police, coast guard, border patrol, pirate fighters, spacecraft safety inspectors, and customs agents.

There is no hard and fast division between the Orbit Guard and the Patrol. They sort of blur into each other. In some cases they might merge into one organization. The Orbit Guard is more biased to the civilian/search-and-rescue end of the spectrum, while the Patrol is biased more to the military/pirate-hunting end of the spectrum.

In the realm of science fiction, the Patrol was created by many authors. But the most well developed was in the space operas of Andre Norton. Norton's Patrol is right in the gray area between civilian and military, a combination of the police and the space navy. They appear in Star Rangers, the Jern Murdoc series, Star Hunter, and the Solar Queen series.

In James White's Sector General series, the Monitor Corps is strictly a police force, not a military one. White put it this way: if involved in a war situation the Monitor Corps are fighting to stop the war, rather than win it. To White, this is the difference between maintaining the peace and waging a war.

In the early days, at least, the Patrol may find itself performing small tasks that are not technically part of its charter. White's Monitor Corps is also in charge of interstellar survey, and first-contact work.

      I suspect the model will be something more akin to US Marshals or, better, the Canadian Royal Canadian Mounted Police. "RCMP in Space" is certainly fertile grounds for storytelling.
     It is not technically our job to deliver mail to Inuit villages above the arctic circle. But guess what? We're the only guys up here with a boat.

(ed note: or the only guys in this sector of the asteroid belt with a spacecraft)

by John Nowak

Related organizations are the Spaceguard, Laser Guard, and Santa Guard. These may be part of the Patrol, or totally separate agencies.

Yes, the Patrol will sometimes have to do naval boarding in the discharge of their duties.

Part of the Space Patrol's mission will involve checking out suspicious, rather than overtly hostile, activity, as with the present Coast Guard. If you know that Space Transport THX-1138 has been seized by Space Pirates (tm) who slaughtered the entire crew, you can lase it from a thousand kilometers away. If you're only guessing on the basis of some strange comm traffic, you've got to put a boarding party on the ship. If they are unarmed, you are only sending the pirates hostages.

From Dr. John Schilling

Evasion tactics? Easy enough. Axiomatically, it is impossible to stop a hostile ship in space. A cop can match course with a smuggler, but he cannot make an arrest unless the smuggler cooperates—or runs out of fuel. He can blow the ship out of space, or even ram with a good autopilot; but how can he connect airlocks with a ship that keeps firing its drive in random bursts? Brennan could head anywhere, and all the Outsider could do was follow or destroy him.

From PROTECTOR by Larry Niven (1973)


     THERE is an old legend concerning a Roman Emperor, who, to show his power, singled out the Tribune of a loyal legion and commanded that he march his men across Asia to the end of the world. And so a thousand men vanished into the hinterland of the largest continent, to be swallowed up for ever. On some unknown battlefield the last handful of survivors must have formed a square which was overwhelmed by a barbarian charge. And their eagle may have stood lonely and tarnished in a horsehide tent for a generation thereafter. But it may be guessed, by those who know of the pride of these men in their corps and tradition, that they did march east as long as one still remained on his feet.
     In 8054 A.D. history repeated itself — as it always does. The First Galactic Empire was breaking up. Dictators, Emperors, Consolidators wrested the rulership of their own or kindred solar systems from Central Control. Space pirates raised flags and recruited fleets to gorge on spoil plundered from this wreckage. It was a time in which only the ruthless could flourish.
     Here and there a man, or a group of men, tried vainly to dam the flood of disaster and disunion. And, notable among these last-ditch fighters who refused to throw aside their belief in the impartial rule of Central Control were the remnants of the Stellar Patrol, a law enforcement body whose authority had existed unchallenged for almost a thousand years. Perhaps it was because there was no longer any security to be found outside their own ranks that these men clung the closer to what seemed in the new age to be an out worn code of ethics and morals. And their stubborn loyalty to a vanished ideal was both exasperating and pitiful to the new rulers.
     Jorcam Dester, the last Control Agent of Deneb, who was nursing certain ambitions of his own, solved in the Roman manner the problem of ridding his sector of the Patrol He summoned the half dozen officers still commanding navigable ships and ordered them — under the seal of the Control — out into space, to locate (as he said) and re map forgotten galactic border systems no one had visited in at least four generations. He offered a vague promise to establish new bases from which the Patrol might rise again, invigorated and revived, to fight for the Control ideals. And, faithful to their very ancient trust, they upped-ship on this mission, undermanned, poorly supplied, without real hope, but determined to carry out orders to the last.
     One of these ships was the Vegan Scout — Starfire

     THE PATROL ship, Starfire, Vegan registry, came into her last port in the early morning. And she made a bad landing, for two of her eroded tubes blew just as the pilot tried to set her down on her fins. She had bounced then, bounced and buckled, and now she lay on her meteor-scarred side.

     “This system is far off our maps—very far removed from all the benefits of our civilization!”
     The benefits of Central Control civilization, yes. Kartr blinked as that struck home. His own planet, Ylene, had been burned off five years ago—during the Two-Sector Rebellion. And yet he sometimes still dreamed of taking the mail rocket back, of wearing his ranger uniform, proud with the Five Sector Bars and the Far Roving Star, of going up into the forest country—to a little village by the north sea. Burned off—! He had never been able to visualize boiled rock where that village had stood—or the dead cinder which was the present Ylene—a horrible monument to planetary war.

     “Go along and check the rest of the wreckage, fly-boy—”
     Fly-boy, eh? Well, the high and mighty senior service of the Patrol should be glad that the fly-boys were with them during this tour of duty. Rangers were trained to calculate and use the products of any strange world. After a crack up they would certainly be more at home in an alien wilderness than Patrol-crewmen.

     Because of the old division of the ship’s personnel—Patrol crew and rangers—Kartr did not know him very well.
     “You can easily accept the idea that we’re through,” the com-techneer was saying now. “You’ve never been tied to this hunk of metal the way we are. Your duty is on planets—not in space. The Starfire is a part of Vibor—he can’t just walk into the wide blue now and forget all about her. Neither can Jaksan.”
     “All right. I can believe that the ship might mean more to you, her regular crew, than she does to us,” agreed Kartr almost wearily. “But she’s a dead ship now and nothing any of us or all of us can do will make her ready to lift again. We’d best leave her—try to establish a base somewhere near food and water—”

     The rangers were not admitted to the inner circle of the Patrol—they were only tolerated. He was not a graduate of a sector academy, or even a product of the ranks. His father had not been Patrol before him. So he had always been aloof from the crew. The discipline of the Service, always strict, had been tightening more and more into a rigid caste system, even during the few years he had worn the Comet—perhaps because the Service itself had been cut off from the regular life of the average citizens.

     If Kartr felt alien in Patrol crews because he was not only a specialized ranger but also a barbarian from a frontier system, what must Fylh or Zinga feel—they who could not even claim the kinship of a common species?

     And Kartr knew that he must see too. As a ranger-explorer he had walked the soil of countless planets in myriad systems—nowadays he found it hard to reckon how many. There were some easy to remember, of course, because of their horror or their strange inhabitants. But the rest were only a maze of color and queer life in his mind and he had to refer to old reports and the ship’s log to recall facts. The thrill he had once known, when he pushed for the first time through alien vegetation, or tried to catch the mind waves of things he could not see, had long since gone. But now, as he scrabbled for a hand hold and dug the toes of his boots into hollows in the gritty rock, he began to recapture a faint trace of that forgotten emotion.

     The sled rode the air smoothly, purring gently. That last tune-up they had given her had done the trick after all. Even though they had had to work from instructions recorded on a ten-year-old repair manual tape. She had been given the last of the condensers. They had practically no spare parts left now—
     "Zinga," Kartr demanded suddenly of his seat mate. "Were you ever in a real Control fitting and repair port?"
     "No," replied the Zacathan cheerfully. "And I sometimes think that they are only stories invented for the amusement of the newly hatched. Since I was mustered into the service we have always done the best we could to make our own repairs—with what we could find or steal. Once we had a complete overhaul—it took us almost three months—we had two wrecked ships to strip for other parts. What a wealth of supplies! That was on Karbon, four—no, five space years ago. We still had a head mech-techneer in the crew then and he supervised the job. Fylh—what was his name?"
     "Ratan. He was a robot from Deneb II. We lost him the next year in an acid lake on a blue star world. He was very good with engines—being one himself."
     "What has been happening to Central Control—to us?" asked Kartr slowly. "Why don't we have proper equipment—supplies—new recruits?"
     "Breakdown," replied Fylh crisply. "Maybe Central Control is too big, covers too many worlds, spreads its authority too thin and too far. Or perhaps it is too old so that it loses hold. Look at the sector wars, the pull for power between sector chiefs. Don't you think that Central Control would stop that—if it could?"
     "But the Patrol—"
     Fylh trilled laughter. "Ah, yes, the Patrol. We are the stubborn survivals, the wrongheaded ones. We maintain that we, the Stellar Patrol, crewmen and rangers, still keep the peace and uphold galactic law. We fly here and there in ships which fall to pieces under us because there are no longer those with the knowledge and skill to repair them properly. We fight pirates and search forgotten skies—for what, I wonder? We obey commands given to us over the signature of the two Cs. We are fast becoming an anachronism, antiques still alive but better dead. And one by one we vanish from space. We should all be rounded up and set in some museum for the planet-bound to gawk at, objects with no reasonable function—"
     "What will happen to Central Control?" Kartr wondered and set his teeth as a lurch of the sled stabbed his arm against Zinga's tough ribs and jarred his wrist.
     "The galactic empire—this galactic empire," pronounced the Zacathan with a grin which told of his total disinterest in the matter, "is falling apart. Within five years we've lost touch with as many sectors, haven't we? C.C. is just a name now as far as its power runs. In another generation it may not even be remembered. We've had a long run—about three thousand years—and the seams are beginning to gap. Sector wars now—the result—chaos. We'll slip back fast—probably far back, maybe even into planet-tied barbarianism with space flight forgotten. Then we'll start all over again—"
     "Maybe," was Fylh's pessimistic reply. "But you and I, dear friend, will not be around to witness that new dawn—"
     Zinga nodded agreement. "Not that our absence will matter. We have found us a world to make the best of right here and now. How far off civilized maps are we?" he asked the sergeant.
     They had flashed maps on the viewing screen in the ship, maps noted on tapes so old that the dates on them seemed wildly preposterous, maps of suns and stars no voyager had visited in two, three, five generations, where Control had had no contact for half a thousand years. Kartr had studied those maps for weeks. And on none of them had he seen this system. They were too far out—too near the frontier of the galaxy. The map tape which had carried the record of this world—provided there had ever been one at all—must have rusted away past using, forgotten in some pigeonhole of Control archives generations ago.
     "Completely." He took a sort of sour pleasure in that answer.

     “Why don’t you just blast it?” demanded Snyn querulously. “All this stupid ‘don’t kill this—don’t kill that’! The thing’s only an animal after all—”
     “Shut up!” Smitt gave the crewman a slight push to set him going. “Don’t try to teach a ranger his business. Remember, if they hadn’t made contact with those purple jelly flying things we wouldn’t have come through the Greenie attack—those devils would have wiped us out without warning.

     Kartr studied him almost critically and then glanced down along the length of his own body. Their vlis hide boots and belts had survived without a scratch in spite of the rough life in the bush. And those blazing Comet badges were still gleaming on breast and helmet. Even if that Comet was modified by the crossed dart and leaf of a ranger it was the insignia of the Patrol. And he who wore it had authority to appear anywhere in the galaxy without question — in fact by rights the questions were his to ask.

From STAR RANGERS by Andre Norton, 1953.
Collected in STAR SOLDIERS (2001), currently a free eBook in the Baen free library.

(ed note: the boostship Agamemnon suffers a catastrophic failure to its engines {sabotage}, and the cargo tug Slingshot is chartered to go on a rescue mission)

      When we were fifty kilometers behind, I cut the engines to minimum power. I didn't dare shut them down entirely. The fusion power system has no difficulty with restarts, but the ion screens are fouled if they're cooled. Unless they're cleaned or replaced we can lose as much as half our thrust—and we were going to need every dyne.

     We could just make out Agamemnon with our telescope. She was too far away to let us see any details. We could see a bright spot of light approaching us, though: Captain Jason Ewert-James and two of his engineering officers. They were using one of Agamemnon's scooters.

     There wasn't anything larger aboard. It's not practical to carry lifeboats for the entire crew and passenger list, so they have none at all on the larger boostships. Earthside politicians are forever talking about "requiring" lifeboats on passenger-carrying ships, but they'll never do it.

     Even if they pass such laws, how could they enforce them? Earth has no cops in space. The U.S. and Soviet Air Forces keep a few ships, but not enough to make an effective police force even if anyone out here recognized their jurisdiction, which we don't.

     Captain Ewert-James was a typical ship captain. He'd formerly been with one of the big British-Swiss lines and had to transfer over to Pegasus when his ship was sold out from under him. The larger lines like younger skippers, which I think is a mistake, but they don't ask my advice.

From TINKER by Jerry Pournelle (1975)

Patrol Raison d'être

I wasn't sure how to logically justify the existance of an organization such as the Patrol, but Rob Garitta has a brilliant solution in his essay below:


My series of posts have tried to wake up merchants and other spacers to the colorful travellers and phenomena of the space lanes. Mind the colorful people are usually pirates and barbarians and the phenomena you could usually do without. Sorry, those are the thought that come to me out of the ether. I just get custody of them, as George Carlin once said (I'd love to say I wrote this during a lightning storm with a bottle of Scotch in my hand but alas it's a sunny day and I'm sipping iced tea.)

Anyway besides your basic pirates there's another group out there to worry about. They are every bit as relentless (maybe more), they have better technology, they have excellent crews. The Polity Navy takes a dim view of them many times. I refer to the Patrol (with a nod to Lady Andre Norton of course).

There is no branch called the Patrol in most Polities but it's there. Politics indicates a Polity will field fleets to prevent invasion, and rebellion. These fleets will have the most powerful ships and weapons available as well as the highest technology level.

These fleets will be idle and trying to look busy 99% of the time. It's that other 1% that you keep them around for: war, blockades, rebellions, invasions, and spitting on the GHU-Emperor's statue. For fighting pirates these fleets are almost 100% useless. In building big ships to serve as deterrents you are concentrating your forces. Fighting a group of pirates or a smuggling fleet with a fleet like this is much like taking a sledgehammer to a swarm of gnats. The pirates go where the big ships aren't. Big ships require a scheduled route for political and defense considerations. This may be the same thing. Fleet Day may come early if your Planetary Baron is feeling uppity. Pray they leave early too.

Add to this that a remote central government probably doesn't give a chinchilla's ass about your local concerns or the distress call of that lousy 200 ton free trader ... Roland, Siegfried? I forget the name.

After paying their share of taxes for the Polity fleet member worlds with any sort of leaderships will tighten their belts and pay another tax for their local fleet, usually referred to as the Patrol. Yes it is part of the Navy, much as some regard the Marines as part of the US Navy. You try telling a Marine that and I'll take pictures. Apart from a temporary alliance the Patrol and the Fleet do not work that closely. While the Fleet exists to protect the Polity, the Patrol takes care of things on a local level.

The frontier navy does not have the budget of the Fleet. Small ships are used with local technology that do not require special bases or technicians to maintain. Crew are small. There's no Marine equivalent, ship troops handle boarding actions. Ship's boats (30 dtons or average of 8.4 metric tons) are used extensively to augment firepower in a sort of mini-battlerider strategy. These ships are crucial in raiding pirate bases that traditionally have landing fields that are a nightmare for large ships.

The Patrol has relatively small ships (800 dtons {2,230 metric tons} and under and darned few 800 dton ships {warships are more like 300,000 metric tons}). They do try to be everywhere. They use technology locally available and are built for lengthy patrols. Finally the Patrol skipper has a high degree of autonomy. Beyond a few scheduled stopovers for various concerns a Patrol skipper has a group of star system they patrol in whatever fashion they choose, barring orders from above.

The autonomy part gives pirates the fits. The Fleet makes a show of arriving and leaving and goes for shock and awe. It's like a marching band. The Patrol shows up where and when you least expect it, much like the guy who steps on a subway train, starts playing a flute and passes the hat around.

There's a difference in culture as well. Navy officers (and crew where possible) will often be stationed in ships and fleets far from their homeworlds. Their first loyalties and interests are to the Polity, not some locals (barring shore leave.) The crew of the Patrol are the locals. The Fleet regards anti-piracy missions as search and destroy missions (usually against a base or a lone ship with phenomenally bad luck/judgement). The Patrol uses local contacts and local rumor mills to ferret out the informants and fences so necessary for successful pirate enterprises. There are even instances of one pirate ring informing on another group invading their territory to the Patrol. After all locals look out for each other.

The Parol is also relentless in mounting sting operations often using upgunned merchant ships or captured pirate vessels. These stings extend to Patrol crew operating undercover in starports to report suspicious goings on. Besides their own contacts and agents the Patrol cultivates good relations with the Scouts and the Free Traders. Both are valuable sources of information on local shipping. In the case of the traders some helpful tips might lead to the Patrol looking the other way when you have some duty free cargo in your hold.

The system is not perfect. For one thing in some areas the Patrol amounts to a private navy beholding only to its homeworld and little else. In Polities that are confederations local navies may be dominant. These look to their own world leaders and admiralty for orders first then the Polity. The central government usually takes a dim view of this and restricts ship size and armament when it can.

Even so Patrols are often scenes of power struggles as local commanders do not always cooperate with others in a cluster funded navy. It gets worse if one or more worlds rebels against the Polity. In the case of a rebellion the Patrol is usually the first to get the ax. The Polity Fleet will regard them as possibly disloyal and move to disarm them and intern their ships. Similarly some local planets may regard them as tainted by offworld contacts and interests and move to eliminate their officers at the very least.

In a final  sign that the Universe's most fundamental force is irony: many Patrol ships faced with their homeworld turning rebel, turn pirate.

From THE OTHER FLEET by Rob Garitta (2016)

      All traders know there will come a time when you are hailed, intercepted and boarded and you'd damned well better make the right decisions or risk getting your freighter shot to pieces, see your crew get shot to pieces and lose everything.

     The enemy has the weapons, has the troops, and the skill. They are the Patrol!


     The Fleet is the creation of a number of advanced and populated worlds. It exists to preserve the status quo, the fat freighter plying their way between major centers of commerce. They have the tax base to let them by the big ships, pay their crews the premium salaries and get the best and brightest. Any pirates operating in the core worlds better have a masterful plan, make their score and then go into cold sleep for a few hundred years.

     Out on the Frontier ... there is still commerce and trade (much of it legal). There are also pirates as always. The Frontier has the Patrol, armed well enough to raise merry Hell with one or more pirate ships. It's a smaller, leaner operation and it is chronically underfunded. The worlds that support it have less money, less of s pool of skilled crew. They need as many ships as possible to cover as many hot spots as possible. How do they pay for this?

     Asset forfeiture!

     The business model is simplicity itself. Most traders smuggle at least part of the time. Nearly everyone's smuggled at least once. Make a trader pull over and you have a decent chance of finding some swag. What then? The Patrol does not maintain extensive correctional facilities and most planetary governments don't want the refuse of space crowding out their native felons. The easiest ways to punish for nonviolent crimes is fining, suspending licenses, and exile.

     Under fines read confiscating your cargo (all of it) and maybe your ship for a serious enough smuggling offense. Knowing what goods are contraband or may be regarded as such on your port of cal is a big job. It's where your deckmasters pay for themselves several times over.

     For a big enough offense the entire ship may be forfeit. This rarely happens because one case of this can scare the free traders away for years. It is a great tool for starting up your own shipping line and keeping outsiders from competing with you. But then your trade efforts might still be hampered for some time. Other free traders may not want to support an organization that started out screwing their own.

     The Banks have a handy solution to the immense power of asset forfeiture the Patrol wields. In the case of a mortgaged ship being seized, only part of that ship belongs to the offending party. The rest belongs to the Bank and in such cases the Patrol gladly hands over the ship in exchange for a fraction of the principal already paid to the Bank. The Bank gets a ship back that it can mortgage again, the Patrol gets a fat check, and evildoers are punished. Sometimes Banks even let these ships go cheap since they are often used. there might be problems with former owners seeking to steal the ship for various reasons (hidden compartments, vital information encoded on the computer etc.)

     Please note in many cases the Bank turns right around and remortgages the ship to the same poor slob that it was confiscated from. Hey, crews don't grow on trees, every day that ship is sitting in a port it could be earning money for the shareholders. Besides, the so called lawbreakers already passed a background check once! So they broke a local law! It happens.

     Note that the Patrol could sell these confiscated ships and pay the rest of the principle in the mortgage, but seldom has the interest or networking to get a good price. Also the Banks pay taxes and wield a lot of clout in many local governments. You don't want to tick them off.

     Less extreme than asset forfeiture is the phenomenon of spot inspections. A bunch of Patrol inspectors boards you and finds your vessel to be a flying deathtrap. Stiff fines ensue! Or someone 'notes/ a leak of a vital commodity (fuel, propellant, air) just as it is vented explosively (did someone nudge a switch?). What a pity. The nice Patrol Captain is willing to sell your some more fuel or whatever at triple cost.

     All these dirty trick can be done by space port inspectors. They aren't done commonly because the Patrol usually gets to traders first and getting gouged by a Patrol ship is avoidable in theory, if they can't intercept. The way you avoid gouging on planet is avoiding that planet. Not good for business.

(ed note: This happens in an episode of The Expanse entitled "Rock Bottom." The gutter punk Diogo assists his bitter, cranky Uncle Mateo, a working-class 'rockhopper' who explores asteroids looking for precious ore in the rustbucket spaceship Xinglong.

They are intercepted by the MCRN Scipio Africanus, a Martian border patrol vessel. Mateo is busted for an expired transponder and ordered to impound his haul. This will leave Mateo bankrupt.

After the Scipio Africanus starts to leave, an enraged Mateo kicks his nephew off the Xinglong in an space suit, then goes on a suicide run on the Martian ship. Mateo uses his ship to hurl a deadly cloud of high velocity asteroid shrapnel at the Scipio Africanus, as an impromptu kinetic energy weapon. This kicks the war into high gear.)

From THE COST OF BUSINESS by Rob Garitta (2016)

      But the function of the Monitor Corps, the law enforcement and executive arm of the Galactic Federation whose sixty-odd intelligent species were represented on the staff of Sector General, was something that needed clarification, I thought. The result was a very long novelette of some 21,000 words.

     Essentially the Monitor Corps was a police force on an interstellar scale, but I did not want them to be the usual ruthless, routine-indoctrinated, basically stupid organization that is so handy to have around when an idealistic principal character needs a bit of ethical conflict. Conway was one of the good guys and I wanted them to be good guys too, but with different ideas as to the kind of activity that produces the greater good.

     Their duties included interstellar survey and first-contact work as well as maintaining the Federation’s peace—a job that could, if they were unable to discourage the warmongers, give rise to a police action that was indistinguishable from an act of war. But the Corps much preferred to wage psychological warfare aimed at discouraging planetary and interplanetary violence and when, despite their efforts, a war broke out, then they very closely monitored the beings who were waging it.

     These warlike entities belonged to a psychological rather than physiological classification, and regardless of species they were the classification responsible for most of the trouble within the Federation. The story told of the efforts of the Monitor Corps first to attempt to prevent the war and then damp down the war, and Conway and Sector General came into it only when things went catastrophically wrong and large numbers of human and e-t casualties had to be dealt with. The original title of the story was “Classification: Warrior.” (later changed to Occupation: Warrior)

     Normally I do not like stories of violence or the senseless killing that is war. But if a story is to hold the interest of the reader there must be conflict, which means violence or struggle of some kind. However, in a medical SF story of the Sector General type the violence is usually the direct or indirect result of a natural catastrophe, a disaster in space or an epidemic of some kind. And if there is a war situation of the kind that occurred in Star Surgeon, then the medics are fighting only to save lives, and the Monitor Corps, like the good little policemen they are, are fighting to stop the war rather than win it—which is the essential difference between maintaining the peace and waging a war.


      EARTH as such did not have a space navy; there was no danger of attack from space and, as far as Earth was concerned, the outplanets could take care of themselves. Nor did either WestHem or EastHem; with their ICBM's they did not need or want any subspace-going battleships. Nor did any of the planets. Newmars and Galmetia were heavily armed, but their armament was strictly defensive.

     Thus InStell (the Interstellar Corporation) had been forced, over the years, to develop a navy of its own, to protect its far-flung network of merchant traffic lines against piracy; which had of course moved into space along with the richly-laden merchantmen. As traffic increased, piracy increased; so protection had to increase, too. Thus, over the years and gradually, there came about a very peculiar situation:

     The only real navy in all the reaches of explored space—the only law-enforcement agency of all that space—was a private police force not responsible to any government!

     It hunted down and destroyed pirate ships in space. It sought out and destroyed pirate bases. Since no planetary court had jurisdiction, InStell set up a space-court, in which such few marauders as were captured alive were tried, convicted, and sentenced to death. For over a century there had been bitter criticism of these "highhanded tactics," particularly on Earth. However, InStell didn't like it, either—it was expensive. Wherefore, for the same hundred years or so, InStell had been trying to get rid of it; but no planet—particularly Earth—or no Planetary League or whatever—would take it over. Everybody wanted to run it, but nobody would pick up the tab. So InStell kept on being the only Law in space.

     This navy was small, numbering only a hundred capital ships; but each of those ships was an up-to-the-minute and terribly efficient engine of destruction, bristling with the most modern, most powerful weapons known to man.

From SUBSPACE EXPLORERS by E.E. "Doc" Smith (1965)

Patrol Ships


This leaves the question of what sort of vessel would be used as a light patrol craft in orbital space.  This might be best described as a cutter or a patrol boat, and would be intended for use in a friendly orbit with nearby basing facilities.  Each watch would have a crew of at least three — officer, sensors/weapons, and helm, though the number might rise higher for workload reasons.  Particularly if there are a significant number of vessels to monitor, multiple sensor operators might be required.  After 6 hours on watch, efficiency drops dramatically, so while a short-endurance vessel might get away with one shift and a microwave, a vessel designed for anything more than that will need multiple watches, some facilities for off-duty crew, and probably a mechanic or two.  (In most circumstances it would make more sense to place all of this on a customs base of some sort instead of on the cutter itself.)

Because the cutter will be called upon to perform boarding missions, the crew might well be outnumbered by the Espatiers detachment.  Weapons fit would be limited, probably to a medium laser for takedowns, and maybe an EMP generator (assuming such a weapon is practical).  Heavy kinetics are unlikely to be seen on patrol craft for reasons mentioned in Section 6, although surface-effect and precise unitary ones are potentially useful.  The drive is most likely to be nuclear-thermal, though chemfuel is possible, particularly for smaller craft.

At the low end of the boarding-craft spectrum, we have a one-shift vessel with a crew of three, incapable of true independent operation.  It’s dispatched to hunt down a specific target and deliver a squad or two of Espatiers.

At the high end is a vessel ("large cutter") that has a crew of a two dozen, can operate independently for a month or more, carries a full platoon of Espatiers, and can serve as a light warship if necessary.  A vessel of this size might carry a small, probably unarmed parasite intended to transport a squad of Espatiers over to a potentially hostile vessel.  It has been suggested that this sort of vessel might have a modular troop/weapons bay, allowing it to serve as a corvette as well as a cutter.  The biggest limit on its endurance is the lack of a spin hab, which would adversely affect the health of the onboard Espatiers.

All of this leads to the question of patrol outside one’s own orbital space.  The scenario in question is one that resembles more than anything else is that of the various naval detachments of the 19th century, such as the Asiatic Squadron and the China Station.  The objective is to protect the power’s interests, and those of their nationals engaged in commerce, in a relatively wild part of space.

Several people have suggested some form of “patrol carrier” or “space control ship”, as discussed in Section 1.  This would involve a single large ship with several parasites, and possibly significant weapons of its own.

The parasites would be responsible for a number of missions, and would likely be a modular system.  At the largest end are the drives which serve as the basis for manned missions.  Option probably include general shuttle (passengers and light cargo), boarding shuttle (espatiers and maybe a few weapons), gunboat/scout (light weapons) and heavy lancers (used to threaten someone into seeing things your way).  Smaller drives would be used for recon, light lancer, and other uses.  The exact numbers and capabilities of each are dependent on both technical and operational details outside the scope of this paper.

It has also been suggested that modularity could be extended to the patrol carrier itself.  The parasite bays could be swapped out for supplies, quarters, or even additional weapons as needed for the mission.

The drawback to the concept is that the owing power’s entire presence in the area is dependent on a single ship.  If the patrol carrier is damaged or destroyed, the parasites will likely be sitting ducks for an enemy.  On the other hand, the same could largely be said of US aircraft carriers today.

The patrol cruiser carrier is more likely to be used in large areas, such as a planetary moon system, where there are multiple powers and multiple potential issues simultaneously.

If the objective is to keep an eye on one specific power, it makes as much sense to simply keep a single “frigate” on station.  This frigate would resemble the large cutter described above, but with more weapons and the capability to support its crew for months at a time.

Another alternative for presence missions is to keep most of one’s forces centralized, ready to react to situations.  Some small presence ships would probably remain on station to handle minor issues, while centralization would theoretically allow savings in forces.  The biggest potential issue is the possibility that the smaller ships will be unable to handle problems that could be stopped by the bigger forces.  This also suffers from the problems mentioned below involving variable transit time.

One potential issue that this type of ship (or any ship on a distant station) suffers from is the fact that it is several weeks to several months away from help.  This means that if any problem develops, it will have to deal with it out of its own resources.  The obvious comparison is to the age of sail, but that analogy falls apart when one considers that communication lags will be hours long at most.  Not only that, travel times will vary significantly with orbital positions.  Anyone trying to make trouble, particularly someone planning a rebellion, would take that into consideration.  At the same time, their opponents would be able to see the same thing, and would probably step up security at times when help is furthest away.

Another issue for distant stations is supply and operations.  The problem is quite simply that even with high-Plausible Mid-Future (high-PMF) drive tech, shipping in all of the supplies required is incredibly expensive, and the operational issues are even worse.  Typical wet Navy cruises are six months or so (including port visits.  SSBNs, which are probably the best analogy for long-duration spacecraft, only stay out for 90 days) and transit time will be at least a month.  This in turn means that it will probably take at least 4 ships for every one that is forward-deployed.  The obvious solution to this is to home-base the ships at the area to be patrolled.  This in turn requires a local ally, making it only useful in balkanized territories.  Even the use of a semi-neutral power for supply is a dubious proposition.  They could be pressured to cut off your supplies, or someone could slip a nuclear weapon aboard a supply shuttle.

It has been suggested that pre-positioned fleets could be used as forward defense against a potential enemy invasion.  This falls afoul of three issues.  First, as described above, the supply problems are likely to be horrendous.  Any power that is strong enough to pose a potential invasion threat is likely to dominate the area to the extent that a friendly supply base is not available.  Second, said enemy will be able to easily overwhelm your forward-deployed forces (see the 4 to 1 ratio described above).  Thirdly, the legal issues with deploying forces in their Hill Sphere are likely to be significant.  It would be a far better plan to use InterPlanetary Ballistic Missiles (IPBMs) to wear them down as their fleet approached, and concentrate your forces to defeat whatever arrives.  The fact that the operational costs of the deployment are not incurred would also allow the purchase of more vessels, and a better force ratio at home.

Another suggestion for military patrols is the use of cyclers.  A cycler is a large space station launched into a specific orbit so that it passes by two planets repeatedly and at predictable intervals.   Due to orbital mechanics, they generally make a quick passage in one direction, and a slow one in the other.  The idea behind cyclers is that they avoid accelerating and decelerating lots of equipment that is used on every trip, such as life support and passenger quarters.  The cycler itself provides no aid in accelerating and decelerating the passengers/cargo during transfers.  The problem is that this only makes sense when delta-V is very expensive.  The low duty cycle of the cycler is a significant problem, as is the need for perfect rendezvous with it.  In most PMF settings, nuclear-electric drives would render them obsolete.

For military use, the cycler is even worse.  To quote Milo: “So wait, are you postulating large, poorly mobile weapons platforms that fly past planets on predictable courses at high speeds?”  The actual concept proposed was to use the cycler more as a base than as the weapon platform itself, but a number of issues remain.  The cycler is vulnerable in the extreme to kinetics, even unguided ones, and it has a very low ‘duty cycle’ with respect to its target, which means either extremely high costs, low visit rates, or weak patrols.  It also greatly simplifies the task of anyone planning mischief.  They know exactly when the patrol will arrive and how long it will stay.  It has been suggested that the cycler could take care of some of the housekeeping issues for the carried warships, but this is impractical in operation.  The ships would be unable to fight over long periods, and would have to leave when the cycler did, or be forced to stay until the next pass.

An alternative to cyclers is some form of ‘Mobile Base.’  This is quite similar to the proposed cycler, but instead of swinging by every few years, it moves to the area of interest and stays until the problem is solved.  This base carries extra remass, supplies, ammo, repair equipment, and probably R&R facilities for the crews.  It can afford to use lower-powered engines and less delta-V than a conventional warship, as it is only intended to deploy for serious crises which will occur over prolonged periods.  The combat vessels would arrive early and stay on station until the base got there, and then use it to remain operational.

by Byron Coffey (2019)

It was true that officers were not supposed to leave a ship while under way, but notwithstanding the regulations, Beckley saw no good reason for making them forego their daily exercise. The Pollux was swinging lazily in a wide orbit about the Jovian System, her electronic blasts cold and dark, patrolling for routine traffic-control purposes. Forbidding men to go over the side was as senseless a restriction as to prohibit swimming from an anchored ship.

He made his way to the boat deck, and as he stepped out of the air lock onto the broad fin he was impressed by the size of the huge vessel. Its hull sloped upward and away from him, gray in the dim light of a dwindled sun, and he saw for the first time the row of alcoves let into the ship’s side that sheltered the boats. Those, he knew, were used for the reconnaissance of asteroids or areas too rugged to put the ship down on, or for minor searches, or for rescue expeditions. Star-class cruisers, being designed for all-planet service, were equipped with vertical and horizontal fins to stabilize them when easing into an atmosphere, and the horizontal ones made ideal landing decks for their boats.

It fell to Fraser’s lot to conduct the Abandon Ship Drill. The Polliwogs were tense as televox repeaters throughout the ship chanted the call to the boats. Number 3, on the starboard side, was a balky sl*t. Five times out of six her tube would not fire unless preheated with a blowtorch. It was a mystery why, for they had successively put in four spares and still Number 3 performed in the same erratic manner. But today she took off like a startled dove at the first touch of the coxswain’s button. Pure luck that was, for there was not a chance to use the torch with watchful umpires writing down all they saw.

The Castor Beans pawed through the returned boats, looking for error, but their search was unsuccessful. Boat boxes were correct, down to the first aid kit, as was the power installation and the handling. Fraser drew another four-o and was excused.

From ADMIRAL'S INSPECTION by Malcolm Jameson (1940)
Hab Module100 tons
Consumables25 tons
Other Payload75 tons
Total Payload200 tons
Propulsion Bus
Engine+Radiator200 tons
Tankages+Keel100 tons
Dry Mass475 tons
Loaded Mass500 tons
Propellant Mass500 tons
Wet Mass1000 tons

The discussion thread about 'Industrial Scale of Space' veered, among other things, into a discussion of patrol missions in space. My first reaction was that (so long as you aren't dealing with an interstellar setting) there is no place in space for wartime patrol missions. But the matter might be more complicated, and for story purposes probably should be.

According to The Free Dictionary, patrol is The act of moving about an area especially by an authorized and trained person or group, for purposes of observation, inspection, or security. This fits my own sense of the word, and is in fact a bit broader, 'security' including SSBN patrols, which are not observing or inspecting anything, just waiting for a launch order if it comes.

In a reductionist way you could say that all military spacecraft are on patrol, since they are all on orbit, and if they are orbiting a planet they have a very regular 'patrol area.' But this is not what most of us have in mind. We picture a patrol making a sweep through an area, looking for anything unusual, ready to engage any enemy they encounter, or report it and shadow it if they cannot engage it.

Back in the rocketpunk era it was plausible that, say, Earth might send a patrol past Ceres to see if the Martians had established a secret base there. But (alas!) telescopes 'patrolling' from Earth orbit can easily observe the large scale logistics traffic involved in establishing a base; watch it depart Mars and track it to Ceres. If you want a closer look you can send a robotic spy probe. If you engage in 'reconnaissance in force' by attacking Ceres, that is a task force, not a patrol.

In an all out interplanetary war there may be plenty of uncertainty on both sides, but very little of it can be resolved by sending out patrols.

But of course all-out war is not the context in which the Space Patrol became familiar. I associate it with Heinlein's Patrol; apparently the 1950s TV series had an independent origin (unlike Tom Corbett, who was Heinlein's unacknowledged literary child).

The rocketpunk-era Patrol, which in turn gave us Starfleet, was placed in the distinctly midcentury future setting of a Federation. This is as zeerust as monorails. But plausible patrolling is not confined to Federation settings. It can justified in practically any situation but all out war.

Orbital patrol in Earth orbital space will surely be the first space patrol, and could be imagined in this century. It might initially be a general emergency response force, because travel times in Earth orbital space are short enough for classical rescue missions. On the interplanetary scale, with travel times of weeks or more likely months, rescue is rarely possible. But eventually power players will want some kind of police presence or flag showing in deep space.

As so often in these discussions, I picture a complex and ambiguous environment in which policing, diplomacy, and sometimes low level conflict blur together. To take again our Earth-Mars-Ceres example, there are kinds of reconnaissance that cannot be carried out by robots (short of high level AIs). If Ceres closes its airlocks to liberty parties from a visiting Earth patrol ship, that conveys some important intelligence information.

The ships that perform these missions will be fairly large (and expensive). They must carry a hab pod providing prolonged life support for a significant crew: at least a commander and staff, SWAT team of espatiers, and some support for both.

Let us say a crew of 25—which is cutting the human presence very fine. Now we can venture a mass estimate. Allow 100 tons for the hab compartment plus 25 tons for crew and stores plus 75 tons other payload, for a total payload of 200 tons. Let the drive bus be 200 tons for the drive, including radiators, and 100 tons for tankage, keel, and sundry equipment.

Our patrol ship with a crew of 25 thus has a dry mass of 475 tons, mass fully equipped 500 tons, plus 500 tons propellant for a full load departure mass of 1000 tons. Cost by my usual general rule is equivalent to $500 million, perhaps $1 billion after milspecking, expensive compared to military planes, cheaper than major naval combatants.

This is no small ship. If the propellant is liquid hydrogen the tanks have a volume of about 7000 cubic meters, equivalent to a 7000 ton submarine. The payload section is about two thirds the mass of the ISS and of roughly comparable size, though the hab is probably spun giving the prolonged missions.

Armament is necessarily modest. The 75 tons of additional payload allowance probably must include a ferry craft for the espatiers and an escort gunship or two, plus their service pod, leaving perhaps 15-20 tons each for kinetics and a laser installation. The laser might be good for 20 megawatts beam power, with plug power from the 200 megawatt drive engine.

This ship is no laser star, but the laser is respectable. Assuming a modest 5 meter main mirror and a near IR wavelength of 1000 nanometers, at a range of 1000 km it can burn through Super Nano Carbon Stuff at rather more than 1 centimeter of per second. Its armament is also rather 'balanced.' My model shows that this laser can just defeat a wave of about 1000 target seekers, each with a mass of 20 kg, closing at 10 km/s—thus a total mass of 20 tons, comparable to its kinetics payload allowance.

Deploying troops, or personnel in general, is impressively expensive: About three fourths of the payload and cost of a billion dollar ship goes to support and equip a crew of 25, with perhaps a dozen espatiers. For comparison the USS Makin Island (LHD-8) displaces 41,000 tons full load, carries a crew of 1200 plus 1700 Marines, and costs about $1.8. So by my model it costs about as much to deploy one espatier as 80 marines.

And this ship is about the minimum patrol package, so standing interplanetary patrol is a costly and somewhat granular business, something not everyone can afford.


TONY: I was maybe a little bit hasty earlier in saying that patrolling was of no value. It does have the value of giving you immediate reaction capability in a crisis. And in an environment where transit times are weeks or months, that can be important. IOW, while there may well be no physical horizon to patrol beyond, there is a time horizon.

However…a patrol vessel for that purpose could not be a relatively fragile assemblage of modules and cargo. This ship is going to have to fight it out with whoever else has a patrol vessel on-station — as well as any local forces that might exist — then dominate the local space until reinforcements arrive. So it's either got to be analogous to a pre-WWI overseas station cruiser, or the operator has to accept abandoning the hab and interplanetary drive (perhaps permanently) in order for the rest to be able to fire and maneuver effectively.

FERRELL: I don't think that "space patrols" would be like navy, or even air force patrols. It would be more like a giant figure-8 in the sky. Only with weapons and spy-gear...I do think that the 'patrol ship' would have extensive spin-hab and payload sections, but I think that the weapons mounted on the ship would be mostly point-defence, while the ship would also carry drones that mount the offensive weapopns (missiles and/or lasers)and be controlled from the ship. I also think that 'partols' would be more like convoy escorts (or raiders), 'show-the-flag' type, area security (like orbit), but I don't think you're going to send a billion dollar spacecraft from orbit 'A' to orbit 'B' and back again, just on the off chance that they would run into an enemy 'craft. It would be more like the bomber-interceptor type of combat. Deverting a 'show-the-flag' patrol to a hot-spot would be the exception rather than the norm. The only reasons I can see that you'd have these ships on a 'patrol' like Rick has discribed, is to keep close to convoys, unfriendly folk, or as mobile intelligence-gathering platforms. The customs/law-enforcement/anti-piracy/counter-terrorisim mission for your espatiers would be secondary. I further think that 'patrol ships' could be more like a mobile space station that are sent to orbit a planet or moon for short amount of time, and then off to the next target.

So...'space patrols' aren't going to be like 18th century sailing navy patrols, or even modern-day SSBN patrols. If you could send railroads on combat patrols, 'space patrols' would be like that...

ELUKKA: Shameless plug: I happened to design a paramilitary patrol/interceptor ship recently. Well, not really a coincidence as it was inspired by a previous discussion here. It'll manage an interplanetary flight but I imagine it's made more for smaller operational areas, say a gas giant's moon system.

Open-cycle gas core NTR engines, thrust around 1 g (or nearly 3 with LOX injection at the cost of some isp), delta-v 30 km/s. Propellant is methane. There's a secondary chemical engine for operation near other craft as the main engines do have radioactive exhaust.

It has a fairly big 140 tonne hab module and a turreted laser. Total mass is about 2,200 tonnes. Besides going with a high-thrust engine, I find it surprisingly similar to the craft Rick described!
The hab's got a wraparound radiator and the engines get rid of the brunt of their waste heat by the way they work (open-cycle cooling) but… no, they're probably still not enough. I did a terrible thing and sorta threw on radiators that I thought looked good instead of running the numbers. :P
(I did mathify the rest of the design though)

click for larger image

click for larger image

EngineOpen-cycle GCNR
Docking EngineChemical
ΔV (High-Gear)30,000 m/s
Wet Thrust (High-Gear)1g
ΔV (High-Gear)30,000 m/s
Wet Thrust (Low-Gear)6g
ΔV (Low-Gear)? m/s
Habitat Module140,000 kg
Weaponsx2 laser turret
Wet Mass2,200,000 kg

FERRELL: Elukka:, your ship is great! As an interceptor or convoy escort, it looks like a good compromise between cost and mission demands. I could see it being used very handlly as a customs inforcer or as an asteroid deflector, as well as other missions. As a secondary armed spacecraft, this is what I imagined a "real" space fighter would be like. Your ship would be perfect for an independent colony or minor power.


     We already have space patrols, and we call them spy-sats.
     I just don't see this scenario. The cost, the mass, the vulnerability of a single mirror as our primary means of offense and defense.
     So your laser can burn 1000 incoming big projectiles? Big deal. This has always struck me as the major flaw in single laser configurations—the assumption that the enemy won't just buckshot you to death.
     Imagine this patrol ship up against robot ships using auto-canon to blast out clouds of shrapnel heading your way from beyond your laser's range and riding into your projected path of travel.
     Sure, they miss a lot, but they have hundreds of thousands of projectiles zipping towards you too. How do you track a cloud? How do you blast it? Can you paint that much space with your laser before overheating? (the answer is that is debatable, the classic Purple/Green debate)
     All it takes is for the shrapnel to rip apart your mirror, or radiators, or sensors, or whatever.
     And then boom...
     Here comes the slow nuke to turn your patrol ship into a flash of light that no longer exists.
     More realistic are lots of robot patrols—cheap and expendable. They swarm. They spy. They report. And eventually they fail and self-destruct. No muss. No fuss.
     Plus they're cheap and easy. NASA could build these today if it wanted.
     Sorry. I just don't see this scenario as very plausible.

     Hey—I just had a weird idea for these drone ships.
     Do you think it would be possible to design them to cannibalize themselves for ammunition?
     In other words, they'd lock onto a target, fire their basic store of ammunition, and if the target wasn't destroyed, the drones would be built in such a way that they could begin consuming their parts for ammo until the drone was nothing but the basic power unit, firing computer, attitude determination and control system (ADCS), and the rail gun.
     Everything else. The shell. Primary thrusters. Etc… Fired down range. I wonder how much you could scavenge if you had no intention of bringing it home again. (This is done in the simulation game High Frontier, except more so. The ships have Santa Claus machines that can canabalize unused equipment and manufacture needed equipment)

(Somebody suggested to Clay that patrol ships would be for inspection, not main-line combat work. Therefore it wouldn't matter that patrol ships were vulnerable to a sky full of buckshot)

     Well, these patrol ships are obviously meant for combat to some extent if we are arming them. My argument is that arming them, and indeed sending them, is pointless.
     Patrol ships can't outfight the drones cost effectively, nor can they out-patrol the drones either from a cost-effective standpoint.
     And I've read the arguments regarding space battle here and elsewhere, but I think they bear repeating in this context.
     There just isn't a scenario where dispatching isolated patrol ships with limited weaponry for long-range reconnaissance makes any sense unless you are actively trying to get attacked in order to justify going to war (a la American PT boats harassing Japanese warships pre Pearl Harbor)

     My overall view on this is that any sort of presence patrol will be in the form of a station, not individual ships. It's far cheaper in remass, and you get more ship for your money, as you don't need deep-space endurance. There might be a few ships for flag-showing patrols, but those would be very rare.

     Tony, Yes, but there are two major problems with that. First, the fact that you spend as much time coming back as you did going out. Second, the fact that you are only "on station" for 1% of the time. Yes, you can stop at the target, but the mass penalties for that sort of thing are rather severe.

     Elukka: The ship looks impressive. Do you have any more numbers?

     Clay, a single big laser will tend to be more powerful than several small ones. It has a longer effective range, and thus starts burning things sooner. I do agree that a few defense lasers would be helpful, but the main offensive laser will likely be a single unit.
As for attacking lasers, I'm in favor of sand clouds.
The point of armament is to provide the ship with some sort of chance against an enemy. If they can't outfight drones (which I won't take as a given) they still will do better with guns than without guns.

     If anyone's interested in ship design, I've recently made a spreadsheet that automates a lot of it. It was originally for Rocketverse but it's pretty adaptable. If you want a copy, I'll find a way to get it to you. I also have a Newtonian space battle tracker that works with it.

     I think patrolling in space is a waste of time. You're wasting energy and reaction mass putting your ship in one particular orbit — thereby pretty much guaranteeing no enemy will be encountered in that orbit.
     The life-support cost is tremendous — not just in launched mass but also radiation exposure and the "opportunity cost" of having those crewmen on a trajectory to point A rather than any other point. Given the capabilities of modern drones I can't imagine any spacefaring power which would send out humans to snoop around potential threats.
     Instead of a patrol ship, I'd envision something like a frontier fort — a base from which missions can be launched, with telescopes to monitor that whole part of the Solar System, hardened defenses, long-term self-sufficiency, etc.
     One can imagine "forts" like that in key locations around the system — Saturn orbit, possibly the Jovian trojans, etc.

     The only reason to send manned ships is for "courtesy visits" and that's a pretty flimsy excuse. If your intel people are reasonably competent, they'll have agents aboard cargo ships going there. I somewhat agree with the "fort" theory, but I'd go farther and make it a full base, with facilities for crew and family, moderate repairs, etc.

     Patrolling will reduce the time horizon for the force which engages in it, which is really the point, I think.

Arguments that the patrol vessel is vulnerable are somewhat moot, since if the vessel is attacked, then it is an unambiguous signal that hostilities have commenced (unless the owning Power is willing to tolerate the loss for political or military reasons of their own).

     I would argue that a patrol vessel on the lines Rick has described would be a two part vessel. The Hab would be an independent space vehicle in its own right, while the major portion of the ship (keel, engines, radiator main assembly, Liniac and mirror) are also an independent vessel. Once the decision is made to land a shore party (or liberty party for that matter), the hab undocks and trundles off while the weapons platform remains in the High Guard position (Overwatch position higher in the gravity well).
     For Elukka, who seems to have a flare for this sort of thing, the main platform would look somewhat like a paper airplane, with large triangular radiators along the truss. The engine is at the wide end (radiators corresponding to where most of the heat generation is) (engine might be at the pointy end if it emits radiation) and the mirror is in the nose, perhaps in a "thimble" turret at this scale. Tankage, KKV's etc. are in the spaces between the "wings", and the hab is hanging off one of the hard points. Depending on the scale (and given the description), the hab might resemble a pair of spare tires hanging from a medium length girder bridge (counter rotating so they do not impart momentum to the carrier vessel). If you really want to take the "paper airplane" analogy seriously, then there are three fins and most of the other hardware is attached to the truss on the "top" of the paper airplane.

     The big advantage of this design is the carrier need not go with a manned hab, and indeed the hab could be the control station for a constellation of these vehicles, making it adaptable for everything from patrolling to being the nucleus of a constellation or task force.

It wouldn't reduce the time horizon by enough to matter in most cases. Not if the opponent was smart. If you're basically going there, swinging through the system, and leaving, the time in the system is going to be minimal compared to transit time. It's like sending "patrols" to, say, Deigo Garcia from the US by steaming a ship all the way around the world, and not stopping there, just sailing close by once, and leaving. Oh, and the ship can't turn around once it's past. Response time might be less if you have two, but no matter what, they'll wait until you've passed to make trouble.
If you choose to stop in orbit, that's slightly different, but unless you only want occasional visits, it makes a lot more sense to build a permanent base. You only have to ship supplies, and your crews will be a lot happier. Plus, the ships you have won't have to carry stuff like spin habs, as the missions aren't that long.

     I think some people are not understanding what a patrol is in the context of near and medium term interplanetary spaceflight. The bojective will not be to go there and come back, or go to several places and pass through each without stopping. The objective will be to go and stay for the suration of the mission (months or years), so that if anything happens somebody will be on-hand to handle it. The patrol area is not a large volume of space. It's the tactically relevant volume of space around a point of interest, like a planet or an asteroid. So yes, there are some affinities with the fortress analogy and the spy sat analogy, but only some.
The patrol ship needs to do three things:

  1. Go to the patrol area
  2. Remain on station
  3. Fight if and when the time comes to fight

     Notice that these three requirements would best be met by three different spacecraft. But since we don't have three different spacecraft, we'll make do with three different modules:

  1. Interplanetary propulsion
  2. Habitation
  3. Combat
     The interplanetary module takes the hab and the combat modules to the patrol area. The hab is lived in and the combat module manned while on patrol station. If shooting starts, the combat module detaches from the hab and goes to work.

     Note that the combat module need not be monolithic. It could be augemtned by orbital or even self propelled sensor and weapon platforms. The reason for its existence — and the existence of the whole patrol ship complex — is to place humans in the loop in tactical time. It doesn't exist to be a tripwire, or to be here one day but gone the next. It exists to be available to fight and to actually fight when called on to do so.

     I'll note that I am only against deep space patrols. Ships in orbit around an enemy planet (or a partially enemy planet, such as a multi-faction world or a friendly world that's under invasion, or a potentially enemy planet, that you suspect but aren't sure is planning something nefarious) can reasonably make use of some patrol tropes, although it's not quite the same.
     One issue with "patrolling" this close to an enemy planet, without access to stealth, is that the enemy is unlikely to let you unless you show up in enough force to strongarm their defenses. If relations are merely strained rather than actively hostile, though, then a show-the-flag mission is viable.

Tony: "I was maybe a little bit hasty earlier in saying that patrolling was of no value. It does have the value of giving you immediate reaction capability in a crisis."

     Only if you know in advance where the crisis is going to turn up.
     The extreme difficulty of changing course in space means that you cannot hang around in a trouble spot and be ready to give chase if something comes up. The mere size of space means that there isn't going to be any narrow region of space you can keep an eye on to keep most trouble under wraps, unless that region is in orbit around a planet.

Clay: "This has always struck me as the major flaw in single laser configurations—the assumption that the enemy won't just buckshot you to death."

     I think there is practically no point defense that can help against buckshot. Even a small amount of armor, however, can.

Byron: "My overall view on this is that any sort of presence patrol will be in the form of a station, not individual ships."

     A fleet of ships can be in several places at once, which is useful when you're trying to keep an eye on an entire planet. I don't think a patrol craft benefits that much from being large, except in as far as that it gives you more room for crew amenities to endure the long boredom.

     Milo, you misunderstand what I meant. I was trying to say that a long-term patrol won't be carried out by ships on rotation from a home base at a different planet. Instead, a base will be constructed in the system, and ships will be more-or-less permanently assigned there while the crews rotate.
     The problem is that to be capable of carrying a crew on an interplanetary voyage, a patrol craft will have to be large. My stations solve that, as they only have to deal with the normal crew under peacetime conditions for a month or two at most. If you need to move it back home for a refit or something send a skeleton crew.

     Milo, the whole point of patroling is that you don't know when or where the crisis is going to be, so you maintain a presence where you have an interest, ready to react when one does.
     Also, the size of space and the difficulty in changing direction dictates precisely that you can only focus on well-defined regions of interest. The only such well-defined regions are those within tactically relevant distance of a point of interest, like a planet or an asteroid. Anyplace else has little if any strategic value and just ain't worth fighting over -- not that anybody would go there in the first place.
     About the only situation in which you might get combat away from natural bodies is if two powers launch comparable warships through the same window at the same destination, and either one or both ofthem had enough spare delta-v to maneuver into combat, fight it out, and still make any necessary orbital correctios and orbital insertions at the destination.

     Milo, Ahhh, but that small amount of armor isn't so small given mass constraints. Even a little—and we don't know ahead of time how "little" it gets to be because we don't know what the scenario will be—can radically reduce the overall amount of Delta-v available, or else run up the price tag.
     And there's a Catch-22 with up-armoring your ship. Once you do a little, and the price goes up, then you feel the need to protect it even more since now that ship represents a bigger investment. And so on and so forth.
     And yes, I know a big laser is theoretically better than several small ones, but it also puts all your eggs in one basket. Again, you don't need to destroy big-gun patrol ships with buckshot, you just need to screw up their mirror or mess up their radiators, etc…
     That's the problem with space warships. They're like flying aircraft carriers in modern war. Theoretically useful, but too vulnerable to justify the expense.
     In this case, we either have real warships or automated spysats. Why build a ship that isn't powerful enough to really fight, only to take a look at stuff that can be observed at far less cost by automated spysats.
     Even if there is trouble, the patrol vessel isn't really a warship. It will quickly get overwhelmed, and it won't take much to do it.

MR. BLUE: Don't forget one very important role for Patrol Ships: Deep Space Search and Rescue. Think of it as an analog to today's Coast Guard cutters.
     So, the espatiers would be have a good levening of Pararescue types to effect rescues inside damaged ships. Add a pretty good trama center onboard ship.
     The ship would need to be armed, but it would not really be used for classic warship to warship combat. You would mostly use the laser to vaporize or move any potentially hazardous debris. That laser would also come in handy if you needed to slag a fleeing smuggler or rogue missle.


I will split my responses to points into mainly technical and mainly strategic.


I've come to be doubtful that armor is worth the mass penalty. Any kinetic strike that saturates a decent laser defense will probably overkill the target, while a laser will zero in on vulnerable points rather than just zap away at armor.

For the same reason, military craft might not look much different overall from civil ships, apart from the actual weapon mounts.

The advantage of range (and more zapping intensity at any given range) justifies a single main mirror, I think. Tanks have one main gun, and they are much more subject to being engaged from an unexpected bearing.

I like the idea of being able to detach sections. There are some mass penalties, but mostly pretty minor ones. One constraint, in my presumed tech, is that the laser draws electric power from the main drive, so is necessarily connected to it.

For interplanetary missions the distinction between 'ship' and 'station' is quite blurred. Attach a drive bus to a station and it becomes a ship; remove the drive bus from a ship and its hab becomes a station.


The ship I outlined is not intended for 'combat patrols.' In an all-out shooting war the patrol ships may as well be mothballed for the most part.

They are intended for missions more comparable to those of coast guard cutters, Victorian gunboats, and Teddy Roosevelt era 'peace cruisers.' Basically wherever a polite request and a 20 MW laser will get more compliance than the polite request by itself would.

So the armament is not primarily to engage peers but to provide a clear dominance over jury-rigged or other light armament.

Whether there is a valid mission for these ships is a valid question. To be strictly realistic, there probably won't be anything beyond Earth orbital space but research stations, and an extremely minimal military/police presence comparable to Antarctica today.

But if you are going to assume a future Solar System filled with all sorts of activities, power players are going to want intermediate coercive options between sternly worded protests and interplanetary kinetic/nuclear strikes.

From SPACE PATROLS by Rick Robinson (2010)

The comment thread on my previous post about space patrols raised the issue of base stations for more prolonged missions, extending to years.

This has application far beyond military or quasi-military patrols. In fact it is fairly fundamental to any extensive, long term human presence in deep space. Whether or not we put permanent bases on the surface of Mars, Europa, or wherever, we will surely place permanent or semi-permanent stations in orbit around them. Particularly because the stations can be built in Earth space, where the industry is (at least initially), and flown out to where they will serve.

Hab structures intended for prolonged habitation should be fairly large, if only because if you are going to live for years in a can it should be at least be a roomy one. And they must be thoroughly shielded against radiation, much more than ships that you only spend a few months aboard every few years.

So let us play with some numbers. Make our spin hab a drum, 200 meters in diameter and 100 meters thick. Volume is thus about 3.14 million cubic meters. The ISS has about 1200 m3 of pressurized volume and a mass of some 300 tons, for an average density near 0.25, but the mass includes exterior structures such as keel and wings. Let average interior density be about 0.16, for a mass of 500,000 tons.

If we allow 100 cubic meters per person the onboard population (whether 'crew' or simply residents, or a mix) can be up to 30,000 people. This is about twice the density of a middle class American urban apartment complex. Given that much of the usable volume must be working areas, public spaces, and so forth, the actual crew or population might be more on the order of 10,000 people, equivalent to a decent sized small town or a fairly large university or military base. Thus the hab has 10 times the volume of an aircraft carrier and twice as many people.

Spin the hab at 3 rpm and you get almost exactly 1 g at the rim.

By my general rule the cost of this hab is on order of $500 billion. That is a steep price tag, but on the other hand it is only five times the cost of the ISS, and you need very few of these unless you are engaged in outright colonization.

Now, shielding. The standard for indefinite habitation is about 5 tons per square meter of cross section. (Earth's atmosphere provides about 10 tons/m2.) Portions of the hab where people do not spend much time, and exterior to where they do spend time, can be counted toward the shielding allowance. So let us say that the outer 10 meters of the interior (about 35 percent of the volume) are used for storage, equipment rooms, and the like. This provides about 2 tons per square meter of shielding, 40 percent of the requirement.

The remaining 3 tons per square meter of exterior shielding must cover about 125,000 square meters of surface, so shielding mass is about 375,000 tons, adding 75 percent to the mass of the hab, now 875,000 tons. This shielding need not be 'armor.' As I recall, water provides pretty good shielding against GCRs, your biggest radiation problem, and water is so useful that having 375,000 tons of it on hand in a reservoir will never be amiss.

Moreover, to move the hab you can vent off the water (or pump it out) and not need to lug the mass, assuming you can replace it wherever you are going. The deep interior of the hab, more than 25 meters from the surface (about 28 percent of the volume) is still shielded by the rest of the hab structure, so the hab can carry a reduced population during the transfer.

You are still moving a half million ton payload, so don't expect to rush it unless you have a really badass drive bus handy. Habs being repositioned across the Solar System probably travel on Hohmann orbits, and have drive accelerations of a few dozen microgees, good for about 1 km/s per month of steady acceleration.

For a smaller hab structure, scale down the linear dimensions by half, to 100 meters diameter and 50 meters thick. Structural mass, volume, and capacity are all reduced by a factor of 8, to 400,000 cubic meters, 60,000 tons, and a crew / resident population of about 1500-4000. Our 'mini' hab is now broadly comparable in volume, mass, and crew to an aircraft carrier.

Surface area is only reduced, however, by a factor of four, to about 30,000 square meters. Moreover, the smaller hab provides less interior self-shielding. If we keep the same proportions our internal reserved zone is just 5 meters deep and provides only 20 percent of the needed protection, not 40 percent.

We now need about 120,000 tons of shielding — twice the unshielded mass of the hab. If we move the hab fully shielded our payload mass is 180,000 tons. Remove the shielding and payload mass is just 60,000 tons, but no part of the smaller interior is fully self-shielded, so any crew on board during a 'light' transfer must be relieved every few months. On the bright side, if you have a 100 gigawatt drive bus floating around, or about $100 billion to buy one, you can take a fast orbit and get there in a few months.

The image shows a drum-hab station ship with a spin hab of the full sized type described above, 200 meters in diameter by 100 meters thick, fitted with a heaviest class drive bus for transfer. I am delicately ignoring details of the connection between the spin drum and the hub structures.

The shuttles approximate the NASA Shuttle, as a visual size reference. The deep space ships docking up to it are large fast transports, 300 meters long, ten times heavier than the patrol ship discussed last post. The station ship itself is about 675 meters long by 450 meters across the outrigger docking bays.

In my image the station ship is no aesthetic triumph. Allowing for my limitations as an graphic artist (compare to commenter Elukka, from the last comment thread), the transport class ships don't look too bad, but the station ship merely looks tubby instead of grand. Some modest architectural improvements might yield a more impressive appearance with little change in overall configuration.

Of course the interior will matter immeasurably more to the people on board. Mostly, presumably, it will resemble the interior of a very large oceangoing ship, corridors and compartments, probably including some fairly imposing public spaces, comparable to the grand saloon of a 20th century ocean liner or even larger. It can be as elegant or as sterile as you like (or both, depending on deck and sector). The third popular choice, rundown industrial gothic, is constrained by how far you can go in that direction before the algae dies or the air starts leaking out.

From HOME AWAY FROM HOME by Rick Robinson (2010)
Ray McVay
Rocketpunk Patrol Ship
Dry Mass76.2 metric tons
Wet Mass384.6 metric tons
Mass Ratio5
Length Z73 meters
Length Y20.1 meters
Length X15.2 meters
Enginex2 F-26-A LH/LOX
Thrust7.7×106 N
Acceleration0.5 g
ΔV8,200 m/s

This is the same one from the other day, only dressed up with a nice logo and some stats. These are realistic capabilities made courtesy of the charts and other information available from Atomic Rocket and inspiration from Rick Robinson's Rocketpunk Manifesto.

My PL differs from the one in Rick Robinson's article in a few key areas. The main difference is that it is not made for long hauls. It only has a delta v of about 8200 m/s. This will not get one far in the solar system but it allows a forward deployed Patrol Craft a sufficient "range" to perform many of the missions we discussed in the last post on Building a Space Navy. Our little A-Class has enough Delta V to shape a light-second orbit around a convoy in deep space, conduct SAR missions anywhere in cis-lunar space, or to reach any moon of Saturn from any other moon. Obviously, this rocket is mostly propellant (mass ratio 5). If you drew lines through the side view of the rocket that bracket the docking rings, you would encompass the entire pressurized volume. I've got to say, it's nice to work on a warship for a change — I don't have to make it economical to run!

One of the interesting things about this design is actually the freedom the little carried craft gives me. It was a throw-away touch, originally — a design borrowed from another project. But as I got to looking at the little thing, I realized that it's about the size of the Saturn V stage/Apollo/LM stack. That means it should be able to go from Earth Departure to Lunar orbit. That means that it has the Delta V to ferry crew to and from a Patrol Craft on station away from the convoy. That means, like submarines, our Patrol Craft can have two crews and stay out for a lot longer than otherwise. This is one of those realistic touches that I hope add to the charm of the rocket's design.

ed note: a 1500 nanometer near infrared laser with a 10 meter fixed mirror can have a 4 centimeter spot size out to 220 kilometers or so. A 4 meter mirror can have a 4 centimeter spot size out to 87 kilometers or so.

Nuke Guard

If you have an atomic-rocket future you will need atomic rocket fuel. This means atomic fuel plants to turn raw uranium ore into refined fission fuel reactor elements (or whatever), and fuel reprocessing facilities to reprocess spent fuel rods into fresh ones.

Unavoidably this will produce sizable amounts of weapons-grade fissionables, just the thing for making your very own nuclear weapons.

The Nuke Guard is the military security force charged with preventing any of this stuff from being stolen. Because the last thing you want is a load of Plutonium-239 going walkies out the door and into the hands of terrorists or revolutionaries. Nuclear Security in other words.

Much like the Spaceguard this might have to be a mult-national force. So they can keep each other honest. This also might have to be a full military service instead of a civilian one. Let's face it, security guards at a plant are seldom equipped to fend of a full military raid by a hostile foreign power trying to capture stocks of weapons-grade plutonium.

And if you think the Nuke Guard is hard-core with absolutely no sense of humor, obviously you have not yet met the Antimatter Guard.


Mass drivers and other rockets can be used to alter the orbits of asteroids (and mass drivers can use rocks from the asteroid itself as a built-in source of propellant). Popular with asteroid miners who want to nudge their claims into different orbits. Unpopular with the astromilitary of all nations, who think that civilization-destroying asteroid bombardment is not a power one wants to give to rock-rats.

The "Dinosaur-killer" asteroid was probably about 10 kilometers in diameter, and it caused a freaking mass extinction of three-quarters of plant and animal species on Terra. There are approximately ten thousand asteroids in the belt of size 10 km or larger. And of course there are much more than ten thousand "fun-sized" asteroids, not large enough to wipe out civilization on Terra, but big enough to obliterate a nation that you dislike. Space faring nations with asteroid moving technology will look at the list of small asteroids, look at the list of nations hostile to them, and start to get ideas.

If asteroid moving technology is cheap enough it won't be a game just for nations, you might find mere corporations and James Bond villains getting into the act.

It would let me protect the Earth from asteroids. In fact, for a small fee I would protect the Earth on a monthly basis, locating rocks that could be steered into the Earth and then not doing it if the cheque didn't bounce.

From a comment by James Nicoll (2005)

Spaceguard: stop malicious asteroids

Once asteroid-moving technology is available, one can foresee a branch of "spaceguards" in each astromilitary, patrolling the solar system to prevent unauthorized changes in asteroid orbits. Any rock-rat, corporation, or nation that wishes to move an asteroid will have to file a proposed trajectory and request a permit from the Spaceguard.

(ed note: Originally I called this branch the "Orbit Guard." I have gone to the trouble to change the name for two reasons:

[1] The term Spaceguard is already being used for this function.

[2] The term "orbit guard" is a much better fit for the space-going version of the Coast Guard.

I regret any inconvenience this has caused.)

The Guard would keep a close watch on all asteroids. If one starts to move without a permit, or if one with a permit strays off the filed flight plan, military spacecraft of the various space faring nations will pounce and blow the snot out of it. Spaceguard ships will be armed, since the evil asteroid movers will probably shoot back. Of course prior to that the evil asteroid movers will have all their crew and equipment scrubbed of anything identifying the nation behind this heinous act, since it easily fits into the category "act of war", or even "genocide."

Probably there will be a branch of spaceguards in all of the space faring nations. They will not just watch asteroids, they will also keep a close eye on the spaceguards belonging to other nations, just to keep them honest. If nation X has a spaceguard, enemy nation Y will want their own spaceguard as well. Otherwise nation X might be tempted to turn a blind eye to somebody targeting nation Y's capital city with an errant asteroid.

Requests for asteroid moving permits will have to be filed with the Spaceguards of all nations. Things might get a bit political here, since giving all the Spaceguards veto power can be abused. Say, if nation X was currently angry with nation Y, nation X might pressure their Spaceguard to automatically veto any asteroid moving requests from nation Y using specious reasons. Some kind of appeals process will have to be available.

Spaceguard: stop random asteroids

And who knows? Spaceguard might actually find an errant asteroid that just happened to be naturally on collision course with Terra, instead of uncovering a Sinister Plot by Dr. Evil. It will be real nice to have the spaceguards there to bump it off course. Just ask the dinosaurs. Oh, that's right, you can't because an asteroid made them all go extinct.

Those who think such impacts do not happen in the solar system anymore have forgotten about the multiple 6,000,000 megaton impacts that Comet Shoemaker–Levy 9 inflicted on Jupiter in 1994.

Arthur C. Clarke invented an asteroid early warning system called "Project Spaceguard" for his novel Rendezvous with Rama in 1972. Clarke was most gratified when a real live Spaceguard was created in 1992 (duely giving Clarke credit for the name). David Levy stated in an interview "The giggle factor disappeared after Shoemaker-Levy 9." After the impact of Comet Shoemaker-Levy 9, asteroid detection programs all over the world abruptly received greater funding.

The main point is it is quite easy to nudge an asteroid off collision course if you have a few decades of lead time. If you only have a few days notice you are going to have to use nukes. So start discovering and surveying all those Near-Earth objects right now.

Spaceguard: range safety officers

A separate but closely related duty performed by the Spaceguard is that of range safety officer. If civilian ships can be used as weapons of mass destruction, in an emergency the Spaceguard can remotely trigger the civy ship's self destruct device. Spaceguard shares this responsibility with the Launch Guard. Generally the Launch Guard's range safety keep watch around spaceport launch sites while Spaceguard's range safety officers keeps watch everywhere else. As far as Spaceguard is concerned, a civilian spacecraft on collision course with a colony is the functional equivalent of a rogue asteroid. Only of artificial origin and hopefully already equipped with a handy self destruct.

Spaceguard will also blow up any civilian-owned torchship which starts to aim its lethal exhaust at something vulnerable. Again, regardless of whether it was deliberate or unintentional. The ship might be given a radio warning first, but they have not complied within the specified time limit, it is kaboom time. Spaceguard does not know or care if it is due to a drunk pilot or terrorist activity: civilians are forbidden from giving impromptu demonstrations of the Kzinti lesson.

Spaceguard: science fiction author's friend

Spaceguard is a nice concept for SF authors, since it gives a plausible reason for the very existence of astromilitary. And of course civilian boom-towns and settlements will spring up around any military bases. There is money to be made supplying all those enlisted people with gambling, whiskey, and prostitutes. Especially if the base is orbiting Saturn or somewhere equally remote. This gives SF authors an economic reason for an extensive manned presence in space.


Sooner or later, it was bound to happen. On 30 June 1908, Moscow escaped destruction by three hours and four thousand kilometres—a margin invisibly small by the standards of the universe. Again, on 12 February 1947, yet another Russian city had a still narrower escape, when the second great meteorite of the twentieth century detonated less than four hundred kilometres from Vladivostok, with an explosion rivalling that of the newly invented uranium bomb.

In those days, there was nothing that men could do to protect themselves against the last random shots in the cosmic bombardment that had once scarred the face of the Moon. The meteorites of 1908 and 1947 had struck uninhabited wilderness; but by the end of the twenty-first century, there was no region left on Earth that could be safely used for celestial target practice. The human race had spread from pole to pole. And so, inevitably…

At 09:46 GMT on the morning of 11 September, in the exceptionally beautiful summer of the year 2077, most of the inhabitants of Europe saw a dazzling fireball appear in the eastern sky. Within seconds it was brighter than the sun, and as it moved across the heavens—at first in utter silence—it left behind it a churning column of dust and smoke.

Somewhere above Austria it began to disintegrate, producing a series of concussions so violent that more than a million people had their hearing permanently damaged. They were the lucky ones.

Moving at fifty kilometres a second, a thousand tons of rock and metal impacted on the plains of northern Italy (about 1.25×1015 joules or 300 kilotons), destroying in a few flaming moments the labour of centuries. The cities of Padua and Verona were wiped from the face of the earth; and the last glories of Venice sank for ever beneath the sea as the waters of the Adriatic came—thundering landwards after the hammer-blow from space.

Six hundred thousand people died, and the total damage was more than a trillion dollars (which was a lot of money in 1973, about 5 trillion in 2017 dollars). But the loss to art, to history, to science—to the whole human race, for the rest of time—was beyond all computation. It was as if a great war had been fought and lost in a single morning; and few could draw much pleasure from the fact that, as the dust of destruction slowly settled, for months the whole world witnessed the most splendid dawns and sunsets since Krakatoa.

After the initial shock, mankind reacted with a determination and a unity that no earlier age could have shown. Such a disaster, it was realized, might not occur again for a thousand years—but it might occur tomorrow. And the next time, the consequences could be even worse.

Very well; there would be no next time.

A hundred years earlier a much poorer world, with far feebler resources, had squandered its wealth attempting to destroy weapons launched, suicidally, by mankind against itself. The effort had never been successful, but the skills acquired then had not been forgotten. Now they could be used for a far nobler purpose, and on an infinitely vaster stage. No meteorite large enough to cause catastrophe would ever again be allowed to breach the defences of Earth.

So began Project SPACEGUARD. Fifty years later—and in a way that none of its designers could ever have anticipated—it justified its existence.

From RENDEZVOUS WITH RAMA by Arthur C. Clarke (1973)

A potentially hazardous object (PHO) is a near-Earth object – either an asteroid or a comet – with an orbit that can make close approaches to the Earth and is large enough to cause significant regional damage in the event of impact. They are defined as having a minimum orbital intersection distance with Earth of less than 0.05 astronomical units (19.5 lunar distances) and an absolute magnitude of 22 or brighter. 98% of the known potentially hazardous objects are not an impact threat over the next 100 years. Only about 32 potentially hazardous objects are listed on the Sentry Risk Table as objects that are known not to be a threat over the next hundred years are excluded. Over hundreds if not thousands of years, "potentially hazardous" asteroids have the potential for their orbits to evolve to live up to their namesake.

Most of these objects are potentially hazardous asteroids (PHAs), and a few are comets. As of March 2021 there are 2,173 known PHAs (about 9% of the total near-Earth population), of which 158 are estimated to be larger than one kilometer in diameter (see list of largest PHAs below). Most of the discovered PHAs are Apollo asteroids (1,730) and fewer belong to the group of Aten asteroids (171).

A potentially hazardous object can be known not to be a threat to Earth for the next 100 years or more, if its orbit is reasonably well determined. Potentially hazardous asteroids with some threat of impacting Earth in the next 100 years are listed on the Sentry Risk Table. As of March 2021, only about 32 potentially hazardous asteroids are listed on the Sentry Risk Table. Most potentially hazardous asteroids are ruled out as hazardous to at least several hundreds of years when their competing best orbit models are sufficiently constrained, but recent discoveries whose orbital constraints are little-known have divergent or incomplete mechanical models until observation yields further data. After several astronomical surveys, the number of known PHAs has increased tenfold since the end of the 1990s . The Minor Planet Center's website List of the Potentially Hazardous Asteroids also publishes detailed information for these objects.

In May 2021, NASA astronomers reported that 5 to 10 years of preparation may be needed to avoid a potential impactor based on a simulated exercise conducted by the 2021 Planetary Defense Conference.


An object is considered a PHO if its minimum orbit intersection distance (MOID) with respect to Earth is less than 0.05 AU (7,500,000 km; 4,600,000 mi) – approximately 19.5 lunar distances – and its absolute magnitude is brighter than 22, approximately corresponding to a diameter above 140 meters (460 ft). This is big enough to cause regional devastation to human settlements unprecedented in human history in the case of a land impact, or a major tsunami in the case of an ocean impact. Such impact events occur on average around once per 10,000 years. NEOWISE data estimates that there are 4,700 ± 1,500 potentially hazardous asteroids with a diameter greater than 100 meters.

Levels of hazard

The two main scales used to categorize the impact hazards of asteroids are the Palermo Technical Impact Hazard Scale and the Torino Scale.

Potentially hazardous comets

Short-period comets currently with an Earth-MOID less than 0.05 AU include: 109P/Swift-Tuttle, 55P/Tempel–Tuttle, 15P/Finlay, 289P/Blanpain, 255P/Levy, 206P/Barnard–Boattini, 21P/Giacobini–Zinner, and 73P/Schwassmann–Wachmann.


In 2012 NASA estimated 20 to 30 percent of these objects have been found. During an asteroid's close approaches to planets or moons other than the Earth, it will be subject to gravitational perturbation, modifying its orbit, and potentially changing a previously non-threatening asteroid into a PHA or vice versa. This is a reflection of the dynamic character of the Solar System.

Several astronomical survey projects such as Lincoln Near-Earth Asteroid Research, Catalina Sky Survey and Pan-STARRS continue to search for more PHOs. Each one found is studied by various means, including optical, radar, and infrared to determine its characteristics, such as size, composition, rotation state, and to more accurately determine its orbit. Both professional and amateur astronomers participate in such observation and tracking.


Asteroids larger than approximately 35 meters across can pose a threat to a town or city. However the diameter of most small asteroids is not well determined, as it is usually only estimated based on their brightness and distance, rather than directly measured, e.g. from radar observations. For this reason NASA and the Jet Propulsion Laboratory use the more practical measure of absolute magnitude (H). Any asteroid with an absolute magnitude of 22.0 or brighter is assumed to be of the required size.

Only a coarse estimation of size can be found from the object's magnitude because an assumption must be made for its albedo which is also not usually known for certain. The NASA near-Earth object program uses an assumed albedo of 0.14 for this purpose. In May 2016, the asteroid size estimates arising from the Wide-field Infrared Survey Explorer and NEOWISE missions have been questioned. Although the early original criticism had not undergone peer review, a more recent peer-reviewed study was subsequently published.

From the Wikipedia entry for POTENTIALLY HAZARDOUS OBJECT

Sentry is a highly automated impact prediction system operated by the JPL Center for NEO Studies (CNEOS) since 2002. It continually monitors the most up-to-date asteroid catalog for possibilities of future impact with Earth over the next 100+ years. Whenever a potential impact is detected it will be analyzed and the results immediately published by the Center for Near-Earth Object Studies. However, several weeks of optical data are not enough to conclusively identify an impact years in the future. By contrast, eliminating an entry on the risk page is a negative prediction; a prediction of where it will not be.

Scientists warn against worrying about the possibility of impact with an object based on only a few weeks of optical data that show a possible Earth encounter years from now. Sometimes, it cannot even be said for certain what side of the Sun such an object will be at the time of the listed virtual impactor date. For example, even though 2005 ED224 has a 1-in-500,000 chance of impacting Earth on 11 March 2023, it is expected to be farther than the Sun at the time. Most objects on the Sentry Risk Table have an observation arc of less than 14 days and have not been observed for years.

There are 1146 near-Earth asteroids listed on the risk table with 36,637 virtual impactor dates. For each asteroid listed on the risk table there are on average about 30 virtual impactors. Only about 30 objects on the risk list are large enough to be considered potentially hazardous objects with a diameter greater than about 140 meters.

From the Wikipedia entry for SENTRY MONITORING SYSTEM

A related matter of space law that is also likely to spark conflict is asteroid redirection.  Some plans for asteroid mining involve bringing asteroids to Earth orbit to mine, instead of mining them in situ, and shipping the resulting products back.  Of course, if the asteroid is a Class M (Nickle-Iron), then the entire asteroid will have to be shipped back anyway, and it makes sense to move it all at once.  Two conflicts over ownership are possible here.  First, if there are multiple people using an asteroid and one of them decides to move it, the others are likely to be unhappy.  Second, if someone is moving or has moved an asteroid and others decide to help themselves, then the mover will probably be annoyed.

However, neither of these is likely to be the biggest legal and political problem to come out of asteroid redirection.  Moving large lumps of rock near Earth is likely to make people on Earth very nervous.

A small asteroid (<1000 tons) will be no big deal.  Even if by some mistake it ends up headed for Earth, it is small enough that it should break up in the upper atmosphere and cause no harm on the ground.  Larger asteroids are a more delicate matter.  There is the potential for serious damage on the ground, and everyone on Earth has a good claim on having a say in the matter.  

There is likely to be the formation of some international body that will approve asteroid redirection plans as being safe, but said body would also probably be expected to be ready to step in and make the situation safe if something goes wrong.  For medium asteroids (on the order of 10,000 tons or so) this is relatively easy to do.  This is approximately the size of the asteroid that came down over Russia in early 2013, and such asteroids are really only dangerous if they come down over a populated area, and are only particularly dangerous if they are strong enough and big enough to break up in the lower atmosphere.  Rendering them safe would involve some combination of blowing them into smaller pieces and redirecting them to come in over somewhere uninhabited, probably the ocean, which can be cleared quickly and easily.  

Beyond that, asteroids begin to become a threat to the planet no matter where they come down, and the Asteroid Guard would have to either be able to redirect them to miss completely at a relatively late stage, or require trajectories that carry no risk of impact with Earth.  The astrodynamic feasibility of such trajectories is unknown, and asteroids which are large enough to pose a serious threat to Earth are also likely to be large enough to justify shipping processing gear out to them.

It should be obvious that the Asteroid Guard would also be able to provide protection against naturally-occurring asteroids, and it would almost certainly be tasked with both roles.  

by Byron Coffey (2016)

(ed note: Ian Mallett says that the concept of a spaceguard is unworkable, and he admittedly does make a very good case for this.)

I conjecture that Spaceguard won't ever work.

Earth doesn't know where all the civilization-killing asteroids are, let alone the regionally-devastating ones. If you've found a new one, (already likely, for Belters), just redirect that and it will be indistinguishable from chance.

But let's neglect that triviality. It doesn't make sense to talk about "how many" asteroids there are in all, because it's a number that is too high to be reasonably estimated. City-obliterating asteroids (~80m diameter or so) number in the literally hundreds-of-millions, and there are exponentially more smaller ones that would still make effective weapons. There is literally no survey data on any of these, which, due to both the Yarkovsky effect and gravitational perturbations, makes their orbits utterly unpredictable. So even if we know all the objects (we don't) and can watch all of them simultaneously (we can't) for the required months (that defenders don't have), it turns out that pinning down precise orbit data is actually an impossible problem in the first place.

Leverage this with information warfare. You can plate your asteroid with mirrors to confuse estimates of its size, or tweak the computerized observatory data, or randomly perturb lots of little asteroids to waste Spaceguard resources tracking them and to disguise maliciously-guided ones. The mathematics works out so that, if the attacker plans far enough ahead, the perturbation can be arbitrarily small—and therefore unrecognizable. And you can use cold-gas thrusters or mass drivers or spread out absorbent Yarkovsky panels in key places instead of using a conventional rocket.

But mere detection isn't enough. Even without contending with dirty tricks like converting a conceivably-deflectable asteroid into a cloud-of-sand in the same orbit, or redirecting 10,000 asteroids at once using a fleet of mining drones, it's an open research problem how to deflect incoming asteroids in short periods of time. The popularly suggested "just nuke it" probably "doesn't really work", according to best evidence, since impulses are limited in absolute magnitude of momentum transfer and in any case inertia tends to fragment your target. The most (!) practical known method is to rendezvous with every single object, then deflect it. Depending on where you are in your heliocentric orbit, this may not even be possible, let alone feasible. The ΔV requirement for attacking, as before, can be arbitrarily small, but for defense (depending on how late you discover the attack), the ΔV requirement can be infinite. Because of the tyranny of the rocket equation, this means that even with perfect information, defense is exponentially more expensive than offense.

And of course, Earth-based Spaceguard is at a tremendous mass/$ disadvantage. The attacker can preliminarily target Spaceguard ships with, for example, mining outposts secret armored battle stations with tremendous heat-storage capability carved from the inside of asteroids . . .

Spaceguard, if it ever even exists, will be worse than useless. Besides the above, history has shown that when capitalism is involved, oversight is uncommon, ineffective, and unresponsive. In a mad gold-rush rapid-colonization scenario, with rocks being moved all over, there's absolutely no way the legal influence and police bureaucracy of multiple governments, let alone their infrastructure could follow rapidly enough to even try to prevent a fluke terrorist attack in those early years.

It's basically unstoppable.

(ed note: I will say that it seems like a spaceguard can be made possible if some of Mr. Mallett parameters are tweaked. For instance, some sort of legal or political interference to artificially slow down the rate of the gold-rush. Yes, most tweaks will result in an unstable situations that have temporary life spans.

Which might not be a bad thing. Spaceguards give science fiction writers a plausible excuse for the creation of national astromilitary branches. The point is that once the astromilitaries are established, the authors don't care if the spaceguards are then abolished. From the author's standpoint, they've done their job.

Or without tweaking Mr. Mallett's parameters, cynical nations might create spaceguards anyway, even though the service is worthless. It could be a boondoggle or a desperate attempt to make the illusion that spaceguard owning nations have the situation under control. Especially if they don't.

From a science fiction author's standpoint, I see a possibility for an entertaining background. Mr. Mallett notes that there is no way the bureaucracy of multiple governments could follow the gold-rush rapidly enough. Well, as an author, postulate that either this unfortunate fact was not obvious or was swept under the rug.

Initially all the governments with their spaceguards are ahead of the gold rush and everything is great. But things get tense as the gold rush starts to out-pace the spaceguard and the politicians start seeing it as a threat to their reelection bids. Draconian measures will be enacted, the corporations will push back to preserve their profits, the asteroid miners will start being squeezed and grow angry, the hustlers and chiselers will materialize out of the wood-work, and a large amount of hilarity will ensue. The situation is full of enough possibilities to provide an author with enough background material for an entire series of science fiction novels.)

by Ian Mallett (2016)
RocketCat sez

Yeah, if you look at the following two stories you'll see that Sound Decision came out in 1956 while Industrial Accident came out in 1980 with a suspiciously similar plot.

A clear case of copy-cat syndrome? I don't think so.

They are both writing about universal truths:

  • Heavy spacecraft moving like a bat out of hell are kinetic energy weapons. If they are moving fast enough they stop being mere "weapons of mass destruction" and graduate to "civilization destroying".

  • Joe Smoe on the street doesn't know diddly-squat about science, and doesn't want to learn.

  • Most politicians are Joe Smoe. Even if they are not, their constituents are. So if the politician want to get reelected they pander to their base.

  • When a civilization-threatening scientific crisis with a short reaction time happens, a lower ranking person who does understand science will be forced to break laws in order to save civilization.

  • No Good Deed Goes Unpunished.

So naturally the two stories are very similar. And very educational. And an argument for the Haldane principle.


      It was inevitable that it would happen someday.
     And it did happen … and nobody will ever know why.
     Perhaps an electron did not move from one crystal lattice to another because of a solar X-ray photon or a high-energy cosmic ray, in spite of shielding. Regardless of cause, the effect was known. The book-sized package of nucleide electronics of the autopilot and guidance system did not send the command signal to the fusion-powered pulsed plasma space drive. As a result, the space drive did not swivel, causing TriPlanet Transport’s load SLZ-420 to perform the required end-over-end skew flip to begin deceleration for eventual Earth-orbit insertion. Instead, the glitch locked out the command receiver.
     SLZ-420 had boosted away from the planetoid Pallas at a constant acceleration of one-tenth standard gravity. This doesn’t sound like much acceleration. But, at the programmed turnover point, the SLZ-420 was moving at a sun-referenced velocity of more than six hundred kilometers per second.
     Now, instead of starting to slow down on its joumey to the space factories in orbit around the Earth, SLZ-420 kept on accelerating...

     ...Man-made meteors were rarely considered as one of the hazards of the Third Industrial Revolution.
     SLZ-420 had become such a man-made meteor. It was nothing more than a solid cylinder of planetoid iron fifteen meters in diameter and twenty-three meters long, weighing a mere thirty-five thousand tons … a grain of celestial sand on the beach of the solar system.

(ed note: currently with a kinetic energy of 6.3×1018 joules, about 1.5 gigatons)

     The glitch in the electronic guidance system had not affected the instructions to "go to Earth" that had been implanted in its memory on Pallas. Faithfully, it continued to do its job … except for that one little program step. Faithfully, the reliable constant-boost space drive continued to work, adding one meter per second to the velocity every second … in the wrong direction. Toward Earth. Toward eight billion people aboard a giant spaceship living in an ecology that was vulnerable to the man-made meteor. Toward people who were ignorant of SLZ-420 and who did not understand the consequences of what could and would happen. But., also, towards people who had not ignored the possibility that it would indeed happen someday.

     The House committee hearing room had not changed in nearly a hundred years. Established behind his elevated desk with the status symbols of the microphones before him sat a man who was almost indistinguishable from most of his predecessors. Representative Claypool Evans Perrin had served the people of his district for nearly a quarter of a century … or so they believed. However, he knew full well that politics was simply the interaction of various power groups … and thus he had remained in office through twelve election battles. He scorned implant lenses, preferring old rirnless eyeglasses. He felt that they lent a distinctive touch to his craggy face toppediby its famous shock of unruly hair, hair that was now pure white and wom long in the romantic fashion of the ancient seventies. Perrin believed it helped maintain his image as a young-thinking firebrand radical, the image that had served him well for all those years and all those elections.
     He peered now through those spectacles and fixed his stare on the man behind the witness table below him. “Please let me get this absolutely clear in my mind, Mr. Annitage.” He spoke in the measured cadence of his rasping voice. “The Control and Inspection Division of the Department of Space Commerce is requesting a budget line item of 4.7 billion dollars for something you term an ‘emergency accident system.’ If I understand this correctly, it’s for the development and deployment of interceptor-type space vehicles based at L-5.”
     Chuck Armitage was quick to attempt a reply. “Yes, sir, we—”
     But Perrin wasn't about to let the witness speak yet. “Under the terms of various United Nations treaties, some of them more than fifty years old, no nation is permitted to maintain any soit of deep-space military system beyond that necessary to police its own space operations … sort of the equivalent of the old Coast Guard, if you will. We’ve spent billions of dollars to ensure that the Space Watch can defend our national airspace up to a hundred kilometers, as we are permitted to do under intemational agreement.” He paused and shook his long white hair out of his face. “Mr. Armitage, isn’t the Department of Space Commerce asking Congress to let you build an armed force based in space and capable of carrying out offensive military acts against space facilities as well as against Earth?”
     It was a loaded question, and Chuck Armitage knew it. Hunching forward over the witness table, he looked intently back at Congressman Perrin while he collected his thoughts and tried to choose his words very carefully. His thinking processes were quite rapid in this environment because he had fought his way through many congressional appropriations hearings in the past.
     ‘ ‘Mr. Chairman, the department can’t do what you are claiming, as Secretary Seton has said many times. The intent of the budget line item request is quite different, and this is why Secretary Seton has asked me to speak for it in her stead. As head of the Control and Inspection Division, I am the policeman of our space commerce activities and—”
     “I have read your vitae, sir—” Perrin broke in, apparently with impatience. It was, however, a technique that he used very effectively with witnesses. But it didn’t work with Chuck Armitage.
     “Then you know what sort of situation I am faced with on a daily basis,” Armitage broke in himself. “In fact, for the past twenty-two years we have lived with the situation since the Whitney Drive was first used for constant-boost spaceflight…
     “Ah, yes, but for those twenty-two years, there have been no problems that space crews have not been able to solve.”
     “Those were manned vehicles, Congressman,“ Armitage pointed out. The exchange was becoming rapid-fire as both men tried to gain and maintain control of the situation.
     “What possible difference does that make?”
     “Problems could be solved in transit. But things have changed. The majority of cargo vehicles today are unmanned because of various govemmental restrictions—not in our department, by the way—that prevent the necessary capital accumulation required to finance manned ships.”
     “Well, such rules pertaining to the regulation of space commerce are not the province of this committee!”
     “No, sir, but the unmanned cargo ship is a consequence that we must deal with here. The solar system is full of unmanned ships right this instant, some of them boosting at more than a standard g. I am responsible for the safe operation of those ships of United States registry. And I am especially worried about the unmanned, automated vehicles. There is a finite chance that something could go wrong with an unmanned ship … and we would be faced with the prospect of a very large mass coming at us with terminal velocity approaching a thousand kilometers per second … In effect, man-made meteors. ”
     Perrin waved his hand. “That seems to be a rather remote possibility. Meteors have been hitting the Earth for millions of years. The government of the United States has never had to concern itself with any problems of protecting its citizens against falling meteors!” A titter of laughter ran around the hearing room. Perrin felt that he had counted coup on that one.
     “We are not talking about natural meteors, Mr. Chairman! Most of the natural meteorite material out there is no bigger than a pebble … or somebody would be mining it right now! We are concemed with a recent man-made phenomenon: un-manned constant-boost cargo ships. There are more than a hundred of them boosting toward the Earth-Moon system right now. We need only one failure—one faiIure—to have a worldwide catastrophe on our hands.”
     Come, come! I have never known you to exaggerate in your testimony before, Mr. Armitage. Worldwide catastrophe? Really!"
     “I wish it were not possible, Congressman. We estimate that the impact of a a thirty-thousand-ton planetoid ore carrier at five hundred kilometers per second would produce an effect equivalent to several hundred megatons of TNT (I calculate it as being closer to one gigaton, but who's counting?). But the scaling lafws break down because we cannot extrapolate from the results offearly thermonuclear warhead testing. The United States set off a ten-megaton thermonuclear device in 1952, and the Soviets blew off a fifty-megaton nuke shortly thereafter We are not sure that—”
     Perrin cut in again. “We’re not discussing military warheads Mr. Armitage”
     "No sir, but we are discussing the rapid release of large amounts of energy — and the only difference between a large nuke and a fast-movmg rock is the lack of radiation from the rock impact. In addition, when a large unmanned ship hits, it will be moving many times faster than a natural meteor, and its kinetic energy increases as the square of—”
     "Mr. Armitage. isn’t your division responsible for seeing to it that a runaway spaceship could never occur? Aren’t we discusing something so highly hypothetical as to be ridiculous. Aren't your people on top of the safety aspect?”
     "Yes, sir, they are. Our specifications and technical directives must be followed bv all manufacturers and users of equipment licensed or registered by the United States. By international agreements, all other spacefaring nations either adopt our rules or have rules that are compatible. Our field representatives inspect and sign-off all new equipment as it comes out of the factory door. They do the same for all routine maintenance, overhauls, and even for preboost checks.”
     Then what is it that could possibly go wrong Mr Armitage?"
     "Mr. Chairman, no technology is ever perfect. We are not gods; we are people with a very incomplete understanding of the way the universe works. Sooner or later no matter how diligent we are and no matter how exhaustixeour tests something will misbehave. Let me state categorically—and I’ll back it up with numbers at a later time if you wish—that there is a statistically valid possibility that the Earth will be impacted by an unmanned multithousand-ton cargo ship within the next ten years. We must have an emergency system of long-range deep- space interceptors — a dozen is all that we are asking for. They would be based at our L-5 facility. They have to be because of the negligible gravity well there and because of the fact that it is easier to intercept a runaway ship as far out as possible — and not even very easy under those conditions.”
     Perrin leaned back and made a steeple of his fingertips.
     “Isn’t the Space Watch prepared to take care of such matters?”
     “Ask the Space Watch.”
     “But I am asking you, Mr. Armitage."
     "The Space Watch interceptor force is Earth-based by treaty. The beam weapons at L-5 have limited power under the SWAP agreements with the Soviet Union, whose L-4 beam weapons are also limited. Ask the Space Watch, sir, because they are well equipped to handle defense against Earth-launched missiles or against anything the Soviets might try to do from L-4.”
     “You haven’t answered my question, have you?”
     “I cannot answer it in open session, nor am I privileged to know all of the sensitive details of the Space Watch systems.” Chuck Armitage did know these details. He wasn’t supposed to. He wasn’t cleared for that information, but he had his channels of information that were zealously protected. He had known for five years that the Space Watch did not have the capability to even deflect the course of an unmanned runaway. “This is why I suggested, Mr. Chairman. that you might ask the Space Watch to —”
     An aide leaned over Perrin’s shoulder and whispered something into the congressman’s right ear. Perrin nodded and glanced at his old-fashioned digital wristwatch. He turned his attention again to Annitage. “We have an important roll-call vote coming up in a few minutes. So we’ll not have time to discuss this further today. We may have a duplication of effort conflict arising between DSC and the Space Watch. The fine line of division between military and civilian utilization of space has been a major problem for nearly sixty years, and I doubt that we will find the solution to it today.” Perrin decided that he would mention the matter to the presidents of TriPlanet Spaceways and TransWorld Transit at dinner that evening to find out if there was any support for this program from the space transportation lobby…

     …"Too damned many things in space operations have been determined by political compromise rather than by technical or economic realities," Armitage continued to mutter. “I once thought that when private enterprise became involved, it would be the end of the political football game … but they just started playing again with new rules…"

(ed note: Armitage is told about the runaway ship SLZ-420)

     Chuck Annitage had a decision to make. and he waited until the very last moment to make it. In one smooth motion, he reached out and picked a telephone handset out of its cradle. When he punched the call buttons, his motions were sharp, rapid and almost vicious. “Tom, Chuck Armitage. It’s a ‘go’ situation. my friend. Let me know whether you or Kim decide to be number one. … Yes, it will be messy … I’ll take care of that. … Good luck, Tom … and arigato.” He put the handset back in its cradle softly. For minutes, he stared straight ahead at nothing…

     …Over the next thirty minutes, his guests arrived. Some were indignant. Some were quizzical. Some were somber. None of them knew the full story, some of them had snatches of data that they had agreed would not be discussed until Chuck had given them a full briefing, but almost all of them sensed that there was an aura of quiet, controlled, constrained terror in the air.
     “I’m sorry I interrupted your dinner, Congressman,” Chuck tried to apologize to Perrin. '
     Perrin’s reply was a growl from an important man who has had his arm twisted. “If it hadn’t been for Senator Davidoff, I would have considered this whole matter as a grandstand play resulting from the hearings. I’m still not certain that I …
     “Chuck Armitage does not make grandstand plays,” the young senator cut in. “I've know him too long to …”
     “How do we know this isn’t a dry run?” Perrin wanted to know.
     “I wish to God it were a dry run,” was Chuck’s reply. Raising his voice above the conversational hubbub of the room, he announced, “Please take a seat, everyone. I want to tell everyone what’s going on here.”
     Most of the people in the room knew one another … Star Admiral Jacobs, top man of the Space Watch; Joseph Hirschfeld of TransWorld; Andrew Watermann of Terra-Luna Transport; Jeremiah Morris of TriPlanet; foreign liaison professionals from Europe, Japan and the Soviet Union; and Secretary Helen Seton, secretary of the Department of Space Commerce with the gleaming Distinguished Space Star pinned like a brooch to her high-necked tunic covering the scars and prosthetics from the power satellite accident.
     “Ladies and gentlemen, you are here at the request of the president of the United States, who is fully aware of the crisis that now exists,” Chuck began. “George, please get the rest of the teleconference on the line. Now, to anticipate some objections conceming national security, I wish to further tell you that I am acting with the full authority and approval of the president in establishing this hologram teleconference with our compatriots in Europe, Singapore and the Soviet Union. Please stand by until George completes the circuits."
     The side wall of the room disappeared, revealing three more rooms similar to the one they were in. In each of the shimmering three rooms, the holographic projections from Europe, Singapore and the Soviet Union flickered into being as the circuits through the geosynchronous comsat platforms were given a final tuning. Brief greetings were exchanged, but they were short. The holographic participants seemed to know what the situation was, and they were all business.
     “We have a crisis on our hands with worldwide implications,” Chuck announced. “Our colleagues elsewhere must participate on a real-time basis. A space vehicle of United States’ registry has become a runaway, and it may impact Earth …”
     The room exploded with voices.
     “Gospodin Armitage,” the Soviet hologram spoke, causing the room to become quiet, “is it as bad as our information indicates to us?”
     Chuck nodded. “Here are the full details. TriPlanet cargo load SLZ-420 running in from Pallas at thirty-five thousand tons gross weight did not execute turnover at 17:10 Universal Time today. Because of the distance involved, our tracking net did not leam about this for almost two hours. Neither we nor the people at TriPlanet know what is wrong. Telemetry indicated that everything aboard SLZ-420 is operating normally, but the autopilot will not acknowledge nor execute commands. This should not happen with triple-redundant circuits, but it has.”
     Luxemburgwanted to know, “What is the inspection history ?”
     "Our records and those of TriPlanet indicate that all systems have undergone periodic inspections as required and that all spacewonhiness directives have been complied with. Our Pallas field office gave clearance to boost based on an affirmative preboost check.”
     “Can we compare computer data?” the Soviet asked.
     “Of course," Chuck said and noticed that Star Admiral Jacobs flinched slightly. “Call it up on our standard data transfer net. You can also get the graphic presentation we have on the walls here at center. At turnover, velocity was 612 kilometers per second, and it is still boosting toward us at one-tenth standard g. That doesn’t sound like much, but it is adding one kilometer per second to its velocity every sixteen minutes and forty seconds.”
     A few people in the room were rapidly keying display consoles, calling up additional data. But most did not know how. They sat there, responsible for the use of the technology, but unable to manipulate it.
     Senator Davidoff broke the silence. “But it doesn’t seem to be boosting wild. According to the shape of the trajectories you‘re plotting on the walls out here, its guidance system seems to be working."
     "Working perfectly and homing on Earth,” Chuck told him.
     “Have you alerted the Space Watch?” It was the first time Perrin had spoken since the briefing began. “Can they stop it?”
     Chuck indicated the star admiral.
     Jacobs was young, but he was both a competent engineer and an experienced leader. He first looked directly at the hologram of his Soviet counterpart. Then he turned to Perrin. “No,” came the flat answer.
     “But you’ve got an interceptor force!" Perrin complained.
     Jacobs glanced at the Soviet hologram. “I am not free to discuss it.”
     Chuck picked up a telephone. "As Secretary Seton can verify, the president has authorized complete cooperation and the total lifting of security restrictions. Shall I call him to satisfy you?” ,
     Jacobs hesitated.
     “Since we began this teleconference, SLZ-420 has added one hundred fifty meters per second to its velocity, Admiral,” Chuck pointed out, holding up the telephone. “Do you want me to get the president on the line for you, or are you willing to accept what I tell you?”
     Jacobs looked at Secretary Seton. “I spoke with the president,” she said quietly. “Speak freely, there is no security barrier.”
     “Our interceptors are Earth-based according to treaty. We’ve built some slight excess performance into them so that we could operate them de-rated,” Jacobs rationalized. “With a very great deal of very good luck and everything working perfectly, we might intercept with a nuke at a range of three hundred kilometers from Earth. But at that point, the SLZ-420 is moving at eight hundred kilometers per second … and those rates are beyond … are beyond the capabilities of … of our intercept system.”
     “You have exceeded SWAP treaty limitations!” the Soviet hologram objected strongly.
     “Gospodin!” Chuck snapped. “I would be very happy now if you had exceeded them to a greater extent!”
‘     “Burn it with your beam weapons at L-5 !” Perrin suggested.
     “Congressman,” Jacobs told him, “those beam weapons won’t make a dent in thirty-five thousand tons of iron! By treaty, they’re defocused beyond four hundred thousand kilometers. We can refocus them in about four days’ time … which is several days faster than I know my Soviet counterpart can manage. But even if we could refocus, we haven’t got enough time to input enough energy into the target. At the velocity it will be moving, it will take only seven minutes from time of crossing the lunar orbit until it impacts.
     “Mein Herr, do you have an impact prediction yet?” was the question from Luxemburg Center.
     Chuck paused to key a terminal. “Here’s the latest update, Fritz. Barring any malfunction of the SLZ-420’s guidance system, which is unlikely, the ship will impact near Genk, Belgium, in fifty-nine hours and approximately ten minutes from now. Entry velocity is estimated to be 867 kilometers per second, which means that the Earth’s atmosphere will have negligible effect on its mass from ablation or on its impact velocity. The impact will release kinetic energy equivalent to a 284-megaton bomb … and we do not know what the effects will be. The atmosphere shock wave will rebound around the planet several times, and the ground shock will certainly go off the top end of the Richter Scale. Some of the thirty-five thousand tons of iron will vaporize on impact, and some of it will get tossed clear around the planet as secondaries … some of which may pose a problem to near-Earth orbital facilities. Other than the brief burst of hard X-rays from the atmospheric entry plasma sheath, there will be no radiation other than heat … and the fireball of impact will probably rise to the top of the stratosphere and squat there, radiating most of its heat to space. The meteor experts at Flagstaff couldn’t even guess the effects on the planetary weather…
     “Is there any chance it may go into the Atlantic Ocean instead?” the hologram that was Fritz in Luxemburg asked.
     “That just makes it worse,” Chuck pointed out. “The impact might vaporize enough sea water to create a worldwide cloud layer … which in turn could raise the world temperatures by several degrees by virtue of greenhouse effect… Look, all of you, I just don't know everything that could happen because we have never experienced anything like this in all recorded history! We can’t even extrapolate from fairly recent strikes such as the Barringer Crater in Arizona … which was made by a small slowpoke in comparison to SLZ-420… ”
     There was complete silence for moments as the full import of the information sunk in. It was Claypool Perrin who lost his cool. “We've got to start evacuation of the impact area!”
     “Clay,” Davidoff said, “an announcement would start a panic.”
     “But millions of people will die! How can you just sit here and let the sky literally fall on those millions in Europe without telling them?”
     “Congressman, will you provide me with some guidelines on how to evacuate a whole continent?” Chuck said.
     “But you’ve got to do something!” Perrin exploded. “How can you sit here and watch blinking lights and program computers and let the world come to an end? This is madness! You’ve got to do something!”
     The people in the room. including the holographic projections, were now looking at one another, often with quick glances, sometimes with long eye contacts. Nobody said a word. Most were afraid to say anything.
     Slowly and softly, Chuck broke the heavy silence. “I have already done something about it.”
     The room exploded again in voices. Chuck merely held up his hand, and the room fell silent again. Of all the powerful people in the room, Chuck Armitage was now the most powerful. He turned around and pointed to a screen in the traffic room. Two green triangles were now leaving a green trail on the near-Earth display. One of them appeared to be accelerating rapidly. The display had been up for several minutes, but only Chuck had noticed. The others had been far too engrossed in the problem or did not understand the display.
     “Madame Secretary,” Chuck addressed his boss who, because of her astronaut training, had maintained her cool consideration of the affair. “You know nothing of what I have done. I haven’t told you about its planning. I initiated its implementation without your knowledge or approval. I utilized funds from several parts of the budget in such a way that the expenditures wouldn’t be noticed until GAO audits us. I’m sorry that I had to do it this way, but I had to protect you and the department from the storm that is to follow. I accept full and complete responsibility. ”
     “You still haven’t told me what you’ve done, Chuck,” Helen Seton pointed out with no trace of emotion.
     “First off, here is my resignation, effective immediately.” Chuck withdrew an envelope from his jacket pocket and proffered it to his boss.
     “We’ll discuss it at a later time when things are not so critical,” she replied with a wave of her hand, refusing to accept the envelope. What is going on now?” she asked quietly.
     “My grandstand play. Senator Davidoff said a few minutes ago that I don’t make them. That is not precisely true. I don’t make them until it counts. If I had yelled and made a bloody nuisance of myself over the runaway possibility when I took over here seven years ago, I would not have remained in the position for more than six weeks … ”
      “That’s a very astute observation, Chuck,” Davidoff told him.
     “I know. Jeremiah, your people, combined with those from TransWorld and Terra-Luna, would never live with any system that could reach into deep space. Neither would the League of Free Traders—”
     “Don’t try to put the blame for all of this on us, Armitage ” Jeremiah Morris growled. “Because of your unreasonable regulations. we've had to put safety devices on the satety devices … and something was bound to go wrong sooner or—”
     “Gentlemen!” Helen Seton’s voice was still quiet, but it carried both leadership and authority in its tone. “Please! There will be ample time for bickering later … if we survive. Let Chuck explain what it is that he has done behind the scenes."
     “Thank you. I did a bootleg engineering job that is something far less than perfect with high risk involved and exorbitant ultimate cost … hoping that I would never have to use it because others might be convinced to give us the means to do it right. Well, SLZ-420 forced the issue and pushed me into using my Plan B which is one-shot. We can never use it again, so we’ve got to get our heads together even while it is probably saving our necks … which is why the president acceded to my requests to bring you together here.”
     Perrin was on his feet, using his full-volumed House speaking voice. “I will not permit myself to be pressured in this manner. … Please excuse me!”
     “You will have some trouble getting out of here, Chuck Armitage pointed out. “Madame Secretary, do I not have the authority to seal off the center in an emergency?”
     “You do, and I will not countermand your order. But would really like to know what you are doing, Chuck. All of this preamble obviously seems important, and it probably is. But SLZ-420 is coming down our throats, and that is Priority Number One. Will everybody please be quiet and listen?” When she raised her voice with emotion in it, the shock rippled through the room, which instantly became silent.
     Chuck spun a chair around and literally fell into it. Fatigue was beginning to get to him, and there was a long time yet to go. “Those two green triangles boosting hard away from Earth are two of our deep-space inspection cutters from Hilo base, Hawaii. They have been highly modified and each is manned only by a single pilot.
     "Manned? Why manned?” Star Admiral Jacobs wanted to know.
     “Because we had neither the time nor the money to develop the necessary long-range active guidance and homing sylstems that are required for an interceptor that can, handle high closure rates at distances far beyond lunar orbit”, Chuck explained. “I had to use a guidance system that was already available: a human being. The first triangle represents the cutter Toryu, which is boosting at four standard g’s, the limit of sustained human endurance, under the control of Tomio Hattori. The second triangle represents the Shoki, boosting at two standard g under the control of Kimsuki Kusabake. In approximately twenty-five hours, the Toryu will intercept the SLZ-420. If Tom Hattori does the kind of job I know he can do, the impact of that two-thousand-ton cutter will do one or both of two jobs: deflect the SLZ-420 from its present trajectory and/or disable its constant-boost drive. If Tom doesn’t do the complete job, we have the Shoki following with Kim to finish it off … but that will be a tough one because of the increased closure rate …”
     Again, it was Congressman Claypool Perrin, the reelected romantic of the let-it-all-hang-out seventies, who broke in almost hysterically. “Do you mean to tell us that you have deliberately sent at least one person to a certain death? How can you possibly do this … this inhumane thing?”
     “I know of no other way to do it at this time with the tools that you have permitted me,” Chuck fired back. “And spare me the outrage. Ain’t nobody here but us chickens, fellas … and that is an American folk saying for the benefit of our teleconferencing guests. Every one of us in this room, including the teleconferencing guests, has contributed to this situation in his own unique way.”
     “Now, that certainly isn’t true, Chuck! This should have been a Space Watch job—” Star Admiral Jacobs started to say.
     “See what I mean?” Chuck said. “The Watch fought us tooth and nail when we instituted orbital sweeping for the thousands of dead satellites up there. No, they wanted high-power beam weapons installed in L-5 to do the job … And I know that your intelligence people knew that, Dimitri!”
     “That’s not a fair assessment!” Jacobs tried to break in. “The State Department didn’t—”
     "I don’t care who tries to put the blame on who!” Chuck said in exasperation. “Govemments, private enterprise, everyone involved in space commerce is right here. right now! Reading it on the news tube wouldn’t have helped toward a solution; you had to be here right in the middle of it living with the consequences of your actions. You had to see and experience it, and it is a very difficult thing to do. And please don’t think that taking care of this industrial accident was an easy thing for me to do, either!” He sighed deeply and rubbed his eyes. “But it will be an easy thing for Tom and Kim.”
     “What do you mean. Chuck?” Senator Davidoff asked.
     “Admiral Jacobs knows what I mean. There are always people who are willing to sacrifice themselves for the greater good. Some people seek self-destruction for a cause in order to give meaning to their lives. Our psychologists can spot them. And sometimes it is a cultural trait…
     “Kamikazes,” Jacob muttered.
     “Over two thousand pilots of World War II, and several thousand from time to time since then in suicide missions in brushfire wars for a glorious cause greater than they believe themselves to be.” Chuck noticed that Perrin was now shaking his head in total disbelief. “No, Congressman Perrin, this job isn’t all technology. It deals with people because technical problems are rarely unsolved due to technical factors. In this case, I am giving two people the opportunity to fulfill themselves. Tom and Kim are out there by their own free choice. I have been the only one who did not have a real choice.”
     Most of the people present in the room sat aghast, with three exceptions—the hologram from Singapore whose Japanese features indicated full understanding, Secretary Helen Seton, whose own sacrifice on PowerSat One had made her life as a woman and mother impossible, and Star Admiral Jacobs, who nodded as though he had discovered in Chuck Armitage a man he could fully understand. “We have them in the Space Watch, too. No military establishment could exist without them,” he said with pride.
     It was now very quiet in the room again. Armitage looked around. “We have twenty-five hours before we know if Tom Hattori succeeds. In the meantime, we have placed the tightest possible worldwide news lid on this. There will be no leaks from Singapore or from the centers. Food and beverages will be available here, and there are secure rooms down the hall if anyone needs to rest. Your respective organizations have been notified that you are in a special international conference, which is no lie. We have all seen the consequences of our past activities. We now have the unique opportunity—to work out an arrangement so that this sort of thing can never happen again. Madame Secretary, you are the logical one to chair this ad hoc conference. Would you care for some coffee?"

     Tom Hattori and the Toryu did the job. The haggard group in the gallery of the center watched the displays as what was left careered around the Earth and plunged outward forever into deep space with a velocity that would take it to the stars. There were no cheers. The conference group was far too exhausted physically and emotionally. New agreements had been hammered out. A joint communiqué had been written and released to the news media.
     Both in space and in the center, the solutions were compromises … but workable compromises.
     Chuck Armitage was the first to leave the center.
     He discovered Senator Davidoff and Secretary Seton walking on either side of him.
     “Where are you going, Chuck?” Helen Seton asked.
     “Home. To stay.”
     “Take a few days’ rest. Then come and see me. There’s work to be done … lots of work.”
     “Madame Secretary … Helen … my resignation holds. It has to.”
     “Chuck, you’re a good man,” Senator Davidoff put in. “We’ve always needed good men. Why do you think you’re finished in your present position? With the new agreements, we need you more than ever. You were the spark plug that got it all together for us.”
     "Ah, my dear colleague from the good old days of the Shuttle missions!” Chuck Armitage replied. “Perhaps you and Helen can handle the political aspects of this and swing enough clout with GAO so that Justice does not indict me for misappropriation of funds …”
     “But you saved the whole damned world!” Davidoff pointed out.
     “Temporarily … until the next crisis in an era of crises.
     “I can’t be as dramatic as the senator,” the petite secretary of space commerce remarked, “but he’s right. We need you more than ever. When forced to make a decision, you didn’t waffle … and it was a very tough decision. Both the senator and I know such a thing is rare among people today, but absolutely necessary in space. Chuck, your career and job are not in jeopardy. I’ll stick by you, whatever happens …”
     “And I will do the same,” Davidoff added quickly, earnestly.
     Chuck stopped walking so suddenly that his two companions went two steps beyond him, then turned to face where he stood. “No. For several reasons. You’re on top of the hill, and I am down on a ridge. I see some things differently. I pushed around a lot of internationally powerful and influential people. I rubbed their noses in their own accumulated folly and made them admit to it by forcing them to come up with a new set of rules. I’ll never be one of them and I’ll no longer be able to work for them because I have proved that I am willing to rock the boat and make big waves. I am no longer to be trusted…
     “Nonsense!” Davidoff snorted.
     “You know it isn’t. I cannot ask you to risk your own careers. I’ve already sent one man to his willing destruction; I cannot ask anyone else to even risk it. In fact, my own personal values are making it very difficult for me to rationalize Tomio Hattori. In my own case, it doesn’t count. When I spoke of people willing to sacrifice themselves for a greater cause, I knew exactly whatl was talking about… Now, please excuse me. I’m very tired…”
     He turned and took a side path, walking away from them. In the star-specked evening, the ex-astronaut senator and the ex-astronaut minister watched him go. There wasn’t anything either of them could say.

From INDUSTRIAL ACCIDENT by G. Harry Stine (1980)

(ed note: The interplanetary passenger liner Martian Queen had a little accident. Right before the scheduled flip-and-burn to decelerate, the nuclear converter in the engine room explodes. This turns the converter into radioactive slag, vaporizes the rocket motors, and of course kills the four engineers.

Of special concern is that the ship has a velocity relative to Terra of 32 kilometers per second, the ship has a mass of 500 metric tons, and has 184, sorry 180 living people on board. Yes, that's 2.56×1014 joules since at that speed it has 114 Ricks. About the same number of joules as seven Hiroshima atom bombs rolled into one.

Oh, and it is heading right at New York City. It will hit in about half an hour.

Captain Deering frantically checks all his options but there doesn't seem to be any. )

(ed note: meanwhile at White Sands Spaceport with General Neil Stanley commanding)

      Stanley picked up the phone. "Stanley here.”
     "General, we’ve got the fix on the Martian Queen.”
     "What’s the ETA?" Stanley asked.
     There was a pause at the other end of the line. "We haven’t computed the ETA, sir,” the voice said hesitantly. "There’s something wrong. The position is off, and the velocity is constant. The —”
     "Never mind,” Stanley said, cutting the man off in mid-sentence. "I’ll be right over.” He slammed the receiver down and pushed the phGne away.
     He left his office on a dead run, his lips clamped together in a grim scowl. When a radar fix can't compute the Estimated Time of Arrival of a spaceship instantly, there is something wrong—deadly wrong...

     ..."Never mind," Stanley said crisply. "Time to talk later.” He pushed back his cap and walked past them without bothering to ask questions.
     "Chart,” he murmured.
     They complied. Stanley looked at the blip on the scope and checked the reading against the chart, frowning worriedly. Something was definitely wrong; the blip wasn’t moving, which indicated a constant velocity. The Queen should have started decelerating long before this.
     A bead of sweat trickled down his heavily-tanned forehead, and he brushed it away impatiently. The data was there. The Queen wasn’t decelerating. Why? Who knew? Who cared? All that mattered was the bare fact.
     "Get me a direct line to Captain Deering!" Stanley said sharply, without looking up from the charts.
     "Yes, sir,” Sokolow said.
     Stanley rubbed his chin. The ETA charts were simplicity itself. The readings on the screen could be checked against the charts and the time for landing was right there; the figures had been computed long before. All the radar man needed to know was the ship's position, velocity, and negative acceleration.
     But this ship was off position and had no negative acceleration, and the charts weren’t set up for a situation like that. Preconceived rules are nice things to have, but they simply don't work in an emergency.
     While the radio man upstairs tried feverishly to get a direct communication to the Martian Queen, Stanley reached across the desk, pounced on the phone, grabbed it toward him, and dialed Routing.
     "Stanley here. I want a computation fast.” He glanced at the screen and rattled off the bearing, velocity, and direction of the blip on the radar. "I want to know when and where she’ll hit if she doesn’t decelerate. Got that?”
     When and where she'll hit. He said the words in a clipped, businesslike manner, concealing the feeling that lay behind them. It was impossible for him to get hysterical over the situation, but he certainly appreciated its ugliness. Spaceships are big, heavy things, traveling at fantastic speeds, and a man who had worked with them half his life knew' exactly what potential danger each one carried...

(ed note: on board the Martian Queen)

     ...Captain Deering’s jaw muscles tightened as he heard the words coming over the intercom.
     "Hagerty here. The engine room’s a wreck, captain. I sent Palmer in, but he couldn’t stay long; it’s too hot down there. We didn’t find out much.”
     "What about the main converter?” Deering asked anxiously.
     "Almost completely gone. It’s a wonder it didn’t blow into fragments when it went. God only knows what happened. The engine crew’s gone — died almost instantly, I'd guess.”
     "What’s the converter like?” Deering asked. He’d long ago forgotten about the lamentable but irreparable death of his engine crew; the important thing now was getting the engine room back together, not giving the four men a proper burial. That could come later—if there was any later to come.
     "The converter’s a mess,” Hagerty said. "Mostly molten metal, according to Palmer, though it’s beginning to solidify now. The shielding has kept the radiation from the rest of the ship, and it’s slowly dying out now.”
     "And the engines?” Deering asked, knowing that only a miracle could have preserved them. "Any chance of starting them?”
     "What engines?” Hagerty’s voice told the story without need of further explanation. "There aren’t any engines left to start.”...

     ...He turned away from the intercom and grabbed the radiophone, feeling as if there were cannons to the right and cannons to the left of him. "Deering here!” he barked. "What do you want, Neil?”
     "Buddy? Stanley here. What’s going on up there? Man, you've got to stop that thing!”
     Stanley’s voice held an ominous, imperative ring. Deering grinned sardonically. "Any suggestions? Black magic, maybe?”
     "What’s the trouble?”
     "Main converter shot all to hell, and so is the secondary. Engines out. I’m just getting moving on the thing. What’s our course?”
     Stanley's voice was harsh. "Never mind now. What happened ?”
     "God knows!” Deering said. "We'd just stopped spin for deceleration and something blew in the engine room. We’re powerless. Hagerty says there’s nothing but slag down there!”
     Stanley was silent for a moment, and Captain Deering stared impatiently at the radiophone in his hand. He felt a little better about things now that he knew Stanley of White Sands was with him. There was something reassuring about contact with the big catlike man, even when you were riding a spaceship straight to hell and he was sitting down there comfortably in an air-conditioned turret.
     "O.K., feed me your co-ordinates,” Stanley said at last.
     Deering glanced up at Lieutenant Blivens. The prune-faced astrogator was standing by tensely. "Course,” Deering demanded.
     The astrogator threw him a sheet of paper, from which Deering read figures. "That's as close as I can get,” he said, when he was through. "Do you have a fix on us?”
     "Checking it now,” said Stanley. "I’ve got some other things to do right now, but keep the line open. Off.”...

     ...The words were futile. The Martian Queen was falling toward Earth—powerless. Deering took the situation in, and he knew there was little sense in ordering Hagerty to work a miracle. There was nothing in space that could save the ship...

(ed note: at White Sands Spaceport)

     ..."What’s happening to that data?” he asked.
     "Coming out now, sir," someone at the other end said. "We fed DIRAC the figures you gave us. They’re not too accurate, but—Wait! Here it is now.”
     There was a long silence at the end of the line, while Stanley chafed his fingers impatiently together. "Sir!” came the voice finally. "They aren’t going to miss Earth!"
     "What? That checked?”
     "Yes, sir. Whatever happened, it threw them off course just enough so that they’ll still crack up on Earth even if they don’t decelerate. It’s a million-to-one fluke that they should be—”
     "Can it,” Stanley said. "What’s the intersection point of the two orbits?”
     "Somewhere along the East Coast, sir. We can’t get it any closer than that without more precise data. I’d say that it’ll hit somewhere near New York City if it doesn’t slow down !”
     "It figures,” said Stanley tightly. "It figures. How long before she hits?”
     "A little better than a half hour, sir. Can you get us more accurate data?”...

     ..."Experimental!” Stanley ordered. "And double quick.” The jeep roared off across the compound toward the Experimental Drive building.
     Almost before they had started, they were there. The jeep's wheels had barely stopped moving when Stanley sprang out of it and toward the building.
     Colonel Arthmore jerked his head up in surprise as the major general slammed into the room. The colonel didn’t even have time to give a proper salute before Stanley said:
     "Is that XV-19 ready to go? Can we have it in space within the next twenty minutes?”
     The colonel blinked and nodded. "I think so, sir, if we rush it. We—”
     "Rush it, hell!” Stanley snapped. "I want you to move faster than that ship can. It’s the highest acceleration ship we've got, isn’t it?”
     "Yes, sir! We—”
     "I want it ready to leave inside ten minutes. Take that as an order!”
     "Yes, sir.” The colonel had fully come to life now; he’d been galvanized into the same sort of quivering perpetual motion that was driving Stanley right now.
     "And I don’t want a word of what’s going on to leak out of here,” Stanley said. "Is that understood? If one word leaks, or if that ship isn’t ready to go. I'll see to it that you’ll never wear those birds on your shoulder again. Is that clear?”
     "Yes, sir,” said the colonel. "Anything else, general?”...

(ed note: at an emergency meeting General Stanley gives a briefing to civilian leaders )

     ...One of the civilians—no one had bothered to tell Stanley exactly which high-level members of the Administration he was dealing with—said, "Is there any way at all to get the drive of that ship going again? Don’t they carry repair technicians, or something like that?”
     "I have Captain Deering’s report,” Stanley said. "He states flatly that the main converter and the secondaries are absolutely and completely ruined. It would be, I assure you, impossible to fix them in the next fifteen minutes, even with the best intentions.”
     The civilian ignored the sarcasm. "Well, how about a rescue ship? Couldn't we get one up there in time to take those people off?"
     Stanley paused and said, "Sending up a rescue ship is impossible, sir.”
     "Why’s that?"
     "It would never make it. They would have to accelerate to take off, decelerate to match velocity with the Queen, and then accelerate again to keep from hitting Earth. Counting the time it would take to get all the passengers and the crew off of the Queen, it would require”—he made a rough mental computation—"more than an hour, even if we used all the acceleration the passengers could stand. I'm afraid it won’t work."
     General Hagopian said: "Then there's absolutely no way we can save them?”
     "None whatsoever, sir. There just isn’t time.”
     Another of the civilians said: "We’re just lucky this time, I suppose.”
     "What’s that?” Stanley asked.
     "I mean, it’s too bad all those people have to die, but at least they’ll only hit the Sound. It would have been catastrophic if they’d hit a populated area. Only by the merest whisker of fate did that ship aim for the Sound instead of any of the cities on the Eastern Seaboard! Can you imagine what would have happened if the ship had landed in—”
     "I’m afraid you don't understand, sir,” Stanley said. "It isn’t the Sound we have to worry about—it’s the sound.”
     The five men blinked.
     "What nonsense is this?” asked General Hagopian.
     "Just exactly what I said, sir. It doesn’t matter whether that ship lands in the water or not, because it’s never going to land in one piece anyway. That ship is coming into Earth at twenty miles per second. When it hits the atmosphere, it’s going to go to pieces in a hell of a hurry. It will burn and collapse. "But its actual impact with Earth’s surface isn't going to be the thing that will do the damage. It won’t matter whether it comes down in Long Island Sound or in Times Square—it’s the impact with the atmosphere that will cause about twenty million deaths.

     No one said anything. The five men in the screen looked at him in blank-faced horror.
     "You know what happens when a jet plane goes over a city too low?" Stanley said. "A supersonic jet can break windows. What sort of sound wave do you think a five-hundred- metric-ton spaceship will cause at—seventy-two thousand miles an hour?
     "I’ll tell you. It would flatten every structure for miles around. If that ship hits Long Island Sound, New York City will be toppling in ruins before it ever arrives! Every town on Long Island is going to be pancaked. From Newark, New Jersey, to Hartford, Connecticut, that shock wave will knock over everything standing. This isn’t a matter of a few people in a ship dying; it's a matter of millions!”
     The civilian looked at General Hagopian.
     “He’s right,” said the general, in a strangled voice.
     "How much time do we have left?” the civilian demanded, white-faced.
     "Only a few minutes,” Stanley said coldly. He looked at his watch. "Hardly any time at all.”
     "Why didn’t you call us before this?”
     "I called as soon as I heard,” Stanley said. "It took time to get all you people together. It took time to compute what was going to happen.”
     In the background of his screen, he saw two of the civilians engaging in some rapid-fire exchange of conversation. "Can we evacuate?” the third civilian asked.
     "In five or six minutes? Don’t be silly.” Stanley seemed utterly cool now, in sharp contrast to the five who faced him. "We couldn’t have gotten all those people out of that area even if we’d started evacuating the moment the Queen had its accident— or half a day before, for that matter.”
     The civilian looked angry, but he said nothing.
     “What do you suggest, general?” said Hagopian.
     "There’s only one thing to do,” Stanley said levelly. "We’ll have to send up a rocket with an atomic warhead and blast that ship into gas before it hits.”
     There was a stunned silence. Stanley counted five before anyone spoke. This was the moment he had waited for—the moment when he had to give the brass the only answer to the problem of what to do with the oncoming Queen. The reaction was as expected.
     The civilian said: "Are you crazy? Blow up a hundred and eighty innocent people? There must be some other way.”
     "But there isn’t,” Stanley said flatly. "There never has been. There is only one thing to do.”
     "But we can’t permit that!” the civilian protested. "It’s murder!”
     "Murder? Is it murder to kill people who are already doomed? Is it murder to save the lives of twenty million people? Pardon me for being melodramatic, but I don’t like the idea any better than you do. It was difficult for me to convince myself that there was no other way.”
     "There must be another way,” said the civilian frantically. "Send up a rescue ship immediately! Hagopian, order him to send up a—”
     Stanley’s jaw muscles stood out. Without waiting for the civilian to finish speaking, he said, "Look here, you blockhead. Do you understand that it’s impossible to send up a rescue ship? Do you understand that I can’t pull miracles out of a hat? It’s as impossible to send up a rescue ship as it is to catch the Martian Queen with your bare hands.”
     "You can't talk to me that way, general!’’
     Stanley glanced at Hagopian. The military man was saying nothing, but there was the faint suggestion of a smile around his thin lips.
     "I’m simply trying to get you to understand,” said Stanley. "All of you. There is no other way out! None! Those people are going to die. D-I-E. It would be better if they died without taking a few million people with them. Is that clear?”

     Stanley waited for a reply, and, sure enough, it was forthcoming. One of the other civilians said, "Couldn’t we divert it from its course somehow?”
     "Not without destroying it,” Stanley said. "Which is exactly what I want to get permission to do.”
     "I’m afraid that’s impossible, general. The public would never sanction —”
     "The public be damned! It’s the public who is going to die! Die! Do you understand that? Twenty million people! Twenty million corpses to dig out from under ten thousand square miles of rubble!”
     "That’s ridiculous!” said the third civilian. They were doggedly trying to talk Stanley out of insisting on this thing, it seemed. "How could a shock wave do all that?”
     "How could it do it? It’s done it! Didn’t you ever hear of the Great Siberian Meteor that landed around 1908? It only came in at a speed of ten miles a second or so —half the Queen's—and it laid waste hundreds of square miles of forest. Trees fell like matchsticks. And this ship is going about twice as fast!”
     "There must be something else we can do,” said the first civilian stubbornly.
     "All right,” Stanley said. "Start making suggestions.”
     "Exactly. There is nothing else we can do,” he repeated. He glanced again at the clock. "Do I have your permission to send up an atomic warhead, then?”
     "No!” came the answer. The first civilian was doing all the talking now. "That’s out of the question. There must be another way.”
     "There isn’t,” Stanley said. "And wishing won’t make it so. You can't wish away the laws of the universe —you’ve got to obey them. And that’s exactly what the Martian Queen is doing! And that’s exactly what New York is going to do when that shock wave hits!”
     He paused and stared at them. ”1 ask you again: Do I have permission to send up that bomb?”
     "I hardly see how we can sanction it, general. We’ll have to find some other way.”
     Stanley looked at the clock and sighed.
     "It’s too late now anyway,” he said softly. "While we’ve been haggling, the Queen has been falling. It couldn't wait. Even if you ordered it, I couldn’t get a bomb up there now.”
     Two of the men looked fearfully out of the window toward the north. Stanley caught the gesture; he couldn’t see the window on his screen, but he knew what they were looking for. From Washington, such a display would be easily visible.
     "Oh, it won’t land,” said Stanley. His voice sounded old and tired. "There won’t be any crash. I sent up an XV-19 under robot control several minutes before you gentlemen got together. It was loaded with a thermo nuclear warhead. Captain Deering will—or I should say has—guided it in. The Martian Queen was vaporized over a minute ago. It was the only thing to do.”
     One of the men covered his face with his hands. Stanley wondered who he was.
     "I presume you know what this means,” asked General Hagopian quietly.
     "I know,” said Staney. "If I get out of it with a whole skin, I'll still lose everything I’ve ever worked for. It doesn’t matter. At the courtmartial, I can still know that I’ve saved the lives of millions of people.”
     General Hagopian nodded. "That will be a point in your favor. But there’s nothing else we can do; you can see that. You’ll have to roast.” Then Hagopian looked steadily at Stanley. "You’re a very brave man, general. It’s too bad that most people will never understand what you did—and why.”
     Stanley forced a smile. "The people who matter will understand, general. And they’re the only ones who count.”

From SOUND DECISION by Robert Silverberg and Randall Garrett (1956)

Establishing Spaceguard

Getting a Spaceguard system set up is going to be tricky. Quis custodiet ipsos custodes? and all that.

Before spaceguards with space ships are established as a branch of the military, any civilian attempts at asteroid re-direction will have to be accompanied by a division of army solders. From several nations. Every propulsion event will have to have the math checked by military astrogators. Of each nation. And the execution of the propulsion events will be closely monitored. At gun point. Of each nation.

Don't forget the army fire-teams tasked with aiming their weapons at each of the foreign army divisions, just in case they try pulling a fast one. Don't drop an incandescent light-bulb or otherwise make a noise sounding like a rife-shot. Otherwise when the firing stops everybody will be dead and the room will look like a colander.

It is probably a requirement to have several nations establish spaceguards with space ships, since a single nation with a monopoly on orbit guards is dangerous. Not just that the owning nation might issue covert orders to "accidentally" drop an asteroid on hostile nation Y. There is also the danger that a spaceguard ship might revolt, be infiltrated by terrorists, be composed of enemy sleeper agents, snap under the pressure and go insane, be part of a military coup conspiracy, or otherwise turn rogue and drop an unauthorized rock on some nation. Including the owning nation.

If there are spaceguard ships from other nations constantly watching your spaceguard suspiciously, it becomes much more difficult for a ship to go rogue. It is much safer to have several nations with spaceguards.

Perhaps it would make sense to have something like the Two-Man Rule used in nuclear launch protocol. Spaceguard ships of a given nation would go in pairs, watching each other. Or in triples, in case one ship becomes disabled. You see how the complexity quickly snowballs.

And you want to set things up to make impossible any dangerous situations such as are found in Dr. Strangelove and Fail-Safe.

However the Two-Man Rule was designed to prevent something from happening, not to ensure something happens. If Spaceguard ships Alfa and Bravo are near an asteroid, and Bravo turns rogue and tries to push the asteroid so it obliterates Terra, then according to the safeguard of the Two-Man Rule ship Alfa will shoot the ever-living snot out of ship Bravo. Everything is fine.

What is not so fine is if ships Alfa and Bravo are trying to save Terra by redirecting an asteroid aimed by Dr. Evil. Ship Alfa can start the redirection process, only to get the ever-living snot shot out of it by the subverted Ship Bravo. In this case the Two-Man Rule fails to ensure the desired result happens.

The spaceguard ships also might contain self-destruct devices, controlled by the owning government. Though you'd better be darn sure the enemy doesn't get its hands on the destruct codes. Or you will be really angry when your entire spaceguard fleet goes poof!

However, a spaceguard can still be used for nefarious purposes, such as making an excuse to annex the Asteroid miners.



  • 1. Requirements and Procedures.
    • 1.1. Tamper Control Program. The Two-Person Concept (TPC) is central to nuclear surety tamper control measures in the Air Force. It is designed to make sure that a lone individual cannot perform an incorrect act or unauthorized procedure on a nuclear weapon, nuclear weapon system, or certified critical component.
    • 1.2. Concept Enforcement. Each organization with a mission or function involving nuclear weapons, nuclear weapon systems, or certified critical components:
      • 1.2.1. Identifies no-lone zones (where at least two authorized persons must be present during any operation or task).
      • 1.2.2. Enforces the Two-Person Concept.
      • 1.2.3. Develops procedures to limit entry to authorized persons who meet the requirements of paragraph 1.3.
    • 1.3. Team Requirements. (Refer to paragraph 1.6.1 for criteria on foreign nationals.) A TwoPerson Concept team consists of at least two individuals who:
      • 1.3.1. Are certified under the Personnel Reliability Program (PRP), as specified in DoD 5210.42-R_AFMAN 10-3902, Nuclear Weapons Personnel Reliability Program.
      • 1.3.2. Know the nuclear surety requirements of the task they perform.
      • 1.3.3. Can promptly detect an incorrect act or unauthorized procedure.
      • 1.3.4. Have successfully completed nuclear surety training according to AFI 91-101, Air Force Nuclear Weapons Surety Program.
      • 1.3.5. Are designated to perform the required task.
    • 1.4. Two Person Concept Violations. Report a Two-Person Concept violation when a lone individual in a no-lone zone has the opportunity to tamper with or damage a nuclear weapon, nuclear weapon system, or certified critical component. Refer to AFMAN 91- 221, Weapons Safety Investigations and Reports, for reporting guidance.

After arriving at the LCF, a missile crew had their identification examined by the flight security controller and then began the authentication procedure with the on-duty missile crew. After they cleared security, they descended down the elevator to the LCC, also known as the "no-lone zone," because one could never enter the capsule alone. After arriving at the blast door a voice would shout "clear" from inside the capsule. The oncoming crew shouted back and the eight-ton door slowly swung open.

Once inside the capsule, the missile crew's shift began during a process called changeover, a formal procedure that allowed for the changing of crews in the LCC. The changeover included a ten-minute briefing on the weather report, call signs, a classified advisory on the day's war plan, and the placement of each crew member's padlock on the metal box that secured the launch keys. The changeover concluded with each departing crew member handing over three items to the deputy and commander— a three-by-five inch card encased in plastic and framed in metal with the day's top secret code to decipher commands from SAC; a key to be inserted into the console and turned in order to fire the missiles; and a .38-caliber revolver. The gun, worn in a holster, was for protection in the unlikely event of intruders. The missile combat crew was prohibited from taking off the holster while in the capsule.

After the capsule door closed, a new crew would check the maintenance logs and inspect support equipment. The duration of their shift was spent running practice drills or reviewing procedures to prepare for SAC's random Operational Readiness Inspections, an examination performed by an Inspector General to determine the effectiveness of the combat crews. The crew had very precise procedures for every task. If they ever received a launch command, both crew members would open the locked box that contained "cookies," or the authentication codes. Once the crew members agreed that the command was authentic they would insert the keys and turn them at the same time, launching a missile.

To launch a missile, an Emergency War Order (EWO) would have come over the SAC radio with a message that the crew had to authenticate. After they agreed that the message was authentic, they unlocked their padlock on the red metal box that contained two keys for launching the missiles. Each crew member would then buckle into their seats and the commander would count down. The deputy commander then flipped a row of "arming" switches for each of the missiles, making them readied for immediate launch. The commander opened the plastic cover over his launch control panel in front of him exposing the area for the launch key, and the deputy commander removed the plastic cover over the cooperative launch switch. Each crew member would insert their key and a "conference call" is ordered where the crew speaks via phone and headset to the squadron command post for readiness reports on other Minuteman capsules. The command post then issues a command to "launch on your count." On the commander's count, both crew members would have to turn the keys at the same moment. The two ignitions are situated far enough apart that one person alone could not reach both keys and single-handedly provide the go ahead to launch a missile. The Minuteman missile cannot be launched without a corroborating signal from another LCC, providing the second vote. Launch procedures were modified slightly in later years when a launch enable control group signal panel was added to the Deputy Commander's Control Console. An unlock code was required to be inserted into the "code inert thumbwheel switches" of the launch enable control panel to enable missiles for launch.


Spaceguard Equipment

Spaceguard spacecraft will probably have the following equipment:

Large telescopes and other tracking equipment
While there will be Spaceguard bases keeping a sharp lookout for unauthorized asteroid redirection, the fleet of ships on patrol in the solar system will provide an important part of the service's observational capacity.
Nuclear detonation detectors
Because the most quick and dirty brute force way to change an asteroid's path is with nukes.
Asteroid redirection gear
To undo the damage done by rogue asteroid movers, re-re-directing the asteroid into a safe orbit.
The rogue asteroid movers might fight to ensure their asteroid stays on its deadly track.

The Spaceguard spacecraft will carry their own high thrust equipment in order to re-direct errant asteroids. A nasty government might aim a large rock at an enemy nation then destroy the mass driver they used. The Spaceguard cannot count on the equipment being available to redirect the asteroid. The equipment might also become damaged in the battle to clear the asteroid of hostiles, especially if the bad guys use the mass driver as an impromptu kinetic energy weapon. The Spaceguard will be forced to neutralize the mass driver, which is never good for its warranty.

Asteroid Deflector, Nuclear

Scott Lowther figures that Orion drive style nuclear pulse units would be perfect tools for a spaceguard to redirect asteroids. Remember, they are not nuclear weapons that radiate their blast isotropically. They are nuclear shaped charges radiating about 85% of the explosive energy into a 22.5° cone.

Orion nuclear pulse units are more or less designed for the task (spacecraft pusher plate, asteroid, what's the difference?), they are powerful, small enough that any sized spaceguard ship can carry a large number of them (about 0.6 meters tall by 0.36 meters in diameter, mass 79 kg), and are certainly far more portable than lugging a full sized mass driver. If you position the charges far enough, the tungsten propellant will spread its impact evenly over the asteroid's entire hemisphere. This helps ensure that the asteroid is just nudged off course, not shattered into a deadly charge of cosmic buckshot still aimed at Terra.

The standard nuclear charge used in the USAF Orion report had a yield of one kiloton and would hit the asteroid with about 2.01 megaNewton-seconds of impulse. The Chelyabinsk meteor had a mass of about 10,000 metric tons. One USAF pulse unit would change its velocity by 0.2 meters per seconds. Doesn't sound like much but in the real world it's pretty good. So a single USAF charge could have made the Chelyabinsk meteor miss Terra by 100 kilometers if it was placed to detonate about six days before the meteor was scheduled to strike Terra. Or ten charges could make it miss by 100 kilometers if there was only 14 hours lead time prior to Terra impact.

(ed note: Isaac Kuo is of the opinion that standard Orion pulse units are sub-optimal for asteroid deflection.)

Given the extreme expense of the sort of nuclear bombs required for an Orion style propulsion system, and the stupendous cost of developing it, I don't think it's a good idea to develop it (there are numerous practical problems with using it, even if there were a budget to perform a mission with it).

In contrast, off the shelf nuclear bombs suitable for asteroid deflection have already been developed. The main expense is the weapons grade fission primary (which Orion style drives need oodles of), but the power of a nuke can be upscaled using cheap lithium deuteride stages — and using cheap waste U238 for the casing/tamper/etc. This results in a powerful nuclear bomb which spits out mostly neutrons — pretty useless for an Orion style drive, but ideal for asteroid deflection. These neutrons will penetrate into the asteroid and cause a nice layer of the asteroid to vaporize — producing thrust in an energy efficient (but mass inefficient) way.

This is the opposite of what you want for an Orion style drive. You do NOT want to vaporize the pusher plate of an Orion style drive, and if you're going to do something so mass inefficient you might as well use a low performance chemical rocket propulsion system instead.

Basically, the parameters of what's desirable for asteroid deflection and what's desirable (or even sensible) for an Orion style drive are too radically different. For asteroid deflection, it's actually good to have a specific impulse in the low triple digits (i.e., on par with chemical rocket Isp). This minimizes the energy required, and this in turn, reduces the mass of the nukes needed to deflect the asteroid. So what if you have to vaporize a significant fraction of the asteroid to do the mission?

And an Orion style drive does not play well with the fast neutrons of a lithium deuteride bomb. Fast neutrons penetrate a pusher plate...even if you downscale the nuke enough so it won't outright vaporize the pusher plate, the neutrons will cause damage. Lithium deuteride is good because it is much cheaper than fission bomb material and it gives more bang for a given amount of mass as well. The nice thing about upscaled fusion bombs is that the size/mass of the primary remains fixed (a fixed cost), while the additional lithium deuteride is very very cheap in comparison. But you know what you get if you try and use a few humongous nukes instead of thousands of little nukes to push an Orion style rocket ship? You get a blown up rocket ship.

The use of a 238U casing/tamper/etc doesn't really mix well with an Orion style drive either. The neutrons from 238U aren't so fast, but there are oodles of them. This is great for asteroid deflection because the extra oomph from 238U is extra energy in neutrons that are still nicely penetrative.

Isaac Kuo in a comment to a Google+ thread (2015)

Employees of the Department of Celestial Mechanics and Astrometry NII PMM and colleagues from St. Petersburg State University, Keldysh Research Center, and Research Institute Sirius are developing measures to protect the Earth from potentially dangerous celestial bodies. With the help of supercomputer SKIF Cyberia, the scientists simulated the nuclear explosion of an asteroid 200 meters in diameter in such a way that its irradiated fragments do not fall to the Earth.

- The way we propose to eliminate the threat from space is reasonable to use in case of the impossibility of the soft disposal of an object from a collision in orbit and for the elimination of an object that is constantly returning to Earth, - says Tatiana Galushina, an employee of the Department of Celestial Mechanics and Astrometry - Previously, as a preventive measure, it was proposed to abolish the asteroid on its approach to our planet, but this could lead to catastrophic consequences - a fall to Earth of the majority of the highly radioactive fragments.

TSU scientists with colleagues from other research centres have offered another solution to the problem. It is known that the majority of dangerous objects pass close to Earth several times  before the collision. Therefore, there is a possibility to blow up the asteroid at the time when it is farther from the planet. This measure will be much more effective and safer.

For computer modeling as a potential target was taken a celestial body with a diameter of 200 meters, similar to the asteroid Apophis, which in 2029 will approach Earth at a distance of 38,000 kilometers. Calculations have shown that for the destruction of the object there must be the impact of a nuclear device with energy of one megaton of TNT equivalent. In this case, part of the asteroid turns into gas and liquid droplets, and some will break into pieces no larger than 10 meters. This is the maximum in terms of safety for the Earth.

- Because the rocket catches behind the asteroid, almost all the pieces after the destruction will fly forward, - says Tatiana Galushina. - In this case the orbit of the fragments will be significantly different from the asteroid's orbit. For 10 years after the explosion an insignificant number of fragments will fall to Earth. Their radioactivity during this time will be reduced considerably, and after a few years they will not pose a danger. It is worth adding that nuclear explosions in space are prohibited by international treaty, but in the case of a real threat to humanity maybe there will be an exception to this rule.

Specialists from different areas who are experts in celestial mechanics and ballistics worked on the project. The scientists note that the theoretical calculations are only the beginning of the work, without which the practical implementation on the preventive measures protecting the Earth is impossible.


A research collaboration between Lawrence Livermore National Laboratory (LLNL) and the Air Force Institute of Technology (AFIT) investigates how the neutron energy output from a nuclear device detonation can affect the deflection of an asteroid.

Scientists compared the resulting asteroid deflection from two different neutron energy sources, representative of fission and fusion neutrons, allowing for side-by-side comparisons. The goal was to understand which neutron energies released from a nuclear explosion are better for deflecting an asteroid and why, potentially paving the way for optimized deflection performance.

The work is featured in Acta Astronautica and was led by Lansing Horan IV, as part of a collaboration with LLNL’s Planetary Defense and Weapon Output groups during his nuclear engineering master’s program at AFIT. Co-authors from LLNL include Megan Bruck Syal and Joseph Wasem from LLNL's Weapons and Complex Integration Principal Directorate, and the co-authors from AFIT include Darren Holland and Maj. James Bevins.

Horan said the research team focused on the neutron radiation from a nuclear detonation since neutrons can be more penetrative than X-rays.

“This means that a neutron yield can potentially heat greater amounts of asteroid surface material, and therefore be more effective for deflecting asteroids than an X-ray yield,” he said.

Neutrons of different energies can interact with the same material through different interaction mechanisms. By changing the distribution and intensity of the deposited energy, the resulting asteroid deflection also can be affected.

The research shows that the energy deposition profiles — which map the spatial locations at and beneath the asteroid’s curved surface, where energy is deposited in varying distributions — can be quite different between the two neutron energies that were compared in this work. When the deposited energy is distributed differently in the asteroid, this means that the melted/vaporized blow-off debris can change in amount and speed, which is what ultimately determines the asteroid’s resulting velocity change.

Defeating an asteroid

Horan said there are two basic options in defeating an asteroid: disruption or deflection.

Disruption is the approach of imparting so much energy to the asteroid that it is robustly shattered into many fragments moving at extreme speeds.

“Past work found that more than 99.5 percent of the original asteroid’s mass would miss the Earth,” he said. “This disruption path would likely be considered if the warning time before an asteroid impact is short and/or the asteroid is relatively small.”

Deflection is the gentler approach, which involves imparting a smaller amount of energy to the asteroid, keeping the object intact and pushing it onto a slightly different orbit with a slightly changed speed.

“Over time, with many years prior to impact, even a miniscule velocity change could add up to an Earth-missing distance,” Horan said. “Deflection might generally be preferred as the safer and more ‘elegant’ option, if we have sufficient warning time to enact this sort of response. This is why our work focused on deflection.”

Connecting energy deposition to asteroid response

The work was conducted in two primary phases that included neutron energy deposition and asteroid deflective response.

For the energy deposition phase, Los Alamos National Laboratory's Monte Carlo N-Particle (MCNP) radiation-transport code was used to simulate all of the different case studies that were compared in this research. MCNP simulated a standoff detonation of neutrons that radiated toward a 300 m SiO2 (silicon oxide) spherical asteroid. The asteroid was divided by hundreds of concentric spheres and encapsulated cones to form hundreds of thousands of cells, and energy deposition was tallied and tracked for each individual cell in order to generate the energy deposition profiles or spatial distributions of energy throughout the asteroid.

For the asteroid deflection phase, LLNL’s 2D and 3D Arbitrary Lagrangian-Eulerian (ALE3D) hydrodynamics code was used to simulate the asteroid material’s response to the considered energy depositions. The MCNP-generated energy deposition profiles were imported and mapped into the ALE3D asteroid in order to initialize the simulations. The resulting deflection velocity change was obtained for various configurations of neutron yields and neutron energies, allowing for the effect of the neutron energy on the resulting deflection to be quantified.

One small step for deflection

Horan said the work is one small step forward for nuclear deflection simulations.

“One ultimate goal would be to determine the optimal neutron energy spectrum, the spread of neutron energy outputs that deposit their energies in the most ideal way to maximize the resulting velocity change or deflection,” he said. “This paper reveals that the specific neutron energy output can impact the asteroid deflection performance, and why this occurs, serving as a stepping stone toward the larger goal.”

Horan said the research showed that precision and accuracy in the energy deposition data is important. “If the energy deposition input is incorrect, we should not have much confidence in the asteroid deflection output,” he said. “We now know that the energy deposition profile is most important for large yields that would be used to deflect large asteroids.”

He said if there were to be a plan to mitigate a large incoming asteroid, the energy deposition spatial profile should be accounted for to correctly model the expected asteroid velocity change.

“On the other hand, the energy coupling efficiency is always important to consider, even for low yields against small asteroids,” he said. “We found that the energy deposition magnitude is the factor that most strongly predicts the overall asteroid deflection, influencing the final velocity change more than the spatial distribution does.”

For planning an asteroid mitigation mission, it will be necessary to account for these energy parameters to have correct simulations and expectations.

“It is important that we further research and understand all asteroid mitigation technologies in order to maximize the tools in our toolkit,” Horan said. “In certain scenarios, using a nuclear device to deflect an asteroid would come with several advantages over non-nuclear alternatives. In fact, if the warning time is short and/or the incident asteroid is large, a nuclear explosive might be our only practical option for deflection and/or disruption.”

Asteroid Deflector, Antimatter



An earth protection system against asteroids and meteorites in colliding orbit is proposed. The system consists of detection and deorbiting systems. The analyses are given for the resolution of microwave optics, the detectability of radar, the orbital plan of intercepting operation, and the antimatter mass required for total or partially blasting the asteroid. Antimatter of 1 kg is required for deorbiting asteroid of 200 m in diameter. An experimental simulation of antimatter cooling and storage is planned. The facility under construction is introduced.


     The space activities of mankind have been supported by

     1) curiosity in sense to find new laws of universe and in exploration to find new world.

and will be so in future. Another motivation of space activities especially in future is

     2) desire to preserve the human race, i.e. instructive move for survival.

The second motivation may take the form of Solar Power Satellite (SPS) and human resource exploitation, i.e. helium 3. These are counter action against the energy crisis coming in future. The energy crisis is related to the expansion of human activities. On the other hand, there is another type of crisis, the natural disaster caused by asteroid collision with the earth.

     Asteroids approaching to the earth have so high relative velocities about 30 km/s that the kinetic energy is extremely large even if it is much smaller than the earth. Asteroids collision with the earth result in not only the craters formation and tidal waves but also the earth environment modification. The Hiroshima atomic bomb has an energy of 1015 J, which corresponds to the estimated kinetic energy of a meteorite, 10 m in diameter and 5 in specific gravity. Celestial body in 10 m class crashes on the earth once every several hundreds years. It is reported that a collision with a meteorite in the Cretaceous period changed the climate and exterminated the dinosaur in the mass. The collision correspond3 to 5 billion Hiroshima bombs. The asteroid collision equivalent to the dinosaur extinction happens once per 100 million years.

Asteroids very frequently near-miss the earth as shown in Fig.1. Figure 1 is not a complete list since the asteroids in Fig.1 were accidentally observed by voluntary observers. The 1989 FC passing by the earth on March 22 in 1989, had several times as large kinetic energy as the asteroid which formed the Arizona's famous 1.2km meteor crater.

     Antimatter annihilation propulsion for interstellar and deep space missions has been recently studied because of high energy density of antimatter-matter reactions. Most of the studies emphasize the mission analyses and the conceptual designs of antimatter engines. On the other hand, we have been studying the storage of the antimatter and considering the application of the earth protection system against asteroid collisions.

     The asteroids uf 10-100 m size, which had impinged in the ocean and caused global weather impact, may not be recorded in the history books.

     The earth protection system presented here not only actively detects the celestial bodies approaching to the earth but also modifies their orbit. The objectives of this paper are:

     1) to estimate distance to detect asteroids from the earth and remaining time before collision,

     2) to estimate requirements for radar system characteristics using Very Long Base Line Interfercmetry (VLBI),

     3) to estimate the amount of antihydrogen for the orbital modification of meteorites,

     4) to examine antimatter storage,

     5) to design the antimatter factory and base.


     In order to make the analysis simple, three dimensional effects such as the inclination of the asteroid orbit are ignored. Meteorites are either comets or minor planets. Based on orbital data of comets, the eccentricities are found around 0.8 and the distance of perihelion ranges from 0.13 to 0.98 a.u..

Figure 2 shows the relation between the remaining time and the distance. The asteroid is assumed to move frem the aphelion toward the orbit of the earth in the calculation. While the orbital radius distributes from 2 to 3 a.u. in the case of meteorites which are categorized as minor planets. It is concluded from these results that the distance to have to detect the asteroid is 1 a.u. and the remaining time before encounter is from 2 to 3 months.


     The radar system is required to detect and track an object approaching to the earth as soon as possible. Suppose the asteroid of 100 m in diameter is detected at 1 a.u. distance from the earth. A great number of celestial bodies are observed by the photographic method with large telescopes. Asteroids approaching to the earth are discovered and tracked by the radar. The precision for the tracking radar requires 0.1 nrad in angular resolution. Such a resolution can be achieved by VLBI in radio astronomy such as VSOP (VLBI Space Observatory Program) in Institute of Space and Astronautical Science (ISAS). For the purpose of determination of transmission power of microwave, wave length, diameter of antennas and baseline distance, it is assumed:

     1: Antenna for microwave transmission are the same size as receptive one.

     2: Receptive sensitivity is 10-20W.

     3: Microwave is scattered at the asteroid's surface uniformly and isotropically.

     4: Reflectivity of asteroids is 0.1.

The first assumption is made only for convenience. The second precision corresponds to an observation of a radio galaxy with 1 mJy (1Jy=10-26Wm-2Hz-1) by a radio telescope which is 100 m in diameter and 100 kHz in band width. The third assumption is very natural since the surface unevenness is larger than the wave length. The reflectivity of Apollo objects is assumed to be 0.1.

     Now we derive the relation between the transmitted and the received power. Microwave beam diverges with transmitting distance. The theoretical minimum for beam collimation is given by

A: cross sectional area of microwave beam
L: distance between asteroid and the earth
d: diameter of transmit and receptive antenna
λ: wavelength of microwave.

The power received by the receptive antenna is given by the equation

Pa : received microwave power
Pt : transmitted microwave power
δΩ : solid angle of receptive antenna measured from asteroid
D : asteroid diameter
The angular resolution of VLBI can be estimated to be the order of λ/L. The power required for each satellite is about 10 kW if the millimeter wave is transmitted at 10 Hz repetition with the pulse width of 10 μs. The required characteristics of the radar system are summarized in Table 1.
Table 1: Specifications of the Radar System
diameter of asteroid100 m
diameter of antennas25 m
received power10-20W
wave length0.1 mm
peak power of microwave100 MW
number of transmission satellites10
baseline distance1000 km

As exhibited in Table 1, these satellites are only 2.5 times larger than that of the VSOP in size. The surface accuracy of the receptive antenna, however, will be required at least 2 order of magnitude higher than that in VSOP since the parabolic surface of the VSOP is controlled to maintain within the small displacement of 0.1mm. It is indicated that additional difficulties are found by the VLBI of millimeter range at present.


     For small asteroids, the interceptors loaded with the antihydrogen can destroy them completely. If the asteroid is too large to be entirely exploded, it is necessary to penetrate into the celestial body and blast off the surface materials effectively. It is estimated in the case of orbital change using explosion that the energy utilization efficiency is less than 1% i.e. the ratio of the exploded mass to the remaining mass of the asteroid.

     The antimatter-matter annihilation generates shock wave and produces high energy plasma at the center of the explosion. If the plasma dissipates its energy to surrounding materials efficiently, lava with high energy will be blasted off. The reaction against the astereid produces the thrust. The energy E generated by the annihilation is related:

ρ : asteroid density
r : diameter of lava region ( depth of penetration )
M : asteroid mass
ΔVmelt : effective velocity corresponding to melting energy
U : mean velocity of lava

The first term of the right hand side of Eq.(3) represents the internal energy and the second one does the kinetic energy of the lava. It is assumed that a half of the lava blasts and contributes to the orbital modification, and the rest half merely heats up surroundings. The velocity change V and the efficiency η are calculated:

The radius r is a control parameter of the explosion (or thrust generation). Choosing r so as to maximize the efficiency:

are obtained as the optimum velocity change and penetrating depth. For example, the optimum depth is estimated to be 240 m from Eq.(7) for the antihydrogen of 1 kg.

     Figure 3 shows the relation between the mass of the antihydrogen and the delta-V calculated from Eq.(4). A value of 1m/s is the minimum delta-V required for the orbital change if the orbit is modified at 1.3 a.u. distance from the sun. Generally, the minimum delta-V is a function of the orbital elements, the direction of the thrust and the distance from the earth.

The closest distance between the earth and the asteroid is plotted in Fig.4 with thrusting directions as parameters. The optimum direction is either parallel or anti-parallel to the orbiting direction of the asteroid. The delta-V at ϑ=π/3 is ten times as high as that at ϑ=0 for given distance.

Figure 5 shows the closest distance as a function of delta-V on deorbiting position as parameter. The delta-V required for 1.55×108km is ten times as large as that for 2×108km. As the farther distance the orbit is modified, the smaller the delta-V is required. This means the importance of the early detection and the orbital modification as soon as possible.


     At present, antiprotons are generated by the method of a collision between a heavy metal target and a proton beam which is accelerated up to several tens of GeV or more. Reference 8 reports that 1011 antiprotons (~pg) are obtained per hour in Fermilab. The productive amount of the antiprotons has been increased at the rate of 10 times per 3.5 years ever since the discovery by Segre and Chamberlan so that the antiproton will be available industrially in 2020's if it monotonically increases (sadly, this did not happen). It is necessary that the antimatter is stored as solid antihydrogen at cryogenic temperature since the antimatter required for the orbital modification amounts to the order of kg or more as seen in Fig.3.

     The storage processes are shown in Fig.6. At first, the produced antiparticles are cooled by stochastic and electron coolings because antiprotons are tremendously hot Just after they are generated by an accelerator. They are decelerated as slow as several keV and are turned into the antihydrogen by three body recombination with cold positrons. The unrecombined particles are cycled in the antiproton and positron rings being collimated with accelerator and electrostatic lens. The resultant antihydrogen beam is decelerated and trapped by means of laser cooling. A vacuum ultraviolet CW laser for the hydrogen cooling have not been accomplished yet, but will be put to practical use in near future with stable multi-ionized ion sources recently accomplished. Solid antihydrogen is produced from the trapped antihydrogen, and is stored electrostatically.

     Experimental demonstration is in progress with respect to the recombination and the deceleration of the antihydrogen. The antihydrogen is simulated by ordinary matter argon in the experiment, since antiparticle can be regarded as particle with opposite charge without annihilation. Except for the differences in the mass and the energy level for the laser cooling, the argon in a metastable state has the advantage of being incorporated with laser diode, which has energy level related to near infrared range. The photograph of the experimental apparatus is shown in Fig.7. It consists of a plasma source which simulates a low energy antiproton beam, a recombination chamber, a cooling and trapping chamber.


     Necessary conditions for establishing the antimatter factory and the interceptor base comprises;

     1: Sufficient solar power can be easily obtained,

     2: Energy to launch the interceptor is small,

     3: The earth's safety is assured at an accident.

The construction of the factory farther than the Mars orbit from the sun is not beneficial since the SPS (Solar Power Satellite) collects solar energy to produce antimatter. Lagrange points of L4 and L5 between the sun and the earth have the advantage of the minimum launching energy since they are the points of the gravitational equilibrium. It is also convenient from following stand-points to construct the plant on the back side of the SPS. First, the plant is cooled down as cryogenically as the space back ground temperature of 3 K because of isolation from the solar energy flux. Second, the high vacuum environment keeps the loss rate of the stored antimatter low because of low background density, a few particles per cm3. Even if the disaster by the annihilation occurs in the plant, the irradiation from the antimatter factory remains as low as several times of natural level at the earth with 150 million km (1 a.u.) distance between the earth and the plant.

     Next we estimate the antimatter fuel to be changed in the interceptor. Suppose the interceptor encounters the asteroid at 200 million km from the sun in 30 days after launch. The necessary delta-V is about 30 km/s when the interceptor is launched in the same dlrection as the earth evolution, and about 90 km/s in the opposite direction. As for the latter mission, it is impossible for chemical rockets because of large payload mass ratio of 109. However, antimatter engine enables such a mission since the specific impulse can be chosen just like electric propulsion and the thrust density is as high as that of the chemical rocket. Forward indicates that the payload mass ratio of the antimatter rocket do not exceed 5.

     The mass of the vehicle, m is assumed as 1 ton including an apparatus for the antimatter storage. Energy utilization efficiency ε by the antimatter-matter reactions is assumed as 0.32. The necessary antimatter is given by

mv : mass of vehicle included an apparatus for antimatter storage
ma : mass of antimatter propellant
ε : energy utilization efficiency by annihilation
ΔV : mission delta-V
c : speed of light

Substituting ΔV=90km/s into Eq.(8), the required amount of the antimatter is 0.1g at most, which is negligible compared with that for the orbital modification of the asteroid. The mass of the reaction fluid is 4 ton. Consequently, the launching from the antimatter base located on the Lagrange points is possible. The earth protection system is schematically shown in Fig. 8.


     First, necessity of the earth protection system against the meteorite collisions is investigated. The designed system consists of the VLBI radar tracking system, the antimatter plant and the interceptor to modify asteroid orbits. The radar tracking an asteroid by means of VLBI is feasible considering the state of arts of required technology. Some issues of millimeter wave remains open. An experimental simulation for the antimatter storage is introduced. It is desirable to construct the antimatter plant and the interceptor base combining the SPS at the Lagrange point. Destruction or orbital change of asteroids is concluded to be impossible without use of the annihilation energy.

Asteroid Deflector, Mass Driver

If Spaceguard ships carrying Orion nuclear pulse units does not appeal to you, then perhaps the Spaceguard ships will have mass drivers as propulsion. And a large thrust bracing on the nose. After the resistance has been neutralized (i.e., all the evil asteroid movers have been blasted or are in custody) the Spaceguard ships will land on the asteroid, ship noses pressed into the aseroid's surface and the ship tails pointed skyward, deploy scoop conveyor belts to grab reaction mass, and start running their mass drivers at full bore.

Legitimate and illegitimate asteroid movers will probably have to make do with mass drivers instead of Orion pulse units. Most military forces are quite unreasonable about allowing nuclear devices into civilian hands. Evil asteroid movers might illegally use Orion units, but they will have to work quick. Multiple nuclear detonations will be visible all over the solar system and will quickly draw unwanted attention.

SpaceWorks Engineering did a study for NASA about deflecting killer asteroids on collision course with Terra. The concept they came up with is Modular Asteroid Deflection Mission Ejector Node (MADMEN) robots. They are unmanned, independently controlled, nuclear powered, and equipped with a powerful mass driver. The idea is to make a solution that is "scaleable". If the asteroid is larger, then send more MADMEN modules. Plus a few extras in case some of them suffer malfunctions.

A transfer vehicle delivers a MADMEN to the impactor asteroid. The MADMEN lands at the correct spot, the landing gear digs in to anchor the MADMEN, the heat radiator and mass driver unfurls, the reactor powers up, a drill head extend into the body of the asteroid to gobble rocks for mass driverpropellant, and the mass driver proceeds to lob the rocks at a rate of one per minute. If the asteroid is rapidly rotating, the MADMEN is intelligent enough to only fire a rock when the rotation brings the mass driver to point in the desired direction. The thrust of the mass drivers gradually alters the trajectory of the asteroid into a safe direction.

These would be useful to both Spaceguard and to evil asteroid movers. Spaceguard can station caches of MADMEN in strategic locations, without having to worry about life support for Guard crews (MADMEN are unmanned, remember?). Evil movers will not have to worry about Spaceguard capturing evil crews, who might be coerced into revealing which evil nation is responsible for the evil plot. MADMEN may also be easier for evil asteroid movers to secretly emplace on a lonely asteroid, but the onboard reactor and heat radiators will rapidly give away their positions once powered up.

Baseline MADMEN lander parameters
Ejection Velocity187 m/s
Ejecta mass per shot2 kg
Mass driver length10 m
Shot frequency1 per minute
Total surface time of proces60 days
Total power required42.2 kW
Length13.97 m
Height2.54 m
Width2.54 m
Dry Mass1,503 kg
Gross Mass1,621 kg
Baseline mission parameters
Delta-V imparted to Killer Asteroid0.2 m/s
Killer Asteroid Mass2.7 × 109 kg
Killer Asteroid Diameter130 m
Delta-V to get to Killer Asteroid5,423 m/s
Dry Mass (with MADMEN payload)2,207 kg
Gross Mass (with MADMEN payload)8,816 kg

Gravity Tractor


A gravity tractor is a theoretical spacecraft that would deflect another object in space, typically a potentially hazardous asteroid that might impact Earth, without physically contacting it, using only its gravitational field to transmit the required impulse. The gravitational force of a nearby space vehicle, though small, is able to alter the path of a much larger asteroid if the vehicle spends enough time close to it; all that is required is that the vehicle thrust in a consistent direction relative to the asteroid's path, and that neither the vehicle nor its expelled reaction mass come in direct contact with the asteroid. The tractor spacecraft could either hover near the object being deflected, or orbit it, directing its exhaust perpendicular to the plane of the orbit. The concept has two key advantages: namely that essentially nothing needs to be known about the mechanical composition and structure of the asteroid in advance; and that the relatively small amounts of force used enable extremely precise manipulation and determination of the asteroid's orbit around the sun. Whereas other methods of deflection would require the determination of the asteroid's exact center of mass, and considerable effort might be necessary to halt its spin or rotation, by using the tractor method these considerations are irrelevant.


A number of considerations arise concerning means for avoiding a devastating collision with an asteroidal object, should one be discovered on a trajectory that were determined to lead to Earth impact at some future date. One of the main challenges is how to transmit the impulse required (possibly quite large), to an asteroid of unknown mass, composition, and mechanical strength, without shattering it into fragments, some of which might be themselves dangerous to Earth if left in a collision orbit. The gravity tractor solves this problem by gently accelerating the object as a whole over an extended period of time, using the spacecraft's own mass and associated gravitational field to effect the necessary deflecting force. Because of the universality of gravitation, affecting as it does all mass alike, the asteroid would be accelerated almost uniformly as a whole, with only tidal forces (which should be extremely small) causing any stresses to its internal structure.

A further advantage is that a transponder on the spacecraft, by continuously monitoring the position and velocity of the tractor/asteroid system, could enable the post-deflection trajectory of the asteroid to be accurately known, ensuring its final placement into a safe orbit.


Limitations of the tractor concept include the exhaust configuration. With the most efficient hovering design (that is, pointing the exhaust directly at the target object for maximum force per unit of fuel), the expelled reaction mass hits the target head-on, imparting a force in exactly the opposite direction to the gravitational pull of the tractor. It would therefore be necessary to use the orbiting-tractor scheme described below, or else design the hovering tractor so that its exhaust is directed at a slight angle away from the object, while still pointing "down" enough to keep a steady hover. This requires greater thrust and correspondingly increased fuel consumption for each metre per second change in the target's velocity.

Issues of the effect of ion propulsion thrust on the dust of asteroids have been raised, suggesting that alternative means to control the station keeping position of the gravity tractor may need to be considered. In this respect, solar sails have been suggested.

According to Rusty Schweickart, the gravitational tractor method is also controversial because during the process of changing an asteroid's trajectory the point on Earth where it could most likely hit would be slowly shifted across different countries. It means that the threat for the entire planet would be minimized at the cost of some specific states' security. In Schweickart's opinion, choosing the way the asteroid should be "dragged" would be a tough diplomatic decision.


To get a feel for the magnitude of these issues, let us suppose that a NEO of size around 100 m, and mass of one million metric tons, threatened to impact Earth. Suppose also that

  • a velocity correction of 1 centimetre per second would be adequate to place it in a safe and stable orbit, missing Earth
  • that the correction needed to be applied within a period of 10 years.

With these parameters, the required impulse would be: V × M  = 0.01 m/s × 109 kg = 107 N-s, so that the average tractor force on the asteroid for 10 years (which is 3.156×108 seconds), would need to be about 0.032 newtons. An ion-electric spacecraft with a specific impulse of 10,000 N-s per kg, corresponding to an ion beam velocity of 10 kilometres per second (about 20 times that obtained with the best chemical rockets), would require 1,000 kg of reaction mass (xenon is currently favored) to provide the impulse. The kinetic power of the ion beam would then be approximately 158 watts; the input electric power to the power converter and ion drive would of course be substantially higher. The spacecraft would need to have enough mass and remain sufficiently close to the asteroid that the component of the average gravitational force on the asteroid in the desired direction would equal or exceed the required 0.032 newtons. Assuming the spacecraft is hovering over the asteroid at a distance of 200 m to its centre of mass, that would require it to have a mass of about 20 metric tonnes, because due to the gravitational force we have

Considering possible hovering positions or orbits of the tractor around the asteroid, note that if two objects are gravitationally bound in a mutual orbit, then if one receives an arbitrary impulse which is less than that needed to free it from orbit around the other, because of the gravitational forces between them, the impulse will alter the momentum of both, together regarded as a composite system. That is, so long as the tractor remains in a bound orbit, any propulsive force applied to it will be effectively transferred to the asteroid it orbits. This permits a wide variety of orbits or hovering strategies for the tractor. One obvious possibility is for the spacecraft to orbit the NEO with the normal to the orbit in the direction of the desired force. The ion beam would then be directed in the opposite direction, also perpendicular to the orbit plane. This would result in the plane of the orbit being shifted somewhat away from the center of the asteroid, "towing" it, while the orbital velocity, normal to the thrust, remains constant. The orbital period would be a few hours, essentially independent of size, but weakly dependent on the density of the target body.

From the Wikipedia entry for GRAVITY TRACTOR


     Given sufficient warning time, Earth-impacting asteroids and comets can be deflected with a variety of different “slow push/pull” techniques. The gravity tractor is one technique that uses the gravitational attraction of a rendezvous spacecraft to the impactor and a low-thrust, high-efficiency propulsion system to provide a gradual velocity change and alter its trajectory. An innovation to this technique, known as the Enhanced Gravity Tractor (EGT), uses mass collected in-situ to augment the mass of the spacecraft, thereby greatly increasing the gravitational force between the objects. The collected material can be a single boulder, multiple boulders, regolith or a combination of different sources. The collected mass would likely range from tens to hundreds of metric tons depending on the size of the impactor and warning time available. Depending on the propulsion system’s capability and the mass collected, the EGT approach can reduce the deflection times by a factor of 10 to 50 or more, thus reducing the deflection times of several decades to years or less and overcoming the main criticism of the traditional gravity tractor approach. Additionally, multiple spacecraft can orbit the target in formation to provide the necessary velocity change and further reduce the time needed by the EGT technique to divert hazardous asteroids and comets. The robotic segment of NASA’s Asteroid Redirect Mission (ARM) will collect a multi-ton boulder from the surface of a large Near-Earth Asteroid (NEA) and will provide the first ever demonstration of the EGT technique and validate one method of collecting in-situ mass on an asteroid of hazardous size.


     A variety of techniques have been proposed to deflect asteroids and comets that could impact the Earth and cause destruction and loss of life. Efforts to deflect these hazardous Near-Earth Objects (NEOs) significantly benefit from early detection and precise orbit characterization. Warning times on the order of a decade or more significantly reduce the impulse, or velocity change (ΔV), needed to deflect an impacting NEO. Accurate knowledge of the object’s orbit is needed to confirm that the object will indeed impact the Earth, which is possible with a sufficient number of accurate astrometric observations along with the possible addition of precise radar measurements or the presence of an in-situ spacecraft. As shown in Figure 1, the application of approximately one cm/s (0.022 mph) of ΔV a decade before impact is typically required to allow for a one Earth radius deflection. This would be the minimum impulse required to just avoid a worst case impact that hits the Earth “dead center.” Additional ΔV would be required for margin against the orbit uncertainty or the NEO’s orbit would need to be more of a grazing impact to assure that the object misses the Earth. This ΔV increases by approximately an order of magnitude within a year of impact, and surpasses a meter per second in the last months before impact.

Planetary defense techniques that can provide large, rapid impulses, such as kinetic impactors and nuclear detonations, require the least amount of warning time, but their effectiveness is dependent on the NEO properties, which are likely uncertain and vary substantially between objects. Additionally, the application of a large, concentrated force has the potential to fragment the NEO due to the unknown structure and mechanical properties of the target. These fragments could still be dangerous if they remain on an impacting trajectory with Earth. Techniques that can provide small, gentle impulses are much less likely to cause fragmentation, but typically require much longer interaction times (months to many years) to provide the necessary ΔV to deflect the impacting object. These “slow push/pull” techniques typically work by enhancing natural effects (e.g., albedo/thermal response modification via the Yarkovsky effect), by the ablation/expulsion of surface material, or by applying a contact or gravitational force. They are also effective against NEOs that are binary or even ternary systems. One consideration for these gradual deflection techniques is that when an impact with the Earth is confirmed, the exact impact point is still uncertain. This path of possible impact points, known as the “risk corridor,” is altered during a deflection effort with the impact point moving across the Earth’s surface as the impactor’s trajectory is slowly changed (see Figure 2 for an example). Choosing how the deflection is accomplished has significant geopolitical considerations and will likely require the cooperation of multiple nations. Finally, definitive knowledge that an impact will actually occur is often difficult to determine from ground-based measurements and the probability of impact will likely not be a certainty before a deflection mission is undertaken.

The gravity tractor is a planetary defense technique that uses the gravitational attraction between a rendezvous spacecraft and the NEO to gradually alter the trajectory of an impactor. With this approach, the spacecraft maintains separation from the NEO by using its thrusters to oppose the small gravitational attraction between the two bodies without pluming the NEO, which reduces the technique’s effectiveness. The gravity tractor requires the use of a low-thrust, high-efficiency propulsion system, such as Solar Electric Propulsion (SEP), to balance the gravitational force while minimizing the propellant required for the deflection. With this technique, the NEO is accelerated in a very uniform manner with only extremely small tidal forces causing any internal structural stresses. One of the shortcomings of the traditional gravity tractor approach is that the applied force is exceedingly small and depends on the mass of the spacecraft. This results in many years or decades of operation to alter the impactor’s trajectory and a decade or more of warning time.


The National Aeronautics and Space Administration (NASA) is currently developing a mission concept known as the Asteroid Redirect Mission (ARM), which includes the goal of robotically returning a multi-ton boulder (typically 2-4 meters in size) from a large Near-Earth Asteroid (NEA), 100 meters or greater in size, to cislunar space using an advanced 50 kW-class Solar Electric Propulsion (SEP) spacecraft designated the Asteroid Redirect Vehicle (ARV). After the ARV returns to a lunar distant retrograde orbit (LDRO) in the mid 2020’s, initial astronaut exploration and sampling of the returned material will take place as part of ARM. Subsequent human and robotic missions to the asteroidal material would also be facilitated by its return to cislunar space and would benefit scientific and partnership interests, expanding our knowledge of small celestial bodies and enabling the demonstration of mining of asteroid resources for commercial and exploration needs. The capabilities, systems, and operational experience developed and implemented by ARM and subsequent missions to the returned asteroidal material will advance NASA's goal of sending humans to deep-space destinations and eventually to surface of Mars. The robotic mission will also permit the demonstration of planetary defense techniques.

The robotic mission to capture a multi-ton boulder from the surface of a large NEA is depicted in Figure 3. The maximum boulder mass that can be returned is currently limited by the ARV xenon propellant capacity (~10 t) and the target asteroids available with orbits that allow returns in the mid-2020 time period. The maximum returnable mass is currently estimated to be approximately 40 metric tons. The capture system design has focused on retrieving a boulder that is 1-4 meters in size (up to a mass of ~70 t), but the design can be scaled to accommodate significantly larger boulders. This option includes the opportunity to demonstrate future planetary defense strategies on a hazardous-sized NEA. Inspired by the mission requirement to collect a boulder from the asteroid and thus dramatically augment the rendezvous spacecraft mass with in-situ material, the idea of the Enhanced Gravity Tractor (EGT) technique was conceived.

EGT uses mass collected in-situ to augment the mass of the spacecraft, thereby greatly increasing the gravitational force between the objects. The collected material can be a single boulder, multiple boulders, regolith or a combination of different material types using a variety of collection techniques, including the use of a separable spacecraft to “harvest” the material. Since the material would not need to be returned to Earth for an actual deflection mission, significantly more mass could be collected to provide mass augmentation than can be achieved during the ARM robotic mission. The mass of the collected material for actual planetary defense effort would likely range from tens to many hundreds of metric tons based on the size of the impactor and warning time available. Depending on the SEP system’s capability (i.e., power, thrust, and propellant) and the mass collected, the EGT approach can reduce the deflection times by a factor of 10 to 50 or more over the standard gravity tractor method, thus reducing the deflection times of several decades to years or less. The ARM robotic mission will provide the first ever demonstration of the EGT technique on a hazardous-sized asteroid and validate one method of collecting in-situ mass.

Due to the collisional nature of how NEAs are created, the presence of retrievable material is a virtual certainty. Although the EGT does require some period of interaction with the target, the vast majority of the time is spent in the gravity tractoring mode, which is done without direct contact. This paper describes a simple, single spacecraft EGT methodology to explain the basic concept. There are many possible approaches and synergies that could significantly increase the effectiveness of the EGT that are available for further investigation. For example, the use of one or more separable spacecraft to collect and aggregate asteroidal material, along with an enhanced, higher power version of the ARV to act as the EGT “tug,” would greatly increase the effectiveness of the technique and provide additional mission robustness. Additionally, the efforts to extract and retrieve resources from large asteroids for future exploration and commercial mining efforts would greatly increase our capability to obtain the necessary mass for an EGT deflection effort against a future Earth impactor. Finally, the ability of multiple spacecraft to orbit the target in formation to provide the necessary velocity change can further reduce the time needed by the EGT technique to divert hazardous NEOs. These are just a few examples. Many other ideas, including combining EGT with other deflection techniques, are possible.

Concept of Operations

Once in the proximity of a hazardous NEO, the EGT operations consist of five phases: 1.) initial orbit determination; 2.) characterization; 3.) material collection; 4.) tractoring; and 5.) final orbit determination. Having a spacecraft near the asteroid allows for very precise orbit determination and confirmation that the threat is an impactor prior to any interaction with the asteroid. If an impact is confirmed, the spacecraft can facilitate a refinement of the ΔV required in order to avoid a direct impact or any gravitational keyhole passages [4] that could result in an Earth impact during a subsequent encounter. Orbit determination can begin hundreds of kilometers from the asteroid and continue throughout the characterization phase. The characterization phase will begin during the initial approach and provide a detailed gravity field, shape model, and imagery of the asteroid. The imagery will be used to identify boulders and other asteroidal material to be collected. Gravity and shape models will be used by the spacecraft’s guidance and navigation system during the collection phase.

Material collection operations will depend on the spacecraft capabilities, as well as the targeted material to be collected. Depending on the type of asteroid, pre-launch knowledge and imagery of the surface, the size of the asteroid, estimates of required ΔV, warning time, and the amount and type of material (single boulder, multiple boulders, regolith, etc.) can vary. While this paper will not discuss in detail all of the possible capture mechanisms and operations, it should be noted that it is desirable to have a robust collection capability to sufficiently augment the mass of the spacecraft.

After collecting and securely restraining the asteroidal material, the spacecraft enters the tractoring phase. The EGT tractoring operations are similar to the standard gravity tractor with the spacecraft maintaining a constant distance (d) from the asteroid, countering the gravitational attraction by thrusting away from the asteroid with an equal force. Stationkeeping to maintain the desired orbit for any EGT method requires active navigation and awareness of the spacecraft’s relationship to the asteroid.

One way to achieve this standoff is having the spacecraft maintain a position along the asteroid’s orbital velocity vector. This in-line method, as shown in Figure 4, provides a simple navigation strategy with constant line of sight to the asteroid for range and position measurements. The thrust can then be adjusted to maintain the desired position. However, this method also requires canting of the thrusters in order to avoid pluming the asteroid. This requires additional propellant along with higher thrust to account for the cosine losses and thus increased power for electric propulsion (EP) system, or increased distance from the asteroid which would reduce the gravitational attraction and thus increase the deflection time.

Other methods have been proposed to increase the efficiency of tractoring. One of the most prominent is the spiral method. Figure 5 depicts this method in which the spacecraft enters a halo-like orbit around the asteroid’s velocity vector, creating a spiraling orbit when viewed in a sun-centered frame. This allows the spacecraft to decrease the distance (d) to the asteroid and increase the gravitational attraction while avoiding pluming the surface or requiring canting of the thrusters. By eliminating canting and setting the orbital period such that the centripetal acceleration counters the off-axis components of the gravitational force, the thrust required is equal to the net force along the velocity vector (v ⇀). This allows the full thrust capability of the spacecraft to be utilized in the deflection of the asteroid. The maximum deflection force is now a function of the mass that is collected and the minimum distance to the asteroid is set by risk posture, with thruster characteristics (e.g., plume angle, maximum cant angle, etc.) being a secondary consideration. While there are cosine losses introduced by the spacecraft not being aligned with the velocity vector because the resulting gravitational force is along the NEO-to-spacecraft line, these loses are overcome by the increased force as the spacecraft decreases the range to the asteroid which has inverse square relationship.

Asteroid Redirect Mission EGT Demonstration

The ARM robotic mission would demonstrate the EGT spiral method and one method of collecting material from a hazardous-sized NEA. Due to the mission objective of returning the collected boulder to the Earth-Moon system, this mission will not have the time nor mass collection capability to impart a ΔV of the magnitude that would be required for an actual deflection mission. However, all phases of the EGT operations will be demonstrated, including producing a deflection which is large enough to measure either with the vehicle still in the asteroid’s vicinity or via groundbased radar measurements if possible.

Assuming the target asteroid hasn’t been visited by a precursor mission, which would provide shape and gravity models as well as detailed imagery, the ARV will spend approximately 14 days during initial approach to transition from a 1,000 km acquisition point to 100 km range. During this time, initial shape and gravity models will be developed and imagery will be gathered to begin identifying potential landing sites. Over approximately the next five weeks, a series of six fly-bys will be conducted with a close approach range of one km and relative velocities decreasing from a meter per second to approximately 0.1 m/s. The first four fly-bys are targeted over different latitudes to build a detailed gravity model and gather <10 cm resolution global imagery. A two week hold will be used to process the data and imagery and identify potential collection sites to be targeted during the final two fly-bys. A final two-week hold will then be used to identify and prioritize three collection sites. Three sites are chosen to protect against the unknowns of the surface and boulder characteristics. A total of five collection attempts and three dry-run sequences over different collection sites have been budgeted.

The collection process begins with a series of dry-runs that are used to test and demonstrate the navigation and control systems. The ARV will rely on optical Terrain Relative Navigation (TRN) that will track landmarks that are mapped during the fly-bys. The first dry-run will start at a range of 5 km and follow a passively safe trajectory to an altitude of ~200 m. During this dry-run, both the LIDAR and TRN systems will be able to develop solutions that will be tracked prior to the execution of a pre-planned maneuver at the end of the dry-run. Once the navigation system performance is demonstrated, the second dry-run will follow the same passively safe trajectory but then continue to descend down to an altitude of 50 m. At that altitude, the ARV will match spin rates with the asteroid and maintain a stationary position relative to the target boulder for 10 minutes to demonstrate the TRN filter and the control algorithms that will be required for the final descent.

The final descent will again follow the same passively safe trajectory down to 50 m altitude at which point the ARV will maintain a local vertical descent through touchdown. During the final 20 m, use of the thrusters that plume toward the surface will be limited to attitude control only with no vertical velocity control in order to minimize any disturbance to the surface. At touchdown, the residual velocity will be attenuated by the Capture and Restraint System (CRS). While on the surface, as depicted in Figure 6, the CRS will provide stability while a small downward thrust is maintained in order to increase the downward force in the extremely low-gravity environment. Two robotic arms with microspine grippers with anchoring drills [8] will then grasp the boulder prior to the CRS providing a mechanical push-off that will separate the boulder from the surface, breaking any cohesion, and provide an initial ascent without pluming the surface. Once the ARV and boulder are clear of the surface, a propulsive maneuver will be performed to achieve a slow drift from the asteroid while the boulder will then be secured and a series of small maneuvers will be performed to determine the mass properties of the combined boulder and ARV.

With the boulder restrained and the mass properties updated, as depicted in Figure 7, the ARV begins to transit to an initial EGT spiral orbit. Much like the boulder collection dry-runs, prior to entering the final EGT orbit the ARV will demonstrate the EGT operations in an orbit with a range of one kilometer. This initial orbit will be held for about a week to demonstrate the TRN acquisition, control algorithms, and stationkeeping operations. The ARV will then transition to the final EGT orbit which will have a minimum altitude of one asteroid radius. During the EGT orbit, the ARV will track landmarks through the onboard TRN over two imaging arcs that occur just after crossing the terminator plane onto the illuminated side of the asteroid and just prior to crossing the terminator plane into eclipse. These imaging arcs will allow the system to precisely determine the ARV’s state and calculate any required updates to maintain the desired EGT orbit.

This final orbit will be held for a pre-determined amount of time ranging from approximately 30-90 days depending on the target asteroid and collected boulder mass. This will provide a small deflection, limited by the propellant and time constraints of the ARM robotic mission, while not drastically altering the trajectory of the hazardous-sized target. The ARV will then maneuver to a stand-off location where it will wait an additional four to five months for the deflection to propagate. This will allow the asteroid to achieve advantageous Earth alignment for deflection verification, which will be accomplished using ground ranging to the ARV combined with precise ranging from the ARV to the asteroid. Once the deflection is verified to beyond a threesigma uncertainty, the ARV and captured boulder will begin the transit to back to the Earth-Moon system. Depending on the target asteroid’s future Earth approaches and tractoring time available, there may be the opportunity to observe the deflection using Earth-based radar, allowing the ARV to begin the return transit prior to verification.

Comparison of Traditional and Enhanced Gravity Tractor Techniques

Compared to standard gravity tractor operations, without augmenting the mass, the EGT is more effective, and thus, requires less time to achieve the same amount of deflection. Since the gravitational acceleration imparted on the asteroid is independent of the asteroid mass, a simple consideration would expect the benefit to be constant and equal to the ratio of the spacecraft mass to the mass of the spacecraft plus collected material up to the point that the gravitational force reaches that maximum thrust capability of the SEP system. However, Figures 8 and 9 show that the deflection time benefit provided by EGT over gravity tractor is not just a function of collected mass and SEP power available for thrusting, but also the asteroid size. This is a result of the characteristics of the propulsion system. Assuming a constant asteroid density, as the asteroid size increases the thrust required to counteract the gravitational attraction increases. This increase in required thrust is provided by increased mass flow through the propulsion system and therefore more propellant usage. Including this propellant and accompanying increased tankage in the mass of the spacecraft introduces an asteroid size dependency in the ratio of the EGT to the GT systems which produce the slopes seen in the figures.

As shown in Figure 8, almost 30 times less time is needed for a 200 m spherical asteroid (assuming a density of 2 g/cm3) with a 50 kW EGT system that has a 4,000 kg dry mass and 500 t of collected material. As the asteroid increases in size, the propellant required increases the mass of the GT at a proportionately higher rate than the EGT. This leads to the slow reduction in benefit seen. However, even at these lower power levels the EGT can reduce deflection times by one to two orders of magnitude for smaller asteroids, which are much more numerous and harder to target with kinetic impactor techniques because of their size. Figure 9 shows that using the EGT with a 300 kW SEP system and 500 t of collected mass provides almost a factor of 50 reduction in deflection time for a 300 m diameter asteroid. If the collected mass is reduced to 100 t, the EGT is still almost 10 times more efficient. As asteroids get larger, these numbers decrease, but even for a 500 m asteroid, the EGT method with 500 t of material can reduce the deflection time by a factor of approximately 15.

The impact of SEP power and thrust can easily be seen by comparing Figure 10 with Figure 11, which provide an estimate of the EGT deflection time (years) and propellant (metric tons of xenon) required for a given diameter asteroid. The gravitational force is proportional to the product of the asteroid mass and the combined mass of the spacecraft and collected material, and it is also equal to the thrust required to maintain the relative standoff position and thus impart the ΔV on the asteroid. As one or both of these masses increase to the point the gravitational attraction equals the maximum thrust capability of the spacecraft, the spacecraft then must move further away from asteroid to decrease the attraction to a point where it can be balanced by the thrust. This decreases the efficiency of the tractoring and provides a limit that can be seen as the lines converge. This also leads to the observation that for larger asteroids the EGT does not provide a benefit over the standard gravity tractor without additional thrust capability. This asteroid size is a function of the vehicle thrust. For a 50 kW system with a nominal dry mass of 4,000 kg that provides 1.63 N of thrust, this limit is reached with a 650 m diameter asteroid (assuming a density of 2 g/cm3). Keeping these assumptions while increasing the power to 300 kW and the thrust to 9.78 N, the limit is increased to over 1000 meters.

There are a few additional, and more subtle, aspects of this comparison. One is the minimum allowable range from the spacecraft to the asteroid. For the plots shown, a minimum range of one asteroid radius above the assumed spherical asteroid’s surface was maintained. When this range is combined with the assumed plume divergence half angle of 20 deg., the cosine losses of the gravitational attraction that are inherent to the halo orbit method are set and add another dependence on the asteroid’s radius. Another is the dependency of the SEP specific impulse (Isp) on the throttle setting. This analysis assumed standard SEP throttle curves and a SEP system consisting of four thrusters that can produce a total 1.63 N. At maximum thrust, the SEP operates at maximum efficiency, however as the SEP is forced to operate at lower throttle settings, the Isp decreases. As the asteroid size increases, more thrust is required and the SEP thrusters can be used closer to their optimal efficiency which leads to the dips seen in Figures 10 and 11, most notably in the standard GT time curves. While these variables do have some impact on the EGT effectiveness, they are much smaller than the overall thrust level of the spacecraft or the ability to collect more mass, which is seen by the dips almost disappearing once the EGT collects a mass of 50 metric tons or more.

It can be observed in Figures 10 and 11 that the amount of SEP propellant required for the EGT is relatively insensitive to the amount of mass collected. Expanded scales for asteroids up to 400 m are shown in Figures 12 and 13. Figure 12 shows that even a 50 kW EGT system can allow deflection times of less than a year for impactors up to ~175 m in diameter. The standard gravity tractor requires 18 years for a 100 m impactor (red line in upper left-hand corner). Figure 13 shows that the xenon propellant for the EGT is significantly lower than the standard gravity tractor, due to the EGT operating at a higher thrust and Isp. The current ARV with a maximum Isp of 3,000 seconds and propellant capacity of 10 t would permit deflections of asteroids approaching 300 m depending on the amount of propellant needed to reach the target. Increasing the Isp while still providing sufficient thrust levels would be needed to reduce the propellant loads required, which likely become prohibitive, along with deflection time for the larger asteroids with lower SEP power. Going to higher power SEP systems, which is the goal of future human exploration architectures, can increase the size of asteroid targets as shown in Figure 11. Finally, it should also be noted that the above analysis did not assume a specific orbit and therefore did not adjust the power and thrust available based on solar range. The power and thrust levels stated are the assumed power and thrust levels during the entirety of the EGT operations.

Mass Collection Options

From all the data collected over natural bodies greater than 100 m in size, such as natural moons and asteroids, there are an abundance of boulders and regolith littered on their surfaces. Hence designing a spacecraft that is capable of insitu mass collection is a natural choice for deflecting asteroids using the EGT method. The in-situ utilization of the native asteroid also has the obvious advantage of avoiding the launch and delivery to the asteroid of a spacecraft with the equivalent mass of the EGT.

Mass for an EGT deflection mission can be collected in the form of boulders, rocks, or regolith from the asteroid surface using a variety of options with the goal of collecting as much mass as needed to maximize the effectiveness of the technique and minimize operational complexity and risk. To achieve this, several collection options are conceptualized.

Concept 1 – Collecting a Single Boulder

In the ARM robotic mission concept, the capture system is being designed to capture a single coherent boulder with a maximum mass of 70 metric tons. The collection of a single boulder of this size and mass is adequate for a demonstration mission, but future planetary defense missions would benefit from being designed to capture a larger, more massive boulder in order to achieve the necessary deflection in a given warning time. The ARV capture system is scalable to larger boulders, with a boulder on the order of 10 meters in size required to provide approximately 1,000 metric tons of in-situ mass.

Concept 2 – Collecting Multiple Boulders

The second concept is a natural extension of the boulder collection functionality demonstrated by the ARM robotic mission — being capable of collecting multiple boulders. Since the boulders are scattered on the asteroid surface, the spacecraft still picks up one boulder at a time. During the characterization phase, the spacecraft surveys the asteroid surface and maps out the locations of the target boulders and the associated local terrains. A number of boulders are selected based on the estimated sizes and masses, and the sequence of collection is determined. During the collection phase, the spacecraft approaches and lands at the first boulder site, and after one boulder is secured proceeds to hop to the next boulder, and so on. In the micro-gravity environment in the vicinity of an asteroid, hopping between boulders is not expensive in terms of fuel consumption. For example, it takes as little as approximately 0.28 m/s of ΔV to escape the gravity well of asteroid 2008 EV5, which is approximately 205 m in radius, and hopping on the surface takes far less ΔV than that. This concept is illustrated in Figure 14.

The single spacecraft design reduces mission complexity compared to concepts involving multiple spacecraft. However, there are significant challenges associated with this concept. First, the spacecraft has multiple capture mechanisms, and each of them has to function individually without interference. Depending on the size of the boulders, this can be challenging. Second, maintaining proper attitude to capture a boulder with other boulders without precisely known mass properties in tow is a challenging problem. Again, depending on the size of the boulders, the spacecraft may have to be tilted when approaching and capturing a different boulder, which may be limited physically because of the large solar arrays. Third, the Guidance, Navigation, and Control (GN&C) can be challenging. The dynamics associated with hopping combined with robotic capture mechanisms with large masses and the presence of large solar arrays are complicated. The sensor fields of view may become obscured by captured boulders, so additional maneuvers such as reorientations may need to be performed before approaching the subsequent boulders. Finally, significant portions of these operations will have to be performed autonomously due to the inherent communication delays.

Concept 3 – Separable Collection Spacecraft and SEP Tug

The third concept attempts to address some of the challenges associated with using a single spacecraft to pick up multiple boulders by utilizing two spacecraft. The main SEP spacecraft, or “mother ship” does not go down to the asteroid’s surface. This spacecraft is designated as a SEP tug and remains in proximity to the asteroid. A smaller spacecraft is designed for the single purpose of collecting regolith or capturing boulders and ferries between the surface and the SEP tug and transfers the acquired material to the mother ship. The collection spacecraft can be equipped with a smaller capture mechanism and does not require the large solar arrays that are needed by the SEP tug to power the ion engines. Therefore, it can be smaller, less massive, and more maneuverable than a single spacecraft that must perform both the collection and tractoring functions. This concept is illustrated in Figure 15.

The SEP tug will need to station-keep at some acceptable distance from the asteroid and must have the capability to receive and store the regolith and/or boulders delivered by the collection spacecraft. The SEP tug can hover over the collection sites to provide accessibility for material transfer or it can hover over the polar region to minimize the propellant required for matching the rotation of the asteroid while hovering, provided that the asteroid is a single-axis rotator. After enough mass is collected, the SEP tug moves into position for EGT.

The smaller and specialized collection spacecraft greatly reduces the challenges associated with the surface operations, including maneuvering and collecting the asteroidal material. However, there are challenges with this concept, most of which lie in the GN&C aspects and repetitive automated rendezvous and docking (AR&D) required by the concept. The collection spacecraft has to dock with the SEP tug in order to transfer the material, and the SEP tug has to be able to receive and store the material in the micro-gravity environment. This requires that the two spacecraft must be controlled precisely so that no collision occurs and the material is successfully transferred to the SEP tug. Rather than just storing the collected material, this concept also introduces the possibility of processing asteroidal material to extract propellants, such as magnesium or sulfur, which could be used by the SEP tug during tractoring operations. This would be particularly valuable for larger asteroids that require several hundred tons of propellant to be delivered to the asteroid.

The fourth concept deploys multiple collection spacecraft to collect asteroidal material and deliver it to the SEP tug. These collection spacecraft are likely smaller than the one envisioned in the second concept acquiring less mass during each collection operation. However, by having spacecraft scattered in a swarm fashion on the surface, this concept can access multiple areas simultaneously and can be more efficient in accumulating masses than a single collection spacecraft. In addition, having multiple collection spacecraft provides redundancy to ensure success of the mission. This concept faces the same GN&C and AR&D challenges as with the single collection spacecraft concept with the additional constraint of scheduling delivery of material to the SEP tug by multiple spacecraft. This concept is illustrated in Figure 16.

There are multiple variations and ways of implementing and combining these three basic concepts. Successful attempts to harvest asteroidal resources by NASA’s ARM and commercial entities (e.g., Planetary Resources, Deep Space Industries, and Kepler Energy and Space Engineering) will also have tremendous synergistic benefits for the successful implementation of material capture for a the EGT technique. Learning the basic techniques for mining material from larger NEAs will help improve the reliable operations needed to allow this approach to be successfully implemented for a future planetary defense effort.

Other EGT Operational Concepts

This section briefly discusses several other EGT concepts of operations that are of interest. These concepts assume that a SEP system is still the primary source of thrust that facilitates the deflection of the asteroid. When using a SEP tug for EGT, it is very important the SEP thruster plume not impinge on the asteroid. This requires that the SEP engines are either canted or the EGT is offset radially from the asteroid velocity vector. As discussed previously, canting the SEP engine reduces the efficiency and the effectiveness of the EGT due to thruster cosine losses, and thrusters that minimize plume divergence greatly benefit all operational concepts. Offsetting the EGT using the spiral tractoring technique also introduces cosine losses of the gravitational pull in the along-track direction. The concepts discussed here aim to improve upon the existing EGT concepts in the literature by alleviating some of the aforementioned shortcomings, by utilizing solar sails and tethers.

Figure 17 shows the concept of attaching a solar sail to the EGT spacecraft. The Solar Radiation Pressure (SRP) naturally pushes the EGT away from the sun, and thus, offsetting the EGT from the asteroid velocity vector. The solar sail can also be tilted so that a force component can be generated in the along-track direction to supplement the tugging force. The position of the EGT relative to the asteroid is an equilibrium resulting from balancing three external forces, gravity, SEP thrust, and SRP. An appropriate equilibrium can be established by trading the combined spacecraft mass, the size of the solar sail, as well as the solar sail tilt, given the thruster plume divergence angle.

Using multiple EGTs in formation can drastically improve the efficiency of the asteroid deflection. For example, Wie showed that placing n spacecraft in a halo gravity tractor orbit is n times more efficient in deflecting an asteroid. However, this requires tight control of the spacecraft positions to prevent them from colliding with each other as well as the asteroid’s surface. This issue can be mitigated if the spacecraft can be naturally separated. Figure 18 illustrates such a concept, which is a view of a 3-EGT scenario from behind the asteroid in the along-track direction. It can be seen that each of the three EGTs is attached to a solar sail, and by tilting the solar sails about the along-track vector, the forces in the cross-track direction separate the spacecraft naturally. These EGT spacecraft do not fly in a halo orbit in front of the asteroid. Instead, they are naturally held at their respective equilibria due to balance of external forces.

The effectiveness of the EGT operations is greatly dependent on the gravity component in the along-track direction. Thus, it is preferable to keep the mass close to the asteroid. Figure 19 illustrates a concept that keeps the augmenting mass on a tether. The augmenting mass can be placed much closer to the asteroid to increase the gravitational pull, to the limit of the SEP thrust capability, with much less mass while the SEP tug can be placed further from the asteroid for increased safety margin. Similar to the approach shown in Figure 17, a solar sail is used to provide the radial offset, and it can be tilted to augment the tugging force. The dynamics associated with the tether in the micro-gravity environment can be complicated, and need to be carefully analyzed.

Figure 20 shows a concept where the EGT is in-line with the asteroid velocity vector. This concept requires the SEP engines to be canted to prevent the plume streams from impinging the asteroid surface. This reduces the effectiveness of the gravity tractor due to the cosine loss of the SEP thrust in the along-track direction. For example, Lu showed a concept where the effective thrust for tugging the gravity tractor is only half of the total available thrust due to canting the SEP engines 60 degrees from the along-track direction. The concept here aims to reduce the cosine loss. As shown in Figure 20, the augmenting mass is attached to a tether, and kept close to the asteroid, while the SEP tug is kept farther away in the in-track direction. Because of the increased distance from the asteroid to the SEP tug, the SEP engines do not need to be canted as much as in the case where the SEP tug is closer to the asteroid, assuming the thruster plume angle remains the same. Clearly, this concept increases the efficiency of the EGT operation. Here, the mass can be kept closer to the asteroid than the scenario where the spacecraft and the augmenting mass are collocated. Thus, the same effectiveness of EGT can be obtained with a smaller mass. The challenge of this concept lies in the complicated dynamics associated with tethers in the micro-gravity environment. The complexity of station-keeping the mass and the interaction between the mass and the SEP tug need to be carefully investigated.

It is postulated that most of the boulders and regolith on the surface of an asteroid may be deposited by impacts from other small bodies. For example, Küppers shows that the boulders on the surface of asteroid Lutetia are mostly concentrated around the central crater in Baetica region, as shown by the images taken by the OSIRIS camera onboard Rosetta. This is consistent with the simulated distribution of boulders ejected from that crater. It is also theorized in Thomas that Shoemaker crater is the source of most boulders on asteroid 433 Eros. Boulders can also be created by thermal stresses. A larger structure can be fractured by the larger temperature gradients caused by crossing the terminator plane repeatedly. If these theories are correct, it is likely that most boulders should be loosely resting on the surface, with the forces keeping them on the surface being only the low gravity and cohesion.

Selection of boulder sites depends on many factors, which include lighting, communication links, asteroid rotation, etc. Here we touch upon the comparison of the sites on various latitudes in facilitating the boulder extraction only. All asteroids rotate in some fashion, with some tumbling (e.g., Toutatis) and others rotating around a single axis (e.g., Itokawa, 2008 EV5, and Bennu). For a tumbling asteroid, it is difficult to characterize the pros and cons of going to various sites on the surface. However, for the principal-axis rotators, it is evident for the few well observed asteroids such as Itokawa and Eros, many of the boulders congregate in the equatorial regions. This can be explained by the slow process in which the boulders shift to the equatorial regions due to the extremely small but persistent centripetal acceleration. Thus, the abundance of boulders makes the equatorial regions more favorable than others. In addition, the centripetal acceleration is the strongest at the equatorial regions, which can facilitate picking up boulders. For example, Figure 21 shows a comparison of the gravitational and centripetal accelerations at various latitudes on a fictitious spherical asteroid with a 250 m radius and a density of 2 g/cm3. The boulder is 20 metric tons, and the spacecraft is 9.7 metric tons (wet mass) at 20 m above the surface when capturing the boulder. It can be seen that if the asteroid rotates more rapidly than approximately once every 2.4 hours, in the equatorial regions, once the cohesion is broken, the spacecraft can fly away with the boulder naturally without the need for external forces due to the centripetal acceleration being greater than the gravitational acceleration (green and red curves). The benefit of the centripetal acceleration diminishes as the collection site moves up in latitude. If boulder to surface cohesion is low, which can be expected for a boulder resting on the surface, there are likely regions on the surface where collection operations could be greatly simplified.

Operational Challenges of Mass Augmentation

One significant operational challenge of the EGT method involves collecting the augmentation mass at the NEO. However, analysis that has been performed for the ARM robotic concept to date and the commercial interest in asteroid mining indicates that collecting many tons of mass from the surface of an asteroid is feasible and further analysis and concept development is warranted. The concept of operations currently being considered would provide the first demonstration of mass collection of the magnitude needed to successfully conduct an EGT deflection. Other collection techniques such as electromagnets, large quantity regolith collection, multiple boulder collection systems, and others have been envisioned and require further study and development.

The ARM robotic segment concept assumes that capture operations occur while the collection site is illuminated by the sun due to the reliance on optical navigation sensors and the desire to keep the ARV from experiencing an eclipse due to power, thermal, and potential charging issues. This constraint combined with the reliance on optical navigation during descent and the desire to maintain a passively safe trajectory as long as possible, sets a spin rate limit for accessible asteroids at a little over 3 hours. However, if a mission were solely focused on planetary defense, different designs could easily be envisioned that would remove or limit the reliance on optical navigation and/or allow the spacecraft to operate through an eclipse period that would relax this spin rate limit.

Finally, another concern about the spin rate is the existence of collectable material at the target. On small, fast rotators, the centripetal acceleration can exceed the surface gravitational forces leading to shedding of surface material and forming a monolithic body without any available material to collect. As shown in Figure 22, very few large asteroids have been observed to be spinning at a rate above the rubble pile “speed limit” rotation period of approximately 2.3 hours. A low cohesive strength of only 25 Pa can explain this observation. This leads to the conclusion that the vast majority of the large asteroids have the capability to retain surface material, and that material is likely to be loosely bound to the parent asteroid and readily collectable, thus making EGT a credible deflection technique for hazardous-sized impactors.

Applicability to Hypothetical Threat “ 2015 PDC”

We analyzed the ability of a 50-kW spacecraft like the ARV to deflect the 4th IAA Planetary Defense Conference hypothetical asteroid “2015 PDC” using the enhanced gravity tractor technique. There are two major challenges in this scenario for a gravity tractor. First, assuming that launch or departure from the Earth-Moon system is not possible earlier than spring 2017 (about a year after final observations are made), the impact date of September 2022 defined in this scenario leaves only 5.5 years to reach the asteroid and impart enough impulse to deflect it. This would be challenging for any slow-push/pull approach. Second, the asteroid orbit aphelion of 2.65 AU limits the available sunlight during parts of the diversion to only about 15% of the 1 AU insolation. This severely limits the power available for any technique that utilizes the solar power. Nevertheless, we found that there are some plausible solutions in which an ARV-class EGT can deflect the hypothetical asteroid 2015 PDC in the available time.

The only physical characteristic of the asteroid known at time of launch is the absolute magnitude, H = 21.3 ±0.4 (assumed to be one-sigma uncertainties). Depending on the albedo and density of the asteroid, this could correspond to a spherical-equivalent diameter from less than 100 m to more than 500 m, and a mass from less than 1 million tons to more than 100 million tons. The asteroid is more likely to be in the lower third of this range unless it has both a very dark albedo and the error in H makes it brighter than nominally predicted. As a test case we defined an asteroid with H = 21.7 (i.e. +1), albedo = 0.3, and density of 2.5 g/cm3 corresponding to a stony asteroid with a mass of 1.7 million tons. This is smaller and less massive than the most likely values, but within a reasonable range. The spherical equivalent diameter would be 110 m, but we assumed a 2:1:1 ellipsoid of the same volume as the predicted sphere, with dimensions of ~87 x 87 x 175 m. This non-spherical assumption is important because it influences how close to the asteroid the spacecraft can be, and the gravitational force is proportional to the square of the separation distance. We applied a constraint that the spacecraft should remain at least 100 m beyond the maximum dimension of the asteroid to avoid collision, corresponding to a minimum spacecraft-to-asteroid radius of 187 m when not thrusting, and radius when thrusting of about 200 m using the halo orbit approach defined and described earlier in this paper. Dense asteroids can be easier to move than larger low-density asteroids of the same mass, and spherical asteroids are easier to move than elliptical ones, because the gravity tractor can orbit closer to the center of mass and generate more gravitational force.

The force that can be applied to the asteroid is potentially limited by two factors. First is the available thrust from the spacecraft, based on the available power and the capacity of the propulsion system. Second is the gravitational attraction between the asteroid and the spacecraft plus collected augmentation mass. In most cases we investigated, gravitational attraction was the limiting factor, so it is more effective to collect as much mass as possible from the asteroid, up to an assumed limit of 1000 metric tons. It should be noted that this mass is greater than the current ARM robotic boulder capture system design requirement, so a modified capture capability would be necessary. This produced a net tractor force of approximately 1.0 N using the following equation from [9] (McInnes, C. R., “Near Earth Object Orbit Modification Using Gravitational Coupling”, Journal of Guidance, Control and Dynamics, Vol. 30, No. 3, 2007, pp. 870-873.):

  • FN – Thrust required to remain in the halo, also the thrust that the spacecraft applies to the asteroid-ARV system.
  • G – Gravitational constant
  • Mast – Mass of the asteroid
  • msc – Mass of the spacecraft with any mass augmentation
  • ρ – Radius of the halo orbit from the trajectory centerline
  • z – Offset distance of the halo orbit from the center of mass of the asteroid

It is assumed that the ARV spacecraft departs the Earth-Moon system with a characteristic energy (C3) of 2.0 km2/s2. This can be achieved by a spacecraft orbiting in high Earth orbit using a lunar flyby, or by a direct launch from Earth to escape on NASA’s planned heavy-lift launch vehicle known as the Space Launch System (SLS). The transit to the asteroid, shown in Figure 23 in green, takes 1,000 days and has a single 40 day coast period (shown in purple), though 10% power margin and a duty cycle of 95% allow for additional thruster off periods. Upon arriving at the asteroid on March 12, 2020, a three month long period of reconnaissance and mass collection is allocated before beginning the EGT operations. By thrusting for the next 824 days, the ARV is capable of deflecting the asteroid from the subterranean 2,790 km Earth periapsis radius (i.e., an impact) to 6,930 km allowing for a miss of 560 km altitude from the surface. In Figure 24, the trajectory of the ARV while thrusting with the asteroid is shown in green and the trajectory of 2015 PDC after deflection and subsequent Earth close approach is shown in purple. Given the very narrow miss distance margin, this scenario defines the limit of what this 50 kW-class vehicle can accomplish with the warning time and impactor orbit provided in the scenario and highlights the fact that more warning time and better remote characterization of impactors are highly desirable, particularly for slow-push/pull techniques.

As mentioned, the variables that affect the deflection are the time allowed to deflect and the maximum thrust that can be applied. The SEP system aboard the ARV is capable of 1.63 N of thrust and could be augmented with additional thrusters to upgrade the system, which would allow for a potentially shortened thrusting duration to reach the asteroid. Additionally, either larger arrays or new cell technology could take the maximum power at one AU to a higher level than the assumed 50 kW capability. More array power would allow the thrusters to operate at the maximum allowed halo thrust when farther from the Sun and would also allow for a shortened thrusting duration to the asteroid. Either of these vehicle modifications coupled with earlier detection would allow the ARV to be applicable to larger NEAs.

Warning Time and Compatibility with other Planetary Defense Options

As shown previously, a significant advantage of the EGT is that it can drastically reduce the deflection time compared with the standard gravity tractor. Although sufficient warning time is needed as is the case with all slow-push/pull techniques, EGT is a viable option when the warning time is measured in years, and not decades as is needed for the standard gravity tractor approach utilizing only the mass of the spacecraft. Figure 25 shows the approximate regimes of primary applicability of the four types of planetary defense techniques: civil defense, kinetic impactor, the traditional gravity tractor, and a nuclear explosive device. The EGT technique can significantly overlap the regime of the kinetic impactor, especially if a SEP spacecraft like the ARV has been developed and operated or if it has actually been launched and can be expediently refueled in space.

The pros and cons and the typical mission scenarios and constraints of classic techniques for planetary defense such as nuclear blast, kinetic impactor and gravity tractor have been well documented in literature, while the EGT is quite a new concept. It is also a very flexible tool in the hands of policymakers when they have to choose the reaction strategy. The simplest mission scenario for the EGT is that it is chosen as the primary reaction strategy as soon as the asteroid threat is discovered and sufficiently characterized: the spacecraft is launched, it collects mass from the asteroid, and performs the EGT deflection.

However, the EGT is also very much complementary to the kinetic impact and nuclear explosion techniques. Indeed, assuming that policymakers decide to implement a kinetic impact approach or opt to deliver a nuclear explosive device, if the primary mission does not perform with full success and is not completely successful in deflecting the impactor or leaves smaller parts of the original asteroid still with a risk of impacting the Earth, the EGT can provide trajectory corrections to the impactor or can collect mass from the smaller asteroid fragments and perform the EGT technique on them.

Additionally, in principle the EGT spacecraft can also provide in one single mission (one single spacecraft) the nuclear option. The spacecraft could also carry a nuclear explosive device and deploy it after collecting mass from the asteroid for subsequent policymakers will have to decide if the nuclear explosion option should be performed right away, or if the EGT can be performed first. If the nuclear explosion is taken as the first mitigation technique, the EGT can maneuver to safe distance while the explosion takes place, and then come back to check if the primary option worked properly, and perform corrections through the EGT technique on the main body and/or any smaller fragments that might still have a risk of impacting with the Earth.

It is likely that in the future there will be multiple ARV buses ready to launch and already operational in space, for example to deliver logistics supplies to astronauts in cislunar orbit, where the first ARV has placed the redirected asteroidal material, or to deliver cargo to the Mars neighborhood. Since the EGT technique builds on the ARV bus, the fact that there could be multiple ARV-derived buses available would make the EGT a ready to launch option. So ready that it might already be in space and simply be repurposed for its critical new mission of planetary defense. Finally, with the ability to be refueled, the ARV itself could be used as a kinetic impactor augmented by the mass collected during normal asteroid mining and processing operations.


The Enhanced Gravity Tractor technique is a novel, innovative variant of the traditional gravity tractor that can significantly reduce the deflection time required to be an effective planetary defense approach. Using mass collected in-situ, which would likely range from tens to hundreds of metric tons depending on the size of the impactor and warning time available, allows for significant augmentation of the tractoring mass and greatly increases the gravitational force between the objects.

NASA’s ARM robotic segment will provide the first ever demonstration of the EGT technique and validate collecting a multi-ton boulder in-situ. For an actual mission to deflect an Earth impactor, the collected material could be a single boulder, multiple boulders, regolith or a combination of different sources. There are many ideas for mass collection techniques and operational augmentations that can increase the effectiveness and reduce the operational risks associated with the EGT technique, and several have been highlighted in this paper. Depending on the impactor’s characteristics, the propulsion system’s capability and the mass collected, the EGT approach can reduce the deflection times by more than two orders of magnitude. Although the EGT still requires a significant warning time to reduce the required ΔV for the deflection, the ability to alter the trajectory more rapidly allows the EGT technique to be applicable to a greater range of impact threats. The ability for multiple spacecraft to orbit the impactor in formation can increase the ΔV than can be applied and further reduce the time needed by the EGT technique to divert hazardous NEOs.

Finally, the spacecraft necessary to successfully conduct an EGT deflection can also support other planetary defense techniques in a coordinated manner to maximize the successful deflection of a future Earth impactor. Advancements in SEP propulsion, autonomous vehicles, and robotic systems applicable to human and robotic exploration, commercial asteroid mining, and the used of space-based resources can synergistically help provide a robust defense against future Earth impacts.

Spaceguard in SciFi


(ed note: In John Lumpkin's Through Struggle, The Stars, he has the creation of an astromilitary the other way around. Initially none of the nations of Earth have a space presence, since there is no compelling reason to spend all that money on a space program when there are so many problems at home. The unexpected great asteroid strike of October 17, 2031 changed all that.)

The Rock — Common term for Southern Ocean asteroid strike that took place on Oct. 17, 2031. The asteroid, about 280 meters in diameter, came from below the plane of the Solar System and was undetected by the meager capabilities of the (mostly volunteer) orbit watch organizations at the time. It created vast tsunami that inundated the coastlines of western Australia, southeast Africa, and southern Asia. Fatalities were estimated at more than three million.

The event spurred Japan to develop a full-scale space program, initially aimed at preventing future potentially hazardous asteroids from striking Earth.


“Don’t tell me you’re busy?”

“Crushingly. Important?”

“No. I’ll be back later.”

The U.F.P. Justice hung in null-G, poised, as its burdened commander labored over the ship’s supercomputer terminal. Two hours ago, the call had come in: “Unauthorized asteroid deflection burn, Dec. -5.419°, R.A. 41.17°, class ξ asteroid 1999 RQ36 ‘Bennu’. Deflection Δv = 0.26±0.03 m/s.”

Small deflections make big changes. Even the emission of absorbed heat makes asteroids move unpredictably, unless their surfaces are mapped in detail. But with literally millions of asteroids, the Yarkovsky effect is not worth the bother.

But now someone has gone and moved one of them. A pretty big one, maybe half a kilometer on edge. That would probably utterly destroy one of Earth’s megacities, should it hit one.

Which means someone landed on it, did a thermographic survey, plotted its orbit to high precision, and then nudged it deliberately, in a particular direction, an exact amount.

So, the question–was it some unhinged terrorist bent on the obliteration of Los Angeles? Or a miner secretly moving a motherlode of priceless volatiles back to base?

In 51 years, he’d know for sure. For now, there’d be only guessing.


"If you guys just wanted to be left alone," said Murdoch, "why did you start the war? Why did you move Eros?"

"Ah, I see," said Vasily. "The propagandists have written your history books. We did not start the war."

"Like hell you didn't," said Murdoch. "Shifting Eros's orbit wasn't an act of war? It would have wiped us all out if it hit."

"Eros was an accident," said Vasily. "A few idiots who didn't double-check their math. We are not monsters, Murdoch. They never meant to aim the asteroid at the Pacific Ocean."

"Bad enough. And what's worse, you all banded up to protect Eros and make excuses for them, and when we asked you to help make sure it never happened again, you jerked us off."

"Your terms were impossible," said Vasily.

"Permits, Vasily," said Murdoch. "That's all we wanted. Is it that unreasonable? Each one of these rocks is a potential mass extinction event. Is filling out a form first that terrible?"

"Permits? No, they are not unreasonable," said Vasily. "An absolute veto for Earth over all orbital adjustments, no matter how minor or necessary? And the right to blow us out of the sky if we refused? No sovereign people would accept that."

"And war was worth that? It looks to me like that's what you ended up with anyway."

"Of course that's what we got," said Vasily. "You made us an offer we knew we would never accept, and then called it self-defense when you attacked us. It was imperialism. A smash-and-grab. You came, imposed yourselves on us, and forced us to mine your resources and buy the junk you made with it. You planned to do it for years, for decades. That's why you built your shining fleets. Do not try to tell me otherwise, good Murdoch. They had no purpose but to conquer us. Eros just gave you the excuse."

From THE LAST GREAT WAR by Matthew Lineberger (not yet published)

I thought I'd take the "spaceguard" idea one step further — if Earth has sufficient military power to punish the belters for any potentially dangerous orbit shift, they have the military power to rule the belters, period.

In the revised backstory, the asteroids were initially seeded by settlers when ships were too slow to make maintaining a military presence in the belt economical (the belters sent minerals to Earth in unmanned "slow boats" which were little more than chunks of ore with engines strapped on).

Then when the Zubrin drive was invented, the Great Powers suddenly had the means to extend their reach all over the Solar System, including the asteroid belt.

Vasily is largely right: Earth seized on a careless mistake as an excuse to conquer the asteroids and turn them into 19th century African colonies or Appalachia in Space — a place where poor local people dig out their natural resources at the behest of distant outsiders who "own" the land, get paid a pittance, and spend it on manufactured goods made by the same distant outsiders.

From Author's Notes to THE LAST GREAT WAR by Matthew Lineberger

Asteroid 624 Hektor was actually two bodies, a contact binary which had originally been 370 kilometers long. The Belters who'd first settled it nudged the two rocks apart and now 624 Hektor A and 624 Hektor B orbited Sol about ten thousand kilometers from each other. A was slightly larger than B, 190 kilometers long, the largest body in the "Greek camp" Trojan asteroids which preceded Jupiter around the sun at the Sol-Jupiter L4, and served as the capital and main settlement of the grandiosely named Republic of Hellas. B, 180 kilometers long, was leased to the United Nations for use as a neutral port strategically located between the inner and outer system, conveniently close to Jupiter.

The Hellans or Hellenics or whatever they called themselves (Fitzthomas couldn't remember and didn't care that much anyway) didn't particularly like having what amounted to a fleet base for half a dozen inner system Great Powers ten k-klicks from their capital, but they liked it better than frigates like New Jersey and her Chinese, European, Russian, Indian, and Brazilian counterparts roving through the Trojans blowing up their stuff. The Great Powers, in turn, didn't like anybody who wasn't as attached to Earth as they were with their grubby rock-rat fingers on the "Go" buttons of potential mass extinction events, but they needed the metals and hydrocarbons and water locked up in the rocks, and it was a lot cheaper to pay Belters to dig them out than to do it themselves. And Belters may have been pests, but they were equal opportunity pests. The Americans, Chinese, Europeans, Russians, Indians and Brazilians didn't trust their fellow Terrans not to steal all that loot for themselves and gain an insurmountable strategic advantage given a chance, and they were probably right not to. Belters only cared if they got paid.

So Hellas (and its counterpart at L5, the Aeneian Confederation) got to keep their independence and make money, the Terrans got their resources and carte blanche to blow the holy living hell out of any rocks that started moving without a permit, and the UN given the unenviable task of administering the whole thing. And it could have been worse for the Hellenics. The Aeneians had to share their capital of 617 Patroclus with the UN, with two settlements on opposite ends of the asteroid and spies scuttling out of the woodwork every time an Aeneian sneezed.

From THE LAST GREAT WAR by Matthew Lineberger (not yet published)

The High Guard was one of the few truly international organizations operating out of Earth, a multinational task force designed primarily to monitor the outer reaches of the solar system, track asteroids and comets that might one day be a threat to Earth, and to watch for nudgers. The Earth Confederation had grown out of an economic partnership between the old United States and a number of other nations, most of them former members of the British Commonwealth—Canada, the Bahamas, Australia, and New Zealand. Several non-Commonwealth states had joined later on— Mexico, Brazil, Japan, and the Russian Federation.

The High Guard, however, included ships from the Chinese Hegemony, the Indian States, and the European Union as well, which perhaps made that organization more representative of the entire Earth than the Earth Confederation itself.

The Earth Confederation had become more than an economic alliance in 2132, toward the end of the Second Sino-Western War. In 2129, a Chinese warship, the Xiang Yang Hong, had used nuclear munitions to nudge three small asteroids in Main Belt orbits into new trajectories that, three years later, had entered circumlunar space, falling toward Earth.

The Xiang Yang Hong had almost certainly been operating independently; Beijing later claimed the captain had gone rogue when he learned of the destruction of his home city of Fuzhou, and had carried out what was essentially a terrorist operation. His plan had been to devastate both the United States and the European Union by dropping all three asteroids into the Atlantic Ocean, causing devastating tsunamis that would wipe out the coastal cities on two continents. U.S. and European fleet elements had destroyed two of the three incoming two-kilometer rocks in what became known as the Battle of Wormwood—a reference to a biblical prophecy in the Book of Revelation that sounded eerily like an asteroid hitting the ocean. One rock—a piece of it, actually, had gotten through, falling into the Atlantic halfway between West Africa and Brazil.

The devastation had been incalculable. The loss of life, fortunately, had been less than it might have been, since most of the world's coastline cities were already slowly being evacuated in the face of steadily rising sea levels. Even so, an estimated half billion people had died, from West Africa to Spain, France, and England, to the slowly submerging cities of the U.S. East Coast, to the vanishing islands of the Caribbean, to the coastlines of Brazil and Argentina. The ancient term weapon of mass destruction had, with that single deadly blow, taken on a radically new and expanded meaning. Coming hard on the heels of the deaths of 1.5 billion people in the Blood Death pandemic, Wormwood's fall into the Atlantic had come close to ending technic civilization across much of the Earth.

The partial success of the American-EU fleet, however, had spurred further cooperation, and the rapid expansion of the automated High Guard project that had been in place for the previous century. Every space-faring nation on the planet—even the recently defeated Chinese Hegemony—had contributed ships and personnel to the newly expanded High Guard, with the sacred charge that never again would mountains fall from the sky. The Guard's motto was "A Shield Against the Sky." Its headquarters was located in neutral Switzerland, at Geneva.

Two centuries later, with the Sh'daar Ultimatum, the High Guard offered the teeming worlds and colonies of the inner solar system their best first line of defense against this new and still mysterious enemy. Their charter had been expanded; besides watching for nudgers—the ships of nation-states or terrorists attempting to push asteroids or comets into new and Earth-threatening orbits—they were tasked with patrolling the outer perimeter of the solar system, identifying incoming ships and, if they were hostile, engaging them.

The High Guard's oath, a solemn and sacred promise sworn before the souls of those who had died at the Battle of Wormwood, both in space and in the thunderous doom of the incoming tsunamis, offered the lives of the High Guard's men and women as a literal shield against any threat from the solar system's depths.

It was an immense task.. .one far too vast to be practical. The High Guard currently numbered about two hundred warships, most of them aging Marshall-class destroyers like the Gallagher, or the even older Jackson-class frigates. At any given time, at least half of those vessels were in port for refit, maintenance, and resupply. Typically, they deployed for nine months at a time, patrolling out beyond the orbit of Neptune, serving as backup to the half million remote probes in the forty-AU shell.

That arbitrary shell around Sol gave scale to what was lightly called "the vastness of space." The surface area of a sphere with a radius of 40 astronomical units was over 20,000 square Alls., .close to 450 quintillion square kilometers.

That worked out to one ship per four and a half quintillion square kilometers—an obvious impossibility. In fact, both patrols and remote sensors tended to be concentrated within about 30 degrees of the ecliptic, which cut down things a bit...but there was always the possibility that an enemy would sneak in from zenith or nadir, where tens of billions of kilometers separated one sentry from the next.

Thinly spread or not, in the thirty-seven years since the Sh'daar Ultimatum, not one alien vessel had approached Earth's solar system, and the general perception of the civilian population back home was that the war was far away, too far to be a threat.

According to the data flooding in through Gallagher's sensors, that illusion of security had just been ripped away. At least thirty Turusch warships had materialized almost seven hours ago, some six light hours out from the sun and 25 degrees above the ecliptic., .roughly in the same part of the sky as Arcturus and Eta Bootis. Exactly what they'd been doing since then was not clear; the ships weren't registering on long-range tracking, and no more data was coming through from Triton since that one, quick, burst transmission.

But Lederer could make a good guess. Confederation tactics called for launching a high-G fighter or near-c bombardment of the target immediately, so that local defenses were overwhelmed. It was possible that enemy near-c impactors were already approaching Earth.


     Salazar leaned forward. She mimed tapping behind her ear, twice, then sliced her throat with a finger.
     "We're in the clear, Salazar. No deepers, no syncing. Also," Rivera waved her hand towards the ruins up the mountain, "This place is a bit creepy. And so are you."
     "Tell me how much time it will take to rebuild the facility."
     "You couldn't have asked directly? We have to play cloak-and-dagger games?"
     "I don't want outside interference."
     Rivera frowned, then tapped her chin for several moments. "It's going to take at least six months to find the right people, who can tell us if it can be rebuilt. A year, if you insist on keeping it a secret. Then they need to determine if it can be rebuilt at all, and how."
     "This is asinine. We are talking about a 150-year-old technology."
     "It's not that we're more advanced, but that our tech is different. We might need production facilities that were abandoned a century ago. Until we understand how the whole thing worked, all bets are off."
     "Still asinine."
     "Honestly, it would be faster to tear it all down and rebuild. It wouldn't be cheap, and might take a few years to complete under the best of circumstances. We'd need to design the replacement, first, of course."
     "No good. It's bad enough that someone might notice construction crews, but if the dome is gone, outsiders will notice. We might be able to mask a retrofit as renovations, but we must give them something."

     "Why do you care what outsiders think? Who'd come up here?"
     Salazar pulled out a soiled piece of folded paper, and handed it to Rivera.
     "There's a souvenir shop in La Serena that sells these genuine antique tourist guides. I understand they make sure the guides are genuine and antique, with a concrete mixer full of gravel and some watered-down coffee. But they copy from actual historical guides. Tourists buy them, sometimes fully aware they're being ripped off. But some of the guides include sites that were long abandoned."
     "So I can see. Is it possible for me to keep this? If this is based on authentic information, this might be useful for the reconstruction."
     "Certainly. But you see the risk. I scouted the area before you arrived. There have been people here recently. Slobs. No respect. We can't be too conspicuous."
     "I'm curious — why all the secrecy? I would have expected you to welcome the tourist trade."
     "Mars. That's why."
     "I don't get it."
     "Do you realize how dependent A União do Sul is on Martian data? Without their observations, we are cut off from the heavens."

     "That's a problem?"
     "Not today, but you pay attention to the news, no? La Fuente is projected to take control of the Senate next month."
     "And you really think they'll break off relations with Mars?"
     "Maybe not right away, maybe not totally. But they don't see the value of the data, and if they did, they wouldn't trust the data anyway."
     "And this changes anything, how?" Rivera stood, stretched, looked up the mountain.
     "La Fuente is of course wrong. We need to know about any asteroids that could potentially devastate A União."
     "We already know all the important threats to Earth."
     "We know them now. We can't guarantee that it will stay that way. More importantly — we can't guarantee Mars won't change the facts."
     "Altering the data, you mean?"
     "Or altering the system. If I were Mars and had to wage war against any nation on Earth, I'd start hurling rocks. A small asteroid would be tricky to aim, but not impossibly so; difficult to stop on short notice; and impossible to survive. Smart nukes may as well be firecrackers."

     Salazar paused. "We need to watch the skies, independently. As far as we know, it might be too late — there could be changes in place, already. But we can ward against any sudden changes if we watch carefully."
     "We can launch space telescopes. That would be cheaper still."
     "They could see the launch, and they could more easily knock it out of the sky and make it look like an accident."
     "They wouldn't know what it did."
     "They might not take the risk."
     "Doesn't the Comity have their own satellites? Can't we just access their telescopes?"
     "The current détente won't survive La Fuente. When that goes, so does any data-sharing scheme — which, I remind you, is already under heavy scrutiny. People would notice."
     "An option, if I am honest, but not an option to rush to. We're trying to minimize diplomatic incidents. And, this is beside the point. You should worry less about what other avenues we've explored, and worry more about how to get that thing working again." Salazar pointed up the mountain.

     "Very well. I need a team to start the process. We'll do what we can, as quickly as we can. If we can salvage or recondition any of it, we will, and if we can't, we'll figure out how to replace it. No guarantees on anything, except our best efforts under these conditions."
     "Get back to me before bringing anyone on-board who might view this as pro- or anti-Fuente. This should be treated neutrally."
     "We'll be talking much, trust me. Everything these days is either pro- or anti-Fuente." Rivera shrugged. "Honestly? This is a tragedy. Of all the reasons to re-open this facility, fear should have never been among them. You'll find that experts largely agree. Including the ones we'll have to hire."
     "Will they refuse?"
     "Not the ones I'm considering, no. It's a chance to demonstrate their patriotism while serving science. You may find some dissenters in any community, but the opportunities here are immense beyond security concerns.
     "Very well. I'll trust you to weed out any potential troublemakers. This project is too important to risk."

     "Are we done, then? I'd like to go up and take a look around, myself."
     "Of course. Contact me in three days with an update. We can't afford delays." Salazar stood as a ground car stopped near the bench.
     Rivera waved. "We'll be in touch." She began the hike up the trail to the dome, browsing the tourist guide. "'Fully automated,' eh? Unless La Fuente outlaws deepers — God forbid — that part should be easy to emulate or outright improve.

     As she emerged in a clearing, she got her first glimpse at the the dome. There was a piece of truss jutting out, and a few velours missing. Then she saw the hole in the side of the building underneath. According to the brochure, it was the Vertical Platform Lift. That didn't bode well. It was awfully close to the main pier.
     Decades earlier, a group aligned with La Fuente de Luz destroyed this telescope, which once beheld the entire sky every night for years on end, as a symbolic attack on space-loving Oggs. Now, La Fuente has come to power. And they wanted her to rebuild what they blew up. It would soften their anti-science stance, and prepare a defense against enemies. It'd mean putting astronomers to work, and a chance to serve A União.
     It'd mean feeding into anti-Augment, Earth First rhetoric.
     Rivera was also pretty sure that saying no was not a serious option. Salazar was the kind of bureaucrat that treated everyone like a potential enemy until confirmed. And keeping a project of this scale, with this much symbolic power, a secret, was beyond her. She was no spy. She was an astronomer, for Christ's sake. What did Salazar want, a barrier with a polite note? A platoon? Several square kilometers of stealth fabric?

     She sighed. Public service mattered. Being the Science Advisor, mattered. The Interior Advisor's requests, mattered.
     She wasn't being asked to betray country or refuse science — on the contrary. This data will hopefully benefit all humanity, some day. And it could save lives.
     Rivera kicked a stone, then fumbled behind her ear. "Quincy, fetch a car, please?"
     It's the right thing, Rivera told herself on the ride home. It is. And it's inevitable. And it's a good thing. It is.



“Detain the operative,” Colonel Sansom had said in his message, sent to her over a confidential channel. Alonza had seen the woman’s file, stored under the name she was using. This was a matter Colonel Sansom should have handled himself, but he had left suddenly to go to an asteroid tracking station two days ago, to supervise repairs after a micrometeorite strike had damaged three telescopes, and would not get back to the Wheel for another thirty hours at least. A more easygoing officer might have sent la subordinate to the station, but not the obsessively conscientious Jonas Sansom. Tracking the orbits of asteroids that might threaten Earth was one of the most important duties of Guardians, perhaps the most important. Colonel Sansom would report to his superiors that he had seen to this task personally.

From FOLLOW THE SKY by Pamela Sargent (2004)
Big, flat, polyhedrals, 3000-8000m on a side, 300-1000m deep, three to 15 big annie plants. Battleplates are named for the big craters -- the sorts of events they exist to prevent (or, truth be told, cause.)

Battleplates were originally designed to protect planets from the sorts of events that create the geographical features for which the Battleplates are named. The student of geology should only need to hear names like "Chicxulub" (ref), "Vredefort" (ref), and "El'gygytgyn" (ref) to know that we're talking about large rocks landing where rocks ought not land.

While it might seem like overkill to have close to a hundred giant ships like these in one planetary system, that's because once you've moved all of the naturally occurring rocks-o'-doom from dangerous orbits, you begin to worry about someone else sending one at your homeworld from an oblique angle, and at velocities more typically associated with charged particles or recklessly-piloted warships.

Should a relativistic rock the size of a house hit your planet, it will ruin your entire (day geologic epoch). Battleplates, with their swarms of long-range, hypernetted sensor drones, are insurance against that sort of event. And with their massively overpowered annie-plants, they're good for all kinds of things, including the odd spot of intimidation.

From the BATTLEPLATE entry at Ovalkwiki, for the hard-science webcomic Schlock Mercenary

"Come here first. We'll do Lutetia, then you fly back and take care of the beanstalk. Tight timing, but it will work." Regulo was frowning. "Pity about the damned flight regulations. If they'd let me put a decent drive on some of the ships, I could halve your transit time. About a year ago I had Cornelia explore some financials for me. Did you know that half our resources are tied up all the time, just sitting and waiting for materials to get where we need them in the System? I'm not talking transportation costs, either. I'm talking about the effects of delays on budgets."

Rob shrugged. "I don't like the time it takes to travel around the System any better than you do, but we're stuck with it." Regulo was chewing on an old and familiar problem, and one where Rob could see little chance of changing the rules. His time would be better spent examining the changes they would need for the Spider.

"Trips out to the Belt aren't too bad if you have plenty of work to keep you busy," Rob went on. "You can't buck the laws of dynamics. Unless you can come up with a matter transmitter, we're stuck with transit times to match the drives. Your only other hope is the General Coordinators. Get them to change the laws on maximum permissible drive accelerations, and you'll be able to cut the transits."

From THE WEB BETWEEN THE WORLDS by Charles Sheffield (1979)

Launch Guard

The Launch Guard operates around spaceports, where launches occur (obviously).

At a spaceport, bulk cargoes can be launched with huge mass drivers. People and cargo can also be boosted into orbit using laser launch systems. Both of these can be used as ground-to-space weapons powerful enough for a planetary fortress. The Launch Guard controls these installations [a] to ensure terrorist do not hijack them as impromptu terrorist weapons of mass destruction and [b] to officially re-purpose them as weapons of mass destruction in order to wreak death and obliteration on any invading enemy spacecraft that unexpectedly appear.

If a spacecraft is on a collision course with something valuable or full of innocent bystanders (like the spaceport), or behaving erratically or suspiciously, the on-duty Launch Guard Range Safety officer will spring into action. They will trigger the off-course ship's integral self-destruct device or use surface-to-space weapons to blast it into smithereens. The range officer will have the agonizing task of weighing the lives on the ship with the lives at the projected impact point.

If civilian owned spacecraft have propulsion systems frightful enough to be weapons of mass destruction then by law all such ships will be equipped with destruct devices controlled by the launch guard. Just in case a tramp freighter with an antimatter engine has a drunk pilot and starts heading towards a major metropolitan area.

If the destructive energy is from the wayard ship's engine (e.g., antimatter) the self-destruct charge will just have to neutralize the engine. But if the destructive energy is the ship acting like an impromptu kinetic energy weapon, the closer the charge can come to vaporizing the entire ship the better.

Most real-world boosters and spacecraft include self destructs to prevent lawsuits and massive negative publicity if the rocket goes off course. Manned rockets generally have some sort of launch escape system to propel the habitat module clear of the blast radius (with the notable exception of the Space Shuttle).

The range safety officer with their finger on the big red button are usually located at some distance from the object they are blowing up. So they will have some objectivity (i.e., not hesitate because they are scared of committing suicide).


The good thing about starship disasters is that they so rarely turn into catastrophes.

Which is to say, sure, you can kill yourself, and you get your crew and your passengers killed, and if you try hard enough, you can go hurtling out of the system into the deep black at ludicrous speed, even while glowing with enough hard rads that no salvor’ll want to touch your hull for the next hundred thousand years. But space is big, its contents are small, and dramatic screw-ups that manage to take out other people by the mucker-ton therefore require sufficiently extraordinary talent that the Fourth Directorate will be crawling all over the site even before the wrecker gets there.

That is unfortunately not the case with interface vehicles, where the gravity well and the atmosphere bend physics all out of shape.

And you are flying, let me remind you, a real starship. Not some dinky aluminum-balloon sounding rocket that will obligingly shred itself into confetti and fireballs if the launch goes wrong; you’re flying maybe 3,000 tons of titanium composite and cerametals — not to mention the hot soup — that will come down hard, and will not come down happy.

This is a problem.

It’s not a problem for long. Well, if you’re flying the vehicle in question, it’s a problem for even less long, but you know what I mean.

Most dramatic engine failures happen very quickly indeed — on the pad, or within the first seconds of flight — at which point the starport disaster team will be on hand to clean up both you and your mess. And if you can keep things running long enough to get to orbital altitude — even on a suborbital trajectory — the odds are good in any kind of developed system that someone has a tug or a powerful OTV that can meet you and drag you the rest of the way upstairs while you get on the horn and have an unpleasant discussion with your insurance carrier.

That leaves the couple of minutes in the middle. Too high and fast for the starport to assist you; too low and slow for help from on high.

So what do you do, in that situation, if your main drive is failing and the auxiliary isn’t kicking in and you’ve got a sad board on all your backups?

Make sure you have the other kind of backup.

See, they don’t leave handling that sort of situation up to the Flight Commander. They know the sort of people who become Flight Commanders, and that they’ll try to save their ship right up until the very last second after it becomes a major incident. As is right and proper, but does not lead to the optimal outcome in this sort of case.

And they don’t leave handling it up to space traffic control, either, as they come from the same kind of dedicated stock that will try to save their traffic up to the very last second, too.

It’s in the hands of one man, titled Downrange Safety, who sits in a bunker at the starport. He has a live feed of all the traffic control instrumentation, everything he needs to see when a launch or landing trajectory has gone grossly off-track and out of safety limits. He has priority “flammifer exigent” access to the orbital defense grid, and to the starport’s launching lasers, and to anything else that might be useful.

He has a fully-automated system with executive authority to blast any incipient disasters right out of the sky, and he has a button which holds that system’s fire.

For three seconds at a time.

And that’s why I don’t fly interface vehicles.

– Svínif Kalyn-ith-Kalyn,
Sailing Master,
former Downrange Safety at Anniax Interplanetary, 6022-6167

From TWO MINUTES by Alistair Young (2015)

It is a truism of celestial warfare that among the most valuable targets to seize in the course of a major planetary assault operation is the primary planetary starport or local starports close to the intended target(s) of the operation. Starports, for all the obvious reasons, make perfect orbitheads, offering existing facilities eminently suitable for the landing and disembarkation of troops and materiel in quantity. (Orbital elevators, by contrast, are usually considered too fragile and susceptible to sabotage for this purpose, if the enemy are willing to absorb the ensuing damage to their own planet, until the orbitals and the continental area surrounding the elevator have been entirely secured.)

Why, then, are combat drops rarely, if ever, targeted at the vicinity of starports?

Again, it is important to remember that which is unseen. The popular image of starports is heavily biased towards the facilities for ground-landing starships — understandably, since the giant launch/landing pads built to handle nucleonic-thermal ships, with their blast-deflecting berms, “hot” shafts, and motile structures are some of the most impressive structures ever built — and towards the shuttleport terminals used by commuters and starship passengers alike. Nonetheless, the majority of cargo in the developed Worlds is carried by dedicated spacecraft incapable of atmospheric landing, to and from which cargo is transported in high volumes using suitably cheap methods: either laser-launch/deceleration facilities, mass drivers, or both, in which case the former handles light or delicate cargo and the latter hardbulk.

What this means in military terms is that, any other defense grid aside, the majority of starports in the developed Worlds have at their disposal a multi-gigawatt-range phased-array laser system, and/or a pair of mass drivers capable of accelerating a solid slug the size of a shipping container (or, equally effective, a shipping container packed with rubble or cheap heavy-metal ingots) to orbital velocities — both, admittedly, equipped with safety systems designed to prevent them from being used in exactly the manner which is desirable for military purposes, but that is something usually corrected readily enough by a software change — along with all the high-resolution traffic-control sensor equipment needed to target them effectively.

It is also a truism of warfare in general that one shouldn’t stab a heavily-armed man in the front. That is doubly relevant when the things they’re using as weapons are also the value that you want to capture.

— Elementary Principles of Orbit-to-Ground Maneuver Plans, pub. INI Press

Beam Transit Authority / Laser Guard

Huge solar power stations (SPS) can power MagBeams to push little spacecraft in near orbit or to give them a kick to another planet.

SPS can also power titanic laser arrays used for beam-powered propulsion for laser-thermal spacecraft all over the solar system. Especially since non-beam powered solar sails can only do about 3 milligees and you need at least 5 milligees to be practical.

They can also launch laser sail spacecraft on interstellar missions.

Such stations would be valuable and useful pieces of space infrastructure.

All of these provide advantage to people using spacecraft, but with the cost of being at the mercy of whoever owns the SPS. Ship captains have to file their flight plan with the SPS, and have to follow it to the letter or the beam cannot stay focused. And if your bill isn't paid up Beams-Я-Us will pull the plug. Sure Beams-Я-Us will need massive investments to construct the powersats and laser arrays, but it will be quite lucrative.

But then there is the awkward fact that a beam which could power a freighter far away in the asteroid belt is also powerful enough to vaporize a battleship in nearby cis-lunar space. Not to mention that any space garbage scow could suddenly become a laser spitting death machine with only the support of a powersat and a few half-silvered mylar balloons used as laser combat mirrors. You will have Powersat Weapons. The military will not be happy...

...Unless the military owns and operates Beams-Я-Us.

Naturally this can quickly turn into a Mutual Assured Destruction situation once there are more than one nation in the beam business. Which could sabotage efforts for the first beamsellars to get established. Solar power stations are such big targets and so very fragile. If any of the myriad nations of Terra felt threatened by the construction of a laser station, they could take out the billion-dollar station with only a sounding rocket and a bucket of gravel. There might have to be an international treaty forcing three or more nations to build large solar-powered laser arrays simultaneously.

In Rocheworld by Dr. Robert E. Forward the military had a series of such laser stations around Mercury. Given the plentiful solar energy each station could crank out a laser beam that was about 1.3 terawatts.

In Larry Niven's "Known Space" series, the warlike alien Kzinti gleefully attack our solar system, knowing that the pacifistic humans had no quote "weapons" unquote. This disaster was called the Kzinti Lesson. Among other things the Kzinti discovered the hard way was the fact that even though terrawatt lasers arrays used to push interstellar lightsail probes are technically "propulsion systems", nonetheless they can vaporize Kzinti warships like ants under a magnifying glass on a sunny day.


G. Harry Stine's (writing as Lee Correy) wrote a rocketpunk novel called Manna. In the novel, the military branches of the space-faring nations would like to put five gigawatt High Energy Laser (HEL) satellites in orbit. Using fancy techniques they are powerful enough to get their weapon laser beam through Terra's atmosphere and incinerate targets on the ground.

The trouble is the militaries want the HEL beamer satellites to be stealthy. The root of the trouble is that a five gigawatt HEL beamer containing a +five gigawatt power source is about as stealthy as a New York 4th of July fireworks display.

If only the power source could be at some distance from the HEL beamer, sending the energy by electromagnetic waves. You know, the same way a powersat sends microwave energy to ground power stations... hmmmmmmm.

That would work, the HEL beamers could be stealthy little dastards with no nuclear power plant, but rapidly unfurling a powersat reception antenna when it came time to zap something.

Now comes a bigger problem. Nobody can build any powerstats.

Why? Well, no corporation is going to embark upon a multi-billion dollar project like a powersat without insurance. And no insurance company is going to underwrite a multi-billion dollar installation which becomes a military target the instant it redirects its power beam from a power station in order to energize a HEL beamer. Especially a military target so huge, easy to hit, and incredibly fragile as a powersat.


How to solve the problem? Well, since it is an insurance problem, there should be an insurance solution.

Through a series of international agreements, the Resident Inspection Organization (RIO) was formed. This international group regularly inspected all powersats, and insured that they stayed pointed at ground power stations. In exchange, the insurance companies would underwrite the powerstats. If any powersat started to energize something that might be a stealthed HEL beamer, RIO would sound the alarm to all the astromilitaries, presumable giving the military units enough time to blow the living snot out of the powersat.

Naturally the astromilitary of Nation Alfa would be angry at RIO squealing when astromilitary Alfa tried to energize one of their HEL beamers. But astromilitary Alfa would be vary grateful if RIO squealed about astromilitary Bravo, Charlie, Delta or Echo doing the same thing.

     "I'm worried about RIO's reaction," Captain Kevin Graham remarked from the space port. "Our captains are concerned that PowerSat, InPowSat, and InSolSat powersats could have their power beams diverted to the American beam weapon stations on orbit . . . and we know where every one of them is stationed even though the Aerospace Force tried to hide them in inclined Clarke orbits."
     That was Top Secret information! How had the League of Free Traders found these battle stations, shrouded as they were with hard stealth technology?
     Ursila Peri reported from L-5, "I don't know if the powersat crews would carry out an order to redirect power beams to military battle stations. Whether the Aerospace Force has plans for a military takeover of the powersats is another matter, but such an attempt would put them in confrontation with the RIO teams on the powersats."...

     ...Vaivan went on, "Sandy, energy war isn't difficult to understand. Most low-tech countries will continue to do business with us in spite of any embargo or boycott. We provide value received and take very little off the top. The Tripartite may try to invoke sanctions against our customers by pulling their powersat plugs, but we'll be there with another plug. And we have a space port, space lift capability, primary metals and plastics industries, and the lunar mine and smelter at Criswell Center. You haven't see that yet, but it's just a lunar mine and smelter. Commonwealth Glaser's capable of supplying powersat electricity to anyone the Tripartite cuts off because they're now building powersats with lunar materials at a much faster rate than the Tripartite companies."
     "They'll react," I warned.
     "They'll go after your powersats."
     "In the face of international law and the Resident Inspection Organization? The insurance trusts won't stand for it," Wahak maintained. "Those trusts are controlled by the Tripartite, but not even a consortium of all the Tripartite banks could possibly cover the insurance losses. And there won't be any because the insurance trusts will place a rather strong damper on any military powersat takeovers. Then RIO will drive in the bung."
     "RIO teams are un-armed," I reminded him.
     "We'll see what happens when everybody shows their cards. RIO will have to become the first Space Patrol whether they want to or not because circumstances will force it ... and so will we."...

     ..."How much capacity has been dropped off the powersat net?" Ali tried to get back on track.
     "Fourteen gigawatts," Shaiko reported. "The cut-offs in­volved split beams, so no powersat is totally off-line, but One-Zero-Five-East and Six-Zero-East have near-zero loads."
     I didn't like that. "Which powersats will have near-zero if they pull the plug on Annom, Nireg, and Sorat?" I asked.
     Shaiko consulted a nearby display before replying, "Two-Zero-East and One-Zero-Five-East."
     "That drops One-Zero-Five-East down to zilch, doesn't it?" I observed.
     "Any load left on One-Zero-Five-East if Annom and Sorat go off?"
     "What are you worried about, Sandy?" It was Vaivan who caught my concern.
     "A ten gigawatt powersat can pump a big laser, Vaivan," I explained. "A high-energy laser—they're called hell beamers from their acronym, H-E-L—is limited in beam power density and range only by its energy source. If it's a self-contained unit, the space facility is large and vulnerable. But if a hell-beamer's energized remotely, it's small and hard to identify. Powersat One-Zero-Five-East could put its ten gigawatts into a hydrogen-fluoride hell-beam station to punch a beam right down to surface from GEO!"
     This was obviously news to them. Rayo Vamori broke the silence, "Is there a battle station over us?"
     "The Aerospace Force has them over all parts of the world in sixty-degree inclined geosynchronous orbits. Kevin Graham's captains have spotted them."
     Ali said slowly, "I'd better pay Peter Rutledge a visit."…

     …I went with Ali to the Resident Inspection Organization's headquarters, GEO Base Zero. Ali needed a pilot, and he wanted me to meet those upon whom the delicate stability of space power depended.
     I'd never known any RIO people. They kept to themselves as an anational paramilitary organization with a tradition of non-involvement. They had to be aloof. Thanks to RIO, there hadn't been a conflict in space since the Sino-Soviet Incident.
     Ali wanted to make certain that RIO knew what was happening with the powersats. He was also covering his anatomy by insuring that Powersat One-Zero-Five-East or any other powersat didn't get its power beam redirected to a hell-beamer.
     The approach to RIO Headquarters was a two-man job. The first challenge from RIO came at a thousand kilometers. We answered with the proper transponder code. Then we had to close at no more than ten meters per second, matching orbits and station-keeping ten klicks behind at zero closure rate. There we were thoroughly scanned. Once we proved we were sweet, pure, and unrefined as well as incapable of swatting a bee in revenge for being stung, they put a RIO pilot aboard. She strapped into the jump seat between Ali and me and flew the ship. It was rather disturbing to sit next to someone wearing about twenty kilos of Comp-X around her waist. From her accent as she reported on her comm set to RIO Approach, she was Japanese. I knew she wouldn't hesitate to self-destruct and take the ship and the two of us with her if we tried to ram GEO Base Zero...

     ..."He had to be. How much do you know about RIO and how it's run, Sandy?"
     "Only what I've read, which was reasonably extensive be­cause the Academy wanted future officers to understand RIO not as an adversary, but as a potential obstacle."

     The Resident Inspection Organization had been the factor which permitted the powersat network. Without non-national or international inspection, who was to know whether or not a powersat also contained a hell-beamer? Who could have ascer­tained whether or not an attack satellite was hidden in the structures of the photovoltaic panels? And who'd be sure that the power beam wouldn't be diverted—as Ali and I now feared— from the ground rectenna to an otherwise passive and silent hell-beamer satellite? Could someone really pirate the pilot beam that kept the power beam phased on the rectenna and then concentrate several power beams on an Earth or space target, even though the power density of a single powersat beam is only one-fifteenth that of a microwave oven?
     These questions left unanswered posed a military threat which in turn made a powersat a military target because nobody could take chances if an armed conflict appeared imminent.

     A powersat is a terribly vulnerable thing—square kilometers of solar panels and bus bars carrying megawatts of power. No businessman, entrepreneur, financier, banker, or investor would have risked a worn penny on a powersat that was a certain target in the opening moments of any future war. Neither Lloyd's nor Macao's would or could have underwritten the insurance re­quired for the long-term financing.
     Obviously, a non-political international inspection organization was required. But how could it be organized, financed, and operated to insure that it remained non-national? That had been an enormous problem.
     But technology always creates the new social organizations necessary to finance, manage, and control it.

     People hacked away at the problem until RIO was organized at the Hartford Convention. RIO was formed with the funding from the groups who'd lose the most if a powersat were attacked as a military target, whether it was an actual threat or not. The damage or destruction of a multi-billion dollar powersat would be an expensive loss to the insurance underwriters.
     The world needed space power and the insurance consortiums were the critical bottleneck. Whether or not there were economic pressures applied is a moot point today because the fraction of a percent that was tagged onto the kilowatt-hour consumer electric bill amounted to billions of dollars in insurance premiums which in turn more than paid for the 2,000 RIO inspectors and specialists with their independent communications and transportation systems.

     Rutledge had been accurate in using the sentry as the analogy for RIO.
     A lot of people didn't understand that an unarmed RIO was considered to be very effective. If a resident team or one of the ubiquitous spot inspection teams under the command of Rutledge found something unusual, there were two options open to the team leader: (a) report it covertly to RIO Headquarters for evaluation there; or (b) in a real emergency communicate the military activity to everybody. In the latter case, it was then important for RIO to get out of the line of fire.
     Because of its unique anational character and novel operational methods, RIO often acted in strange and unfathomable ways. Unarmed as they were, they posed no military threat to anyone. But the threat of their capability to saturate the comm/info network with the danger cry of the watch dog was a sure and certain restraint on military space activities. I suspected—and knew in some cases—that RIO had intelligence operations which penetrated deeply into nearly every military organization in the world. It wouldn't have surprised me, either, if their intelligence activities also embraced the world of commerce.
     A lot of military planners had spent a lot of time and effort drafting plans and programs for circumventing RIO. The Aerospace Force—whose job was ostensibly to keep and guard the peace, too—had a continual highly-classified think-tank activity going on "should it be necessary to activate such plans and programs." But the job of any military service is to ensure the security of its nation...

From MANNA by G. Harry Stine (1983)

Power beaming stations might well be dual purpose, the space age equivalent of the military frontier posts of the American west.

The military purpose would be to protect Earth from infalling asteroids or whatever military threat develops in deep space, but they pay for themselves by beaming power to cooperative targets like friendly shipping or energy receivers mounted on NEOs. Unless there is a red alert, shipping takes priority and even if the beam is interrupted, the ships continue to coast on predictable orbits and can be picked up after the interruption is resolved (repairs made, asteroid vapourized etc.)

Life in Fort Heinlein revolves around maintaining the solar energy arrays and maintaining the tracking systems, and life will be pretty tedious. Daily routine includes system checks and battle drills, and screw-ups get to go out and polish the mirrors under the first sergeant's unforgiving gaze. A secondary economy of service providers (saloons and whorehouses) will grow around the "fort" to service the crew, and other business might set up shop as well, everything from contractor repair depots to futures traders monitoring ship traffic and energy consumption.

Lightweight ships tapping into this system have torch like performance, economy traffic might go by cycler (although the "taxis" might need torch like performance to match the cycler or slow down to orbital velocity after dropping off) and bulk traffic will still go by low cost transfer orbits.

Santa Guard

If you are trying to establish a base or colony on a moon or other terrestrial body, you've got a problem. Such installations will require thousands if not millions of tons of pre-fab structures and support material. The tyranny of the rocket equation is going to make establishing the base more expensive than a mobster loan shark, because every gram counts.

This would be a perfect place to use in-situ resource utilization. But it is one thing to roast some gypsum to obtain some water. It is quite another to use local ores to create electronics and pressurized domes. Its not like there is a machine you can shovel dirt in one end and get habitat modules and stuff out the other.

Or is there?

Enter the Santa Claus Machine. You actually can shovel dirt in one end and get hab modules out the other. As long as all the chemical elements you need for the module can be found in the dirt. Such a machine will be priceless for creating planetary bases and spaceports.

But the trouble is such a machine can be a little too useful. It can make other stuff, like nuclear weapons, artillery lasers, unstoppable robot armies, and whatnot. Not to mention small items like undetectable counterfeit money. Heck, even the disassembler input stage is bad enough. It can quickly and easily turn tons of uranium ore into a lovely set of weapons-grade highly-enriched subcritical uranium ingots and a pile of waste uranium.

Blasted Santa Claus Machine is worse that a beam-propulsion array powered by a titanic solar power station. Unbelievably useful, but not the sort of thing you want in unsupervised civilian hands.

Well, lets use the same solution. Have them controlled by the military. Just like we have the Laser Guard in control of beam-propulsion arrays, we can have the Santa Guard in control of Santa Claus Machines. Also known as "Santa's Little Helpers."

So at the site of the proposed new base, the Santa Guard will emplace one or more Santa machines, and construct a secure housing where they can be kept under armed guard. The construction crew will submit blueprints to Santa Guard. The Santas will closely examine the blueprints to make sure they are not for weapons of mass destruction or other contraband, and supervise the printing. They will also be on the lookout for sub-units in several separate print runs that might be cleverly disguised components of a contraband item.

And in cases of illegal blueprints or illegal output, the Santas will do their best to arrest and bring to justice those who have broken the law.

Spacial Customs

Sovereign nations almost invariably impose controls on the import and export of trade goods (unless the nation is a freeport or something). The controls kick in when trade goods cross a magic line called the customs border. The border is patrolled by that branch of the civilian military called the Customs: collecting tariffs, halting or confiscating contraband, and apprehending smugglers.

If the custom border is located inside a spaceport, patrolling the boarder is the responsibility's of ground-based (or space station based) custom service. But if the custom border is drawn around the entire planet at orbital height, or even around an entire solar system / interstellar empire, then the job belongs to the space branch of the customs agency.

The primary difference is that the spacial branch zooms around in cutter-class spaceships, instead of wearing out shoe leather walking around the 'port.

Naturally the former branch is a bit more … exciting. Ground custom agent's main excitement is seeing the ship's captain break out in a cold sweat when you discover something irregular. By contrast space custom agents never know when that innocuous blip on the radar screen might abruptly turn into a life-or-death running gun-battle with a heavily armed smuggler spacecraft.

Ground customs also never know the gut-wrenching terror when a seemingly routine board-and-search operation turns deadly. Ground customs might not bother to carry sidearms, but space customs agents on a boarding mission invariably do. Otherwise they are just giving potential smugglers free hostages.

Ground customs agents just have to pound the pavement keeping an eye on the few openings in the spaceport's custom border. Space customs, on the other hand, may need to maintain constant deep space patrols of the huge border surrounding the planet/empire/whatever. The ease of the task depends upon the range and discrimination ability of the custom ship sensors.


     The artifact was the shell of a solid fuel rocket motor. Part of the Mariner XX, from the lettering…

     …If he sold the tank through the Belt, the Belt would take thirty percent in income tax and agent's fees. But if he sold it on the Moon, Earth's Museum of Spaceflight would charge no tax at all.
     Brennan was in a good position for smuggling. There were no goldskins out here. His velocity over most of his course would be tremendous. They couldn't begin to catch him until he approached the Moon. He wasn't hauling monopoles or radioactives; the magnetic and radiation detectors would look right through him. He could swing in over the plane of the system, avoiding rocks and other ships.
     But if they did get him they'd take one hundred percent of his find. Everything.
     Brennan smiled to himself. He'd risk it…

     …John Fitzgerald Brennan was very much the average Belter. Forty-five years of age. Two daughters—Estelle and Jennifer—by the same woman, Charlotte Leigh Wiggs, a professional farming machine repairwoman in Confinement. Brennan had the beginnings of a nice retirement fund, though he'd drained it twice for trust funds for his children. He had twice lost loads of radioactive ore to the goldskins. Once would have been typical. Belters laugh at inept smugglers, but a man who has never been caught may be suspected of never having tried. No guts.…

     …The center of goldskin police activity was the center of government: Ceres. Police headquarters on Pallas, Juno, Vesta, and Astraea were redundant, in a sense, but very necessary. Five asteroids would cover the main Belt. It had happened that they were all on the same side of the sun at the same time; but it was rare.…

     …he told him about a childhood in Confinement asteroid, and the thick basement windows from which she could see the stars: stars that hadn't meant anything to her until her first trip outside. The years of training in flying spacecraft—not mandatory, but your friends would think you were funny if you dropped out. Her first smuggling run, and the goldskin pilot who hung on her course like a leech, laughing at her out of her com screen. Three years hauling foodstuffs and hydroponics machinery to the Trojans before she'd tried it again, and then it had been the same laughing face, and when she'd bitched about it he'd lectured her on economics all the way to Hector.…

From PROTECTOR by Larry Niven (1973)

(ed note: the constraint is that the boarding actions occur in low to medium orbit, not in deep space. Author Grine_ is a moderator of Reddit's /r/hardsfbuilding and other subreddits)

So the traditional wisdom with respect to boarding tactics in space is that it's ridiculously impractical. I mean, combat occurs at Stupendous Range, it's all computerized anyway, yadda yadda. All of which is fine. But my setting doesn't quite work that way, for a variety of reasons: I've got thorium-nuclear and chemical rockets duking it out in low to medium orbit, for starters, and they're all using significantly crappier weapons than most hard-SF is used to. (This is all thought out quite extensively, and is a consequence of the universe's generally low tech-level and their FTL.)

Which gives boarders a chance in the first place, because approaching someone is actually possible. After all, you don't start that far from each other, and you're getting closer and closer very quickly. (Though something tells me that you'll want to approach prograde for any kind of docking or boarding action, since you're not trying to kamikaze them.)

I also had the idea that lasers (which are practical weapons in my setting) might be able to facilitate boarding actions. Of course, if you focus the death ray on them, you're going to blow shit up (it's called a death ray for a reason). But what if you take a continuous-beam laser and intentionally de-focus it? At low levels of focus, it's basically a sensor; focus it more, and it blinds enemy sensors; focus it even more, and you do generalized scorch damage, including destroying surface sensors and possibly maneuver thrusters. And, of course, you can blow them up if this is called for.

All of which sounds like a perfectly understandable and normal escalation of force for an encounter between a crook and a police spacecraft. The police scan someone, and use the information gleaned from that scan (and other sensors, and outside intelligence) to determine that this ship is suspicious. If the police believe that an inspection is in order, they can ask the ship to prepare for boarding. If they don't comply, the blinding starts; and if that fails, the scorching starts.

My assumption here is that the scorch damage will be able to disable the ship's ability to simply up and leave. If the scorch can disable engines, then a controlled boarding operation becomes possible, though it probably remains difficult.

My questions are:

  • Is this practical in the first place?
  • Could this situation result in an "equal" struggle between attackers and defenders? Or would this necessarily devolve into a hijacking where the defenders either surrender or go out with a bang?
  • Is this workable under combat conditions, rather than just police conditions?

(ed note: the constraint is that the boarding actions occur in low to medium orbit, not in deep space. This is a response to the question above. Author AntimatterNuke is a moderator of Reddit's /r/hardsfbuilding and /r/XenologyUniverse subreddits)

In any universe I can see some forms of boarding being possible. Say a group of terrorists or whoever seize a passenger liner and fly off with it. The pursuing space forces can't just vape it from Stupendous Range, there's hostages aboard. If they want to remove the terrorists, they must send people aboard. However this isn't classic swashbuckling-style boarding, while the terrorists could start shooting up the space marines as soon as they break through the airlock (and vice versa), it'd be far easier for the terrorists to threaten to execute hostages if boarding is attempted. The only sort of boarding that would occur would probably be something like a hostage negotiation team. So basically Speed IN SPACE.

The other type of boarding is taking control of a surrendered vessel. This happens in my universe, which is given over to the hard SF tropes of Stupendous Range Incredible Speed computerized combat. Inferior forces surrendering to you weeks or months in advance happens regularly during conflicts, and some people have built a whole military honor culture around it. But once again no one will actually shoot at anyone, it'd be a ritualized transfer of power, in which you put some of your people aboard the captured ship to ensure it stays captured, and take the enemy commander aboard your own ship.

If you want Space Swashbucklers, then as you say no side can have a great advantage over the other. However, I'm having second thoughts about this, because once your own people are aboard the enemy ship, you can't destroy it without killing them. To get around this you can move your own ships into close range so they can target specific parts of the ship, and have your swashbucklers wear armored space suits.

There are exceptions to every rule though, if there's some reason why you can't destroy the enemy ship or even risk firing on it (i.e. there is something/someone valuable aboard, or the ship itself is especially valuable), then you'll have to go in and manually remove the enemy crew.

That would still be an exception though, if you want boarding to be a regular feature of average combat, you need some way for all (or most) battles to end with a boarding. I'm going to guess the usual outcome of ship-to-ship combat must be both ships sustaining a roughly equal amount of damage, so in order to finish the battle you must approach and board the enemy ship.

So you'd use lasers to scorch the enemy's lasers and sensors, while taking similar punishment (you'll want both sides to have the same weapons range).

Here's how I think it would go:

  • One ship starts off with more delta-v capacity than the other, enough that it can run them down after matching orbits. Let's assume this is you, the attacker, for discussion purposes. Depending on how different your orbits are you might trade a few potshots as you try to get a long-range kill.

  • After you detect the enemy ship, you match orbits and start running them down from behind (i.e. traveling prograde). They try to run, but exhaust their delta-v capacity. Or they don't try to run and just prepare to fight. Either way the outcome is the same, it just takes longer.

  • (Aside) Since you're coming up on the enemy from behind you have to be wary of straying too close to their reactor. You could have a shielded command module, or you could come in ass-forwards, your shadow shield blocking their radiation, and your weapons peeking over it. Or maybe the enemy ship will point its nose at you to bring their weapons to bear, thus negating the problem. The enemy may draw things out by keeping their reactor pointed at you, or they may hide their engine if they consider it too vulnerable.

  • When you get close enough, the mutual eyeball frying and sunburning contest commences. You burn their sensors and lasers, they do the same to you. A few high-powered shots could destroy maneuvering thrusters. If you have missiles, those will get lobbed too. At close range they'll be deadly and hard to dodge, this might prompt a sudden end to the fight. But if you have countermeasures, or can target their missiles with your missiles, the fight continues. The latter case will have the interesting result of destroying all the missiles without damaging either ship. Presumably you want armor on these ships, so the low-power shots destroy the stuff on the outside but leave the ship and crew inside functional.

  • Now you have two ships with crippled weapons and attitude jets, drifting along on the same orbit pretty close together. The ship with the higher delta-v capacity could bug out now if it wants, if its objective was just to disable the enemy ship, not to capture it. But if you want to capture it you must board it. Your weapons are too damaged to threaten them with much punishment, so this isn't a "You have surrendered, I will send my people aboard to take control of your ship" situation.

  • You move in to board, feebly approaching with your crippled jets. If the enemy can move, they can draw things out again. If docking is too risky, just equip your swashbucklers with jetpacks and have them fly across.

  • Alternatively, attitude jets may be easy to armor--just hide them behind a little door in the armor. If that's possible then after all the weapons are disabled, you chase the enemy until they run out of propellant.

  • There may be a bit of a fight as your men make the crossing. The enemy may send people outside to shoot, in which case you can have part of your force hang back to provide fire support for the boarders. There will be an advantage in getting your boarders out the lock as fast as you can, to push the fight as close to the enemy ship as possible, and ideally inside of it.

  • Once aboard, your men seize control of the ship. If your boarders lose, or don't make the crossing fast enough, the enemy could end up boarding your ship, or both ships might be boarded by the other side simultaneously. Boarders will keep their space suits on; it's far too easy for the other ship to alter its breathing mix enough that anyone coming aboard without going through proper decompression will get the bends. People fighting the boarders may opt for suits as well, depending on how likely a hull breach is. So while one would think the swashbucklers would be huge testosterone-poisoned manly men, there may be an argument for using skinnier people, especially if powered armor/exoskeletons are available.

How likely is this to happen? Both sides must be evenly matched, so they both have motivation to build a more badass ship to roflstomp the other guy, but then the other guy can turn around and build an even more badass ship. This may actually be a very stable equilibrium because neither side will let their capabilities lag too far behind the other's. Since ships designed to fight in this way will take regular bloody beatings, the weapons, sensors, and everything outside the armor is probably modular and easily replaceable, so after a battle you go back to your supply ship, swap in new equipment, and touch up the armor.

Whether or not the boarding phase will happen depends on the orders given to both combatants and the particulars of the battle. Ships defending a planet or something else won't board attackers, since once the attackers are disabled they have nowhere to go for repairs. The defenders can just let them languish until they run out of air and voluntarily give up. But attackers will want to capture defender ships, since they can retreat for repairs.

Both sides could carry spare weapons and equipment. They can't effect repairs in battle, since anyone going outside will be cooked, but once battle is done they can use them to repair their ship AND the newly captured ship, which is now part of their fleet!

Laying out the requirements for boarding to happen:

  • Ships must meet for the first time traveling in roughly the same orbit. Given your engine tech trying to catch up with and board a ship orbiting in the opposite direction as you is probably impossible. The likely outcome of combat with that ship will be one of you getting perforated by kinetic buckshot moving at a combined dozen kilometers per second or so.

  • The attacker's delta-v capacity must be greater than or equal to the defender's. This might be true of any space combat, because if the defender has more, they can just run away or bug out once they've damaged the attacker enough.

  • The ships must be evenly matched, in number of ships and weapon strength. Otherwise the weaker side just surrenders.

This by no means guarantees a fight ending with boarding, it just makes it a viable tactic. I'm actually quite surprised that boarding seems eminently possible as long as you stick to these conditions, though a more rigorous analysis (i.e. crunch some numbers) would be called for in order to judge how prevalent it will be, relative to either destruction or surrender.

Your shields will affect this, I don't know if you've stated their exact capabilities, but I'd expect they'd make long-range kills harder, which is good, but draw out the close-in battle, which is bad but not horribly so. Your warp drive may throw a monkey wrench into this too, but I imagine a ship has to be precisely lined up before it goes to warp, else when it arrives it'll either go careening through the atmosphere of the destination planet or whizzing off into interplanetary space.

Bonus points: Ship design. A purely chemical ship designed for a boarding fight might resemble an armored sphere, with retractable doors protecting the weapons, airlocks, and engines. This will make it hard to defeat, depending on how strong the armor is it might be able to hold its own even against a nuclear-powered ship.

A ship with an atomic engine can't be armored all over, the radiation shielding would weigh too much. Maybe it would look like a cylinder or cigar atop a shadow shield with the engine aft of that. Presumably this ship will try to keep from exposing its engine to anyone it fights. If two of these ships fight they'll probably opt to point their noses at each other, which incidentally allows people to board without exiting the shadow-shielded area.


“There are two types of boarding action: non-contested and contested.

“The former is only moderately terrible: which is to say it is usually carried out in the course of routine inspections or interdictions, or after surrenders, and the starship being boarded has obligingly hove to when requested; one has been able to close with it without problems, and board it through the airlocks or by taking a cutter across; and in all other ways is being cooperative.

“In other words, if it goes wrong – which can happen quite easily even if everyone on the bridge is cooperating – it’s only house-to-house fighting, at point-blank range, in a maze, filled with fragile and dangerous industrial machinery, surrounded by vacuum, with hostile parties in control of the light, air, and gravity. If you’re lucky, no-one will be sufficiently in love with the idea of taking you with them to blow a hole in the reactor containment.

“And then there’s the difficult kind.

“There are actually very few contested boardings. Starship engagements typically happen at long range (light-seconds to light-minutes) and make use of weapons potent enough that surviving vessels are rarely in any condition to be boarded in any sense distinct from salvage and rescue. The exceptions to this general rule come when it is absolutely necessary to recover something valuable from the target vessel – be it hostages, a courier’s package, some classified piece of equipment, or the valuable data stored in the starship’s command computers – which will inevitably be destroyed if the vessel is forced to surrender.

“Achieving this requires a series of highly improbable operations to all go off perfectly in sequence.

“First, the approach: getting to the ship you intend to board; i.e., closing to suicide range, which may involve either surviving the fire from its cohorts, or cutting it out of its formation. This always, however, requires both surviving its fire while closing and depriving it of the ability to evade your approach and to take offensive action against the relatively fragile boarding party.

“So, in the course of matching orbits, you have to disable the drives, disable its weapons systems able to bear on your quadrant of approach, disable the point-defense laser grid (which can slice apart small craft at close range) and defense drones likewise, and disable the kinetic barriers that would otherwise hold off your approach to the hull; all of which you must do with sufficient careful delicacy that you don’t destroy the valuable part of the vessel that you want to claim in the process.

“Second, having achieved this, you must then board the target starship. In a contested boarding, you do not do this through the airlocks: they lead directly to designed-in choke points and people whose job it is to repel boarders, and if they retain attitude control, they can throw a spin on their ship that docking clamps won’t hold against. This is the job of the microgravity assault vehicle, affectionately known as the boarding torpedo, which serves to carry a squad of espatiers into an unexpected part of the target vessel – preferably near enough to the target within the target to make seizure easy, but not close enough to cause its destruction – by ramming, burning through the armor and the pressure hull, and crawling forward until an ideal position is reached or it can go no further.

“(This assumes that you are following the standard model, which people are constantly trying to improve on. One captain I served under rigged saddles for his AKVs and had us ride them to point-blank range of the target, then drop to its hull and take out the laser grid emitters directly. I would not recommend this tactic.)

“Then it’s guaranteed house-to-house fighting, at point-blank range, in a maze, filled with fragile and dangerous industrial machinery, surrounded by vacuum, with hostile parties in control of the light, air, and gravity.

“Third, you must do all of this very fast, for one reason or another. The above operations are not subtle, and your target will know you are trying to board them as soon as you start sharpshooting to disable. If you have terrorists or pirates, this is when they start shooting hostages. If your target is a military starship, though, as soon as they see a boarding attempt, the bridge, damage control central, and the maneuvering room all put one hand on the arming keys for their fusion scuttling charges, and as soon as any two of them conclude that they can’t repel boarders, they’ll scuttle. All you have to do is get sufficiently inside their response loop that you can punch them all out before that happens. (And once armed, it takes positive action to prevent the scuttling, so you can’t take the otherwise obvious short-cut.)

“All of which should explain why espatiers ship out with six times as many warm spares as their naval counterparts.”

– Maj. Esvan Solanel, the 22nd (“Alatian Highlanders”) Imperial Legion, Retd.

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