Introduction

Ever since the that prehistoric day the first wedge became the first knife (h/t to David Drake), people being attacked by sharp pointy things have thought some sort of protection would be a real good idea.

Thick clothing turned into ring mail, then chain mail, and finally plate armor in the desperate desire for an unpunctured epidermis. Knights in plate armor were reasonably well protected from sword slashes; but missile weapons such as longbows, crossbows, and primitive gunpowder firearms made plate armor increasing ineffective.

In the modern era, flak jackets evolved into bulletproof vests and hard-plate reinforced personal armor.

People designing modern hard-plate armor would do well to study historical precedents.

In science fiction personal armor was merged with man amplifiers to create Iron-man style powered armor. The ultimate high-tech body armor is the personal force field, though making a man-portable force field generator with a man-portable power supply is quite a challenge.


Traditionally in science fiction, physical armor defends against bullets and force fields defend against energy weapons.

Though occasionally you find interesting hybrids like the Traveller RPG anti-laser Reflec Personal Armor. This is little more than flimsy mirrored mylar clothing; great at stopping laser beams but worthless against bullets, edged weapons, or even nail-files.

In William Silent's Lord of the Red Sun aristocrats who were afraid of assassins armed with heat-ray guns would defend themselves by wearing asbestos capes. I'm pretty sure that despite its heat insulating qualties, an asbestos cape would provide little or no protection from a weapons-grade infrared laser beam. But I am 100% sure wearing such a cape will give you malignant mesothelioma or asbestosis (I'm not going to add links to the Wikipedia entries because the illustrations are horrific). In the real world asbestos has been replaced by fiberglass insulation, but that won't protect you from a heat ray either.

Physical Armor

In the real world, physical body armor is all there is. Non-physical armor is pretty much science fictional force fields.

Since everything old is new again, examining medieval suits of armor might prove instructive. Be sure to see this bit about King Henry VIII's space suit.

DILATANT

A dilatant (also termed shear thickening) material is one in which viscosity increases with the rate of shear strain. Such a shear thickening fluid, also known by the initialism STF, is an example of a non-Newtonian fluid. This behaviour is usually not observed in pure materials, but can occur in suspensions.

A dilatant is a non-Newtonian fluid where the shear viscosity increases with applied shear stress. This behavior is only one type of deviation from Newton’s Law, and it is controlled by such factors as particle size, shape, and distribution. The properties of these suspensions depend on Hamaker theory and Van der Waals forces and can be stabilized electrostatically or sterically. Shear thickening behavior occurs when a colloidal suspension transitions from a stable state to a state of flocculation. A large portion of the properties of these systems are due to the surface chemistry of particles in dispersion, known as colloids.

This can readily be seen with a mixture of cornstarch and water (sometimes called oobleck), which acts in counterintuitive ways when struck or thrown against a surface. Sand that is completely soaked with water also behaves as a dilatant material. This is the reason why when walking on wet sand, a dry area appears directly underfoot.

Rheopecty is a similar property in which viscosity increases with cumulative stress or agitation over time. The opposite of a dilatant material is a pseudoplastic.

Body armor

Various corporate and government entities are researching the application of shear thickening fluids for use as body armor. Such a system could allow the wearer flexibility for a normal range of movement, yet provide rigidity to resist piercing by bullets, stabbing knife blows, and similar attacks. The principle is similar to that of mail armor, though body armor using a dilatant would be much lighter. The dilatant fluid would disperse the force of a sudden blow over a wider area of the user's body, reducing the blunt force trauma. However, against slow attacks which would allow flow to occur, such as a slow but forceful stab, the dilatant would not provide any additional protection.

In one study, standard Kevlar fabric was compared to a composite armor of Kevlar and a proprietary shear-thickening fluid. The results showed that the Kevlar/fluid combination performed better than the pure-Kevlar material, despite having less than one-third the Kevlar thickness.

Four examples of dilatant materials being used in personal protective equipment are Armourgel, d3o, ArtiLage ( Artificial Cartilage foam) and 'Active Protection System', manufactured by Dow Corning.

In 2002, researchers at the U.S. Army Research Laboratory and University of Delaware began researching the use of liquid armor, or a shear-thickening fluid in body armor. Researchers demonstrated that high-strength fabrics such as Kevlar can be made more bulletproof and stab-resistant when impregnated with the fluid. The goal of the “liquid armor” technology is to create a new material that is low cost and lightweight while still offering equivalent or superior ballistic properties compared to current Kevlar fabric.

For their work on liquid armor, Dr. Eric Wetzel, an ARL mechanical engineer, and his team were awarded the 2002 Paul A. Siple Award, the Army’s highest award for scientific achievement, at the Army Science Conference.

From the Wikipedia entry for DILATANT
LIQUID BODY ARMOR 1

      The priority for body armour is to save the wearer’s life in the face of battlefield threats, from gunfire to blunt-force trauma in the event of an improvised explosive device detonation. But it’s not all about stopping bullets; there are many factors that affect how wearable armour is, which in turn impacts how and when it will be worn. If body armour is too heavy, bulky, restrictive or hot, it will diminish the wearer’s effectiveness in the field – a fact that quickly became apparent in Afghanistan.

The heavy weight of a soldier’s load became a serious issue during the Afghanistan campaign, where a programme driving concept of operations (CONOPS) and equipment rethink issues quickly became a priority. The ever-present threat of IEDs meant that soldiers needed to be protected by as much body armour as possible. However, the difficult terrain and harsh environmental conditions tested soldier endurance to the extreme, meaning that, while the onus remained on safety, new technologies were needed to minimise weight.

Moving towards modularity

A big change came when the US Army’s standard issue outer tactical vest was replaced by the lighter improved outer tactical vest (IOTV) in 2007, addressing the balance between protection and weight with a move towards greater modularity. Compatible with the newer, lighter and more protective enhanced small arms protective inserts (ESAPI) and enhanced side ballistic inserts, the wearer is able to armour the IOTV up or down as required, and the entire system can be released with the pull of a lanyard to allow the wearer to drop the load during water hazard incidents.

The US military’s next iteration of body armour will focus on reducing weight even further while increasing scalability to allow the wearer to adjust his equipment, depending on the threat level and mission at hand. The new torso and extremity protection system (TEP) in development at Program Executive Office Soldier is part of the new soldier protection system. It includes a modular scalable vest, ballistic combat shirt, blast pelvic protection system and a battle belt, which is aimed at getting weight off a soldier’s shoulders and onto the hips.

At its peak, the TEP will provide protection levels on par with the IOTV; its minimum level of protection will consist of wearing soft armour garments under uniform. The ballistic combat shirt is made of a breathable fabric, which has smaller ballistic protection parts built in and is to be worn under the TEP’s modular scalable vest. Soldiers also benefit from the blast pelvic protection system that has been designed to protect their thighs and groin against ballistic threats and burns. This system will be rolled-out in 2018 or 2019 following the completion of ballistic testing.

Liquid armour

Technology is moving on and military forces, like the US Army, are investigating new ways of keeping soldiers safe in the field.

Liquid armour is the leading big-ticket item in this area, with companies such as BAE Systems looking to apply the technology to emerging requirements. In June 2017, the company signed an agreement with safety and survivability technology company Helios Global Technologies to do just this. Liquid armour is a material that hardens very quickly when struck by a projectile at speed, in order to absorb the energy of the impact. It offers increased protection with reduced mass, wider area coverage, greater wearer manoeuvrability and can also be integrated with other systems, including being incorporated into standard Kevlar body armour.

According to BAE Systems, when combined with Kevlar, the reduced flow of the fluids in liquid armour restricts the motion of the fabric yarns, thus dispersing the energy of an impact over a larger area. The material is, therefore, less likely to distort than standard body armour, which generally bends inwards when a bullet strikes, preventing death, but causing considerable pain. Indeed, studies show that, when combined, these two materials offer ‘superior freedom of motion and a reduction in overall thickness of up to 45%’.

Smart fluids

Liquid body armour is also under development at MORATEX. The Polish company is working with the Military Institute of Armament Technology to apply the behaviour of a non-Newtonian fluid – which does not follow Newton’s viscosity law, instead opting for one where viscosity increases with the rate of shear strain – known as shear thickening fluid (STF) to body armour. When integrated into body armour as a protective insert, STF hardens upon impact and disperses the force of a blast or blow over a wider area of the body to not only stopping a bullet or projectile from piercing the body, but also to significantly reduce the shockwave from the impact, which can be as devastating to the body and internal organs as a bullet.

In addition to being lighter than standard ballistic inserts, and allowing a broader, more natural range of movement, materials with STF are proving to be more comfortable to the wearer. The US Army Research Laboratory has put STF-treated ballistic fabrics to the test to measure their breathability by assessing whether a fabric will allow sweat to be absorbed and then released through the fabric itself, in order to keep the wearer’s body temperature stable and prevent overheating.

The resulting report showed that while ballistic fabrics treated with STF showed a slight decrease in breathability compared with uncoated fabrics, the technology introduces ‘no significant penalty in breathability relative to conventional, uncoated ballistic fabrics’.

Liquid armour is a material that hardens very quickly when struck by a projectile at speed, in order to absorb the energy of the impact. It offers increased protection with reduced mass, wider area coverage, greater wearer manoeuvrability and can also be integrated with other systems.

Similarly, D3O has developed a number of armour products for defence from soft, flexible materials with high shock-absorbing properties. In their raw form, the company’s materials’ molecules flow freely, allowing them to be soft and flexible, but on impact, lock together to dissipate impact energy and reduce the transmitted force.

The company’s technology has been incorporated into a range of protective equipment, including vests for blunt trauma impact protection, seat pads for armoured personnel carriers and the TRUST helmet pad system. The latter is a seven-pad system – which uses a material called Decell – comes in the form of pads that are fitted to most ground combat helmets, including the advanced combat helmet, providing comfort and better deceleration under blunt impact. According to the company, its high performance exceeds the required level of protection by 33% in advanced combat helmet testing at 10ft a second.

Looking ahead, research is now beginning to move into even more futuristic arenas, from malleable fabric exosuits, lighter plastic materials to replace Kevlar and armour that can heal itself following a strike.

From EVOLVING ARMOUR: KEVLAR TO LIQUID by Claire Apthorp (2018)
LIQUID BODY ARMOR 2

The basic idea behind body armor hasn't changed very much in the past few thousand years. First, armor stops weapons or projectiles from reaching a person's body. Second, it diffuses the weapon's energy so that the final impact causes less damage. While it's not effective in every situation, armor can generally help protect people from serious injury or death, especially against the right weaponry.

Over the years, people have had to develop stronger and more advanced armor to protect against increasingly sophisticated weapons. However, in spite of these improvements, modern body armor still has some of the same shortcomings as ancient forms of armor. Whether it's made from metal plates or layers of fabric, armor is often heavy and bulky. Many types are rigid, so they're impractical for use on arms, legs and necks. For this reason, medieval suits of plate armor had gaps and joints to allow people to move around, and the body armor used today often protects only the head and torso.

­One of the newest types of body armor, though, is both flexible and lightweight. Oddly enough, this improvement comes from the addition of liquid to existing armor materials. While it's not entirely ready for combat, laboratory research suggests that liquid body armor has the potential to be a good replacement for or supplement to bulkier vests. Eventually, soldiers, police officers and others may be able to use it to protect their arms and legs.

The two primary types of liquid body armor currently in development both start with a foundation of DuPont Kevlar, commonly used in bulletproof vests. When a bullet or a piece of shrapnel hits a Kevlar vest, the layers of material spread the impact over a large surface area. The bullet also stretches the Kevlar fibers, expending energy and slowing down in the process. The concept is similar to what happens when a car air bag spreads the impact and slows the movement of a person's torso during a collision.

Although Kevlar is a fabric, Kevlar armor does not move or drape the way clothing does. It takes between 20 and 40 layers of Kevlar to stop a bullet, and this stack of layers is relatively stiff. It's also heavy — a vest alone often weighs more than 10 pounds (4.5 kilograms), even without ceramic inserts for additional protection.

Two different fluids, however, can allow Kevlar armor to use far fewer layers, making it lighter and more flexible. Both of them have one thing in common — they react strongly in response to a stimulus.

The term "liquid body armor" can be a little misleading. For some people, it brings to mind the idea of moving fluid sandwiched between two layers of solid material. However, both types of liquid armor in development work without a visible liquid layer. Instead, they use Kevlar that has been soaked in one of two fluids.

The first is a shear-thickening fluid (STF), which behaves like a solid when it encounters mechanical stress or shear. In other words, it moves like a liquid until an object strikes or agitates it forcefully. Then, it hardens in a few milliseconds. This is the opposite of a shear-thinning fluid, like paint, which becomes thinner when it is agitated or shaken.

You can see what shear-thickening fluid looks like by examining a solution of nearly equal parts of cornstarch and water. If you stir it slowly, the substance moves like a liquid. But if you hit it, its surface abruptly solidifies. You can also shape it into a ball, but when you stop applying pressure, the ball falls apart.

Here's how the process works. The fluid is a colloid, made of tiny particles suspended in a liquid. The particles repel each other slightly, so they float easily throughout the liquid without clumping together or settling to the bottom. But the energy of a sudden impact overwhelms the repulsive forces between the particles — they stick together, forming masses called hydroclusters. When the energy from the impact dissipates, the particles begin to repel one another again. The hydroclusters fall apart, and the apparently solid substance reverts to a liquid.

The fluid used in body armor is made of silica particles suspended in polyethylene glycol. Silica is a component of sand and quartz, and polyethylene glycol is a polymer commonly used in laxatives and lubricants. The silica particles are only a few nanometers in diameter, so many reports describe this fluid as a form of nanotechnology.

To make liquid body armor using shear-thickening fluid, researchers first dilute the fluid in ethanol. They saturate the Kevlar with the diluted fluid and place it in an oven to evaporate the ethanol. The STF then permeates the Kevlar, and the Kevlar strands hold the particle-filled fluid in place. When an object strikes or stabs the Kevlar, the fluid immediately hardens, making the Kevlar stronger. The hardening process happens in mere milliseconds, and the armor becomes flexible again afterward.

In laboratory tests, STF-treated Kevlar is as flexible as plain, or neat, Kevlar. The difference is that it's stronger, so armor using STF requires fewer layers of material. Four layers of STF-treated Kevlar can dissipate the same amount of energy as 14 layers of neat Kevlar. In addition, STF-treated fibers don't stretch as far on impact as ordinary fibers, meaning that bullets don't penetrate as deeply into the armor or a person's tissue underneath. The researchers theorize that this is because it takes more energy for the bullet to stretch the STF-treated fibers.

Research on STF-based liquid body armor is ongoing at the U.S. Army Research Laboratory and the University of Delaware. Researchers at MIT, on the other hand, are examining a different fluid for use in body armor. We'll look at their research next.

THE SLOW BLADE PENETRATES THE SHIELD
STF-based body armor has parallels in the world of science fiction. In the universe of Frank Herbert's "Dune," a device called a Holtzman generator can produce a protective shield. Only objects moving at slow speeds may penetrate this shield. Similarly, slowly-moving objects will sink through shear-thickening fluid without causing it to harden. In low-speed, or quasistatic, knife tests, a knife can penetrate both neat Kevlar and STF-treated Kevlar. However, the STF-treated Kevlar sustains slightly less damage, possibly because the fluid causes the fibers to stick together.

The other fluid that can reinforce Kevlar armor is magnetorheological (MR) fluid. MR fluids are oils that are filled with iron particles. Often, surfactants surround the particles to protect them and help keep them suspended within the fluid. Typically, the iron particles comprise between 20 and 40 percent of the fluid's volume.

The particles are tiny, measuring between 3 and 10 microns. However, they have a powerful effect on the fluid's consistency. When exposed to a magnetic field, the particles line up, thickening the fluid dramatically. The term "magnetorheological" comes from this effect. Rheology is a branch of mechanics that focuses on the relationship between force and the way a material changes shape. The force of magnetism can change both the shape and the viscosity of MR fluids.

The hardening process takes around twenty thousandths of a second. The effect can vary dramatically depending on the composition of the fluid and the size, shape and strength of the magnetic field. For example, MIT researchers started with spherical iron particles, which can slip past one another, even in the presence of the magnetic field. This limits how hard the armor can become, so researchers are studying other particle shapes that may be more effective.

As with STF, you can see what MR fluids look like using ordinary items. Iron filings mixed with oil create a good representation. When no magnetic field is present, the fluid moves easily. But the influence of a magnet can cause the fluid to become thicker or to take a shape other than that of its container. Sometimes, the difference is very visually dramatic, with the fluid forming distinctive peaks, troughs and other shapes. Artists have even used magnets and MR fluids or similar ferrofluids to create works of art.

With the right combination of density, particle shape and field strength, MR fluid can change from a liquid to a very thick solid. As with shear-thickening fluid, this change could dramatically increase the strength of a piece of armor. The trick is activating the fluid's change of state. Since magnets large enough to affect an entire suit would be heavy and impractical to carry around, researchers propose creating tiny circuits running throughout the armor.

Without current flowing through the wires, the armor would remain soft and flexible. But at the flip of the switch, electrons would begin to move through the circuits, creating a magnetic field in the process. This field would cause the armor to stiffen and harden instantly. Flipping the switch back to the off position would stop the current, and the armor would become flexible again.

In addition to making stronger, lighter, more flexible armor, fabrics treated with shear-thickening and magnetorheological fluids could have other uses as well. For example, such materials could create bomb blankets that are easy to fold and carry and can still protect bystanders from explosion and shrapnel. Treated jump boots could harden on impact or when activated, protecting paratroopers' boots. Prison guards' uniforms could make extensive use of liquid armor technology, especially since the weapons guards are most likely to encounter are blunt objects and homemade blades.

From HOW LIQUID BODY ARMOR WORKS by Tracy Wilson (2007)
LIQUID BODY ARMOR 3

His uniform is black as activated charcoal, filtering the very light out of the air. A bullet will bounce off its arachnofiber weave like a wren hitting a patio door, an excess of perspiration wafts through it like a napalmed forest. Where his body has bony extremities, the suit has sintered armorgel; feels like gritty jello, protects like a stack of telephone books.

It is a businessman making money. The orange and blue coverall, bulging all over with sintered armorgel padding, is the uniform of a Kourier. A Kourier from RadiKS, Radikal Kourier Systems. Like a bicycle messenger, but a hundred times more irritating because they don't pedal under their own power — they just latch on and slow you down.

From SNOW CRASH by Neal Stephenson (1992)
IMPACT SUIT 1

      He wanted to do it again. Nessus (a Pierson's Puppeteer) had the blood lust.
     He went up a rise, moving slowly, though his feet wanted to dance. He was weaponless, — but his suit was a kind of defense. No projectile short of a fast meteorite could harm him. Like a silicone plastic, the pressure suit was soft and malleable under gentle pressures, such as walking, but it instantly became rigid all over when something struck it.
     He topped the rise.
     The ship lights might have come from the Court Jester. They didn’t. Nessus saw the airlock opening, and he charged down the slope so the next rise hid him from view.
     The Kzinti ship was down. They must have landed with the gravity polarizer; otherwise he would have seen them. If they had then captured Jason on foot, he might still be alive. He might not. The same went for AnneMarie.
     Now what? The Kzinti ship was beyond this next rise of ice. At least one Kzin was outside. Were they looking for him? No, they’d hardly expect him here!
     He had reached the trough between the two swells. They were long and shallow and smooth, like waves near an ocean shoreline.
     The top of the swell behind Nessus suddenly sparkled with harsh blue-white sunlight. (The Kzinti are fooling around with some paleotechnology, and accidentally activates the self-destruct. Big kaboom ensues)
     Nessus knew just what to do, and he did it instantly. No point in covering his cranial bulge with his necks; he’d only get his larynxes crushed. The padding would protect his brain, or it wouldn’t. He folded his legs under him and tucked his heads tight between his forelegs. He didn’t have to think about it. The puppeteer’s explosion reflex was no less a reflex for being learned in childhood.
     He saw the light, he curled into a ball, and the ground swell came. It batted him like a beach ball. His rigid, form-fitting shell retained his shape. It could not prevent the ground swell from slamming him away, nor his brain from jarring under its thick skull and its extra padding.
     He woke on his back with his legs in the air. There was a tingly ache along his right side and on the right sides of his necks and legs. Half his body surface would be one bruise tomorrow. The ground still heaved; he must have been unconscious for only a moment.

From THE SOFT WEAPON by Larry Niven (1967)
IMPACT SUIT 2

      The instruments showed Earthlike atmosphere. Hardly surprising. Louis and Chmeee donned impact armor: leathery stuff, not unpleasantly stiff, which would go rigid as steel under impact from spear, arrow, or bullet. They added sonic stunners, translators, binocular goggles. The ramp carried them down into waist-high grass.
     “Do you know anything about projectile weapons?”
     “If we assume chemical propellants, a portable weapon will not penetrate impact armor. We can enter the tower via flying belts. Carry stunners. We would not want to kill our future allies.”

     Somebody yelled.
     The black-haired woman had dressed herself in shorts and shirt and a backpack. She held a projectile weapon at her side, pointed at Louis Wu. With her other arm she gestured and yelled again.
     Vacation was over. Louis became acutely aware that his hood was around his neck. If she tried a head shot—well, she might just give him time to pull the hood over his face, and then it wouldn't matter if she fired or not. The impact suit would stop the projectiles while he ran. What he really needed was the flying belt. Or did he?
     She tossed a heavy thing at Louis's feet. “Cut wood and build a fire.”
     Louis picked it up: a length of wood with a wedge of crude iron fixed to one end. “I hate to sound stupid, but what is it?”
     She named it. “You swing the sharp edge against the trunk till the tree falls down. See?”
     “Ax” Louis remembered the war axes in the museum on Kzin. He looked at the ax, then the dead tree … and suddenly he'd had enough. He said, “It's getting dark.”
     “Do you have trouble seeing at night? Here.” She tossed him the flashlight-laser. (Vala thinks the flashlight-laser is just a flashlight. She doesn't know it is also a laser weapon)
     “That dead tree good enough?”
     She turned, giving him a nice profile, the gun turning with her. Louis adjusted the light to narrow beam, high intensity. He flipped it on. A bright thread of light licked past her. Louis flicked it across her weapon. The weapon spurted flame and fell apart.
     She stood there with her mouth open and the two pieces in her hands.
     “I am perfectly willing to take suggestions from a friend and ally,” he told her. “I'm sick of taking orders. I got plenty of that from my furry companion. Let's be friends.”
     She dropped what she was holding and raised her hands.
     “You've got more bullets and more guns in the back of the vehicle. Arm yourself.” Louis turned away. He sliced his beam down the dead tree in zigzag fashion. A dozen logs fell burning. Louis strolled over and kicked the logs into a tighter pile around the stump. He played the laser into their midst and watched the fire catch.
     Something thumped him between the shoulder blades. For an instant the impact suit went stiff. He heard a single crack of thunder.
     Louis waited for a bit, but the second shot didn't come. He turned and walked back to the vehicle and Vala. He said to her, “Don't you ever, ever, ever do that again.”
     She looked pale and frightened. “No. I won't.”
     “Shall I help you carry your cooking things?”
     “No, I can … Did I miss you?”
     “No.”
     “Then how?
     “One of my tools saved me. I brought it a thousand times the distance light travels in a falan, and it's mine.
     She made a kind of arm-flapping gesture and turned away.

     Louis said, “Take the money and go. It'll make things easier for all concerned.” His hand was in his pocket, on the flashlight-laser.
     Filistranorlry held out a small bag. Fortaralisplyar took it, counted the contents. He walked through the soldiers and descended the stairway. When he was out of sight, Louis pulled the hood of the impact suit over his head.
     “I offer a high price. Twelve —” something untranslated. “You would not be cheated,” Filistranorlry was saying. But Louis backed toward the edge of the roof. He saw Filistranorlry signal to the soldiers, and he ran.
     The edge of the roof was a chest-high fence: zigzag iron spokes, carved to resemble elbow root. The shadow farm was far below. Louis ran along the fence toward the walkway. The soldiers were close, but Filistranorlry was standing back and firing his pistol. The roar was disconcerting, even terrifying. A slug slammed into Louis's ankle; the suit went rigid, and he rolled like a tumbled statue, picked himself up, and ran again. As two soldiers threw themselves at him, he swung over the fence and dropped.
     Fortaralisplyar was on the walkway. He turned, startled.
     Louis landed flat on his face, in an impact suit gone rigid as steel. The form-fitting coffin supported him, but he was still stunned. Hands helped him to his feet before he really wanted to get up. Fortaralisplyar put his shoulder under Louis's armpit and began walking them away.

From THE RINGWORLD ENGINEERS by Larry Niven (1979)
NEMOURLON

(ed note: Nemourlon is a handwavium super-Kevlar. Like Kevlar, Nemoulon is commonly used to make bullet-proof vests in the science fiction stories of Jerry Pournelle)

      I looked at my watch. Another hour of flying time. "Sergeant Ardwain."
     "Sir?"
     "Get them out of those work clothes and into combat leathers and armor. Weapons check after everyone's dressed." Dressed to kill, I thought, but I didn't say it. It was an old joke, never funny to begin with. I wondered who thought of it first. Possibly some trooper outside the walls of Troy.
     Hartz already had my leathers out of my pack. He helped me squirm out of my undress blues and into the synthi-leather tunic and trousers. The platform rocked as men tried to pull on their pants without standing up. It was hard to dress because we were sprawled out on our packs and other equipment. There was a lot of cursing as troopers moved around to find their own packs and rifles.
     "Get your goddam foot out of my eye!"
     "Shut up, Traeger."
     Finally everyone had his armor on and his fatigues packed away. The troopers sat quietly now. Even the old hands weren't joking. There's something about combat armor that makes everything seem real.
     They looked dangerous in their bulky leathers and armor, and they were. The armor alone gave us a big edge on anything we'd meet here. It also gives a feeling of safety, and that can be dangerous. Nemourlon will stop most fragments and even pistol bullets, but it won't stop a high-velocity rifle slug.

     Hamner laughed. "It's my pet worry at the moment. We don't have enough. Let's see, weapons …" The big man sprawled into a chair. He hooked one leg over the arm and ran his fingers through thick hair just receding from his large brows. "No military aircraft, hardly any aircraft at all except for a few choppers. No artillery, machine guns, heavy weapons in general. Mostly light-caliber hunting rifles and shotguns. Some police weapons. Military rifles and bayonets, a few, and we have almost all of them. Out in the streets you can find anything, Colonel, and I mean literally anything. Bows and arrows, knives, swords, axes, hammers, you name it."
     "He doesn't need to know about obsolete things like that," Bradford said. His voice was heavy with contempt, but he still wore his smile.
     "No weapon is ever really obsolete," Falkenberg said. "Not in the hands of a man who'll use it. What about body armor? How good a supply of Nemourlon do you have?"
     Hamner looked thoughtful for a second. "There's some body armor in the streets, and the police have some. The President's Guard doesn't use the stuff. I can supply you with Nemourlon, but you'll have to make your own armor out of it. Can you do that?"
     Falkenberg nodded. "Yes. I brought an excellent technician and some tools."

     The recruits learned to sleep in their military great-cloaks, and to live under field conditions with no uniform but synthi-leather battledress and boots. They cooked their own food and constructed their own quarters and depended on no one outside the regiment. After two weeks they were taught to fashion their own body armor from Nemourlon. When it was completed they lived in it, and any man who neglected his duties found his armor weighted with lead. Maniples, squads, and whole sections of recruits and veterans on punishment marches became a common sight after dark.

     There was less confusion than Howard Bannister had expected. It seemed an incredibly short time before the first men fell back in. They came from their barracks in small groups, some in each company, then more, a rush, and finally knots of stragglers. Now in place of bright colors there was the dull drab of synthetic leather bulging over Nemourlon body armor. The bright polish was gone from the weapons. Dress caps were replaced by bulging combat helmets, shining boots by softer leathers.
     "Small arms and mortars, nemourlon under license from DuPont; weapons are one of our main processed exports, along with intermediate-technology equipment for planets even less industrialized than we are. We can make armored cars and tanks, but there won't be a lot of output. No electronics to speak of; we've been negotiating with Xanadu and Meiji for chip fabricators, but …" He shrugged again; everyone knew the prices were kept artificially high. "We have the people and the knowledge, energy and resources and opportunity, all the classic requirements, but we're at the tools-to-make-the-tools-to-make-the-machines stage.

     Since the development of the metallic cartridge, smokeless powder and the self-loading firearm, small-arms development has gone through a number of cycles. The original generation of magazine rifles were the result of a search for range and accuracy; they were bolt-action weapons, capable in skilled hands of accurate fire at up to several thousand meters. In the opening battles of the First War of AntiGerman Encirclement (1914-1918), the professional soldiers of the British Army delivered deadly fire at ranges well in excess of 1000 meters, at the rate of twelve aimed rounds per minute — leading the officers of the opposing Imperial German formations to suppose they were the targets of massed machine guns! By the 1930s, these bolt-action rifles were being replaced by self-loading models firing identical ammunition and of roughly comparable performance.

     However, the mass slaughters and hastily trained mass conscript armies of the 20th century rendered the long-range accuracy of such weapons irrelevant. Studies indicated that virtually all infantry combat occurred at ranges of less than 800 meters, and that in any case most casualties were inflicted by crew-served weapons, particularly artillery. Accordingly, beginning with the Wehrmacht in 1942, most armies switched to small-calibre assault rifles capable of fully automatic fire but with effective ranges of as little as 500 meters; in effect, glorified machine pistols. For a few decades, it appeared that laser designators would provide an easy answer to the problem of accuracy, but as usual with technological solutions countermeasures limited their usefulness to specialist applications.

      Two developments brought the return of the long-range semiautomatic infantry rifle. The first was the development of first kevlar and then the much more efficient nemourlon body-armor. Nemourlon armor of reasonable weight resists penetration by most fragments and any bullet that is not both reasonably heavy and fairly high-velocity. Since modern body-armor covers head, neck, torso and most of the limbs, experiment has proven that a cartridge of at least 7x55 mm is necessary for adequate penetration; such a round renders an infantry rifle of acceptable weight uncontrollable if used in a fully automatic mode. The second factor was the gradual decay of the mass, short-term conscript army, as small forces of highly trained professionals once more became common. Sufficient training-time for real marksmanship was available in these forces — thus increasing their advantage over less well-trained armies still more.
     
     He looked around, fighting the savage pain when he breathed, feeling at his stomach and chest. The covering of the armor was ripped, and he could feel the heat of the flattened disks of lead alloy embedded in it, digging into his skin where the tough material had dimpled inside as it came close to parting. One of his ribs might be — was — cracked, but the nemourlon had stopped both rounds. It was supposed to be proof against pistol-calibre, but that had been awfully close … a good thing the local arms industry doesn't run to tungsten. (tungsten is denser than lead, so it has better penetrating power. However it is much more difficult to machine into bullets)

From THE PRINCE by Jerry Pournelle and S. M. Stirling (2002)
HIDDEN ARMORED VEST

      The innkeeper looked at the cases the security detail had opened. Like those of Barbour and Daun, they were filled with equipment. This time, all the equipment was lethal.
     Margulies and Vierziger began handing out weapons to the rest of the team.
     Vierziger handed each member of the survey team a vest woven from beryllium monocrystal. Moden and Daun had carefully lifted the segments of ceramic plate from the exterior walls of the luggage. The plates fitted into pockets in the vests, forming body armor almost as resistant as the clamshell hard-suits which the FDF issued for normal field operations.
     Coke took off his loose outer jacket and paused. "I don't think I want armor for this," he said. He was —
     Well, of course he was frightened, a turtle would be frightened if it was about to walk into this one. It was his job, and anyway it'd be all right.
     "I think you ought to wear it, sir," Margulies said.
     She'd completely emptied the suitcase on which she'd been working. Weapons and ammunition lay in neat stacks on the tile floor around her. She stood up and latched the case, then twisted the hand-grip 180°. She slid the luggage over to him.
     "I think he ought to wear armor also," said Johann Vierziger, "though I'll admit I wouldn't myself if it were me."
     He smiled. His face was that of an ivory angel. "I prefer the freedom. But what I really think is that I should be the one to go outside, Matthew."
     Coke shook his head forcefully. "Its my job," he said. "And anyway, it'll be all right."
     He thrust his arms through the holes of the vest he'd prepared, then mated the front closures. His outer jacket was cut to hang the same whether or not there was armor beneath it. He pulled it on.

From THE SHARP END by David Drake (1993)
DURASTEEL PLATE ARMOR

(ed note: This story is part of the War World series which starts off with the decline and fall of the first empire. On the planet Haven, off-world trade is all but gone, the colonists have to make do with what is locally available. In particular the miracle handwavium armor alloy "durasteel" cannot be created on planet, whatever is currently present is all there is ever going to be.

The Haven government is printing paper money like nobody's business, causing a bad case of hyperinflation. 20,000 Haven marks to buy a single loaf of bread. Silver and gold bullion is the only money that is worth anything.

One protagonist is Albert Hamilton, Baron of Greensward. He views the rise of bandit gangs and the decay of government with alarm. Not to mention the evil politicians at the capital with ambitions of becoming warlords. As it turns out his barony has a secret stash of silver and gold bullion. He has started projects to turn Whitehall manor house into a veritable medieval castle-fortress, to better defend the villagers of the barony. Because the government ain't gonna do it. He also has other plans.

Brigadier Gary Cummings of the 77th Imperial Division's Second Regiment is in charge of the only government troops on Haven. They are the only thing standing against the bandit gangs and the fall of civilization. But due to hyperinflation, he has no money to pay for troops. He has to disband several units.

So Brigadier Cummings goes to see his old friend Baron Hamilton with a proposal for their mutual benefit. Turns out the Baron has a better one.)

      The Baron knew where the bitterness in Cummings’ voice came from. He’d talked himself blue in the face—even before the Marines started leaving—trying to get the Castell spaceport fortified, then watched as it was wrecked by thugs in a few days.
     (Brigadier Cummings) “Manpower isn’t good. We only have two regiments, both at something like three-quarters strength. The raid cost us. Not that we didn’t eliminate about a third of the Castell’s gang members and thugs. Of course, there’s plenty more where they came from. The rest of it’s this cursed inflation. I can’t really crack down on soldiers who desert to take care of families, not when I can’t feed and clothe them properly. But, Albert, maybe you can help me do something about that. Apart from your flocks and herds, I understand you’ve got quite a cache of silver and gold bullion stashed—”
     (Baron Hamilton) “Where the devil did you hear that?! It couldn’t have been the servants; after all, only Mattie and John knew about it. I can’t imagine they’d talk—no, I won’t believe it. He couldn’t have!”
     “As a matter of fact, John didn’t. It was George Morris at the First Imperial Bank.”
     “That rat-bastard—!”
     “Brigade Security had someone planted at the bank to keep an eye on where the money was going and he did his homework. What could George say, when I laid my cards down on the table? He knew you’d be mad as all get-out, but he stands to lose a lot if the militia can’t meet its payroll.”

     The Baron shook his head in weary disgust. “So, what do you have in mind?”
     “First of all, I’m not here to rob you. I’m desperate, not stupid. I’d like to propose a deal that should make us both reasonably happy. Al, I know you did your ten years in the Imperial Navy and you can count fingers held up before your face. If we have to pull all the troops out of Castell City to someplace else where we can feed them, what would you give for the Central Valley’s chances by next summer?” (Central Valley is the location of Greensward Barony)
     “About one Haven mark.”
     “I’d count them in pfennigs, myself. Bandits and gangs of marauders have been pillaging isolated villages and farms for several standard months. Their raids have emboldened them to the point where we’re getting reports of them sacking entire towns. The most we can hope for is to protect the Central Valley and Castell City, maybe help Graysontown and Falkenberg, Hell’s-A-Comin,’ and help some of the smaller towns train their own defensive forces.”

     Cummings sat down before speaking again, straddling the chair with his chin resting on the back. “Al, I don’t want to lose your friendship and respect. I need to know if there’s some kind of way we can work out a trade or swap. The Brigade’s paychests are empty; I need hard currency to pay and supply my troops. In return, I’ll give you five armored cars, three tanks and a full company of militia assigned to protect Whitehall.”
     The Baron shook his head. “Piss on the rest of Haven and I hope the pack of scavengers who call themselves the Planetary Chamber of Deputies drown in it. They bought and paid for their problems. But for an old friend, hell, I’d do anything. In fact, I bet I can make you a better deal than the one you just offered.”

     The Brigadier perked up. This is going far better than I expected; for a minute there, I thought I’d insulted him. “What is it?”
     “First, tell me how many tanks you have left?”
     “Ten. My mechanics think they can cannibalize the rest and come up with two more working tanks. The armored cars are in pretty good shape, though. They make smaller targets, can go faster and use less fuel.”
     “That means you’ve got durasteel to burn, I suppose.” (durasteel is that miracle armor alloy which Haven cannot manufacture)
     “You could say that,” Cummings said, who felt like a traveler who’s already waded halfway across a swamp and knows he won’t get any muckier if he goes the rest of the way.
     “The machine shops and software survived the raid, or so I’ve heard.”
     “You heard correctly,” Cummings replied. “We can make almost anything you want. So—what is it you need?”

     The Baron told him.

     For a moment Cummings wondered if the metaphorical swamp had just turned into quicksand. Then he laughed. “My first thought was, you’d slipped a cog. But now I’m not so sure; you may be crazy like a fox. Okay, I’ll deal. Let’s talk prices and delivery dates.”
     They haggled for twenty minutes or so before coming to an agreement that they could both shake hands on. To commemorate the deal, the Baron poured two large tumblers of Covenant single-malt Scotch.

     “My lord, we have a visitor. Captain Mazurin of the Colonial Militia.”
     (Baron Hamilton) “Send him in.”
     “Yes, sir.”
     The Captain entered, wearing a travel-stained cloak and field-gray uniform. He bowed to the Baron, then took the offered chair. The butler bowed and left the chamber.
     “We have your first shipment, sir,” the Captain announced.
     “Very good, Captain. Shall I give you the first chest (of gold bullion) now or later?”
     “After we’ve unloaded the truck will be fine.”

     “Excellent. If you and your men would like to spend the night, I’ll have the stewards prepare some rooms.”
     The Captain nodded. “That would be most appreciated, Your Lordship. We could use the rest; it took us over a standard week to make the journey.”
     The Baron frowned. At worst, the journey from Fort Fornova, which was just outside Castell City, shouldn’t have taken any longer than four Earth standard days by motor vehicle. “What took so long?”
     The Captain sighed wearily. “The roads aren’t safe anymore—”
     “Not even for armed men?!” John interrupted.
     The Captain shook his head. “No. In many places the roads have fallen into ruin, or there are barricades to stop travelers. We had to fight off a bandit attack today.”

     Matilda gasped.
     The Captain grew more animated, now that he realized an attractive woman about his own age was interested. He told of an early morning ambush that had ended badly for the outlaws when they discovered that this isolated military convoy had an escort of three platoons made up of the Haven Volunteers.
     “Hunting rifles and pistols aren’t much good when they’re up against assault rifles and rocket launchers. I might even have felt sorry for the—for the bandits, if we hadn’t discovered forty-odd women in the camp. Turns out they’d been kidnapping the wives and daughters of the small farmers they’d killed. Excuse me, ma’am,” he finished, nodding to Matilda.
     “You can speak plainly, Captain,” she replied. “I’ve heard worse; it’s these times.”
     “What did you do with these women?” the Baron asked.
     “Some of them were determined to return to whatever was left of their homes, but we brought most of them with us. Couldn’t leave them unprotected—”
     “I understand,” the Baron interrupted. From the exasperated look on his face, the Baron could see that the Captain was at his wit’s end over the women. It was certainly a dilemma that would have taxed even an older and more experienced commander.
     The Baron smiled. “We’ll be happy to take in any of them who would like to stay here at Whitehall. If not, we can arrange transportation to any surviving relatives. Since we have an abundance of single men on the barony, I suspect the ones who stay will find themselves welcome.”

     John followed the Captain and his grandfather out to the courtyard—what his grandfather liked to call the bailey. He wanted to know what the militia was delivering to Whitehall; the Baron had been very hush-hush over the matter. He certainly wasn’t going to waste his breath asking before his grandfather was ready to answer.
     It wasn’t until the militiamen started wrestling heavy crates out of the back of another truck that his question was answered. Captain Mazarin cut one of the crates open and pulled out a Medieval-style armored helmet. John recognized the helm; it was a sallet, a late-Medieval style of helmet introduced when gunpowder was changing the face of battle back on Earth.
     When Mazarin finished unloading the crate, a dozen gleaming helmets stood in a row on the stone pavement. Now John had another question: Has my grandfather lost his blanking mind? Other than a costume ball, what other possible use was there for these out-of-date helmets? He could easily think of a hundred different things that would be more valuable in exchange for their precious grain stocks.

     “Stand back!” Mazarin shouted, as he drew his sidearm and fired point-blank at the nearest helmet.
     Sprooonnngg! The sallet jumped and tottered. John was unable to see where the ricocheting bullet went. He was too busy staring at the helmet, unmarked except for a tiny nick and a smear of lead.
     “That’s our best durasteel alloy, Baron,” Mazarin said proudly. “It will stop anything short of a spent-uranium slug. Of course, a man can still be knocked down or even break something, if he’s hit in a limb. If he’s hit in the head, he’ll still have to worry about a concussion, whiplash or great murdering headaches. But any brains he has will remain in his head where God put them, instead of scattered all over the landscape!”

     The Baron grinned like a proud father.

     Someone else opened another crate and started laying out breastplates. A third crate held steel shoulder pieces—vam-something or other, he couldn’t remember just what they were called (upper cannon of vambrace). He did remember that one wore some kind of padded garment under his armor, an “arming doublet,” he recalled.
     “We had to build them a bit heavier than they did in the Middle Ages,” Mazarin said, “but the armor is ten times as strong. You’re not going to be turning cartwheels in these, but a fit man should still be able to run. We built them in six different sizes, so they’ll fit any average or large man less than thirty kilos overweight.”

     The Baron smiled. “These will do; by damn, more than do!

     Mazarin picked up a durasteel gauntlet, put it on and wiggled his fingers. “We’re also working on closer tolerance with computerized machine tools. We can do things the old Milanese and Nuremburg smiths never dreamed of. Here try this, John.”
     He handed John Hamilton a gauntlet and a pen. Once John got used to the weight, he found that he could actually write with his armored glove on. He scribbled “Long Live the Empire” on a piece of paper, then removed the gauntlet and handed it to his grandfather.

     The Baron cradled it in his arms as if it were a newborn puppy. “Tell Brigadier Cummings he has my undying thanks. He’s done far better with these than what I had expected. Anything I can do to repay him?”
     “You’ve already more than repaid us, sir. The specie (gold bullion) and food you supplied will keep the Volunteers paid and fed; if we can do that we can do a lot of other things. Now that we’re independent, free of the Chamber of Deputies and Castell, we’ve evacuated Fort El Alamein, so we can concentrate our forces at Forts Fornova and Kursk. All our efforts to date would have been wasted, though, if we hadn’t been able to meet our payroll and keep rations coming in.”
     The Baron looked at the grim stone walls around them as if they showed him some other time or place. “I wish I could do more, Captain. Your militia may be the last hope for civilization on Haven. This stuff”—pointing to the armor—“is my insurance. Or the insurance for my grandchildren and their grandchildren and all the grandchildren to come, for God knows how long. If I’m wrong, they’ll pack it away and laugh at me as I used to laugh at the stories of Old Edwin the Hoarder when I was young. But, if I’m right, this may be all that lets my grandchildren have children.”

     The Baron shook his head as if to clear it of cobwebs. “How many did you bring?”
     Mazarin clearly wasn’t the kind of officer to leave details to his NCOs. He started reciting figures without referring to his belt computer. “A hundred and fifty durasteel sets of armor and five hundred cold-rolled steel sets. The cold-rolled steel won’t stop more than pistol slugs and shell or grenade fragments, but I suspect there’ll be enough of those flying around to make them useful.
     The next shipments would include another hundred durasteel sets of armor and a thousand steel sets, as well as fifty durasteel back-and-breast combinations. The final shipment would include fifty more complete durasteel sets of armor, five hundred durasteel helms and eight hundred more back-and-breasts, three hundred of them durasteel.

     “Now, sir,” Mazarin said. “May I ask a question?”
     The Baron nodded.
     “Why so many sets of armor?” He lowered his voice. “As I understand it, you have less than a hundred men of fighting age at Whitehall.”
     The Baron gave him a knowing smile. “We’ll have a lot more shortly, Captain. Once they’re all trained, I intend to build a real curtain wall, with towers, around Whitehall. Trust me, I don’t believe we’ll have any shortage of new recruits, either. Those steel suits are for my neighbors, or at least those neighbors who think they’re worth an alliance with House Hamilton. If we all stand together, shoulder-to-shoulder, we should be able to keep this end of the Central Valley peaceful.”

From RATE OF EXCHANGE by John Carr and Roland Green (1988)
ARENAK

(ed note: "Arenak" is a handwavium metal with an impossible set of features. It has the same refractive index as air so it is totally transparent, and about five hundred times as strong and hard as steel.

Our heroes Richard Seaton and Martin Crain had visited the planet Osnome in the prior novel, and learned marvelous technological secrets. The villian: Marc DuQuesne and his evil side-kick "Baby-Doll" Loring are trying to kill Richard and Martin, securing their monopoly on the technology.)

      (Richard) "Worrying! That bird is simply pulling my cork! I'm so scared he'll get (my wife) Dottie, that I'm running around in circles and biting myself in the small of the back. He's got a hen on, you can bet your shirt on that—what gravels me is he's aiming at the girls, not at us or the job."
     (Martin) "I should say that someone had aimed at you fairly accurately, judging by the number of bullets stopped lately by that arenak armor of yours. I wish that I could take some of the strain, but they are centering all their attacks upon you."
     "Yes—I can't stick my nose outside our yard without somebody throwing lead at it. It's funny, too. You're more important to the power-plant than I am."
     "You should know why. They are not afraid of me. While my spirit is willing enough, it was your skill and rapidity with a pistol that frustrated four attempts at abduction in as many days. It is positively uncanny, the way you explode into action. With all my practice, I didn't even have my pistol out yesterday until it was all over. And besides Prescott's guards, we had four policemen with us—detailed to 'guard' us—because of the number of gunmen you had to kill before that!"
     "It ain't practice so much, Mart—it's a gift. I've always been fast, and I react automatically. You think first, that's why you're slow. Those cops were funny. They didn't know what it was all about until it was all over—all but calling the wagon. That was the worst yet. One of their slugs struck directly in front of my left eye—it was kinda funny, at that, seeing it splash—and I thought I was inside a boiler in a riveting shop when those machine-guns cut loose. It was hectic, all right, while it lasted. But one thing I'll tell the attentive world—we're not doing all the worrying. Very few, if any, of the gangsters they send after us are getting back. Wonder what they think when they shoot at us and we don't drop?

     (Loring) What is that arenak armor they're wearing?"
     (DuQuesne) "Arenak is a synthetic metal, almost perfectly transparent. It has practically the same refractive index as air, therefore it is, to all intents and purposes, invisible. It's about five hundred times as strong as chrome-vanadium steel, and even when you've got it to the yield-point, it doesn't break, but stretches out and snaps back, like rubber, with the strength unimpaired. It's the most wonderful thing I saw on the whole trip. They make complete suits of it. Of course they aren't very comfortable, but since they are only a tenth of an inch they can be worn."
     "And a tenth of an inch of that stuff will stop a steel-nosed machine-gun bullet?"
     "Stop it! A tenth of an inch of arenak is harder to pierce than fifty inches of our hardest, toughest armor steel. A sixteenth-inch armor-piercing projectile couldn't get through it. It's hard to believe, but nevertheless it's a fact. The only way to kill Seaton with a gun would be to use one heavy enough so that the shock of the impact would kill him—and it wouldn't surprise me a bit if he had his armor anchored with an attractor (Star Trek rename these "tractor beams") against that very contingency. Even if he hasn't, you can imagine the chance of getting action against him with a gun of that size."
     "Yes, I've heard that he is fast."
     "That doesn't tell half of it. You know that I'm handy with a gun myself?"
     "You're faster than I am, and that's saying something. You're chain lightning."
     "Well, Seaton is at least that much faster than I am. You've never seen him work—I have. On that Osnomian dock he shot twice before I started, and shot twice to my once from then on. I must have been shooting a quarter of a second after he had his side all cleaned up. To make it worse I missed once with my left hand—he didn't. There's absolutely no use tackling Richard Seaton without an Osnomian ray-generator or something better; but, as you know, Brookings always has been and always will be a fool. He won't believe anything new until after he has actually been shown. Well, I imagine he will be shown plenty by this evening."
     "Well, I'll never tackle him with heat. How does he get that way?"
     "He's naturally fast, and has practiced sleight-of-hand work ever since he was a kid. He's one of the best amateur magicians in the country, and I will say that his ability along that line has come in handy for him more than once."

From SKYLARK THREE by E. E. "Doc" Smith (1930)

Personal Force Field

FOUNDATION PERSONAL SHIELD

      The trader glanced humorously at the two flabby hands that had been named as his possible executioners then and there, and said, "Your Wisdom, you are wrong on three counts. First, I am not a creature of the viceroy come to test your loyalty. Second, my gift is something the Emperor himself in all his splendor does not and will never possess. Third, what I wish in return is very little; a nothing; a mere breath."
     "So you say!" He descended into heavy sarcasm. "Come, what is this imperial donation that your godlike power wishes to bestow upon me? Something the Emperor doesn't have, eh?" He broke into a sharp squawk of derision.
     Mallow rose and pushed the chair aside, "I have waited three days to see you, Your Wisdom, but the display will take only three seconds. If you will just draw that blaster whose butt I see very near your hand—"
     "Eh?"
     "And shoot me, I will be obliged."
     "What?"
     "If I am killed, you can tell the police I tried to bribe you into betraying guild secrets. You'll receive high praise. If I am not killed, you may have my shield."
     For the first time, the tech-man became aware of the dimly-white illumination that hovered closely about his visitor, as though he had been dipped in pearl-dust. His blaster raised to the level and with eyes a-squint in wonder and suspicion, he closed contact.
     The molecules of air caught in the sudden surge of atomic disruption, tore into glowing, burning ions, and marked out the blinding thin line that struck at Mallow's heart — and splashed!
     While Mallow's look of patience never changed, the nuclear forces that tore at him consumed themselves against that fragile, pearly illumination, and crashed back to die in mid-air.
     The tech-man's blaster dropped to the floor with an unnoticed crash.
     Mallow said, "Does the Emperor have a personal force-shield? You can have one."
     The tech-man stuttered, "Are you a tech-man?"
     "No."
     "Then — then where did you get that?"
     "What do you care?" Mallow was coolly contemptuous. "Do you want it?" A thin, knobbed chain fell upon the desk, "There it is."
     The tech-man snatched it up and fingered it nervously, "Is this complete?"
     "Complete."
     "Where's the power?"
     Mallow's finger fell upon the largest knob, dull in its leaden case.
     The tech-man looked up, and his face was congested with blood, "Sir, I am a tech-man, senior grade. I have twenty years behind me as supervisor and I studied under the great Bier at the University of Trantor. If you have the infernal charlatanry to tell me that a small container the size of a — of a walnut, blast it, holds a nuclear generator, I'll have you before the Protector in three seconds."
     "Explain it yourself then, if you can. I say it's complete."
     The tech-man's flush faded slowly as he bound the chain about his waist, and, following Mallow's gesture, pushed the knob. The radiance that surrounded him shone into dim relief. His blaster lifted, then hesitated. Slowly, he adjusted it to an almost burnless minimum.
     And then, convulsively, he closed circuit and the nuclear fire dashed against his hand, harmlessly.
     He whirled, "And what if I shoot you now, and keep the shield."
     "Try!" said Mallow. "Do you think I gave you my only sample?" And he, too, was solidly incased in light.
     The tech-man giggled nervously. The blaster clattered onto the desk. He said, "And what is this mere nothing, this breath, that you wish in return?"
     "I want to see your generators."
     "You realize that that is forbidden. It would mean ejection into space for both of us—"
     "I don't want to touch them or have anything to do with them. I want to see them — from a distance."
     "If not?"
     "If not, you have your shield, but I have other things. For one thing, a blaster especially designed to pierce that shield."

     "The manufacturers, the factory owners, the industrialists of Korell. When two years of the stalemate have gone, the machines in the factories will, one by one, begin to fail. Those industries which we have changed from first to last with our new nuclear gadgets will find themselves very suddenly ruined. The heavy industries will find themselves, en masse and at a stroke, the owners of nothing but scrap machinery that won't work."
     "The factories ran well enough before you came there, Mallow."
     "Yes, Sutt, so they did — at about one-twentieth the profits, even if you leave out of consideration the cost of reconversion to the original pre-nuclear state. With the industrialist and financier and the average man all against him, how long will the Commdor hold out?"
     "As long as he pleases, as soon as it occurs to him to get new nuclear generators from the Empire."
     And Mallow laughed joyously, "You've missed, Sutt, missed as badly as the Commdor himself. You've missed everything, and understood nothing. Look, man, the Empire can replace nothing. The Empire has always been a realm of colossal resources. They've calculated everything in planets, in stellar systems, in whole sectors of the Galaxy. Their generators are gigantic because they thought in gigantic fashion.
     "But we,—we, our little Foundation, our single world almost without metallic resources,—have had to work with brute economy. Our generators have had to be the size of our thumb, because it was all the metal we could afford. We had to develop new techniques and new methods,—techniques and methods the Empire can't follow because they have degenerated past the stage where they can make any really vital scientific advance.
     "With all their nuclear shields, large enough to protect a ship, a city, an entire world; they could never build one to protect a single man. To supply light and heat to a city, they have motors six stories high,—I saw them—where ours could fit into this room. And when I told one of their nuclear specialists that a lead container the size of a walnut contained a nuclear generator, he almost choked with indignation on the spot.
     "Why, they don't even understand their own colossi any longer. The machines work from generation to generation automatically, and the caretakers are a hereditary caste who would be helpless if a single D-tube in all that vast structure burnt out.

From THE BIG AND THE LITTLE by Isaac Asimov (1944)
HALO

(ed note: The intrepid Curt Newton — Captain Future — has been captured by the evil minions of The Wrecker. The minion's space ship is passing near the Sun on its course to the Wrecker's secret lair. Curt manages to overcome the guard, sneaks out of his cell and into the televisor room. There he quickly contacts his team The Futuremen. But he must leave the ship before his escape is discovered.)

      “No time to talk — come at once! " Curt ordered. and snapped off the wave.
     Then he tore away the whole front panel of the televisor. His deft hands. working against time, unfastened two small transformers, a condenser. and a little auxiliary atomic power generator, that he fastened together into a compact mechanism. Finally he finished hooking together his improvised machine.
     Slinglng it over his shoulder. Curt re-entered the corridor and hastened along it to the mid-ship airlock by which the ship was entered or left. In the inner chamber of the airlock, space-suits were hanging as usual. In a moment. Captain Future was inside a suit. The mechanism he had improvised. he kept slung over his shoulder, outside the suit. Then he opened the outer door of the lock. The air of the lock puffed out. Curt leaped out with it. jumping forth with all his strength so as to escape from the gravitational attraction of the ship.
     The red-headed adventurer leaped out into an inferno of raging light and heat — into a hell of radiation flooding from the sun whose orb jammed the firmament. But as he leaped, Captain Future switched on his makeshift mechanism. Its generator and transformers began humming. It projected a spherical shell of blue light that completely enclosed Curt as he flew out into space — a "halo" or vibration-screen that would protect him from the solar radiation which otherwise would kill him instantly!
     Curt found himself floating in space. The raider ship was receding, a black mass surrounded by the blue flicker of its own halo. Then the ship was gone, his escape unsuspected as yet. And Captain Future, inside his space-suit and protected only by the fragile “halo” from the withering radiation, floated alone in space, only a few million miles out from the sun.
     “It's going to be cursed close." Curt muttered to himself. “If the Futuremen don't hurry —"
     His position was a truly appalling one. For though he seemed floating in space. Curt knew that he was really falling at ever increasing speed toward the sun.
     The gigantic gravitational grip of the stupendous flaming orb was pulling him toward fiery death, by a speed that accelerated each minute. It would take but a few hours for him to fall right into the outer layers of the chromosphere. Could the Futuremen reach him in time, even in the super-swift Comet?
     “It's a gamble. " Curt thought grimly. "And not the first one I've taken — but one of the biggest!"
     Even through the filter-glassite helmet, the glare of the sun was overwhelming. He seemed suspended above a titanic ocean of raving flame that filled the whole Universe. Soon heat began to invade Curt's suit. Curt turned the generator up to higher power, increasing the intensity of the “halo. "
     “Generator can't last long at this rate." Curt thought.
     Before long, he had to turn it up again. And now the generator was beginning to falter, its small charge of atomic fuel depleted by the extraordinary demands made upon it to maintain the fragile screen of vibrations.
     Captain Future felt a queer chill, despite the stifling heat inside his suit. Could this be the end? Had he dared the space gods once too often?
     ‘No. they'll come," Curt muttered doggedly. "The Futuremen won't fail me —
     And as though to confirm his loyalty, the Comet swept out of the upper void like a streak of flashing fire! The teardrop-shaped little ship, the swiftest thing in space, had its shrouding blue "halo" out. It volleyed around in a dizzy turn and drove level beside Curt, its air-lock door open. He clutched, scrambled into the air-lock. In a moment he was inside the little shlp. divesting himself of his smoking hot space-suit in the mid-ship laboratory cabin.

From CAPTAIN FUTURE'S CHALLENGE by Edmond Hamilton (1940)
POTENTIAL BARRIER

“No, weight and spate was what ruled out tobacco,” Koskinen said. “Oxygen was no problem. Not toward the end, at least. With what we’d learned from the Martians—together with them, I should say—we developed an air reclaimer the size of your fist, with capacity enough for two men at top metabolic rate. I’ve included one in the shield unit. Naturally, when I was traveling around on the surface of Mars, using the potential field instead of a thermsuit and helmet…”


"So what is your invisible screen? A potential barrier?"

Surprised, he nodded. "How did you guess?"

"Seemed reasonable. A two-way potential barrier, I suppose, analogous to a mountain ridge between the user and the rest of the world. But I've determined myself, today, that it builds from zero to maximum within the space of a few centimeters. Nothing gets through that hasn't the needful energy, sort of like the escape velocity needed to get off a planet. So a bullet which hits the screen can't get through, and falls to the ground. But what happens to the kinetic energy?"

"The field absorbs it," he said, "and stores it in the power pack from which the field is generated in the first place. If a bullet did travel fast enough to penetrate, it'd get back its speed as it passed through the inner half of the barrier. The field would push it, so to speak, drawing energy from the pack to do so. But penetration velocity for the unit I've got, at its present adjustment, is about fifteen miles per second."

She whistled. "Is that the limit?"

"No. You can push the potential barrier as high as you like, until you even exclude electromagnetic radiation. That would take a much larger energy storage capacity, of course. For a given capacity, such as my unit has, you can expand the surface of the barrier at the price of lowering its height. For instance, you could enclose an entire house in a sphere centered on my unit, but penetration velocity would be correspondingly less—maybe only one mile a second, though I'd have to calculate it out to be certain."

From SHIELD by Poul Anderson (1962)

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