JOHT 5: Powered Armor

[stickmaker]

I have caught up, so am now working on posting some of the older ones. 

The Joy of High Tech

by

Rodford E. Smith

Being the occasionally interesting ramblings of a major-league technophile.

Please note that while I am an engineer (BSCE) and do my research, I am not a professional in this field. Do not take anything here as gospel; check the facts I give. And if you find a mistake, please let me know about it.

Powered Armor

Powered armor of various types is very popular in science fiction. The concept has been around in print SF since at least the Thirties and stories featuring it are still being written. One medium which has made extensive use of powered suits of armor and similar equipment is Anime, or Japanese animation, where powered armor suits and giant robots have been reached the point of ridiculousness and gone well beyond. This article is intended as an overview of the technology behind the man-sized suits of powered armor.

First, let's make sure that we are all talking about the same thing. You can assign all articulated combat devices to one of three classes: automatons, suits, or vehicles. In fiction, the automatons range in size from dolls up to at least such large pieces of equipment as the classic giant robot. They may be completely controlled from a distance, or possess various degrees of autonomy, all the way to true robots, capable of making their own decisions about complicated situations. Suits are meant to be worn, and for humans range in size from a meter and a half to about three meters. Anything with someone inside which is larger than this is a vehicle. It may still be controlled pantographically (by the natural movements of the operator, rather than through joystick, pedals, or keyboard) but the person operating the thing is in a cockpit, piloting a vehicle instead of wearing a suit.

The difference between suits of powered armor and the older, traditional type of protection is that the powered suits carry their own weight, and sometimes more. They also mount or otherwise allow the use of heavier weapons than the operator could carry without the armor. As usual, SF anticipated a real-world situation by several decades. The US Army is currently (as this was written) working on at least one such piece of equipment, the SIPE. This stands for "Soldier, Integrated Protective Ensemble." This will not only provide protection from small arms fire and explosive debris but also carry its own weight and more and house communications and sensor gear, as well as provide full ABC (Atomic, Biological, and Chemical) protection. There is probably other such equipment under development, both in the US and elsewhere.

The SIPE is not intended for "hand-to-hand" combat, and there is no provision for strength "amplification." It is primarily a one-person armored personnel carrier, keeping the burden of its own weight and of the equipment carried off the back and legs of the operator. The SIPE - at least in the version I have read about - is a mixture of hard and soft armor supported by an exoskeleton. Technical details are still classified, and are probably still being researched. Even this admittedly crude device would have communications and sensor gear more sophisticated than what is used in most suits from fiction. Power would come from a small internal combustion engine in the backpack, probably a Wankel rotary. At our current level of technology this is about as good as we can do for power, and for the intended function of the SIPE it is quite adequate.

Okay, so let's build a suit of armor using next generation systems, which will result from technological developments which can be realistically expected in the near future. Along the way, I'll compare this with what is available now.

 Armor: There are several approaches to this. Currently, the best we can do for a true "hard shell" suit of armor would be a laminate of titanium and graphite/epoxy composite, with maybe some boron fiber composite included. Faceplates would also be multi-layered, with an outer surface made from something like the ceramic glass or metallic glass, backed by polycarbonate and with polarizing material and anti-fogging heating elements incorporated. In the near future we can expect to be able to use things now known to exist but available only in small quantities for use in laboratories. This includes mono-crystalline iron filaments, which have an incredible tensile strength. Even better, though, would be perfect diamond whiskers, embedded in an advanced epoxy bonding agent. This would produce a lightweight, inexpensive composite with strength and resilience even greater than that provided by mono-crystalline iron. Unlike solid metal armors, composite materials retain a large percentage of their strength after initial failure, so even if a suit was damaged it would still protect the wearer from most threats.

"Inexpensive?!" you cry. "We're talking about diamond!" Well, not really. This isn't a matter of making large gems. What this entails is extruding graphite fibers under conditions of heat and pressure that cause the carbon to assume the same atomic bonding that is found in diamonds. 

Vapor Phase Deposition of diamond onto fibers is also a possibility. In case you doubt the feasibility of this, one Japanese company is already offering surgical instruments with a bonded diamond coating. These coatings are more chemically stable than stainless steel, and able to take a remarkable edge. This same process, on a larger scale, would allow a diamond coating to be added to the suit visor.

Somewhat beyond what can be reasonably forecast are materials made from rings or spheres of carbon. Buckytube (carbon nanotube) materials would be at least an order of magnitude stronger in tension than perfect diamond whiskers and both more chemically stable and more flexible. More theoretically, solids made from interlocking, benzine-like rings of carbon atoms in a three-dimensional matrix would be fantastically strong. Suit armor made from such materials would protect the wearer from anything short of an anti-tank weapon. Even then, more danger would come from the shock of impact rather than from penetration.

Strength Amplification: This would more reasonably be called strength augmentation. The control system would measure and compare the exertion of the wearer to the resistance being experienced, and boost the force until the object moves or the suit reaches its limit. The actuators could be of several types. Currently, the best bet would be a combination of hydraulic pistons and turbines, and electric motors. However, you couldn't say that the resulting motions accurately mimic those of a living creature. Hydraulic systems would give great strength, but are bulky and just don't work as smoothly or quickly as muscle, and in a suit you want natural movement. To provide this, you need something that operates in much the same manner as the muscles themselves. A crude version of this already exists: fibers which contract when electric current is applied to them. A more advanced electroelastic fiber would be ideal for a suit of powered armor. These could be aligned to mimic the natural pattern of muscle fibers, easing control problems.

Controlling Movement: Candidates for control systems in a current technology suit could include myoelectric sensors; piezoelectric force detectors and other pressure sensors; and fluidic position sensors and repeaters which operate in much the same way as the power steering in a car. The best bet would be the myoelectric sensors, which detect the signals nerves send to muscles. They are small, simple, and relatively inexpensive. Even better would be a combination of two or more of the systems listed, for greater flexibility of response and operational redundancy.

Near-term future development should be able to provide a system which is far better than any of these. A SQUID (Superconducting QUantum Interference Device) array detects the minute magnetic fields produced by brain activity. They're a non-invasive method of monitoring brain activity in detail. Units now available fill a small room and have moderately good resolution of only one small area of the brain at a time. If this technology advances only as rapidly as microcomputers have in the past twenty years, then by 2040 a unit which can monitor the entire motor and speech areas of the brain will fit in an oversized helmet. The suit would literally read its operator's mind - or at least the brain - moving as they move and accepting subvocalized instructions, a concept dating back to at least 1985. Once the neural net computer in the control system is taught how to correlate between the brain's signals and the body's physical movement, controlling the suit would be as natural as operation of the wearer's own limbs.

Sensor Gear: Current sensors come in various types. Electromagnetic sensors range from visual, through near-visual (IR and UV) to radio frequency (radio and radar). Sound sensors are available in both active (sonar) and passive (selective amplification and pattern matching) types. For the near future, we can expect mostly just refinements of these systems, though magnetometers and such might be added. Some sort of tactile repeater (generally referred to as haptic) for the hands and feet would also be very useful. Phased array radar can be fitted into the helmet, providing a rapid-scan, multi-frequency radar capability. Seismic sensors could detect movement of heavy objects (such as enemy armor) nearby, and even provide some indication of direction. Atmospheric analyzers could provide information on exhaust fumes and outgassing of various materials, perhaps even allowing identification of individuals by scent!

Information Overload: The problems involved with

presenting the accumulated data in a way that doesn't

overwhelm the operator is very important. However, discussion of this highly technical subject would bore most readers, so let's just say that the HUD (Heads Up Display) technology used in modern military aircraft is already more advanced than most of what is shown in fiction. Of course, this could simply be due to writers of these stories wanting to avoid losing their audience as much as I do.

Power Source: The energy to operate the suit must come from somewhere. Above I mentioned a small rotary engine. Other power sources now available include exotic, high-density batteries, fuel cells, MHD generators and small gas turbines. For the near future there would be improved versions of all these plus the possibility of fission or fusion generators. Such power supplies would require some sort of buffer to take care of short term, high-power demands. The best way to do this would be with a superconducting loop. Currently this requires cooling the loop to liquid nitrogen temperatures, but room temperature superconductors are a few degrees nearer every year.

Even if high-temperature superconductors remain out of reach, very small, high-efficiency cryogenic refrigerators are already almost an off-the-shelf item, since these are used in a number of satellites and space probes. There should be little trouble in making them small and rugged enough to cool a loop of superconducting material to liquid nitrogen temperature.

Getting Around: You can't build armor to withstand every weapon, not even for a main battle tank. Mobility is therefore important. With the control and actuation systems which should be available within twenty years, the operator would be able to run at least as fast in the suit as when out of it, and jump farther than normal. This is just the start.

Many of the powered armor suits from fiction have had some means of flight, usually jump jets or rockets. These produce a high thrust for a short duration, allowing the suit to travel tens to hundreds of meters in a very short time, as well as gain a temporary altitude advantage in combat. In some cases true flight is possible. Unfortunately, both rockets and jets produce a significant heat and noise signature, and tend to raise a cloud of dust on takeoff and landing. Also, jets need air to work, and would be useless in a vacuum. If you are willing to accept that limitation, though, there is something much better than either jets or rockets. Ducted fans, driven by electric motors designed to provide high output for short durations, would be nearly ideal. Such a system has a low heat signature, as well as much less noise than from either alternative mentioned above, and even the dust is raised is less, since the downblast is spread over a larger area. This system would require a sizable amount of power in brief pulses, but that could be supplied by one or more superconducting loops, as described above.

Armament: Naturally, powered armor needs weapons.

Lasers are an obvious choice, and with power supplied by the suit there are several off-the-shelf industrial lasers which could be adapted without much trouble. Other current weapons include grenade and rocket launchers, a powerful but otherwise conventional rifle (such as the .50 caliber anti-material rifles already in use) and so on. The near future developments bring improved versions of all these, plus a couple of new devices.

Magnetic accelerators are often used in fiction, but too many people describe them as "railguns." While the railgun (which is not exactly magnetic) is an important research tool, it has to be rebuilt after every few shots, making it impractical as a weapon (though this has improved enough in recent years for a few to be deployed for field tests). Instead, the coilgun - something very much like a solenoid - should be used. The US military has worked on several weapons based on this technology. The great advantage of magnetic accelerators is that they can produce a very high muzzle velocity. Since effectiveness against hard targets is more closely related to kinetic energy than momentum, you want a lightweight projectile moving at high speed. The coilgun can provide it.

Another new weapon is the ramshell launcher. The basic technology is currently under development as a way of sending small payloads high into the atmosphere without the use of a sounding rocket. Essentially, the shell in its smoothbore launcher is an inside-out ramjet. Vaporized fuel (such as butane or methane) is injected into the bore ahead of the projectile. A small propellant charge starts the projectile moving and the flash ignites the fuel as it squeezes past the projectile. The muzzle velocity is about the same as for a low-end coilgun, and the weapon doesn't use any suit power since it is chemically fueled. It is also recoilless. A 40mm version of this, using a tough outer shell with a depleted uranium penetrator, would punch completely through one M1 Abrams from front to rear, and partially through another (assuming the shell held together, which it probably wouldn't). However, the ramshell launcher has an enormous signature, with a fireball erupting from each end. The weapon would also be large - measuring more than two meters long - and mass over seventy kilos, even using advanced materials. Still, with the suit, handling the weapon shouldn't be a problem. Neither should the double blast. The ramshell launcher would provide the operator with the punch of a four-inch naval gun at an effective rate of fire of about one shot per three seconds.

An important force multiplier is making weapons usable automatically by the suit, as well as by the user. Small to medium sized weapons could be placed on a steadymount, similar to the device used for making walking camera shots that don't bounce, attached to the back of the suit at the waistline. By adding actuators at the hinges, you can have the suit's computer direct the weapon(s) so mounted, to act while the human operator is otherwise occupied. This is the sort of innovation that most fictional suits have lacked. Within each suit, the operator would be more like a sergeant directing a squad than a knight in armor.

Impractical Features: Okay, now what are some of the features of fictional powered armor suits that are not practical? High heel boots for one. Anything that transforms, for another. Sorry, but the motorcycles from such Anime shows as Mospeda are just ridiculous. Sure, they look good, but the added weight and complexity required to install the shape-changing function would defeat the purpose they are supposed to serve. Melee weapons, such as swords, axes, and chainsaws (remember the instant convertible from MADOX-01?) are downright ridiculous, except under certain, very unlikely circumstances. (Even Mobile Suit Gundam is guilty here.)

On the Other Hand: Shields are often used with fictional suits, and are actually quite practical for powered armor combat. They allow the operator to add protection with less weight and complexity than is needed to improve the entire suit, and can be discarded quickly in the event that more mobility is needed. A properly designed shield could even be used as a wing, to extend powered jumps.

An implement something like a giant crowbar, or a spud bar would also be handy. It could be used for breaking into areas where use of explosives wouldn't be advised, such as bunkers where there may be hostages. Made of appropriate advanced materials, it would be extremely tough. In the improbable instance of needing a melee weapon, it would serve nicely as a quarterstaff. No energy swords required.

This is just a brief overview. Suits of powered armor are technically practical, or should be within the next twenty years. Let's just hope we don't need them.

My thanks to Dr. John Brantley for telling me about ring carbon armor.

Comments

[kengr]

One factor I keep seeing ignored with regards o powered armor is that there is a major gap in size between the suits and the vehicles.

This is because for a suit, the joints have to *match* the joints of the wearer. That is, the knee has be at the same location as the wearer's knee, ditto for elbows, ankles, shoulders, etc.

This has major effects on the suit's appearance and height.

The height should be obvious. Except for the height added by the soles of the boots, the armor (without helmet) has to be the same height as the wearer.

Since the armor and actuators make the limbs and body thicker this means the armor will *look* short and squat. That's because the distance between bending points will be the same, but everything will be thicker, thus resulting in a much different width to length ratio. Look at the first Iron Man suit in the comics. That one got it mostly right.

This also has major effects on range of motion, as the thickness of the limbs reduces the arc they can move thru before surfaces come in contact (eg calf touching thigh).

I've seen far too much art that has the suits having normal human proportions which just isn't going to happen.

I've also read several descriptions where the authors didn't understand that bit about joint locations. Given the suit dimensions as stated, the wearer would break his arm or leg as soon as he moved it. Oy.

Oh yeah, those range of motion issues mean that the suits are going to have major weak points at places like behind the knees, inside the elbows, and the armpits. Likely in the groin/butt area as well.

You have to have gaps in the armor there or give up major amounts of flexibility.

Oh yeah. Ring carbon sounds great. Just one *tiny* problem that's been overlooked.

The the bounds that make the rings so strong are due to the valence electrons being "smeared" together. Rather than the alternating double and single bonds you see in diagrams, it's more of them all being "one-and-half" bonds.

That quantum smearing means that even if you managed to create interlocking rings, they'd be just as likely to pass thru each other (or to bond in to a new structure that wasn't a pair of rings) as to stay linked. Pity.

TL;DR carbon rings aren't solid. They're a sort of donut shaped cloud.