Ever notice just how ridiculously worthless the Star Wars stormtroopers are? I mean, for the fear-inspiring, rebel-slaughtering shock troops of the Galactic Empire, they sure do go down real easy when anybody shoots them — anywhere.
So, what's the issue? Are they simply all hemophiliacs? Are they suicidal? I think it's more likely that the Empire, concerned with balancing the budget, has skimped on its troopers' armor. I'm pretty sure if we were to clothe the troopers in anything else — ANYTHING else — they'd probably do better out there. After all, how hard can it be to stop a little ray of light?
Really effin' tough, actually. Last December, the U.S. Navy developed an injector capable of producing the electrons needed to generate megawatt-class laser beams. That's enough energy to power a Eurostar locomotive at top speed! So what's a casualty-weary empire to do? Let's put 10 different modern materials to the test.
1. Conventional Steel
Military-grade steel can handle temperatures exceeding 2,500 °F before melting. The hottest combat-ready laser beam itself is "only" about 1,832 °F. Not too shabby, right?
The problem is that steel also conducts heat fairly readily, so you'd be cooked way before your armor is. Factories all over the world are already using cutting lasers to machine steel, anyway. Plus, the lasers we're talking about will be designed to eat through conventional armor like this.
It works for bullets, right? Kevlar is actually a big improvement on steel as far as heat is concerned. With a melting point of 932 °F, Kevlar would seem the weaker substance, but because the carbon in Kevlar is unsaturated, it's more stable and therefore harder to burn. It is this heat-and-fire retardant property that makes Kevlar the choice for fire departments worldwide.
The problem with Kevlar is that the higher temperature it reaches, the faster it breaks down. For instance, at 320 °F there's about a 10% reduction in strength after 500 hours at that heat. At 500 °F, though, there's 50% reduction in strength after 70 hours. That's both a greater weakening and in a shorter period. So while it's great for short periods under the laser, a more extended exposure at 1,000 °F or so would start to break down individual fibers, creating holes that would let portions of the laser light through.
Not a huge improvement over the ol' one-shot-dead stormtroopers, as it turns out.
3. Pretty Colors!
Welcome to the Crayola approach: one funny thing about lasers is that they are monochromatic. They have to be to line up their photons and travel in organized wavelengths. What's that mean? A redshirt would last a lot longer in Star Wars than he would in Star Trek.
Any object of the same color of the laser being pointed at it, thanks to the reflective property of light, would only hold onto the laser's energy for an instant and would then reflect it away. Something as simple as a cotton blanket of the right color can deflect a tank-destroying multi-megajoule laser.
The problem? The color match has to be exact for this to work. It also isn't a permanent solution. Like the Kevlar, some of the energy of the laser is going to build up in the fabric, eventually tanning or burning it, altering the color. The second the color is changed even minutely, the armor is rendered predominantly useless.
4. Gels And Liquid
There are two takes on gel armors out there. The first is called "ablative armor," which is an array of tightly-clustered gel or foam packs. The laser, when hitting this, is going to rupture the gel packs that it strikes, saving your boys from the first hit. The second shot — or a prolonged one — will go right through, however.
Second, we have liquid armor, developed at Aberdeen proving ground in Maryland for the U.S. armed forces (pictured above). It's actually less liquid than it is ablative armor — a hybrid compound of solid silica particles and a sheer thickening fluid. The mix creates a reactive substance that stiffens when assaulted by particles. A thick fluid might dissolve slower when hit by photons and heat, but also might not react as well as if being struck by blunt force.
Another problem might be that, if the armor does react, you'd freeze your troopers in place until the laser was turned away from them. No matter how long it takes the laser to eat through the armor, if your troops aren't moving, they're as good as dead already.
Reflective surfaces bounce light around, right? Mirrors are totally the obvious choice when talking about light, right? Why didn't we think of this before? Well...
Mirrors — believe it or not — are usually frequency-specific; one that reflects visible light might not reflect UV or infrared wavelengths. So they have a better spectrum of protection than our red shirt, but aren't universally protective. Another issue is that most mirrored surfaces are not 100% smooth, meaning that some of the energy from the laser will be absorbed, probably melting or marring the reflective surface.
Bottom line: it'll give you a couple direct hits, but after that, your mirror is likely damaged and useless.
Heat resistant ceramics, including bricks and tiles, are well known for their ability to withstand high temperatures. Advanced ceramics used in military armors are more heat resistant than these materials by far. While aluminum begins to melt at approximately 1,220 °F, an advanced ceramic called alumina only begins to melt or decompose at temperatures above 3,632 °F. Even more impressive is zirconia, with a coefficient of thermal 1/10 that of stainless steel. That's tough stuff!
On the other hand, the instability of zirconia is a big and not well understood problem. Ceramic made out of the strong tetragonal crystals may spontaneously transform into other crystalloid forms. The ceramic consisting of these other crystalloid form is weak, rough and fragile. So, we'd have freak accidents with this stuff, but would "often" be safe.
Crystals are used in the production of laser light, so why not utilize them in the refraction of it? The crystals that are implemented in lasers are harmonically designed to align wavelengths of light.
The book Atomic Physics by Max Born tells us that natural crystals are set up in anharmonic terms, meaning that they reflect and disperse heat energy to zero fairly rapidly. This would seem ideal for armoring a bunch of dudes, but if heat were allowed to pass through the crystal due to some random harmonic alignment inherent of the crystal, the heat would be conducted easily through the barrier, potentially even magnified.
There are limits to crystals as well. The net ability of a crystal to scatter heat is directly related to it's size. The larger crystals in weapons might be able to overpower the smaller ones incorporated in your armor. Constant temperature could also effect the crystal, eventually breaking it down.
8. Reflective Dust
Stepping outside the box, one effective defense against lasers would be aerosol cans. The canisters would pump reflective ultrafine particles into the air around you. The particles would be fine enough to hang suspended in the air from several minutes to up to half an hour, depending on weather and wind conditions. A laser beam hitting these particles would disperse just as if it had hit a thick dust cloud, even though to the naked eye the area would appear only mildly hazy.
Like the mirrors mentioned earlier though, the reflective properties of the aerosol particles may only work against certain wavelengths. And then there's the question of what you do when you run out of defensive dust cans, or if there's a breeze.
9. Composite Materials
Back in March of last year, DVICE walked you through the protective properties of bomb-proof suits. Taking a similar approach here seems like our best chance at conventionally armoring an individual to withstand laser-fire. Implementing thin, crystal-lined zirconia plating in a gel matrix would allow ample dispersion of heat and the refraction of a laser's wavelength while maintaining a fail-safe under-layer as well. It stands to reason that a suit of laser-proof armor in the future will be a mishmash of composite material that incorporates these attributes, if not these exact ingredients. So, what's next?
10. Personal Shield Generators
Remember a little while ago when the world's first anti-laser showed up in the news? Well, the concept of utilizing such a device for personal protection isn't that far-fetched, really. The "coherent perfect absorber" (or CPA) developed at Yale currently absorbs specific infrared light. Its developers are sure, however, that the CPA will be able to absorb visible light as well. For our purposes it could someday be the adjustable, reusable laser defense system we've been looking for — ideally by the time my own legion of stormtroopers is cloned up.
Now where did I leave that recruitment flier?