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In most future sci-fi settings, it is apparent that laser weapons (or as Star Wars likes to call it, blasters) and energy weapons in general would have replaced most standard ballistics for main infantry to use.

With that in mind, armour made to deal with physical weapons such as knives or guns would most likely no longer be necessary, and new armour would be made to instead deal with energy weapons as such.

I know that the ideal materials for such armour would be those that are heat-reflective, bear high melting points (for more powerful plasma / laser weapons), and radiation-reflective.

Notably, I especially want to have materials which are the best of their caliber, such as the most reflective material, or the material hardest to burn.

Thus, I ask, what ideal combination of materials could be used to form such an armour. Any material is fine, as long as no major unobtainium is involved.

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    $\begingroup$ Laser, plasma and particle beams have different ways of interacting with matter, and therefore different countermeasures. You are asking 3 different questions $\endgroup$
    – L.Dutch
    Jan 26, 2020 at 7:28
  • $\begingroup$ Okay, took out plasma. $\endgroup$ Jan 26, 2020 at 8:17
  • $\begingroup$ @L.Dutch-ReinstateMonica And if you wanted my honest opinion, they really are the same when you think about it. All transfer thermal energy and radiation. What works for one is more or less similar to the other. $\endgroup$ Jan 26, 2020 at 8:24
  • $\begingroup$ for one, make sure that the armor is also a Faraday cage to avoid lightning-like weapons. thinking that you aren't required to defend against knives is a bit naive, in any sort of urban/ship warfare there will be melee combat, just imagine having to fight through a stacked cargo hold with plenty of nooks for some one to just at you with what ever high-tech monomulecular blade. also a good thing to note is that if everyone has effective energy weapon resistant armor, people will switch back to slug throwers so you really gotta defend against both $\endgroup$
    – Nullman
    Jan 26, 2020 at 8:53
  • $\begingroup$ Laser comes in different frequency/energy and so a perfect dielectric stack mirror better than those in the market and maybe just carry around big electromagnet to counter plasma. $\endgroup$
    – user6760
    Jan 26, 2020 at 10:35

2 Answers 2

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Important note to start: when I'm talking about laser weapons, I'm referring to the things that Luke Campbell refers to as Blasters, high power, very short pulse length, drills through target in a series of pulses. If your laser can't do this, it probably isn't very good as a weapon, so I won't consider it. I'll also not consider x-ray lasers, because they a) don't work well in an atmosphere and b) will absolutely ruin your day in space, regardless of armour, so they're not interesting to talk about here.


Here's the main thing to remember. A laser powerful enough to be a useful weapon can't be stopped by reflective armour, or heat sinking, unless you are using magical handwavium for one or the other. A wonderfully super reflective surface will only be super reflective for a brief instant... it will still absorb enough energy to ruin its reflectivity, and then it is useless. Furthermore, the highest levels of reflectivity tend to be against very specific frequencies, and a slightly different colour laser will be barely effective. So forget mirrors.

Also forget ablative materials. Against a serious laser, all armour is ablative armour, so you may as well use something that's actually useful as armour, under the assumption that other weapons and enivronmental hazards still exist. The stuff you paint re-entry capsules with is really not robust enough for that purpose.

There's a possibility that smoke-generating reactive armour might save your buddies, but there's a good chance that the laser pulse train that triggered it can still kill or cripple you (and a short enough laser pulse can drill without heating, and so could perforate you without activating your defenses at all). That means in a carefully planned ambush, if you're relying on reactive armour, everyone can be killed before the cloud of crud can obscure you. So don't rely on that, either. You also don't want to risk your own defenses being turned against you by low-power devices that turn you into a smokescreen with legs, leaving you blinded and disoriented! Smoke can help in an atmosphere (see atmospheric breakdown below) but it is pointless in a vacuum; no more useful than the same mass of proper armour and probably worse. So don't bother with reactive stuff, either.


First job, then, is to make your armour out of something that is highly refractory. The point at which the beam touches the armour will be flashed to plasma and there's not a whole lot you can do about that, but the armour around it will be melted or boiled, and the force of the expanding gas and plasma will blow the melted armour out of the hole. A material that can absorb lots of energy before melting means that the region of vapourisation and melting around the laser strike point will be as small as possible and grow as slowly as possible.

Second job is to make your armour out of something which is tough. Where a laser pulse lands upon armour, it will cause vapourisation and that vapour cloud will expand rapidly: an explosion, though only a little one. That will cause mechanical damage to the armour, causing it to crack and disintegrate. Tough armour that can absorb a lot of punishment and remain intact is the order of the day, as that keeps the hole drilled by a laser narrow, and the rate at which it gets deeper will be slower.

What you need, then, is a nice carbon nanotube weave. Carbon has a very high melting point, and nanotubes are very tough. Diamond, and refractory diamond-like materials such as sapphire may work, but whilst very hard lack the toughness of woven materials and so would need to be made as composites to stop cracks propagating. Boron nitride nanotubes may be even better than carbon ones. Lasers can and will cut though these materials, but against a target wearing this sort of armour the lasers will have to be higher power, and more tightly focussed, or used at shorter range.

In an atmosphere, those three things risk atmospheric breakdown where the atmosphere itself absorbs enough energy from the laser beam to turn into plasma, and that plasma will be opaque to the laser beam. When the air starts breaking down, laser weapons will become much, much less useful. You can therefore combine your fancy nanoweave armour with simple smoke grenades that fill the air with fine particulates to enhance breakdown effects, which can render you effectively impervious to man-portable lasers at sensible ranges. On the flipside, it also means you can't use lasers, visible light sensors (such as eyes) and laser-based point defense systems will become useless, so now you're vulnerable to kinetic and explosive projectiles instead. Happily, unlike silly heatsinking reflective armour, your nanoweave plating isn't that bad at keeping other kinds of badness out either.

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Perhaps a reactive amour over a base of highly reflective armour might work. Something that will react vigorously when exposed to high intensity laser radiation to form a cloud of laser reflecting micro particles. Something with a fine cellular nature that would help direct the ejected material back towards the beam rather than sideways.

After initial the initial exposure a small cloud of particles would form helping to block, deflect and dilute the beam. The more energy that got through the more particles would be released (to a point) and th base layer would have to deal with anything that got through.

Hexachloroethane-zinc and aluminium as used in white smoke grenades might be suitable. A tiny pellet of hexachloroethane-zinc could be covered in a thin layer of protective plastic film and then coated with a layer of resin containing a high concentration of powdered aluminium. This material could then be incorporated into the outer layer of the armour.

An incoming beam would quickly rupture many of these tiny pellets bringing the reactants into contact and causing the formation of a small dense cloud of smoke at the point of impact reflecting and attenuating the incoming beam.

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  • $\begingroup$ This reactive armour... do you mean the ablative layers used in spacecraft during reentry? $\endgroup$ Jan 26, 2020 at 13:09
  • $\begingroup$ I was thinking more of the smoke you would get from a grenade. I have updated my answer to include this. But your idea might also work or both might work together $\endgroup$
    – Slarty
    Jan 26, 2020 at 14:47
  • $\begingroup$ The best bit about this idea is the way that anything that produces a relatively low power laser beam or shower of sparks can cause a target to be engulfed in a cloud of its own thick, impenetrable smoke. It'd almost be slapstick, with your peeps blundering around huffing out clouds of the stuff and unable to see where they are or what's going on, right up to the point where they all got blown up by more conventional weaponry that they couldn't see, couldn't evade and couldn't intercept. $\endgroup$ Jan 27, 2020 at 15:03
  • $\begingroup$ Well you could ajust the thickness and the coatings so that only a very powerful laser would trigger it otherwise it would be pointless wouldn't it as you describe. Mind you conventional weaponary would always be an issue $\endgroup$
    – Slarty
    Jan 27, 2020 at 15:56

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