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Post by dragonkid11 on Jan 14, 2017 15:54:14 GMT
Reflective surface is pretty much useless against laser as ANYTHING at all would make it instantaneously weaker.
Like for example as David mentioned, as soon as the reflective surface melts, it will get destroyed by laser immediately.
As to why that happened is simple.
There's nothing in the world that has pure 100% reflectivness.
And since we are dealing with kilowatt and megawatt thermal energy laser here, even just a 0.1% leakage would ruin the reflective surface instantly.
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Post by theholyinquisition on Jan 14, 2017 21:19:44 GMT
The most practical sci-fi laser defense I've seen used gravitational lensing to redirect the light, and I think that's just a bit outside the realm of CoaDE.
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Post by The Astronomer on Jan 15, 2017 5:42:09 GMT
Reflective surface is pretty much useless against laser as ANYTHING at all would make it instantaneously weaker. Like for example as David mentioned, as soon as the reflective surface melts, it will get destroyed by laser immediately. As to why that happened is simple. There's nothing in the world that has pure 100% reflectivness. And since we are dealing with kilowatt and megawatt thermal energy laser here, even just a 0.1% leakage would ruin the reflective surface instantly. China will have a really, really bad time against US laser.
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Post by tukuro on Jan 16, 2017 22:44:30 GMT
Reflective surface is pretty much useless against laser as ANYTHING at all would make it instantaneously weaker. Like for example as David mentioned, as soon as the reflective surface melts, it will get destroyed by laser immediately. As to why that happened is simple. There's nothing in the world that has pure 100% reflectivness. And since we are dealing with kilowatt and megawatt thermal energy laser here, even just a 0.1% leakage would ruin the reflective surface instantly. In itself reflective surfaces and materials aren't that interesting for laser defense due to the mentioned reasons. However, if you can make something similar to silica aerogel out of them(low thermal conductivity), then it becomes interesting. AKA: metallic nanofoams. Sadly I wasn't able to find a lot of info about metallic nanofoams, but I'll keep looking. If you want to get an idea though of how effective they would be: Replace silica aerogel's refractive index with that of aluminium or silver. If you want to read more just follow the link below. The source states that both silver and gold nanofoams have been produced, but I haven't found any conclusive info on them. Yet. www.aerogel.org/?p=932
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Post by lawson on Jan 17, 2017 7:02:03 GMT
The most practical laser armor I can think of consists of a rough ultra low loss fused-silica/diamond/sapphire diffusion layer spaced far enough from an actively cooled mirror wall that even a gigawatt of incoming light can be cooled and dumped into radiators. Note: this armor fails as soon as the attacking laser operates at a wavelength that absorbs in the diffuser layer, or gets focused enough to shatter the diffuser layer. Shattering the diffuser layer takes TW/m^2 and dramatically shortens attacking laser range. Peap-hole turrets then allow kinetic guns to hide behind the armor and arc shots onto target.
Sooty, ablative armor is likely to be moderately effective. I doubt it'll buy more than a few seconds, but also shouldn't instantly fail at some critical intensity. Good for disposable munitions, and as a last line of defense.
Finally liquid metal armor stirred and retained by magneto hydro-dynamic pumps would be my choice for HEAVY armor. (I.e. use as armor Lead Bismuth Tin eutectic alloy, which melts at 95C) As a flowing liquid, it would spread heat well forcing most lasers to boil the whole armor layer. Vs kinetic rounds the density, thickness, and self-healing would make it resistant to all but the most massive shells.
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Post by Enderminion on Jan 18, 2017 14:54:26 GMT
The most practical laser armor I can think of consists of a rough ultra low loss fused-silica/diamond/sapphire diffusion layer spaced far enough from an actively cooled mirror wall that even a gigawatt of incoming light can be cooled and dumped into radiators. Note: this armor fails as soon as the attacking laser operates at a wavelength that absorbs in the diffuser layer, or gets focused enough to shatter the diffuser layer. Shattering the diffuser layer takes TW/m^2 and dramatically shortens attacking laser range. Peap-hole turrets then allow kinetic guns to hide behind the armor and arc shots onto target. Sooty, ablative armor is likely to be moderately effective. I doubt it'll buy more than a few seconds, but also shouldn't instantly fail at some critical intensity. Good for disposable munitions, and as a last line of defense. Finally liquid metal armor stirred and retained by magneto hydro-dynamic pumps would be my choice for HEAVY armor. (I.e. use as armor Lead Bismuth Tin eutectic alloy, which melts at 95C) As a flowing liquid, it would spread heat well forcing most lasers to boil the whole armor layer. Vs kinetic rounds the density, thickness, and self-healing would make it resistant to all but the most massive shells. that liquid armour thing is pretty smart, I would not have thought of it
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Post by The Astronomer on Jan 18, 2017 23:18:01 GMT
The most practical laser armor I can think of consists of a rough ultra low loss fused-silica/diamond/sapphire diffusion layer spaced far enough from an actively cooled mirror wall that even a gigawatt of incoming light can be cooled and dumped into radiators. Note: this armor fails as soon as the attacking laser operates at a wavelength that absorbs in the diffuser layer, or gets focused enough to shatter the diffuser layer. Shattering the diffuser layer takes TW/m^2 and dramatically shortens attacking laser range. Peap-hole turrets then allow kinetic guns to hide behind the armor and arc shots onto target. Sooty, ablative armor is likely to be moderately effective. I doubt it'll buy more than a few seconds, but also shouldn't instantly fail at some critical intensity. Good for disposable munitions, and as a last line of defense. Finally liquid metal armor stirred and retained by magneto hydro-dynamic pumps would be my choice for HEAVY armor. (I.e. use as armor Lead Bismuth Tin eutectic alloy, which melts at 95C) As a flowing liquid, it would spread heat well forcing most lasers to boil the whole armor layer. Vs kinetic rounds the density, thickness, and self-healing would make it resistant to all but the most massive shells. Is it prone to water hammer effect?
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Post by coaxjack on Jan 19, 2017 0:24:22 GMT
I think with the molten composition being as heavy as it is, anything that could produce a damaging fluid hammer would have enough energy to pierce the whole armor layer anyway.
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Post by theholyinquisition on Jan 19, 2017 16:42:00 GMT
There's a bunch of meta-materials that are supposed to be able to bend light. en.wikipedia.org/wiki/Metamaterial_cloaking Would that be a relevant (although frequency-limited, especially with the move towards UV) laser-defense material?
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Post by RiftandRend on Jan 20, 2017 0:53:31 GMT
The most practical laser armor I can think of consists of a rough ultra low loss fused-silica/diamond/sapphire diffusion layer spaced far enough from an actively cooled mirror wall that even a gigawatt of incoming light can be cooled and dumped into radiators. Note: this armor fails as soon as the attacking laser operates at a wavelength that absorbs in the diffuser layer, or gets focused enough to shatter the diffuser layer. Shattering the diffuser layer takes TW/m^2 and dramatically shortens attacking laser range. Peap-hole turrets then allow kinetic guns to hide behind the armor and arc shots onto target. Sooty, ablative armor is likely to be moderately effective. I doubt it'll buy more than a few seconds, but also shouldn't instantly fail at some critical intensity. Good for disposable munitions, and as a last line of defense. Finally liquid metal armor stirred and retained by magneto hydro-dynamic pumps would be my choice for HEAVY armor. (I.e. use as armor Lead Bismuth Tin eutectic alloy, which melts at 95C) As a flowing liquid, it would spread heat well forcing most lasers to boil the whole armor layer. Vs kinetic rounds the density, thickness, and self-healing would make it resistant to all but the most massive shells. What would you do about radiators? They would have to protrude beyond the armor layer and would be quite vulnerable. Superheavy armor seems like a waste if they can just target your radiators.
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Post by lawson on Jan 20, 2017 11:39:22 GMT
What would you do about radiators? They would have to protrude beyond the armor layer and would be quite vulnerable. Superheavy armor seems like a waste if they can just target your radiators. Radiators would either be mounted in the shadow of the laser armor, or kept paper thin and aligned edge on to any laser fire. I've found that radiators hold up under laser fire pretty well if they're made with high temperature materials, especially when edge on the the laser.
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Post by michalo on Jan 20, 2017 16:15:01 GMT
I have another idea about armoring against lasers, which could probably deal with high intensity lasers by scattering the beam. We would have a sort of anti-laser 'whipple shield' - very porous foam made of glass, which should be able to rapidly scatter the beam without getting heated by it. If it works at intended, it will divide the beam power by two (because only half hits the ship, the rest escapes into space) and change it into a very bright lightbulb, which can be placed ten meters from armour, so it could possibly reduce intensity by a factor of 100-1000000.
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Post by Enderminion on Jan 20, 2017 17:39:39 GMT
I have another idea about armoring against lasers, which could probably deal with high intensity lasers by scattering the beam. We would have a sort of anti-laser 'whipple shield' - very porous foam made of glass, which should be able to rapidly scatter the beam without getting heated by it. If it works at intended, it will divide the beam power by two (because only half hits the ship, the rest escapes into space) and change it into a very bright lightbulb, which can be placed ten meters from armour, so it could possibly reduce intensity by a factor of 100-1000000. as before, not perfect
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Post by RiftandRend on Jan 20, 2017 23:08:09 GMT
What would you do about radiators? They would have to protrude beyond the armor layer and would be quite vulnerable. Superheavy armor seems like a waste if they can just target your radiators. Radiators would either be mounted in the shadow of the laser armor, or kept paper thin and aligned edge on to any laser fire. I've found that radiators hold up under laser fire pretty well if they're made with high temperature materials, especially when edge on the the laser. Wouldn't shockwaves traveling through the fluid armor snap off thin radiators?
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Post by lawson on Jan 21, 2017 2:24:30 GMT
Wouldn't shockwaves traveling through the fluid armor snap off thin radiators? Yes shockwaves in fluid armor could cause problems for thin radiators. Note: due to weight, fluid armor would likely only be employed in "orbital space forts" or certain MPD ships where the armor layer is also reaction mass. So on nearly immobile objects you could flex mount the radiators, or use a heavily armored first segment. Also any radiators exposed to direct attack would generally be retracted below the liquid armor layer. Finally splashing is likely to be a FAR greater problem for liquid armor. Though I think splashing could be managed via an array of small electron guns that would charge up any droplets before they could escape. Fyi, I first saw liquid armor used on Iserlohn Fortress. Probably not the first appearance of liquid metal armor, but one of the most impressive!
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