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Post by Esterov on Jan 10, 2017 1:21:10 GMT
Just throwing the idea out there.
Not really knowing anything about the processes involved, how effective would it be if you vented out CO2 or some other gas in an attempt to block IR lasers?
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Post by David367th on Jan 10, 2017 1:38:59 GMT
I'm thinking the vacuum of space would suck the gas or smoke into such a thin mixture it would be like there was nothing there at all. However in the real world (with atmosphere) there are anti-laser smokes that vehicles use to defend themselves against laser-guided attacks.
Though maybe a gigawatt laser could be powerful enough to damage things on the inside??
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Post by caiaphas on Jan 10, 2017 3:30:48 GMT
My gut tells me it's a hard no, and I'm too tired at the moment to try and run the hard numbers (but if I weren't, the things I would look at would be the Vrms for the gas in question, and the basic assumptions that you're making about how the gas is stored, such as temperature, pressure, and density, basic PV=nRT stuff).
Anyways, calcs aside, the reason I think it'd be a wash is that the basic damaging principle is the same: you're heating molecules to the point of vapor, which then leave the site you're pointing the laser at, gouging a hole. This is naturally going to be easier (i.e. require less energy input) when you're using materials that are already gases at room temperature, as opposed to materials that are solid at room temperature.
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Post by someusername6 on Jan 10, 2017 3:37:00 GMT
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Post by coaxjack on Jan 10, 2017 4:16:24 GMT
I'm thinking the vacuum of space would suck the gas or smoke into such a thin mixture it would be like there was nothing there at all. However in the real world (with atmosphere) there are anti-laser smokes that vehicles use to defend themselves against laser-guided attacks. Though maybe a gigawatt laser could be powerful enough to damage things on the inside?? Specifically the smoke is to break the target lock of a sub-kilowatt designation spot for an incoming guided munition, not to attenuate a multi-megawatt kill laser.
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Post by caiaphas on Jan 10, 2017 4:47:05 GMT
I'm thinking the vacuum of space would suck the gas or smoke into such a thin mixture it would be like there was nothing there at all. However in the real world (with atmosphere) there are anti-laser smokes that vehicles use to defend themselves against laser-guided attacks. Though maybe a gigawatt laser could be powerful enough to damage things on the inside?? Specifically the smoke is to break the target lock of a sub-kilowatt designation spot for an incoming guided munition, not to attenuate a multi-megawatt kill laser. And since our munitions are all thermally guided, that isn't going to do jack to them.
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Post by Enderminion on Jan 10, 2017 15:16:24 GMT
gas no it would fly off into the void in milliseconds, dust particles though that don't fly away... could be useful as active defense vs lasers and cooling gun barrels
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Post by caiaphas on Jan 10, 2017 17:07:03 GMT
gas no it would fly off into the void in milliseconds, dust particles though that don't fly away... could be useful as active defense vs lasers and cooling gun barrels Dust would still be hilariously less effective than an equivalent-mass plate of solid armor (the Atomic Rockets link above covers this very well), and as for cooling, well, you run into the issue of "how much spare space and mass budget do I have for the gas tanks I'll need"?
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Post by Enderminion on Jan 10, 2017 18:14:20 GMT
gas no it would fly off into the void in milliseconds, dust particles though that don't fly away... could be useful as active defense vs lasers and cooling gun barrels Dust would still be hilariously less effective than an equivalent-mass plate of solid armor (the Atomic Rockets link above covers this very well), and as for cooling, well, you run into the issue of "how much spare space and mass budget do I have for the gas tanks I'll need"? big thing is, its not your hull armour and even a few seconds can make a huge difference
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Post by bigbombr on Jan 10, 2017 18:31:51 GMT
Dust would still be hilariously less effective than an equivalent-mass plate of solid armor (the Atomic Rockets link above covers this very well), and as for cooling, well, you run into the issue of "how much spare space and mass budget do I have for the gas tanks I'll need"? big thing is, its not your hull armour and even a few seconds can make a huge difference You still have to carry all that weight around. The AR link explains this, if you have to carry all that mass around anyway, having it continuously deployed as a conventional armour layer is simply better.
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Post by Enderminion on Jan 10, 2017 18:40:40 GMT
big thing is, its not your hull armour and even a few seconds can make a huge difference You still have to carry all that weight around. The AR link explains this, if you have to carry all that mass around anyway, having it continuously deployed as a conventional armour layer is simply better. say I have 5kt of mass to use for this, I can deploy all 4kt of dust (1kt of support equipment) in one place, although its not the best it can also be retrofit onto existing hulls far more easily then extra armour mass, kinda like torpedo bulges on surface ships
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Post by caiaphas on Jan 10, 2017 19:29:48 GMT
You still have to carry all that weight around. The AR link explains this, if you have to carry all that mass around anyway, having it continuously deployed as a conventional armour layer is simply better. say I have 5kt of mass to use for this, I can deploy all 4kt of dust (1kt of support equipment) in one place, although its not the best it can also be retrofit onto existing hulls far more easily then extra armour mass, kinda like torpedo bulges on surface ships ...I feel as though you are doing two things here. One, you are massively overestimating the efficacy of a dust shield, and two, you are massively underestimating the complexity of these systems (as compared to armor). I'm going to address these in order and then address the issues in your example. Firstly, because the mechanism of laser damage will always be the same (heating to vaporization, eroding away until you get to the juicy unarmored nougat center), and because the density of a dust cloud will always be less than that of an equivalent volume of solid armor made of the same material, a dust cloud will always be, kilo for kilo, less effective at protecting a ship against laser damage than a plate of solid armor, even ignoring the issues with timing and dispersal that are addressed in the Atomic Rockets link under "Sandcasters" which severely degrade its combat efficacy. This means that, in your example, you're not simply going to be able to carry around 5 kt of dust and support equipment and expect to have the same protection as 5 kt of armor plating. Compounding this issue is the fact that you need to carry around support equipment, which means less available mass as compared to the same quantity of solid armor. Secondly, there is not a chance in hell that a dustcaster system is going to be less complex than armor plating. If I want to add more armor, I manufacture it in the appropriate cylindrical shape and rivet it onto the hull (probably not quite that simple, there's going to be additional modifications to the ship superstructure in order to support it while under acceleration, but mass is mass and you'd need to do that for a dustcaster system too; additionally, since the mass is more evenly distributed with armor plating instead of concentrated in one particular spot with a dustcaster module, it further reduces the engineering complexity of the superstructure modifications. There's a reason that my engineering textbooks always use constant-density rods and plates for moment-of-inertia examples). If I want to slap on a dustcaster system, I need to account for a power supply for the sensors and internal circuitry and more circuitry to handle the dispersal system (since if you fire it off too early or too late then it's completely useless, again explained more thoroughly in the Atomic Rockets link). Admittedly this says nothing about the difficulty of retrofitting the ship itself (i.e. how do we bolt this thing down so that it doesn't come loose the instant we hit the thrusters), but it does say something about things further up the logistics chain; a dustcaster system is going to be a lot harder and more expensive to manufacture than a sheet of armor because of that additional complexity. Thirdly, you'll note that torpedo bulges aren't an active system; they're more or less extra bits of hull that were bolted onto ships, which makes the whole "easier to retrofit" argument much more analogous not to dustcasters, but to the attachment of extra armor plating. Fourthly, if you deploy 4 kt of dust in one spot on the hull, that's going to screw so badly with your center of mass (unless you're talking about a warship in the dozens of kilotons, in which case its maneuverability is probably not going to be fantastic anyways) that it's going to severely compromise to maneuver, which compounds the second issue, which is the question of what happens if your enemy comes at you from the side that doesn't have a dustcaster? I can easily deploy a laser drone with an intercept velocity of several kilometers a second to fly by you and zap you on the other side, or send one on an intercept orbit retrograde to you, and then you're screwed. EDIT: another thing I just realized, conservation of momentum is still a thing. If you're shooting off a large amount of dust as a shield, you're going to be imparting undesired vectors to your ship, which could potentially throw off your weapons targeting or expose vulnerable bits of ship (like rocket nozzles) to enemy fire.
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Post by thorneel on Jan 10, 2017 21:41:40 GMT
The only way a sandcaster would work is if it uses highly resistant transparent crystals that diffract the lasers around. The problem is, they will still heat up, and for what I've heard, this makes known materials loose their capacity to diffract light very fast. Also, you would need to stop the cloud from expanding once it is the right size, for example with magnetic fields or by weaving them into a 3D net with nanofibres, which will most probably be very challenging.
One concept I found in a SF book was liquid anti-laser armour: basically a liquid (or at least viscous) form of our beloved Aramid Fiber / Silica Aerogel that is refilled under fire, so enemy lasers have to burn the entire reserve to get through.
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Post by RiftandRend on Jan 10, 2017 22:19:39 GMT
Pockets of armor containing gas might be useful. When a laser burns a hole in the armor, the gas rushes out, attenuating the beam and carrying away heat from the armor. Using this technique, you could fill Whipple shields or use it as a last defense against laser damage. In this way it's sort of like reactive armor.
Of course, the enemy could just wait for all the gas to escape and then fire again, in which case you're dead.
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Post by coaxjack on Jan 10, 2017 23:15:25 GMT
That's the thing- unless you can get the hell out of there in a hurry, and even something ridiculous like 30 g's of acceleration might not be enough, they can wait 15 seconds to hit you again. They won't have to of course if the crew is in a highly compressed layer of chunky jelly at the aft end of the crew compartment.
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