What can counter Laser weapons? MKII

[Sillychris]

Anyone play Zelda: Link to the Past? MIRROR SHIELD!

But seriously, smoke. Really dense black choking smoke. Or a rainy day. Your choice.

[Sillychris]

There is no difference. Deflection and reflection are the same thing; it's just that deflect is normally used for physical objects, and reflect for wave phenomena. "The angle of incidence is equal to the angle of reflection" is equally true in both cases.

Your statement is only correct in the specific case of perfectly elastic collisions.

[Rakaydos]

Your statement is only correct in the specific case of perfectly elastic collisions.

Given that light (and thus lasers) is perfectly elastic, it seems reasonable enough for this topic.

[Guest]

Some kind of mega mirror? lol

Or a black hole..

If you had the time to build it far enough from earth in the laser trajectory (for a death star like laser)

Edited March 12, 2014 by RevanCorana

[KASASpace]

Actually, perhaps this would be the ONE case where building a ginormous vessel helps out.

The gravity well could distort the laser enough that it misses or loses energy.

[Accelerando]

ice shield absorbs the heat of the beam and vaporizes. very high ∆V spacecraft could jink out of the way with verniering thrusters

what do you think?

[kinnison]

Ice? a laser would cut through that like a hot knife.

I would counter it with my ship having a bigger better laser, or more of them.

Or better yet stealth, so they wouldn't know where to aim

[Seret]

Actually, perhaps this would be the ONE case where building a ginormous vessel helps out.

The gravity well could distort the laser enough that it misses or loses energy.

Except that the gravity well would bend the light towards the ship.

[thelegendaryblah]

the problem with all the heatsink posts is that a laser is very focused (high energy:surface area ratio), unless your spacecraft is made out of super conductive materials, the point being focused on will be destroyed first because the heat builtup at the place being hit cannot distribute the heat quickly enough. hence, any "passive" (armour) defenses would be mediocre at best and should be left as backup

and the problem with the mirror posts is that lasers have varying wavelengths, hence we need a different type of mirror for any different type of laser, since you could only cover one part of your ship with one type of mirror, this made mirror armour unviable

i propose an active system for defense in the fom of a "smoke" grenade loaded onto a small missile/canister. the smoke canister would be filled with a variaty of small particles of "mirror dust" (for different wavelengths) for refracting the focused beam into a much less focused beam, some of the beam would be absorbed by the mirror particles and some of the beam that came out would then proceed to completely miss the spacecraft whilst some of them would be spread out to hit the whole spacecraft's outer shell to distribute the heat evenly

the smoke canister would be released around the spacecraft when it is going into battle(or expecting an attack)

the following picture describes what i mean

black denotes the ship

blue denotes the smoke particle released by the smoke grenade/missile

red is the laser

[Mecha Pants]

Some modern tanks actually use a similar system to disrupt laser guided missiles.

I'd go for a more proactive approach, and build a system that detects the emitter lens coming on target and fires another laser into the weapon assembly to disable it.

Edited March 23, 2014 by Mecha Pants

[thelegendaryblah]

Some modern tanks actually use a similar system to disrupt laser guided missiles.

I'd go for a more proactive approach, and build a system that detects the emitter lens coming on target and fires another laser into the weapon assembly to disable it.

don't you think it it would be way too hard to implement such a system and way too easy to counter it?

to implement such a system, you would have to first have lasers that could fire way faster (loading time I mean, not fire rate), then you need to put those lasers atop a turret that could aim really quickly (quicker than the opponent's laser to fire, then you need to put those turrets all round your ship to cover every blind spot, and even then, you would still need sensors powerful and quick enough to check all possible angle for an attack and then relay commands for your turrets to shoot before the enemy even fired, isn't this kinda hard and expensive?

and to counter it, the opponent simply has to put a shutter on their laser emitter, and open the shutter just before they fire so that your sensors won't be able to pick it up

And let's not forget that we are in space, it's a long distance and the engagement range would be at least a few light second, so that means your quickest possible time to response would be:

detection time+ distance * 2 (your laser has travel time too)

and mentioning light delay issues, if the enemy is moving around, you won't even be able to hit the place you aimed for precisely, The enemy's laser emitter would simply be too small a target to possible hit due to physical restrains of the laser's travel time (light speed does not mean instant hit in space)

[Mecha Pants]

I'm not saying it would be easy, but I'm also not saying it's an unworthy effort.

At ranges where Laser accuracy become about more than simple hardware precision it cuts both ways equally. Your target might rabbit as soon as you try to get a targeting fix, before your sensors get a solid lock.

In space there is no stealth to speak of, other than physical isolation (on the other side of a larger object or what have you). The act of bringing an active targeting system to bear would be like shining a flashlight on someone in a dark room. Your target immediately knows that it has been painted and from where, before your Targeting equipment even get the return ping. At that point it comes down to system reaction time. The attack itself isn't where things would start moving, but the act of targeting.

I'm thinking about one laser pulse system with multiple small emitter arrays scattered over the hull of a ship, paired with some variety of ablative armor to buy just a little time for the counter battery to locate any active lasers and fire. Ideally, the arrays would be set up in clusters of several small emitters and placed in such a way that the onboard computer could roll the craft in response to being targeted and swap from one random emitter in an array to another as they came into arc. This would spread the damage from the incoming attack over a larger percentage of the armor, buying more time, and make it harder to damage the laser system by targeting the dispersed emitters (so it's harder to do this same thing back).

It would be walking a razor's edge, but it would be a workable defense mechanism. These emitters and their attached laser pulse systems wouldn't need to be as big as the sort used to cut into armor because they don't need to. So they could be reasonably expected to more nimble than their larger cousins.

Laser emitters are always going to be the weak link in the system, you can't armor the lenses and focusing systems themselves, and by their very nature those same lenses and focusing systems will amplify an incoming laser as it directs the pulse right back into the heart of the system where it can do the most harm.

Even if you shutter the emitter there will be residual heat and other evidence to pick any emitter that has been used out and target it, after which it's just a matter if buying time for the defense laser to do its thing. And as you can't hurt someone with your lasers shuttered the defense system has all the time in the world.

Edited March 23, 2014 by Mecha Pants

[thelegendaryblah]

i see, so you are suggesting an actual system for space combat (at least as far as lasers are concerned), but i still dont see how one could hit the enemy's emitters reliably

At ranges where Laser accuracy become about more than simple hardware precision it cuts both ways equally.

the thing is, the enemy is trying to hit your whole ship whilst you are trying to hit a very small fraction of their ship, as stated from my previous post, the margin of error for one's aim increases as the engagement range increases due to light's travel time. since this thread is about countering, this would mean that the enemy would most certainly engage in such a range that the margin of error is good enough for a beam to reliably hit an enemy ship, but not precise parts of an enemy ship.

In space there is no stealth to speak of, other than physical isolation (on the other side of a larger object or what have you). The act of bringing an active targeting system to bear would be like shining a flashlight on someone in a dark room. Your target immediately knows that it has been painted and from where, before your Targeting equipment even get the return ping. At that point it comes down to system reaction time.

i agree with you for the first part, indeed there is no stealth in space because ships are hot and space is not, a simple IR lidar or something similar would detect anyting in a very long range. however, this is precisely why i do not agree with the second part. i would suggest that because space is so un-stealthy, all ships will always be shown on lidar anyway, in other words, all ships are always being targeted by any other ship anyway. the act of being painted by a targeting/detecting system would not warrent anything to do with an incoming attack.

I'm thinking about one laser pulse system with multiple small emitter arrays scattered over the hull of a ship

this is actually very practical because the multiple emitters could share the same capacitor bank for power (you suggested pulsed lasers so i assume its capacitor powered/fed)

the onboard computer could roll the craft in response to being targeted

as explained on my second point, the onboard computer probably wont know its being targeted until it's being hit, regardless, rolling after being first hit is still a good idea anyway

for the counter battery to locate any active lasers and fire

as stated before, i dont see any reason why one could reliably hit any of the enemy emitters reliably when an emitter is so much smaller than an entire ship

These emitters and their attached laser pulse systems wouldn't need to be as big as the sort used to cut into armor because they don't need to. So they could be reasonably expected to more nimble than their larger cousins.

indeed, i agree with you completely on this, but i still feel that the limiting factor is engagement range, i feel that lag due to light's travel time is still the big limiting factor over here

Laser emitters are always going to be the weak link in the system, you can't armor the lenses and focusing systems themselves,

you are correct, the emitters are indeed the weak link, but remember that you only cant armor the lenses when you are firing, when you are not, you could hide your emitters behind shutters

by their very nature those same lenses and focusing systems will amplify an incoming laser as it directs the pulse right back into the heart of the system where it can do the most harm.

we should probably keep in mind that we are dealing with varying wavelengths over here, unless your lasers have a similar wavelength as the opponent's lasers, the enemy's lense will not amplify your own laser, the lense might even act as a mirror for your laser at worst

also, if you are familiar with a laser cutter, then you will known that it works by reflecting the laser beam of one-large-stationary emitter off of a series of moving mirrors to hit a specific location. if the opponent's laser is something similar to modern-day laser cutters, then this combined with what i said above regarding wavelengths means that even if you magically hit one of the enemy's "emitter", it would probably just break a mirror that could be easily replaced

all being said, your system does have some advantages over my suggestion of some sort of smoke grenade, for example, your system allows for retaliation whilst my "mirror powder smoke grenade" means my own counterattack would be as ineffective as the enemy's attack (unless my smoke grenade allows a certain wavelength through). i just dont see the point in setting up such as complex system like what you suggested, i feel it would be more practical to just roll and shoot back with your own large-arse laser if you wanted to retaliate

maybe some variaty of a moving armor would work well? maybe a series of "shields" strapped to rails on your spacecraft that could move itself? this would be easier than rolling your whole spacecraft depending on the (armor:ship mass ratio)

[Javster]

Be hard to detect, so the enemy don't fire a laser at you in the first place?

[KASASpace]

Except that the gravity well would bend the light towards the ship.

and if not too massive, around the ship. I'm not saying it's going to get a direct hit and be deflected around the entire ship, I'm saying that if you don't get a good shot, the gravity well will be the defense's best shot.

Of course, I would rather be a few light minutes away and let them fire, and then move, so they get a dead on miss and have to wait a few minutes to tell if it was a hit or not.

[KASASpace]

Be hard to detect, so the enemy don't fire a laser at you in the first place?

In space that isn't really possible, and space is probably where laser weapons will be most likely to be used.

However on the ground they can use a number of different ways to find you and even shoot you from orbit.

[DaveofDefeat]

This whole destroying the others guys laser thing confuses me, if you could reliably hit the enemy's lasers, why not go all the way and just destroy their entire ship?

[KASASpace]

This whole destroying the others guys laser thing confuses me, if you could reliably hit the enemy's lasers, why not go all the way and just destroy their entire ship?

Salvage. Free ship for the taking.

[Seret]

i agree with you for the first part, indeed there is no stealth in space because ships are hot and space is not, a simple IR lidar or something similar would detect anyting in a very long range.

This is only the case where the background is space, rather than something else. Combat isn't going to take place in interplanetary space, there's nothing there to fight over. Ground stations would probably have a tough time tracking things in Earth orbit thermally, they're looking through the atmosphere, which sucks for IR wavelengths. It could work on planets with atmospheres that were more forgiving in the IR. Vehicles in low orbits would have a good chance of picturing enemy against a space background, and being in a low orbit shortens the distance to the horizon, so you can be bounced that way. Radar tracking is still likely to be useful, as it can be used from both the ground and a high orbit. So stealth could well be tactically advantageous.

[thelegendaryblah]

This is only the case where the background is space, rather than something else. Combat isn't going to take place in interplanetary space, there's nothing there to fight over. Ground stations would probably have a tough time tracking things in Earth orbit thermally, they're looking through the atmosphere, which sucks for IR wavelengths. It could work on planets with atmospheres that were more forgiving in the IR. Vehicles in low orbits would have a good chance of picturing enemy against a space background, and being in a low orbit shortens the distance to the horizon, so you can be bounced that way. Radar tracking is still likely to be useful, as it can be used from both the ground and a high orbit. So stealth could well be tactically advantageous.

right now, nasa could track space junks with sizes down to 1 cm with its telescopes and space junks with sizes down to 10 cm with its lidar/radar, are you seriously suggesting that when lasers became practical as weapons, we would not have sensors better than what nasa have right now?

anyway, i was under the assumption that the combat must be space-to-space or at least under long distances in vacuum because lasers really only shine when there's a vast distance to cover. the best modern lasers we have are about an order of magnitude less powerful that the balistics weapons we have of the same scale with huge energy consumption issues, but of course this will definitely change when capacitors became better and better and maybe even phase out batteries

[Sillychris]

and if not too massive, around the ship. I'm not saying it's going to get a direct hit and be deflected around the entire ship, I'm saying that if you don't get a good shot, the gravity well will be the defense's best shot.

Of course, I would rather be a few light minutes away and let them fire, and then move, so they get a dead on miss and have to wait a few minutes to tell if it was a hit or not.

How would you know to dodge in advance of the laser's arrival? You wouldn't know a laser was en route until it arrived. Of course, you could just juke around randomly to make it impossible for the enemy ship to predict where you will be in a few minutes. I suppose the enemy ship could saturate all your possible positions at that point in time, assuming they had enough power.

"What, are we paying by the laser now? -From Family Guy parody of Star Wars.

[KASASpace]

How would you know to dodge in advance of the laser's arrival? You wouldn't know a laser was en route until it arrived. Of course, you could just juke around randomly to make it impossible for the enemy ship to predict where you will be in a few minutes. I suppose the enemy ship could saturate all your possible positions at that point in time, assuming they had enough power.

"What, are we paying by the laser now? -From Family Guy parody of Star Wars.

Well, you wouldn't know, but you could get lucky, because you would see them a few light minutes away as well and would definitely move.

Although if they had that power they could just leave the solar system or something.

That is one of the best quotes ever, BTW.

It's when they almost shoot Quag-3PO and Cleve-2-D2

[Seret]

right now, nasa could track space junks with sizes down to 1 cm with its telescopes and space junks with sizes down to 10 cm with its lidar/radar, are you seriously suggesting that when lasers became practical as weapons, we would not have sensors better than what nasa have right now?

Sure, but I was responding to the suggestion that stealth would be non-existent because IR sensors would be able to spot anything. Radar and optical can be degraded by low-observables so I wouldn't rule stealth out, especially if you're trying to track something that can change its orbit, which kind of goes without saying for a combat vehicle.

[Sillychris]

Well, you wouldn't know, but you could get lucky, because you would see them a few light minutes away as well and would definitely move.

Although if they had that power they could just leave the solar system or something.

That is one of the best quotes ever, BTW.

It's when they almost shoot Quag-3PO and Cleve-2-D2

I remember seeing Star Wars for the first time and thinking not shooting that pod was a really weak plot device. I wonder if the guy that gave that order got fired.

I really want a star wars style plasma/laser type gun. Maybe like a death ray.

[KerikBalm]

There's pretty much no counter to an X ray laser. The range of just a 10 meter focusing array and a 1 gigajoule pulse will extend several to dozens of AU (depending on the specific wavelength), at those wavelengths, only grazing incidence mirrors will work, if your mirror is at less than about 1 degree from parallel with the incoming photons, it won't reflect, and you're screwed.

Pulse lasers will vaporize the surface, and literally cause an explosion - and its much more effective than slowly melting through your target.

The only thing better than an X ray laser, would be a gamma ray lazer... but good luck focusing that thing....