[NGTM-1R]

This is why I postulate above a certain calibur railguns/other KEWs will have a bursting charge. Not for damage, but so they don't pose a threat to ground-based objects.

[headdie]

According to the Warhammer 40K quotes in the rulebook:

"There is no arguing with the barrel of a gun."

According to me:

"There is no arguing with a tungsten-jacketed, depleted uranium-cored sabot round!"

 

that will be old tech by then it will be some exotic crystal or alloy that cant be created now

[Mika]

though your sabot would probably burn up in a planetary atmosphere now the question is what happens the the thin hulled colony ship that gets hit by those same sabot shells

And even more worrifying, what happens to the blibjoe when the remains of that thin hulled colony ship drop on him at his backyard?

Besides why the usage of chaff in space combat was brought up only now? Just add separated ECM decoys for that matter.

By the way, mass-driver type weapons have one kind of advantage: they don't necessarily require direct line of sight. Actually lasers could follow curved trajectories at the proximity of massive celestial body, but you can guess which curved trajectory is easier to achieve.

[Thaeris]

We've been discussing ECM. Das General has stated that ECM... as we currently employ it... might not be viable in a vaccum. Thus, if you create an "environment" about your weapon system (the chaff/flare field), you might achieve some success.

I'm not entirely sure why/how the "ECM won't work" thing is currently valid or worth considering, apart from the fact that General Battuta generally has very good points... I need to do some personal research. The only thing I can assume is that the emissions projected by ECM rely on the atmosphere to achieve the desired affect. In general, though, ECM is merely a means of disrupting/distorting a signal so as to provide an inaccurate reading to the hostile emitter. In that sense, I don't see why it wouldn't work.

...Might be time to crack out the physics book...

@ headdie:

It's a good thought, as science and engineering are always producing newer, better materials. However, both elemental tungsten/tungsten alloys are incredibly tough materials. They're used as high-end AP rounds today. Uranium is wicked-dense and is also a choice projectile because of its incredible mass. Get it going at speed... despite K=(1/2)mv^2 (only one-half mass), you've got one helluva punch (the A-10 fires depleted uranium rounds from its GAU-8 cannon). Not to mention that awesome spall upon impact...

In short, be careful of citing "unobtanium" without just cause. 

[Uchuujinsan]

One second is barely anything in space warfare, where you'll know the enemy's precise vector minutes or hours in advance. And keeping the laser on the target is a trivial challenge compared to intercepting it with a KEW. Remember, the laser moves at lightspeed.

Just curious, what would you do with a laser if I have rotating armor plates?
If it takes ~2s for a full rotation, not only will it be hard to determine the exact amount of rotation, hitting the same spot for longer than 1s will be completely impossible. Even times less then 1s will be ineffective, as you won't be able to get a 90° hit on the armor at the same spot after fractions of a second.

[edit]
I tried to calculate the effective sensor range, using the hubble space telescops resolution.
Result: After ~85 million km distance you got an error of ~100m.

[Liberator]

On lasers:
One meter of armor of ANY kind, even polystyrene, is a crap-ton of armor, but it also weighs a hell of a lot.  It would probably account for more weight than the propellant.  And, frankly, a laser can be defeated by any decent hull refrigeration system, which deep space craft are likely to have to combat solo-side heating issues.  Yes, the coolant is going to have a maximum saturation before it won't absorb any more heat and the dissipation system on the far side of the ship will have a maximum rate as well, but a refrigerated, reflective surface goes a hell of a long way toward defeating a laser based weapon system.

Practically speaking, with the exception possible planetary warfare(battle directly between two planets where the planet itself is the target), most space battles are going to be at the so-called "knife fight" ranges outlined above.  Simply because the further you get from your target the less accurate ANY weapon gets.

Also, practically speaking, it would be much easier to kill the crew of an opposing ship than to actually destroy the ship.

[General Battuta]

One second is barely anything in space warfare, where you'll know the enemy's precise vector minutes or hours in advance. And keeping the laser on the target is a trivial challenge compared to intercepting it with a KEW. Remember, the laser moves at lightspeed.

Just curious, what would you do with a laser if I have rotating armor plates?
If it takes ~2s for a full rotation, not only will it be hard to determine the exact amount of rotation, hitting the same spot for longer than 1s will be completely impossible. Even times less then 1s will be ineffective, as you won't be able to get a 90° hit on the armor at the same spot after fractions of a second.

[edit]
I tried to calculate the effective sensor range, using the hubble space telescops resolution.
Result: After ~85 million km distance you got an error of ~100m.

Rotation is probably a great idea. However, it works against you just as much as it works for you, doesn't it?

However, it's a great anti-laser defense, and in SDI projections, it about triples the amount of beam energy required to kill the target.

On lasers:
One meter of armor of ANY kind, even polystyrene, is a crap-ton of armor, but it also weighs a hell of a lot.  It would probably account for more weight than the propellant.

The one-meter figure is indeed a crapton of armor, more than is remotely practical. It was cited to show how powerful laser weapons can be. Please make sure you read and understand posts before replying.  

And, frankly, a laser can be defeated by any decent hull refrigeration system, which deep space craft are likely to have to combat solo-side heating issues.  Yes, the coolant is going to have a maximum saturation before it won't absorb any more heat and the dissipation system on the far side of the ship will have a maximum rate as well, but a refrigerated, reflective surface goes a hell of a long way toward defeating a laser based weapon system.

No, it doesn't. Reflective surfaces are not an effective defense against lasers, because no mirror is 100 percent efficient and the leakage will annihilate the mirror almost immediately. In fact, laser systems often contain mirrors, which must be specially designed so that the laser beam will not melt them (the beam is diffuse until it is focused by a mirror.)

Lasers do not work by gradually heating the target. They work by cutting. A hull refrigeration system, presumably some kind of coolant circulating through the hull, would just reduce the hull temperature. Is ice any harder to cut than steel (or, for that matter, frozen steel vs. regular steel) when you're using a blowtorch? Same with a laser.

The difference between a normal-temperature hull and a cooled hull is not going to be more than a hundred or two hundred degrees Kelvin. The laser will heat a point target by thousands of degrees (or more?)

Unlike spinning rapidly, these aren't effective laser countermeasures (particularly the mirror!)

Practically speaking, with the exception possible planetary warfare(battle directly between two planets where the planet itself is the target), most space battles are going to be at the so-called "knife fight" ranges outlined above.  Simply because the further you get from your target the less accurate ANY weapon gets.

No, completely untrue. Missiles and drone kill vehicles do not suffer such accuracy degradation, only travel time. With massive detection ranges and comparatively sluggish engines, long-range battles will probably be the order of the day.

Also, practically speaking, it would be much easier to kill the crew of an opposing ship than to actually destroy the ship.

If the ships have crews. But, yes, that's probably true.

[Mika]

I think you guys need to review your laser physics. And also optics, while you are at it.

In fact, laser systems often contain mirrors, which must be specially designed so that the laser beam will not melt them (the beam is diffuse until it is focused by a mirror.)

The bolded part is false and something what you absolutely should not do.

I wonder where did you get that one metre of steel in one second number? And how was it measured?

[Mika]

By the way, if rotating armored surface would be used, one would need to be very careful with associated moments of inertia. If that slab goes out of balance, it will cause consequences to the ship it is supposed to be protecting. In some cases it could be vibrations, some cases could result in support structure ripping out of the hull and when **** hits the fan the armor plate buries itself to the hull - which would probably be the most likely outcome [Mr. Murphy].

[General Battuta]

By the way, if rotating armored surface would be used, one would need to be very careful with associated moments of inertia. If that slab goes out of balance, it will cause consequences to the ship it is supposed to be protecting. In some cases it could be vibrations, some cases could result in support structure ripping out of the hull and when **** hits the fan the armor plate buries itself to the hull - which would probably be the most likely outcome [Mr. Murphy].

The ship itself can rotate on its axis. A centrifuge-based armor system is a really bad idea.

I think you guys need to review your laser physics. And also optics, while you are at it.

In fact, laser systems often contain mirrors, which must be specially designed so that the laser beam will not melt them (the beam is diffuse until it is focused by a mirror.)

The bolded part is false and something what you absolutely should not do.

I wonder where did you get that one metre of steel in one second number? And how was it measured?

Take the problem here. I'd be happy to hear a more thorough explanation of the issue if you're so inclined, but the use of mirrors to focus diffuse laser beams onto a point is commonly brought up in respectable and accredited engineering discussions.

[Flaser]

I always wonder why you don't make the same arguments against other weapons.

If an enemy ship can move fast enough so that lasers have difficulty handling aiming, what does that say about other weapons whose ammunitions travel at sub-light speeds?  

Because other weapons don't have to keep hitting the same spot? That is a big problem, regardles of what Batutta is telling you. Depending on speed, the ship can move hunderds of meters in the space of a second.
A missile or mass driver has to hit it..anywhere..once. If the laser doesn't hit the same spot, the damage it ends up doing is superficial.

Lasers are the most accurate and fast weapon by far, but they do have their problems.

"Lasers are drills" - this is a good but farcical allegory.

Actually lasers are really tight and powerful lamps. It's funny that with proper modification for instance it's really easy to permanently blind most sensors with a laser. Just spread it out, and the sensors own lenses and focus mechanism will fry them.

Tighten the beam and first you get a mediocre remote heater. Even in this phase it can cook-off ammunition or disrupt electronics.

...tighten it more and you get your drill.

However it doesn't end there. Increase the energy concentration by upping the power of the laser and increase the focus and the laser no longer acts like a drill. Instead slowly melting and vaporizing the target it will vaporise it explosively like a gun.

[General Battuta]

Which is actually an issue since the vapor can impede the beam. Thus the pulse laser.

[Mika]

Take the problem here. I'd be happy to hear a more thorough explanation of the issue if you're so inclined, but the use of mirrors to focus diffuse laser beams onto a point is commonly brought up in respectable and accredited engineering discussions.

From the context I know what is meant in that web page. However, diffuse is completely - it actually means the opposite of what is discussed in that page - wrong word to use in that context. It doesn't mean what the author thinks it means.

The correct term is collimated, and should be known by anyone who has done a little bit of work in the field of optics.

[General Battuta]

That's fine, and a fair point.