Space Laser and warfare

[jedidia]

Any kind of projectile would probably at least have some kind of terminal maneuvering system

what about guidance? if they don't have an independant guidance system, it's still pretty tough to direct them into the target in the terminal stage, at least if you're not awfully close. The radar pulse has to reach the enemy ship, gets reflected to your ship, and then the guidance signal has to go all the way again to reach the projectiles... you'll have a three-fold light speed lag, i.e. a whole second if you're 100,000 kilometers from target (which is already pretty close).

 

[Linguofreak]

what about guidance? if they don't have an independant guidance system, it's still pretty tough to direct them into the target in the terminal stage, at least if you're not awfully close. The radar pulse has to reach the enemy ship, gets reflected to your ship, and then the guidance signal has to go all the way again to reach the projectiles... you'll have a three-fold light speed lag, i.e. a whole second if you're 100,000 kilometers from target (which is already pretty close).

Well, I had been assuming independent guidance, but I don't think it's as bad as you think with command guidance. For one, your engagement parameters are going to be determined by your weapon systems. (If you have to close within 100,000, or 10,000, or 1,000 km for your weapons to be effective, then those are the ranges at which battles will occur). For another, a second may well not matter. Spacecraft don't tend to be able to accelerate very hard, especially for sustained periods of time, so your enemy might not be able to dodge fast enough for a second of light speed delay to be a concern. Or, if he can, it's likely to cost him delta-v that he might need for things like getting home, dodging your next missile, a reserve against damaged propellant tanks, etc. Also, you can shave off a third or so of the time you mentioned there by using passive sensors to track the target (ie, missile has a camera, transmits what it sees back to you, you transmit guidance signals back to it).

 

[T.Neo]

Plus, Greenpeace would *NEVER* allow them, even if there were no accidents. NSWR's are *worse* for the environment than Orion, if you can imagine such a thing. Heck, I tend to be fairly anti-environmentalist, and I don't want an NSWR any closer to me than lunar orbit.

I can fully understand the moral concerns of the use of a deathspewer as propulsion for an atmospheric craft, but not as an interplanetary or interstellar one- as long as it did not crash or aim the engines at planets or spacecraft. Once the thing is out of the atmosphere the exhaust products don't really pose a problem (they leave the solar system because they're going at 66km/s) unless they got caught in the magnetic field or something to that effect.

If you're fighting with unmanned vehicles alot, you'll likely see alot of use of *RAMMING SPEEEEEEEED*!

Only if you're willing to destroy infrastructure like that, or the spacecraft are soley designed as engines with guidance systems (missles).

Payload for kinetic kill missles may just be a waste of time; the engines, guidance system and propellant tanks become the payload. The whole system can be very minimalist.

Though developing a high efficiency and low cost (low enough to warrant disposability) propulsion system might be a tad tricky. It could lead to breakthroughs in propulsion of other vehicles though.

Space is big, but it is also dark and cold. I have heard stealth in space compared to stealth among penguins with flamethrowers, wearing night-vision goggles, on an antarctic ice sheet, at night.

That's a pretty good analogy, but in space it's more like your flamethrowers are on all the time.

Well, sortof.

Though space is not empty (to a varying degree); perhaps camoflaging oneself as an asteroid could be possible. You'd have to match the temperature of the debris and their spectral emission properties, which could be difficult at best.

And if the enemy had a good enough catalogue of their asteroids, they might just spot an anomalous asteroid and blast it out of the sky just to be safe...

 

[Izack]

It's sort of irrelevant, but space isn't exactly cold, either.

 

[jedidia]

Once the thing is out of the atmosphere the exhaust products don't really pose a problem (they leave the solar system because they're going at 66km/s) unless they got caught in the magnetic field or something to that effect.

quote from a drillseargent at the citadel from mass effect 2, explaining a mass driver to his recruits. "no matter wheather now, or in a hundred or even a thousand years... if you pull the trigger on this thing, you will ruin someone's day, somewhere, somewhen!"

 

[T.Neo]

It's sort of irrelevant, but space isn't exactly cold, either.

But the "background" of space is.

Space, being nothing but empty space, cannot have a temperature.

if you pull the trigger on this thing, you will ruin someone's day, somewhere, somewhen!"

That is Greenpeace's problem... hopefully they won't whine too much.

 

[Linguofreak]

Only if you're willing to destroy infrastructure like that, or the spacecraft are soley designed as engines with guidance systems (missles).

Well, the big point is that an unmanned vehicle is inherently more disposable than a manned one, both from a human life standpoint and from a material costs standpoint (manned vehicles are going to tend to be bigger for a given level of functionality). Sure, if it's got anything really expensive on board, you won't throw it away too lightly, but at the very least, if you find that you have an asset in a situation where it is overwhelmingly likely to be lost anyways, you'd be much more likely to order a kamikaze strike than if it were manned (and it will also be much more likely to obey the order ). With a manned asset, capture (at least of the crew) is generally preferable to destruction. With an unmanned asset, there is no reason to prefer that the enemy capture it.

Payload for kinetic kill missles may just be a waste of time; the engines, guidance system and propellant tanks become the payload. The whole system can be very minimalist.

Indeed. That is the point of the 3 km/s = weight in TNT rule, AKA Rick's law. It's also the whole point of the term "kinetic kill". Any explosives onboard, aside from nukes, would be bursting charges for the purpose of scattering the missile to prevent over-penetration, rather than the main payload (which would be the missile itself, though I suppose, if you want to be pedantic, that the explosives would count as part of that).

Though developing a high efficiency and low cost (low enough to warrant disposability) propulsion system might be a tad tricky. It could lead to breakthroughs in propulsion of other vehicles though.

If missiles and unmanned warships are kept separate, engine expenses would probably be the thing to do it. Chemical rockets are already cheap enough for weaponry.

That's a pretty good analogy, but in space it's more like your flamethrowers are on all the time.

Penguins are warm-blooded, and ours are using IR goggles. :tongue:

Their body heat corresponds to "housekeeping" radiation: Life support for manned craft, blackbody radiation and reflected light when close to a star, etc.

The flamethrowers correspond to operating engines.

 

[Brycesv1]

if a laser weapon will vaporise any reflective armor. how does one aim the laser in the first place. the argument im getting is that "all lasers that we use are targeted by reflecting the beam off of a mirror to the target". why would the targets reflective armor vaporise but not the targeting mirror?

 

[Izack]

I imagine bending of laser beams would take place in extreme magnetic fields, not literally with mirrors...

(No, this isn't a necro before someone mentions how old this thread is. It's a valid continuation.)

 

[insane_alien]

you can use the mirrors before the focusing assembly. at this stage it is possible to have the beam diffuse enough to not destroy your aiming mirrors.

besides, in the production of the laser pulse mirrors are used. then all you need to do is, aim, collimate and focus.

you could also go the route of aiming multiple lasers to the same spot. so as to make a simulate a bigger laser.

we can and already do generate and control laser pulses that can and do completely overwhelm mirrors. thats infact how we know it happens.

 

[Hlynkacg]

Hey Izack, you still writing that story?

I just ask because I've been working on one of my own. :tiphat:

 

[Izack]

Hey Izack, you still writing that story?

I just ask because I've been working on one of my own. :tiphat:

Kind of. :lol:
It's changed a lot in the year or so since that post, obviously... The notes in question are in fact long destroyed, as well as most of the notes since then, though. It's 100% a mental thing for now.

 

[fsci123]

Ive been working on a hard scifi novel and i have concluded that:
1) Your enemy craft would be a few hundred miles away at least.
2) Your lasers have to be powerful
3) Any laser designed to burn a hole in the hull of a craft would most likely destroy any mirror you have in seconds
4) Drones are not efective in space... They are effective in air sea and land but not space. Its actually better to use smart missiles.
5) Space is the only darkness you cant hide in.

And thats as far as i got.

 

[RisingFury]

Space, being nothing but empty space, cannot have a temperature.

Behold, as I show you the temperature of empty space:

That said, while the universe is mostly empty, it's not completely empty. Each particle has an energy that puts it at a temperature higher than 0 K.

---------- Post added at 11:32 ---------- Previous post was at 11:29 ----------

Ive been working on a hard scifi novel and i have concluded that:
1) Your enemy craft would be a few hundred miles away at least.
2) Your lasers have to be powerful
3) Any laser designed to burn a hole in the hull of a craft would most likely destroy any mirror you have in seconds
4) Drones are not efective in space... They are effective in air sea and land but not space. Its actually better to use smart missiles.
5) Space is the only darkness you cant hide in.

And thats as far as i got.

So, in other words, you're just parroting what you read in this thread.

 

[T.Neo]

Behold, as I show you the temperature of empty space:

Please show me the temperature of a cubic meter of absolute nothing?

That said, while the universe is mostly empty, it's not completely empty. Each particle has an energy that puts it at a temperature higher than 0 K.

But that does not make that much of a difference to say, a person floating out in the interstellar void...

 

[RisingFury]

Please show me the temperature of a cubic meter of absolute nothing?

I'm not much into thermodynamics, but from what I understand, you can define temperature through the vacuum fluctuations and creation of virtual particles.

This universe doesn't contain a cubic meter of 'absolute nothingness'. Even if you clear it of all atoms, there are funky quantum effects.

But that does not make that much of a difference to say, a person floating out in the interstellar void...

Temperature is defined by the average energy of a particle, not by how warm something feels.

 

[Hlynkacg]

Kind of. :lol:
It's changed a lot in the year or so since that post, obviously... The notes in question are in fact long destroyed, as well as most of the notes since then, though. It's 100% a mental thing for now.

:facepalm: I know the feeling. Mine has been a mental thing for a while, I only just started commiting it to paper.

I ended up going with guns/missiles as my primary weapons though. I figured that the large power generation/heat rejection requirements of a suffieciently powerful Laser would relegate them to use on semi-stationary (low Dv) platforms.

In my story Unmanned Drones exist in a lot of support roles (Recon/patrol/logistics) but are considered unreliable in combat due to to the prevalence of advanced electronic warfare systems. (uploading a virus to disable or co-opt your enemy's Drone network being a time-honored tactic)

Engagement Ranges are typically well under a light-second due to targeting difficulties and the afore mentioned prevalence of electronic warfare systems. (Everybody and thier mom is carrying Jammers, Decoys, and other dirty tricks)

Actual combat is similar to a medievil joust. The attacking vessel sets itself on a course that will intercept the enemy's trajectory at close range and high relative velocity. The Enemy then has a choice to either accept the challenge or manuever to evade. If combat is joined there will be a flurry of activity as the vessels pass within a few thousand kilometers of eachother trying to "un-horse" (disable/kill) the other before thier respective trajectories carry them out of effective range. "Battles" generally consist of several hours of manuevering/waiting for a shot and only a few seconds of actual shooting.

 

[T.Neo]

I'm not much into thermodynamics, but from what I understand, you can define temperature through the vacuum fluctuations and creation of virtual particles.

This universe doesn't contain a cubic meter of 'absolute nothingness'. Even if you clear it of all atoms, there are funky quantum effects.

It comes close, it isn't like the temperature in your hand would be convected away, by a "super dense" gas cloud with an atom about every cubic meter.

Temperature is defined by the average energy of a particle, not by how warm something feels.

It is irrelevant. It is not noticably conducting or convecting temperature away from something, therefore its 'temperature' is not as important as the temperature of the air that a fighter aircraft might be flying in, the temperature of water that a submarine is submerged in, or the temperature of the ground that a vehicle or encampment is in the foreground of.

Going into details of the cosmic microwave background and quantum effects, has nothing to do with the original point, which is that interplanetary or interstellar space simply doesn't have a 'temperature' in the meaningful sense that physical mediums such as air, water or soil do (as opposed to the notion that space is "cold" and sticking your head out of the airlock will instantly turn you into a meatsicle).