Space Laser and warfare

[statickid]

Hey, I've always wondered this- I don't know much about theoretical high powered lasers, but whenever i'm watchin sci-fi movies i can't help but wonder this:

If people are having laser battles, what would stop people from just having super reflective mirrored ships (or deployable shells) that just reflect the lasers off of them>>?:OMG:

Also, whats so hard about aiming a laser at someones ship? whats with all these people "missing" their laser targets????? YOU'RE FIRING A LASER! you can't outrun or outmaneuver a laser!

the best rendition of sci-fi lasers i've seen are the instant effect ones. off the top of my head, i can think of the beam-lasers in the old game Forsaken that was a console game. these lasers seemed plausible to me as how an actual laser weapon would work.

 

[T.Neo]

No, even relatively weak lasers would simply vaporise the reflective layer and carry on through. The best bet would be something light with a high vapourisation temperature and high strength, and that has problems...

The rendition of lasers in science fiction is almost always totally wrong- lasers can be many things but generally not what they're depicted as in Star Wars etc.


The "heat rays" in HG Wells' War of the Worlds are very much like IR lasers though.

 

[Jarvitä]

Also, whats so hard about aiming a laser at someones ship? whats with all these people "missing" their laser targets????? YOU'RE FIRING A LASER! you can't outrun or outmaneuver a laser

There's the issue of tracking accuracy, aiming mechanisms, ECM, ECCM, et cetera.

And given enough distance, aiming a laser can be just as difficult as aiming artillery. Even a single second of light-speed delay introduces an untold number of variables into the equation - and you're basically shooting at where you predict the target will be.

 

[Izack]

Funny you should bring this up now.
I've had a hard sci-fi novel (like, as hard as one can possibly be) in the works since early last year, and I'm just starting to get into the grittier aspects of space combat. So far, I've found this page to be exceptionally useful, but I'd like to hear some other general opinions on this. If I had my other system up I'd show you what I had so far in the way of notes, but sadly said system is a notepad and doesn't support copy-pasting that well.

 

[statickid]

There's the issue of tracking accuracy, aiming mechanisms, ECM, ECCM, et cetera.

And given enough distance, aiming a laser can be just as difficult as aiming artillery. Even a single second of light-speed delay introduces an untold number of variables into the equation - and you're basically shooting at where you predict the target will be.

yeah i've always figured that a REAL laser battle would have to be done from quite a distance, since once you got up close it would be too easy to hit each other... or rather the opposite reason, people would try to engage as far from each other as possible, simply because they could.

...i thought the heat rays were good too

---------- Post added at 04:20 PM ---------- Previous post was at 04:16 PM ----------

No, even relatively weak lasers would simply vaporise the reflective layer and carry on through. The best bet would be something light with a high vapourisation temperature and high strength, and that has problems...

The rendition of lasers in science fiction is almost always totally wrong- lasers can be many things but generally not what they're depicted as in Star Wars etc.


The "heat rays" in HG Wells' War of the Worlds are very much like IR lasers though.

yeah whenever i see the "usual" sci-fi laser, i figure it must be some kind of hot-matter gun, whatever that is, i mean it seems like they are flinging some kind of object, like an ultra hot pellet or something.

---------- Post added at 04:21 PM ---------- Previous post was at 04:20 PM ----------

yeah i should start more posts with the word "yeah"

---------- Post added at 04:26 PM ---------- Previous post was at 04:21 PM ----------

or how about some kind of optical counter measures, like ejecting a cloud of prisms or dense cloud of cube shaped glass dust and or metal

i can see the really ultra high-powered lasers vaporizing the reflectivity, but what about more near-tech or current tech laser weapons? does anyone know about the strength of those anti-warhead/missile lasers?

 

[T.Neo]

So far, I've found this page to be unbelievably useful, but I'd like to hear some other general opinions on this.

I think space warefare will be between large fleets of spacecraft, mostly drones with a few command centers where manned crews would make on-site strategic decisions and oversee tactical calculations made by flight computers. The drones and manned ships would be virtually indestinguishable, at least from a distance, to avoid the enemy picking off valued targets.

Weapons systems would either be lasers or various nuclear weapons, although both have issues (the effectiveness of a laser diminishes with range, for example). There might be some sort of armor on spacecraft, and they'll use things like heatsinks and droplet radiators to avoid damage to fragile yet essential radiators. Thrust systems would have to be high ISP and high thrust, so beasties like Orion might be ideal even if political and environmental concerns don't allow otherwise (NSWR's fuel storage can cause trouble if damaged, apparently).

RKKVs are the world-ending threat of the interstellar age, but they don't really make sense in interplanetary war within a solar system IMO.

That's what came out of my head, anyway. I'm infamous on the IRC as creator of the Battle Cylinder Mk I, so perhaps I should just shut up:

:lol:

 

[Izack]

I think the best defense against laser weaponry is not in deflecting the beam, but making sure that when it does hit you, it hits somewhere that won't instantly incapacitate the ship or kill the crew. Assuming a laser does primarily thermal damage, it will flash-boil or at least melt the ship's hull on 'impact' (I say impact to keep some parallel with conventional kinetic weapons). With this in mind, if it's impossible to avoid the laser and impractical to deflect, the only option is to absorb it. This can be done in two general ways (note that these are only my musings, and I'm not scientist):
1. Carry an enormously thick outer hull. This is not really a good idea, because greater mass = lower Dv
2. Distribute weak points (Hab modules, engines, for goodness' sake PROPELLANT TANKS) across a large truss/framework, and carry a smaller mass of shield separated from but connected to the framework. Essentially, hide your weak spots behind the shield and hope that if you don't get the first strike, you'll live to make the second.

EDIT: @T.Neo
Sorry, I meant this page at Atomic Rockets. See edited post. My bad.

EDIT 2: Also at T.Neo:
You might like this.

 

[T.Neo]

1. Carry an enormously thick outer hull. This is not really a good idea, because greater mass = lower Dv
2. Distribute weak points (Hab modules, engines, for goodness' sake PROPELLANT TANKS) across a large truss/framework, and carry a smaller mass of shield separated from but connected to the framework. Essentially, hide your weak spots behind the shield and hope that if you don't get the first strike, you'll live to make the second.

What about making the armor and the propellant the same thing? If the propellant is water, the spacecraft could be covered in ice perhaps wrapped in a thin coating to prevent it subliming in the sun. It would absorb laser energy and perhaps thermal radiation from nuclear detonations, and also be used as a large store of propellant. It might also be useful as a very large heatsink.

I'm sure it has numerous disadvantages, but the general concept might be worth considering.

You might like this.

Pretty awesome stuff.

The one visual has an Orion battleship with a deployed thin "laser shield". I originally thought this was some sort of large, flimsy whipple shield.

Another idea that wondered into my head- blinding enemy sensors with lasers during a burn, so that they wouldn't be able to tell where you are going by looking at the characteristics of your exhaust stream.

It would of course tell them where you are, but that doesn't matter much because they've already detected you...

 

[Izack]

What about making the armor and the propellant the same thing? If the propellant is water, the spacecraft could be covered in ice perhaps wrapped in a thin coating to prevent it subliming in the sun. It would absorb laser energy and perhaps thermal radiation from nuclear detonations, and also be used as a large store of propellant. It might also be useful as a very large heatsink.

I'm sure it has numerous disadvantages, but the general concept might be worth considering.

That's a good idea! Talk about out-of-the-box thinking.
Of course, what isn't OOTB in space travel?

 

[Andy44]

In Jerry Pournelle's novels, lasers pretty much never miss once you are close enough. The warships are equipped with a handwavium spherical shield called a Langston Field which absorbs the laser energy and re-radiates it. The bigger the ship, the bigger the sphere, and the more surface there is to radiate, so when a fight starts it's all a mathematical game to see who wins.

If we ditch the handwavium and assume some sort of ablative armor, then it's just math to see how long it would take a given laser to burn through. If one ship is a steadier pointing platform than the other, then a high-speed pass would be in its favor, since it could do more damage in a shorter period of time.

 

[statickid]

.....

2. Distribute weak points (Hab modules, engines, for goodness' sake PROPELLANT TANKS) across a large truss/framework, and carry a smaller mass of shield separated from but connected to the framework. Essentially, hide your weak spots behind the shield and hope that if you don't get the first strike, you'll live to make the second.

............

true, although it almost seems there there aren't many superfluous areas of most spacecraft.

get shot in the hab module: crew dies
get shot in the radiator structure: ship overheats
get shot in the fuel: stranded on bad course
get shot in the guns: harmless
get shot anywhere: perhaps you're going to lose your life support/electrical/control/communication

getting shot at all seems like a bad situation!

the ice armor seems cool.

i was looking at all the guns on those ships you posted, for the non-laser type you'd have to have to be bristling with micro thrusters and shock absorbers for canceling out all the forces at work from launching and firing guns. all over the place.

 

[Izack]

the ice armor seems cool.

Pun intended? :rofl:

I didn't explain myself properly before. The important components of the ship (habs, heat sinks, radiators, engines, etc.) would be dispersed across a skeletal framework, which would be hidden behind an adjustable shield (adjustable because all-around protection is useless...if you're in the middle you're dead anyway). Weapons would be buried inside the shield so they could fire without having to move the shield out of place.
Incorporating T.Neo's idea, the shield could serve as reaction mass. a metal/unobtainium structure filled in with water ice, or even solid rock. Preferably rock, as water is quite heavy and will weaken if the weapons get hot.

I really wish I could draw so I could better describe what I'm talking about. The closest example I can think of is trying to hit a Shuttle-A if it were protected by a slab of metal. The thing's mostly framework, so a directed energy weapon would have to hit near an engine/propellant tank to do damage (of course, you could structurally damage the central support truss to an extent where the main engines were no longer usable...:hmm

Alternatively to the weapons-in-shield idea, remote drones carrying the necessary weapons/radiators could be linked to the main ship via cables, so they could fire far away from the ship without needing to lug around a fusion reactor.

 

[statickid]

what about launching attack probes that preceed your main base? no need for cables, just radio com. or hide behind an asteroid, and launch an expanding ring of attack probes!!!

hail

 

[Izack]

what about launching attack probes that preceed your main base? no need for cables, just radio com. or hide behind an asteroid, and launch an expanding ring of attack probes!!!

hail

Any high-powered laser weapon is going to require a power source. I proposed cables to keep the drones as small and light as possible.

If you're going to bring the Holy into this, we're getting into WMDs...like, galaxy-destroying ones.

 

[Hielor]

or how about some kind of optical counter measures, like ejecting a cloud of prisms or dense cloud of cube shaped glass dust and or metal

i can see the really ultra high-powered lasers vaporizing the reflectivity, but what about more near-tech or current tech laser weapons? does anyone know about the strength of those anti-warhead/missile lasers?

Traveller had this, and called them sandcasters. Decently effective against lasers (for a time, but the cloud would spread out/be ablated and lose effectiveness over time), not particularly effective against other kinds of weapons.

 

[Izack]

Traveller had this, and called them sandcasters. Decently effective against lasers (for a time, but the cloud would spread out/be ablated and lose effectiveness over time), not particularly effective against other kinds of weapons.

According to the linked site they were more geared toward abrading incoming projectiles and missiles. I think they would be more effective as counter-laser defenses as you said, though. Especially the versions held in place by a magnetic field.

Unfortunately, I have very little knowledge of lasers. So far in my drafts I've taken some artistic license (gasp) with my depictions: invisible unless passing at a very acute angle (IE nearby), phasing through the spectrum from more blue towards its point of origin to more red in its direction of travel. It would make a red circle on the hull of the craft it hit for am instant before that hull violently melted (you could say burst into a molten plume). If a propellant tank were hit, the water (nuclear saltwater rockets were used) would flash-boil, resulting in further damage and wild angular velocity/trajectory anomalies.
I'm sure I'm incorrect in at least most of what I said. Any pointers?

 

[Hielor]

According to the linked site they were more geared toward abrading incoming projectiles and missiles. I think they would be more effective as counter-laser defenses as you said, though. Especially the versions held in place by a magnetic field.

Well, at lower tech levels in Traveller you don't have laser weapons being widely used, so I suspect that page was more geared toward the lower end of the tech spectrum. The other main descriptive page about sandcasters lists them to be specifically designed to ablate laser fire, which is what I guess I was thinking of.

 

[statickid]

whats Traveller?

 

[Hielor]

whats Traveller?

http://www.lmgtfy.com/?q=Traveller

 

[statickid]

well i'll be darned. i just came up with that off the top of my head! who knew it was already such an established idea!