Space Warfare - How would the ships be built/designed?

[Rakaydos]

So you want to build a supercomplicated stealth guided missile, then hurl it out at 20,000 Gs out of a railgun at awful propulsive efficiency. Yeah, that makes sense. Especially when a solid booster would a better job. :

[erasmusguy]

I think the only weapon you could use in a space battle around the earth would be a net. All the other options risk denying yourself future access to space.

[baggers]

Perhaps, but suborbital means zero speed at apoapsis = no destructive potential. You need moar energy. And there's aiming too - 1 angular second deviation means you will miss by 174 meters at h=100 km. Ideally. Because there's wind too.

You're right about accuracy: that's why Navy aim for a guided projectile for his railgun.

[LORDPrometheus]

Delay is the biggest downfall of a railgun... That and heat dissipation. Though laser based weapons are equally screwed in that regard. Any spaceship will be 30-50% radiator by mass just for propulsion and power gen add in weapons and your dragging plural square kilometers of graphene radiators around. Liquid droplet radiators are a better space saving alternative but still need to be hinge

[baggers]

I think the only weapon you could use in a space battle around the earth would be a net. All the other options risk denying yourself future access to space.

Another solution is making a ship carrying a net after the war, to catch the orbital projectiles remaining afloat.

A tough job for those who have lose that war ^^

(Historicaly, it's what happen to many "small" war criminals: 50 years in jail or 5 year of mine-clearing: your move? )

Edited September 17, 2015 by baggers

[shynung]

Delay is the biggest downfall of a railgun... That and heat dissipation. Though laser based weapons are equally screwed in that regard. Any spaceship will be 30-50% radiator by mass just for propulsion and power gen add in weapons and your dragging plural square kilometers of graphene radiators around. Liquid droplet radiators are a better space saving alternative but still need to be hinge

Or one could forget the radiators, and accept the fact that the railgun or laser turret will destroy themselves after a single shot. Make the spaceships themselves disposable unmanned vehicles, meant to get as close as practical to the target, shoot a single railgun or laser charge, and blow themselves up afterwards. Like that, one just slashed 50% of mission deltaV (that thing's not coming back), along with ditching almost all of those graphene radiator panels.

[erasmusguy]

Another solution is making a ship carrying a net after the war, to catch the orbital projectiles remaining afloat.

A tough job for those who have lose that war ^^

(Historicaly, it's what happen to many "small" war criminals: 50 years in jail or 5 year of mine-clearing: your move? )

You might not be able to launch anything to remove the debris.

[Kibble]

You might not be able to launch anything to remove the debris.

Exactly - if orbital debris is a problem (Kessler!), launching anything else on to orbit is a bad idea, because it will probably also become debris.

[baggers]

Exactly - if orbital debris is a problem (Kessler!), launching anything else on to orbit is a bad idea, because it will probably also become debris.

Maybe you can shot (with railguns! ^^) a solid and big "net" in a suborbital trajectory, and catch some debris previously carefully selecteds. the net may have some sort of airbags for landing.

After a while or 2, you should have cleaned at least one safe orbit for spacecraft launchs.

Edited September 17, 2015 by baggers

[erasmusguy]

Maybe you can shot (with railguns! ^^) a solid and big "net" in a suborbital trajectory, and catch some debris previously carefully selecteds. the net may have some sort of airbags for landing.

After a while or 2, you should have cleaned at least one orbit for spacecraft launchs.

It might be easier to capture whole satellites with a net than tiny pieces of one travelling at 10's of thousands km/s

[Darnok]

It might be easier to capture whole satellites with a net than tiny pieces of one travelling at 10's of thousands km/s

If you can fire piece of metal using magnetic field you can also change its path using magnetic field

[Rune]

Perhaps, but suborbital means zero speed at apoapsis = no destructive potential. You need moar energy.

And there's aiming too - 1 angular second deviation means you will miss by 174 meters at h=100 km. Ideally. Because there's wind too.

Au contraire, my friend. If you can actually make the interception at zero speed relative to the ground, all the better! The target will slam into the round at least at 7.2 km/s (on LEO), which is much higher than your muzzle velocity. The issues are guidance, as you say.

Another solution is making a ship carrying a net after the war, to catch the orbital projectiles remaining afloat.

A tough job for those who have lose that war ^^

(Historicaly, it's what happen to many "small" war criminals: 50 years in jail or 5 year of mine-clearing: your move? )

Actually, we are considering laser 'brooms' right now, both ground and space-based. By ablating the prograde side of a satellite consistently, you can slow it down with a very inefficient form of beamed power that uses the target as reaction mass, and deorbit it. A paper I've seen recently talked about cleaning LEO in a timeline measured in years for an energy budget in the low MW's (because they were firing from orbit already, IIRC), but I can't seem to find it now... Anyhow, the laserstars can very easily clean up the mess they've created after an orbital fight, and will probably act as a short of 'Space Guard' in times of peace, cleaning out debris from civilian orbits and deflecting the odd NEO.

A drone, as in UAV (or, more aptly, USV), is expected to fly back to be refueled and rearmed. This thing doesn't fly back after it delivered the zap; in fact, the reactor core powering it would probably explode mere seconds after it has fired, due to the lack of radiators in an effort to shave off weight, a consequence of its single-shot concept.

This isn't a laser drone, it's a laser missile. To be precise, a guided missile carrying a weapons-grade laser as its offensive payload instead of explosives or kinetic energy.

But then your laser missiles can be defeated by a larger number or warhead-less, cheaper missiles. That's my point against one-off laser drones, missile drones are cheaper and pack the same blam.

I think it's much better for the sensor ports to be inside separate optical turrets, much smaller than the main laser turret, and covered in separate ablative fairings. This way, it can traverse faster than the main turret, an obvious advantage when acquiring a target within a very limited time frame. It also means that the missile can carry several targeting turrets rather than relying on the main laser turret, which means the anti-sensor laser now has several eyes to blind, increasing the chances of the sensors acquiring a target before it gets blinded.

Note that I used fairings, not shutters. An ablative fairing similar to aerodynamic fairings used in orbital booster rockets can be simpler to build and open than a shutter system. Coupled with the fact that the laser turret won't survive firing the laser (due to having no radiators, resulting in it, along with its power source, overheating to Hell), the ablative covering doesn't need to be closed again, rendering the point of shutters moot.

I can even imagine a nastier version. Replace the directional optical sensor turrets with a passive omnidirectional sensor. When its fairing pops open, it lets itself get fired upon by anti-sensor lasers, thereby acquiring the position of the anti-sensor laser turrets. Train the main laser turret to this location, and pop the ablative fairing microseconds before firing. The target ship would have lost one of its laser turrets (possibly along with a few other things), opening the way to more devastating weapons that are more reliant on sensors.

All lasers will use all optical turrets available. Or to be more precise, the single laser will use several optical turrets. The nature of the system is such that a single laser generator can feed several independent optical turrets, at different power levels, with ease. So good idea, but it's unnecessary.

Rune. I'm turning into the laser crusader or something.

[erasmusguy]

Au contraire, my friend. If you can actually make the interception at zero speed relative to the ground, all the better! The target will slam into the round at least at 7.2 km/s (on LEO), which is much higher than your muzzle velocity. The issues are guidance, as you say.

Actually, we are considering laser 'brooms' right now, both ground and space-based. By ablating the prograde side of a satellite consistently, you can slow it down with a very inefficient form of beamed power that uses the target as reaction mass, and deorbit it. A paper I've seen recently talked about cleaning LEO in a timeline measured in years for an energy budget in the low MW's (because they were firing from orbit already, IIRC), but I can't seem to find it now... Anyhow, the laserstars can very easily clean up the mess they've created after an orbital fight, and will probably act as a short of 'Space Guard' in times of peace, cleaning out debris from civilian orbits and deflecting the odd NEO.

But then your laser missiles can be defeated by a larger number or warhead-less, cheaper missiles. That's my point against one-off laser drones, missile drones are cheaper and pack the same blam.

All lasers will use all optical turrets available. Or to be more precise, the single laser will use several optical turrets. The nature of the system is such that a single laser generator can feed several independent optical turrets, at different power levels, with ease. So good idea, but it's unnecessary.

Rune. I'm turning into the laser crusader or something.

You could attach a bb gun to a satellite and it would be good enough. Just shoot backwards away from your orbital direction at something trying to get into orbit and the difference in velocity would take care of it. Or alternatively you could use the ball bearings as a defensive shield by firing several in the path of incoming missiles although that might not be as effective.

[shynung]

But then your laser missiles can be defeated by a larger number or warhead-less, cheaper missiles. That's my point against one-off laser drones, missile drones are cheaper and pack the same blam.

Ah-ha! This is why earlier I postulated that a space missile would carry a variety of offensive payload. There will be missile payloads designed to take on full-size crewed warships (the laser cannon is one such payload), payloads designed to intercept anti-ship missiles (cheap warhead-less kinetics, clustered kinetic missiles, to name a few), payloads designed to hinder enemy activities (ECM, EMP, radio jammers, weak-but-reusable anti-sensor lasers), and payloads designed to defeat especially sturdy targets (railgun-armed missiles, design to go through extremely thick armor, for instance).

In a warfare where laser weapons practically one-shot every sensor they come across, and remotely-controlled one-shot drones are common, there is bound to be several types of them whizzing around. The cheap kinetic ones would be the most common, followed closely by the laser-armed ones.

All lasers will use all optical turrets available. Or to be more precise, the single laser will use several optical turrets. The nature of the system is such that a single laser generator can feed several independent optical turrets, at different power levels, with ease. So good idea, but it's unnecessary.

Sure, it's possible to feed laser beams to the sensor turrets, and make the auxiliary turrets. But now, the sensor turret is optically connected to the laser emitter, which introduces the possibility of an anti-sensor laser slagging the laser emitter by firing the sensor turrets. Sure, we can build ablative shutters in them, but that would introduce an extra part that could fail; if the shutter fails to close in time, there goes the laser emitter.

The point of separate sensor turrets from the main laser turret is to keep the laser emitter and its optical systems as far away from harm as possible until the very final moment. If the sensor turrets are being slagged by anti-sensor lasers, the main emitter is safe, since no optical route exists from the sensor to the emitter. Heat insulation is trivial to design compared to ablative shutters, if the threat of the overheating sensor components are an issue to emitter integrity.

Rune. I'm turning into the laser crusader or something.

And I'm the embodiment of the Macross Missile Massacre. Har har.

Edited September 18, 2015 by shynung

[cicatrix]

You could attach a bb gun to a satellite and it would be good enough. Just shoot backwards away from your orbital direction at something trying to get into orbit and the difference in velocity would take care of it. Or alternatively you could use the ball bearings as a defensive shield by firing several in the path of incoming missiles although that might not be as effective.

Just remember that whenever you fire something from a flying satellite you should deal with recoil. Yes, even if it's a BB gun.

[erasmusguy]

Just remember that whenever you fire something from a flying satellite you should deal with recoil. Yes, even if it's a BB gun.

With the gun attached to a cubesat (1.3kg) I get the ÃŽâ€v to be 0.1. I think we'll live.

[Kibble]

Killer satellites with and without lasers will probably exist. They function the same except a laserstar trades more cost for extra effective range.

[GeneralVeers]

You have a really misguided view of WW2

Either that, or I've got the accurate view and yours is misguided...... That's the problem with being wrong. A person who's wrong never knows it at first. It's something they find out later......

Skipping most of your other stuff and cutting to the chase:

Russia can't beat any major European power in conventional warfare, because it lacks the economic backbone to fight a major war.

Just as Germany's "economic backbone" was inferior to the rest of Europe. They still conquered a lot of stuff.

What Europe lacks right now is a "war" backbone: the willingness to get out guns and shoot people. The whole Iraq-Afghanistan business over the last decade has Europe sick and tired of war--and every dirtbag in the world knows that. Russia is being a jerk because Putin knows he's going to get away with it--Europe is certainly complaining a lot at Putin, but not actually doing anything. Europe of today is making the same mistake they made with Germany: stalling for fear of another war breaking out. History repeating itself.

The enemy with superior tanks can also use every tactic you describe, with the main difference being that their tanks are less fragile. As a result, you always risk higher casualties than the enemy trying the same tactic.

That's not how war works. In fact, that's how war has not worked in the past. Attempts to copycat enemy tactics have backfired many, many times. Por ejemplo, gas warfare in World War I. After Germany used it, Britain tried to copycat--and ended up gassing its own troops a few times. Usually what goes wrong when you copy the other guy's tactics is this: the enemy anticipates that you're going to copycat them, so they know what you're going to do. Does not end well.

Wait, what? Stealth railgun rounds? It's not that, for nth time, there is no stealth in space.

Of course there is. Space is too damn big for anybody to watch all of it all the time. That's why most asteroids that hit Earth never get spotted till after they make atmosphere.

That is a dumb suggestion. I mean, really dumb (the suggestion, not you, no personal attack here, just a figure of speech! ). You are suggesting designing missiles that withstand upwards of 20,000Gs

Doesn't have to be a full-power railgun. Though it probably is possible to build a missile that can handle ridiculous G's.

Launching a missile with a railgun has two huge advantages: number one, the missile isn't using any of its own fuel to launch, giving it longer range. And second, the missile has a much smaller launch transient. It's not producing a huge fireball as it leaves the launch tube, making the launch much harder to detect. (stealth weapons are never about eliminating a craft's signature--that's impossible. it's about reducing the signature enough that enemy radar and IR detection don't pick it up)

Okay, moving on to new stuff: here's a problem with laser weapons that nobody thought of yet.

A laser isn't a hit-scan weapon; it still travels at a finite velocity--300,000 kilomters per second. That may sound like a lot, but at a firing range of ten thousand kilometers, that's 1/30th of a second for the laser to reach its target. Depending on the size and speed of the target, that can easily turn into a clean miss. Bottom line, against anything except immobile targets or capital ships, a laser is going to end up being a short-range weapon.

[shynung]

A laser isn't a hit-scan weapon; it still travels at a finite velocity--300,000 kilomters per second. That may sound like a lot, but at a firing range of ten thousand kilometers, that's 1/30th of a second for the laser to reach its target. Depending on the size and speed of the target, that can easily turn into a clean miss. Bottom line, against anything except immobile targets or capital ships, a laser is going to end up being a short-range weapon.

Today, we have fire control systems able to aim an unguided projectile at a fast moving target, in which the projectile flight time exceeds one second, and still get reasonable hit probabilities. 1/30th of a second is child's play compared to that.

[Jouni]

Just as Germany's "economic backbone" was inferior to the rest of Europe. They still conquered a lot of stuff.

Except that it wasn't. Germany aqcuired a lot of industrial capacity "peacefully" before the war started, and protected its back by making a non-aggression pact with the USSR. Because the US was not yet involved in the war and due to the general apathy of the UK, Germany was always economically superior to its enemies, until it attacked the Soviet Union.

What Europe lacks right now is a "war" backbone: the willingness to get out guns and shoot people. The whole Iraq-Afghanistan business over the last decade has Europe sick and tired of war--and every dirtbag in the world knows that.

Actually, the wars in Iraq and Afghanistan were mostly irrelevant for Europe. Because the involvement of most European countries was symbolic at best, the wars didn't really affect anything outside political debate.

The wars that made Europe sick and tired of war were WW1 and WW2. While the US sent a relatively small number of troops to fight far away from home, suffered rather minor casualties, and just grew stronger during the wars, Europe managed to destroy itself twice in a few decades. As a result, most European countries don't want to have military forces with offensive capabilities, dedicating their forces almost entirely for defensive purposes.

Russia is being a jerk because Putin knows he's going to get away with it--Europe is certainly complaining a lot at Putin, but not actually doing anything. Europe of today is making the same mistake they made with Germany: stalling for fear of another war breaking out. History repeating itself.

Russia already backed down, because the international sanctions proved effective, especially when combined with low oil prices. Russian military is also in decline as a result of the Ukraine war, as Ukraine no longer wants to sell them the equipment they depend on.

And by the way, there is no such political entity as Europe. There are a bit over 50 independent countries in Europe (the precise number is disputed), each of them with their own goals, and Russia is also one of them.

That's not how war works. In fact, that's how war has not worked in the past. Attempts to copycat enemy tactics have backfired many, many times.

And that has nothing to with my point. The enemy could be the one that discovers any particular tactic first, and the tactics would be more effective and less risky for them, because their tanks are less vulnerable.

[cantab]

A laser isn't a hit-scan weapon; it still travels at a finite velocity--300,000 kilomters per second. That may sound like a lot, but at a firing range of ten thousand kilometers, that's 1/30th of a second for the laser to reach its target. Depending on the size and speed of the target, that can easily turn into a clean miss. Bottom line, against anything except immobile targets or capital ships, a laser is going to end up being a short-range weapon.

Predicting the motion of the target is elementary.

Now, the target might opt to be unpredictable. If they expect you to shoot lasers at them they might start jinking around erratically to be hard to hit. But that costs them reaction mass which is finite. True, the fuel to run a laser's power source is also finite, but if your ship uses a nuclear reactor then chances are it might as well be bottomless. So even your laser misses gain you an advantage.

[Heimdall5008]

As so many stated before, it is critical to make some assumptions for the universe we're in. So I will assume a universe with the same laws of physics and no unexpected technological breakthroughs (so fusion power or space elevators are possible, but FTL or translation drives are out of discussion).

To make any sense space warfare has to happen in a setting with more than one permanent (and fully independent) settlement. So let's assume a universe like Leviathan universe from James Corey (a colonized solar system with three power blocks) or the Jump universe from Mike Shepherd (many solar systems connected via "magical" jump points).

So some predictions how warfare could happen under this constraints:

Ships

• Ships will still have a (small) crew. You want to have human control over the fire button, therefore completely autonomous units will not be desirable. And drones only are practical when you have nearly instant communications. With speed of light limitations that is not possible. Even neighbor planets will have some minutes time delay. Therefore you need always at least a control ship nearby. As there is no cover in space the control ships have also to be battle capable.
  
• Ships will probably use some sort of nuclear reactor to heat reaction mass for propulsion (either fusion or fission) and be able to make sustained (low g) burns (at least hours or maybe days). So that they can accelerate the first half of the way and decelerate the second half to shorten travel time, which is still high even compared to naval warfare on earth. Additionally the ships will have thrusters that are capable of erratic, high g, lateral movements (dodging).
  
• Ships will be build more like skyscrapers than (naval) ships. As artificial gravity is out of discussion the sustained burns will be used to simulate at least a partial gravity to soften the effects of microgravity on the crews body. During combat the crew will most likely be placed in some kind of high g stations (semi-liquid shells or so, maybe even liquid breathing) so that they can survive far higher g forces.
  

Weapons

• The most prominent weapons will most likely be kinetic weapons and laser/directed energy weapons (why always only lasers, microwaves to cook any living thing can also be fun).
  
• Kinetics weapons will be used against stationary targets (planets, space stations, ...) as they cannot move and their future positions are completely determined by the Newtonian laws. So attackers can strike from great distances and time away. And there is no real defense against an objects moving at high speed (say up to some per mille to the speed of light) into a gravity well. You can destroy the projectile but then you will just change it from one bullet to shot.
  A dumb tungsten rod of 1000 kg on a highly elliptical orbit (Pe 400 km, Ap 150,000 km) will need only some m/s on Ap to get on a collision course with earth and hit with about the same energy as the Hiroshima bomb and this is just from the "Rods from God" concept. When you go interplanetary the velocities will get much higher...
  The use of kinetic weapons against (populated) planets will probably be banned or proscribed, like nuclear weapons today.
  
• Laser weapons have a lot of advantages but also disadvantages.
  
  • Advantages:
    
    • No ammo, you just need energy
      
    • They travel at speed of light. So your enemy cannot dodge. His best chance to be avoid to get hit is to confuse your sensors (flares, chaff, water vapor...) and randomly make massive lateral movements with powerful thrusters.
      

    [*]Disadvantages:

    • If you speak of powerful lasers you will have to deal with lots and lots of heat. You have to somehow dispose of this heat. Also your lasers will get less efficient when they get hotter. So your firepower will go down with every shot.
      
    • Lasers have a limited useful range. You can use any kinetic weapon over any distance (as long as you can still compute the problem...). Okay, but that can be dodged...
      
    • Lasers will/have to vaporize their target. The plasma will quickly form a very efficient plasma shield in front of the target that should significantly lower the fire power of any further shots.
      

Tactics

• As sterilization of a planet is probably not the goal (habitable room will be too precious), I assume wars will be over resources in space (asteroids, low gravity moons, ...) or about "control of sky/space" ( tributes, travel fees). You could thing about a scenario where a planet will be under siege. You cannot assume that the besieger will positions ships in low orbit. They would be too easy targets for ground based weapons. More likely the besieger would initiate a ablation cascade (Kepler syndrome). That would very effectively stop launches from this planet and (just my assumption) be way easier to avoid/stop when you have control of the space "above".
  
• As all battles will be dominated by orbital mechanics and (complete) stealth is impossible strategic surprises will be very rare or even impossible. So the focus will be on the tactical surprise. The enemy will try to conceal its size/ship type and numbers with different tricks (screen of water vapor, engines used below max power, ...). So you know something is coming but not exactly what.
  
• The first shots will almost always be kinetic weapons long before contact. Even if you have little chance to hit anything you can force the enemy to navigate or use their CIWS and give something of his secrets away. Maybe put one or two nukes in the kinetics for good measure or so...
  
• For the close in (thousands of kilometers ) fights I can think of basically three situations:
  
  • Encounter in open space. There the encounter speed will be incredibly high and the battle will only last seconds and probably achieve nothing. So this will not be the standard battle.
    
  • Encounter in cyclic orbit. The standard will more likely be one side to hold an orbit and the other side trying to conquer it. If they will go in the same direction it will result in a chance around the body. With an advantage to the defending side as they can use ground forces and intelligence against the attacker.
    
  • Encounter in anticyclic orbit. So the most desirable situation for the attacker will be an anticyclic orbit to the defender fleet. Then they will have two shoot outs every orbit (more or less like ships of the line in the old navies). During the orbits both sides will try to navigate while they are below the horizon to surprise the enemy. At the same time they will try to use cubesats to spy on the movements of the enemy.
    

Naturally every battle can be a superposition of all three situations

[GeneralVeers]

Predicting the motion of the target is elementary.

Now, the target might opt to be unpredictable. If they expect you to shoot lasers at them they might start jinking around erratically to be hard to hit. But that costs them reaction mass which is finite. True, the fuel to run a laser's power source is also finite, but if your ship uses a nuclear reactor then chances are it might as well be bottomless. So even your laser misses gain you an advantage.

Of course. Which explains why modern fighter pilots don't bother with evasive action.......

.....errrrrr......wait a minute......

Sorry, bud. No dice. Of course reaction mass is finite. Guess what, evasive action is still a common deal in modern warfare. So it will be in space.

[Rune]

Of course there is. Space is too damn big for anybody to watch all of it all the time. That's why most asteroids that hit Earth never get spotted till after they make atmosphere.

Actually, a full sky survey would take a couple hours. To a single guy. Using a single telescope and computer. To locate all objects inside the solar that have line of sight to him and his telescope can resolve, and compare with the charts for any abnormal motion. Having a few light-seconds around you scanned at all times is as easy as being trivial. We do not look for asteroids, not really. We look for debris in the Moon-Earth system, and we have everything catalogued up to 10cms in diameter. Today.

Doesn't have to be a full-power railgun. Though it probably is possible to build a missile that can handle ridiculous G's.

Launching a missile with a railgun has two huge advantages: number one, the missile isn't using any of its own fuel to launch, giving it longer range. And second, the missile has a much smaller launch transient. It's not producing a huge fireball as it leaves the launch tube, making the launch much harder to detect. (stealth weapons are never about eliminating a craft's signature--that's impossible. it's about reducing the signature enough that enemy radar and IR detection don't pick it up)

But it IS producing a huge fireball leaving the launch tube. Most of the energy spent by the railgun gets wasted as heat! And range... a simple dumb solid booster would give it more range, considering the muzzle velocities of railguns. Then of course, the missile must be built to withstand horrendous mechanical and electromagnetical stresses. Frankly, I am struggling to see any advantage at all... probably the solid fuel in a booster is cheaper than handling the wear of the super-alloy barrels.

I won't even argue stealth with you. Clearly, you have Elected to ignore the laws of physics there, so yeah, have a good one.

Okay, moving on to new stuff: here's a problem with laser weapons that nobody thought of yet.

A laser isn't a hit-scan weapon; it still travels at a finite velocity--300,000 kilomters per second. That may sound like a lot, but at a firing range of ten thousand kilometers, that's 1/30th of a second for the laser to reach its target. Depending on the size and speed of the target, that can easily turn into a clean miss. Bottom line, against anything except immobile targets or capital ships, a laser is going to end up being a short-range weapon.

Are you seriously making the argument that since the speed of light is finite, it's better to go with a slower weapon??? Man, you must really like your railguns. Sadly, a laser weapon IS a hit-scan weapon: if you can see and track the target in its accurate position (say, under a light-second), you can hit the target. By definition. Period. No two ways about it.

Rune. Heimdall, that's a lenghty post. I'll digest it a bit before replying, if I feel like I can contribute.

Edited September 18, 2015 by Rune

[Scoundrel]

A laser isn't a hit-scan weapon; it still travels at a finite velocity--300,000 kilomters per second. That may sound like a lot, but at a firing range of ten thousand kilometers, that's 1/30th of a second for the laser to reach its target. Depending on the size and speed of the target, that can easily turn into a clean miss. Bottom line, against anything except immobile targets or capital ships, a laser is going to end up being a short-range weapon.

Yes and no... you bring up an excellent point, though. There's a couple of issues with laser targeting at extreme ranges - target movement aside:

1) The laser is going to have problems with jitter caused both by vibrations from the vessel's systems as well as from thermal stresses as the ship contracts and expands. In fact all non-missile weapon systems are going to have that problem. I'm pretty sure you can damper most of it, but not all. Thus I would speculate that the maximum effective range of a laser, under combat conditions, would be under 1 million km simply because precision at that range in combat conditions is likely not achievable. An error of 1/1,000,000 mrads at 1 million km means you miss by 10m. In comparison the ALS with its vibration isolated optical bench and beam steering mirrors are only capable of a maximum of about 1/6,000 mrads precision (it may be a little more, it may be much less... the info is classified); for those that think that 1/6,000 mrads precision is meh, consider that current high end stabilized weapon mounts struggle to get better than 1/2 mrads precision. So yeah, lasers are stupid precise compared to anything else. And remember, I'm talking about robust ship mounted weaponized lasers, not fragile high maintenance hyper-accurate low power laboratory lasers on a planet.

2) Sensor error is another factor that we've overlooked. I don't think there is any military-grade sensor that, outside of laboratory conditions, returns 100% accurate readings, and we've not even bothered with EW and optical countermeasures. Those errors, compounded with the jitter caused by the vessel, will likely create an embarrassing number of misses at extreme ranges. I bet distant orbital path calculations are likely to have multi kilometre-radius errors, making my earlier theoretical area denial tactic even more difficult to implement... unless we're talking kilometres+ wide area denial weapons, in which case YIKES!

If I had to speculate in terms of pK >0.5, I would say that Wedge is right in that we'd see most engagements take place close in; I would speculate that we'd see maximum ranges of about 100,000km (yes, the 1/6,000 mrads means that the ranges would be in low thousands of km, but we're talking way off in the future here where weapon mounts are vastly improved).

So people will see each other long before anyone can do anything effective to each other; and when they start to get close, it will be the ship with the most accurate sensors coupled with the most precise blinding weapon that will win.

Edited September 18, 2015 by Scoundrel