Aircraft carriers in space

[pendell]

Really, really cool essay by a naval analyst who both understands naval warfare and SF. Well worth the read if you're interested in such things.

Respectfully,

Brian P.

[MLai]

I just watched Battleship. So yes, I interested.

[Eric Tolle]

I liked how he pointed out that space warfare wasn't going to be like underwater or air combat.

[Tavar]

Very good article, and points out quite a few important factors in space combat that aren't really addressed by most fiction.

[tensai_oni]

A very good article, and I have a bit more to add. A while back there was a "realistic starship warfare" thread on /m/ (yes, constructive discussion on 4chan, I am shocked too) and here's what was decided on:

-There is no cloaking in space. With our current level of technology we can already detect anything unusual in space that gives off only a little bit of heat, and starships generate A LOT of heat. It's not that we don't have technology that allows stealth yet - physics themselves as we understand them prevents it from occuring. Blame the vacuum.
-Missiles are not an effective weapon. At least, not on very long distances. Acceleration provided by the fuel is insufficient and the fuel itself is a waste of weight and resources. Railguns and energy beams/lasers are the way of the future.
-And of course fighters are a ridiculous idea but the article pointed that out already.

Realistically speaking, space warfare is a battle of glass cannons - everyone can see each other from the start and fire weapons that are extremely deadly and hit nigh-instantly unless we're talking relative distances. As in, distances where theory of relativity starts to matter. For realistically portrayed space combat, conneisseurs* suggest the Honor Harrington books, as well as the anime Starship Operators.

*This is a second hand opinion because I only repeat here what was noted often and agreed on. Unfortunately I am not familiar with the works myself.

[The Glyphstone]

As a firsthand connoisseur, I can say that Weber's HH books are a solid, realistic image of space combat - but for the universe it sits in, and the technology it uses; Weber deliberately designed his physics and tech to bring about the situations he writes, so real-world space combat wouldn't look anything like HH's fleet engagements unless the real world happened to innovate exactly the same technology he created.

That said, they're still good books, and fairly high up on the Mohs Hardness Scale; once the handwave of the technical ability to significantly manipulate gravity fields is accepted, everything else is a logical derivation of that, and aside from the Great Resizing incident, stuff mentioned in that article like acceleration over speed and the need to slow down before you can turn are key elements of warfare in the setting.

[jseah]

You mean, crewed starships generate alot of heat. Robotic ones can be engineered to work at sub-liquid nitro temperatures, which makes detection rather more difficult.

Of course, you still can't hide your starship's engines or your weapons.


And there is the pesky problem that your readers want to read about people and not about Predator drones... in space!
- Although, I am not too sure about this as a truism. *I* certainly would not mind reading a story centering around drone warfare.


EDIT:
Another thing I would expect to see in realistic space warfare is thrusters on *everything*; there are literally no stationary objects. You'll have attitude and station keeping thrusters anyway, so you may as well pack a slightly bigger thruster to improve its survivability by a few orders of magnitude.

Because, due to railguns, anything that cannot accelerate is a sitting duck and can be hit from ridiculously large distances (we're talking interplanetary here for some lasers and purpose built railguns). Even a tiny thruster with only a small emergency reaction mass might save your shipyard.

[pendell]

There is no cloaking in space. With our current level of technology we can already detect anything unusual in space that gives off only a little bit of heat, and starships generate A LOT of heat.

This assumes the solar system continues as it is today, devoid of merchant traffic, outposts, or any dozens of other things. It occurs to me that the problem with space tracking isn't that we don't have visibility, there is just so much of it and so many things. A vehicle moving under constant acceleration is pretty obvious in our night sky the same way a single car would be on a deserted road. But when there are thousands or millions of such objects? A trickier problem.

If I were launching an invasion, perhaps the thing to do would be to build lots of cheap disposable drones with some sort of thermal heat source to imitate powered spacecraft. You couldn't conceal the fact that the bad guys are coming but you could create decoy fleets to bollix the intercept solution, and you could use decoys within the real fleet to get the defenders to waste their shots.

Concealment and misdirection are key to the art of war. Perhaps there are other methods to get the same effect -- to keep the opposition guessing at your intentions until the last possible moment.

Missiles are not an effective weapon. At least, not on very long distances. Acceleration provided by the fuel is insufficient and the fuel itself is a waste of weight and resources. Railguns and energy beams/lasers are the way of the future.

I'm not entirely certain this is true. Given the long distances involved in interstellar warfare it wouldn't take much of a course change on the part of a target to cause a railgun projectile fired from light minutes away to miss completely. This implies the need to close the range to such a distance that evasive action is infeasible, or some mechanism for inflight course correction on the part of the weapon.

-And of course fighters are a ridiculous idea but the article pointed that out already.

Manned fighters are, at any rate.

Another interesting book is The Battle of Sauron . It's not the hardest sf since it allows interstellar drive and deflector shields, but aside from that it has a very good discussion of what interstellar combat and planetary assault would look like.


Respectfully,

Brian P.

[tensai_oni]

I found the article on stealth. Here it is.

If we add in media that are realistic if we include technology/research that changes how we see physics today, as opposed to realistic with today's standards, I can also suggest the Universal Century Gundam series. And of course, Mass Effect.

[Megaduck]

One of the things that I found he and most other writers don't take into account is how hard it would be to find the correct target.

There is no line of sight in space, and you can see everyone. Sounds like a simple battle field, you can see your opponent, they can see you.

Now consider this, there are fifty THOUSAND ships on earth alone. (50,000) These are cargo carries, bulk carriers, and passenger ships and doesn't include smaller privately owned craft.

So assume that a planet with the GDP comparable to Earth is engaged in all out interstellar trade and you are looking at thousands of possible targets.

And you can see every single one.

Figuring out which one is up to no good and which isn't would be like searching a needle in a hay stack and you'd want to be real careful before you hit the fire button.

Now, I'm not saying that that means that it would be suddenly like Pick-your-historical-era but it's a constraint that I've never seen brought up before.

*Edit*
And Pendell brought up a similar point the same time I did.

[Tiki Snakes]

One of the things that I found he and most other writers don't take into account is how hard it would be to find the correct target.

There is no line of sight in space, and you can see everyone. Sounds like a simple battle field, you can see your opponent, they can see you.

Now consider this, there are fifty THOUSAND ships on earth alone. (50,000) These are cargo carries, bulk carriers, and passenger ships and doesn't include smaller privately owned craft.

So assume that a planet with the GDP comparable to Earth is engaged in all out interstellar trade and you are looking at thousands of possible targets.

And you can see every single one.

Figuring out which one is up to no good and which isn't would be like searching a needle in a hay stack and you'd want to be real careful before you hit the fire button.

Now, I'm not saying that that means that it would be suddenly like Pick-your-historical-era but it's a constraint that I've never seen brought up before.

*Edit*
And Pendell brought up a similar point the same time I did.

Alternatively, a ship that far away in space would be really, really tiny. You're not going to notice it with the naked eye or anything. So you're really stuck relying on the ability of your computery bits to find it and recognise it as hostile before it blew to pieces.

[DaedalusMkV]

Perhaps my favorite 'hard'(ish) military sci-fi for depicting scientifically sound space combat is Jack Campbell's Lost Fleet series. Long-ranged attacks are useless because missiles can be easily tracked and either avoided or intercepted and everything else is virtually guaranteed to miss an enemy that's travelling at relativistic speeds while making constant small evasive course-corrections. Since combat is at relativistic speeds, a typical engagement lasts less than a second and is entirely computer-controlled barring human target-priority entries. The speed-of-light communications and sensor gap is in full effect, giving attackers an immense advantage in terms of strategic planning. At one point, the titular fleet has already launched an attack that will destroy all of a solar system's military outposts before they are so much as detected by an enemy unit. Battles take place over hours of realtime and relativistic time dilation is given its proper due.

In short, it's one of the better depictions of the issues built-in to space combat. Not totally hard, of course, since they've got faster-than-light travel, energy shields and some sort of magic inertia-canceller allowing them to accelerate at speeds that would turn a human being into a gooey sludge, but I still really appreciate the attention to detail with regards to the fiddly bits. If real-life space combat ever becomes a thing, I expect we'll see a lot of the tactics and designs from this series come into use, albeit with time-scales in the weeks rather than hours.

[jseah]

I have read Lost Fleet. Have a few quibbles.
The problem with C-fractional speeds is that if your ships can acheive it, so can your missiles.

The primary advantage of relativistic mass drivers and lasers have over missiles is shot speed. (and lack of ammo for lasers, although heat venting becomes a problem) This gets less of a problem when your missiles get closer to that limit.

Also, missiles have mass. Alot of it (more than your mass driver can shoot anyway). At C-fractional speeds, a single impact from even 1 kilogram will hit like a thermonuclear warhead. A 1 ton missile hitting something, even a giant battleship, will utterly destroy it, armour or no. The simple shockwave from the impact will mince everyone in the ship and destroy everything fragile (like electronics that support the ship).
If you can get to 0.7 or 0.8c, it gets even worse, since it hits like antimatter.

With super efficient space drives, every weapon that fires something solid is one-shot-one-kill barring force shields. (mass drivers get to use your ship's velocity)
Hell, their engine fuel has to have such massive energy density that you may as well use it for your warhead barring funky requirements for getting out the energy. 0.1C ships that are ~40% fuel imply a fuel specific energy density around the same as nuclear fusion; unless of course their fuel IS hydrogen and they ARE using nuclear torch drives. But I didn't see any mention of that. (the drive plume can probably be used as a short-range weapon as well)


Also, given the backdrop of the series being some total war scenario, I would not be surprised if their genocidal planet bombardment was actually relativistic rocks.

[t209]

So in reality, space battle would be more effective if it is like Master and Commander (fire eachother with broadside weapons until ship is destroyed)? Except they can maneuever up and down.

[tensai_oni]

@Pendell and Megaduck:

What kind of insane government would let its civilian craft loose when there's a war going on? A hostile ship would just fire indiscriminately at all targets, and it's unlikely it would come in alone, so it's not that it's opening itself up by doing so.

Unless the scenario we have in mind is more of a one-on-one battle, but in the middle of a civilian zone with lots of neutral units, and nobody knows who's who. Which sounds like a pretty exciting scenario for a sci-fi battle of wits and sneakiness, really.

Of course this whole point is rendered moot if we develop detection systems good enough to identify types of units just from their telemetric data/heat signature. Which will probably be the case.

[Johel]

@pendell and Megaduck

Mind you, we are already monitoring millions of objects in orbit of Earth and around the whole solar system.
None of them are actively cooperating with us to help the monitoring.
But we manage to make it work in such a way that anything closer than Jupiter and bigger than a few meters is glowing like a lighthouse on radar.

Space travel would, for detection at least, probably be closer to air travel than naval travel.

Currently, any civilian aircraft is being monitored in real time through various means.
Civilian pilots cooperate with this monitoring because it's in their best interest.
The few who aren't are the ones that know they can avoid detection because... well, we don't have radars covering every inches of the planet.
Not going to technical, it's a lot harder to monitor the sky than it is to monitor the void.

So, all civilian spaceships would be monitored.
And would cooperate with the monitoring in the same way civilian aircrafts do today.
If only because they know they cannot hide and have no intention of being destroyed just for looking too suspicious.

In a given solar system, all objects would identified from the start of a situation.
Any new object suddently appearing in space would look suspect and be probed.
If it is a ship, its point of origin should be easy to figure.
Because all possible launching points in the system would be known.
And no legit settlement would left a ship take off without registering the departure and sharing flight path with other monitoring stations.
Any ship staying for too long in space would be spotted, identified, tagged and followed on the radar as a potential hazard.

Any object of sufficient mass and speed could potentially cause a catastrophic collision.
Any fast new object would be top priority for identification as soon as it would be detected.
And wouldn't be allowed to stay unidentified at less than a billion kilometers of valuable property.
The distance at which an object would need to be identified or pulverised would vary depending of its mass, acceleration and course.

In an interstellar war, the key would be the terms on which the war is being fought.

If each camp think little of torching entire inhabited continents, then it all comes down to being able to get in range before being detected.
Because you don't have to hold ground or even defend.
It's all about making sure no ennemy weapon get in range of your home and that your own weapons get in range of his home.
To destroy any unidentified ships coming close to the "maximum fire range from home" zone would be standard procedure...

If civilian life is of more value, then it can be a bit more complex.

[Ravens_cry]

People still need to eat, factories still need to run. Assuming we ever get to exploiting extraterrestrial resources in a significant way, we are going to have non-military craft operating in space, yes, even during war time. Another assumption is a solar system sufficiently seeded with camera and sensors it wouldn't be possible to redirect the emissions elsewhere. This assumes one knows where the eyes are looking, but if you do, apparently it *is* possible to cloak a satellite.
The precise details are unknown, but since I think we can discount magic.

[Gnoman]

I'm not entirely certain this is true. Given the long distances involved in interstellar warfare it wouldn't take much of a course change on the part of a target to cause a railgun projectile fired from light minutes away to miss completely. This implies the need to close the range to such a distance that evasive action is infeasible, or some mechanism for inflight course correction on the part of the weapon.

The long distances are precisely WHAT makes missles useless. At the velocities needed to fight at long ranges (assuming 1-4 light-minutes here, but this is a problem that increases with distance), you would need a massive amount of thrust to change your course fast enough to adjust tracking. Even with an antimatter-pumped reaction drive, that kind of thrust is not feasible. If you're using a high-output laser, you need only lead the target by about 8 minutes (at 4 light-minutes, you see where the target was 4 minutes ago, and your shot takes 4 minutes to get there), and you don't have to allocate tons of mass on your warship for each shot.

[Johel]

The long distances are precisely WHAT makes missles useless. At the velocities needed to fight at long ranges (assuming 1-4 light-minutes here, but this is a problem that increases with distance), you would need a massive amount of thrust to change your course fast enough to adjust tracking. Even with an antimatter-pumped reaction drive, that kind of thrust is not feasible. If you're using a high-output laser, you need only lead the target by about 8 minutes (at 4 light-minutes, you see where the target was 4 minutes ago, and your shot takes 4 minutes to get there), and you don't have to allocate tons of mass on your warship for each shot.

Well... Depending on the fuel you are using to generate the energy for your laser, you might still have to have tons of mass for each shot...

[Ravens_cry]

At least they can manoeuvre, and respond to real time data as opposed the likely out of date targeting data of a laser on a spacecraft light-seconds or even -minutes away. Also, if the missile and the target are otherwise matched velocities, the energy for a small missile to manoeuvre would be fairly little.
A long thin shaped missile can also avoid at least some point defence by spinning in place on all axis while maintaining a trajectory. The energy that takes is quite minimal.

[Gnoman]

Not on the scale that a missile would require. Assume that you were attempting to deliver a 1-ton kinetic warhead to a target 4 light-minutes away. To hit the target in a reasonable time period, you'd have to get to at least .25c. .5 would be better, but we'll go with .25 for this purpose. Accelerating at 10 gravities (45 m/s/s), it would take 27 minutes to reach that speed. It won't be up to speed when it hits the target, but that's okay, it's still a 1-ton mass at high velocities. This is where it gets impractical. You need to accelerate not only the warhead, but the fuel that is used to shoot it plus the engine that does the accelerating. The amount of fuel required to do so is highly variable depending on the fuel, but a quick Wikipedia check shows the net cost of accelerating the warhead alone in the range of 1000 Petajoules, or roughly 250 megatons. That's the equivalent of the nuclear arsenals of any nation except the US or Russia. IN other words, you'd need massive amounts of fuel, which pushes the energy cost even higher.

[jseah]

It depends on your engine.

Chemical rockets make very lousy missiles.

Fusion Torches starts to get serious.

AM drives can go zoooom and be up in your face practically almost before you know its there.

[Ravens_cry]

It's going to be a while before we are going to have 1/4 c missiles. If that takes a lot of energy for something like a missile, think how much more it would require for something that could be categorized as a spaceship, even flying only 1/8th that.

[DaedalusMkV]

Not on the scale that a missile would require. Assume that you were attempting to deliver a 1-ton kinetic warhead to a target 4 light-minutes away. To hit the target in a reasonable time period, you'd have to get to at least .25c. .5 would be better, but we'll go with .25 for this purpose. Accelerating at 10 gravities (45 m/s/s), it would take 27 minutes to reach that speed. It won't be up to speed when it hits the target, but that's okay, it's still a 1-ton mass at high velocities. This is where it gets impractical. You need to accelerate not only the warhead, but the fuel that is used to shoot it plus the engine that does the accelerating. The amount of fuel required to do so is highly variable depending on the fuel, but a quick Wikipedia check shows the net cost of accelerating the warhead alone in the range of 1000 Petajoules, or roughly 250 megatons. That's the equivalent of the nuclear arsenals of any nation except the US or Russia. IN other words, you'd need massive amounts of fuel, which pushes the energy cost even higher.

Also, as a completely different aside, time-dilation effects and blueshifting at those kind of high C-fractional speeds would make any onboard guidance system all but useless. Figuring out where your target is and where it's going would be at best a game of hedged probabilities, and at worst little more than guesswork, largely negating the purpose of the missile in the first place. Which isn't to say that guided projectiles won't be extremely useful in space combat, because there's very little harm in adding a simple propulsion system to your railgun projectile if you can get away with it and it's not actually that hard to achieve a meaningful vector change on the perpendicular axis. But a cold-launched missile would likely only be useful at short ranges or when the launching ship is already moving at extreme velocity.


Frankly, though, in all reality any real practical space combat would be based around using engine particle streams to destroy your enemy, since almost by definition any proper interstellar engine is going to be far and away more dangerous as a weapon than any actual weapon you could fit on it, what with the whole incredibly deadly stream of ultra-high-energy near speed of light particle thing, not to mention the massive amount of... Mass, saved by not mounting any secondary weapons. Which, in all honesty, doesn't make for a very engaging narrative. "And then we turned the ship around, exposing the enemy to our ion drive. The charged ion stream annihilated their stupid railgun slugs in an instant before reducing their ship to a hunk of molten slag. Morons never even though to turn their own fusion torch on us. Who uses mass drivers as anti-ship weapons, anyways? Everyone knows they only work as bombardment tools, and then only when you want to preserve the biosphere."

[jseah]

Naw, interstellar? Sending people across the stars the slow way (without FTL cheats) is likely to be incredibly expensive and very very very slow. Even at significant fractions of c.

People on spaceships, especially combat spaceships, are something I am coming to think is going to be rather unlikely. Seriously, why do you need to have a crewed freighter? Tanker? Anything apart from space stations?

[The Glyphstone]

Naw, interstellar? Sending people across the stars the slow way (without FTL cheats) is likely to be incredibly expensive and very very very slow. Even at significant fractions of c.

People on spaceships, especially combat spaceships, are something I am coming to think is going to be rather unlikely. Seriously, why do you need to have a crewed freighter? Tanker? Anything apart from space stations?

Redundancy. Unless we somehow develop free-energy and energy-matter replication, transport ships are going to be big and probably expensive. Having a live crewmember or two available just in case the automation fails is reasonable safety measure. This, of course, falls to pieces if you assume we will never find a means of FTL travel; If we don't, it's generation ships, some manner of hibernation, or nothing, and the notion of any sort of consistent interstellar travel, automated or otherwise, is gone...anything or anyone you send into space better be able to take care of itself, because it is for all intent and purpose a one-way trip.

[Ravens_cry]

Maintenance could be one. Things break down and light speed means you can't repair via telepresence unless you are so close you might as well be aboard anyway. You also can't simply write them off as a derelict cargo ship is a hazard. If it breaks up, it creates space debris that are basically a bunch of faster than bullet shrapnel.
If we never invent strong enough AI, a human aboard might be the only option, though this itself adds things that can go wrong.
I'm not saying this is how it would happen, but it could be a justification for story purposes.

[Welf]

Not on the scale that a missile would require. Assume that you were attempting to deliver a 1-ton kinetic warhead to a target 4 light-minutes away. To hit the target in a reasonable time period, you'd have to get to at least .25c. .5 would be better, but we'll go with .25 for this purpose. Accelerating at 10 gravities (45 m/s/s), it would take 27 minutes to reach that speed. It won't be up to speed when it hits the target, but that's okay, it's still a 1-ton mass at high velocities. This is where it gets impractical. You need to accelerate not only the warhead, but the fuel that is used to shoot it plus the engine that does the accelerating. The amount of fuel required to do so is highly variable depending on the fuel, but a quick Wikipedia check shows the net cost of accelerating the warhead alone in the range of 1000 Petajoules, or roughly 250 megatons. That's the equivalent of the nuclear arsenals of any nation except the US or Russia. IN other words, you'd need massive amounts of fuel, which pushes the energy cost even higher.

I make some speculations here: what is a "reasonable amount of time" in space? A few minutes, a few hours or a few days?
If you can accelerate till it's faster than the target, and you can extrapolate it's route, you can let the missile fly quite a time without any further acceleration. And detecting something that has very few energy output is rather hard I think. It's true that in the solar system many objects are well known and mapped, but for that countless observatories with a lot of time are at disposal.
If a missile is provided with a proper AI, it can activate the very last moment and then target the ship. The effect is dependent on how good a ship can watch it's environment. If it always knows where the enemy ship is, and detect all missiles, than it's no problem. If the scanners and sensors can be tricked with fake missiles, or if the computer takes some time to scan the space, then they can work.

[jseah]

But if its going to be a one way trip, whatever you send has to be self-sufficient not just for the trip but indefinitely if you put humans on it. Interstellar human mail is invariably going to be a colonization fleet unless there's a colony on the other end, in which case why are you going there? Unless it's an exploration probe, in which case it's not going to be manned.

If you're going to send repair crews, why not robotic ones? Good AI might be very expensive to develop, but robots don't need air, don't need water, are less susceptible to radiation... you name it.


Warships in particular. AIs can be made to withstand high-g forces and extreme temperature variations (only need to cool the processor). They can pull tighter turns, higher burns, use engines with massive radiation (nuclear salt water rocket anyone? or solid core AM?), have smaller target profile, lower working temperature, go longer with radiators retracted....

And intrasystem freighters are the same.

It's all the same. People are just BAD in space. Whether it is interstellar or just plain Sol system warships, AI run ships are probably massively cheaper, denser and higher performance. Sometimes by an order of magnitude.

[The Glyphstone]

Though at that point, once you've developed those expensive good AIs, they're not only better ship crew, they're better colonists - able to survive harsher climates and environments, more resilient, longer-lasting...why bother shipping out squishy organics at all? For that matter, why bother keeping them around on the home planet instead of rendering them down for raw materials, since the AIs can do everything they can more efficiently?