Which space-based weapon technologies are going to thrive?

Question

Given enough time for research (centuries, basically in a post-faster-than-light-era) and resources, which current (or new) weapon technologies have the most potential?

Missiles? What payload would they use?

Plasma? I know about the problems, but is their potential (damage-wise) worth it?

What about lasers?

I know we are speculating here, but I need to have a logical explanations and specifics for my galactic (human) civilization.

Answer 1

Teacups, floating in space

Well, not exactly teacups, but teacup-sized observation satellites called RTs (for Russell's Teapots Remote Telemetry) will serve as an early warning system. Spaceships' heat signatures in space are very hard to disguise. Of course, a 1-meter probe will have an easier time slipping by than some massive colony ship of a warship armored to resist nuclear impacts. Besides optics, your detectors would use gravitational distortions, if far enough out from massive bodies. Since an object's propulsion jet is visible as well as its speed, you can easily tell the mass, so (accelerated) decoys would not work unless identical in mass to the spaceship you're trying to disguise. This confers an advantage to defense, since they don't need to break or accelerate. Your teacups' sensor grid info could be sent narrowbeam at lightspeed (or darkspeed if you accept FTL and the mess it makes of causality) back to a defense outpost or used to activate some local defenses. Long story short, everyone sees everything you do in space.

Now what would these defenses be? There's an extended discussion of classical kinetics/rockets/beams elsewhere, and you can read that at your leisure.

Fighting through the cracks

My suggestion is rifting. Imagine you have devices with the capacity to bend spacetime itself. Done carefully and with insane levels of precision, this might effectively shorten long journeys, and maybe provide effective FTL spacetime translation. But if all you care about is damage, than a set chaotic, highly unstructured rifts will play havoc with the delicate innards of a ship (such as humans or computers and their minds). Imagine you have "mines" that quietly store all this energy, like a set of corks in a dam. When activated by the teapot sensor, they unplug their carefully designed set of cone-covering spacetime rifts and let it rip the intruding ships apart.

How do you defend against a spacetime distortion? I don't frankly know, but I'm hoping I'll find out about it in the comments.

Answer 2

A key issue here is that you can see and shoot each other from enormous ranges. If you see the enemy at 2AU, you're seeing them where they were 15 minutes ago. Fire a shot at light speed and it won't get there for another 15, so your targeting is 30 minutes out of date. Sensible enemies will be moving unpredictably during this time, so you'll only hit if you get lucky.

Lasers are bad because they hit where our enemy was half an hour ago and they can be reflected. You use a green laser? What a coincidence! The Martian fleet just painted their ships green. You use a tunable laser? Now they've coated them in a metallic layer. Conveniently for them, this is space so it stays perfectly shiny.

Missiles aren't great. Unless they're nuclear or antimatter, the energy from an explosive payload will be dwarfed by the kinetic energy of an equivalent mass traveling at relativistic speeds. We could just use them as kinetic warheads but we won't get much steering at those velocities. Unless we take care of the "we don't know exactly where they are" problem by firing overwhelmingly large AM/nuclear bombs into the general area...

We want to get close to our enemy to shoot them, but we don't want them to get close to us. Sounds like a job for drones. You could have relativistic drones with railguns mounted on them - they can be launched in the general direction of the target and fire their projectiles on approach.

Answer 3

The basic issue is distance. Sensors will tell where the target used to be. Target will have moved evasively before your kinetic weapon or laser reaches it. You drone will be receiving the commands you sent some time ago based what your sensors told about where the target used to be.

So you need to get close enough that the lag is small relative to speed of the ships. FTL weapons and sensors do this. Creating chokepoints at worm holes or compacting combat to planetary orbits does this. Or you can mount your weapon on a missile that has enough sensors and processor power to aim the weapon once it gets close enough to the target you are directing it to.

Note that a drone is essentially a missile that is designed to return and be used repeatedly. If your drives require significant reaction mass or the reusable components are a small portion of the price tag, this is not worth doing. So usually weapons would be missiles, but recon would be done with drones bearing expensive sensor suites. Drones should also be useful for relaying tight beam communications as aiming communication lasers at a moving target is just as difficult as aiming laser weapons.

And what should the missile carry? The greatest energy density comes with a nuclear warhead. Lobbing plain bombs at space ships is not particularly useful as you either need a very large bomb or some way to defeat point defense. Normal solution in fiction is to use the nuke to pump a very powerful X-ray laser. The laser could feasibly have large enough range to have a realistic chance to defeat point defense. Meaning counter-missiles or anti-missile drones would be needed to shoot missiles before they have range.

Alternately you could make the explosion very large and directional so that a larger part of the energy goes toward the target. Essentially this would be a nuclear shotgun. And the way it works it would be kinetic damage from ionized tungsten (or something like it) traveling at ridiculous speed. This might make a good weapon for a counter-missile.

I think that with these weapons defense would have the edge and warfare would concentrate around valuable targets such as planets. There might be extensive minefields around such targets.

Answer 4

Throwing it in a completely different direction (and no idea if this is of interest to you), but in a location where everyone can see everything through sensors long before it approaches weapons range, where computers can target and hit with perfection anything they aim for and where you can project such vast amounts of energy that they can destroy anything, you are not going to see all out combat.

Instead you're much more likely to get mental combat, misdirection, traitors, hacking attempts, and other sorts of subterfuge. The main goal in trying to destroy an enemy vessel will be in outthinking or removing the person in control of that vessel (and potentially any backup they have)

Rather than trying to hide your ship, you would try to either disrupt the enemy sensors (remember: everything they get is sensor input, there is no visual confirmation) or at least get them to think you have disrupted their sensors ("they can't really be coming in at ramming speed! he might be brash, but he's not crazy!").

Rather than trying to shoot a weapon towards them and hoping it hits, you might see a captain shoot a missile in a direction and try to then lure the ship to where it will detonate. ("they launched the MacGuffin towards that other waiting ship! We have to intercept it before they escape with it.")

Ships would come with a variety of weapons, but their use would be heavily improvised. After all; your computer can instantly predict where an incoming weapon will go, how to best avoid it or counter it, and react accordingly. A project traveling at relativistic speed means the opposing computer cannot determine where to shoot. So the computers would heavily cancel each other out.

That means that the options are either outsmarting the computer (which is basically analyzing, hacking or breaking it, most likely from inside the enemy ship by use of a saboteur or traitor) or outsmarting the person issuing commands to the computer in the first place (forcing them to make a bad move that not even a perfect computer can pull them out of)

It does allow for potentially interesting paths, in that there is very limited difference between a military vessel using a relativistic matter accelerator to bombard an enemy ship or a cargo vessel using one of its containers and a hotwired jump-engine to accelerate that to relativistic speed: either will completely obliterate the enemy; it depends on whether the military vessel's captain was lulled into a false sense of security or not whether he'll be able to foresee and evade such a "weapon".

Combat between vessels would be mostly determined by a combination of the best gear and also the smartest, quickest thinking captain and understanding your opponent the best. Large fleets would be rare (too many points of failure) but colorful characters manning ships would be common (because discipline might actually be detrimental, as it is predictable)

Answer 5

One of the most common types of weapons on capital ships would most likely be kinetic energy weapons. Take a dense projectile and launch it at incredible speed, near the speed of light. The impact will release many kilotons of energy, like a nuclear weapon.

Avoids the pitfalls of lasers, aren't as complex as missiles, and keeps everything simple. Missiles would probably be used in shorter range engagements with smaller ships, as mounting something capable of sending an object forward at near light speed would require quite a large ship.