Hard Sci-fi and ship based weapons.

[Knife]

So, I'm ever so slowly developing both a story arc and the universe it is set in. I'm leaning toward a more hard sci-fi setting with only a few handwavium things, namely FTL.

Any way, I'm compiling data on my universe so when I write transit times and dialog about leaving a planet or arriving, I have some what realistic numbers if not jargon.

So I get to weaponry and I'm stuck. If I go with bullets, my ships have to carry the mass of the bullets which if you think of a warship, should be a significant mass and eats into mass ratio. If I go with beam weapon, then I suck up power from somewhere perhaps having another generator of some sort for that weapon, which translates to more mass.

You also get into effects on target. What's more desirable? Lots of tiny holes in a target from high velocity hits from small bits of metal, or burning and cutting large slashes in a hull from an energy weapon?

So, for shits and giggles, if the weapon itself is roughly the same mass for a beam weapon and/or some sort of mass accelerator type gun, which would be best? If it is a beam weapon, what would probably be the best type and it's effects on a target?

And before anyone automatically puts in a link to atomic rocket, been there, done that, want a T-shirt. Didn't solve my problem.

[Coyote]

This may be an interesting spin on it-- depending on how likely combat in space is, anyway. If it is seen as a rare thing to be avoided, then no one wants to schlep around either mostly useless extra generators (beam weapons) or mostly useless rockets & bullets.

So how about this-- beam weapons are run off of batteries, the batteries that normally are needed to help store up excess power for normal ship ops. Beam weapons will deplete those batteries in a hurry, so there are limited shots-- until some wise guy gets the idea to supplement them with solar collectors. Great idea, minimal mass, and useful fo rother applications.

The problem is, solar collectors are easily shot away. So before each combat, you quickly furl your solar sails and tuck them away, and hope you've stored up more energy than the other guy.

Now, of course, you can schlep around extra batteries, but then you're back to the original problem. So that will even out at some golden mean of ideal battery-mass-to-shots ratio.

And, of course, you have the truth that bigger sails means more energy collection, but also take longer to fold up, so again, a golden mean of 'best sail-to-stow speed factor' will develop.

You'll have a sort of old-school ship situation where the sailing ships of old would furl sails (and their colors) in certain patterns best suited for combat, sort of a throw-back to the good ol' days if you want.

Variations can be had-- wealthier nations may have back-up sails, and just go into battle with sails open and not care if they get whittled away, so long as they milk a few more shots out; then, if they win, they just pop out the reserve.

[Minischoles]

You also get into effects on target. What's more desirable? Lots of tiny holes in a target from high velocity hits from small bits of metal, or burning and cutting large slashes in a hull from an energy weapon?

Well with a large slash in a hull it doesn't really do much damage to the systems, i'd imagine what it would be mainly useful for would be explosively decompressing the ship and trying to get the atmosphere to vent out. But then if its a military ship you'd have to assume they'd have worked some protection around this (deadlocked bulkheads during combat, or even fighting in space suits and draining their own atmosphere in battle to actively prevent an explosive decompression killing their crew).
I'd go for the small high velocity projectiles if you could, accelerate something fast enough and you could do a fair bit of damage to an enemy ship, but then you run into the power generation problem in that to accelerate to high velocity you need extra generators. Maybe have military grade ships or any that mount weapon carry extra generators they can bring online during a battle, or some kind of overcharge ability for them to run 'hot' for a short time to fight.

[GrandMasterTerwynn]

So, I'm ever so slowly developing both a story arc and the universe it is set in. I'm leaning toward a more hard sci-fi setting with only a few handwavium things, namely FTL.

Any way, I'm compiling data on my universe so when I write transit times and dialog about leaving a planet or arriving, I have some what realistic numbers if not jargon.

So I get to weaponry and I'm stuck. If I go with bullets, my ships have to carry the mass of the bullets which if you think of a warship, should be a significant mass and eats into mass ratio. If I go with beam weapon, then I suck up power from somewhere perhaps having another generator of some sort for that weapon, which translates to more mass.

And don't forget radiators to dispose of all the waste heat your beam weapon will generate. TNSTAAFL, after all. Though if you've got FTL, then you might not have a power generation problem, as the energy expenditure needed to move a spaceship interstellar distances ought to be quite a few orders of magnitude more than what you'd need to convert the whole mess into incandescent vapor.

You also get into effects on target. What's more desirable? Lots of tiny holes in a target from high velocity hits from small bits of metal, or burning and cutting large slashes in a hull from an energy weapon?

Actually, the small bits of metal will vaporize upon impact, and the vapor will spread out, punching out cone-shaped holes in things as the impactor deposits its KE into the target. And a beam weapon will either poke tiny holes in the hull, or swaths of melted areas, depending on dwell time of the beam, beam power, and distance to target. The principle advantage of a laser is lack of travel time, but you need to use a high-powered laser out at the far UV end of the spectrum if you want any real range out of it.

So, for shits and giggles, if the weapon itself is roughly the same mass for a beam weapon and/or some sort of mass accelerator type gun, which would be best? If it is a beam weapon, what would probably be the best type and it's effects on a target?

For identically low masses . . . well, the gun would probably be a better pick. You could even build smart "shells" with just enough delta-V for minor course adjustments to shoot out of it. Granted, a laser system of identical mass would be sufficient to shoot down your shells, but this is why you spam your opponent with a broadside and hope there's not enough of him left after it arrives.

If you go up in size and mass, you've got more mass to devote to radiators and optical trains, making for a longer-ranged laser that might be useful for something other than point-defense.

[Darth Raptor]

Yes, extra mass is a problem, but it has an "easier" (not cheaper) workaround than beam weapons, that being extra thrust. To make anti-ship lasers practical, you'll need to handwave the heat away as huge radiator wings aren't the kind of thing you want on a warship. That's the crux of the problem: To get the kind of power comparable to nukes or kinetic kill projectiles, you'll need laser cannons that are really more like blast furnaces that produce coherent light as a byproduct. Without a technomagical means of dumping that heat (PS convection and conduction don't work in space, radiation is your only option) you'll get nowhere fast.

Lasers are great for point defense, but your anti-ship weapons will be nukes and kinetic kill projectiles.

[Ted C]

Before deciding on what weapons are best, decide what it takes to destroy one of the ships. If the ships are pretty fragile, you won't need an extremely powerful weapon. If the ships are extremely hard targets, you need something more substantial. I tend to think that in pretty hard sci-fi, ships will be pretty soft targets. It really doesn't take all that much damage to disable a modern jet fighter or bomber, and modern spaceship designs are even more fragile.

I would lean toward beams over unguided projectiles, since beams will travel at lightspeed to the target, which could be significant in space battles. The other alternative would be guided missiles of some sort.

My own gut feeling is that victory will often be dictated by who can detect and attack first, retreating out of range before the enemy can return fire. Various people on the forum, though, have indicated that starships ought to be pretty easy to detect, so it might really just devolve down to which side has the greatest effective range.

[Tasoth]

Why not leave it at point defense weapons to ward off missiles from the surface and set up some form of cable tow assembly to drag asteroids with and drop on a planet?

[Knife]

Hmm, maybe some background will help since there are a lot of varibles when it comes to these sort of things.

For the most part, the only handwavium I'm using is FTL. Kind of a warp/fold type thing from good old Legrange points or what ever.

Past that, I'm thinking of AM beam rockets as a standard engine for my 'good guys' with artificial gravity being acceleration/deceleration and perhaps internal rotating decks on some of the larger ships.

Warfare would be between exit points in the system to the target planet by cruiser/destroyer type vessels that are little more than a large screen for large landers that deploy huge armies. My good guys, and hell bad guys are galactic players so invading a planet is a endeaver that needs thousands of ships and millions of troops on the first wave. Millions die on small skirmishes, thousands die with just one ship being destroyed. That kind of thing.

I can see my armada's coming into 'realspace' and having their exhaust aimed at the planet for deceleration. This gives 'gravity' in the ships while they decelerate, and also a down and dirty 'weapon' coming into orbit with a high velocity m/am plasma beam shooting out the back. (powerful engines are weapons after all).

It's at this point I'm stuck. Shooting bullets up to an approaching ship with such thrust seems futile so you'd have to wait till they decelerated and reoriented for combat to shoot at them. So beam weapons make sense here.

However, with such combat, you'd go want to spam the area with lots of weapons so slug throwers make some sense. Plus dual use on the planet for the 'assualt ships'. Would also decrease the mass after shooting off thousands or milions of rounds, for take off or return trips. Planetary weapons for the ground forces are bullets and rockets and such, man packed beam weapons being too large and unweildy, mainly power source. But that wouldn't stop a larger ship from having the power.

I account for heat too, since it's a am reaction and plasma engine, perhaps with added hydrogen ejecta as an after burner type thing. All ships would need huge radiators, perhaps a bit of unobtainium there, large ring like radiators around the engines.

[Mr Bean]

Honorverse has this right. Beam weapons are possible with old style bomb-pumped nukes. You load up a missile with a nuke and and a beam-projector. Missile flies towards target, once it gets in range nuke goes off, projector uses heat to fire beam at enemy ship before nuke destroys it and you get a weapon with a stand-off range.

Pretty much look at what David Weber has done with missile technology but minus Imperliers so you have what drive system you use, beam via bomb pumped nukes, and failing that simple nukes will do a number on any ship they hit, and even if they miss, if they have a decent promixity fuse you still might get a chunk of the enemy ship.

[Ender]

The big question here is what is your acceleration? Higher accels demand increased weapon velocity. Compare the recoil with your ships mass and the required energy to accelerate it with the energy demands for your lasers. At a certain point lasers become superior. Further, in a hardish space opera, range is your best defense. Again, the further out the target is, the more important your weapons velocity is. An X-ray or grazer will do a nice amount of damage with minimum dispersal.


Of course, the real question is if you have FTL, why do you not have FTL weapons? Afterall, you need FTL sensors to see where you are going with your FTL drive, so you can clearly send an FTL signal. Raise the power of the signal and burn through the target instead of pinging it.

[Junghalli]

I wrote an essay on realistic space combat on SB a while back that you might find interesting.

Here you go.

Long story short I think the weapons of choice would probably be missiles and lasers (or possibly particle beams). Guns probably wouldn't be used much because unless you had truly ridiculous muzzle velocities they'd be very short-range compared to the scale of distances in space. Missiles would probably not need warheads: at the kind of speeds spacecraft capable of crossing a solar system in a reasonable time would be zipping around at a missile will usually have tremendous kinetic energy behind it.

[Mr Bean]

Nukes are expensive overkill; I don't see any need for them. The kinetic energy of your bullets punching through the other guy's equipment will probably still get you the kills you want. The other ship probably won't be vaporized, but he won't be a threat anymore either.

Massive overkill?
Did you just use the phrase massive overkill when describing space battles?
First off, why are does massive overkill matter? This is space, IE an empty void. If you miss your enemy with a bullet it does nothing if you miss your enemy with a nuke you still might get a piece of him.

Second range
At two hundred and fifty miles away miles your going to have serious issues hitting a dodging space ship with something like an A-10's 30mm cannon. At two thousand miles ensure a hit on a dodging space ship requires rail or coil guns firing very fast projectiles. At one hundred thousand miles even with rail guns unless you have .5C + speed good luck hitting them with bullets.

Meanwhile a missile over-comes that advantage(As does Lasers which are C to begin with) extending effective engagement ranges all the way out to 180,000 miles with instant hit weapons, and missiles can move to hit a fleeing or dodging target.

As noted space is three dimensional making dodging much easier, and the first hit in combat will likley result in a kill unless you start tossing in super-advanced materials in ship construction.

So lets recap

Laser(and Particle beams) are instant hit anywhere under 100,000 miles zone(Gotta leave fuzz room because even a second is a long time)

At that range bullets are next to useless as even slight course changes result in them missing by over a hundred miles by the time they fly by.

Missiles(with nuke war-heads) make great weapons as they can "soft-kill" a ship even if they miss and even a ship made of the most heavily armored material know to man will crunch like a toy if a nuke gets a direct hit.

They even work on warships: solar panels are big targets, but resistant to damage. If your nuclear reactor gets a hole punched through it, you'll probably have to shut it down. If a solar panel gets a hole punched through it, it gives less power, but the rest of the system still works; it is decentralized. Furthermore, solar panels can have their own radiators built-in, removing another potential enemy target.

Unless your enemy is firing nukes instead of bullets at you in, which case your solar panels provide massive weak points.

[SylasGaunt]

So I get to weaponry and I'm stuck. If I go with bullets, my ships have to carry the mass of the bullets which if you think of a warship, should be a significant mass and eats into mass ratio. If I go with beam weapon, then I suck up power from somewhere perhaps having another generator of some sort for that weapon, which translates to more mass.

Don't forget that old saying 'Speed kills'. In space a lot of the limits imposed on low mass/high velocity projectiles go away. Plus if you're firing in line with your ship you get the additional velocity of your ship + the mass driver behind the projectile.

Then there's the issues of Kinetic vs. Thermal damage and quite frankly right now kinetic strikes give you a lot better damage for energy spent most of the time.

[Junghalli]

Massive overkill?
Did you just use the phrase massive overkill when describing space battles?
First off, why are does massive overkill matter? This is space, IE an empty void. If you miss your enemy with a bullet it does nothing if you miss your enemy with a nuke you still might get a piece of him.

I think he was more thinking of the fact that there's no reason the missile needs a warhead and there are disadvantages in having one. A missile with a warhead is more massive, meaning you can't carry as many.

I don't think "missing" is a serious issue. There's no stealth in space; your target is going to be emitting tons of energy. Combine this with the advanced computer systems a spacefaring society would have and the missiles will be basically aim-bots: the only way they could miss is if you outran them. The main problem is going to be point defense lasers, which with mature laser tech and aforementioned targeting should be very effective in the no-stealth environment of space. You're probably going to have to bury the target under hundreds of missiles and hope that one of them survives long enough to actually hit. Obviously, this means you want to be able to carry as many missiles as possible.

I don't think a nuke would really be much more effective, because with the distances and speeds involved in a space battle the difference between exploding 50 meters away from the enemy ship and physically hitting it is negligeable. The nuke will do its damage maybe a fraction of a second earlier than a direct hit at best; the odds of that making any difference in whether the missile survives or not are very low. Whereas if you use KE impactors you can probably throw more missiles.

As for solar panels vs. onboard reactors, something to keep in mind is that solar panels don't work very well in the outer system. A ship that uses solar panels for power will be restricted to operating close to the sun.

[Mr Bean]

Don't forget that old saying 'Speed kills'. In space a lot of the limits imposed on low mass/high velocity projectiles go away. Plus if you're firing in line with your ship you get the additional velocity of your ship + the mass driver behind the projectile.

Then there's the issues of Kinetic vs. Thermal damage and quite frankly right now kinetic strikes give you a lot better damage for energy spent most of the time.

Again I'm going to keep cracking down on this, it's engagement range.

Why don't ships fight each other 2,000 miles away? Curve of the earth makes it impossible.

How about space? A vast empty void? Heck if we today wanted to send up with moon orbital style craft with a cannon of some kind, we today possess the sensors and radar's necessary to fight engagements at ten thousand miles. A Laser at that range is an instant hit weapon, but a modern rail gun fires at just 2.4 miles/second. It won't slow down much in space but conisder the fact it will be thirteen minutes between when you fire the gun and when the projectile arrives.

In that time, a one cm/sec drift in any direction will result in your projectile missing by miles some thirteen minutes later when your rail arrives.

I'll repeat that again, today with OUR technology if we wanted to put two space-craft into deep space, it would be possible with 2008 sensor technology to fight at ranges exceeding two thousand miles. With the best super-fast rail gun in existence today at those ranges it would take minutes between firing your unguided projectiles and when you would hit.

Be serious people bullets in space are useless, the ranges are simply to great to make any non-guided or C weapons useful. And FYI if you put little motor's on bullets to make them self guiding guess what? It's a missile now, might as well simply build it as a missile to begin with.

[Mr Bean]

A nuke is also expensive: uranium is probably very rare in space. You can import it from planets, but that still implies a high cost. Of course, if your setting has lots of planets and lots of ground to space transportation anyway, it might not matter.

The US alone has enough nuclear material today to build a couple hundred gigatons worth of nuclear weapons if we wished, we used to have that much back in the fifities. Smaller nukes take more material as Sheppard has demonstrated in the past, but it does not take all that much material for a one hundred kiloton nuke which has a two mile lethal zone against all know materials and a four mile lethal zone against anything not made of two feet of solid reinforced titanium.

Something that is cheaper than a nuke while still being able to get a kill if it misses: a fragmentation missile.

Except as noted a nuclear missile can be much much more powerful for the size

Remember this little baby?

Davy Crockett, the closest we ever got to a MANPAD nuke. With a yield up to .5 Kiltons(That's 500 tons of conventional explosives) and a lethal range at almost half a mile.

Any idea how big you'd have to make a conventional frag-missile to equal that zone of death? I'll tell you, a MANPAD rocket that size is lucky to have a ninety meter kill zone, let alone a 900 meter zone like the Crocket could.

It flies in, then explodes at some distance, spraying thousands of little balls into the area of the enemy, which spread out to cover more volume than a simple kinetic kill vehicle.

It isn't omnidirectional like the nuke, but should still be able to score kills with misses - the kinetic energy of the balls could be high enough that just a few of them can ruin the target's day.

Again it would have to be much bigger which costs you in fuel and possible interception than a nuke would.

Nukes are so highly useful in space for a reason, you can cram so much more pound for pound destructive ability than anything else sans Anti-matter.

Unless your enemy is firing nukes instead of bullets at you in, which case your solar panels provide massive weak points.

If the enemy is firing nukes and it is close enough to destroy your panels, it will probably destroy (or seriously damage) the rest of your ship too. Then again, they might be more vulnerable to the radiation the nuke shoots its way than the body of the ship. Still, if you lose them, you can still fight off batteries for a while.[/quote]

Yes but your done, your ship can no longer fight, and will of course soon die, the other ship has the simple option to pull away and let you die since you can no longer go charging after them.

More to the point as noted elsewhere, your solar panels restriction your operations zone.

[Sea Skimmer]

Radiators should not be that horrific a problem. Design the ship like a submarine, long and tubular. At one end of the tube would be a huge multilayer system of bulkheads and armor for protection, which is pointed at the enemy and which extends slightly beyond the edges of the hull to provide a wider ‘shadow’ of protection for the hull. The other end would have the engines. This takes advantage of the fact that the orientation of a ship and its actual direction of travel are not linked, unless you do a main engine burn your course wont be changed by spinning the ship around with thrusters, so unless you need to change course you can always keep that one big piece of armor pointed at the enemy. This would be more practical then trying to armor the entire ship to a worthwhile degree. Robotic arms or folding masts or whatever, could be used to move sensors and weapons beyond the edge of the this armor shield when needed, snapping back against the hull when enemy weapons get close.

Meanwhile all the surface area of the long tubular hull can now be covered in radiators which are relatively well protected. A water jacket inside a double hull could be used as armor (well, mainly radiation protection, radiation spikes unlike enemy weapons may come from any direction without much warning), as a heat sink to handle peak loads and to supply various ships needs. Potentially you could have additional telescoping radiators that are extended when needed, I’ve seen this proposed by NASA for a nuclear powered ion drive probe.

A nuke is also expensive: uranium is probably very rare in space. You can import it from planets, but that still implies a high cost. Of course, if your setting has lots of planets and lots of ground to space transportation anyway, it might not matter.

If you can even THINK about building a spacegoing warship that can leave orbit the cost of a mere nuclear bomb with maybe 20-50 pounds of uranium in it is going to be utterly irrelevant from standpoint of cost and raw industrial effort required. The craft is already going to have to be nuclear powered anyway.

[MichaelFerrariF1]

Railgun shells can be solid, as opposed to carrying explosives, because of their kinetic energy. If your ships have multiple and/or rapid firing railguns, you could "spray and pray" while opposing ships close to more accurate ranges.

In a scifi story I'm writing, different weapons are used for different ranges.

At extreme long range to close range, missiles are used.

At long to medium range, large fixed railguns running the length of the ship are used.

At close range, most ships can no longer turn to point at each other, so turret mounted railguns are used.

At point blank range (a kilometer or less), ship to ship missiles have reached the edge of their maneuvering capability, so turret railguns are used exclusively.

Energy weapons are used exclusively for point defense in shooting down missiles.

If you plan on including fighters, I can give a few ideas for fighter based weapons as well.

[Junghalli]

Davy Crockett, the closest we ever got to a MANPAD nuke. With a yield up to .5 Kiltons(That's 500 tons of conventional explosives) and a lethal range at almost half a mile.

Any idea how big you'd have to make a conventional frag-missile to equal that zone of death? I'll tell you, a MANPAD rocket that size is lucky to have a ninety meter kill zone, let alone a 900 meter zone like the Crocket could.

Remember that nukes are a lot less effective at damaging structures in space, because there's no shockwave. You have to rely on radiation to do damage, and even there a spacecraft, especially a warship, is probably going to be a good bit tougher in terms of how much heat it can take than an exposed human. That half mile effective radius may be a lot less if you're planning to use it against spacecraft.

Railgun shells can be solid, as opposed to carrying explosives, because of their kinetic energy. If your ships have multiple and/or rapid firing railguns, you could "spray and pray" while opposing ships close to more accurate ranges.

I really don't think "spray and pray" is going to be effective in space warfare. Your semi-random spray of munitions is going to be pretty dispersed by the time it gets to the enemy ship tens of thousands of kilometers away.

[SylasGaunt]

Again I'm going to keep cracking down on this, it's engagement range.

Except he hasn't told us what distances his ships engage at.

How about space? A vast empty void? Heck if we today wanted to send up with moon orbital style craft with a cannon of some kind, we today possess the sensors and radar's necessary to fight engagements at ten thousand miles.

A Laser at that range is an instant hit weapon, but a modern rail gun fires at just 2.4 miles/second. It won't slow down much in space but conisder the fact it will be thirteen minutes between when you fire the gun and when the projectile arrives.

In that time, a one cm/sec drift in any direction will result in your projectile missing by miles some thirteen minutes later when your rail arrives.

Except that there an enormous number of factors that influence this and it's effectiveness. First of all it's pretty much useless without knowing how fast ships can change direction and what speeds they can accelerate their rounds to. How much armor do they have? What's the approach angle? Can the gun fire fast enough to limit the enemies maneuvering options? Does the bullet carry any sort of warhead? What kind of thermal/kinetic resistance does their armor have? How fast can they throw a railgun shell? How good is their laser focusing? How visible are the rounds on incoming sensors? How good is their tracking software at generating a firing solution? How fast is the firing ship going?

I'm not arguing that a projectile weapon is going to have a longer accurate range than a laser.

I'll repeat that again, today with OUR technology if we wanted to put two space-craft into deep space, it would be possible with 2008 sensor technology to fight at ranges exceeding two thousand miles. With the best super-fast rail gun in existence today at those ranges it would take minutes between firing your unguided projectiles and when you would hit.

And with the best laser we have today how much damage could we do at that range?

Be serious people bullets in space are useless, the ranges are simply to great to make any non-guided or C weapons useful. And FYI if you put little motor's on bullets to make them self guiding guess what? It's a missile now, might as well simply build it as a missile to begin with.

And what about the issues of missiles in space? This all assumes after all his drive can be miniaturized sufficiently, carry sufficient propellant both for the trip and any adjustments in course, and still be cheap enough to be expendable.

[SylasGaunt]

Railguns also have the whole planetary bombardment thing going for them. If your projectiles are tough enough to survive high-speed re-entry you could lob the things at the planet in question from across the solar system.

[Mr Bean]

Remember that nukes are a lot less effective at damaging structures in space, because there's no shockwave. You have to rely on radiation to do damage, and even there a spacecraft, especially a warship, is probably going to be a good bit tougher in terms of how much heat it can take than an exposed human. That half mile effective radius may be a lot less if you're planning to use it against spacecraft.

Again that half mile range refers to the thermal flash zone on earth where people are literately turned into ash. In space this radition is increased because there's no shock wave. Claming a half mile destruction zone when in RL a one point six mile zone of destruction was recored in Hiroshima when a 16kt nuke was dropped on it is not beyond the bounds of reason for my hypothetical 10kilton nuke.


However again, the primary usefulness of nukes in space is again, the bomb-pumped Laser. Mate a nuclear bomb to a missile body with a sheet of single user graser/laser firing apparatus. Get twenty thousand miles away from your target, nuke explodes and hopefully the missile is aimed in the correct direction the nukes energy is converted it to horribly powerful X-Ray lasers which are instant(Ten milliseconds to be exact) later the stupidly powerful rays slam into your target turning it into scrap.

What's better you can hedgehog 180* degree arch of the missile body to fire to increase your chances of hitting since the nuke is acting as a stand-off missile. Unlike KKV's which must contact the target to do damage


Lookie here

That's what I mean by hedgehog, multiple very powerful lasers powered by the detonation of a nuke in space which as you noted pumps much more into radiation because it has no shockwave. All you need do is provide the correct concentration guides to turn that into a highly lethal weapon.

[Mr Bean]

Railguns also have the whole planetary bombardment thing going for them. If your projectiles are tough enough to survive high-speed re-entry you could lob the things at the planet in question from across the solar system.

Why not use the systems astroid belt and slap an engine on any handy chunk of rock? It's not like you need to use your own.

[SpacedTeddyBear]

For weapons mounted on capital ships, I'd go with a high powered diode pumped YAG laser for CW operation. The pump source has a fairly good electrical->optical efficiency, and the narrow bandwidth of diodes allow it to pump directly into the transition range of the gain medium without energy waste into other spectra. A couple of kinetic weapons for simple point defense would be mounted near vital areas of the ship. Or even have a bunch of rocket launchers to missile spam a vicinity of smaller enemy ships on intercept course. They probably won't hit em, but it will cause them to break formation.

[Junghalli]

And what about the issues of missiles in space? This all assumes after all his drive can be miniaturized sufficiently, carry sufficient propellant both for the trip and any adjustments in course, and still be cheap enough to be expendable.

Realistically, missiles would likely be using chemical rockets, because nuclear doesn't scale down well. They'd have higher accelerations than the nuclear rocket powered ships, but lower delta Vs, so they'd have a definite range limitation, though exactly what it would be depends on the precise speed and orientation of the opposing ships and what acceleration they're capable of.