Discussion: Projectile weapons in space

[Rafael]

I have an SF project in the oven  and it includes the use of guns and cannons for outer space use. Of course, mine will be gauss/rail guns, but the thing that nags at me is the nature of the projectile's loads. There will be, of course, KE and "grape" shots. But the ones I can't figure out are the explosive ones. In my backstory, explosive ordnance carry their own oxidizer/combustible mixed in so whiffingly speaking I have it covered by this little physics laws warping.

Have any of you seen/dreamed/invented anything like this ones?

Oh! and check Orionblamblam's Orion's thread, with an interesting cannon/gun armed "space cruiser" concept: http://www.whatifmodelers.com/index.php/topic,22882.msg330513.html#msg330513

Rafa

[Spey_Phantom]

well, as far as a sci-fi build, i always had a feeling of a militarised version of the space shuttle, equiped with an ASAT laser, deployable laser satellites and EMP Torpedo's & spacemines 

(EPM = ElectroMagnetic Pulse, as these can fry an enemy satellite, shuttle or space station's electronics, making it unable to fight )

[Ed S]

Rafa, existing guns and explosive shells would work just fine in space.  They don't require any atmospheric oxygen both the shell and the propellant are completely self contained explosive and oxidizer.  The only problem is making sure that the trajectory is thought out.  You wouldn't want to fire an explosive shell that missed the target and then orbited back around the planet and hit you an hour or so later.

Ed

[CanisD]

http://www.projectrho.com/rocket/index.html
Good site for info on real space combat.

[pyro-manic]

The other problem is recoil, of course.

The Russians built an experimental armed satellite, which was equipped with a 37mm cannon IIRC.

EDIT: http://en.wikipedia.org/wiki/Almaz

Regarding projectile loads, I think a fragmentation warhead would be best - it's very hard to armour space vehicles, because of the weight involved, so a frag load with a slight delay on the fuse would be ideal.

[Ed S]

The other problem is recoil, of course.

The Russians built an experimental armed satellite, which was equipped with a 37mm cannon IIRC.

EDIT: http://en.wikipedia.org/wiki/Almaz

Regarding projectile loads, I think a fragmentation warhead would be best - it's very hard to armour space vehicles, because of the weight involved, so a frag load with a slight delay on the fuse would be ideal.

Or lots of small KE penetrators (i.e. shotgun blasts).

Ed

[MihoshiK]

I have an SF project in the oven  and it includes the use of guns and cannons for outer space use. Of course, mine will be gauss/rail guns, but the thing that nags at me is the nature of the projectile's loads. There will be, of course, KE and "grape" shots. But the ones I can't figure out are the explosive ones. In my backstory, explosive ordnance carry their own oxidizer/combustible mixed in so whiffingly speaking I have it covered by this little physics laws warping.

Have any of you seen/dreamed/invented anything like this ones?

Oh! and check Orionblamblam's Orion's thread, with an interesting cannon/gun armed "space cruiser" concept: http://www.whatifmodelers.com/index.php/topic,22882.msg330513.html#msg330513

Rafa

Frankly, don't bother with normal explosives. With the speeds required for space combat any projectile (at 3 km/sec and over) will carry as much or more kinetic energy than it's own weight in TNT. That's right, fire that slug at 3000 meters per second and it will have roughly the same amount of kinetic energy as a similar mass of TNT has in explosive power. Except that that slug will give off ALL of it's power into the target, and not in a dissipating bang.
If you want to use explosives in you gun or missile projectiles, the only realistic choise is nuclear ones.

And if you want to keep it realistic, you absolutely HAVE to check out the following site:

http://www.projectrho.com/rocket/index.html

and for weapons:

http://www.projectrho.com/rocket/rocket3x.html

Aaand I saw that CanisD was way ahead of me. Ah well.

[tinlail]

Well you might find having radar fused shells like anti-aircraft gun did in WWII to be useful, it would allow a near miss to still damage the target. One factor you may want to explore is the hazardous waste of a battle, i.e. all the fragments flying around afterward. One could defeat the enemy in orbit, and still not be able to stay there because of all the flying bits. An extended battle might make simply being in orbit as dangerous as enemy, or both side might have to flee the area.

[Rafael]

I see now the advantage of KE. But, if pyrotechnics work well in vacuum, explosives would be usable too, for example, in HEAT or SQUASH warheads, delivering whatever energy they yield solely on the point of impact, since now I understand that vacuum doesn't transmit a blast's wave front, so a purely explosive warhead wouldn't make sense.

Rafa

[Jeffry Fontaine]

I have an SF project in the oven  and it includes the use of guns and cannons for outer space use. Of course, mine will be gauss/rail guns, but the thing that nags at me is the nature of the projectile's loads. There will be, of course, KE and "grape" shots. But the ones I can't figure out are the explosive ones. In my backstory, explosive ordnance carry their own oxidizer/combustible mixed in so whiffingly speaking I have it covered by this little physics laws warping.

Have any of you seen/dreamed/invented anything like this ones?

Oh! and check Orionblamblam's Orion's thread, with an interesting cannon/gun armed "space cruiser" concept: http://www.whatifmodelers.com/index.php/topic,22882.msg330513.html#msg330513

Scott's use of the Navy's Mk42 5.0"/127mm gun turrets on that drawing caught my eye when I looked at his work yesterday.  I figured it was a novel way of adding firepower to a space vehicle but the physics involved with handling the recoil would be interesting. 

I recall reading a science fiction novel many years ago where the 12 pound cannon ball proved to be the ideal weapon and they were launched by some kind of electro-magnetic rail gun device with great effect.  The idea of an archaic cannonball being used in modern warfare to defeat an enemy in the vacuum of space was something that sparked the imagination.  I think that same novel also described a matter transport device that was also used to beam explosive charges into the enemy vessels before detonation which was done to get around the energy shields if I remember correctly. 

[MihoshiK]

I see now the advantage of KE. But, if pyrotechnics work well in vacuum, explosives would be usable too, for example, in HEAT or SQUASH warheads, delivering whatever energy they yield solely on the point of impact, since now I understand that vacuum doesn't transmit a blast's wave front, so a purely explosive warhead wouldn't make sense.

Rafa

Again, why bother? With any realistic railgun or coilgun speeds you're already matching or overmatching any mere chemical energy reaction from explosives. Remember, 3 km/sec is piddling in any kind of ranged space combat.
Seriously, the only explosives worth a damn in space combat are burst charges, to allow a kinetic projectile to break up into a nice shotgun swarm, or nuclear ones. And even the nuclear ones will have to go off quite closely for them to do serious damage, but at least they will do damage in proximity explosions.

[Rafael]

Agreed.

Now, I envisioned my spaceship having a spinal-mount BFG for front-quarters-only, heavy fire. I can load everything like the above for long-range, Capital-ship engagements. But, what about orbital bombardment? besides a Rods-from-God pod attached, I would like to have said BFG also capable of striking sub-and surface targets from orbit. Any ideas?

Rafa

[Hobbes]

Frankly, don't bother with normal explosives. With the speeds required for space combat any projectile (at 3 km/sec and over) will carry as much or more kinetic energy than it's own weight in TNT.

If one side can fire projectiles at 3 km/s, the other side will probably have enough engine power to evade a gunshot. I think it's inevitable to use (powered and maneuverable) missiles instead. That also mitigates the problem of recoil (which would be significant on a 3 km/s projectile). 

[Rafael]

I believe that using terminally guided projectiles could be a solution, then, at least for medium-to-heavy projectiles. A sweet solution for mid-to-long range shots, where the endgame situation requires boost or vector change to adjust for drift or maneuvering of the target vessel.

Also, we're talking of gauss/railguns here. Will recoil be negligible in these kinds of weapons, assuming a very, very, very high muzzle speed and G-acceleration imparted to the mass fired?.

If any, would a coordination with flight control systems aboard be a solution, ie.: firing thrusters/grav pulses to keep station?

Rafa

[Hobbes]

Any weapon that transfers energy to a projectile will have recoil, doesn't matter if it uses a powder charge or a magnetic field. Newton's third law applies (action=reaction).

A flight control system can compensate of course provided you have enough fuel.