Does anybody know how one would fire a missle in space? I mean, I’ve watched Star Trek and Firefly and a number of other sci-fi epics, and they all seem to have torpedos of some kind, but I have no idea how that would work. I mean, air-to-air missles travel a certain way, and missles fired from submarines travel another way, but how would one fire explosives from one vessel to another in space? And how would they cause damage to another vessel? Don’t they need air or some other kind of medium to ignite? I mean, I remember lasers being used with some frequency, which seems like it’d make more sense, but I can’t quite imagine how the torpedos would work.
All missiles obey Newton’s laws of conservation of momentum: If something is fired very fast, it will continue to go fast in that direction. It can go even faster in that direction by propelling something in the opposite direction.
In space, there is no medium and therefore no friction, and so things will continue in their direction forever (in the absence of gravity) at that speed. So, bullets and shrapnel are just as dangerous and damaging.
However, this lack of medium/friction makes guided missiles are far more difficult to manuevre, just as driving on ice is far more difficult than on a frictional surface. Then, when the missile arrives near its target, the explosion does not propagate a powerful pressure wave like it does in air: even a nuclear bomb is just a very very bright light in space (and a silent one at that).
Lasers would be far more useful weapons in space, since they would not be dispersed by an atmosphere (and, incidentally, would be invisible).
The same way a rocket works. You propel some mass out the back of the missile. The manner that could be used is almost infinite. Chemical, fusion or ion engines would work.
Chemical rockets carry their own oxidizer, while others simply accelerate propellant to high speeds and direct it opposite to teh direction they need to travel,.
However, if you’re wondering about how the explosion intended to damage the target ship would work, you’re right that some explosives require oxygen to work. Traditional explosions are created by the very fast combustion of the explosive, and as anyone who’s watched a fire safety video knows, oxygen is required to do this.
However, the designer of a “space missile” would no doubt take this into account. I am sure someone will be able to provide us with a list of explosives that contain within them the oxygen required to combust. Failing that, some could be transported with the missile (rockets require both fuel and oxygen to be carried with them to work in space, for instance).
Note that nuclear explosions do not require oxygen (although some warheads have a conventional blast first, which might), so nukes could be used in space. Some kind of matter/antimatter warhead could also be used to create a lot of energy, although I believe most of this would be radiation and would not really provide the necessary lethality I think you are looking for.
Of course, when there’s an explosion in the earth’s atmosphere (or under water), a shock wave is transmitted through this medium, and can wreak havoc on things not in the blast radius of the explosion. In space, this wouldn’t happen, so it would be important to get your missile to explode as close to the target ship as possible.
Anyway, why do you think we’ll need missiles in space? Surely all space exploration will be conducted in a friendly, cooperative manner with no rivalry or disputes? Yeah, right.
Why waste all that wonderful kinetic energy you’ve built up getting to the target by simply blowing up? Plow right into it and you’ll convert all the energy into a direct impact.
A slight modification to your statement: the lack of medium doesn’t actually make missles more difficult to maneuver–in fact, the absence of the varying pressure of atmosphere and the drag actually make the calculations somewhat simpler–but it does mean that you can’t use what aerospace engineers and pilots call “control surfaces”. Instead, you have to gymbal the exhaust nozzle, or have smaller attitude jets, or use a gyroscope to pitch, roll, and yaw the nozzle opposite the direction of acceleration.
And stupid, irritating, absurdly pedantic nitpick, but: despite its use in common literature, the term “air friction” has no technical meaning. There is ram pressure, which is what causes heating by re-entering spacecraft, and the lift effect due to Bernoulli’s Principle, but air, being a fluid, can’t actually impart friction (though individual particles in the air can.)
Weeell, it’s a bright light shooting out a bunch o’ high end eeeelectro-maganaetic waves, but the more damage is done by neutron release, which acts like atomic shrapnel (and can irradiate certain materials).
There will be a pressure wave from the actual material of the bomb, but it’ll be a very weak one that will disperse quickly, rather than compressing air into a moving wall the density of steel as it would in atmosphere.
Too true. Only problem is building an energy source with enough power (energy per unit time) and throughput to supply an effective laser. Some work was done on free electron lasers powered by a small nuclear burst for the old SDI 1980’s style death rays, as I recall, but I don’t know that that ever got further than the drawing table.
At short distances or very high velocities (“flat” trajectories), missiles can be line of sight. But for longer distances orbital mechanics comes into play, in which to actually hit a target you have to do some counterintuitive things, like braking to drop into a lower faster orbit, etc.
That’s a good point - a hefty missile could pack quite a punch. However, if you were to equip it with some sort of armour-piercing warhead that explodes once it’s embedded in the target ship, you get the best of both worlds.
I believe modern nukes tend to come with such a warhead - so it penetrates the ground then explodes, imparting more energy to the earth, rather than the big shockwave effect created by the explosions over Japan in 1945.
Or you could just coat your ship in 8 feet of titanium and plough into the other ship at full speed (with your seatbelt on, of course).
Uh, no. Virtually all solid deflagrant (burning, like gunpowder) explosives contain an “oxidizer” as part of their mixture. Here’s a quick reference on rocket engine oxidizers, and here’s a Wiki on oxidizers and reducing agents.
High explosives, like C4 or PETN, operate somewhat differently, in that they undergo “detonation” via a moving pressure wave rather than surface oxidation. (This is why gunpowder is flaked, but plastique explosives are solid. Some explosives, like pure nitroglycerin and its derivatives, are liquid.) There is still a chemical reaction but it’s purely internal, and the reaction occurs at a much higher rate than something like gunpowder or ANFO. (It’s worthwhile to note that some gunpowders, the “double base” kind, can under some conditions detonate. This is not something you want to have happen in a rifle chamber that’s laying four inches from your head, which is one of the reasons why reloaders are so circumspect about making proper measurements.)
Oxygen can be an effective oxidizer, of course, and was the first discovered. (It has currently slipped my mind who discovered this–it’s somebody obvious–but no doubt some well-versed chemist Doper can provide the correct answer.) Pure, and expecially liquid, oxygen can actually be quite dangerous, as it can cause normally reasonably inert items, like the cotton t-shirt you’re wearing, to become highly inflammable, hence the precautions taken around oxygen tanks and so forth.
There’s an apocryphal story about a vat of liquid oxygen, a bored physics grad student, and an overabundence of rats on the UofA campus, but it strikes me as more of a Snopes-worthy story than a likelyhood, so I’ll refrain from reiterating it.
Well, by no means am I a rocket scientist, but it seems to me that you really don’t need big missiles in a space based conflict. Unless your target is halfway across the system and needs specific steering/targeting adjustments (i.e. target is taking evasive action) it seems a cannon or gun of some type would be just as effective and far cheaper.
I mean, because there’s no friction, the projectile maintains all its speed anyway, so it would make sense to build the gun/launcher on your ship, or on a mobile weapons platform, and spend the effort in creating more powerful muzzle velocities and targeting systems. After all, the kinetic enerrgy transferred into the target will be more than enough to destroy or damage most anything it hits, regardless of explosion at the point of impact.
In fact, I would explore things like deployable, manoeverable platforms, as you could control those remotely (protecting the actual ship doing the attacking from being targeted or giving away its position), or set them into a semi-automatic staus, whereby a ring of the platforms secures a region of space. Plus, it’s gotta be cheaper and more effective to lay down a stream of fast moving, unguided projectiles than to launch one or two guided missiles/torpedos. If you spend the effort engineering an efficient and intelligent target acquisition and guidance system, you’ll probably save money & time and be able to deploy more platforms.
I was, of course, making reference to the famous 1920’s New York Times editorial. From what I have seen, their technical understanding hasn’t progressed any since then…
Indeed. Ever see a rail gun? Sandia National Laboratory I think holds the record for propelling an object to something over 35,000 mph. Even a tiny mass (say a gram or two) going that fast will put a big hurt on whatever it hits. Our more mathematically inclined folks can work out how much energy is present in such a thing but I am reasonably certain it would end most any spaceship we can think of building. A rail gun would likey be more useful than a missile in space and I think would do better than a laser as I believe you can get sufficient destructive power out of a rail gun for less energy expenditure than you can out of a laser (on the flip-side it would be harder to hit something with a rail gun than with a laser).
I seem to remember something like this from a Harry Harrison novel; one of the “Deathworld” novels, maybe? (I haven’t read Harrison in years.) Anyway, they had a “rail gun” that just shot out big fields of ball bearings flying at several m/s at the attacking fleet. No dodging, no ducking, no intercepting. Swiss cheese time for the defender.
Yeah, just the differences in orbital velocity between low earth orbit and medium earth orbit is enough to turn a $1B+ satellite into a collection of orbiting scrap. So much for defending satellites from enemy attack, or stationing orbiting nuclear weapon platforms. Stuff is vulnerable out there.
I seem to remember something like this from a Harry Harrison novel; one of the “Deathworld” novels, maybe? (I haven’t read Harrison in years.) Anyway, they had a “rail gun” that just shot out big fields of ball bearings flying at several m/s at the attacking fleet. No dodging, no ducking, no intercepting. Swiss cheese time for the defender.
Yeah, just the differences in orbital velocity between low earth orbit and medium earth orbit is enough to turn a $1B+ satellite into a collection of orbiting scrap. So much for defending satellites from enemy attack, or stationing orbiting nuclear weapon platforms. Stuff is vulnerable out there.
It should be noted that the US actually has a “space” missile (or at least had one). It was an air-launched missile dropped from a plane and then the missile flew itself into space.
