Thread: The use of cannons in space?

Cannons, guns are tabbo in space, apparently the recoil can be so disruptive that it is not ideal to have cannons or guns on a space craft (mostly due to the recoil in zero g), but lets say you have a turret mounted on a ship with a lot of micro thrusters sensors all the important stuff.
I mean in space whats wrong with wondering a few hundred meters firing a cannon at a enemy ship? Would you even wonder off that far even under sustained fire whats so bad flying off milles away. I mean these ships should be alble to correct for wondering off, and even if it wonders off I'm sure that the battle would probobly be moving every where and not stay in the same place in space.


I questioned this well watching a episode of Modern Marvels I think it was the episode Extreme aircraft II I could be wrong though. There was a simulation of the first space aircraft engaged in combat against another nation. They envisioned Ramjets flying in to orbit the Jets were were not able to stay in space, they had no micro thrusters and could not maneuver. They skipped in and out of atmosphere, they had no other weapons besides a single turret laser mounted underneath the aircraft, it said that conventional weapons would not be ideal in space, and that in the future spacecraft would be armed with them.

Lasers? In the documentary the way they were talking about the use of conventional fire arms (cannons, rifles ect) made it seem like ballistic weapons were extremely efficient and would never be used? at lease thats how I interpreted it.

Cannons and guns can be used in space and have, on the Almaz space station the Russians successfully fired a cannon.

Cannons, guns, nearly all types of weapons can not work in zero G but lets say you have a turret mounted on a ship with a lot of micro thrusters sensors all the important stuff.

Which ones did you have in mind? None current method of firing a weapon, that I can think of, has anything to do with gravity---all would fire. The big issue is handling the recoil from ballistic weapons.

Originally Posted by Lynx_Fox

Cannons, guns, nearly all types of weapons can not work in zero G but lets say you have a turret mounted on a ship with a lot of micro thrusters sensors all the important stuff.

Which ones did you have in mind? None current method of firing a weapon, that I can think of, has anything to do with gravity---all would fire. The big issue is handling the recoil from ballistic weapons.

"The big issue is handling the recoil from ballistic weapons" Sorry that's what I meant when I said "guns can't work in space" Ill rephrase that now on my OP.

I questioned this well watching a episode of Modern Marvels I think it was the episode Extreme aircraft II I could be wrong though. There was a simulation of the first space aircraft engaged in combat against another nation. They envisioned Ramjets flying in to orbit the Jets were were not able to stay in space, they had no micro thrusters and could not maneuver. They skipped in and out of atmosphere, they had no other weapons besides a single turret laser mounted underneath the aircraft, it said that conventional weapons would not be ideal in space, and that in the future spacecraft would be armed with them.

Lasers? In the documentary the way they were talking about the use of conventional fire arms (cannons, rifles ect) made it seem like ballistic weapons were extremely efficient and would never be used? at lease thats how I interpreted it.

Lasers while popular in scifi, leave a lot to be desired. They must be held on a target, they are relatively easy to defeat with high reflective surfaces or rotation. They work well against optics though...and blinding people.

Originally Posted by Lynx_Fox

Lasers while popular in scifi, leave a lot to be desired. They must be held on a target, they are relatively easy to defeat with high reflective surfaces or rotation. They work well against optics though...and blinding people.

And yet they kill storm troopers every single time without fail.

Unless you want to capture the flavor of a 1889 Retro sci-fi theme with pirate sail ships in space, why use cannons instead of missiles? Just shoot the missile from a long launch tube if you want a cannony look

(I cant delete this image)

sails
sails in space....

ride the solar winds
what good is a solar sail beyond the heliosphere?

cannons can be made recoiless-- so who you gonna shoot at?

Originally Posted by fizzlooney

cannons can be made recoiless-- so who you gonna shoot at?

Indeed we don't see um much anymore but we've used them before.

The real problem of trying to use cannons in space would be the relativistic speeds that the spacecraft are likely to be traveling at, how do you aim accurately at something that could be moving at tens or even hundreds of thousands of miles an hour. It might actually be far easier to just let objects of sufficient mass drift into the impact path of an enermy space craft and let it's own approach velosity increase the kinetic energy of the potential impact.

Also, I'm wondering if it would be difficult to maintain the right amount of gas pressure in the barrel when you're firing it. On earth, that barrel is full of air at 1 atm. In space, you have to fill it with air, which will scatter in all directions the moment it gets out into space. It's probably a solvable problem, but it seems like it would throw up some technical problems trying to actually implement it. At a minimum the radical change in pressure would have to add stress to the materials.

Using rail guns instead of explosive propellants would solve that somewhat, but then how do you cool the rails?

In space, you have to fill it with air,

Why. The propellent works due to Newton's third law....the surrounding air makes no difference.

Originally Posted by kojax

Also, I'm wondering if it would be difficult to maintain the right amount of gas pressure in the barrel when you're firing it. On earth, that barrel is full of air at 1 atm. In space, you have to fill it with air, which will scatter in all directions the moment it gets out into space. It's probably a solvable problem, but it seems like it would throw up some technical problems trying to actually implement it. At a minimum the radical change in pressure would have to add stress to the materials.

I'm also curious as to why you think it would be necessary to have air in the barrel.

Also, I'm wondering if it would be difficult to maintain the right amount of gas pressure in the barrel when you're firing it. On earth, that barrel is full of air at 1 atm. In space, you have to fill it with air, which will scatter in all directions the moment it gets out into space. It's probably a solvable problem, but it seems like it would throw up some technical problems trying to actually implement it. At a minimum the radical change in pressure would have to add stress to the materials.

Bullet is self-contained (it doesn't need air to explode) and so your pistol could even work in space! (OMG it so hi tech!)
But I also saw something in documentary (maybe Modern Marvel) about rocket propelled bullet. You just attach a solid rocket propellant on a bullet and it will became a tiny rocket & is recoiless.

I think space-ship doesn't want a cannon as weapon because fuel is expensive. Probably it took million of $ to take a Kg of fuel into orbit, and maybe a Kg is wasted to correct for weapons recoil. Maybe laser is lighter...

I guess I'm just thinking about how to keep the gases contained. Probably it's not an issue. I want to think that the pressure gradient would be more extreme, since the area on one side of the bullet is a vacuum with a pressure of almost absolute zero, but maybe that also would not be any more difficult?

Thinking of Carnot's law, one side of our heat engine is really, really cold at ~3 Kelvin.

I think the gas expansion will be just like rocket nozzle: a more efficient thrust at vaccum than at amospheric pressure.

Originally Posted by msafwan

Also, I'm wondering if it would be difficult to maintain the right amount of gas pressure in the barrel when you're firing it. On earth, that barrel is full of air at 1 atm. In space, you have to fill it with air, which will scatter in all directions the moment it gets out into space. It's probably a solvable problem, but it seems like it would throw up some technical problems trying to actually implement it. At a minimum the radical change in pressure would have to add stress to the materials.

Bullet is self-contained (it doesn't need air to explode) and so your pistol could even work in space! (OMG it so hi tech!)
But I also saw something in documentary (maybe Modern Marvel) about rocket propelled bullet. You just attach a solid rocket propellant on a bullet and it will became a tiny rocket & is recoiless.

I think space-ship doesn't want a cannon as weapon because fuel is expensive. Probably it took million of $ to take a Kg of fuel into orbit, and maybe a Kg is wasted to correct for weapons recoil. Maybe laser is lighter...

That would be the famous Gyro-jet weapon. The US military experimented with them back in the 60's but with little success as the rounds tend to veer off target. In addition point blank muzzle velocity was extremely low. You can read all about them here Gyrojet - Wikipedia, the free encyclopedia
Most likely space combat will involve the use of Magnetic Accelerator Cannons and Missiles. With a cannon you have to pack more. A traditional cannon has the round and the propellant charge while a missile is self contained. Eventually we may fight with Particle Cannons and such the US military is currently trying to develop effective projected energy weapons other than lasers due to the limited abilities of a laser weapon.

Originally Posted by wallaby

Originally Posted by Lynx_Fox

Lasers while popular in scifi, leave a lot to be desired. They must be held on a target, they are relatively easy to defeat with high reflective surfaces or rotation. They work well against optics though...and blinding people.

And yet they kill storm troopers every single time without fail.

Star Wars blasters are not lasers! Here is the proof:

An Analysis of Blaster Fire in Star Wars | Wired Science | Wired.com

Originally Posted by dmwyant

Eventually we may fight with Particle Cannons and such the US military is currently trying to develop effective projected energy weapons other than lasers due to the limited abilities of a laser weapon.

Yeah. That seems more likely. Launching projectiles inside the atmosphere we have to deal with atmospheric drag, which makes most super-high-velocity projectile weapons (including particle beams) somewhat impractical because most of the velocity will be lost in a very short time. The atmospheric drag increases as the square of velocity, so a super high velocity projectile is slowed by it more than a low velocity one.

Drag (physics) - Wikipedia, the free encyclopedia


In space, we'd be getting maximum destructive force if our projectiles had a mass that was next to nothing so they could travel at the highest speeds possible. (To max out kinetic energy, which also increases as the square of velocity )

"An object in motion tends to stay in motion unless acted upon by an external force." This makes Sir Isaac Newton the deadliest son-of-a-bitch in space.

Originally Posted by dmwyant

"An object in motion tends to stay in motion unless acted upon by an external force." This makes Sir Isaac Newton the deadliest son-of-a-bitch in space.

Hey I just recognized that saying, you got that from Mass effect 3 right?!
"Sir Isaac Newton the deadliest son-of-a-bitch in space."

Mass Effect 2 actually. The seargent bawling out the two gunnery recruits outside the customs depot. Nice catch I was wondering if anyone would get that one.

What kind of sensors would be used by warships in space? And would warship, presumably stealth be able to detect another ship that's somewhere out there in the solar system?

In space, an object's heat makes it visible because all warm objects radiate black body radiation. On Earth, the atmosphere absorbs, reflects, or distorts some of it so you can't always see everyone. Basically, this black body radiation is all-but-impossible to contain. The background heat in space is only about 2.725 Kelvin, a very very small amount. The outer surface of your ship has to be that cold in order not to radiate a detectable signature.

Blackbody radiation covers a wide range of frequencies, so you also can't just use a mirror to reflect it. The mirror would not cover the full spectrum.

I have always envisioned space combat to be similar to submarine combat. Windows are pointless on a combat vehicle in space. They are just a structural weakness. One would rely on sensors alone as the ranges involved in space combat would be vast. If ships engaging each other approached to within visual range one should have already destroyed the other. As for detection- Would the Redshift/Blueshift of signals from ships help in detection?

Excellent point Kojax.

Couldnt you cover the ship with cryo something plates that are super-cooled on top of a layer who's heat is converted into some other energy?

And if the hull gets to be the same signature as a small asteroid, wouldnt it be difficult to tell if the ship is not a hunk of rock in orbit around saturn or near the asteroid belt? In the case of a ship near the asteroid belt, detecting it isnt the problem, the problem might be to tell it appart from the rest, a bit like a plane flying with lots of chaff to the radar with a truck load of false positives?

Maybe warships could be designed to have the shape of an asteroid with small craters, the small craters being disguised thruster exhaust, missile hatch, and sensor dish, etc.

Originally Posted by icewendigo

Couldnt you cover the ship with cryo something plates that are super-cooled on top of a layer who's heat is converted into some other energy?

The only known way to convert heat into another form of energy is to let it flow toward a cold sink of some kind. This can also be done in reverse, using electricity to transfer heat from one surface to another, so one gets very cold and the other gets very hot. However, you can't make the heat disappear. It will end up somewhere.

Refrigerators operate on that principle, by being a heat pump. They make the outside of the refrigerator more warm, so the inside can be less warm. They don't diminish the total heat of their environment, though. (In fact, the overall net effect is that they increase the total amount of heat.)

I suppose if you know where the detector is, then you could super cool a small surface, and insert it somewhere in the line of sight between that detector and your ship. By choosing where you put it strategically, your ship could effectively be invisible from that observation point. Think of like how a solar eclipse works. The Moon is smaller than the Sun, but it still can block our view of the Sun if it's in the right place between our line of sight to the Sun.

And if the hull gets to be the same signature as a small asteroid, wouldnt it be difficult to tell if the ship is not a hunk of rock in orbit around saturn or near the asteroid belt? In the case of a ship near the asteroid belt, detecting it isnt the problem, the problem might be to tell it appart from the rest, a bit like a plane flying with lots of chaff to the radar with a truck load of false positives?

Yeah. If you moved like an Asteroid, you could probably camoflauge as one, or if you shadowed one. Probably the detectors would not be good enough to see whether there are two objects traveling together rather than one, as long as their brightness was about the same. A dot is a dot.

One thing about low level black body radiation is that most of the light is below the visible spectrum. There is a limit to the resolving power of any telescope to tell what exact direction a beam of light is coming from, and this limit gets worse the lower the frequency is. So for a satellite scanning for black body radiation from asteroids, its resolving power would likely be very limited. It can tell where the asteroid is, but all it sees is a blurr coming from that direction.

Originally Posted by icewendigo

Unless you want to capture the flavor of a 1889 Retro sci-fi theme with pirate sail ships in space, why use cannons instead of missiles? Just shoot the missile from a long launch tube if you want a cannony look

Off the top of my head, cannons might be useful for: 1. Defense against missiles 2. Shooting at things that are too close to use missiles 3. If you want to damage/cripple an enemy without totally destroying them 4. Shooting at things that aren't worth a missile (if you just want to destroy some dinky little satellite, you might not want to use a big, expensive missile that's meant for attacking enemy warships.) Also, cannons can attack many different target very quickly, for relatively little space. A ship could probably carry a lot more bullets than it could missiles.Others have mentioned things like lasers, particle beams, rail guns, etc. Those all have the big advantage of shots that travel much faster, so it would probably be easier to hit things that are far away. But they have the disadvantage of needing very large power sources, so they would probably take up a lot more room in your ship. They would probably also need more time between shots, which would make it harder to attack many targets at one, or to "saturate" an area with fire.

Originally Posted by kojax

Yeah. If you moved like an Asteroid, you could probably camoflauge as one, or if you shadowed one. Probably the detectors would not be good enough to see whether there are two objects traveling together rather than one, as long as their brightness was about the same. A dot is a dot.

I agree, but the problem is that most asteroids aren't moving very fast, and aren't likely to be going in the direction you want your warship to go. You probably don't want to wait around for decades as you sloooooowly drift toward your target. If there is an asteroid that is both moving very fast and going to pass close to something of military importance, it's probably a good bet that your enemy will take a VERY close look at it before it gets too close. Although I guess it might work if you were willing to send out automated weapons years in advance, and wait for them to slowly sneak close to their targets.

One thing about low level black body radiation is that most of the light is below the visible spectrum. There is a limit to the resolving power of any telescope to tell what exact direction a beam of light is coming from, and this limit gets worse the lower the frequency is. So for a satellite scanning for black body radiation from asteroids, its resolving power would likely be very limited. It can tell where the asteroid is, but all it sees is a blurr coming from that direction.

I think this problem can be solved by using several space-based telescopes combined into one interferometric telescope...

What a lot of you a failing to take into consideration is high recoil weapons are designed for the ground. And would never be used in space, Most modern high power weapon systems use intricate hydraulics amongst other things to absorb, Making them practically recoil free. These weapon systems would have little to no effect on the trajectory or position on a space craft, While lasers are not as powerfull as in movies like starwars yet, I feel that they soon will be. But for now I would say aerospace warfare will consist majorlyof rockets/missles.

Originally Posted by Dr.Aragonto

What a lot of you a failing to take into consideration is high recoil weapons are designed for the ground. And would never be used in space, Most modern high power weapon systems use intricate hydraulics amongst other things to absorb, Making them practically recoil free. These weapon systems would have little to no effect on the trajectory or position on a space craft, While lasers are not as powerfull as in movies like starwars yet, I feel that they soon will be. But for now I would say aerospace warfare will consist majorlyof rockets/missles.

What your failing to take in to consideration is that space is vast and so what if we wonder off a few hundred kilometers, and its no problem keeping the vehicle stable or in the battlefield when these craft will have lots of point maneuvering thrusters combined with hard worked and well thought of computer software and systems. Space is not the same as the ground warfare we see today, nothing would be static up their.

I did not fail to take any of that into consideration. How can you say its no issue for a space craft to wander a few 100km? Yes space is thousands of light years in all directions. But I can guarantee they will never deploy a weapon that causes the space craft to wander. Just like land/sea/and air warfare, some locations have strategic uses, and they wouldn't want there ship being dragged away after firing on a enemy target. What I agree with you about is that they will probably deploy intricate thruster systems to counter the weapons recoil. Your statement saying no weapon would be recoiless in space is ill worded. As I will give you an example the AR-12 automatic 12gauge shot gun has so little recoil that it can be fired from one hand in the most weird positions that with other weapons would make impossibe. I'm not saying they would use it for space warfare. Just using it as an example.