Firearm heat management in space
- Thread starter Roboss
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Improved heat conduction materials (barrel/chamber coolers, insulating materials, ...)
Improved heat radiation design (fins, coolant, peltier)
Reduce excess heat in propellant.
Try a search for shooting in space on THR and you'll find some old discussions that might touch on this.
Understand that asking questions without a clear answer, e.g. "In the future", need to be carefully considered for what can be answered.
Improved heat radiation design (fins, coolant, peltier)
Reduce excess heat in propellant.
Try a search for shooting in space on THR and you'll find some old discussions that might touch on this.
Understand that asking questions without a clear answer, e.g. "In the future", need to be carefully considered for what can be answered.
robert4301
Member
Just shade it from sunlight. It's 200-odd degrees below zero in the shade. The heat would radiate away very quickly.
mcb
Member
There is pretty good evidence the Russian design and fired a medium bore (23mm) weapons system on a space craft, it was to be used to defend their space station.
Assuming we are talking about shooting guns in a vacuum, heat is probably the biggest issue since although space is very cold, a vacuum is a very good insulator (think your vacuum thermos). A gun in a standard atmosphere can get rid of waste heat through conduction, convection and radiation. You loose convection completely since you have no atmosphere around it in a vacuum and conduction become difficult in many mounting situations. Radiant heat loss becomes you primary means and it is not near fast enough without design changes to existing weapon systems.
Long exposure to vacuum also causes lubricants to evaporate at rates much higher than standard atmospheric conditions. It's not super fast, ie minutes or hours, for most lubricants but still in days or weeks most standard lubricants are going to evaporate.
In extreme cases once the lubrication is gone you can possible have problems with parts actually sticking together due to cold vacuum welding of the parts. This has been document as a problem in early satellite mechanism.
Heat management in space is a difficult problem for most systems. Look how big the heat radiators and coolant systems are for the space station.
Assuming we are talking about shooting guns in a vacuum, heat is probably the biggest issue since although space is very cold, a vacuum is a very good insulator (think your vacuum thermos). A gun in a standard atmosphere can get rid of waste heat through conduction, convection and radiation. You loose convection completely since you have no atmosphere around it in a vacuum and conduction become difficult in many mounting situations. Radiant heat loss becomes you primary means and it is not near fast enough without design changes to existing weapon systems.
Long exposure to vacuum also causes lubricants to evaporate at rates much higher than standard atmospheric conditions. It's not super fast, ie minutes or hours, for most lubricants but still in days or weeks most standard lubricants are going to evaporate.
In extreme cases once the lubrication is gone you can possible have problems with parts actually sticking together due to cold vacuum welding of the parts. This has been document as a problem in early satellite mechanism.
Heat management in space is a difficult problem for most systems. Look how big the heat radiators and coolant systems are for the space station.
Ed Ames
Member
Everything is engineered for an environment.
If you were engineering a rifle for microgravity vacuum use (not inside a vehicle or on the ground after landing), I expect you would start with recoil management as a requirement. Recoil management could help with thermal management. E.g. the mass accelerated backwards to provide counter-force to recoil could carry heat away.
You also need to count the possibility that a “gun” for that environment could be nothing like a gun as we would imagine on earth. For example the “gun” could end up being a magazine and launch system that deploys the projectiles laterally so the rocket exhaust wouldn’t impact the user. The gun could use a laser emitter to paint the target and tracking systems in the projectiles to let them guide themselves to whatever the laser is marking. Firing would look like a cartridge - or balanced pair of cartridges - launching a few meters sideways before accelerating and steering towards the target.
If you were engineering a rifle for microgravity vacuum use (not inside a vehicle or on the ground after landing), I expect you would start with recoil management as a requirement. Recoil management could help with thermal management. E.g. the mass accelerated backwards to provide counter-force to recoil could carry heat away.
You also need to count the possibility that a “gun” for that environment could be nothing like a gun as we would imagine on earth. For example the “gun” could end up being a magazine and launch system that deploys the projectiles laterally so the rocket exhaust wouldn’t impact the user. The gun could use a laser emitter to paint the target and tracking systems in the projectiles to let them guide themselves to whatever the laser is marking. Firing would look like a cartridge - or balanced pair of cartridges - launching a few meters sideways before accelerating and steering towards the target.
DocRock
member
Recoil management may be a bigger concern.
silicosys4
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Purely radiant heat loss is a slow process. There is nothing in the vacuum of space to conduct heat away so I think the heat loss process would be pretty slow through purely radiant means. I've read some discussions on what space would actually "feel" like and consensus was that space would feel "prickly" as the surface moisture boils away from your skin, then slightly cold as there is nothing to actually conduct heat away from the skin so that "200 below zero" becomes much less of a factor.
AFAIK, liquids don't freeze under vacuum, they boil. I'm guessing that oil wouldn't freeze but it might boil away relatively quickly, so something like grease might be necessary. I don't think the cold would affect the lubricant as much as you might think because there is nothing conducting the heat away from the lubricant so any heat loss would be radiated, a relatively slow process unless the gun has been exposed to space for a length of time. Then it might be cold enough that it might affect its mettalurgy, making it too brittle to fire safely. This is all purely speculation though. I haven't heard that spacecraft have a problem with cold affecting the metallurgy of their metal parts so I honestly have no idea
There will be no gun battles in space though. Potential engagement distance is too great. There are no gravity factors hindering ballistics and limiting engagement distance, no trees to hide behind, no bunkers to hide in, no oceans to hinder advance. Just a target that is dead whenever you can land sufficient energy on it by whatever technology gives you the best reach and energy delivery. By the time you get into small arms range you would have been tracked by radar and destroyed with missiles or kinetic weapons long before. Battles will focus on stealth technology, tracking and maneuvering to avoid incoming shots, tracking and predicting the maneuvering of the adversary, and guidance systems...unless energy weapons are developed, and then all you can do is attach a bunch of mirrors to your spacecraft and hope you don't ricochet a laser blast into some poor sucker down on earth
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MedWheeler
Member
The Soviets carried a Makarov pistol on each mission for quite some time.
CapnMac
Member
Well, there is the issue that vacuum is a thermal insulator.
The big copper sheets on ISS are radiators, to dump the waste heat overboard, otherwise the place would cook.
Remember that vacuum is oted for not having that many molecules in it. So, a something at a high energy state really has noting to transfer that higher energy "to."
In a fluid like air, the nitrogen majority is willing to move to a higher energy state in response to a heated object--that's why cooling fins "work." You are moving heat from metal to the fluid surrounding it. Remove the fluid, and the heat transfer is also removed.
Physics is a cruel mistress.
The big copper sheets on ISS are radiators, to dump the waste heat overboard, otherwise the place would cook.
Remember that vacuum is oted for not having that many molecules in it. So, a something at a high energy state really has noting to transfer that higher energy "to."
In a fluid like air, the nitrogen majority is willing to move to a higher energy state in response to a heated object--that's why cooling fins "work." You are moving heat from metal to the fluid surrounding it. Remove the fluid, and the heat transfer is also removed.
Physics is a cruel mistress.
Alec
Member
Dangerous to whom?
Other and future spacecraft in Orbit.... There is already too much junk in space you know....
https://en.wikipedia.org/wiki/Space_debris
edwardware
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Why? You can attack and retreat at the same time! It's like a Monty Python sketch, but with Attack, and Run Away! simultaneously.
In all seriousness, heat dissipation into a vacuum is a seriously hard part of spacecraft design. Reflective foil to reduce solar heating, and dissipative fins on the dark side to shed heat as infrared are necessary features.
The simplest solution is to design your gun so it doesn't mind being hot for a long time after each use.
WestKentucky
Member
WestKentucky
Member
Water jackets might help just a bit, but the liquid cooled guns similar to those that were used in ww1 wouldn’t do much. High rate of fire would heat the barrel and the resultant heat exchange to the water in the water jacket would cause the water to boil. Boiling of water is a change in physical energy state and consumes a massive amount of energy. In space with a near total vacuum, achieving that energy state change would be hard to accomplish as the liquids (normally liquid rather) would be pushed to one extreme or the other depending upon conditions, and they would either freeze up or boil off before having a chance to consume any of the thermal energy.
WestKentucky
Member
Also, at extreme low temperature, metals get brittle. That might be a concern at extreme cold.
Dunross
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The Ultimate List of Weapons Astronauts Have Carried Into Orbit
https://gizmodo.com/the-ultimate-list-of-weapons-astronauts-have-carried-in-1768199454
No guns for American astronauts. Very bad mass to usefulness in space ratio.
https://gizmodo.com/the-ultimate-list-of-weapons-astronauts-have-carried-in-1768199454
No guns for American astronauts. Very bad mass to usefulness in space ratio.
Dunross
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This is true, but unlike the First World War water-cooled machine guns there would not be long bursts of full automatic fire. Far too expensive in terms of mass to haul into space, plus the recoil issues. Whatever gun fire there might be it would be semi-auto to short bursts. More time for the heat to transfer. To my mind the water jacket would be sealed and would only valve open to vent steam or hot water when the pressure inside the jacket rose to a pre-determined level.
Not that I think we're ever going to see much gun play in a near zero-g vacuum environment. If weapons were to become necessary there are other solutions for that.
Deus Machina
Member
Water cooling wouldn't be nearly as effective in space.
It would need to be in a pressurized system to avoid instantly boiling. Pressure raises boiling temperature--thus why the coolant in your car stays liquid at some of the temperatures it reaches, and conversely loss of pressure lowers the boiling point. In a near-absolute vacuum, to the point that there is a very small window where water would actually be liquid.
That's why divers have to surface slowly or rest in a decompression chamber. Gasses are forced to dissolve into the blood and the loss of pressure as they surface essentially boils them back out.
Of course, managing liquid cooling would still be much more effective than relying on radiant cooling.
Remember that space isn't necessarily cold, since there's nothing there to draw heat away. Cold things don't absorb heat from any source but light, and hot things don't have anything to transfer their heat to.
Another reason we're not likely to see gunfights in space. IMO, we're likely to see usable caseless firearms by then, but they would be even worse in space; the case serves a vital purpose of acting as a heat sink from the reaction, and a shield from the actual firearm, and discards the heat along with the casing. And getting enough cased ammunition up there to keep guns running would cost an absolute fortune.
It would need to be in a pressurized system to avoid instantly boiling. Pressure raises boiling temperature--thus why the coolant in your car stays liquid at some of the temperatures it reaches, and conversely loss of pressure lowers the boiling point. In a near-absolute vacuum, to the point that there is a very small window where water would actually be liquid.
That's why divers have to surface slowly or rest in a decompression chamber. Gasses are forced to dissolve into the blood and the loss of pressure as they surface essentially boils them back out.
Of course, managing liquid cooling would still be much more effective than relying on radiant cooling.
Remember that space isn't necessarily cold, since there's nothing there to draw heat away. Cold things don't absorb heat from any source but light, and hot things don't have anything to transfer their heat to.
Another reason we're not likely to see gunfights in space. IMO, we're likely to see usable caseless firearms by then, but they would be even worse in space; the case serves a vital purpose of acting as a heat sink from the reaction, and a shield from the actual firearm, and discards the heat along with the casing. And getting enough cased ammunition up there to keep guns running would cost an absolute fortune.
Tommygunn
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