Outer space presents an extreme environment that is vastly different from Earth. With no atmosphere and extremely low temperatures, one might wonder whether firearms are even capable of functioning properly in space.
The basics of how a gun fires
To understand how guns work in space, it is helpful to first review the mechanics of how they fire on Earth. There are three key components that allow a typical firearm to discharge:
- The primer – This is the impact-sensitive chemical compound located inside the base of the cartridge. When struck by the firing pin, the primer ignites.
- The propellant – Also known as gunpowder, this is the rapid-burning chemical mixture that creates an expanding gas once ignited by the primer.
- The projectile – This is the bullet or shot which sits in front of the propellant and is propelled forward once the propellant expands.
When the trigger is pulled, it releases the firing pin which strikes and ignites the primer. The burning primer then ignites the propellant, generating a rapid expansion of hot gas inside the cartridge. This buildup of gas pressure propels the projectile down the barrel and out the muzzle at high speed.
Do guns work the same in the vacuum of space?
Surprisingly, firearms are still capable of firing in the vacuum of space, though not in exactly the same way as on Earth. Here are some key differences:
- No atmospheric resistance – With no air resistance, the bullet will travel much farther and faster than on Earth.
- Barrel cooling – In space, only radiation can help cool the barrel rather than convection through air. This means barrels may overheat faster with repeated shots.
- Unburned residues – In space, the lack of atmospheric pressure means some residues may not fully burn and can foul the barrel faster.
- Recoil – With no air resistance, the recoil experienced by the shooter will be more direct and sharper.
Firing mechanisms are self-contained
The key factor that allows guns to work in space is that their firing mechanisms are entirely self-contained within the loaded cartridge. The primer contains both the impact-sensitive explosive mix and the oxidizer needed for ignition. The propellant also has its own oxidizer mixed in. This allows firing to occur even without external oxygen. As long as the firing sequence can be triggered, the gun can fire.
NASA tests confirm guns can fire
The functionality of firearms in space has been confirmed through tests done by NASA during the 1960s. As part of experiments to develop a space-based handheld maneuvering unit, NASA conducted tests to see whether guns could work in a vacuum environment.
A series of firearms including a .38 caliber police revolver, a 12-gauge shotgun, and other handguns were fired vertically in a vacuum chamber recreating space-like conditions. The guns were successfully fired and cycled normally, proving that a lack of atmosphere did not affect the immediate firing process.
However, the testing did reveal some differences compared to firing on Earth. Recoil was more pronounced and jarring without air resistance. Gases ejected from the barrel spread wider and did not dissipate as quickly in the vacuum. This resulted in some barrel overheating issues after repeated shots.
Bullets fly true but can travel long distances
One interesting effect of firing in space is that the bullets will fly extremely true once they leave the barrel of the gun. With no wind resistance or gravitational effects acting on the bullet, it will maintain its original trajectory almost perfectly.
The downside to this is the risk of bullets traveling enormous distances if they miss their target. With no atmospheric friction, air resistance or gravity to slow it down, a bullet could conceivably continue moving at lethal speeds indefinitely and cover an almost unlimited range.
For example, when firing parallel to the surface on Earth, a bullet may travel 1-2 miles before gravity finally pulls it to the ground. But that same bullet fired on level trajectory in space could theoretically travel for over 10,000 miles before hitting anything.
This raises serious safety concerns about the use of firearms in space habitats or around spacecraft. A missed shot has potential for catastrophic collateral damage.
Guns provide recoil thrust
An interesting space applications of firearms is that they can be used to provide a small amount of thrust. By firing a gun, the recoil effect produces an equal and opposite reaction force that can push objects in microgravity environments.
NASA again tested this concept during their experiments in the 1960s. They mounted a .38 caliber pistol on a floating platform to see if firing it could move the platform. After several shots, they did observe a small translational displacement of the platform in the opposite direction.
While the thrust produced is very minimal, this recoil effect could conceivably be used for small trajectory corrections and attitude control adjustments on deep space missions. The “gun thruster” concept has been proposed by physicists but has not yet been demonstrated on any actual spaceflights.
Noise and muzzle flash still occur
Two iconic effects of firing guns – the loud bang and bright muzzle flash – still occur when guns are fired in space. This is because neither effect requires an atmosphere.
The noise is caused by rapidly expanding gasses within the cartridge produce a shockwave. Sound, or mechanical vibration, can travel through materials so the bang sound is transmitted through the solid structure of the gun and to any nearby objects like the shooter’s spacesuit.
Muzzle flash comes from left over gunpowder combusting at high temperatures after the bullet exits the barrel. An atmosphere is not needed for this brief burst of light.
However, the noise and flash dissipate faster without any air to carry them. The shockwave dies out more quickly and the muzzle flash appears brighter but vanishes rapidly. So firing a gun in space can seem muted compared to within Earth’s atmosphere.
Issues requiring atmosphere
While the chemical reaction of firing can occur normally in a vacuum, there are some secondary effects of firing a gun that do require atmosphere:
- Gas ejection – Gasses and casings are ejected out unfolding actions like auto-reloading. These need air resistance to fully clear the gun mechanism.
- Barrel cooling – Air convection helps dissipate heat buildup in barrels from repeated shots. Without atmosphere, barrels overheat faster.
- Unburned residues – Some propellant residues need atmospheric oxygen to fully combust. In space, fouling issues can occur faster.
- Cordite propellants – Cordites are nitrocellulose-based propellants relying on surrounding air pressure for optimal burn. They are less reliable in vacuum environments.
These factors limit effective rates of fire and life of firearms in space conditions compared to on Earth. But with the right propellants and design considerations, these issues can be mitigated.
Challenges of firing guns in space suits
For a person to fire a gun in space, they need to be wearing a pressurized space suit. This presents some unique challenges:
- Restricted mobility – The stiff pressurized gloves of a spacesuit reduce range of motion and dexterity to handle guns properly.
- Trigger pull – Extra force is needed to pull the trigger against the internal glove pressure.
- Loading cartridges – Manually reloading guns requires fine motor skills difficult in thick gloves.
- Vision – Helmet visors can fog up, causing viewing issues. Spacesuit helmets also limit peripheral vision.
- Recoil issues – Recoil force is directly transmitted to the shooter’s body through the suit with no cushioning effect from air resistance.
With practice, astronauts can adapt their techniques to handle and fire guns reasonably well in space suits. But it does require overcoming some challenges the bulky protective gear presents. The gun designs also need to have some specialized adaptations for easier use by a suited space shooter.
Hazards guns present aboard spacecraft
The confined environment inside a spacecraft generates some unique risks if a firearm is discharged aboard:
- Over-penetration – Bullets can go through thin spacecraft walls and damage critical systems.
- Depressurization – If a bullet punctures the hull, it risks rapid loss of internal atmosphere.
- Ricochets – Hard surfaces inside a spacecraft increase likelihood of bullet fragmentation and unpredictable ricochets after impact.
- Toxic residues – Combustion residues from firing guns can contaminate the internal atmosphere of a spacecraft.
These risks mean that extreme caution must be taken if guns are ever to be safely fired aboard a spacecraft. Protective shielding, expanding “frangible” ammunition, and other countermeasures would be necessary.
Space gun alternatives under development
Due to the various disadvantages of conventional firearms in space, several alternative weapon technologies have been proposed specifically for space use:
Metal particulate “space shotguns”
Instead of traditional pellets, these shotgun-like weapons fire a spray of tiny inert metal particulates at high speed. The particulates spread quickly in zero gravity conditions upon firing forming an expanding cone of projectiles. Benefits include reduced risk of hull penetration while disabling targets at short range.
Energy beam weapons
Focused laser, plasma, and particle beam weapons can be designed with little recoil effect. They also offer pinpoint accuracy and can have adjustable effects from non-lethal to lethal. Downsides include bulky power supply requirements.
Gyrojet rockets
Miniature self-propelled rockets which are much slower accelerating than bullets, but reach higher final velocity. Their low recoil eliminates issues with firing in spacesuits and they can be made steerable post-firing. However, the high velocity upon impact poses risk of hull penetration.
More testing needs to be done to assess whether any of these futuristic armaments are practical for space combat. But they highlight attempted solutions to the challenges posed by traditional firearms in space environments.
Conclusion
Guns can definitely still be fired and operate in the airless environment of outer space. However, the lack of atmosphere creates unique considerations compared to firing on Earth. Recoil is more pronounced, barrels overheat faster, residues may not fully combust, and there are risks from rounds impacting spacecraft walls. With proper designs and handling procedures, firearms remain functional for space use. But given the hazards involved, they are still not an ideal solution and experimental space weaponry continues to be developed.