While reading Seveneves by Neal Stephenson, I realized that most combat techniques don't work as well in space. Old fashioned hand to hand combat and swordplay don't work since there's no footing and even if you hit someone you'll also be launched in the opposite direction. Firearms are absolutely out of the picture because of recoil. Laser guns haven't been invented. Wrestling will work but I imagine mobility will be an issue.

So what will a realistic forms of physical combat be in space?

Edit: By "combat" I mean the kind of force applied by police, not military. The tech level should be effectively modern-day.

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    $\begingroup$ Your question invites brainstorming... asking for a list of all the things compatible with X is not really the right sort of question for stackexchange sites, because the list is open ended. What sort of combat are you thinking of? Sport? Entertainment? Police actions? Other than "no lasers", what sort of tech-level are you thinking of? You should do something to narrow stuff down, like suggesting a scenario you'd like people to address. $\endgroup$ Mar 23, 2022 at 11:40
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    $\begingroup$ Good start! Now, the tech level can't quite be the same as us, as we don't have a whole lot of people in space. What's the setting? Spaceship flying somewhere? non-spun space station in orbit around somewhere? Mining facility? Is it all confined spaces (like the ISS, or the interior of a submarine) or are there big open volumes people can fly around in? $\endgroup$ Mar 23, 2022 at 12:08
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    $\begingroup$ When I was suggesting you describe a scenario, I was thinking of something like "how would the police in spaaaace subdue an unarmed resisting subject in an environment that looks like the interior of a large ikea store" , or whatever. More specific questions are likely to get you better answers. $\endgroup$ Mar 23, 2022 at 13:06
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    $\begingroup$ How is the first comment on this question not "The enemy's gate is down." !? $\endgroup$
    – Qami
    Mar 23, 2022 at 19:38
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    $\begingroup$ Turrets come out of the ceiling and kill anyone who isn't encoded with the correct FoF identification. $\endgroup$
    – Mazura
    Mar 24, 2022 at 0:47

7 Answers 7


It depends a bit on your environment

Grappling training will remain the main tool of police forces

Like here on Earth, over 90% of resisting suspects will still be detained through grappling alone. While grappling styles change in zero-G, once you have a hold on your opponent, neither of you are just flying off. So, it's only really when the law needs to resort to lethal force that things get all that different.

For melee in a confined, O2 rich environment: Use a knife or short sword

One of the biggest reasons to prefer a shorter blade over a longer one is that they are easy to use in a grapple. If you can grapple an opponent with one hand, then you can deliver a powerful thrust with the other without pushing them back. They are also easy to get into any vulnerable gaps in the body armor, thick clothing, or space suits your enemies may have.

enter image description here

For a melee in a vacuum and/or more open environment: Use a guisarme

If you are fighting in space suits, a kill shot is not a big deep wound, but any small cut the puts a hole in your opponent's space suit. Guisarmes would give a big reach advantage, allow you to hook onto things and drag yourself back to handholds if you become dislodged, and it's thin hook and point combo is perfect for making the kind of small holes that would kill an enemy in the vacuum of space.

Despite what you may think, such a weapon can deliver a kill blow even without a hand-hold. One of the big mistakes novice astronauts make is assuming that weightlessness is the same as not having inertia. If you swing or thrust a polearm, yes you can not drive the weapon through like you can when you can brace your feet, but it can still hit hard enough to punch a hole in the fabric of a space suit. Infact, if you stab another person with a polearm, you can then use them as a counterweight to re-establish your orientation before extracting your weapon.

enter image description here

For Ranged Combat: use a recoilless rifle

While traditional bullets inherently impart recoil on the gun to recapture some of the reaction force and direct it back into the slug, a recoilless rifle is one that has no back-face to press into. Instead, the back of your firearm is an open hole that simply lets the reactive forces vent out the back. This makes for a less efficient firearm, but with a slightly bigger bullet, you can still achieve the same stopping power. We use this technology here on Earth to make shoulder fired anti-tank rifles, but scaled down, this same idea could be used to make a virtually recoilless anti-personnel rifle. You just need to make sure to extend a vent barrel backwards enough that you don't accidentally point it at yourself as you fire. I would also suggest pairing this with caseless ammunition such that the blow back is only a gaseous fire ball and not a brass case being shot back with nearly as much lethality as the bullet flying forward.

Also, depending on the nature of where these police forces are, normal bullets may pose a major risk to the habitat via hull breech. If we are talking about a base buried deep in the middle of an asteroid, or a mega structure that needs several meter thick walls for integrity purposes, then normal bullets would not pose a significant risk, but if we are talking a much smaller space habitat with thinner walls like the international space station, then you may need to avoid normal bullets, but the same principles could still apply to something like a harpoon gun. Using a slower, heavier projectile will still pernitrate flesh or the cloth bits of a space suit, but be much less likely to pernitrate your environment's walls.

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    $\begingroup$ Should probably avoid firing traditional bullets on a spaceship. A miss (or even a hit which passes through the victim) could punch a hole in the walls resulting in explosive decompression that kills everyone on both sides. $\endgroup$ Mar 24, 2022 at 13:37
  • $\begingroup$ @DarrelHoffman Good point. I've added a bit to cover situations where this might come up. $\endgroup$
    – Nosajimiki
    Mar 24, 2022 at 14:00
  • $\begingroup$ Modern so-called "recoilless" rifles definitely do NOT have zero recoil. Even a note from the article referenced states: "Despite the name, it is rare for the forces to completely balance, and real-world recoilless rifles do recoil noticeably (with varying degrees of severity)." $\endgroup$
    – CitizenRon
    Mar 28, 2022 at 16:52
  • $\begingroup$ @CitizenRon Ofcouse they do, but that is an 84mm anti-tank cannon that reduces recoil enough to be fired from a standing position. Even if you reduced 99.9% of the recoil of a riffle that sized, it would have some serious kick. I am not suggesting using 84mm weapons, but if you used the same method to reduce the recoil of a 5.56mm, then even in zero G the recoil will be negligible as each bullet would impose no more than 1 or 2 Newtons of recoil. So even unloading a whole clip would accelerate you backwards less than 1m/s. $\endgroup$
    – Nosajimiki
    Mar 28, 2022 at 17:56
  • $\begingroup$ I feel like this should reference the gyrojet en.wikipedia.org/wiki/Gyrojet $\endgroup$
    – DWKraus
    Apr 5, 2022 at 14:41

Thrown animals.

thrown cat


The problem with grappling with people is those people probably have cooties. Then you have them too and your mom will make you hose off in the driveway before you can come inside. Then someone posts the video, again.

Better to have animals do your fighting for you. The police will have small but very fierce animals they will throw at people they wish to fight. In zero-G it will be easy to throw animals because they will not have to deal with parabolas.

The police will have an assortment of animals. Hoofed animals are unsuitable because they can't hang on to the people they hit; red foxes also would struggle but gray foxes are OK because they are good climbers. Other suitable animals would be cat, weasels, skunks, squirrels (to deal with protestors), rats, iguanas, cat(s) where 2 small instead of 1 large would be used, and monkeys with needles and syringes full of hallucinogen.

The animals would themselves probably have cooties but the police would have gloves and also smocks that say POLICE, in vertical letters.

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    $\begingroup$ I forgot raccoons. Those for sure. $\endgroup$
    – Willk
    Mar 23, 2022 at 14:39
  • $\begingroup$ FB... SPCA open up! $\endgroup$
    – user6760
    Mar 23, 2022 at 14:42
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    $\begingroup$ Do you want zoonotic cooties? Because this is how you get zoonotic cooties. $\endgroup$ Mar 23, 2022 at 16:14
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    $\begingroup$ Downvoted for unrealism. Goats have hooves and are great climbers. Goats are also large so they hit the baddies pretty hard on impact. And they have natural handles, two of them, attached to their heads, to facilitate throwing. Throwing goats down the space corridors will be the accepted meta. Educate yourself son. $\endgroup$
    – Daron
    Mar 23, 2022 at 18:16
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    $\begingroup$ @AustinHemmelgarn Perhaps if someone has bought a new moon car with the fancy no-scratch coating, a goat would be the ideal tool of sabotage. But there is no need to actually throw the goat, the goat found the shiny freshly-waxed moon car 10 minutes ago, and it already has $8000 worth of damage. Furthermore, your moon car insurance does not cover goat collision. In any other scenario, goats are more hassle than they're worth. You're all shills for Big Goat. $\endgroup$
    – John O
    Mar 24, 2022 at 5:17

The novel Ender’s Game by Orson Scott Card explains every aspect of zero gravity combat, covering the complete training from a new recruit to a seasoned fighter. It details the weapons used as well as tactics, and configuring a training arena.

A second source is Perdition’s Pocket by E. W. Finch III in the Star Seeker series. This setting interlaces zero gravity with multi-directional gravity, describing how you would move from one direction to another.

Human senses: You do need to consider human physiology in this, which Finch goes into in great detail. Your body is designed to expect gravity pulling toward your feet. Most untrained people will feel sick if they move between areas with different gravity. Here is a quote from Star Seeker:

“Oh, I forgotz ta tell you,” their guide smirked. “The gravity ‘n the upper cargo deck iz rotated 90 degreez.” Even forewarned, most of the midshipmen felt queasy as they crossed the threshold. Their bodies didn’t respond well to having its eyes and ears, the tools for balance, in a different gravity orientation than the rest of its systems. The disagreement between clashing sensations met somewhere around the stomach region.

Combatants will need regular training just like astronauts.

Ship design considerations: If combat is expected, your ships and stations need to account for this, with visual guides. Another example using ladders for reference:

When they entered the crew deck from the cargo hold, at least they were forewarned. The presence of a ladder told them which way the gravity went. It was a lot easier to crawl on the floor and grab the ladder through the meshing zone than the reverse had been.

Operational considerations: The way a ship operates can provide a serious advantage against any intruder. Finch often left regions of the ship evacuated to disorient intruders:

Much of the combat was done in zero gravity. Some of it was also done in vacc suits. It was Scout standard operating procedure that in a combat situation that ship’s air be vented. It made boarding more difficult for an enemy unfamiliar with the ship and lessened the damage to ship’s crew and systems if the ship took a serious hit and lost atmosphere.

Weapon design: Finch uses a “needler” gun which is just a gause rifle. The apparent advantages are:

In shooting, Jason took the lead. He had been in competition shooting before the Corps. It took some adjustment to get used to a “needler,” officially known as a “gauss carbine” in the Corps. Instead of gun powder throwing lead slugs, the needler used an electromagnetic pulse to send a steel needle to its target. With little recoil, no muzzle flash and enough bite to penetrate a space suit, the needler was the ideal weapon for space.

None of these use any radical theoretical weapons. Ender trained essentially with laser tag rifles which we use today. The suits made it realistic by disabling your arm or leg if you got hit there.

This is your best source for a complete solution in your world.

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    $\begingroup$ well... the recoil would come from the entire rifle moving backwards, cuz, y'know, newton's third law $\endgroup$
    – somebody
    Mar 23, 2022 at 20:37
  • $\begingroup$ @Yeah I didn’t find the details of the bullet but it has to be a lower mass than a lead slug, and/or lower velocity. But it doesn’t need to overcome a falling bullet either. It’s possible to have a benefit here. I’m sure a .44 magnum in zero would be unmanageable! $\endgroup$
    – Vogon Poet
    Mar 23, 2022 at 20:43
  • $\begingroup$ see OP though - the recoil might not be much at first... but when you're constantly firing slugs, no matter how small... with no friction to stop you from accelerating backwards i'd imagine space combat to be a massive headache, if not completely unreasonable to stay in close quarters $\endgroup$
    – somebody
    Mar 23, 2022 at 20:54
  • $\begingroup$ Slug throwers in general are A Bad Idea. The kinetic energy in the slug - even flechettes - is exactly the same as the kinetic energy imparted as recoil. The exceptions are weapons that produce a balanced counter-thrust in some way, or gyrojets where the projectile is a little rocket. Flechettes produce significantly less recoil than .45 pistols though, so they might be manageable enough. $\endgroup$
    – Corey
    Mar 24, 2022 at 1:11
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    $\begingroup$ I don't see why the recoil would be a problem. I was pushed back, you got shot, tell me who won the fight (while you still can). It doesn't matter how far I was pushed back (to a limit, obviously), I can always fire the same number of shots in the opposite direction (provided I have the ammo). So, I'll grab double magazines and let's dance! $\endgroup$ Mar 24, 2022 at 21:19

Punching and sword work fine, if you have a secure footing. There are some great, though graphic, scenes of this in the book ‘Ender’s Game’ — but the short version is that you grab a rail or handhold, and continue to pummel the other person until they are mush, switching handholds when necessary.

In close corridors, that’s probably how it will work. The “terrain advantage” is having muscle memory about the best handholds, but could be overcome by people with equipment to “dig in” wherever they are at.

In wide open spaces, things get more interesting. Hopefully a well-constructed open space has been built with kids and fools in mind: there are cleverly concealed, but nevertheless “there when you need them” handholds placed always close by in this open space, so that there are floating aeroponics, floating lights, or maybe floating billboards that are all anchored to the ground by slender and strong poles — serving a dual purpose as decoration, and safety net.

Again, like ground combat, it’s all about position and footholds, but now the mess is in all three dimensions. A sound tactician is trying to figure out visually which of the many ways of crossing the terrain are quickest, offer the most places to dig in and fight, and least fatiguing. A modestly fit human who could catch about a meter of air on the ground can launch themselves at 4.4 m/s, and is spending a lot fewer calories in one bound than a troop “hamstering” through a nest of little access tunnels to make it to the same point.

Speaking of fitness, it should be important to point out that Earth is the only 1 gee habitable world in the solar system. Most other rock bodies are 1/6th gee, or tiny asteroids with nearly nothing. For trained forces trying to stay fit, it’s not a big deal - but a recently launched from Earth force against mustered civilians in six times stronger than the locals, up to a hundred times stronger than those clinging to a no gravity rock and not bothering to stay active — they will move more slowly and be more fragile. However, mass doesn’t change — so a spacer “can” remain as fit as an Earther, but they must work at it.

Outside, things are a bit different. A good metaphor for fighting in this condition would be two armies pitched at a cliff side : a false step will send you off the cliff (into deep space). Having “the cliff at your back” is an unenviable position where the enemy controls all of the ingress/egress points, and you are fighting from a location that is totally exposed, with only the void around you. While neither force is in a great position, the one with more ways to avoid a “fatal” tumble into space has the advantage.

  • $\begingroup$ Thank you for your answer although I don't think "pummeling the people until they are mush" is something space police with do but I guess it'll weather you have a tether or not $\endgroup$
    – Qazi Talha
    Mar 23, 2022 at 12:56

Self-propelled bullets

Effectively very small missiles but without the explosive. A small object with its own cold gas thrusters is let go by the attacker (so no recoil). The bullet/drone flies to the target, accelerates, and then hits the target. It does not need to have an explosive payload (though that is an optional extra), the entire damage is caused just the kinetic impact.

Think of it as a rocket propelled punch to the stomach.


For police force.

  1. stun/tasers - any way of electric shock delivery. Use only in rooms with atmosphere.
  2. EMP grenades/emiters - disable electronics and personal life support (heat exchangers, air pumps and so on) make target so obeying...
  3. nets/glue - guns or grenades. If can't move or need lots of strenght to do anything then You lost.
  4. small piercers. Small hole in suit is not lethal but You need to be quick fixed, if not, then You lose all air and be dead.
  5. all above combined - net with shock and EMP emiters and with small thorns to make some holes in suit and glue to fix them released only when pressed right button on police uniform :)
  • $\begingroup$ I didn't think about EMP Emitters at all $\endgroup$
    – Qazi Talha
    Mar 24, 2022 at 6:32

"The Last Deathship Off Antares" by William J. Watkins. The author clearly put a lot of thought into how free-fall martial arts could be done. Might be worth reading for that. (Warning: The plot is very cheesy and contrived. The martial arts stuff is the only reason to read it.)


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