I know from here that a flame thrower can operate in deep space if specially built. However, I want to know if using a flamethrower on a spaceship in space could have any tactical benefits. Could a flamethrower be used to destroy or blind enemy sensors from several kilometers away, or would it burn out? Would it be possible to build a flamethrower that can reach targets several kilometers away in space?

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    $\begingroup$ Why would you want this? Are standard particle weapons not good for everyone anymore? $\endgroup$
    – AngelPray
    Feb 26, 2017 at 1:15
  • $\begingroup$ @AngelPray Some prefer a less technological approach $\endgroup$ Feb 26, 2017 at 1:16
  • $\begingroup$ I think the answer sufficiently point out why it's a bad idea as a ship-to-ship weapon. Conversely, it's an ideal weapon for a boarding party, imo, as borne out by a number of movies and games. $\endgroup$
    – Paul
    Feb 26, 2017 at 19:21
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    $\begingroup$ @Paul No, actually it's a terrible idea for a boarding party unless the boarders don't need to breathe and are immune to fire, as borne out by the safety manual for every submarine ever made. Fire is pretty much the worst thing that can happen in a giant sealed metal can full of pressurized air. $\endgroup$ Feb 26, 2017 at 21:53
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    $\begingroup$ Let us continue this discussion in chat. $\endgroup$ Feb 27, 2017 at 12:16

5 Answers 5



Improper Usage

Remember that the purpose of a flamethrower is to set flammable targets on fire like wood structures and humans and to consume oxygen from enclosed spaces. It is safe to assume that spaceships will not be made out of flammable materials. Ships are sealed so that they do not lose oxygen to space, so unless the flamethrower can penetrate the hull it will not harm the air inside the ship. There are also far more effective methods to blind enemy sensors than generating a lot of heat and IR. Space ships already are going to be able to filter out far hotter things from their sensors like near by stars.

Distance and Velocity

For a flame thrower to travel one kilometer it would need to ignite at the end of the stream on impact otherwise it will burn its fuel off before it got to the target.

Flamethrowers also run into an issue that the fluid is not going to be moving that fast compared to other weapons so enemies will easily see it coming and avoid it. You can switch it out for an incendiary missile, which will get the payload to its target faster, but it will cease to be a flamethrower at that point.

Armor and Shields

Space ships are going to be designed to handle far worse than what a flamethrower can dish out. Flamethrowers are a chemical based weapon and so they generate energy through chemical reaction. However, there are a large number of weapons out there that can generate far more destructive forms of energy, and as such space ship defenses will be designed to handle those types of things. So when the flamethrower hits the shields or armor at the worst it will likely only damage the paint job.

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    $\begingroup$ +1 for this post, but I will mention that another tactical use of Flamethrowers was to consume the Oxygen in fortifications. $\endgroup$
    – Sarriesfan
    Feb 26, 2017 at 8:14
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    $\begingroup$ And any craft capable of atmospheric flight will be explicitly designed to handle worse temperature. The only use I can imagine is if for some reason nanodust swarm clouds become weaponrised. Then flamethrowers would be a good point defence against them. Keep in mind that in vacuum such swarm couldn't manoeuvre so it would have to be released by ships, hoping enemy can't detect it until too late, or as payload by missile. Flamethrowers would provide good last line of defence when it's already too late to dodge. $\endgroup$
    – M i ech
    Feb 26, 2017 at 10:32
  • $\begingroup$ @Sarriesfan yes I forgot that one, I will add it to the list. $\endgroup$
    – Anketam
    Feb 26, 2017 at 11:55
  • $\begingroup$ This. I think what he's looking for are plasma based weapon systems. Fire in space just doesn't make sense. The OP also seem to be unaware that space combat will take place at more than just many miles away. In the void you could potentially engage enemies at thousands if not hundred-thousand miles away. When you will get close enough to use fire you are already dead. $\endgroup$
    – r41n
    Feb 27, 2017 at 10:44
  • $\begingroup$ Fire in space makes sense if you have an oxidizer. You can find ways to increase flamethrower range to a few kilometers, and somehow find a way to ignite the stream of fuel and oxidizer. You could even just put fuel and oxidizer in shells and fire them. $\endgroup$ Feb 27, 2017 at 12:34

Why would you do this? Usually space weapons are high energy high velocity.

There's benefit to utterly unexpected tactics. Flamethrower won't work for practical reasons, but how about some super caustic thermite goo?

"Sir, incoming" "Missile?" "Nope, too slow, no evidence of a guidance system" "Impact danger?" "Low mass and velocity, no danger of hull breeach" "Hold course, ready main missile batteries, energy weapons and rail guns." "Ready... wait, hull sensors in the area of impact are starting to go down" "Damage control teams to affected decks. What is it?" "It's goo, wait, now it's on fire, hull breech warning on decks three and seven, also four. Now five and six." "Fire control teams, seal all decks prepare for depressurization"

Bam. Goo wins the day.

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    $\begingroup$ The advantage of thermite being that it does neither require nor produce any gases, just juicy white-hot iron. $\endgroup$ Feb 26, 2017 at 12:41
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    $\begingroup$ For this to be an effective tactic, you'll probably want to send out a whole lot of projectiles, with most of them being just cheap light empty decoy shells, so it's impractical for the target ship to just destroy all of them from afar to be safe. $\endgroup$ Feb 26, 2017 at 12:47
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    $\begingroup$ So... they can detect an incoming projectile ... and they just shrug it off because they think it's not insanely hot? How did they detect it and not notice the temperature? $\endgroup$ Feb 27, 2017 at 5:26
  • $\begingroup$ What @JanDvorak said. A gentle nudge with maneuvering thrusters would most likely be all you need to move out of the projectile's path, particularly if it is unguided; not doing so would be the bad choice, even if you think the risk is small. Let alone that a small projectile could also pack quite a punch. Also, keep in mind that velocity is a relative quantity. Remember: Action should generally be proportional to risk (of impact, say) multiplied by potential effect (you're in a combat situation, so it's reasonable to expect anything incoming to be potentially capable of doing harm). $\endgroup$
    – user
    Feb 27, 2017 at 12:47
  • $\begingroup$ I was going to reply with something like this. You can't shoot fire in space, but you can shoot something like "fire ingredients" that will activate when in contact with the ship's material and atmosphere. $\endgroup$
    – ecc
    Feb 27, 2017 at 12:49

A flamethrower is, fundamentally, a device that ejects burning-hot stuff at a moderate-to-fast speed.

A rocket is a device that ejects stuff at very fast speeds, and the stuff it ejects tends to be burning-hot (since that's a very effective way to make fast-moving exhaust).

If for some reason a spaceship builder decided to put a flamethrower on the outside of their ship, especially if it needs a range of several kilometers, it seems likely that it would be based on a backwards-facing rocket more than a traditional earthbound flamethrower. What you'd be looking at there would be weaponized exhaust - along with some (possibly rather significant) acceleration away from the target.

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    $\begingroup$ Or just use the actual rocket engine on your ship: tvtropes.org/pmwiki/pmwiki.php/Main/WeaponizedExhaust $\endgroup$
    – Salda007
    Feb 26, 2017 at 8:12
  • $\begingroup$ Yep, pretty much. I figured I'd avoid a TVTropes link, but I can edit that in if you think it would improve the answer. $\endgroup$
    – Soron
    Feb 26, 2017 at 8:24
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    $\begingroup$ TVTropes links are more often helpful than not on this site, since tropes are a major part of worldbuilding. $\endgroup$
    – March Ho
    Feb 26, 2017 at 14:06

What you're essentially looking for is something that's fuel and oxidizer. White Phosporous's probably the good stuff. Add an oxidiser since space dosen't typically have an atmosphere, and something thick and sticky to carry it all and stick to surfaces, since there's no gravity in space. Maybe encapsulate the two chemicals so they don't react prematurely in heat-decomposing "cells". Since its space, lauching it as a stream makes no sense. Instead have them in canisters with an igniter that kickstarts the combustion. Launch them have them hit and splash on a target - vaguely like a HESH round then sets the fuel, which is stuck to the target on fire

Since space craft have limited capacity to dump out heat, this might actually end up being pretty nasty. It would be a complicated/rube goldbergian weapon though

You could also use them as decoys or flares as needed. However, I do suspect something like this wouldn't be as effective in most cases as big, dumb, fast projectiles, except against say a space station or other stationary target.


You could use a flamethrower inside as spaceship to devastating effect if a flamethrower is specifically what you want. However, if you want to attach a flamethrower to a spaceship that would not be the most effective use of a flamethrower or a spaceship. If you absolutely need to use a flamethrower in space consider drones. Drones can reach high velocities and hit enemy ships super far away. Then you might get some practical use. Particle cannons, missiles, and railguns are still probably more effective, though... I hope that was helpful!


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