If you pull the trigger on this, you're ruining someone's day, somewhere and sometime.

Gunnery Chief, from Mass Effect 2

Gunny makes a really good point, there. (Follow link for full quote.) For projectile-based weapons in space, a "miss" is really a "hit" - just not on your intended target, and not necessarily in the very near future. (In fact, maybe not even within your lifetime.) Energy-based weapons may dissipate and fizzle, but a projectile left unattended could have substantial consequences for "innocent bystanders".

Voyager sort-of touches on this, though not particularly addressing weapons, in the episode Friendship One. However, I'd like to know if there's an episode that specifically calls out how Starfleet takes responsibility (or doesn't) for its stray projectile weapons.

In a number of cases throughout Star Trek history, we're shown that it is possible to prematurely detonate missiles or photon torpedoes on-demand. Is it ever stated or shown that there is a safety system to detonate them if they miss an intended target? Is a failure of such system ever highlighted?

NOTE: My personal viewing history currently includes all of TNG, DS9, and VOY, and part of season 1 in ENT. Please use spoiler Markdown appropriately for this.

  • 7
    In general the spent munitions in space problem is only ever dealt with by authors when fan whining about it reaches a certain level of nuisance. In Trek's case my cynicism suspects that other larger issues always soaked up the maximum amount of 'write something just to make them shut up' the writers had. Jan 7, 2013 at 21:23
  • "Weapons range" may be about the target ship's ability to dodge/use countermeasures rather than the weapon's actual range. You have to be close enough to limit the target's ability to respond.
    – Joe L.
    Jan 12, 2015 at 14:59
  • 2
    "Infinite" is non-physical. Long before the heat death of the universe the projectile will have been ablated away, along with its coherent packet of kinetic energy, by collisions with dust and high energy particles at relativistic speeds. Space is not empty and has friction.
    – Lexible
    Mar 6, 2020 at 18:43
  • In the film "First Contact" Picard expresses surprise when a relatively simple weapon, a machine gun (projectile weapon), kills a Borg.
    – user66716
    Mar 6, 2020 at 21:35

2 Answers 2


While it is hard to say what Starfleet would do regarding torpedoes that miss their target in the heat of a battle, they will go after ones that go stray during testing. In the TNG episode Genesis Picard and Data leave the Enterprise in a shuttle craft to take care of a photo torpedo that missed its intended target and was unable to be remotely detonated.


Star Trek never really addresses the issue because there's nothing to address. Projectiles launched at relativistic speeds that miss their targets leave the area in a hurry and basically can be forgotten.

Gunnery Chief was mistaken. Space is big and most significant impacts are caused by gravitational attraction bringing or keeping masses in close proximity rather than random shotgun effects. A 20kg projectile moving at .33c passing a few AU away would barely notice the tug of a neutron star let alone anything people might be living on. Once you launch such a projectile it's gone, pretty much in a straight line until the Big Crunch. Only unimaginably rotten luck would cause such an object to run into anything of planetary size. A stray asteroid or comet is much more likely to have been dragged in and killed everything several times over before such an unlikely event would occur.

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    +1, I don't know why this answer was down voted as it makes an important point. I remember in astrophysics at Uni we did the sums of the chance of stars colliding when whole galaxies crash into each other and the answer is close enough to 0%. That's for objects that both have the size and mass of a freaking star. When you're talking about torpedoes and starships the odds are much lower than that. Space is really really really empty even if scifi writers typically neglect to portray that accurately. Jan 8, 2013 at 4:02
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    @Bogdanovist probably because it invalidates the cool quote in the question :D
    – edgerunner
    Jan 8, 2013 at 9:12
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    +1 Also see physics.stackexchange.com/questions/46189 as it's related. The chance of hitting a star in your home galaxy is of the order of 0.03%. Since planets are much smaller than stars the chance of hitting a planet is negligable. Jan 8, 2013 at 9:12
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    One thing to keep in mind is that self guided projectiles, like a photon torpedo, may lock on to a new target if they are malfunctioning (or jammed). So while the probability of it happening to be in line with a planet or other body in space is extremely remote, the possibility of it causing collateral damage is higher than that calculation alone.
    – Xantec
    Jan 10, 2013 at 19:38
  • 2
    @Xantec: Why? They'll be out of battery in a dozen minutes. No point carrying more battery than you need.
    – Joshua
    Aug 17, 2015 at 17:27

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