Question- would a tesla coil function in space?

What I think would happen- Tesla coils are basically a high DC voltage arcing through the air, searching for the easiest path to ground. A single coil will just send out sparks that dissipate(depends on the power level) a few inches away from the coil. If there are 2 that are linked, the electricity flows through one to the other.

BUT, in both of these cases, there was one thing present in both of them- atmosphere, which is where I'm concerned. I've heard that tesla coils are used to test for a vacuum, and if nothing happens, then you have a vacuum.

I don't think tesla coils would work in space, but I might be wrong, so somebody either correct or confirm this.

BONUS- If you can, also try and figure out a way maybe they could work as spacecraft weaponry.

  • $\begingroup$ The main problem is that the effect would only be effective for a few feet, maybe 100 feet maximum. Hardly useful in a space war. $\endgroup$
    – Hot Licks
    Commented Aug 2, 2020 at 15:36
  • 1
    $\begingroup$ Tesla coils use electric current. Vacuum is a spectacularly good insulator. This wouldn't work. $\endgroup$ Commented Aug 2, 2020 at 20:08
  • $\begingroup$ Since you're first assuming the weapons belong on a spaceship, why would you not rather ask how many readers might care, even if they did notice? If that truly matters, why not invent Whizwow Coils? $\endgroup$ Commented Aug 2, 2020 at 22:06

2 Answers 2



Tesla coil arcs, like all expressions of electricity, need somewhere to go. The electric arcs they produce aren't aimed, they're attracted to a ground.

Theoretically, if the opposing ship were at a significantly lower electrical potential than your own, that would attract the arc (as long as something else wasn't lower still). However, that's a bit of a gamble, and as soon as your enemy realized what was going on, they'd charge their hulls in the same way that horse fences are charged. The result is that your ship attracts the arcs.

Finally, electrical arcs weaken substantially (or require tremendous amounts of energy) as distance increases. Most arcs would want to be measured in a distance of meters in a space battle where distances are likely to be more along the lines of kilometers (or thousands of kilometers). It's not a particularly efficient weapon.

Please note that the arcs tesla coils produce are not electron beams, which is a directed form of electricity. Check that out — it might be more what you're looking for.

  • $\begingroup$ had no idea those beams existed, but that would definitely work better than tesla coils. any idea how big/small they would have to be to cause damage to a target about a mile away? $\endgroup$ Commented Aug 1, 2020 at 21:46
  • $\begingroup$ @Ceramicmrno0b :-) Nope. The machines I'm used to are part of the semiconductor manufacturing process and are about the size of a refrigerator. Future tech would make that smaller for the same power level (etching metal at micronish sizes). Keep in mind, as an author you needn't (and shouldn't) describe every little detail. That can actually ruin a story. Use a believable tech and leave the devil's details to the devil. $\endgroup$
    – JBH
    Commented Aug 1, 2020 at 21:52
  • $\begingroup$ thanks, this helps a ton. $\endgroup$ Commented Aug 1, 2020 at 21:55
  • 3
    $\begingroup$ As pleased as I am with the green check, please be aware that we recommend giving a question 24 hours before selecting an answer. We have users all over the world and human nature is to lose interest once the award is given out. Someone may suggest an idea that's better than my own. $\endgroup$
    – JBH
    Commented Aug 1, 2020 at 21:56
  • 1
    $\begingroup$ Electrically charging the hull could still be weaponized to repel boarders $\endgroup$
    – Dragongeek
    Commented Aug 2, 2020 at 0:42


Firstly, as JBH mentions, you need to have enemy ship at lower voltage potential for Tesla coil to work. But, even if enemy ship did nothing, because ships are separated by ideal insulator (vacuum), immediately upon start of your Tesla coil discharge, the potentials would equalize and your Tesla coil would stop working before doing any damage.

(you know how birds can sit at uninsulated overhead electrical conductors without any ill effects? They might have different potential at start, but as soon as they touch conductor, they become at same potential, and since they are not connected to ground, there is no electrical loop and no danger)

Additionally, for electric current to flow between two points, not only those points must be at different potentials, but those two points must be connected via electrically conductive material.

For Tesla coil, for electric arc to form between two points, the space in between the points is usually gas, which while normally insulator, becomes conductive due to dielectric breakdown at high enough voltages, so arc can form.

Note: while it is theorized in quantum theory that vacuum itself can also suffer dielectric breakdown (and thus become conductive!) near the Schwinger limit, the energies required are so high that the humanity has not yet been nowhere near advanced to try to produce experiment to confirm this.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .