Star Wars: How Do Lightsabers Work In Space? The Simple Answer Is... They Don't

Contains spoilers for "Ahsoka" Season 1, Episode 3 — "Time to Fly"

"Ahsoka" Episode 3 is called "Time to Fly," and its contents most certainly match the label. After plenty of good, old-fashioned space travel and dogfighting between Ahsoka Tano's (Rosario Dawson) ship and Shin Hati's (Ivanna Sakhno) retinue, the protagonists find themselves in a pickle when the Eye of Sion manages to incapacitate their vessel. In what just might be the most amazing moment of the episode, Ahsoka deals with the situation by putting on a space suit, exiting the ship, and using her patented dual lightsabers to deflect enemy fire and defend her allies while Sabine Wren (Natasha Liu Bordizzo) gets the shuttle back in working order. 

Seeing Ahsoka step on the ship's outer hull and fearlessly confront three approaching enemy fighters is an amazing "oh, it's on now" moment, made all the more exciting by her zero-gravity cartwheel dodges and the fact that she actually manages to destroy one of Hati's ships in the process. Still, there's one little problem about the scene, as far as real-life physics is concerned: Ahsoka's lightsabers absolutely wouldn't work in the vacuum of space ... or anywhere else, for that matter.  

There's a pretty good reason we don't have functional lightsabers in real life. The science behind lightsabers is just as complex as every other bit of "Star Wars" lore out there, but it ultimately boils down to magic laser swords that are fueled by magic rocks called kyber crystals, which Force users magically wield to magical effect. Seeing as this doesn't really adhere to basic physics in any way, there's no realistic way of a lightsaber working in space ... but, fortunately, "Star Wars" isn't exactly famous for its dedication to gritty realism.

That being said, it must be noted that the "Star Wars" universe runs on suspension of disbelief — and since various corners of the franchise have clearly shown lightsabers working just fine both underwater and in a vacuum environment, the franchise's ever-sturdy lore has figured out a way to circumvent pesky real-life physics.

Lightsabers consist of a handful of core parts and a bunch of customizable bells and whistles. Inside a hilt casing, a power cell provides the requisite juice, a lens focuses plasma energy through an emitter, and the kyber crystal inside provides the magical oomph for it all by bonding with a Force-sensitive user and focusing the device's energies into a blade. Since the construct comes with its own fuel source, is able to maintain the shape of the plasma blade, and doesn't require interaction with external elements to function, there's no in-universe reason why it wouldn't work in the vacuum of space as long as the fuel source lasts, no matter what real-life physics have to say about it. 

Interestingly, water is a far bigger problem for lightsabers. The weapon can potentially short out underwater, which has led to the creation of a waterproofing upgrade known as bifurcating cyclical-ignition pulse. This extra modification effectively waterproofs the lightsaber and several prominent weapons have this upgrade — including Ahsoka's sabers.  

In real life, heating and containing plasma can be a complex and unwieldy affair (via Science Museum), so the clashing, blaster fire-parrying, all-cutting, fuel-efficient lightsabers the way "Star Wars" depicts them are pretty much impossible. Still, the franchise has come up with a pretty neat way to explain away the weapon's inner workings, and since lightsabers are easily one of the coolest sci-fi gadgets out there, fans probably shouldn't wonder about its real-world plausibility all that much.