Several astronauts have noted that their colleagues, after going out to do a spacewalk or EVA (Extravehicular Activity) have come back into the airlock with a very distinct metallic, sulfuric odor on the outside of their space suits.

The spacewalkers themselves don’t notice it, they smell plastic inside the suits. The crew that helps the spacewalkers in and out of the suits notice it, and the smell lingers for a few days. According to Thomas Jones, a three-time spacewalker, “When you repressurize the airlock and get out of your suit, there is a distinct odor of ozone, a faint acrid smell.” He also noted it smells like burnt gunpowder.

I’m willing to bet that the smell is the result of all of the freely floating elements (ranging from hydrogen up to iron) in the solar system and universe that have at found a home in a sparse and scattered layer on the spacesuits’ outer layers. Obviously, we can’t actually smell space itself, but it’s the same concept as being in a room filled with cigarette smoke. The fabric absorbs the particles, and they come inside. It’s an unmistakable smell, and the suit handlers can’t help but notice it. It’s also on the helmets, as well as the metal tools and whatnot, but less noticeable on the hard items. I think it’s a matter of time before someone capitalizes on this idea of smelling the unsmellable.

Keeping my nose clean… for now,
Jeph