“The Surprising Truth About What Outer Space Smells Like” [Mental Floss]:
outer space does have a smell, or rather, many smells. The cosmos isn’t sterile or empty, after all. It’s a quite literally unearthly patchwork of dying stars that shed clouds of pungent soot as well as gases, radiation, and plasma blown about by comets that whiz by at mind-blowing speeds.
All of this, unsurprisingly, comes together to form quite the collision of odors. Much of what scientists believe that space smells like is based on how some of the materials found in space smell on Earth. But there’s one scent that astronauts overwhelmingly report detecting on their gear after coming home from space time and time again, and it’s a strong one.
The main scent that astronauts report smelling upon returning from outer space is a distinctly metallic odor that some have likened to ozone, gunpowder, seared steak, or “sweet-smelling welding fumes,” per NASA. “To me, space smells like a mixture between walnuts and the brake pads of my motorbike,” astronaut Alexander Gerst wrote on Twitter. Many astronauts detect this scent on their suits and equipment following a jaunt in the cosmos.
Some space veterans seemed to find this scent quite pleasant. …”The best description I can come up with is metallic; a rather pleasant sweet metallic sensation,” astronaut Don Pettit wrote. “It reminded me of my college summers where I labored for many hours with an arc welding torch repairing heavy equipment for a small logging outfit,” Pettit continued. “It reminded me of pleasant sweet-smelling welding fumes. That is the smell of space.”
Never occurred to me that space could have an odor, but odor is particles, after all. Space is not empty!
A character in Azimov's Foundation series...