The final frontier smells a lot like a Nascar race—a bouquet of hot metal, diesel fumes and barbecue. The source? Dying stars, mostly. Though a pure, unadulterated whiff of outer space is impossible for humans (it’s a vacuum after all; we would die if we tried), when astronauts are outside the ISS, space-borne compounds adhere to their suits and hitch a ride back into the station. Astronauts have reported smelling “burned” or “fried” steak after a space walk, and they aren’t just dreaming of a home-cooked meal. The smell of space is so distinct that, three years ago, NASA reached...