When astronauts return from space walks and remove their helmets, they carry with them a peculiar smell which is hard to interpret. This odour is unique and strange, which the astronauts have described as similar to “seared steak.”
In the words of astronaut Don Pettit, “It is hard to describe this smell. It is definitely not the olfactory equivalent to describing the palate sensations of some new food and tastes like chicken. The best description I can come up with is metallic; a rather pleasant sweet metallic sensation. 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. It reminded me of pleasant sweet smelling welding fumes. That is the smell of space. I noticed that this smell was on their suit, helmet, gloves, and tools. It was more pronounced on fabrics than on metal or plastic surfaces each time when I repressed the airlock, opened the hatch and welcomed two tired workers.”