What does space smell like?

The answer

Astronauts returning from spacewalks consistently describe a distinctive metallic, smoky odor clinging to their suits and equipment. This scent is attributed to polycyclic aromatic hydrocarbons (PAHs), byproducts of dying stars that permeate interstellar space. When these molecules encounter oxygen in the airlock, they produce the characteristic seared steak and gunpowder smell. NASA even commissioned a fragrance chemist to recreate the scent for training purposes. Different regions of space likely have different smells depending on their chemical composition.