Smell of Space

 Yes—astronauts really do describe space that way, and it’s one of those weird-but-true details of spaceflight.

Astronauts like Chris Hadfield and Don Pettit have reported that after spacewalks, when they come back into the spacecraft and remove their suits, they notice a distinct smell—often compared to:

• gunpowder
• burnt steak
• welding fumes
• hot metal

Why would space “smell” like that?

Technically, space itself doesn’t have a smell—it’s a vacuum, so there’s no air to carry odors.

The smell actually comes from particles sticking to the astronaut’s suit during a spacewalk. When they re-enter the airlock and repressurize it, those particles react with oxygen and create odors.

The science behind it

Scientists think the smell is caused by:

• Atomic oxygen reactions (highly reactive oxygen in low Earth orbit)
• Polycyclic aromatic hydrocarbons (PAHs) — molecules formed in stars and found in space dust
• Residue from metal oxidation or high-energy particle exposure

These reactions can produce scents similar to:

• seared meat (like cooking reactions on Earth)
• burnt or metallic smells (like welding)

Fun comparison

Interestingly, the “burnt steak” smell may be similar to the same chemical processes that happen when you cook meat—the Maillard reaction, a type of Chemical reaction involving heat and proteins.

Bottom line

Space doesn’t smell on its own—but when astronauts bring a bit of it back on their suits, it creates a surprisingly familiar scent: smoky, metallic, and a little like a cosmic barbecue.

If you want, I can explain what space would taste like (astronauts have opinions on that too 😄).