The Smell of Space
Astronauts coming in from spacewalks say space has a smell, like seared steak, hot metal or welding fumes.
What was reported
Space is a vacuum, so there's nothing to smell out there. But astronauts who have just come back inside after a spacewalk often notice a distinctive odour clinging to their suits, helmets and tools as the airlock fills with air again.
They describe it as like seared steak, hot metal, burnt almond biscuits or the fumes from welding, and many remember it long after they come home.
Explanations offered
Suggested explanations include atomic oxygen, which is common in low orbit, clinging to suits and reacting with the air in the airlock, and compounds called polycyclic aromatic hydrocarbons, which form in dying stars and are also found in burnt food. The exact cause hasn't been settled.
- When
- Reported since the 1960s
- Where
- Aboard the International Space Station
- Witnesses
- Astronauts returning from spacewalks
- Status
- Partly explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.