1QUESTION 1 OF 3
Answer & explanation
The official answer, with Fermi’s reasoning step by step.
Answer & explanation
Official answer
295
people
How to estimate it
Fermi’s official “Napkin math”
The station has had people living on it nonstop since 2000, so about 25 years. How many are up there at once? Six or so, and the crew swaps out about twice a year.
- Years with a crew aboard
- ~25
- Crews per year
- × 2
- People per crew
- × 6
- 25 × 2 × 6
- ≈ 300
Rounded assumptions may give a slightly different estimate. The official answer above is the game’s reference value.
Source calculation & reference
- US astronauts who have visited
- 173
- Visitors from the other 25 countries, 13 private tourists included
- + 122
- 173 + 122, as of July 2026
- = 295 people
Reference cited by Fermi: NASA, International Space Station Visitors by Country (July 2026)
How close was your guess?
Your comparison will appear here.
Compare by ratio: divide the larger number by the smaller one. The closer to 1×, the better.