Space questions, answered
Why do astronauts float in space?
Not because there's no gravity — there's plenty. Astronauts float because they're in continuous free fall: their spacecraft is falling around Earth as fast as it moves forward, so they never hit the ground.
At the International Space Station's altitude, Earth's gravity is still about 90% as strong as on the ground. What creates weightlessness is orbit itself — the station is falling toward Earth constantly, but moving sideways so fast (about 28,000 km/h) that it keeps missing. Everyone inside falls at the same rate, so they float relative to the walls.
The correct term is 'microgravity', not 'zero gravity'. It's the same thing you feel for a split second at the top of a roller-coaster drop — astronauts just get to feel it continuously.
Why orbit is really about going sideways →The ISS, by the numbers →
People also ask
Is there gravity on the space station?
Yes — about 90% of gravity at the surface. Astronauts float because they're in free fall, not because gravity is absent.
Sources: NASA — microgravity