Why do astronauts float in space?
The short answer
Inside an orbiting spacecraft such as the International Space Station (ISS), astronauts, the station, and loose objects are all falling around Earth together. Because they move almost the same way, astronauts appear to float.
Is the ISS really falling?
Earth’s gravity still pulls on the ISS. The station is falling toward Earth while also moving very fast along the planet’s surface.
Earth is round, so the ground curves away beneath the station as it moves forward. The ISS keeps missing the ground and going around Earth. This path around a planet is called an orbit.
An object that falls under gravity is in free fall. The people and objects inside the ISS are in free fall along with it.
Why don’t astronauts fall to the floor?
On Earth, gravity pulls us downward, and the floor pushes up to support us. We feel that support as weight.
Inside the ISS, the astronauts and the floor are falling together, so the floor hardly needs to support them. A tool released from someone’s hand keeps moving with the astronaut and appears to float instead of dropping to the floor.
Is there no gravity in space?
No. Earth’s gravity still acts at the ISS. Astronauts seem to float because the people and objects inside the spacecraft are falling along with it, not because gravity has disappeared.
This environment is often called microgravity because astronauts experience very little apparent weight. Small effects from air drag and the spacecraft’s motion can still be present. The name does not mean that Earth’s gravity has disappeared.