How do we know?
↻ One of the pages with a moving picture
A special plane lets people float, just for a little while.
- Earth’s gravity pulls the space station down toward Earth.
- But the station also zooms sideways, about 5 miles every second!
- So it keeps falling around Earth instead of into it. This is an orbit.
- The astronauts fall right along with the station, so they float inside it.
Airplanes can make floating too! A special plane flies up and down in big arcs. For about 20 seconds at a time, everyone inside falls together and floats.
It is the same trick the station plays, only much shorter. Astronauts also practice spacewalks underwater at NASA in Houston, in a pool holding 6.2 million gallons.
And the station really is never empty: crews arrive on rockets such as Soyuz from Baikonur in Kazakhstan.
Wow number
16 sunrises and 16 sunsets: that’s what astronauts on the station see every 24 hours!
Myth or fact?
There’s no gravity on the space station. Myth. Gravity there is about 90% as strong as on the ground.
People have lived on the station every day since November 2000. Fact. It’s never empty!
Think about it
The Moon falls around Earth too. How is the Moon like the space station?
Where in the world?
Baikonur Cosmodrome, Kazakhstan where Soyuz rockets carry crews to the station. In Houston, Texas, astronauts practice spacewalks in a pool holding 6.2 million gallons — 45.965° N, 63.305° E.
Where these facts come from
Every number on page 13, and who measured it
This page explains that astronauts float because they are falling around Earth.
What Is Microgravity? (Grades 5-8) — NASA, the U.S. space agency
nasa.gov/learning-resources/for-kids-and-students/what-is-microgravity-grades-5-8
We checked it on 31 October 2026
This page tells us how fast the station goes and how many sunrises astronauts see.
International Space Station Facts and Figures — NASA, the U.S. space agency
nasa.gov/international-space-station/space-station-facts-and-figures
We checked it on 31 October 2026
This page tells us about a crew blasting off from Baikonur in Kazakhstan.
New Crew Lifts Off Aboard Soyuz Rocket Toward Station — NASA, the U.S. space agency
nasa.gov/blogs/spacestation/2025/04/08/new-crew-lifts-off-aboard-soyuz-rocket-toward-station
We checked it on 31 October 2026
This page tells us about the giant pool where astronauts practice spacewalks.
Neutral Buoyancy Laboratory — NASA, the U.S. space agency
nasa.gov/johnson/neutral-buoyancy-laboratory
We checked it on 31 October 2026
This page tells us how special airplane flights let people float for a short time.
Parabolic Flight — NASA, the U.S. space agency
nasa.gov/mission/parabolic-flight
We checked it on 31 October 2026
Has this changed?
Astronauts have floated in the station for years, so the answer is not going to change.
What changes is who is up there. New crews arrive and old crews come home, so the station is lived in all the time.
Words from this page
- orbit
- The curved path of something that keeps falling around a planet or star.
- gravity
- The pull that every object has on other objects. Big things, like planets, pull hard.
Try it!
Show that falling things float, with a paper cup.
1. Outdoors, have a grown-up poke a small hole near the bottom of a paper cup. 2. Fill the cup with water and hold it up. Watch it leak. 3. Now drop the cup.
What happens: while the cup falls, the water stops leaking! Cup and water fall together, like astronauts and their station.
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