How fast does the ISS travel?
The International Space Station travels at about 28,000 kilometers per hour (17,500 mph). At that speed, it circles Earth about once every 90 minutes.
The ISS orbits at an altitude of about 400 kilometers. To stay in orbit at that height, it must move fast enough that, as it falls toward Earth, the planet's surface curves away beneath it. That speed is about 7.7 kilometers per second, fast enough to cross the United States in roughly ten minutes.
Because it circles Earth about 16 times a day, the crew sees around 16 sunrises and 16 sunsets every 24 hours. The station's speed and orbit mean it passes over about 90 percent of the world's population, allowing many people to see it from the ground.
Keeping it up
Even at 400 kilometers, there is a tiny amount of air that slowly drags the station down. Every few weeks or months, engines on the station or on visiting spacecraft fire to raise its orbit. Without these boosts, the ISS would gradually fall back into the atmosphere.
Did You Know?
Astronauts on the ISS travel about 640,000 kilometers a day, roughly the distance to the Moon and back.