The International Space Station, or ISS, is a laboratory that orbits Earth about 250 miles above us. It travels at 17,500 miles per hour and circles the planet every 90 minutes. Astronauts from different countries live and work on the ISS for months at a time. They conduct scientific experiments that cannot be done on Earth because there is no gravity in space.
Life on the ISS is very different from life on Earth. Astronauts sleep in sleeping bags attached to walls so they don't float away. They exercise for two hours every day to keep their muscles and bones strong. Food comes in pouches and must be heated before eating. The ISS has been continuously occupied since the year 2000. Scientists on the station study how space affects the human body and test new technologies for future space exploration.