NASA's international space station orbits Earth carrying out scientific research about living and working in space. It travels at 5 miles per second and takes 90 minutes to complete each orbit. Its progress can be tracked at SpotTheStation.nasa.gov.
The ISS has been manned by an international crew since 2000. Expeditions usually take six months and are manned by three to six crew members. Research is completed in the space station's laboratories that could not be carried out elsewhere. NASA uses lessons from the research to plan expeditions into deeper space. The ISS is powered by solar arrays and is visible from Earth.