The ISS, or International Space Station, is a large space station orbiting Earth at about 250 miles (400 kilometers) altitude. It is a multinational cooperative project involving five space agencies: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada)
. The ISS serves as a permanently crewed space laboratory and home in space, continuously inhabited since November 2, 2000. It is used for scientific research in microgravity, studying the effects of space on biology and materials, testing space technologies, and conducting Earth and space observations. The station supports experiments in various fields including physics, biology, and space medicine, and helps prepare for future missions to the Moon and Mars
. The station is composed of pressurized modules for living and working, and unpressurized external structures such as solar arrays and robotic arms. It completes an orbit around Earth roughly every 93 minutes, traveling at about 17,500 mph (28,000 km/h)
. Originally conceived as separate US and Russian stations, the ISS was merged into a single international facility in the 1990s and assembled in orbit starting in 1998. It is the largest human-made structure in space and symbolizes international cooperation in space exploration
. The ISS is expected to remain operational until at least 2030
