- published: 03 Jul 2015
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The International Space Station (ISS) is a habitable artificial satellite in low Earth orbit. It follows the Salyut, Almaz, Skylab and Mir stations as the ninth space station to be inhabited. The ISS is a modular structure whose first component was launched in 1998. Like many artificial satellites, the station can be seen from Earth with the naked eye. The ISS consists of pressurised modules, external trusses, solar arrays and other components. ISS components have been launched by American Space Shuttles as well as Russian Proton and Soyuz rockets. Budget constraints led to the merger of three space station projects with the Japanese Kibō module and Canadian robotics. In 1993 the Soviet/Russian Mir-2, the American Freedom, and the European Columbus merged into a single multinational programme. The Russian Federal Space Agency plans to separate some of its modules from the Russian segment to form the OPSEK facility before the remainder of the station is deorbited.
The ISS serves as a microgravity and space environment research laboratory in which crew members conduct experiments in biology, human biology, physics, astronomy, meteorology and other fields. The station is suited for the testing of spacecraft systems and equipment required for missions to the Moon and Mars.
A space station (or orbital station) is a spacecraft capable of supporting a crew which is designed to remain in space (most commonly in low Earth orbit) for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by lack of major propulsion or landing systems. Instead other vehicles transport people and cargo to and from the station. As of October 2011[update] two space stations are in orbit; the International Space Station, and China's Tiangong 1. Previous stations include the Almaz and Salyut series, Skylab and most recently Mir.
Space stations are used to study the effects of long-term space flight on the human body as well as to provide platforms for greater number and length of scientific studies than available on other space vehicles. All space stations have been designed with the intention of rotating multiple crews, with each crew member staying aboard the station for weeks or months, but rarely more than a year. Since the ill-fated flight of Soyuz 11 to Salyut 1, all manned spaceflight duration records have been set aboard space stations. The duration record for a single spaceflight is 437.7 days, set by Valeriy Polyakov aboard Mir from 1994 to 1995. As of 2011[update], three astronauts have completed single missions of over a year, all aboard Mir.