International Space Station (ISS)
The International Space Station (ISS) is an internationally developed research facility currently being assembled in Low Earth Orbit. On-orbit construction of the station began in 1998 and is scheduled to be complete by 2011, with operations continuing until at least 2015.[6] The ISS orbits at an altitude of approximately 350 kilometres (220 mi) above the surface of the Earth,[7][8][9] travelling at an average speed of 27,724 kilometres (17,227 mi) per hour, completing 15.7 orbits per day.[7] The station can be seen from the Earth with the naked eye,[10] and, as of 2009, is the largest artificial satellite in Earth orbit, with a mass larger than that of any previousspace station.[11]
The ISS is a joint project among the space agencies of the United States (National Aeronautics and Space Administration—NASA), Russia (Russian Federal Space Agency—RKA), Japan (Japan Aerospace Exploration Agency—JAXA), Canada (Canadian Space Agency—CSA) and ten European nations (European Space Agency—ESA).[12][a] The Brazilian Space Agency (AEB) participates through a separate contract with NASA.[13] The Italian Space Agency (ASI) similarly has separate contracts for various activities not done within the framework of ESA's ISS projects (where Italy also fully participates).[14] China has reportedly expressed interest in the project, especially if it would be able to work with the RKA, although as of 2009 it is not involved because of objections from the United States.[15][16]
The ISS has been continuously staffed since the first resident crew, Expedition 1, entered the station on 2 November 2000. This has provided an uninterrupted human presence in space for the last 8 years, 328 days.[17] Prior to May 2009, the station had the capacity for a crew of three. However, to fulfil an active research programme, since the arrival of Expedition 20, it has been staffed by a resident crew of six. The crew of Expedition 20 is currently aboard.[18][19] Resident crews utilise the station as an orbital laboratory, carrying out research across a wide variety of fields, including biology, human biology, physics, astronomy and meteorology.[20][21] The station also provides a safe testing location for efficient, reliable spacecraft systems that will be required for long-duration missions to the Moon and Mars.[22]
The station consists of a number of pressurised modules and unpressurised components, which have been launched by Space Shuttle, Soyuz rocket or Proton rocket. The ISS is serviced by a wide variety of manned and unmanned spacecraft, including the Soyuz spacecraft, Progressspacecraft, Space Shuttle, Automated Transfer Vehicle, and H-II Transfer Vehicle, and has been visited by astronauts and cosmonauts from 16 different nations. The various sections of the station are controlled by several mission control centres on the ground, including MCC-H, TsUP,Col-CC, ATV-CC, JEM-CC, HTV-CC and MSS-CC.[23]
