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. Now the largest artificial body in orbit, it can often be seen at the appropriate time with the naked eye from Earth. 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 partially built components for a Soviet/Russian space station Mir-2, the proposed American Freedom, and the proposed European Columbus merged into a single multinational programme. The ISS is arguably the most expensive single item ever constructed.
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.
Since the arrival of Expedition 1 on November 2, 2000, the station has been continuously occupied for 12 years and 287 days, currently the longest continuous human presence in space. (In 2010, the station surpassed the previous record of almost 10 years (or 3,634 days) held by Mir.) The station is serviced by Soyuz spacecraft, Progress spacecraft, the Automated Transfer Vehicle, the H-II Transfer Vehicle, and the Dragon spacecraft. It has been visited by astronauts and cosmonauts from 15 different nations.
The ISS programme is a joint project among five participating space agencies: NASA, the Russian Federal Space Agency, JAXA, ESA, and CSA. The ownership and use of the space station is established by intergovernmental treaties and agreements. The station is divided into two sections, the Russian orbital segment (ROS) and the United States orbital segment (USOS), which is shared by many nations. The ISS is maintained at an orbital altitude of between 330 km (205 mi) and 435 km (270 mi). It completes 15.50 orbits per day. The ISS is funded until 2020, and may operate until 2028. The Russian Federal Space Agency (RSA/RKA) has proposed using ISS to commission modules for a new space station, called OPSEK, before the remainder of the ISS is de-orbited.
· 6 years ago