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Aarwaa · #6 Wednesday, June 06, 2007

Space Station

space station or space platform,artificial earth satellite, usually manned, that is placed in a fixed orbit and can serve as a base for astronomical observations; zero-gravity materials processing; satellite assembly, refueling, and repair; or, possibly, as weapons platforms. The first space station was the Soviet Salyut 1, launched in Apr., 1971. The Soyuz 10 spacecraft docked with this station, but the crew did not enter it; two months later the cosmonauts aboard the Soyuz 11 spacecraft docked and entered Salyut 1, remaining aboard for 22 days. By 1982 five more Salyut space stations had been orbited successfully, two of them for military purposes. By rotating the crews regularly, the Soviets were able to staff the stations for extended periods. All the Salyut space stations have decayed and are no longer in orbit.

During this period the United States launched its only true space station. Called Skylab, it was placed in orbit in May, 1973. Skylab housed three three-person crews, the last remaining aboard for 84 days, which at that time was a record for continuous residency in space. Among the tasks accomplished by the Skylab astronauts were biomedical studies to evaluate the effects of weightlessness, photographing the earth to monitor volcanoes and earthquake faults, astronomical observations of optical sources (including extensive studies of Comet Kohoutek), and materials-processing activities such as brazing and welding (to see how they were affected by the lack of gravity). Skylab fell to earth in July, 1974, showering debris over uninhabited parts of Australia and the Indian Ocean.

The Soviet Union launched the core module of the Mir space station in Feb., 1986. It was enlarged several times so that it could accommodate a crew of up to six cosmonauts. The Mir program was enhanced by having international teams conduct experiments at the station; Afghanistan, Bulgaria, France, Germany, Great Britain, India, Japan, Syria and the United States, in addition to Russia and other nations that were formerly part of the Soviet Union, participated. In 1995, Mir cosmonaut Valery Polyakov set an endurance record of nearly 439 days in space, eclipsing the previous record of 326 days set in 1987 by Yuri Romanenko (also while on Mir). In Aug., 1999, its extended 13-year mission concluded, Mir was abandoned. During its lifetime, it orbited the earth 86,331 times and was home to 104 people, including 42 Russian cosmonauts and 7 American astronauts. In Mar., 2001, Mir fell to earth, the largest spacecraft (143 tons/130 metric tons) ever to decay, showering an estimated 1,500 fragments of 44 lb (20 kg) or more over an uninhabited area 120 mi (193 km) wide by 3,600 mi (5795 km) long in the South Pacific.

The United States, Japan, Canada, Brazil, Russia, and 11 members of the European Space Agency (ESA)—Belgium, Denmark, France, Germany, Italy, the Netherlands, Norway, Spain, Sweden, Switzerland, and the United Kingdom—are developing a space station that is being assembled in space. Each partner will contribute a portion of the complex, called the International Space Station (ISS). For example, of the six laboratories that will be included, three will be provided by Russia, one by the United States, one by Japan, and one by ESA. The first element, Zarya (the control module), was orbited by a Russian Proton rocket in Nov., 1998. A month later the U.S. space shuttle Endeavour initiated the first assembly sequence of the ISS, linking the Unity module, a passageway that will connect living and work areas of the station, to Zarya. In July, 2000, the Russian-built Zvezda service module was mated with the two existing components. The first permanent crew—two Russian cosmonauts and an American astronaut—began living aboard the ISS in Nov., 2000, marking the beginning of what is anticipated to be a continuous human presence. When planned construction is completed, the ISS will be 290 ft (88.5 m) long, have a wingspan of 396 ft (120.7 m), and be 143 ft (43.5 m) tall. Its mass will be nearly a million pounds (454,000 kg), and it will support a crew of seven. The plan involves more than 40 space flights over five years, and at least three space vehicles (the space shuttle, the Russian Soyuz rocket, and the Russian Proton rocket) will deliver the various ISS components to earth orbit. Assembly of the more than 100 components will require a combination of human spacewalks and robot technologies. In preparation for the project, construction tasks were practiced by both Mir and shuttle crews, and during 1995–98 nine dockings of the shuttle with Mir were accomplished.

See P. Bizony, Island in the Sky: The ISS (1996); D. M. Harland, The Mir Space Station: Precursor to Space Colonization (1997); M. D. Cole, International Space Station: A Space Mission (1999).