The International Space Station (ISS) is a manned, earth-orbiting space station, constructed in earth orbit, using American space shuttle and Russian Proton and Soyuz rocket flights. Now the largest artificial body in orbit, it can often be seen with the naked eye from Earth. The ISS is maintained in an approximately circular orbit, at an altitude between 330 km (205 mi) and 435 km (270 mi), with an inclination of 51.6 degrees.
Zarya (Dawn) was the first-launched of the numerous modules of the ISS. The Russian-built, American-financed Zarya was the initial control module. Also known as the Functional Cargo Block (FGM when the Russian equivalent acronym is transliterated), it was linked together with Unity, the American six-port habitable connection module, in the first assembly step of the ISS. Because Zarya was the first-orbited element of the ISS, its international spacecraft ID (1998-067A) is also the ID used for the International Space Station.
The International Space Station is a large, manned, multi-module earth-orbiting space station, intended for various research and development uses. It was constructed in earth orbit, using STS shuttle flights (U.S.A.) and Proton and Soyuz rocket flights (Russia) for ferrying components into orbit and for later resupply flights. ISS follows the Salyut, Almaz, Skylab and Mir stations as the ninth space station to be inhabited. Now the largest artificial body in orbit, it can often be seen at the appropriate time with the naked eye from Earth.
In 1984, President Ronald Reagan gave NASA the go-ahead to build a space station, and invited the participation of international partners. There was a series of proposed plans for a large manned earth-orbiting space station, at low inclination, to be coordinated with related platforms, such as the ESA Columbus Polar Platform, Columbus Attached Lab, and Columbus Free-flying Platform. Over time, each proposed station and alternative version in turn failed to gain acceptance and budget approval, and was dropped during re-scoping and down-sizing of the plan.
Eventually the multi-nation US-led international station, named International Space Station, or ISS, was accepted and gained U.S. budget approval. By launch time the mission had evolved, due largely to financial constraints, to include a variety of levels of involvement by additional other nations. As of November, 1998 the global participants, in addition to the United States, included Russia, Canada, Japan, Brazil, and ESA (Belgium, Britain, Denmark, France, Germany, Italy, The Netherlands, Norway, Spain, Sweden, and Switzerland). In the first phase of the project, seven U.S. astronauts spent almost 27 months aboard the Russian Mir, gaining technical, operational and risk management experience.
The first two modules of the ISS, Zarya (1998-067A) and Unity (1998-069F, also called Node 1), were attached together in orbit at 02:49 GMT on December 7, 1998. Zarya, a 43,000-pound (~19,500 kg) control module launched November 20 by a Russian Proton rocket, and Unity, a 25,500-pound (~11,600 kg) six-port habitable connection module launched aboard the U.S. STS-88 Space Shuttle on December 3, were linked together by the international crew of STS-88. With the subsequent connection of various power, communication, and data cables, the International Space Station became operational.
Budget constraints led to the merger of three space station projects with the Japanese Kibo 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 program.
The station has been continuously occupied for more than 12 years, having exceeded the previous record of almost 10 years (or 3,634 days) held by Mir, in 2010. 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 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.
The ISS consists of pressurized modules, external trusses, solar arrays and other components. 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 15.7 orbits per day.
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.
The ISS provides a platform to conduct scientific research that cannot be performed in any other way. While small unmanned spacecraft can provide platforms for zero gravity and exposure to space, space stations offer a long term environment where studies can be performed potentially for decades, combined with ready access by human researchers over periods that exceed the capabilities of manned spacecraft.
The ISS crew provide opportunities for students on Earth by running student-developed experiments, making educational demonstrations, allowing for student participation in classroom versions of ISS experiments, and directly engaging students using radio, videolink and email.
Alternate Names
FGB
International Space Station
MKS
Space Station
Unity
Zarya
Facts in Brief
Launch Date: 1998-11-20
Launch Vehicle: Proton-K
Launch Site: Tyuratam (Baikonur Cosmodrome), Kazakhstan
Mass: 31100.0 kg