The International Space Station

The International Space Station (ISS) is a modular spacecraft in low Earth orbit, assembled and operated by five partner agencies: NASA, Roscosmos, ESA, JAXA, and CSA. It is the first space station built, maintained, and crewed through international cooperation, and it remains the largest human-made spacecraft ever constructed. The station is divided into two main sections: the Russian Orbital Segment, developed by Roscosmos, and the US Orbital Segment, built by the other four agencies. An Integrated Truss Structure connects the station’s solar panels and radiators to its 16 major pressurized modules, which support scientific research, crew habitation, storage, and spacecraft control. The ISS has eight docking and berthing ports and consists of 43 total modules and elements. Its orbit lies between 51.64° north and south, below the Van Allen radiation belts and most space debris, circling Earth every 93 minutes. With solar arrays, it is as large as a full-sized football field, and its pressurized volume of 1,005 cubic meters is comparable to a Boeing 747 airliner. The station originated from the merger of two earlier plans: the United States’ Space Station Freedom and the Soviet Union’s Mir-2. The first module launched in 1998, and continuous human occupation began with Expedition 1 on 2 November 2000, marking the longest uninterrupted human presence in space. The ISS serves as an orbital laboratory for microgravity research across fields like astrobiology, astronomy, materials science, and human medicine. Notable experiments include the Alpha Magnetic Spectrometer, which searches for dark matter. Future plans include adding a commercial module by Axiom Space. The station is expected to operate until the end of 2030, after which it is planned to be de-orbited, though proposals to move it to a higher orbit have gained congressional support.