The most complex international engineering project in history — 42 assembly flights, 16 pressurised modules, 420 tonnes, and continuous human habitation since November 2000.
Last updated: · · Sources: NASA, ESA, JAXA, CSA, Roscosmos
The International Space Station is the largest human-made structure ever placed in orbit. Assembling it required over 40 flights — 37 by the Space Shuttle, plus Russian Proton and Soyuz launches — spanning more than a decade from the launch of the Zarya module in November 1998 to the final major US element (the Alpha Magnetic Spectrometer) delivered by STS-134 in May 2011.
The station is a partnership of five space agencies: NASA (United States), Roscosmos (Russia), ESA (Europe), JAXA (Japan), and CSA (Canada). It orbits at approximately 408 km altitude with an inclination of 51.6°, completing one orbit every ~93 minutes. At 109 metres across (wider than a football field) and 420 tonnes, it is visible to the naked eye from the ground as one of the brightest objects in the night sky.
Since 2 November 2000, the ISS has been continuously occupied — the longest uninterrupted human presence in space. Over 280 people from 22 countries have visited the station. It hosts hundreds of experiments in microgravity science, biology, physics, astronomy, and technology demonstration. The station is currently expected to operate until 2030, when NASA plans to deorbit it using a purpose-built spacecraft.
20 Nov 1998: Zarya FGB module launched on a Russian Proton rocket — the first ISS element in orbit.
4 Dec 1998: Unity (Node 1) launched on STS-88 and connected to Zarya — the first assembly mission.
2 Nov 2000: Expedition 1 crew (Shepherd, Gidzenko, Krikalev) arrives aboard Soyuz TM-31 — continuous habitation begins.
7 Feb 2001: Destiny laboratory module installed via STS-98 — the primary US research facility.
2008–2009: Kibo (JAXA) and Columbus (ESA) laboratories installed, expanding the station to six-person crews.
19 May 2011: AMS-02 delivered on STS-134 — the final major US-side assembly flight.
2020–present: Nauka (Russia) and commercial crew vehicles (SpaceX Dragon, Boeing Starliner) expand station capability.