International Space Station

The International Space Station is the largest structure humans have ever assembled in orbit and the most ambitious peacetime engineering collaboration in history. A partnership of five space agencies — NASA, Roscosmos, ESA, JAXA, and CSA — it circles Earth roughly every 93 minutes at 400 km altitude. Crews of typically seven astronauts run microgravity science, medical research, and Earth observation around the clock. Since November 2000, the station has hosted an unbroken human presence — a 25-year streak that has become quietly historic.

The ISS is built around a 109-metre integrated truss carrying eight massive solar array wings. Pressurised volume is distributed across more than a dozen interconnected modules — Russian segments Zarya, Zvezda, and Nauka; American Destiny, Unity, Harmony, and Tranquility; ESA's Columbus laboratory; and JAXA's Kibo complex with its external exposed facility. Visiting Crew Dragons, Soyuz, Cygnus, Progress, and HTV-X freighters dock through multiple ports.

Construction began with Zarya in November 1998; Expedition 1 boarded in November 2000, beginning the continuous-crew era. More than 270 individuals from 23 countries have visited. The station has hosted thousands of investigations — protein crystallography, cardiovascular studies, plant biology, AMS-02 cosmic-ray physics — that feed both Earth medicine and deep-space mission planning. NASA has contracted SpaceX to build a US Deorbit Vehicle that will guide the ISS to a controlled Pacific reentry around 2031.