The International Space Station (ISS) is a low-orbit space station that began its assembly in 1998 and has continued to add new modules as recently as 2021. The station is a collaborative project by the space agencies of five geopolitical entities: the United States, Russia, Europe, Japan, and Canada. The main purpose of the station is to conduct experiments on conditions relating to long-term space travel and habitation, such as microgravity. The collaboration between the five agencies also fosters diplomatic relations between their contractors.

The ISS was initially conceived as a joint mission by the United States and Russia in 1993. Following the end of the Cold War and economic difficulties in both countries, the two nations began to explore opportunities for their respective space agencies, NASA and Roscosmos, to achieve mutual goals for space exploration. Although the foundational modules for the station were launched at the end of 1998, it wasn’t until 2000 that Russia launched the modules that would enable sustained life support for human crews. This paved the way for the arrival of the first long-term human presence on the station, Expedition 1, comprised of one American astronaut, William Shepherd, and two Russian cosmonauts, Yuri Gidzenko and Sergei Krikalev.