Expedition 1

Expedition 1 turned the International Space Station from an impressive but empty structure into a permanently inhabited home, opening a chapter of continuous human presence in orbit that has now lasted more than two decades without interruption. Commander William Shepherd, a U.S. Navy SEAL turned astronaut, led a crew that included Russian cosmonauts Yuri Gidzenko and Sergei Krikalev, the latter already a veteran of the STS-88 assembly mission two years earlier.

The crew launched aboard a Russian Soyuz spacecraft from the Baikonur Cosmodrome on October 31, 2000, and docked with the station two days later, becoming its first residents. Shepherd, drawing on his military background, requested that the crew be addressed using a callsign, "Alpha," rather than the station's formal name, a suggestion that stuck informally for years even though NASA and its partners had officially settled on "International Space Station."

Over 136 days, Shepherd, Gidzenko, and Krikalev activated station systems, conducted scientific experiments, and welcomed a series of Space Shuttle visits that continued the station's ongoing assembly even as they lived aboard it, including STS-97, which delivered the station's first large solar arrays. The crew's daily routines, adapting Zvezda's Russian-designed living quarters into a functioning long-term home, established practical habits and procedures that shaped how every subsequent expedition crew would live and work aboard the growing station.

Expedition 1 returned to Earth in March 2001 aboard Space Shuttle Discovery, having handed off to Expedition 2 just as future crews would continue doing indefinitely afterward. Their four months in orbit marked the beginning of an unbroken chain of human presence aboard the International Space Station that has continued every single day since, one of the longest sustained achievements in the history of spaceflight.

Expedition 1 began what remains one of the longest unbroken achievements in the history of human spaceflight: continuous human presence in orbit, sustained every single day since November 2000 across dozens of subsequent expedition crews.

The crew's work adapting the station's systems and living quarters for genuine long-term habitation established procedures and daily routines that every future expedition crew built upon, turning early improvisation into the mature operational rhythm the ISS still follows today.

William Shepherd, Yuri Gidzenko, and Sergei Krikalev's four months aboard the station also demonstrated, in practice rather than just in planning documents, that American and Russian crews could live and work together in orbit for extended periods, a foundational proof of concept for the international cooperation that has defined the ISS ever since.