First Modules in Orbit

On 20 November 1998, a Russian Proton launch vehicle carried the station's first module into orbit — Zarya, funded by the United States but built in Russia. Two weeks later, the Space Shuttle Endeavour (mission STS-88) attached the American connecting node Unity to it.

Zarya ("Dawn") initially provided power, propulsion and attitude control for the entire nascent station — only later modules took over these functions permanently. Unity, docked on 6 December 1998, became the first of three connecting nodes around which the station continued to grow.