Mir was the first space station assembled in orbit from multiple modules.
The Soviet Union launched Mir’s core module on 20 February 1986. Unlike earlier stations that operated as largely single structures, Mir was designed as a modular complex. Additional modules were launched separately and attached in orbit, expanding the station’s laboratories, living areas and docking capabilities.
Mir supported long-duration research and hosted crews from several countries. Its modular design and long operational life provided important experience for later international construction in orbit. The station also became the setting for the Shuttle–Mir program, which brought NASA astronauts to the Russian station during the 1990s.
Skylab was the United States’ first space station, but it was launched as one major workshop. The International Space Station was also assembled from modules, beginning in 1998, after Mir had already demonstrated the approach.