U.S. space exploration history on U.S. stamps also the only space station NASA launched alone. The 100-ton space station was in Earth's orbit from 1973 to 1979 and it was visited by crews three times in 1973 and 1974. Circling 50 degrees north and south of the equator at an altitude of , Skylab had an orbital period of 93 minutes. There were a plethora of UV astronomy experiments done during the Skylab lifetime, as well as detailed X-ray studies of the Sun. The station was active until July 11, 1979, when it fell out of orbit. The 10-cent Skylab commemorative stamp first day of release took
International Space Station Space Shuttle to dock to the space station. At that time, the Russian station "Mir" was still inhabited. The ISS remained unmanned for two years, while "Mir" was de-orbited. On 12 July 2000, "Zvezda" was launched into orbit. Preprogrammed commands on board deployed its solar arrays and communications antenna. It then became the passive target for a rendezvous with "Zarya" and "Unity": it maintained a station-keeping orbit while the "Zarya"-"Unity" vehicle performed the rendezvous and docking via ground control and the Russian automated rendezvous and docking system. "Zarya" computer transferred control of the station to "Zvezda" computer soon after docking.