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
Okno-S on the differences between Okno and Okno-S and what the facility actually consists of. Sean O'Connor says that it only covers the region between and above the Earth, providing information on satellites in geostationary orbit. Something in the FAS sourcebook says that the site has two components. This says that equipment with the GRAU index 60Zh6 covers craft in higher orbits and 59Zh6 and 57Zh6 covers craft in lower orbit.. The whole facility is given the name Object 2327S. Primorsky Krai is mountainous and has other space and astronomical facilities. Krona-N, another military space surveillance facility is near Nakhodka at