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
Animals in space were also sent into orbit. In November 2011, the Living Interplanetary Flight Experiment on the Fobos-Grunt mission planned to carry tardigrades to Mars and back; however, the mission failed to leave Earth orbit. In October 2012, 32 medaka fish were delivered to the International Space Station by Soyuz TMA-06M for the new Aquatic Habitat in the Kibo module. On 28 January 2013, Iranian news agencies reported that Iran sent a monkey in a "Pishgam" rocket to a height of and retrieved a "shipment". Later Iran's space research website uploaded an 18-minute video. The video was uploaded later on YouTube. In