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
Space Station Freedom Space Station Freedom Space Station "Freedom" was a NASA project to construct a permanently manned Earth-orbiting space station in the 1980s. Although approved by then-president Ronald Reagan and announced in the 1984 State of the Union address, "Freedom" was never constructed or completed as originally designed, and after several cutbacks, the project evolved into the International Space Station program. As the Apollo program began to wind down in the late 1960s, there were numerous proposals for what should follow it. Of the many proposals, large and small, three major themes began to gain currency. Foremost among them was a manned