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
Paper plane launched from space the airplanes thus have made its way home, its journey would have helped to demonstrate the feasibility of slow-speed, low-friction atmospheric reentry. Critics have suggested that even a successful demonstration would lack probative impact beyond the realm of diminutive sheets of folded paper—they can only fall. Supporters countered that the broadening of knowledge was justification enough. Paper plane launched from space Japanese scientists and origami masters considered in 2008 launching a flotilla of paper planes from space. The launch was tentatively slated for 2009 from the International Space Station 250 miles above Earth. However, the planes' developers, Takuo Toda (see