Zero Gravity Antics
Photograph courtesy NASA
Skylab 4 commander Gerald Carr balances fellow astronaut William Pogue, the mission's pilot, upside down on his finger in zero gravity. Skylab, America's first space station, was launched into orbit in 1973 as a follow-up to the Apollo program. Three crews visited the station, with their missions lasting 28, 59, and 84 days, respectively.