SA-206 lifts off from Kennedy Space Center's launch complex 39B, in Florida, on May 25, 1973, for the first manned Skylab mission (SL-2) with astronauts Pete Conrad, Joseph Kerwin, and Paul Weitz. The Saturn IB, developed under the direction of the Marshall Space Flight Center (MSFC), launched five manned Earth-orbital missions between 1968 and 1975: Apollo 7, Skylab 2, Skylab 3, Skylab 4, and the Apollo-Soyuz Test Project (ASTP).