SA-210 Apollo-Soyuz Test Project (ASTP) awaits the launch scheduled on July 15, 1975 on the launch pad at the Kennedy Space Center, the ASTP mission with astronauts Thomas Stafford, Vance Brand, and Donald "Deke" Slayton. 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 .