 On May 14, 1973, the last Saturn V launch put the Skylab space station in orbit from Pad 39A.By this time, the Cape Kennedy pads 34 and 37 used for the Saturn IB were decommissioned, so Pad 39B was modified to accommodate the Saturn IB, and used to launch three crewed missions to Skylab that year, as well as the final Apollo spacecraft for the Apollo–Soyuz Test Project in 1975.As the Space Shuttle was being designed, NASA received proposals for building alternative launch-and-landing sites at locations other than KSC, which demanded study.