Apollo 9 in early 1969. However, LM problems again prevented it from being ready for the D mission by December, so NASA officials created another mission for Apollo 8 using the Saturn V to launch only the CSM on the first crewed flight to orbit the Moon, and the E mission was cancelled as unnecessary. Slayton asked McDivitt and Borman which mission they preferred to fly; McDivitt wanted to fly the LM, while Borman volunteered for the pioneering lunar flight. Therefore, Slayton swapped the crews, and McDivitt's crew flew Apollo 9. The crew swap also affected who would be the first crew
Canceled Apollo missions Apollo–Soyuz Test Project. Skylab 5 would have been a short 20-day mission to conduct scientific experiments and boost Skylab into a higher orbit. Brand, Lind, and William B. Lenoir (science pilot) would have been the crew. Two complete Saturn Vs went unused after the Apollo program, SA-514 and SA-515, as well as the third stage of the SA-513. SA-513 was the launch vehicle originally planned for the Apollo 18 mission, which was used to launch Skylab. The last complete, unflown Saturn IB, SA-209, kept on standby for a possible Skylab Rescue mission, is on display in the Rocket Garden of