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
Apollo 7 for 21 months, while the cause of the accident was investigated and improvements made to the spacecraft and safety procedures, and unmanned test flights of the Saturn V rocket and Apollo Lunar Module were made. Apollo 7 fulfilled Apollo 1's mission of testing the Apollo command and service module (CSM) in low Earth orbit. The Apollo 7 crew was commanded by Walter M. Schirra, with senior pilot / navigator Donn F. Eisele, and pilot / systems engineer R. Walter Cunningham. Official crew titles were made consistent with those that would be used for the manned lunar landing missions: Eisele was