Canceled Apollo missions Schirra's crew would fly the C mission, first manned CSM (Block II CSM-101, retrofitted with the cabin safety improvements) as Apollo 7 in October 1968. McDivitt's crew and mission were kept as the first manned development LM flight (D mission); this was planned to be Apollo 8 in December 1968, now using a single Saturn V launch vehicle instead of two separate Saturn IB launches. The E mission was planned as an elliptical medium Earth orbit test of the operational LM with the CSM in a simulated lunar mission to an apogee of , to be commanded by Frank Borman
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