Canceled Apollo missions planning their own circumlunar flight for December to upstage the Americans once again (see Zond program). McDivitt's crew—who had grown accustomed to working with LM-3 and preparing for its flight—was kept on the D mission which now became Apollo 9, while Borman's crew would fly the CSM lunar orbit mission on Apollo 8, and the E mission was canceled. The swap of crews was also decisive in who would be the first man to walk on the Moon. Pete Conrad was backup Commander for McDivitt's crew, and by the process of crew rotation, would have been in line for Commander
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