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 14 his trip aboard Apollo 14. He is the only astronaut from Project Mercury (the original Mercury Seven astronauts) to reach the Moon. Another of the original seven, Gordon Cooper, had (as Apollo 10's backup commander) tentatively been scheduled to command the mission, but according to author Andrew Chaikin, his casual attitude toward training, along with problems with NASA hierarchy (reaching all the way back to the Mercury-Atlas 9 flight), resulted in his removal. The mission was a personal triumph for Shepard, who had battled back from Ménière's disease which grounded him from 1964 to 1968. He and his crew were