According to the standard Apollo crew rotation, the prime crew for Apollo 13 would have been the backup crew for Apollo 10 with Mercury and Gemini veteran Gordon Cooper in command, Donn F. Eisele as CMP and Edgar Mitchell as LMP. Deke Slayton, NASA’s Director of Flight Crew Operations, never intended to rotate Cooper and Eisele to a prime crew assignment, as both were out of favor – Cooper for his lax attitude towards training, and Eisele for incidents aboard Apollo 7 and an extra-marital affair. He assigned them to the backup crew because no other veteran astronauts were available. Slayton’s original choices for Apollo 13 were Alan Shepard as commander, Stuart Roosa as CMP, and Mitchell as LMP. However, management felt Shepard needed more training time, as he had only recently resumed active status after surgery for an inner ear disorder, and had not flown since 1961. Thus Lovell’s crew (himself, Haise and Ken Mattingly) having all backed up Apollo 11 and slated for Apollo 14, was swapped with Shepard’s.