<Tr> <Th> Command Module Pilot </Th> <Td_colspan="2"> Ronald E. Evans Only spaceflight </Td> </Tr> <Tr> <Th> Lunar Module Pilot </Th> <Td_colspan="2"> Harrison H. Schmitt Only spaceflight </Td> </Tr> <P> Eugene Cernan, Ronald Evans, and former X-15 pilot Joe Engle were assigned to the backup crew of Apollo 14 . Engle flew sixteen X-15 flights, three of which exceeded the 50 mi (80 km) border of space . Following the rotation pattern that a backup crew would fly as the prime crew three missions later, Cernan, Evans, and Engle would have flown Apollo 17 . Harrison Schmitt served on the backup crew of Apollo 15 and, following the crew rotation cycle, was slated to fly as Lunar Module Pilot on Apollo 18 . However, Apollo 18 was cancelled in September 1970 . Following this decision, the scientific community pressured NASA to assign a geologist to an Apollo landing, as opposed to a pilot trained in geology . In light of this pressure, Harrison Schmitt, a professional geologist, was assigned the Lunar Module Pilot position on Apollo 17 . Scientist - astronaut Curt Michel believed that it was his own decision to resign, after it became clear that he would not be given a flight assignment, that mobilized this action . </P> <P> Subsequent to the decision to assign Schmitt to Apollo 17, there remained the question of which crew (the full backup crew of Apollo 15, Dick Gordon, Vance Brand, and Schmitt, or the backup crew of Apollo 14) would become prime crew of the mission . NASA Director of Flight Crew Operations Deke Slayton ultimately assigned the backup crew of Apollo 14 (Cernan and Evans), along with Schmitt, to the prime crew of Apollo 17 . </P>

When was the last time we had a man on the moon