Mattingly had been scheduled to fly on the ill-fated Apollo 13 mission, but three days prior to launch, he was held back and replaced by Jack Swigert due to exposure to German measles (which Mattingly did not contract). Mattingly later flew as Command Module Pilot for Apollo 16 and made 64 lunar orbits, making him one of 24 people to have flown to the Moon. Mattingly and his commander from Apollo 16, John Young, are the only people to have flown to the Moon and also a Space Shuttle orbital mission (Fred Haise, his former training crewmate from Apollo 13, did atmospheric flight testing of the Space Shuttle Approach and Landing Tests).