On January 16, 2013, NASA announced that the European Space Agency would build Orion's service module based on its Automated Transfer Vehicle, so the flight could also be regarded as a test of ESA hardware as well as American.
Apollo 8 - had a similar flight path and was also a mission designed to flight test a Command Service Module beyond Earth orbit, it was crewed by 3 astronauts and was lifted by the Saturn V vehicle in 1968.
Apollo 13 - also flew a similar flight path after sustaining damage in an explosion. The spacecraft remained on a free return trajectory as it passed the moon, and as a result it holds the current absolute altitude record for a manned spacecraft. The mission's commander, Jim Lovell, holds the distinction of having set this record twice, the first time on Apollo 8.