Apollo 20 - The Dark side of the Moon Mission

Apolo 20 was originally planned in July 1969 to land in Crater Copernicus, a spectacular large crater impact area. Later Copernicus was assigned to Apollo 19, and the preferred landing site for Apollo 20 was the Marius Hills, or, if the operational constraints were relaxed, the bright crater Tycho. The planned December 1972 flight was cancelled on January 4, 1970, before any crew assignments were made. Or was it? Conspiracy theories believe they were sent for alien ship recovery.