Schmitt was originally part of the Apollo 15 backup crew and later slated to fly in Apollo 18. When that mission was canceled, Schmitt was moved up to Apollo 17 due to his previous work and studies as a professional geologist.
The Apollo 17 astronaut Harrison Schmitt stands on the edge of an erosional canyon that was used to simulate the large Hadley Rille at the Apollo 15 landing site. (13/21)
