Harrison Schmitt cancelled in September 1970, the community of lunar geologists supporting Apollo felt so strongly about the need to land a professional geologist on the Moon, that they pressured NASA to reassign Schmitt to a remaining flight. As a result, Schmitt was assigned in August 1971 to fly on the last mission, Apollo 17, replacing Joe Engle as Lunar Module Pilot. Schmitt landed on the Moon with commander Gene Cernan in December 1972. Schmitt claims to have taken the photograph of the Earth known as "The Blue Marble", possibly one of the most widely distributed photographic images in existence. NASA officially
Apollo 17 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. 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