Harrison Schmitt credits the image to the entire Apollo 17 crew. While on the Moon's surface, Schmitt — the only geologist in the astronaut corps — collected the rock sample designated Troctolite 76535, which has been called "without doubt the most interesting sample returned from the Moon". Among other distinctions, it is the central piece of evidence suggesting that the Moon once possessed an active magnetic field. As he returned to the Lunar Module before Cernan, Schmitt is the next-to-last person to have walked on the Moon's surface. After the completion of Apollo 17, Schmitt played an active role in documenting the
Astronaut-politician and finishing in 6th place. Glenn returned to space on October 29, 1998 aboard Space Shuttle Discovery (STS-95) while still a sitting Senator. The next year he retired from Congress. Two Apollo astronauts were elected to the United States Congress. "Astronaut turned Sen. Harrison 'Jack' Schmitt", whose participation on the Apollo 17 mission made him the only geologist to walk on the Moon, resigned from NASA in August 1975 and shortly thereafter ran as a Republican, winning the New Mexico Senate seat in 1976 over two-term Democratic incumbent, Joseph Montoya by a margin of 57% to 42%, despite being described