Harrison Hagan "Jack" Schmitt (born July 3, 1935) is an American geologist, former NASA astronaut, university professor, and former U.S. senator from New Mexico. He is the most recent living person—and only person without a background in military aviation—to have walked on the Moon.
In December 1972, as a crewmember of Apollo 17, Schmitt became the first member of NASA's first scientist-astronaut group to fly in space. As Apollo 17 was the last of the Apollo missions, he also became the twelfth and second-youngest person to set foot on the Moon and the second-to-last person to step off of the Moon (he boarded the Lunar Module shortly before commander Eugene Cernan). Schmitt also remains the only professional scientist to have flown beyond low Earth orbit and to have visited the Moon. Before training for Apollo 17, he was influential in the geology field for supporting the Apollo program and had helped train Apollo astronauts chosen to visit the lunar surface.