Harrison Hagan "Jack" Schmitt (born July 3, 1935) is an American geologist, former NASA astronaut, university professor, former U.S. senator from New Mexico, and the most recent living person—and only person without a background in military aviation—to have walked on the Moon.

Born July 3, 1935,[5] in Santa Rita, New Mexico, Schmitt grew up in nearby Silver City,[6] and is a graduate of the Western High School (Class of 1953).

As a result, Schmitt was assigned in August 1971 to fly on Apollo 17, replacing Joe Engle as Lunar Module Pilot.

[18] On April 29, 2018, the Schmitt Space Communicator SC-1x named in his honor was carried aboard the Blue Origin New Shepard crew capsule[19][20] in a project partly funded by NASA.

[23][24] The three-pound (1.4 kg) device was developed by Solstar, which Schmitt had joined as an advisor, and launched 66 miles (106 km) above the Earth's surface, just past the edge of space, as a technology demonstration.

[31] He served one term and, notably, was the chairman of the Science, Technology, and Space Subcommittee of the United States Senate Committee on Commerce.

Bingaman criticized Schmitt for not paying enough attention to local matters; his campaign slogan asked, "What on Earth has he done for you lately?

Schmitt is an adjunct professor of engineering physics at the University of Wisconsin–Madison,[35] and has long been a proponent of lunar resource utilization.

[39] In November 2008, he quit the Planetary Society over policy advocacy differences, citing the organization's statements on "focusing on Mars as the driving goal of human spaceflight" (Schmitt said that going back to the Moon would speed progress toward a crewed Mars mission), on "accelerating research into global climate change through more comprehensive Earth observations" (Schmitt voiced objections to the notion of a present "scientific consensus" on climate change as any policy guide), and on international cooperation (which he felt would retard rather than accelerate progress), among other points of divergence.

[40] Schmitt also serves as a visiting senior research scientist at the Florida Institute for Human & Machine Cognition.

[43] Schmitt wrote a book entitled Return to the Moon: Exploration, Enterprise, and Energy in the Human Settlement of Space in 2006.

[40] Schmitt resigned from the Planetary Society due to disagreements over their "Roadmap to Space Exploration", which recommended prioritizing earlier human missions to Mars over U.S. lunar expeditions.

"[52] In 2013, Schmitt co-authored an opinion column in The Wall Street Journal with William Happer, contending that increasing levels of carbon dioxide in the atmosphere are not significantly correlated with global warming, attributing the "single-minded demonization of this natural and essential atmospheric gas" to advocates of government control of energy production.