Harrison Schmitt gave a lecture at Caltech on August 4, 2026 (Photo – Caltech Astro)
In 1972, Caltech alumnus and former astronaut Harrison Schmitt (BS ’57), the Apollo 17 mission’s lunar module pilot, became the only geologist to walk on the Moon.
By Lori Dajose, Caltech
On August 4, 2026, Schmitt visited campus to give a talk titled “Apollo 17’s History in the Dust.” In introducing Schmitt, Caltech planetary scientist Mike Brown described the Apollo 17 mission as “the most epic field geology that’s ever been accomplished.”
Schmitt, who served as a U.S. senator representing New Mexico from 1977 to 1983 (after 10 years as a NASA astronaut), outlined how billions of years of lunar history can be understood through the Moon’s isotopic signatures. Studying the chemical composition of the ancient dust in the Taurus-Littrow Valley, where the Apollo 17 crew landed, gave clues to how the early Moon’s magma ocean solidified and differentiated, with heavier minerals sinking into the crust.
During the lecture, Schmitt praised Caltech as a “great field geology institution” and expressed his hope for more field geology training for astronauts in NASA’s Artemis lunar exploration program, citing how the benefits of his own training applied to lunar sample collection. Schmitt also emphasized the importance of combining autonomous robotics with human capabilities, saying that only humans can handle the “unknown unknowns”—surprises on a space mission that can’t be predicted.
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