All of the astronauts who landed on the moon were trained in geology, and Apollo 17's geologist-astronaut Jack Schmitt was the only professional scientist to land on the moon. Schmitt said the novel environment hardly affected his work: "It doesn't make any difference whether you're in a suit or whether you're in shirtsleeves. You're still going through the same mental process." Your mind is not in a spacesuit."
In this image, Charlie Duke collects samples from a boulder; his cuff checklist lists the tasks and timeline for the moonwalk. Duke's Apollo 16 mission returned with rocks that proved the moon's highlands had been shaped more by meteorite impacts than ancient volcanoes.