Can't make it to the Moon? Try California's volcanoes!

By California Volcano Observatory April 7, 2026

If you listened to astronauts describing the surface of the Moon during the NASA Artemis II flyby yesterday, you might be interested to learn about the roles California's volcanoes - and the USGS - have played in the history of lunar exploration!

California is where the history of USGS research into the Moon's geology really began. The first Astrogeologic Studies Unit (later Astrogeology) to be set up in the USGS was created in Menlo Park, California (the former home of the California Volcano Observatory). Starting in 1960, Gene Shoemaker led a small, NASA-funded group of geologists focused on lunar research in Menlo Park, including lunar geologic mapping, Apollo landing site selection, and providing expert training for astronauts before and during the Apollo Era. The group was later upgraded to a full research Branch of Astrogeology in 1961 and moved its headquarters to Flagstaff, Arizona in 1963.

However, USGS scientists in California - and California's volcanic landscapes - remained a key part of preparation for lunar landings. In fact, you can hardly throw a rock in California without hitting a lunar training site! Because of their resemblance to landscapes that scientists had observed on the Moon, Medicine Lake Volcano, the Coso Volcanic Field, Amboy Crater area in the Mojave Desert, Ubehebe Craters in Death Valley, and the Mono Craters area near Long Valley were all used for astronaut training and lunar rover testing.

Two white men wearing jeans, button-down shirts, and bulky harnesses with huge rectangular backpacks sit on the frame of a stripped-down white motorized buggy-like vehicle. Their harnesses have two old-fashioned video cameras pointing forward. On the front of the vehicle, a large metallic mesh radio antenna dish is raised on a pole. In the background, mounds of dark, jagged, black lava rock sit in front of a skyline composed of several rounded red hills of volcanic scoria.

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Apollo 16 astronauts John Young (right) and Charlie Duke (left) ride in Earth-adapted Lunar Roving Vehicle "Grover" in the Coso Volcanic Field near Ridgecrest California, November 1971. Photo by NASA.

A group of five white men wearing cowboy hats, jeans or khakis, and button-down shirts are standing on a sandy gray surface ringed by large gray boulders of volcanic rock. In the background, a number of bare, rubbly, rocky peaks are lit by afternoon sun. The men are examining hand samples of rocks and one is smoking a pipe.

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University of Texas professor William R. Muelhberger (left foreground) with Apollo 16 commander John W. Young (right foreground), astronaut Charles Duke (center), geologist David Wones (second left), and astronaut Anthony England on an Apollo 16 geology field trip to Mono Craters in June 1971. Photo by NASA.

A red-haired man wearing khaki pants, brown boots, a green jacket, and a black cowboy hat stands on a steep, reddish slope surrounded by manzanita bushes and small pine trees. He is taking notes in a small notebook. In the background, a thick pine forest is lit by sunlight.

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View of Donald A. Beattie (manager of NASA's lunar surface experiments) during a geological field trip to the Medicine Lake Volcano, California in September 1965. Beattie was joined by astronauts William Anders (Apollo 8), Alan Bean (Apollo 12), and Rusty Schweikert (Apollo 9). Photo by NASA.

Here, we feature visits to the Coso Volcanic Field (first photo), Mono Craters (second photo), and Medicine Lake Volcano (third photo) with astronauts from multiple Apollo missions. In each spot, astronauts learned to map and sample volcanic rocks similar to what would be found on the Moon. They had to learn not only to identify and interpret what they were seeing, but also think of ways to define the geology of spots that they couldn't reach (for example, using rocks at the base inaccessible mountains to decide what rocks could be found on top). This was also a chance to practice communicating geologic observations to scientists who weren't physically present as practice for talking with NASA from the Moon - exactly what just happened on yesterday's flyby!