In his book Collapse, Jared Diamond claims, "When NASA wanted to find some place on Earth resembling the surface of the Moon, so that our astronauts preparing for the first moon landing could practice in an environment similar to what they would encounter, NASA picked a formerly green area of Iceland that is now utterly barren." This struck me as wrong. Growing up, I heard the slag fields around Sudbury, Ontario, helped get the lunar astronauts accustomed to the moon's desolation. I've heard similar things about islands in the Canadian arctic and deserts in the American southwest. I wonder if the real explanation is that the astronauts had to take geology lessons. True? -Cameron Barr, Edmonton

You nailed it. Most astronaut field trips were about geology, not getting used to a bleak hell unfit for life. For that they could have stayed in Houston.

The astronauts trained at lots of sites around the world, at least a couple of which humans had turned into wildernesses. According to Diamond, "Since human settlement began, most of [Iceland's] original trees and vegetation have been destroyed, and about half of the original soils have eroded into the ocean. As a result . . . large areas . . . that were green at the time that Vikings landed are now lifeless brown desert." Similarly, much of the area around Sudbury, Ontario, was a moonscape in the 1960s due to nickel smelting.

In neither case, however, was environmental devastation the main draw for NASA. Instead it was geological features. One thing the moon had plenty of was rocks, and that meant geology training lest astronauts wander right past specimens they were there to study.

After a few lectures, the NASA science team realized geology field trips (GFTs) better suited the former test pilots' learn-by-doing style. Following a successful preliminary trip to Arizona in 1963, official GFTs began in ‘64.

GFT sites were chosen because of geologic similarities to spots on the moon. Usually that meant deserts-you couldn't see the rocks if they were covered with vegetation. However, the astronauts also visited densely wooded northern Minnesota to see outcrops of anorthosite. Grand Canyon trips taught stratigraphy, the study of rock layers, though nobody expected to find water-carved lunar canyons. The trainees even visited craters formed by shallow underground nuclear tests in Nevada and by conventional explosives in Alberta, since bomb craters form the same way meteorite craters do.

The astronauts visited Iceland in 1965 and 1967. Although they saw many formerly green spots, the centerpiece of the visits was the Askja caldera, site of multiple volcanic eruptions. It probably wasn't verdant even in pre-Viking days.
Ontario's Sudbury basin was a GFT destination in 1971 and ‘72 because it's a meteorite impact crater. There astronauts studied shatter cones (conical, striated rock chunks) and impact breccia (rock consisting of mineral fragments embedded in natural cement).

Another destination was Craters of the Moon National Monument in Idaho. My assistant Bibliophage, who's been there, reports, "I can only say if there's a more moonlike place on earth, I don't want to see it."

Geology wasn't the sole reason the astronauts hit the road. Some training locations were chosen for topographical similarity to landing sites (e.g., a New Mexico river gorge standing in for the moon's Hadley Rille). To prepare for emergency landings on their return, the astronauts also underwent jungle survival training in Panama and desert survival in Nevada and Washington.

Contrary to what you might imagine, these traverses were conducted without space suits-too bulky in earth gravity.