Apollo astronauts train at the Nevada Test Site

In February 1965, before legendary astronaut Neil Armstrong became the first person to set foot on the moon, Armstrong, along with fellow astronauts Dick Gordon, Buzz Aldrin, Dave Scott, and Rusty Schweikart, paid a visit to the pockmarked desert of the Nevada Test Site, as part of their lunar training.

The three-day training mission, which began on February 16, 1965, was the first of three separate visits by NASA astronauts to the test site that year. The purpose of the unusual field trip was to help the astronauts develop a familiarity with geological formations similar to those they might encounter on the moon's surface. In particular, the field training exercises were designed to help them identify craters of meteoritic and volcanic origin.

On the first day of the tour, the astronauts visited Yucca Flat, where the Lawrence Radiation Laboratory, Livermore—as the Lab was known back then—and the Los Alamos Scientific Laboratory had been conducting nuclear explosive tests since the 1950s. There, they examined a number of craters produced by nuclear and chemical high explosives blasts, with particular interest focused on the Sedan Crater.

The Sedan Event, the largest of the Project Plowshare experiments, was conducted on July 6, 1962 by Lawrence Livermore. This 100-kiloton blast produced a crater approximately 1,200 feet in diameter with a depth of 320 feet into the desert floor. For the 1965 NASA training exercise, the famed Sedan crater served as the main stand-in for the meteoric impact craters that the astronauts might expect to find on the moon. At Sedan, the astronauts conducted geological and geophysical observations, under the guidance of Eugene Shoemaker of the U.S. Geological Survey.

The next day, the group flew, via Air Force helicopters, across a wide area of desolate desert country near the western edge of the test site. While there, they observed, for purposes of comparison, the geology of ancient volcanic formations made by the Timber Mountain Caldera, the largest caldera known in the United States, whose features are similar to those of the moon's surface.

On the third day of the visit, the group visited the Nuclear Rocket Development Station, where testing on nuclear reactors for space-rocket engines was being conducted. A project to supply nuclear propulsion for space travel, known as Rover, had begun in 1955 as a joint Livermore/Los Alamos project. Los Alamos continued the program for many years after Livermore had shifted its attention in 1957 to a flying reactor effort, known as Project Pluto.

Back at the test site, the astronauts' visit went barely noticed by the regular residents of the site, as publicity for the exercise was kept to a minimum. While waiting in line at the Area 12 cafeteria for lunch, the astronauts were assumed to be just another working group in the forward area. The crew reported that the substantial dinner later that night in the "Steak House" (Camp Mercury Cafeteria) was welcome, after a hard day's work in the field.

Training at the test site was so successful that a little more than a year after Neil Armstrong landed on the moon, on July 20, 1969, astronauts were back at the test site for further training missions. In November 1970, astronauts for Apollo 14 trained at the Schooner crater (another Livermore Plowshare project) and visited the Sedan Crater. The Apollo 16 crew trained at Schooner in October 1971, and Apollo 17 astronauts conducted exercises at Schooner and Buckboard Mesa in August 1972.