Top: (L) The heaviest rock brought back from the moon, Big Muley. (R) Muehlberger (pointing) training astronauts in the Marathon Basin of West Texas. Bottom : Muehlberger (right) and John Powers (center) examine Big Muley at the lunar receiving laboratory in Houston.
Top: (L) Buzz Aldrin (left) and Neil Armstrong examine rock samples in west Texas near Sierra Blanca. Armstrong is shown clearly holding an Estwing Rock Hammer. (R) Muelhberger (left) talks with astronaut John W. Young, Apollo 16 commander, during an Apollo 16 geology field trip to Mono Crater, Calif. Astronaut Charles Duke, lunar module pilot, is seen at frame center, talking to geologist David Wones (second left). Astronaut Anthony England, Apollo 16 spacecraft communicator is at right. Photo credit: NASA Bottom: Apollo 15 astronauts Jim Irwin (right) and Dave Scott examine the interior of the Rio Grande Gorge from the west rim during a field traverse.
Left: Patricia Dickerson co-led numerous training field trips for space shuttle astronauts. Right: Mark helper simulates lunar field work on Earth at Haughton crater in the Canadian Arctic in 2010.