In preparing for their mission, in addition to the usual Apollo spacecraft training, Young and Duke, along with backup commander Fred Haise, underwent an extensive geological training program that included several field trips to introduce them to concepts and techniques they would use in analyzing features and collecting samples on the lunar surface. During these trips, they visited and provided scientific descriptions of geologic features they were likely to encounter. In July 1971, they visited Sudbury, Ontario, Canada for geology training exercises, the first time U.S. astronauts did so. Geologists chose the area because of a wide crater created about 1.8 billion years ago by a large meteorite. The Sudbury Basin shows evidence of shatter cone geology familiarizing the Apollo crew with geologic evidence of a meteorite impact. During the training exercises the astronauts did not wear space suits, but carried radio equipment to converse with each other and scientist-astronaut Anthony W. England, practicing procedures they would use on the lunar surface.