James Benson Irwin, USAF (March 17, 1930 – August 8, 1991) was an American astronaut, aeronautical engineer, test pilot, and a United States Air Force pilot. He served as Apollo Lunar Module pilot for Apollo 15, the fourth human lunar landing. He was the eighth person to walk on the Moon and the first and youngest of those astronauts to die. Irwin was one of the 19 astronauts selected by NASA in April 1966. He was chosen as commander, with John S. Bull as Lunar Module Pilot, for LTA-8, an environmental qualification test of the Apollo Lunar Module in a vacuum chamber at the Houston Space Environment Simulation Laboratory. He then served as a member of the astronaut support crew for Apollo 10, the first mission to carry the full Apollo stack to the Moon and the dry run for the first crewed Moon landing. Following that assignment, Irwin served as backup Lunar Module Pilot for the second Moon landing mission, Apollo 12.
An astronaut (or cosmonaut) is a person trained by a human spaceflight program to command, pilot, or serve as a crew member of a spacecraft.
Although generally reserved for professional space travelers, the terms are sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and tourists.