Alan Bartlett Shepard Jr. (November 18, 1923 – July 21, 1998) was an American astronaut, naval aviator, test pilot, and businessman. In 1961, he became the second man and the first American to travel into space, and in 1971, he walked on the Moon. Shepard was Chief of the Astronaut Office from November 1963 to July 1969 (the approximate period of his grounding), and from June 1971 until his retirement from the United States Navy and NASA on August 1, 1974. He was promoted to rear admiral on August 25, 1971, the first astronaut to reach that rank.