), is an American former Navy SEAL, aerospace, ocean, and mechanical engineer, and NASA astronaut, who served as commander of Expedition 1,[1] the first crew on the International Space Station.

[3] He graduated from Arcadia High School in Phoenix, Arizona in 1967, and received a Bachelor of Science degree in Aerospace Engineering from the United States Naval Academy in Annapolis, Maryland in 1971.

[4] He completed Basic Underwater Demolition/SEAL (BUD/S) training in 1972, then joined the United States Naval Special Warfare Command and qualified as a Navy SEAL.

After Shepherd was selected for NASA Astronaut Group 10 in 1984,[6] rumors spread that he had answered a standard interview question about what he did best by saying, "kill people with knives"[7] but he later refused to confirm or deny the account, commenting "it's too good a story".

[9] In 1986, Shepherd's Navy SEAL training proved unexpectedly useful to NASA as he helped to direct the underwater salvage operations of the Space Shuttle Challenger after its destruction.

[11][16] STS-52: Columbia (October 22 to November 1, 1992) was the 10-day mission deployed the Laser Geodynamic Satellite (LAGEOS), and conducted U.S. microgravity payload experiments.