John H. Glenn Jr.: Aviator and Astronaut In John Glenn's long aviation career, he flew with the U.S. Marines and the U.S. Air Force, set a speed record, and shot down enemy aircraft. But he is best known as the first American to orbit the Earth and, later in life, as the oldest person to fly in space. In World War II, Glenn volunteered for naval aviation training and became a Marine pilot. He flew 59 combat missions in F4U Corsair fighters and received the Distinguished Flying Cross (DFC) and two Air Medals. In the Korean War, he was one of a handful of Marines selected to fly USAF F-86 Sabre jets in a pilot exchange program. Glenn shot down three North Korean MiG-15 fighters and soon became known as the "MiG Mad Marine." He flew 27 of his 90 Korean War missions in USAF jets, earning another DFC and eight Air Medals. Following the war, Glenn set a speed record flying a Chance Vought F8U Crusader coast-to-coast across the United States in 3 hours, 23 minutes in July 1957. (A USAF B-58A Hustler bomber, crewed by Capts. Robert G. Sowers, Robert MacDonald and John T. Walton, set a new record in March 1962 by crossing the country in 2 hours, 58 seconds. This record-setting B-58 is on display in the museum's Cold War Gallery.) Glenn became world famous on Feb. 20, 1962, when he orbited the Earth three times in his Mercury spacecraft Friendship 7. He was the first American astronaut in orbit, and the USAF's Atlas rocket made his historic flight possible. At that time, Atlas was the only booster powerful enough to put the Mercury spacecraft into orbit. Click here to return to the Missile Gallery. Find Out More Related Fact Sheets Convair B-58A Hustler Note: The appearance of hyperlinks does not constitute endorsement by the National Museum of the USAF, the U.S. Air Force, or the Department of Defense, of the external website, or the information, products or services contained therein.