John Glenn (July 18, 1921 – December 8, 2016) was a United States Marine Corps aviator, astronaut, and politician. Before joining NASA, Glenn was a distinguished fighter pilot in World War II, the Chinese Civil War and the Korean War. In 1957, he made the first supersonic transcontinental flight across the United States. He was one of the Mercury Seven, military test pilots selected in 1959 by NASA as the nation's first astronauts. On February 20, 1962, Glenn flew the Friendship 7 mission, becoming the first American to orbit the Earth, and the fifth person and third American in space. After retiring from NASA, he served from 1974 to 1999 as a Democratic U.S. senator from Ohio. In 1998, Glenn flew on the Space Shuttle Discovery mission STS-95, making him the oldest person to enter Earth orbit and the only person to fly in both Project Mercury and the Space Shuttle program. He received the Presidential Medal of Freedom in 2012. (Full article...)