John Glenn entering the Mercury “Friendship 7” Spacecraft during pre-launch preparations on February 20, 1962.  He was the third American in space and the first American to orbit the Earth, circling it three times in 1962. Glenn resigned from NASA in January 1964. Glenn was first elected to the United States Senate in 1974 and served until January 1999. In 1998, at age 77, Glenn flew on the Space Shuttle Discovery's STS-95 mission, making him the oldest person to enter Earth orbit, and the only person to fly in both the Mercury and the Space Shuttle programs.  He died at the age of 95 on December 8, 2016.  Prior to his illustrious career with NASA and with the U.S. Senate, John Glenn was a U.S. Marine who, while serving in Korea, flew 63 missions with the Marine Fighter Squadron 311. As an exchange pilot with the Air Force, Glenn flew 27 missions in the F-86 Sabre. In the last nine days of fighting in Korea, Glenn shot down three MiGs in combat along the Yalu River.