It was on this day on February 20, 1962 that John Glenn became the first American to orbit the Earth. He ended up doing that 3 times over the course of his time at NASA. Glenn was the oldest of 7 astronauts chosen for Project Mercury. John Glenn had a storied military career before space exploration. He joined the US Marine Corps in 1943 and flew 59 missions in the South Pacific during World War 2. He upped that to 90 missions during the Korean war and in the last 9 days of that war, shot down a total of 3 MIG's. He went on to become a US Senator from the state of Ohio and was re-elected 3 times after.