What did john glen serve?

John Glenn served as a U.S. Marine Corps fighter pilot, a NASA astronaut, and a United States Senator from Ohio. He became the first American to orbit the Earth in 1962 during the Mercury-Atlas 6 mission, known as Friendship 7. After retiring from NASA, he was elected to the Senate, where he served from 1974 to 1999. Glenn's contributions to space exploration and public service have made him a significant figure in American history.