John Glenn was an astronaut for NASA.
John Herschel Glenn Jr. ( July 18 , 1921 -- December 8 , 2016 ) was a United States Marine Corps aviator , engineer , astronaut , and United States Senator from Ohio . Before joining NASA , Glenn was a distinguished fighter pilot in World War II and Korea with six Distinguished Flying Crosses and eighteen clusters on his Air Medal . The Mercury Seven were the group of seven Mercury astronauts announced by NASA on April 9 , 1959 . The United States Astronaut Hall of Fame , located just south of Titusville , Florida , honored American astronauts and featured the world 's largest collection of their personal memorabilia , focusing on those astronauts who have been inducted into the Hall ; as well as Sigma 7 , the fifth manned Mercury spacecraft .