The 95-year-old ex-astronaut and U.S. senator was the last living member of the original Mercury Seven crew of test pilots turned astronauts.
On Feb. 20, 1962, Glenn became the third American in space, following colleagues Alan Shepard and Gus Grissom who went to space on separate but brief missions in 1961.
Glenn’s trip into low-earth orbit inside the Friendship 7 space capsule, though, would make him the first American to actually orbit our planet for an extended period of time.

John Glenn: "This is Friendship Seven. I’ll try to describe what I’m in here. I am in a big mass of some very small particles that are brilliantly lit up like they’re luminescent. I never saw anything like it. They round a little; they’re coming by the capsule, and they look like little stars. A whole shower of them coming by.
They swirl around the capsule and go in front of the window and they’re all brilliantly lighted. They probably average maybe 7 or 8 feet apart, but I can see them all down below me, also."
CAPCOM: "Roger, Friendship Seven. Can you hear any impact with the capsule? Over."
John Glenn: "Negative, negative. They’re very slow; they’re not going away from me more than maybe 3 or 4 miles per hour. They’re going at the same speed I am approximately. They’re only very slightly under my speed. Over. They do, they do have a different motion, though, from me because they swirl around the capsule and then depart back the way I am looking."
It took Glenn nearly five hours to circle the globe three times, splashing down safely into the Atlantic Ocean near Bermuda.