Glenn, 85, was the first American to orbit Earth on Feb. 20, 1962. He talked about the event before an audience at COSI Columbus' John Glenn Extreme Screen Theater, the Columbus (Ohio) Dispatch said.
From detailing the process of taking the first photographs from space, to an account of his hazardous re-entry, Glenn had the audience hooked on his every word, the newspaper said.
Glenn dismissed the possibility that the militarization of space is inevitable. He also said he was particularly jealous of fellow space explorer Neil Armstrong -- the first man to set foot on the moon.
"I always tell Neil that I'm not the type of person who has really been envious of a whole lot of people," he said, "but in Neil's case, I'll make an exception. I'll be jealous. That was just an amazing thing."