Glenn will become the oldest person in space, lifting off at age 77

WASHINGTON (CNN) -- He was the first American to orbit the Earth and now, 36 years later, John Glenn is in the final months of rigorous preparation before blasting off again. Is he ready?

Glenn was a solo voyager that first time, in 1962, when he circled the planet three times, spending less than five hours in space. Now, the former astronaut turned senator is set for a 10-day trip as part of the team on space shuttle Discovery, due for launch on October 29.

By then, Glenn will be 77 -- the oldest human ever to travel in space.

CNN Correspondent John Holliman recently questioned the past and future astronaut about the upcoming mission. Critics call it a taxpayer-funded joyride, but Glenn, who pushed for the assignment, says it will prove valuable in learning more about space and the aging process.

CNN's John Holliman interview's Glenn Interview excerpts Complete interview