John Glenn doesn't want people to believe he's too old to be an astronaut again. At 76, the senator from Ohio will be the oldest man in space when he boards the shuttle for a nine-day mission this October.
Glenn, continuing training for his upcoming space mission, donned rappelling gear and his orange flight suit Monday to practice exiting the space shuttle in the event of emergency.
Glenn and his five fellow crew members took turns popping out of the hatch of a life-size shuttle mockup and lowering themselves down the side of the spacecraft. The exercise simulates how the astronauts would exit the shuttle if there was an emergency while the vehicle was on the ground, either before takeoff or after landing.
The youngest of Glenn's fellow crew members was not even born when he became the first American to orbit the earth 36 years ago.
NASA has given Glenn the official and boring title of "payload specialist" for the mission, but some Americans would call Glenn a true national hero. Now, instead of the fearless fighter pilot turned space traveler, John Glenn is a grandfather who will try to show age is not an excuse to go blasting off into orbit.
Glenn seems to never have had any doubts. "None whatsoever," Glenn tells CBS News Correspondent David Fehling. "Quite the opposite. No, I'm happy as can be."
Glenn will help with scientific experiments to see how older bodies deal with zero gravity. "We're using this for science, for everybody's benefit," Glenn says.
Reported by CBS News Correspondent David Fehling