Sen. John Glenn is going to get a good dunking.

The Ohio Democrat headed back to basic training Saturday - astronaut training.For the next two weeks, the 76-year-old who was the first American to orbit the Earth will be studying, practicing and working in NASA simulators to prepare for his return to space this fall. Training will include water survival exercises.

"You're simulating bailing out at a low altitude," Glenn said. "You go out on a pole over the pool and drop off," he said. "It's enjoyable to be doing some of those physical things."

Glenn had to demonstrate he was extraordinarily fit before getting approval for the space shuttle flight, a nine-day mission scheduled to begin Oct. 29.

The National Aeronautics and Space Administration has been working Glenn's training around his Senate schedule, with the senator spending every sizable break at the Johnson Space Center in Houston.