WASHINGTON (AP) _ Now that he's been back on Earth for a few weeks, John Glenn can chuckle as he admits to the embarrassing details of his history-making flight: The flying part was fine but the return was a problem.

After the space shuttle Discovery ended its nine-day mission, there was a long time lapse before its crew emerged for the traditional inspection walk around the craft.

America's oldest astronaut gave a reason Tuesday: nausea. John Glenn was throwing up.

``I didn't feel so hot,'' he told Ohio reporters gathered for a yearend interview.

Glenn, who is retiring as a Democratic senator from Ohio, said he'd been concerned about space sickness, which many astronauts experience while aloft, so he took precautions during liftoff.

On the return, however, ``I preloaded with too much fluid coming down,'' he said.