Discovery astronaut replaced after bike crash

An astronaut who crashed his bicycle last weekend won't be taking part in space shuttle Discovery's final voyage next month.

Astronaut Timothy Kopra suffered unspecified injuries in the accident Saturday, just 1½ months before Discovery's planned liftoff. He is recuperating and on indefinite sick leave.

In a rare swap-out Wednesday, NASA removed Kopra from the crew and added veteran spaceman Stephen Bowen, who flew last May on the most recent shuttle flight. Bowen will take over Kopra's spacewalking duties during the 11-day flight. Kopra had been designated as the lead spacewalker and was to venture out twice to perform work on the International Space Station.

The shuttle flight has been on hold since November because of fuel tank cracks. Just last week, NASA said it had finally zeroed in on a cause for the potentially dangerous cracking. Shuttle repair work is continuing; Discovery's target launch date is Feb. 24.

This is the second time this month that NASA had had to deal with crew issues.

Last week, NASA named a backup commander for the final flight of Endeavour in April. The official commander, Mark Kelly, remains at the hospital bedside of his wife, Rep. Gabrielle Giffords, who was seriously wounded in a shooting in Tucson, Arizona. His identical twin brother, Scott, is flying on the space station right now as its skipper.

To cut down on preflight injuries, NASA has a whole list of prohibited activities for astronauts assigned to space missions. Among the banned high-risk sports: motorcycle riding, skiing, parachuting and acrobatic flying. Bicycling is not on the list.

NASA has refused to elaborate on Kopra's injuries, citing medical privacy. The accident involved only Kopra's bicycle, officials said, and occurred near his Houston-area home.

Kopra, 47, a retired army colonel, spent two months on the space station in 2009.