An American astronaut has lost his place on the next space shuttle mission after falling off his bicycle.
Tim Kopra was injured in the accident last weekend.
His place as the lead space walker on the Discovery's flight next month will be taken by another astronaut, Steve Bowen, a shuttle veteran.
The mission has been postponed half a dozen times because of technical problems. It is now scheduled for launching on 24 February.
The shuttles are being retired this year after being in use for 30 years.
Russia already has taken over the job of flying crew members to the station, a $US100 billion project by 16 nations.