Low clouds over Kennedy Space Center have prompted NASA's mission controllers to delay the Shuttle's return to Earth by a day.

There were two landing opportunities today, but the possibility that the landing strip could be obscured means both have been ruled out. Mission controllers were hoping the cloud would clear, and sent Discovery on an extra orbit to kill some time. However, the clouds remained stubbornly in place, and the landing attempt was called off.

Tomorrow, Shuttle Commander Eileen Collins and her crew will have several opportunities to bring Discovery in, with two windows of opportunity at Kennedy Space Center in Florida, and two at the Edwards Air Force Base in California. White Sands in New Mexico is also on the backup list.

The Shuttle Discovery is the first to fly since the loss of Columbia, with all hands, in February 2003. A falling piece of foam damaged Columbia's wing during launch. This damage had weakened the plane sufficiently that it broke up on re-entry.

Collins acknowledged that the crew would be thinking about Columbia when they begin their descent, but added: "we'll be very focused on the job at hand". ®

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