NASA may be forced to delay a December launch of the space shuttle Discovery until the new year due to a computer problem.

The American space agency fears that if the shuttle is in orbit when the year rolls over to 2007, it could cause a problem.

Instead of changing the year to after Dec. 31, the shuttle's computers would see Jan. 1, 2007, as a 366th day in 2006, throwing them out of synchronization with ground-based computers at the U.S. National Aeronautics and Space Administration.

The shuttle is slated to launch Dec. 7 on a mission to continue building the international space station, but any delay after Dec. 17 or 18 would mean the 12-day flight would be held until the calendar changes.

The space shuttle fleet is to be retired from service in 2010.