CAPE CANAVERAL, Fla. (AP) - NASA has found cracks in space shuttle Discovery's fuel tank.

Discovery is grounded until at least the end of the month by a hydrogen gas leak. The leak forced NASA to call off last Friday's launch attempt.

Later, a 20-inch crack in the foam insulation of the fuel tank was discovered.

On Wednesday, workers removed sections of the damaged foam for analysis. They were surprised to find two cracks in the actual aluminum surface of the tank.

NASA spokesman Allard Beutel says tank cracks like this have been fixed before at the production facility in New Orleans. But the work has never been attempted at the launch pad. Beutel says engineers are looking at what it would take to fix the tank at the pad.