Discovery rolled back to hangar

NASA has rolled back Space Shuttle Discovery to the hangar on Thursday to have a new, safer external fuel tank installed. The new tank will have a heater element to prevent the buildup from ice.

The space shuttle was rolled away on a huge caterpillar-track platform, along a specially built road almost as wide as an eight-lane highway.

The rollback started at less than 1mph and was expected to take six to seven hours. But after 1 1/2 hours the bearing of a vehicle carrying the space shuttle overheated. The trip then resumed at a slower pace after workers let the bearing cool down and packed it with grease.