The space shuttle Discovery was moved back from the launch pad Thursday to the Vehicle Assembly Building at the Kennedy Space Center in Florida for the installation of a new and safer fuel tank, NASA said. (Xinhua/AFP Photo)

    WASHINGTON, May 26 (Xinhuanet) -- The space shuttle Discovery was moved back from the launch pad Thursday to the Vehicle Assembly Building at the Kennedy Space Center in Florida for the installation of a new and safer fuel tank, NASA said.

    The 6.75-km journey took more than nine hours due to a halt caused by an overheated bearing in the vehicle carrying it.

    The rollback of Discovery was originally planned for Tuesday. It was delayed to allow workers to find out any possible landing gear cracks. NASA said technicians had found no problems.

    In the assembly building, Discovery will be attached to a new and safer external fuel tank as early as June 7. A new heater willalso be added to the new tank to prevent ice buildup.

    The space shuttle was already put on the launch pad when inspectors reported ice formed on the external tank filled with super-cold fuel. Any ice breaking off the tank during liftoff could prove as lethal as in the case of Columbia, NASA warned.

    The external fuel tank has undergone many design changes since Columbia disintegrated on reentry and killed all seven astronauts aboard in February 2003.

    Discovery is scheduled to be moved again to launch pad in mid-June. The launch window for NASA's first shuttle flight since the Columbia disaster is from July 13 to July 31. Enditem