The rollout of space shuttle Discovery to the launch pad at the Kennedy Space Center, Florida, was briefly delayed Wednesday because of a hairline crack found inthe foam insulation on the ship's external fuel tank. (Photo: Xinhua/AFP)

    WASHINGTON, April 6 (Xinhuanet) -- The rollout of space shuttle Discovery to the launch pad at the Kennedy Space Center, Florida, was briefly delayed Wednesday because of a hairline crack found inthe foam insulation on the ship's external fuel tank.

    NASA determined that the crack is a minor imperfection that does not need repair after consulting experts from the tank-manufacturing facilities in New Orleans, Louisiana.

    The rollout of Discovery is one of the last major steps before NASA resumes shuttle flights that have been suspended since the Columbia tragedy in February 2003, in which all seven astronauts aboard were killed.

    A suitcase-sized foam insulation falling from the external fueltank of space shuttle Columbia on its liftoff was blamed for its midair disintegration, which has forced an extensive redesign of the shuttle's external fuel tank.

    Discovery's launch is set between May 15 and June 3, a time frame that will allow it to dock with the International Space Station, the shuttle's destination.

    The crack in Discovery's external tank caused a delay of at least two hours before NASA began the nearly 6.8-km trek of moving the shuttle from its assembly building to the launch pad, at barely 1.6 km per hour.

    Last-minute work on the shuttle's thermal protection shield has already delayed the rollout by two days.

    Delays in transferring Discovery to the launch pad could make amid-May lift off difficult to complete. Enditem