WASHINGTON, March 14 (Xinhuanet) -- NASA said Tuesday the launch of space shuttle Discovery would be postponed from May to at least July.

    A malfunctioning fuel tank sensor is said to cause the delay.

    The planned launch in May is expected to be the second shuttle flight since the Columbia disaster in February 2003, which was blamed on insulation foam falling off the fuel tank during liftoff.

    NASA resumed shuttle flight in July last year, but the foam problem emerged again and forced the U.S. space agency to ground the shuttle fleet one more time. Enditem