CAPE CANAVERAL, Florida, the United States, July 14 (Xinhuanet) --NASA officials said Thursday that it's likely to take several days of trouble-shooting before the space agency could make another attempt to launch space shuttle Discovery.

    Deputy shuttle program manager Wayne Hale told a news conference here that a Sunday launch is still a possibility, but it is a "really optimistic good-luck scenario."

    NASA engineers are racing against the clock on Thursday to try to figure out the cause for a faulty fuel sensor which forced them to postpone the launch of the space shuttle Discovery on Wednesday.

    The Discovery's seven astronauts had already been strapped into their seats on Wednesday when NASA called off the mission with just 2 hours and 20 minutes to go before scheduled liftoff.

    The decision to scrub was made after one of the four fuel sensors in the shuttle's external tank failed during a countdown test after the tank had been filled with liquid hydrogen. Enditem