NASA canceled the launch of the space shuttle Columbia Wednesday after the freshly repaired spaceship sprang a leak similar to one that grounded the entire fleet for three months. The National Aeronautics and Space Administration said the launch, originally set for early Thursday, would be postponed indefinitely.
NASA had been optimistic about the mission - which would have been the first since Discovery took the flawed Hubble Space Telescope aloft in April - right up until the leak erupted during fueling Wednesday evening, forcing Columbia's third launch postponement since May.
Safety concerns after fuel leaks were discovered in Columbia in May and in Atlantis in June prompted NASA to ground the fleet.
The space agency has maintained that the shuttles do not share a design flaw, but an official said Discovery - being prepared for an Oct. 5 liftoff with the European Ulysses solar probe - may be checked for similar leakage.
``If we ... magically found the problem [on Columbia] and corrected it, we'd be talking on the order of three or four days, but even I don't think that's realistic,'' NASA shuttle program director Robert Crippen told a news conference here.
NASA must launch Columbia by Sept. 14 to avoid infringing on the three weeks set aside to ready Discovery for its flight. If Discovery does not fly by Oct. 23, its Ulysses mission must wait 13 months for a particular planetary alignment to reoccur.
Scientists who were working on Columbia's star-gazing mission were ``disappointed - and that's the understatement of the year,'' said Edward Weiler, NASA's chief astrophysicist.
``We really felt we were going to go today,'' he said.