CAPE CANAVERAL, Fla. – A week before Endeavour's planned liftoff, NASA was analyzing a cabin leak in the space shuttle Tuesday.
The leak was detected over the weekend. NASA thought it fixed the problem by tightening a loose bolt, but testing Monday night confirmed air was still escaping from the crew cabin, said NASA spokeswoman Tracy Young.
Engineers have yet to pinpoint the leak, which could require so much work that NASA might not be able to launch Endeavour on Aug. 7.
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NASA's planned launch of the Mars lander Phoenix later this week could also interfere with Endeavour's flight.
The Phoenix has only three weeks in which to launch before facing a two-year wait, and the mission already was pushed back from a Friday launch to Saturday because storms delayed rocket preparations.
Space agency officials have indicated they want the Mars craft on its way before Endeavour gets a turn at launching.
The shuttle's trip to the international space station includes schoolteacher-turned-astronaut Barbara Morgan, who was Christa McAuliffe's backup in 1986.
McAuliffe was killed along with six others when the Challenger broke up shortly after liftoff.