NASA Hopeful Repairs Will Permit Sunday Launch

CAPE CANAVERAL, Fla. NASA is unsure what caused the hydrogen gas leak that prevented space shuttle Discovery from flying, but nonetheless will attempt another launch Sunday. Shuttle managers are hopeful that repairs at the launch pad have solved the problem. There's "a potential risk" that the leak will recur, said Mike Moses, chairman of the mission management team. That would mean yet another delay for theinternational space station construction mission, which already is running more than a month late. "We did everything we could, which is to replace all the hardware," Moses told reporters Saturday. "Yeah, we'd like to have that root cause, because now you'd feel comfortable. But I'm still going to sleep just as good tonight knowing that our chances tomorrow are really good that we did lick this problem." NASA has until Tuesday to launch Discovery before having to wait for a Russian Soyuz rocket that is set to blast off to the space station March 26. The latest delay occurred Wednesday, just hours before liftoff, as NASA was almost finished loading Discovery's external fuel tank. Hydrogen gas began leaking where a vent line hooks up to the tank.