Live Launch Countdown Coverage

The Space Shuttle Discovery's countdown clock is still ticking after being activated again Saturday in anticipation of today's launch at 10:39 a.m. Discovery was set to launch its "Return to Flight" mission July 13, but Launch Director Mike Leinbach scrubbed the launch because of a problem with the liquid hydrogen engine cutoff sensor system. This time they say everything looks good and it's a go even if the cutoff sensor malfunctions again. Mission Control has activated its Live Virtual Launch Control Center . The Center allows you to follow the last minute preparations online. See the Return to Flight Web coverage for further information on the launch.