The Space Shuttle Discovery, STS-121, is scheduled for launch from Kennedy Space Center at 12:49 p.m. Pacific time Saturday. The weather may not cooperate, so the launch may be delayed (and I imagine NASA is jittery about launch too, and will delay it if a fly lands on someone's console at Mission Control). I'm sure all the major news outlets will cover the launch, especially given controversy over to launch in the first place. If there is a delay, check NASA Shuttle page for more information.
