NASA has finally set a date for the shuttle Discovery's liftoff. It is now scheduled for Wednesday March 11 at 9:20 PM EDT. The countdown clock begins at the T-43 hour mark at 7 PM on Sunday, according to NASA. Shuttle mission STS-119 will be headed for the International Space Station. The launch was originally scheduled for February 12, but a problem with a flow control value had to be fixed. The issue was detected when the shuttle Endeavour returned from its November 2008 mission.