The countdown began Sunday afternoon after managers declared the shuttle ready to blast off Wednesday. Gas leaks had forced back-to-back launch delays, but NASA test director Steve Payne said that repairs took care of the problem.
“She’s been an incredible vehicle, and she caps a long and distinguished career with this particular flight,” Payne told reporters. “She’s always amazed us with everything that she can do. We expect this flight should be no different.”
Launch time is scheduled for 3:52 p.m. Wednesday. Weather forecasts indicate a 70 percent chance of good conditions for take-off.
Only one other shuttle launch remains on NASA’s official schedule, ending 30 years off shuttle flight.