Discovery Launch Delayed Until Thursday Afternoon at the Earliest

An electrical issue affecting a main engine computer controller has prompted NASA mission managers to postpone the launch of the Space Shuttle Discovery's final mission to Thursday at 3:29 p.m. EDT, further delaying a launch that has been pushed back twice already.

Via Twitter, NASA says the chance of favorable launch conditions Thursday are only 20 percent, so it could be Friday or later before Discovery actually gets off the ground.