The Space Shuttle Program Mission Management Team decided to delay by at least one day the launch of shuttle Discovery to begin its 11-day mission to the International Space Station.
The Rotating Service Structure will not be retracted tonight.
NASA Television will air a news conference at 6:30 p.m. EDT with Mike Moses, prelaunch MMT chair and Mike Leinbach, shuttle launch director.
The delay enables engineers more time to evaluate data gathered after irregular electrical readings were received while powering up the shuttle main engines Tuesday morning.