Thunderstorms prevented Discovery from blasting off on its final journey on Thursday.
Rain was pounding the area, and meteorologists said there was little opportunity for breaks in the weather. Just before daybreak, mission managers called off the afternoon liftoff and said they would try again Friday.
So far, the weather outlook is better for Friday; however, the passage of a cold front could lead to some gusty winds. If officials decide to go ahead with the launch, liftoff would be at 3:30 p.m.
Thursday's delay was the latest in a series of postponements for NASA's oldest and most travelled space shuttle. Liftoff was delayed earlier this week because of gas leaks and an electrical problem.
NASA has until Sunday to launch Discovery, otherwise the shuttle will remain grounded until the beginning of December because ofunacceptable solar angles.
This will be the final flight for Discovery and NASA's next to last shuttle flight. Endeavour is scheduled to lift off at the end of February.