With heavy rain pounding the Kennedy Space Center and no let up in sight, NASA managers moved up a planned 7:30 p.m. shuttle launch review meeting to 2 p.m. and promptly ruled out any attempt to launch the shuttle Endeavour on Saturday. Instead, engineers will top off the ship's on-board supplies of liquid oxygen and liquid hydrogen and prepare for another launch attempt Monday. The team will be prepared to make three launch tries in four days before standing down again to top off the hydrogen and oxygen supplies needed to power the ship's electrical generators.

Forecasters now predict an 80 percent chance of bad weather Saturday and Sunday and a 70 percent chance of another launch delay Monday. The forecast improves slightly as the week wears on, with a 60 percent "no go" outlook Tuesday through Thursday.

Endeavour's initial launch attempt Thursday evening was called off when approaching thunderstorms moved into the Kennedy Space Center area. Despite a solid 70 percent no-go forecast, launch director Michael Leinbach decided to recycle for a 24-hour scrub-turnaround and to make a second launch try this evening.

The forecast worsened to 80 percent no go by this morning and during a mission management team meeting prior to the start of fueling, NASA managers decided to forego a launch attempt today. Two waves of storms are expected to move through the area this afternoon and evening, including possible hail.

The MMT then planned a 7:30 p.m. meeting to assess the actual weather conditions and to decide whether to meet again Saturday morning for yet another tanking meeting for a potential Saturday evening launch try.

But as heavy rain swept across the space coast, NASA managers decided to move the meeting up to 2 p.m., when they decided to stand down for the weekend. Endeavour's crew will remain at the Kennedy Space Center.

Because the next launch attempt is more than 24 hours away, NASA will not reveal exactly when Endeavour's five-minute launch window will open Monday, saying only that the shuttle will take off between 4 p.m. and 8 p.m. The exact launch time will be announced Sunday.