A Delta II rocket launching twin satellites to the moon will make a second launch attempt Friday after weather scrubbed this morning's try.
All systems were "go" for the United Launch Alliance rocket and NASA spacecraft, and clouds and showers crept too close to Cape Canaveral's Launch Complex 17B.
But high-altitude winds that could have pushed the rocket off course proved too strong to allow a launch at either 8:37 a.m. or 9:16 a.m.
On Friday, NASA's $496-million Gravity Recovery and Interior Laboratory mission, or GRAIL, has two instantaneous launch opportunities at 8:33 a.m. and 9:12 a.m.
The forecast is the same as today's: There's a 40 percent chance of conditions favorable for launch, with thick clouds and showers possible.