Posted: Thu, Jul 5, 2007, 1:47 PM ET (1747 GMT)

NASA has delayed the launch of the Dawn asteroid mission by 24 hours after weather interfered with pre-launch preparations. The launch, which had been scheduled for Saturday afternoon, has been rescheduled for Sunday between 4:04 and 4:33 pm EDT (2004 and 2033 GMT). A lightning advisory at the launch site Thursday morning prevented workers from fueling the second stage of the Delta 2 rocket that will launch Dawn, forcing the delay. Current weather forecasts call for a 60-percent chance of unacceptable conditions at the time of Sunday's launch attempt. The launch of Dawn, a mission that will visit the main belt asteroids Ceres and Vesta, had previously been delayed a week because of a problem with a crane at the launch pad used to assemble the Delta 2.