For the second day in a row, NASA workers began fueling space shuttle Discovery on Sunday in an attempt to make only the second US spaceflight since the Columbia disaster three years ago. Electrically charged clouds forced NASA to call off Saturday's launch of Discovery, delaying by a day the first space shuttle flight in a year. The weather forecast wasn't expected to improve for the launch set for 3:26 pm Eastern Standard Time on Sunday. "We knew we were going to get in a race against the weather," said launch director Michael Leinbach, adding that he expected the same for Sunday. "You can't control the weather and we have very strict rules." Fueling began just before 5:30 am. NASA Administrator Michael Griffin approved launching the shuttle for the 12-day mission despite the concerns of two top agency managers who wanted additional foam repairs.