Astronauts Norman Thaygard, William Readdy and Roberta Bandar head for the launch pad at Cape Canaveral. The shuttle Discovery thundered into orbit at 9:52 a.m. EST Wednesday on a research mission with seven astronauts and a slimy assortment of flies, worms, frog eggs and mold. The launch was delayed about an hour by weather concerns and a cranky fuel cell.