NASA Starts Space Shuttle Endeavour Countdown Aug. 4

NASA will start the launch countdown for space shuttle Endeavour's STS-118 mission at 9 p.m. EDT Saturday, Aug. 4, at T-43 hours. The countdown includes 27 hours, 3 minutes of built-in hold time leading to a preferred launch time at 7:02 p.m. EDT Tuesday, Aug. 7. The launch window extends an additional five minutes.