Nasa still hopes to launch space shuttle Discovery on Wednesday, despite the storms buffeting Florida as Hurricane Dennis hits the mainland US. At a countdown status briefing, space agency officials re-stated their determination to fly Discovery on the first day of its July launch window. There is said to be a 30% chance of bad weather stopping the launch on 13 July. It will be the first shuttle launch since the Columbia disaster in 2003, which killed seven astronauts. "Discovery is in excellent shape as we continue our preparations in anticipation of Wednesday's launch," Jeff Spaulding, Nasa test director told reporters here at the Kennedy Space Center (KSC) in Florida. The US space agency (Nasa) officially set the launch countdown clock ticking on Sunday at 1800 EDT (2300 BST; 2200 GMT) for a scheduled launch at 1551 EDT (2051 BST; 1951 GMT) on Wednesday. "Our main threat will be thunderstorms," said Kathy Winters, the shuttle weather officer. "With that we will have a 30% chance of KSC weather prohibiting launch."