Thunderstorms Halt Shuttle Launch Again

The space shuttle Discovery is set to make an Independence Day launch tomorrow after thunderstorms in Florida last night caused the lift-off to be scrubbed for a second consecutive day.

Nasa launch director Mike Leinbach called off the attempt with two hours 11 minutes left when it became obvious the heavy black clouds hanging over the Kennedy Space Centre all weekend were not going to clear.

Discovery's commander Steven Lindsey, who was strapped into his seat on the flight deck, agreed with the decision. "It doesn't look good today and we think that's a great plan," he said.

Mission managers decided to give the astronauts and launchpad crews a rest day today instead of returning for a third try in three days. Nasa's weather officers expect conditions to be slightly better for a 2.38pm (7.38pm BST) launch on America's national holiday tomorrow, but warn that there is still a 60% chance of a third delay.

Discovery's crew of seven, including Piers Sellers, 51, who was born in Crowborough, East Sussex, returned to crew quarters after spending almost an hour seated in the cockpit.

Engineers will now have to drain 2.3m litres of liquid hydrogen and oxygen from the fuel tanks before refuelling tomorrow for the 13-day mission.

Also being taken off the shuttle were hundreds of live fruit flies that were to be flown into space for genetic experiments at the International Space Station. They will have to be replaced with a fresh batch at a different stage of their life cycle.

"They've missed their chance of a lifetime to fly in space," said Professor Laurence Von Kalm of the University of Central Florida.