Another chapter in space history could be written today as Space Shuttle Atlantis prepares for what will be the final flight in the 30-year shuttle programme.
But heavy clouds and storm threats over Florida leave experts saying there is only a 30% chance of the lift-off going ahead on time.
That would be a blow to tourists who have been flocking to beaches along the coast from where there is a good view of the Kennedy Space Centre at Cape Canaveral.
Atlantis is due to launch at 5.36 this afternoon, CET for a 12-day tour to the International Space Station.
In May, Endeavour embarked on the penultimate shuttle flight.
Axing the shuttle will save NASA almost 3 billion euros a year – but many Americans will have a tear in their eye as an era draws to a close.