Thunderstorms threatened to delay the final space shuttle launch, set the date, and lightning near the pad caused a brief flurry of concern to NASA engineers first concluded that the shuttle was OK.
Lightning struck a water tower about 500 meters from the launch pad at noon on Thursday, said the space agency. Technicians checked for signs of electrical problems, but a review board has ruled out any injury.
Weather today, in turn, looked grim, with only a 30% chance of acceptable time to start on time, 11:26
NASA test director Jeff Spaulding said the spacecraft had successfully started with the worst prognosis.
"There are some opportunities there," said Thursday that the rain settles "This day is very difficult if you make a decision not to go and that is a good time."
NASA closed its 30 years of the Space Shuttle Program to target the asteroids and Mars, the preferred destinations of the White House. Private companies take its place to pull the cargo and crew to the International Space Station.
NASA has until Sunday, maybe Monday, to get Atlantis and its four astronauts in orbit. Otherwise, the probe will remain grounded until next week due to a rocket launch Air Force, which is a priority.
Rain or shine, hundreds of thousands of people expected to jam the area to launch. Some estimates put the crowd at about 1 million. Dozens of astronauts are already in the city, including the first shuttle pilot Robert Crippen, who opened the era aboard Columbia in 1981.
"It is a sad moment for me, of course, but it is also the time when I feel proud," Crippen told the Associated Press.
Atlantis is on track with the space station for a year applies. NASA wants to orbit the Outpost is a well-stocked case of slow loading bays trading began.
The first privately-term supply - by the technologies of space exploration - is tentatively scheduled for late this year.
12-day trip during the Atlantis is due to expire again on touchdown at Kennedy Space Center July 20, 42 anniversary of the first steps on the Moon.
"There's an old saying that it is better to travel well than to arrive," said Spaulding. "And I must say, after 30 years, our program and the shuttle in all their missions, at less worked fine. ... And after landing, I think we can say at this stage as we arrived. "