The Mobile Launcher Platform sits on the crawlerway near the Space Shuttle Atlantis at the Kennedy Space Center in Cape Canaveral, Florida

A drop in storm intensity has caused the U.S. space agency NASA to return the shuttle Atlantis back to the launch pad after it was being pulled toward its hangar for shelter. The reversal means the planned mission to resume International Space Station construction can meet a September launch deadline.

NASA's original decision Tuesday to remove Atlantis from the launch pad was the result of a weather forecast that predicted Tropical Storm Ernesto's winds would almost reach the limit for an exposed shuttle to withstand. "It does not make any sense to fool with Mother Nature," said shuttle program director Wayne Hale.

"You want to do what is safe. When the forecast persisted in bringing the storm to the Kennedy Space Center area, we decided that it would be most prudent to go back to the barn and wait it out there," he said.

But five hours later, when Atlantis had gotten half way back to its hangar, the storm's winds subsided a little, so NASA rolled it back in the other direction. "That was the data that allowed us to feel comfortable to take the vehicle back out to the pad," said shuttle launch director Mike Leinbach. "Atlantis is back out at the pad and we'll get on with pad processing after the storm passes us," he said.

Leinbach says Atlantis could be on its way with cargo to resume expansion of the International Space Station by September 6 or 7. This would be a relief for NASA, which had set September 7 as the deadline for the mission.

The date is dictated by the need to avoid a later launch that would conflict with a Russian Soyuz liftoff September 14 of a new Russian-American space station crew. It is also dependent on NASA's desire for a daylight takeoff so it can observe how much debris flies off the shuttle's external fuel tank. It wants to make sure that its tank modifications have ended the threat of a large piece of hard insulating foam falling off and threatening the shuttle's fragile heat shield, like the piece that punctured and doomed the shuttle Columbia in 2003.

NASA is eager to finish the half-built space station in the four years left before the shuttle fleet is retired in 2010. Construction stopped after the Columbia disaster forced a moratorium on shuttle flights. The only two flights since then have been tests of safety improvements to the fuel tank, but carried no major parts for the research outpost.

Now, Atlantis is packed with a 17-ton girder holding a second set solar arrays that will power future station laboratories, living quarters, and other equipment.