CAPE CANAVERAL, Fla. Its official: Space Shuttle Atlantis will blast off September 8 on a mission to outfit the International Space Station, kicking off a series of outpost construction missions and setting the stage for the arrival of its first full-time crew in November.

And get this: The agency plans to send Atlantis and its U.S.-Russian crew aloft during a remarkably short two-and-a half-minute launch window that will open at 8:45 a.m. Eastern Daylight Time (12:45 GMT) that day.

"I dont think weve ever had a shuttle launch window this narrow," Kennedy Space Center (KSC) spokesman Bruce Buckingham after NASA managers made the launch date and the launch window official during an all-day meeting Tuesday at KSC.

"Weve never done that before," added KSC spokesman Joel Wells.

NASA on past missions to the international station has launched shuttles during five-minute windows that were timed to put ships on course for dockings at the new outpost. Narrowing the window will enable NASA to save fuel and increase flight safety for its astronaut crews.

The Atlantis launch window, for example, will open precisely when the shuttles launch pad is aligned perfectly with the orbit of the international station.

The shuttle crew, consequently, will not waste any rocket fuel steering the ship up to the station. And that, in turn, means more fuel reserves will be left to deal with any engine performance shortfalls that might crop up during an eight-and-a-half-minute climb into orbit.

A July 1999 flight of Columbia is a good case in point. On that mission, a hydrogen-fuel leak left the shuttle in an orbit 7 miles (11.3 kilometers) lower than intended.

A situation like that on an upcoming station-construction mission could leave a shuttle without enough fuel to make it to the outpost.

The shorter launch window also could be a lifesaver: It will improve the chances that a shuttle would have enough gas to make it to an emergency landing site on the east coast of the United States in the event that two of its three main engines failed in flight.

Nine such sites are located between Myrtle Beach, South Carolina and Gander, Newfoundland, and would be available if engine problems prevented a crew from making an unprecedented landing attempt back at KSC or emergency sites in Spain and North Africa.

The shorter launch windows will be the norm during a flurry of backlogged station-construction missions that had been on hold until the recent arrival of the outposts new Russian-made living quarters.

All tolled, NASA plans to launch the Atlantis flight and eight other complicated station-construction missions by the end of 2001 a pace unprecedented in recent agency history.

"This mission begins a series of station-assembly flights aboard the shuttle during the next year that will be as complex as anything NASA has ever done, including landing a man on the moon," said shuttle program manager Ron Dittemore.

"I believe these flights will be as impressive as they are complex," he added, "and were excited and ready to get started."