CAPE CANAVERAL, Florida (Reuters) - NASA prepared to launch the space shuttle Atlantis on Thursday on a long-delayed mission to deliver a $1.9 billion (968 million pound) European laboratory to the International Space Station, but weather threatened another postponement.
Atlantis was scheduled to lift off at 2:45 p.m. (7:45 p.m.British time) from the Kennedy Space Centre in Florida on thefirst space shuttle mission of the year.
But the U.S. space agency's weather experts offered only a30 percent chance of a launch as a cold front that spawnedkiller tornadoes in the southeastern United States headedtoward central Florida.
The front was expected to have lost much of its strength bythe time it reaches the Cape Canaveral area, but meteorologistssaid it could bring rain, clouds and perhaps thunderstorms.
Atlantis' mission was twice delayed in December bytechnical problems with an emergency engine cutoff system.
The shuttle will carry Columbus, Europe's first permanentspace lab, into orbit, where astronauts will attach it to thespace station during Atlantis' weeklong visit.
The European Space Agency has been waiting for the deliveryof Columbus since 2002. It was first postponed by Russiandelays launching the space station's service module, then bythe 2003 destruction of space shuttle Columbia, which groundedthe shuttle fleet for 2 1/2 years.
Twenty-three feet (7 metres) long and nearly 15 feet (4.5metres) in diameter, Columbus has room enough for three crewmembers to work on experiments. It will be launched with abiolab for cell and tissue studies and an experiment to studythe effects of weightlessness on the human body.
ESA is counting on Columbus' successful deployment and theMarch 8 launch of a cargo ship to proceed with future spaceprograms, including participation in NASA's plan to returnhumans to the surface of the moon.
Atlantis will also carry European astronaut Leopold Eyhartsto the space station, where he will oversee the setup andactivation of Columbus.
Eyharts, 50, spent three weeks aboard Russia's now-defunctMir space station nearly a decade ago. He will replace NASAastronaut Dan Tani as a member of the space station'sthree-person resident crew.
NASA plans to quickly follow Columbus' launch with thefirst flight for Japan's Kibo complex.
The agency has 13 remaining missions on the shuttle'sroster before the fleet is retired in 2010.
In addition to 12 space station construction and resupplyflights, NASA plans a mission in August or September to servicethe Hubble Space Telescope.
(Reporting by Jim Loney, editing by Todd Eastham)
