The US space shuttle Atlantis has lifted off for the International Space Station (ISS) to deliver a long-awaited European-built laboratory.
After days of iffy weather, Atlantis roared off the launch pad at Cape Canaveral, Florida at 2.45 pm (19.45 GMT) on Thursday under clear blue skies and climbed steeply to orbit powered by seven million pounds of thrust.
Within minutes, Atlantis shed its booster rockets and external fuel tank as it departed the Earth's atmosphere, set to rendezvous with the space station on Saturday.
The shuttle was originally set to take off Dec 6, but launch was put off numerous times because of technical problems with onboard fuel sensors.
Atlantis is carrying the European Space Agency's Columbus laboratory, built mostly by EADS-Astrium in Bremen, Germany, which was supposed to go into operation in 2004.
The original mission was delayed by the suspension of shuttle flights following the Columbia disaster in February 2003, when the craft broke up while re-entering the atmosphere, killing all seven astronauts on board.
Sceptics wanted to write off the European lab project, which would have meant a loss of the 880 million euros ($1.3 billion), but it continued and will boost the European contribution to the ISS when it is delivered by a crew that includes German and French astronauts Hans Schlegel and Leopold Eyharts.
The 11-day mission in orbit will include three space walks.
During the first walk, a giant robotic arm will lift Columbus out of the shuttle's payload bay. Schlegel and US astronaut Rex Walheim will then prepare the lab for docking.
The second space walk involves the replacement of a nitrogen tank assembly used to pressurise the ISS's outside cooling system. On a third scheduled space walk, Walheim and US astronaut Stan Love will transfer experiments to the exterior of Columbus and retrieve a gyroscope. Each space walk is to last six-and-a-half hours, NASA said.
Eyharts will stay on the ISS for two to three months as a member of its crew and will become the first person to enter the Columbus module.
As the world's only heavy-lifting spacecraft in operation, the US shuttle programme is hurrying to finish space station construction so it can retire the ageing transporters in 2010. By that time, construction is expected to have doubled the station's capacity to six astronauts.