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The space shuttle Discovery blasted off yesterday for a construction mission at the International Space Station, raising hope that Nasa will be able to add laboratories for European and Japanese partners later this year.
The shuttle bolted from its seaside launch pad on time, defying forecasts of poor
weather and a potential delay from an ice buildup on its fuel tank.
It quickly disappeared from view behind low-lying clouds before reaching orbit 8.5 minutes later.
"This is a great start to a challenging mission," Bill Gerstenmaier, Nasa's associate administrator for space operations, said after the launch.
The seven-member crew, led by retired Air Force colonel Pamela Melroy, 46, plans to spend 10 days at the station.
Its main task is to prepare the station for the arrival of Europe's Columbus laboratory in early December.
Five spacewalks are planned during Discovery's visit.
During the spacewalks, astronauts will move and reattach a pair of the station's solar wing panels and install a vestibule so Columbus and Japan's Kibo module can be attached, among other tasks. While the work is similar to previous station assembly missions, Nasa has never attempted to put so much into a single flight.
"It's the combination of all these things that make this flight complicated," Gerstenmaier said.
Nasa has already accomplished one of the most challenging aspects of the mission - getting into space.
A 10cm chunk of ice that formed on the outside of the shuttle's fuel tank triggered a round of debate among engineers, who rushed to determine whether it could break off and damage the shuttle's heat shield during liftoff.
Engineers believed most of the ice would shake off in the six seconds after the shuttle's engines start, but before its twin booster rockets ignite to lift the ship off the launch pad.
Their predictions proved correct, although Nasa will not be able to determine definitively the condition of Discovery's heat shield until after a series of on-orbit inspections.
"It looked like a pretty clean ascent," astronaut Terry Virts, from the Mission Control Centre in Houston, told Melroy.
"Great news," she replied.
Video of the shuttle's liftoff showed about six pieces of the tank's foam insulation flying off the tank.
However, the foam broke away after the critical period when atmospheric forces can slam debris into the vehicle.
Nasa lost the space shuttle Columbia and seven astronauts during a landing attempt in 2003, due to undetected heat shield damage inflicted by debris during its launch.
Discovery is due to arrive at the station on Friday.
Its return to Florida is scheduled for November 6.
- Reuters