HOUSTON, United States (AFP) -- Shuttle Discovery docked with the International Space Station with a crew of seven astronauts for the most complex ISS construction mission to date.

"Welcome aboard," said the commander of the International Space Station (ISS), U.S. astronaut Mike Lopez-Alegria, shortly after the shuttle linked up with the orbiting laboratory at 2212 GMT.

The delicate maneuver took place about 220 miles (350 kilometers) above southeast Asia, NASA said, after the Discovery shot into orbit in a rare night launch late Saturday.

When the Discovery was about two kilometers (1.2 miles) from the ISS easing slowly into position, the crew of the space station turned on all its lights in a sign of welcome. About an hour and a half after the rendezvous, astronauts opened hatches and the crews of the two vehicles greeted each other and shook hands.

During the eight days Discovery remains docked to the ISS, two teams of two astronauts each will perform three spacewalks for what the National Aeronautics and Space Administration says will be the trickiest tasks ever carried out in space.

On Tuesday, Stockholm physicist Christer Fuglesang -- the first Swede in space -- and mission specialist Robert Curbeam attached a two-ton aluminum truss segment expanding the ISS.

During the two other spacewalks, astronauts will rewire the U.S.-made portion of the ISS during which power to half of the space station will have to be switched off.

The work will also include activating solar arrays, installed during a September shuttle mission, that will double the current electrical output of the ISS.

Less than three hours after docking, the crew's work schedule was interrupted to conduct an inspection the Discovery's left wing after a sensor indicated an object may have struck the vehicle at "low-intensity," NASA said.

Two astronauts were using a robotic arm to examine the wing leading edge, but so far there was no cause for concern, NASA said.

The inspection came after a sensor "detected an impact (...) of low intensity, last night at 4:30 (1030 GMT) on the left wing of Discovery," NASA television commentator Kyle Herring said.

Before Discovery linked up with the orbiting laboratory, shuttle Commander Mark Polansky maneuvered the shuttle into a backflip under the ISS to allow the station crew to film its underbelly.

The images will be examined to detect any potential damage to Discovery's heat shield in what has become a routine part of shuttle flights since the 2002 Columbia tragedy.

Discovery's astronauts used the shuttle's robotic arm Sunday on their way to the station to scan the orbiter's nose cap and wing leading edges for potential damage from Saturday night's launch from Cape Canaveral, Florida.

NASA said a preliminary look at Sunday's images showed no damage.