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.

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 will attach a two-tonne aluminum truss segment expanding the ISS.

During the two other spacewalks, astronauts will rewire the US-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.

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.

Columbia's heat shield was pierced by foam insulation that peeled off its fuel tank during liftoff, causing the shuttle to disintegrate during its return to Earth in February 2003.

NASA said it will decide Tuesday morning whether Discovery's heat shield is in working order or further inspections are required.

While shuttle missions in July 2005 and July 2006 focused on improving safety following the Columbia accident, the September 2006 Atlantis mission marked the resumption of ISS construction.

Discovery blasted off late Saturday from Cape Canaveral in the first night launch in four years.

In the wake of the Columbia tragedy, night launches had been suspended to ensure adequate lighting to detect any launch debris that might endanger the shuttle.

NASA's confidence has been boosted by two nearly flawless missions this year, as the US space agency races to finish the ISS by 2010, when the shuttle fleet, down to three orbiters, is to be retired.

The Discovery mission, which ends with a December 21 landing, is part of 14 shuttle flights NASA has planned over the next four years.

NASA considers the orbiting laboratory a key part of its space exploration ambitions, which include returning astronauts to the moon and eventually setting foot on Mars.

The Discovery crew comprises two women and five men.

Except for Fuglesang, all the astronauts are American, including US Navy commander Sunita Williams, 41, whose father is from India and who will stay behind in the space station after Discovery leaves.

Polansky, the 50-year-old mission commander, served as a pilot on a 2001 shuttle flight.

His co-pilot is William Oefelein, 41, who is making his first journey into space.

The rest of the crew includes mission specialists Curbeam, Joan Higginbotham and Nicholas Patrick.

Related Links
NASA Discovery
Space Shuttle News at Space-Travel.Com