Astronauts install solar unit on space station

By Jeff Franks

HOUSTON (Reuters) - Astronauts made a tricky job look easy on Tuesday when they used a robot arm to latch a 17.5 tonne solar power girder to its new home at the end of the International Space Station.

Arm operators Daniel Tani and Stephanie Wilson could not see the 35-foot-long (10-metre) girder's destination from inside the station and had to guide it in with directions from spacewalkers Scott Parazynski and Douglas Wheelock.

"Looks good, spaceman," one of the spacewalkers said as they performed the task.

"Fantastic job of guiding us in," Tani told them.

NASA had said the installation of the truss, which sat atop the station for seven years awaiting the move to its permanent location, was one of the most challenging manoeuvres ever on the $100 billion (49 billion pound) space outpost.

It also was critical because the next key task will be to unfurl the 240-foot-long (73-metre) solar panels folded up inside the unit.

The electricity they generate will be needed for an upcoming expansion of the 9-year-old station and took on added importance when NASA shut down on Sunday a malfunctioning rotary joint that is a key part of the station's power system.

The 10-foot (three-metre) joint, on the opposite side of the station from the newly installed girder, rotates to keep one of the outpost's solar panel arrays pointed at the sun to produce electricity.