Astronauts aboard the International Space Station and U.S. Space Shuttle Discovery are spacewalking to install a new set of solar wings to help power the station.

The U.S. space agency NASA says two astronauts will spacewalk for at least 6.5 hours Thursday as they install a support framework (truss) for the solar wings.

NASA says the two astronauts spent the night in the Quest airlock at reduced air pressure to prepare their bodies for the task.

The crew members are using the space station's robotic arm to help maneuver the final piece of the truss into place.  The structure is nearly 14 meters long and weighs about 14 metric tons.

It will support the solar wings due to be unfurled Friday, forming the final segment of the station's solar electricity grid and bringing the 10-year-old orbiting outpost up to full power.

Friday, besides their work duties, the Discovery astronauts will take part in a special interactive Webcast with Voice of America.  Viewers can be a part of this exchange by sending their questions to  

The spacewalk Thursday is the first of three scheduled to take place since Discovery docked at the space station earlier this week.  The shuttle also is dropping off a new water-recycling system designed to convert urine into water.

Discovery brought the space station's newest crew member to begin his four-month assignment in space.  Koichi Wakata is the first Japanese citizen to live aboard the station.  He is to replace American astronaut Sandra Magnus, who is scheduled to return to Earth on the shuttle.