Live in orbit: Audacious assembly under way

The third of five planned spacewalks during Discovery's stay at the International Space Station is under way.

Mission specialists Scott Parazynski and Douglas Wheelock switched their spacesuits on battery power at 4:45 a.m. EDT, marking the official start time for the excursion and the final stages of the mother of all station assembly tasks. "Another great day at the office, Wheels," Parazynski said.

Wheelock was the first outside the hatch to the U.S. Quest airlock. Station skipper Peggy Whitson was watching on from the window at the front of the compartment.














Crane operators Stephanie Wilson and Dan Tani are prepared to mount the 17.5-ton P6 solar array girder to the far left end of the station's central truss, a job considered the toughest astronauts will face in assembly of the 15-nation station construction project.














Click here to take a look at what's involved: Audacious assembly

You can watch the action unfold here in The Flame Trench. Simply click the link below the top image above to launch our NASA TV viewer and round-the-clock coverage of NASA's 120th shuttle mission.