WASHINGTON, Nov. 20 (Xinhua) -- Two astronauts aboard the International Space Station conducted a more-than-seven-hour spacewalk, outfitting the outpost's new Harmony node in its new position.

Expedition 16 commander Peggy Whitson and flight engineer Daniel Tani began the excursion outside the orbital lab at 5:10 a.m. EST (1010 GMT), according to NASA TV.

They first routed the power and cooling system lines between the ISS and its new Harmony node, which they moved to the front of station's U.S. Destiny module last week.

Then the duo installed a 300-pound fluid line tray to the side of the Harmony node. The tray is 18.5-foot long and was handed off several times between the two spacewalkers to maneuver it into its final position. It is one of two loops to be installed outside Harmony during two spacewalks this week.

Later in their spacewalk, they connected heater avionics lines to Harmony. With their primary goals complete, the two spacewalkers reentered the Quest airlock, officially concluding the spacwalk at 12:26 p.m. (1726 GMT).

This is the second spacewalk of the Expedition 16 crew. On Nov.9, Whitson and flight engineer Yuri Malenchenko completed the first spacewalk, preparing for the move of Harmony. And this Saturday, the station astronauts will conduct the third spacewalk to complete outfitting the Harmony.