This story was updated at 2:30 p.m. EST.
Spacewalking astronauts primed the International Space Station?s (ISS) newest room for orbital flight Tuesday as they prepare to host a visiting NASA shuttle next month.
Expedition 16 commander Peggy Whitson and flight engineer Dan Tani spent more than seven hours wiring up about half of the power, heater and cooling lines needed to prepare the station?s new Harmony connecting node for the planned Dec. 6 launch of a European-built lab. They will connect the other half during another spacewalk on Saturday.
?Another nice day at the office, here,? said Tani as the spacewalk began at 5:10 a.m. EST (1010 GMT).
Clad in their bulky NASA spacesuits, the spacewalkers spent most of their time installing a 300-pound (136-kilogram) fluid tray carries vital ammonia coolant from the space station?s main truss to Harmony. Whitson and Tani handed the 18.5-foot (5.6-meter) cable tray off like an orbital baton, then secured it in place and attached six stubborn ammonia lines to complete its installation.
?Those were hard,? Whitson said after wrestling with the final coolant line.
Whitson did spot several crystals of toxic, frozen ammonia that apparently leaked out while she worked to vent some of the coolant during her work.
?I?ve got ammonia coming out of the vent tool,? Whitson said. ?Two crystals, quite small ones. I have had some of them bounce off of me.?
Mission Control told Whitson to press ahead with her work, confident in established decontamination protocols that included brushing her spacesuit clean and baking it in sunlight before reentering the ISS.
?You?re looking strong there,? Tani told Whitson. ?She?s king of the world!?
?Queen,? Whitson, the station?s first female commander, replied with a laugh.
Tuesday?s seven-hour, 16-minute spacewalk marked the second of three planned excursions in a three-week period for the Expedition 16 crew to ready their orbital laboratory for the planned Dec. 6 launch of the shuttle Atlantis and its STS-122 astronaut crew. The shuttle mission will deliver Columbus, a European Space Agency laboratory designed to dock at one of several available ports on the hub-like Harmony node.
Busy day in space, on Earth
While the Expedition 16 crew worked outside the ISS today, Atlantis?s STS-122 crew staged a launch dress rehearsal inside their shuttle at Pad 39A of NASA?s Kennedy Space Center in Cape Canaveral, Fla.
?Atlantis is a beautiful ship and the folks here have done a wonderful job preparing it,? STS-122 pilot Alan Poindexter told reporters Monday.
But Atlantis, or any other shuttle, won?t be able to dock at the ISS until Harmony is fully equipped and outfitted, work that will continue during Saturday?s planned spacewalk.
?So there?s a bit of pressure there,? Tani told reporters Monday. ?But we like pressure and we look forward to getting outside and getting the work done.?
Shuttle astronauts delivered Harmony to the ISS just last month, leaving the ISS crew with a packed November of orbital construction to complete the node?s installation and activation. The astronauts moved the nearly 16-ton Harmony node to the front of the station?s U.S. Destiny lab last week.
?We?ve still got a lot of challenges up in front of us,? said Derek Hassmann, NASA?s lead Expedition 16 flight director, after the spacewalk. ?But based on all the successes we?ve had up to this point, I expect the rest of the stage to go very well.?
Whitson, Tani and fellow crewmate Yuri Malenchenko - who watched over today?s spacewalk from inside the ISS - have already pledged to work through their traditional Thanksgiving holiday this Thursday in order to meet their tight schedule. Hassmann said if all continues to go well, the crew should have a relatively light work day on Thursday.
?They are just a hard-charging, get it done crew,? said Kenny Todd, NASA?s ISS program integration and operations manager, of the Expedition 16 astronauts on Nov. 16. ?We?ll have to make sure they understand that it?s Thanksgiving and that they take some time and take a breath.?
In addition to their main spacewalking tasks today, Whitson and Tani also managed to squeeze in extra work to hook up additional power and data lines, as well as part of a power transfer system that allows the ISS to feed power to visiting shuttles. Mission managers are now scrambling to choose additional chores to add to this Saturday?s excursion, said NASA?s lead Expedition 16 spacewalk officer Tomas Gonzalez-Torres.
Tuesday?s spacewalk was the 98th excursion dedicated to ISS assembly or maintenance. It was also Whitson?s third spacewalk, giving her a total of 18 hours and 36 minutes of spacewalking time. Tani also raised his tally to three spacewalks, ending with a total time 18 hours and 1 minute. Both spaceflyers will also participate in Saturday?s spacewalk.
Tani sent an orbital greeting to his wife Jane, who watched her astronaut husband at work from inside NASA?s Mission Control in Houston.
?I?ll put my A-game on here,? said Tani. ?Hi Jane! Hi sweetie!?
NASA will broadcast the Expedition 16 crew's third spacewalk outside the ISS live on NASA TV on Nov. 24 beginning at 4:30 a.m. EST (0930 GMT). Click here for SPACE.com's ISS mission updates and NASA TV feed.
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