The Associated Press
SPACE CENTER, Houston - Two space shuttle astronauts floated outside yesterday to finish installing the international space station's giant, newly extended solar wings.
NASA officials breathed a collective sigh of relief late Monday after feverishly working to create a plan that successfully unfurled the second wing.
During their afternoon spacewalk, the second of three planned for this mission, Endeavour astronauts Joe Tanner and Carlos Noriega planned to make electrical connections so that power from the new solar wings can be distributed to the rest of the station.
The spacewalkers, who installed the panels Sunday, also were to relocate a communications antenna to the top of the truss that holds the solar wings' batteries and electronics. While atop the truss, they were instructed to use their helmet cameras to provide engineers with close-up views of loose tension cables on the right solar wing.
The remaining spacewalk tasks will pave the way for the arrival of the American-made Destiny lab module in January.
The unfurling of the second wing was delayed until Monday after the first wing appeared too slack when it was released a day earlier to its entire length of 115 feet in just 13 minutes.
It snapped back and forth as it went out, and two tension cables apparently came off their pulleys, leaving the blanket of solar cells less taut than desired.
NASA officials came up with a start-and-stop unfurling procedure to prevent the same thing from happening to the second wing.
"I know I aged a lot the last 24 hours and I can't afford to age much more," lead flight director Bill Reeves joked after the second wing was successfully spread Monday evening. Both wings are now producing electricity for the space station.
Shuttle commander Brent Jett Jr., using computer commands, carefully unfolded the second wing a few feet at a time in the start-and-stop procedure that took almost two hours. A couple sections stuck together and had to be jarred loose by retracting the panel a little and then shooting it back out.
"There was a fair amount of tension in the cockpit," Tanner said after the second wing was unfurled.
"Needless to say, the room down here was filled with electricity," Mission Control replied.
Reeves said officials are still determining the best way to fix the first solar wing's tension problem, which might include having Tanner and Noriega do repairs during their third spacewalk Thursday. That's when they are set to finish wiring the solar wings and installing other equipment on Alpha.
The main concern is whether the first wing would be secure enough during the docking or undocking of a space shuttle, or during orbit-changing maneuvers. The worry is that vibrations could tear, bend or break off the solar panels.
The future of space station construction hinges on the astronauts' ability to install the solar panels, which will provide much needed power to the newly inhabited outpost.
The $600 million set of solar wings is the largest, most powerful and most expensive ever built for a spacecraft.
They measure 240 feet from tip to tip, including connecting beams, and are 38 feet across. That's longer than the wingspan of a Boeing 777 jetliner.
Alpha commander Bill Shepherd and his two Russian crewmates have been on board since Nov. 2.
The two crews are unable to meet until Friday. The hatches between the two craft remained sealed because of the difference in cabin air pressure.