Spacewalkers Prime New ISS Solar Arrays for Deployment

STS-115 spacewalker Heidemarie Stefanyshyn-Piper is silhouetted against the Earth after swinging out the arm-like boxes of a new solar array (right) outside the International Space Station (ISS) on Sept. 12, 2006. CREDIT: NASA TV.

HOUSTON - The first new addition to the International Space Station (ISS) in more than three years is safely attached to the orbital laboratory thanks to two spacewalking astronauts and some precision robotic arm work.

Atlantis shuttle astronauts Joseph Tanner and Heidemarie Stefanyshyn-Piper outfitted the space station's new $372 million truss segments and solar arrays with vital power and data cables during the first of three spacewalks of NASA's STS-115 mission.

"Let's get this show going," Tanner said to kick off the six-hour, 26-minute spacewalk.

The successful spacewalk marks the end of a long wait for the station's new Port 3/Port 4 (P3/P4) trusses, which were delivered to NASA's Kennedy Space Center spaceport in 2000. Slated to launch in early 2003, the segments and their new solar arrays were delayed following the Columbia accident that year, station managers said.

"It's kind of like seeing your kids grow up," Kirk Shireman, NASA's deputy space station manager, said of the 45.3-foot (13-meter) integrated P3/P4 segment Monday. "We've been babying it and protecting it and improving it."

NASA plans 14 more shuttle missions to complete construction of the ISS by 2010, when the shuttles will be retired.

Always ahead of schedule, Tanner and Stefanyshyn-Piper appeared to breeze through their orbital construction tasks, ultimately completing their work early enough to get a head start on other truss chores slated for their STS-115 crewmates Daniel Burbank and Steven MacLean on Wednesday.

Only an errant spring, bolt and washer, which escaped from Tanner as he removed a launch lock from truss equipment, appeared to mar the spacewalk.

"It was breezing across the surface of structure," said Tanner of bolt and spring to mission controllers, who will track the lost items to make sure they don't pose a threat to station hardware. "I suspect this might happen again...those springs are pretty nippy."

Swift spacewalkers

Tuesday's ISS construction work began even before Tanner and Stefanyshyn-Piper stepped outside the station's Quest airlock at 5:17 a.m. EDT (0917 GMT).

The two spacewalkers waited patiently inside the airlock as MacLean and ISS Expedition 13 flight engineer Jeffrey Williams maneuvered the 35,000-pound (15,875-kilogram) P3/P4 truss segments to a berth at the end of the station's Port 1 (P1) truss.

The connections between the two trusses were never tested together on Earth, but three of four motorized bolts flawlessly mated the space station pieces in place, clearing Tanner and Stefanyshyn-Piper to begin their spacewalk. A fourth bolt was also driven in as planned.

"Look at that sunrise coming, Heide," said Tanner, who made his sixth spacewalk during today's work.

"Oh wow," replied Stefanyshyn-Piper, who made her spacewalk debut today. "That's pretty."

Tanner connected a series of power and data cables to support the P3/P4 electronics, and then joined Stefanyshyn-Piper to unlock and position the boxes and cylindrical canisters containing the folded up solar arrays and their pop-up masts.

The solar arrays are scheduled to be unfurled on Thursday.

Tanner and Stefanyshyn-Piper also removed restraints and primed motors to drive the Solar Alpha Rotary Joint (SARJ), a wheel-like joint that will rotate the massive P4 truss - and future segments - 360 degrees so their solar arrays can track the Sun.

"I'd just like to thank everyone for my first EVA," Stefanyshyn-Piper said of today's spacewalk. "It was great."

ISS spacecraft communicator and NASA astronaut Pam Melroy told the spacewalkers that they "did a phenomenal job and set the bar amazingly high for the rest of assembly."

More to come

Shireman told SPACE.com that he and his team won't rest easy until after the solar arrays are unfurled to their full 240-foot (73-meter) wingspan on Thursday.

In 2000, when Tanner and NASA astronaut Carlos Noriega helped install the first U.S. power plant at the ISS during their STS-97 mission, the solar panels stuck together as they unfolded due to a phenomenon later dubbed "stiction." Engineers found that they could work around the glitch by deploying the solar arrays in stages using a high tension mode, which allows the panels to warm up and avoid sticking to one another.

During today's spacewalk, mission controllers radioed the STS-115 crew to say that extra inspections of their shuttle Atlantis' heat shield will not be required while they are docked at the ISS. The decision, announced late Monday here at NASA's Johnson Space Center, clears the way from Wednesday's spacewalk by Burbank and MacLean.

"That's wonderful, that means we've got a good vehicle," Tanner said, while he and Stefanyshyn-Piper worked 218 statute miles (350 kilometers) above Earth.

Mission controllers woke the STS-115 crew at 11:15 p.m. EDT Monday night (0315 Sept. 12 GMT) to the sound of Ukrainian song chosen for Stefanyshyn-Piper, whose father is from Ukraine.

"It was written by Taras Shevchenko, a Ukrainian poet, and he writes to remind everyone to learn and to read as much as you can, and to teach others and learn from others," Stefanyshyn-Piper said. "And I think being up here on the ISS, that's exactly what we're doing."

Today's spacewalk marked the 70th to support the ISS, the 42nd staged from the outpost itself, and the 23rd to originate from the U.S.-built Quest airlock.

• VIDEO: First Tasks of NASA's STS-115 Mission
• Gallery: Prepping Atlantis
• Complete Space Shuttle Mission Coverage
• NASA's STS-115: Shuttle Atlantis to Jump Start ISS Construction
• The Great Space Quiz: Space Shuttle Countdown
• Complete Coverage: ISS Expedition 13