Dr. Scott E. Parazynski on the spacewalk, during which electrical hazards were a concern.
Dr. Scott E. Parazynski works along the International Space Station’s truss assembly as he prepares equipment for mounting during his solar array repair mission.
Dr. Scott E. Parazynski, a former emergency room physician, mended wounds on the wing, which developed two tears while being deployed Tuesday.
If the procedure had not been successful, the array, on the left side of the station, might have had to be discarded. The loss of a solar array would have reduced the ability to produce power, possibly constraining future construction on the station.
Mission managers knew that wires had become snagged and had torn the array during deployment. But they did not know the nature of the snag. They had hoped that repairs would be a simple matter of moving a wire off a hinge.
Dr. Parazynski, riding on an extension of the station’s robotic arm to reach the damaged array, said his view of the repair site revealed a “hairball” of wire, with guide wire for the array caught in another wire running through the hinge connecting the panels.
Looking at a close-up view available from Dr. Parazynski’s helmet camera, Pamela A. Melroy, the commander of the space shuttle Discovery’s current mission, said, “Sounds like you have some surgery to do, Dr. Parazynski.”
He inserted the first “cufflink,” a wire-and-metal contraption created by the astronauts using instructions from the ground, into place along the array shortly before 9 a.m. Eastern time. That stabilized the area around the tears so he could work on the wire.
With the sun at his back and his shadow sharp against the brilliantly golden array, Dr. Parazynski began cutting wires, cautiously planning each snip in consultation with Ms. Melroy and mission controllers on the ground.
Dr. Parazynski took care to keep clear of the swaying array, occasionally dampening its motion with a prodder shaped like a hockey stick. He cut out two offending lengths of wire and moved on to insert the remaining cufflinks.
Astronauts inside the station then began the delicate process of extending the array to its full length, with Dr. Parazynski and Col. Douglas H. Wheelock, stationed at the base of the array, watching for any hint of trouble.
The cufflinks held. Cheers could be heard over the communications loop.
Concerns going into the spacewalk focused on electrical hazards and possible damage to space suits. A list of warnings read to Dr. Parazynski by Paolo A. Nespoli, the Italian astronaut who was choreographing the spacewalk from the station, included touching sharp edges of bolts, solar cells, hinges and other areas of the array.
“I’m not sure there’s much left to touch,” Dr. Parazynski replied.
Mr. Nespoli said, “We’re not even halfway through the warnings,” and went on to warn against touching areas with “pinch points” and high electrical current, which carry a risk of shock and “molten metal.”
During the procedure, Dr. Parazynski said he saw no sparks.
Dr. Parazynski, by coincidence, was one of the best astronauts for the unusual spacewalk. Now on his fifth trip to orbit, he has spent more time in spacewalks than all but four others in the history of the program. And, at 6 feet 2 inches, he is among the tallest astronauts and well-suited to work on the array from a safe distance.
“It’s a bit of a reach here,” he said at one point.
Ms. Melroy responded, “That’s what those monkey arms are for,” and then added, “Not many people in the office could do what you’re doing right now.”
To which Dr. Parazynski replied, “I hope they don’t have to.”
The only apparent slip-up came at the end of the spacewalk, which lasted more than seven hours. An errant set of needle-nose pliers floated away and could be spotted drifting below the station. Mission managers said the tool is not likely to pose a threat to the shuttle or station before falling back to Earth, but said they would track it on radar.
The successful repair makes it possible to shoot for launching the next module for the station, the European-made Columbus laboratory, early next month, said Michael T. Suffredini, the manager of the station program.
Even after the spacewalk yesterday, the station still has one major problem: a damaged rotary joint on the right-hand side.
The crew of Discovery will bring back some of the metal shavings from the joint when they return this week, as early as Wednesday. Those shavings, Mr. Suffredini said, will provide clues about which part is damaged.
A full inspection of the joint, which was scheduled to take place during this mission, is now likely to be pushed back into next year, as will any repair.
Mr. Suffredini said the station’s current power set-up, with one set of two arrays rotating and the right-side arrays parked but drawing a reasonable amount of sunlight, should give the station enough power to get through the December mission and perhaps well beyond.
The repairs made to the solar array should hold through the predicted end of United States involvement in the station program in 2015, Mr. Suffredini said. It did, however, leave the array looking as though it had acquired a dueling scar.
“The idea for this was to regain the functionality of the solar array,” Mr. Suffredini explained. “It wasn’t about looking good when it was over with.”
The array, he acknowledged, “Doesn’t quite look like we’d expected. But you know, it’s just like anybody — you have your baby, your baby is beautiful to you. Our baby is still beautiful to us.”
