Astronauts successfully stitched together tears in a sheet of solar panels on the International Space Station early yesterday morning in a seven-hour operation that was one of the most difficult ever attempted in space.
Spacewalker Scott E. Parazynski snipped a guide wire that had snagged on the long, wing-like solar array and another wire that had gotten tangled in the damaged area.
He also laced five makeshift braces made of aluminum, wire and insulating tape - dubbed "cuff links" by the crew - into the panels to stabilize them.
The Frankenstein-style stitching kept the solar panels together as flight controllers at Johnson Space Center in Houston slowly unfurled the array to its full length.
Astronaut Doug Wheelock floated about 90 feet away from Parazynski at the base of the solar array and monitored the operations.
There were concerns that Parazynski could have been electrocuted as he worked on the solar panels, which continued to operate during the repairs, and in the tense buildup to the spacewalk, NASA repeatedly warned that station construction would have to be halted if the wing could not be fixed.
But one of the spacewalkers commented that there was nothing more problematic during the repair than some smudges on his glove.
A later inspection inside the station turned up a small tear on one of the spacewalkers' gloves, and a pair of needle-nose pliers was lost in space.
Mission controllers are tracking the pliers and said they don't believe the tool poses any collision risk for the station.
Overall, mission managers were pleased with how smoothly the operation went.
"I'm happy to report the crew performed flawlessly today," said lead spacewalk officer Dina Contella during a news conference at mission control in Houston.
Parazynski and Wheelock, who arrived at the space station Oct. 25 on the shuttle Discovery, began their spacewalk at 6:03 a.m. EDT.
Parazynski was suspended by his feet over the solar array at the end of two robotic arms, controlled by astronauts in the space station.
As he approached the solar array, which is more than 100 feet from the space station, Parazynski described the snarl of wires around the panels as a "hairball."
No other astronaut had ever been so far away from the safe confines of the cabin.
Parazynski spent about 2 1/2 hours repairing the solar panels. He and Wheelock returned to the space station at 1:22 p.m.
Mission managers are still trying to figure out how the solar sheet tore in two places, but they think a guide wire snagged on the sheet at it unfolded on Tuesday.
The station had enough power from its other solar arrays to keep its crew and the Discovery astronauts comfortable. But NASA needed to get all the power-generating systems working to accommodate new Japanese and European laboratories scheduled to be delivered during the next few months.
By yesterday afternoon, the array was providing 217 amps of electricity, which was 3 amps less than what they would normally get from an array, said Mike Suffredini, NASA's space station manager.
NASA still has to figure out what to do about a rotary joint that isn't working right and can be used only sparingly to turn another set of solar power wings toward the sun. Steel shavings were found inside the joint during a spacewalk last Tuesday, apparently the result of grinding parts.
Samples of those shavings will return to Earth aboard Discovery and help pinpoint the source of the trouble. There may not be enough time for another repair during this mission.
The shuttle is scheduled to return to Earth on Wednesday.
Jia-Rui Chong writes for the Los Angeles Times. The Associated Press contributed to this article.