Updated

Astronaut Michael Lopez-Alegria broke the U.S. record of most time walking in space Thursday as he and another astronaut did maintenance work outside the international space station during their third spacewalk in nine days.

Lopez-Alegria surpassed the previous U.S. record of just over 58 hours midway through his chores with fellow American Sunita Williams. He has a ways to go to claim the all-time record, though — Russian Anatoly Solovyov has logged more than 77 hours.

Lopez-Alegria and Williams finished a primary mission of the their spacewalk: tossing quilt-sized thermal sheets from the international space station.

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The two large thermal covers were folded up with smaller shrouds that had been covering an electronics box and were used to prevent parts of the space station from getting too hot or cold. Scientists believe they will burn up upon entering Earth's atmosphere.

"I don't think I could do it any better than that," Lopez-Alegria said to Williams as the first package floated away.

Lopez-Alegria joked that they had an easier time folding up the shrouds than their spacewalking colleagues who helped fold up a stubborn solar array during space shuttle Discoverkgloggy's mission to the space station last December.

"Solar arrays wish they could retract this well!" he said.

In the past, engineers wanted to make sure that jettisoning items would not strike the station, but they have grown more comfortable with the idea.

"We've gotten more proficient in jettison analysis and understanding the safety of jettisoning," lead spacewalk officer Glenda Laws said recently. "We expect the shrouds ... to look like a large bundle of laundry."

The spacewalk marked the first time three spacewalks have been conducted in such a short period without a space shuttle docked to it. The first two spacewalks had similar tasks, and flight controllers thought they could save preparation time by squeezing them together.

Lopez-Alegria planned to conduct a fourth spacewalk Feb. 22 with Russian flight engineer Mikhail Tyurin.

That spacewalk will be Lopez-Alegria's 10th. The previous U.S. time record for spacewalks was held by astronaut Jerry Ross, who has made nine spacewalks.

During Wednesday's spacewalk, chief astronaut Steve Lindsey chatted with the spacewalk ground team. A day earlier, he had escorted astronaut Lisa Nowak back to Houston from Florida, where she was charged with attempted murder and attempted kidnapping, accused of trying to harm a woman she viewed as a romantic rival for the attentions of astronaut William Oefelein. NASA has put her on leave for 30 days and removed her from mission activities.