Astronauts Work Through Repair Trouble at Hubble

In this photo provided Thursday, May 14, 2009, by NASA shows astronaut Andrew Feustel, mission...

In this photo provided Thursday, May 14, 2009, by NASA shows astronaut Andrew Feustel, mission specialist, performing work on the Hubble Space Telescope as the first of five STS-125 spacewalks kicks off a week's work on the orbiting observatory. The shuttle is perched on the end of the Canadian-built remote manipulator system. Feustel, teamed with astronaut John Grunsfeld, not pictured, will join the veteran spacewalker on two of the remaining four sessions of extravehicular activity later in the mission. (AP Photo/NASA)

(AP)

Spacewalking astronauts had to put a refurbished pair of gyroscopes into the Hubble Space Telescope after a brand new set refused to go in Friday, but scientists were satisfied nonetheless and confident the observatory would point precisely to ever more distant objects in the cosmos.

Replacing the gyroscopes was the top priority of the repair mission, and the struggle had NASA on edge for two hours.

Thanks to the spacewalkers' effort, Hubble ended up with four brand new gyroscopes and two refurbished ones that were original 19-year-old telescope parts, said to be almost as good as the new ones. The telescope also got fresh batteries.

Later, Mission Control told the cheering astronauts the gyroscopes and new batteries all worked properly.

It was the second spacewalk in as many days for the Atlantis astronauts, who once again were bedeviled by problems. On Thursday, another two-man team installed a powerful new camera and a computer data unit after struggling with a stubborn bolt. NASA had hoped for an easier, less stressful spacewalk, but instead had to endure more drama.

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As on Thursday, the astronauts got their work done, but it was harder and took longer than expected. Friday's spacewalk was one of the longest ever, lasting nearly 8 hours, and Mission Control told the weary crew members that they could sleep in and start Saturday's spacewalk a little late.

Hubble chief scientist David Leckrone said he had a pet theory on "why things have been a little turbulent for the crew for two days in a row."

"After seven years of not having people around, Hubble has lost its accommodation to people," Leckrone said at a late Friday news conference. "It's gone wild again. So we have to tame it. That will happen I'm sure."

The first two spacewalks have gone "a long way" to extending Hubble's life, Leckrone said. And Hubble's new main camera installed on Thursday passed its functional test.

Leckrone said Saturday's spacewalk, which is one of the most challenging involving never-before done in-space repairs of a science instrument, will probably go smoothly because that was his big worry. And nothing has gone quite as expected, he said.