Astronauts Ice Up Hubble Camera

Shuttle Columbia’s astronauts completed five days of repairs to the Hubble Space Telescope on Friday, installing a high-tech, super-cold refrigerator in hopes of reviving a comatose camera.

It was the fifth and final spacewalk of the mission, described by NASA as the most challenging service call ever made to the 12-year-old telescope.

Spacewalkers John Grunsfeld and Richard Linnehan connected the 310-pound refrigerator to an infrared camera that has not worked for the last three years. They also hung a large radiator on the outside of the telescope and hooked up cables and plumbing that are part of the $21-million cooling system.

The system passed its initial tests, but astronomers will not know for at least a month whether the repairs will allow the camera to peer back into the dark, dusty regions of the universe and resume its study of young star clusters, exploding stars and planetary atmospheres.

The astronauts set a spacewalking record for a single shuttle mission: 35 hours and 55 minutes. It surpassed, by 29 minutes, the 1993 record held by the first Hubble repair team. Both flights featured five spacewalks.

During the mission, a central power unit was installed, along with stronger solar wings, a new pointing mechanism and a powerful new camera.

“Many people on this mission, privately, didn’t think that we would be able to accomplish everything that we had set out in our plan,” said Hubble program manager Preston Burch.

All that remained, for the astronauts, was the release of Hubble early today from the shuttle’s cargo bay.

The infrared camera was installed on Hubble in 1997. But it stopped working in 1999 after its supply of nitrogen ice ran out. The ice was needed to keep the infrared detectors at their operating temperature of 350 degrees below zero.

To fix the problem, NASA pioneered a system that uses neon gas as the coolant and a refrigeratorlike compressor. The compressor consists of three tiny turbines that spin at 400,000 revolutions per minute, 50 to 100 times the operating speed of a car engine. It is virtually vibration-free, crucial for Hubble’s precise picture-taking.

Columbia’s astronauts will return to Earth on Tuesday, bringing back all of the telescope equipment that was removed.

“We’ve given Hubble a new power system that will take it off into the next decade of discovery. We’ve given it new eyes to see deeper into the universe than it’s ever been able to see before,” said Grunsfeld, an astrophysicist who led Columbia’s spacewalking team.

Astronomers everywhere, he said, “will be able to enjoy the beauty and inspiration that these new pictures from Hubble will bring.”

A satellite that will join others in relaying those pictures rocketed into orbit Friday evening. NASA’s newest Tracking and Data Relay Satellite also will provide communication links for space shuttles, the international space station and other science spacecraft circling Earth.