Spacewalkers tackle toughest Hubble repair job yet
CAPE CANAVERAL -- Facing their toughest job yet, spacewalking astronauts floated outdoors Saturday to give the Hubble Space Telescope a better view of the cosmos by installing a new high-tech science instrument and fixing a broken camera.
It was the third spacewalk in as many days for the shuttle Atlantis crew, expected to be the most challenging ever performed because of the unprecedented camera repairs. Astronauts have never tried to take apart a science instrument at the 19-year-old observatory.
John Grunsfeld and Andrew Feustel got started on the daunting job Saturday morning as the joined shuttle and telescope soared 350 miles above the planet. Orbiting so high put Atlantis and its astronauts at an increased risk of being hit by space junk. NASA had another shuttle on launch standby in case a rescue was needed.
"Hello, Hubble," Feustel said as the telescope doors swung open.
Before tackling repairs to the burned-out camera, the spacewalkers had to install the $88 million Cosmic Origins Spectrograph, which is designed to detect faint light from faraway quasars and provide greater insight into how planets, stars and galaxies formed.
To make room for the supersensitive instrument, Grunsfeld and Feustel removed the corrective lenses that restored Hubble's vision in 1993. The space telescope had been launched three years earlier with a flawed mirror that left it nearsighted. But the newer science instruments had corrective lenses built in, making the added contacts unnecessary.
"This is really pretty historic," Grunsfeld said as he and Feustel lifted out the huge contact container.
The switch — taking out the 7-foot-long box containing the corrective lenses and putting in the cosmic spectrograph — was expected to be straightforward. It's exactly the kind of replacement work astronauts performed on four previous repair missions.
For the camera repairs, though, Grunsfeld and Feustel were going to have to open up the seven-year-old instrument and pull out fried electronic parts.
