Hubble set for redeployment in space

Astronauts ace spacewalks; Hubble flies Saturday

Mission specialists Richard Linnehan, left, and John Grunsfeld celebrated the end of the week's nearly 36 hours of Hubble spacewalking with some extra-vehicular thanks to NASA and Hubble program staffers on the ground.

JOHNSON SPACE CENTER, Texas (CNN) -- Amid a shower of congratulations from the ground and on board, space shuttle Columbia astronauts on Friday concluded a final spacewalk in a series of apparently successful repairs and upgrades to the Hubble Space Telescope.

While extensive checkouts and "aliveness" tests remain to be performed, initial data at the 11:06 a.m. EST conclusion of Friday's seven-hour, 20-minute spacewalk indicated that all new elements of the four-story Hubble are operative.

The observatory -- now with some $172 million of new equipment -- is scheduled to be redeployed into orbit at 5:03 a.m. EST on Saturday, when it and shuttle Columbia will be above the island of Guadelupe in the Pacific.

The next effort on Friday followed quickly: Columbia's crew began a 36-minute series of jet firings to start raising the Hubble's orbit level by some three-and-a-half miles.

VIDEO CNN's Miles O'Brien reviews a week of repair by Hubble Space Telescope astronauts (March 8) Play video (QuickTime, Real or Windows Media)    •  Cult 3-D model of the space shuttle  •  Milestones in Space Shuttle History  •  STS-109 Mission guide   MORE STORIES  •  Hubble preview   INTERACTIVES  •  View Hubble's servicing mission  •  Cult 3-D model of the Hubble  •  Top 10 Hubble Discoveries  •  Hubble's Greatest Images

Spacewalkers Richard Linnehan and John Grunsfeld took the unusual step of posing for one of the shuttle's cameras near the end of their Friday walk, the blue-and-white Earth their backdrop as they sent thanks to NASA's shuttle and Hubble program workers for their long preparations and week of support on what's now a total of almost 36 hours of spacewalking Hubble-servicing in orbit.

A physics teacher, Linnehan joked, had once told him he'd only "take up space." A jovial thumbs-up was Linnehan's laughing signal to that teacher that he'd been right in ways he may not have foreseen.

"Awesome, like in 'totally, awesome, dude,'" is how Preston Burch -- the Hubble program manager from the Goddard Space Center -- characterized the mission in a status briefing held shortly after spacewalk concluded. For Burch and his associates, the week has meant a potentially stunning boost in the telescope's capacity and durability. The replacement of the power control unit, alone, may mean avoiding an eventual disruption in a system that already had experienced some erratic power flow.

Burch did say that a small washer floated away during the installation of the cooling system's radiator, but that he anticipates no problem from that in terms of the shuttle's return to Earth. Bryan Austin, the lead mission manager, added that the underperformance of one of Columbia's own freon cooling systems that worried engineers after launch on March 1 is presenting no known problem for the shuttle on its anticipated Tuesday re-entry into the atmosphere.

During Friday's spacewalk -- the fifth from shuttle Columbia in as many days -- a specially designed new cryogenic cooler went into the orbiting observatory along with a radiator, both instruments installed to chill a highly sophisticated camera that needs extremely cold temperatures to function (-334 degrees Fahrenheit, -203 degrees Celsius).

The camera, called the Near Infrared Camera and Multi-Object Spectrometer, or NICMOS, has been dormant since 1999 because of a small leak in the original cooling mechanism.

Technicians say it will take roughly a month for the new cooling system to get NICMOS down to its optimum working temperature. First images testing the re-cooled camera's effectiveness should be available around early May.

Deeper, clearer view of cosmos

After their spacewalk Friday, Linnehan, left, and Grunsfeld -- back aboard Columbia -- talked about how the cold temperatures of space stiffened the coolant tubing they were installing on the Hubble.

In a seven-hour spacewalk on Thursday, astronauts Jim Newman and Mike Massimino installed a new $76 million camera on Hubble.

"Guys you're doing tremendous," said Grunsfeld from inside Columbia. "First three days we gave Hubble the power -- and now you've given Hubble the eyes. Good job."

Called the Advanced Camera for Surveys, or ACS, the camera is expected to greatly improve Hubble's ability to create images of the cosmos. It was latched into place about 7 a.m. EST.

"What the crew did was put the turbocharger on this telescope," said Garth Illingworth, deputy principal investigator for ACS at the University of California at Santa Cruz. "The Advanced Camera is going to add 10 times the capability to Hubble."

It will take more than nine weeks to fully align the new camera. But it has passed its first tests.

"ACS phoned home and told us it was okay and raring to go," Illingworth said at a news conference.

The ACS is about the size of a telephone booth. It replaces the Faint Object Camera, the last of Hubble's original instruments. The ACS should become what NASA describes as the workhorse for Hubble. It will search for extra-solar planets, scour regions deep in space and observe weather on Earth.

Illingworth said the new camera will allow scientists to look back in time to "start exploring in more detail the fringes of the dark ages in the universe."

More power, new wings

In this photo, the Hubble's new smaller solar wings are visible. They were installed in Monday and Tuesday's spacewalks.

On Wednesday, Grunsfeld and Linnehan successfully performed the mission's most sensitive and warily anticipated feat, changing out the 12-year-old telescope's power control unit, or PCU. The protocol required powering down and restarting Hubble for the first time since it was deployed from space shuttle Discovery on April 25, 1990.

On Tuesday, Newman and Massimino added a second solar wing to Hubble. Grunsfeld and Linnehan added the first wing on Monday. The new array is smaller, but 20-percent more powerful than the old solar wings. Newman and Massimino also installed a new reaction wheel assembly, a device that helps aim Hubble. One of the four devices had a brief outage in November and engineers were worried it might fail again.

After the repair work is complete, Hubble will be released back into space. The 11-day mission is scheduled to end Tuesday with Columbia landing at Kennedy Space Center in Florida.