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Repaired Hubble relaunched from shuttle

Astronaut Megan McArthur, operating the shuttle Atlantis' robot arm, releases the repaired space telescope Tuesday after a historic five-spacewalk overhaul.

The repaired Hubble Space Telescope was relaunched Tuesday from the shuttle Atlantis after a historic fifth and final in-orbit overhaul.

Astronaut Megan McArthur, operating the shuttle's 50-foot-long robot arm, released the 24,500-pound observatory at 8:57 a.m. EDT as the shuttle sailed 350 miles above the west coast of Africa. The repaired telescope now boasts two new instruments, new gyros, fresh batteries, a new science computer, a refurbished star sensor, and two instruments brought back to life by spacewalking astronauts.

"The release of the Hubble Space Telescope confirmed," mission control commentator Kyle Herring said. "Hubble now back on its own for the final time with a gentle release by one, but carrying the fingerprints of hundreds of thousands."

A NASA graphic shows the Hubble prior to release from the shuttle Atlantis. NASA TV

As Atlantis pilot Gregory Johnson slowly backed Atlantis away, commander Scott "Scooter" Altman radioed mission control, confirming a smooth deploy.

"Houston, Hubble has been released, it's safely back on its journey of exploration as we begin steps to conclude ours," Altman said.

Hubble's protective aperture door was opened a few minutes before deploy, at 8:33 a.m. EDT, allowing starlight to once again fall on its famously flawed 94.5-inch primary mirror. But engineers at the Space Telescope Science Institute in Baltimore and the Space Telescope Operations Control Center at NASA's Goddard Space Flight Center in Greenbelt, Md., will need most of the summer to test and calibrate Hubble's new and refurbished instruments and subsystems.

If all goes well, the first pictures from the upgraded telescope will be released in early September.

The release marked a bittersweet moment for NASA and for Hubble fans as the telescope receded into the dark of space, disappearing from view for the last time. With the shuttle program facing retirement after eight more space station assembly flights, no more Hubble visits are currently planned. And no one will set eyes on the telescope again until a final mission, presumably robotic, to drive it out of orbit sometime in the late 2010s or the 2020s.

"Certainly it's going to be for me, a very touching moment," astronomer-astronaut John Grunsfeld, making his third Hubble house call, said before relaunch. "When I first went to Hubble (in 1999), at the end of our three spacewalks, we deployed Hubble on Christmas Day, and I had very mixed feelings. I'd been working for a number of years on the Hubble project, had gone and done two spacewalks on that mission, and felt like I'd just barely gotten to know the Hubble before we had to send it on its way...

"I was privileged to go back again (in 2002) and I felt like I was visiting an old friend. I was convinced at the end of the last mission, as it floated away, that I would never get a chance to see the Hubble again, but I knew somebody would. And of course that got thrown into disarray with the cancellation of the servicing mission on the shuttle, and so here I am, going back to visit an old friend, to give it a new life along with a team of some Hubble repeats, other Hubble huggers, and a new team.

Faced with certain doom in the wake of the 2003 Columbia disaster, when a final shuttle servicing flight was canceled because of safety concerns, Hubble won a new lease on life when former administrator Mike Griffin reinstated Atlantis' mission after the development of heat shield inspection and repair techniques.

Current mission
Over the course of five back-to-back spacewalks since launch from Earth on May 11, the Atlantis astronauts equipped Hubble with a powerful new $132 million camera, a new $88 million spectrograph, six new stabilizing gyroscopes, six fresh batteries, a refurbished fine guidance sensor, and a new science data computer. The astronauts also pulled off two unprecedented repairs, bringing another camera and an imaging spectrograph back to life after failures in 2004 and 2007.

Hubble is now more scientifically powerful than at any point since launch in 1990. And with new gyros and batteries, it should remain operational for at least five more years and possibly more.

"I don't want to be provincial, but I truly believe this is a very important moment in human history, and I think it's an important moment for science," Hubble Project scientist David Leckrone said. "Just using what Hubble's already done as a starting point, it's unimaginable that we won't dramatically go further than that."

After Hubble's release Tuesday, the astronauts faced a busy day of work to inspect the shuttle's reinforced carbon nose cap, wing leading edge panels, and heat shield tiles to make sure no damage has occurred from micro-meteoroids or space debris since a similar inspection the day after launch.

The odds of a catastrophic impact from space debris are higher for the shuttle at Hubble's 350-mile-high altitude, on average about 1-in-229 compared with less than 1-in-300 for a typical flight to the International Space Station at the lab's lower 220-mile-high altitude.

With Hubble safely on its way, Altman and Johnson planned to carry out a rocket firing later in the morning to lower one side of the shuttle's orbit to around 184 statute miles, reducing the risk of impact by about 15 percent.

Because Hubble operates in a different orbit from the space station, the astronauts cannot seek "safe haven" aboard the lab complex if any major problems occur that might prevent a safe re-entry. As a result, the shuttle Endeavour is poised on pad 39B at the Kennedy Space Center, already prepped for an emergency rescue mission if any unrepairable problems are found.

But the kind of damage that might require a rescue mission is more likely during launch than it is from impacts with small, albeit dangerous, pieces of space debris. Tuesday's heat shield inspection is designed to spot any such damage. With post-Columbia repair tools on board, mission managers are confident any relatively minor damage could be repaired without needing a rescue flight.

Assuming no problems are found, the astronauts will enjoy a day off Wednesday before packing up Thursday for the trip home.

Along with lowering the odds of debris impacts, the orbit adjustment will also make it possible to bring Atlantis home one orbit earlier than originally planned, giving the crew three shots at a Florida landing on Friday and improving the odds of getting home ahead of potentially threatening weather. The first landing opportunity will come 10:01 a.m. EDT Friday.