Astronauts onboard the shuttle Atlantis said their last goodbyes to the Hubble Space Telescope this morning.
After five grueling spacewalks and extensive repairs, NASA astronauts released the telescope back into orbit. The 19-year-old Hubble Space Telescope will never again undergo a servicing mission in space.
"Not everything went as we planned but we found a way to work around it," Cmd. Scott Altman said after the shuttle released Hubble. "We did it together and now Hubble can continue on its own exploration of the cosmos and bring it home to us as we head for home in a few days."
Thanks to the astronauts' repairs, the telescope should be able to photograph the cosmos for another five or more years. NASA expects to launch the more advanced James Webb Space Telescope in 2014. When Hubble retires, this new telescope will pick up from where it left off.
"Congratulations on a great series of spacewalks," Dan Burbank, the spacecraft communicator, told the Atlantis crew.
After additional tests and preparations this week, the astronauts are scheduled to return on Friday.
It will be three months before scientists know how well all the new instruments work. The Goddard Space Flight Center in Maryland will unveil the new discoveries after Hubble's renovation Sept 7. In total, this Hubble mission cost more than $1 billion.
"We fought against tremendous odds to fly this mission, and we succeeded beyond our wildest dreams," chief Hubble scientist Dave Leckrone said after the spacewalk ended.
Astronauts John Grunsfeld and Drew Feustal started work an hour early Monday. During the spacewalk, the duo installed a new set of batteries, a Fine Guidance Sensor that helps aim the telescope and protective steel-foil sheets on the telescope's exterior.
Earlier in the mission, astronauts Mike Massimino and Mike Good were tasked with installing the steel New Outer Blanket Layer Sunday, but were unable to accomplish it because the spacewalk fell three hours behind.
The team was asked to fix a spectrograph that can, among other things, measure the chemical composition of distant objects in the cosmos. To accomplish this, Massimino had to remove more than 110 small screws which, with huge space gloves, proved to be a tedious, time-consuming task.
At one point, Houston sent Massimino back to the space shuttle's airlock to refill the oxygen in his backpack. In the end, the astronauts wrapped up what was scheduled as a 6½-hour spacewalk after eight hours.
Grunsfeld and Feustel whipped through what was supposed to be the toughest spacewalk of the mission Saturday to repair the Hubble Space Telescope with remarkable ease.
The two replaced an old instrument with the new Cosmic Origins Spectrograph, and then repaired a broken camera deep inside the telescope, removing blown circuit boards that were never meant to be taken off in orbit.