U.S. astronauts aboard the spaceshuttle Atlantis released the Hubble Space Telescope on Tuesday, after NASA's fifth and final mission to upgrade the orbiting observatory.
Using Atlantis' robotic arm, Mission Specialist Megan McArthur released Hubble at 8:57 a.m. EDT (1257 GMT). A jet firing will be performed in about a half-hour to increase Atlantis' separation rate from the telescope, as the seven crew members bid farewell to Hubble for the final time after working on it for nearly a week.
They installed a new camera and light-splitting spectrograph, replaced Hubble's positioning system, repaired two instruments and attached a docking ring so a robotic spacecraft can be sent to remove Hubble from orbit at the end of its operational lifetime. NASA says it should last another five to 10 years and unlock even more mysteries of the cosmos.
There will be no more repair missions to Hubble. Sometime after2020, NASA will send a robotic craft to steer the telescope into a watery grave.
The astronauts will now inspect their ship before heading home Friday.
Hubble, launched by NASA in 1990, was named after U.S. astronomer Edwin Hubble whose work revolutionized our understanding of the size and structure of the universe.
After its first two months of tests in 1990, the initial images from Hubble were a blurry disappointment. A slight flaw in the telescope's main mirror -- barely the width of a human hair --fouled the observatory's vision.
In 1993, NASA sent a shuttle up to Hubble, where astronauts added corrective lenses -- essentially glasses -- to sharpen its vision. The result was crystal clear: 16 years of stunning cosmic photos followed.
Since that first orbital fix, astronauts returned to Hubble four more times: in 1997, 1999, 2002 and 2009.
Hubble has given the world amazing insight into the origins of our universe. Among its greatest discoveries are determining the age of the universe (13.7 billion years); finding that virtually all major galaxies have black holes at their center; discovering that the process of planetary formation is relatively common; detecting first ever organic molecule in the atmosphere of a planet orbiting another star; and providing evidence that the speed at which the universe is expanding is accelerating – caused by an unknown force that makes up more than 75 percent of the universe.