"Now and only now can we declare this mission a total success - the astronauts are safely on the ground," NASA sciences chief Ed Weiler told a Florida press conference.
Atlantis' crew had waited since Friday for the go-ahead to land as Mission Control hoped to avoid the time and expense - about $1.8 million - of diverting to California's Edwards Air Force Base.
The Florida weather refused to yield and Mission Control finally directed shuttle commander Scott Altman to head to California. The shuttle's twin sonic booms rocked the Mojave Desert as it swooped out of a dazzling morning sky.
Out on the runway after landing, Altman reflected on how long it had taken to get their mission under way - and then to end it.
"When we got down to Florida I looked at everybody and said, 'At last,"' Altman said. "I didn't realize it was going to be so hard to get back to the Earth in the end. So again I guess I say the same thing, at last we're back on the ground."
It was the 53rd shuttle landing at Edwards; the last one was in November.
The crew finally set foot on the ground about two hours after touchdown, receiving greetings from ground personnel before they began the customary walkaround to inspect the exterior of their spacecraft. It was uncertain whether the crew would return to their Houston homes later Sunday or on Monday.
NASA officials said it will take about a week to prepare Atlantis for its ferry flight back to Kennedy Space Center atop a NASA Boeing 747.
During five spacewalks, the astronauts gave the 19-year-old Hubble new science instruments, pointing devices and batteries, and fixed broken instruments. The astronauts overcame stuck bolts and other difficulties.
The work will add years to the life of the telescope and its study of the universe.
Initial checkouts of the repaired Hubble were going well, Weiler said. He noted that the telescope had yet to see any starlight but he said he expected it to gather data by August.
Much was made of Atlantis' departure from Hubble as the last time it will be touched by humans, and Weiler acknowledged that was an "emotional moment." But he wanted nothing to do with sad thoughts.
"Geez!" he exclaimed. "We just repaired the Hubble Space Telescope. We got a new telescope, four new instruments, two of them dead now alive. We've got another five, six, seven, eight years with the new telescope. These are truly the best of times not the worst of times."
NASA eventually expects to steer Hubble into the Pacific sometime in the early 2020s using a robotic vehicle, though it's possible that might be done with a crewed vehicle, NASA's new Orion.
The astronauts brought back Hubble's old wide-field camera they pulled out, so it can be displayed at the Smithsonian Institution. The replacement camera and other new instruments will enable Hubble to peer deeper into the universe.
The $1 billion repair mission almost did not happen. It was canceled in 2004, a year after the Columbia shuttle tragedy, because of the dangers of flying into a 350-mile-high orbit that did not offer any shelter in case Atlantis suffered damage from launch debris or space junk. The public protest was intense, and NASA reinstated the flight after developing a rescue plan and shuttle repair kits.
Shuttle Endeavour was on standby for a possible rescue mission until late last week, after inspections found Atlantis' thermal shielding to be solid for re-entry. Endeavour now will be prepped for a June flight to the international space station.
Meanwhile, 19 years after helping launch the Hubble Space Telescope, Charles F. Bolden Jr., a former fighter pilot, Marine Corps major general and veteran space shuttle commander, has been selected by the Obama administration to . Lori Garver, a former NASA associate administrator for policy and plans and a space policy advisor to the Obama campaign, will serve as Bolden's deputy, CBS News space consultant Bill Harwood reports.
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