Updated at 2:10 p.m. ET
CAPE CANAVERAL, Fla. - Endeavour blasted off on NASA's next-to-last shuttle flight, thundering through clouds into orbit Monday morning as the mission commander's wounded wife, Gabrielle Giffords, watched along with an exhilarated crowd estimated in the hundreds of thousands.
"Good stuff, good stuff," Giffords was quoted as saying by her chief of staff as Endeavour took flight for the final time. Husband Mark Kelly, the shuttle's skipper, had red tulips presented to her afterward. She wore his wedding ring on a silver chain while he carried hers with him.
At 8:56:28 a.m. EDT, Endeavour's twin solid-fuel boosters ignited with a rush of 5,000-degree exhaust, instantly pushing the spacecraft away from pad 39A, CBS News space consultant William Harwood reports.
"Final liftoff for Endeavor, expanding our knowledge, expanding our lives," a NASA announcer said as the shuttle lifted off.
Accelerating through 100 mph -- straight up -- in just eight seconds, Endeavour climbed away and quickly disappeared from view as it knifed through low-level clouds, wheeling about to line up on a northeasterly trajectory paralleling the East Coast, Harwood reports.
NASA is winding down its 30-year-old shuttle program before embarking on something new. The liftoff generated the kind of excitement seldom seen on Florida's Space Coast on such a grand scale despite a delay of more than two weeks from the original launch date because of an electrical problem.
Monday's countdown was close to perfect, and the shuttle quickly disappeared into thin, low clouds.
"That was four seconds of cool," said Manny Kariotakis, who was visiting from Montreal. The 50-year-old day care owner got goosebumps watching the liftoff with thousands along Highway 1 in Titusville.
(At left, a video posted to Twitter shows the Endeavour shuttle launch as seen from a plane window.)
Just before launching, Kelly thanked all those who put hands "on this incredible ship."
"It is in the DNA of our great country to reach for the stars and explore. We must not stop," he said.
Remarkably, Giffords made a return visit to see Kelly off. She is still undergoing rehabilitation in a Houston hospital to recover from a gunshot wound to the head in an assassination attempt little more than four months ago. She has weakness on her right side, and difficulty speaking.
On CBS' "The Early Show" Monday, Giffords' chief of staff, Pia Carusone, said the couple changed their usual pre-launch routine this time.
"Usually," Carusone told co-anchor Erica Hill, "he takes her wedding ring to space. So he took it from her a couple of days ago. But she wanted his. So, yesterday ... he gave her his ring. But his hands are a bit bigger than hers. So it didn't fit on her finger. So, he gave it to me to find a chain to give to her. So, I did last night. It's in my pocket and it will be around her neck as soon as I see her."
The Arizona congresswoman, sitting in a wheelchair, watched the launch in private with her mother and the other astronauts' wives and children atop the Launch Control Center. There were hugs all around after the shuttle rocketed away, said the congresswoman's chief of staff, Carusone.
"It was a real sense of relief from all of us that this went off safely," Carusone said.
Kelly's identical twin Scott, who's also an astronaut, presented red tulips to Giffords, and a single red rose to each of Mark's two teenage daughters from a previous marriage.
Giffords has kept out of the public eye since the Jan. 8 shooting that wounded her and killed six in Tucson, Ariz. She and Kelly said their goodbyes on Sunday.
With Kelly at the helm, Endeavour and its experienced crew of five Americans and an Italian are headed for the International Space Station. They will arrive at the orbiting outpost Wednesday, delivering a $2 billion magnetic instrument that will seek out antimatter and dark energy in the universe.
On Tuesday, the astronauts will survey their ship for any launch damage to Endeavour's thermal shield. Only a couple small bits of insulating foam came off the fuel tank during the crucial phase of liftoff, officials said.
Up to 45,000 guests jammed into NASA's launch site, and thousands packed area roads and towns to see Endeavour soar one last time. Only one shuttle flight remains.
VIPs included Apollo 11's Michael Collins and four other members of Congress.
Advance estimates had put Monday's crowd at 500,000, more than the number that saw Discovery's final hurrah in February. Across the Indian River in Titusville, though, the number of spectators appeared to be down compared with Endeavour's previous launch attempt on a Friday afternoon.
Titusville Assistant Police Chief John Lau guessed the crowd at between 350,000 and 400,000.
"I don't know if it was the early morning or what," Lau said.
Electrical trouble grounded the shuttle on April 29, disappointing the hordes of visitors, including President Obama and his family. Repairs over the past two weeks took care of the problem.
"God Speed Endeavour We're ready for you!" space station resident Ronald Garan Jr. said in a Twitter update. At launch, the space station was 220 miles high, just southeast of Halifax, Nova Scotia.