CAPE CANAVERAL, Fla. - The delay-plagued space shuttle Endeavour finally thundered into the heavens on Wednesday, carrying Canada's Julie Payette to the international space station for a historic rendezvous with a fellow Canadian astronaut.

The shuttle lifted off in a deafening, awe-inspiring display of mankind's might following five previous postponements, most of them due to stormy weather.

And yet there were immediate worries: a video camera mounted on the shuttle's external fuel tank showed chunks of debris flying off the tank, hitting Endeavour's fragile heat shield almost two minutes after lift-off.

"The bottom line is we saw some stuff," said Mike Moses, chairman of the mission management team. "Some of it doesn't concern us. Some of it you just can't really speculate on right now."

Engineers will need several days to evaluate launch imagery and perform other tests to ensure there are no problems, he added.

Debris is not unexpected during launch, but the amount of debris seen during Endeavour's ascent was considered unusual.

The sobering development came at the end of a triumphant day that saw thunderstorms rolling through the Cape Canaveral area earlier than usual, with skies clearing for launch time -- a rare act of co-operation this week from Mother Nature.

It was a gesture that added a romantic element to the launch -- Endeavour blasted off on the eve of the 40th anniversary of the liftoff of the first moon landing.

It rumbled into the sky to begin its orbital chase of the space station at the same spot where Apollo 11's Neil Armstrong, Buzz Aldrin and Michael Collins rocketed into history on July 16, 1969.

History was also in the making for Canada. Payette will meet up at the space station on Friday with fellow Canadian astronaut Robert Thirsk, 55, of New Westminster, B.C.

It will be the first time Canada has had two astronauts in space at the same time.

Canadian astronaut Chris Hadfield, watching from a rooftop perch at the seaside Kennedy Space Center, was jubilant as the shuttle finally exploded into space, leaving a kilometre-long trail of smoke in its wake.

"Come on, baby, yes!" he said repeatedly, pumping his fist in the air, as the shuttle seemingly hovered above the launch pad for a moment before blazing off into the sky like a bullet.

The 16-day mission is Payette's second voyage to space -- she was aboard Discovery in 1999. It also represents the 15th Canadian space flight.

"There's nothing routine about standing next to the spacecraft or being strapped in; it's an immense privilege and it's quite awesome," Payette said in a cellphone call from the launch pad shortly before the lift-off.

"It's an absolutely magnificent vehicle; it's incredible."

Hadfield said he was especially thrilled for Payette, the mission's robotic arm expert.

"She's worked extremely hard for almost all of her professional life to get to today," said Hadfield, himself a space shuttle veteran and the first Canadian to walk in space.

"And she's going up to visit someone who's living off of our planet. Canadians are leaving Earth -- that's a huge accomplishment."

Thirsk is spending six months at the space station, laying the groundwork for deploying Canadian robots onto other planets.

He'll no doubt enjoy some of the Canadian treats Payette toted to space with her, including maple butter, maple syrup, maple cookies and Alberta beef jerky.

Endeavour had been grounded five times previously -- twice in June due to a potentially dangerous hydrogen fuel leak, and three times in the past week because of electrical storms that blew too close to the Kennedy Space Center's seaside launch pad.

Payette's presence will represent the last time a Canadian boards a space shuttle.

NASA is scheduled to shut down the space shuttle program in 2010, and will use Russian airlifts to the space station until the next generation of U.S. spacecraft is ready in 2015.

The program has been rocked by two disasters in 126 previous missions. In 1986, Challenger exploded 73 seconds after liftoff, and six years ago, Columbia disintegrated upon re-entry into the Earth's atmosphere.

Endeavour's numerous delays have not helped NASA's tight deadline to complete construction of the space station by the end of next year. Eight shuttle flights are ahead, all geared toward that goal.

The Endeavour mission will feature five spacewalks and complete construction of the Japan's Kibo laboratory. Astronauts will attach a platform to the outside of the Japanese module that will allow experiments to be exposed to space.

The crew is also delivering a new member to the station's six-man team and bringing back to Earth a Japanese astronaut who's been there since March.

When the shuttle arrives at the space station, there will be a total of 13 people there -- the most ever at the orbital outpost.

Payette's husband, Billie Flynn, said he's seen numerous shuttle launches -- although he was bombing Kosovo when his wife headed to space a decade ago -- and they never cease to amaze him.

"This is a big inspirational thing," said Flynn, a fighter pilot.

"I don't care who you are, how nonchalant you are about things in life, if this doesn't inspire you, seeing a shuttle go up, then nothing will. It just rocks your world. It's astonishing."