The shuttle Atlantis took off from Cape Canaveral, Florida, just after 2 p.m. Monday loaded with seven astronauts and hundreds of millions of dollars' worth of shiny new equipment for the Hubble Space Telescope.
With a roar of the engines, Atlantis took off from Kennedy Space Center to the delight of about 30,000 onlookers.
"Let's launch Atlantis," Commander Scott Altman said just before liftoff.
"Enjoy the ride, pal," replied launch director Mike Leinbach.
The crew got a scare a few minutes into the flight, as a malfunctioning sensor indicated a problem. However, Mission Control repeatedly assured Altman that the shuttle was fine.
The Atlantis is loaded with almost 2 million litres of fuel for the fifth and final mission to repair the aging telescope.
The shuttle and its crew are scheduled to arrive at the observatory on Wednesday.
The 11-day mission will include five spacewalks to repair the 19-year-old telescope and keep it going long enough until a replacement telescope, the James Webb, can be launched in 2014.
Hubble has been left unattended for seven long years. It's the longest gap ever between servicing missions and was created in large part by the 2003 Columbia disaster, which grounded all shuttle missions for a time.
After the Columbia accident, NASA changed its approach to space missions and set up the International Space Station as an emergency shelter for astronauts in the event that a spaceship became too damaged to attempt the flight home.
With this mission, the use of the space station as a safe harbour won't be possible, explained space expert Randy Attwood.
"There isn't that opportunity with this mission because once you're in Hubble's orbit, you can't get to the Space Station; they're in two different orbits," he told Canada AM Monday morning.
"That's why you see Endeavour on the other pad, ready to go and assist and rescue the astronauts, if for some reason they're needed -- but it's very, very unlikely; it's more for making everyone feel comfortable."
The mission carries with it considerable danger. Satellite collisions and break ups have left space littered with junk that could damage the shuttle.
As a result, the Endeavour will be on standby until the Atlantis begins its return flight home on May 22.
Attwood says assuming all goes smoothly, the real drama will be the five scheduled spacewalks.
"They're jam-packed with a lot of aggressive work," he says of each of the six-hour spacewalks.
The repairs are badly needed. Both the telescope's main camera and a spectrograph have died. Three of six stabilizing gyroscopes are on the fritz. Even without all the failures, the Hubble had been working with most of the same technology it came with when it was designed back in the 1970s.
Retired U.S. air force colonel and former astronaut Jim Kelly said that the repairs and updates should extend the life of the telescope for at least another five to seven years.
"When all is said and done, some of the instruments that are on there will be 90 times more powerful than the originals that were on there in the 1990s," Kelly said Monday on Â鶹´«Ã½net from Cape Canaveral. "So it will be like a brand new telescope in some ways."
The astronauts will have their work cut out for them with all the precision work needed to remove about 220 screws and install new memory cards -- all while outfitted in space suits.
"Imagine doing that fine work with your oven mitts on," laughed Attwood. "These things weren't designed to be fixed, so that'll be a challenge. They're going to have a lot of work."
Hubble History
The Hubble Space Telescope, a US$10 billion project, launched amid great fanfare in 1990, but soon proved to have serious flaws.
A defective mirror on the telescope led to blurry images, and so corrective lenses had to be installed during a 1993 mission.
Since then, the Hubble is credited with providing images and data to scientists that have allowed them to learn a great deal about the universe, including its age: 13.7 billion years.
"Hubble has been changing astronomy textbooks everywhere," Attwood told Â鶹´«Ã½net shortly before the shuttle's launch. "We've learned new things about the planets, about nearby galaxies, about the beginning of the universe, the age of the universe. We now know that there are black holes in the middle of galaxies, and the list goes on and on."
With files from The Associated Press
