NASA's Mars-bound spacecraft lifted off Saturday morning, carrying a six-wheeled rover that will explore the Red Planet.

The unmanned Atlas 5 rocket took off from Cape Canaveral, Florida around 10 a.m. ET.

The $2.5-billion US mission will see a car-sized rover, officially called the Mars Science Laboratory but nicknamed Curiosity, land on Mars in roughly 8½ months after a journey of some 570 million kilometres.

The nuclear-powered mobile laboratory — holding 10 science instruments, including one designed and built in Canada — will sample Martian soil and rocks, and analyze them right there on the surface. The mission is expected to last for at least two years.

With a length of 3 metres and weighing 899 kilograms, Curiosity dwarves the golf cart-sized Spirit and Opportunity Mars rovers that landed in 2004.

"It’s not your father’s rover," Doug McCuistion, director of NASA's Mars program, said in a media briefing earlier this month.

Curiosity will land in the Gale Crater — which scientists believe may have once been a lake — in search of evidence of water and microbial life. The area is also particularly rich in minerals.

CBC's Bob McDonald said the mission will be trying to detect faint traces of organic compounds which, if discovered, would prove to be a huge success.

"If they do find signs of life of Mars that'll be the first indication that we're not alone in the universe," he said. "It's a rather big question."

Canadian component

One of Curiosity's 10 scientific tools is the APXS (alpha particle X-ray spectrometer), a $17.8 million device that will be used to identify chemical elements in Martian rock and soil.

It was designed by University of Guelph physics professor Ralf Gellert and built by Richmond, B.C.-based MacDonald, Dettwiler and Associates Ltd.

Alain Berinstain from the Canadian Space Agency said the APXS provides a modest but critical element of the mission, similar to the role played by the robotic Canadarm.

"It'll help contribute to the overall science goals of the mission," he told CBC News.

Lowered to planet with jet pack

A Mars frenzy gripped the launch site, with more than 13,000 guests jamming the space centre for NASA's first launch to Earth's next-door neighbour in four years, and the first send-off of a Martian rover in eight years.

The world has launched more than three dozen missions to the ever-alluring Mars, which is more like Earth than the other solar-system planets. Yet fewer than half those quests have succeeded.

Just two weeks ago, a Russian spacecraft ended up stuck in orbit around Earth, rather than en route to the Martian moon Phobos.

"Mars really is the Bermuda Triangle of the solar system," Hartman said.

Curiosity's arrival next August will be particularly hair-raising.

In a spacecraft first, the rover will be lowered onto the Martian surface via a jet pack and tether system similar to the sky cranes used to lower heavy equipment into remote areas on Earth.

With files from The Associated Press