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An unmanned Atlas 5 rocket carrying a $2.5bn NASA Mars probe has lifted off from Cape Canaveral Air Force Station.

The Mars Science Laboratory, a nuclear-powered rover as big as a compact car and nicknamed Curiosity, is scheduled to touch down on the 'Red Planet' on August 6, 2012, and will search for signs of whether it is or ever was suitable for life.

It is powered by a nuclear-driven electrical system and is equipped with 10 of the most intricate scientific instruments ever sent into space.

Quest for water

Curiosity, has 17 cameras and 10 science instruments, including chemistry labs, to identify elements in soil and rock samples to be dug up by the probe's drill-tipped robotic arm.

The base of the crater's mountain has clays, evidence of a prolonged wet environment, said planetary scientist John
Grotzinger of the California Institute of Technology and the mission's lead scientist.

Water is considered to be a key element for life, but not the only one. Previous Mars probes, including the rovers Spirit
and Opportunity, searched for signs of past surface water.

"[The Mars Rover] will also look for evidence of organic material - particularly carbon - which if found will be an amazing discovery"

- Francisco Diego, physicist

With Curiosity, which is twice as long and three times heavier than its predecessors, NASA shifts its focus to look
for other ingredients for life, including possibly organic carbon, the building block for life on Earth.

"It's a long shot, but we're going to try," Grotzinger said before launch.

Francisco Diego from the University of London Observatory told Al Jazeera the instrument will utilise some of the world's most modern technology in trying to decipher what exactly is happening - and what has occurred on the 'Red Planet'.

"So the rover is going to climb a little bit of those sedimentary layers at the bottom - at 1.2km per hour. They are billions of years old and it will reconstruct the way these layers have been building up starting millions of years ago.

"It will also look for evidence of organic material - particularly carbon - which if found will be an amazing discovery," the physicist and astronomer said.

Curiosity is powered by heat from the radioactive decay of plutonium. It is designed to last one Martian year, or 687
Earth days.

Source: Al Jazeera and agencies