Nasa Prepares For Mars Mission Launch

Final preparations are being made to launch the most sophisticated extra-terrestrial science laboratory ever built on a 350-million-mile trip to Mars.

Curiosity, a car-sized robotic rover, has been fixed into position on top of an Atlas rocket that is due to lift off from Cape Canaveral in Florida on November 25.

The six-wheel buggy is five times heavier than any previous explorer sent to Mars.

It is packed with a drill, laser, robotic arm and HD cameras to study the surface of the Red Planet in greater detail than any previous mission.

Doug McCuistion, director of the Mars Exploration Programme , said: "This is the largest and most complex piece of equipment ever put on another planet. It is a wonder of engineering."

The spacecraft is expected to reach Mars in August 2012, when its descent will initially be slowed by a parachute.

Rocket thrusters will then take over, allowing the craft to hover while a 'skycrane' lowers Curiosity 20 metres to the surface.

Project manager Pete Theisinger said the complex landing system was needed because the rover is too heavy for the airbag cushions used on previous missions.

"Any entry, descent and landing on Mars is a place where you take (a) pause and bite your nails a bit," he said.

"It's not a risk-free environment."

Nasa has selected a landing site in the Gale Crater, at the base of a three-mile high mountain.

The rock face exposes several layers of sediment.

"The entire early history of Mars is here for us," said deputy project scientist Ashwin Vasavada.

"We will drive out and climb this mountain with Curiosity. We are looking for environments capable of supporting life."

The nuclear-powered rover will drill into rocks and test samples in its two on-board laboratories. It will study the mineral content and look for organic material.

Nasa hopes to follow up the two-year mission with robots that will bring back soil and rock samples to Earth. It is thought human exploration of the planet could happen in 20 to 30 years.