The Mars rover Curiosity, on a quest for signs the Red Planet once hosted the building blocks of life, streaked into the home stretch of its eight-month voyage on Sunday nearing a make-or-break landing attempt NASA calls its most challenging ever.

Curiosity, the first full-fledged mobile science laboratory ever sent to a distant world, was scheduled to touch down inside a vast, ancient impact crater on Sunday at 10:31 pm Pacific time (1:31 am EDT on Monday/0531 GMT on Monday).

Mission control engineers at the Jet Propulsion Laboratory near Los Angeles acknowledge that delivering the one-ton, six-wheeled, nuclear-powered vehicle in one piece is a highly risky proposition, with zero margin for error.

But on the eve of Curiosity's rendezvous with Mars, JPL's team said the spacecraft and its systems were functioning flawlessly, and forecasts called for favorable Martian weather over the landing zone.

After a journey from Earth of more than 350 million miles (567 million km), engineers said they were hopeful the rover, the size of a small sports car, will land precisely as planned near the foot of a tall mountain rising from the floor of Gale Crater in Mars' southern hemisphere.

Flight controllers anticipate clear and calm conditions for touchdown,slated to occur in the Martian late afternoon. There may be some haze in the planet's pink skies from ice clouds, typical for this time of year, with temperatures at about 10 degrees Fahrenheit.

"We're on target to fly through the eye of the needle," Arthur Amador, the Mars Science Laboratory mission manager, told reporters at a briefing on Saturday, as Curiosity hurtled to within 2.8 million miles (4.5 million km) of its destination.

Facing deep cuts in its science budget and struggling to regain its footing after cancellation of the space shuttle program - NASA's centerpiece for 30 years - the agency has much at stake in the outcome of the $2.5 billion mission.

Mars is the chief component of NASA's long-term deep space exploration plans. Curiosity, the space agency's first astrobiology mission since the 1970s-era Viking probes, is designed primarily to search for evidence that the planet most similar to Earth may have once have harbored ingredients necessary for microbial life to evolve.

(Read by Rosie Tuck. Rosie Tuck is a journalist at the China Daily Website.)

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(Agencies)