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On the eve of landing day, mission control was quiet with only a handful of flight controllers on duty. Two jars of peanuts were on display on the front console. As the countdown to landing nears, the place will be humming.

“I get butterflies every now and then,” said flight director Keith Comeaux.

If successful, Curiosity will join another roving spacecraft, Opportunity, which has been exploring Mars since 2004.

The most high-tech Mars spacecraft ever built, the nuclear-powered Curiosity is equipped with more than a dozen cameras, a weather station and tools to drill, taste and sniff the environment in search of the chemical building blocks of life.

Its target is Gale Crater near the equator, which scientists think is a place where water once flowed _ a good starting point to learn whether microbes could exist there. Rising from the floor of Gale is an impressive mountain where mineral signatures of water have been spied at the base.

Life as we know it requires three ingredients: Water, energy and carbon. The missing piece so far is finding carbon. One of Curiosity’s main tasks is to drive to the mountain, chisel rocks and dig into soil in search of the elusive element.

During its cruise to Mars, Curiosity turned on its radiation sensor and sent back data, which should help scientists better understand the risks that astronauts would face on a manned mission.

Before Curiosity can further explore, it must first stick the landing.

Weighing nearly 2,000 pounds, it is much heavier than Opportunity and can’t bounce to a stop swaddled in air bags; it would break apart if it did. So engineers devised a new trick. Sunday will be the first time that the novel landing routine will make its debut.

Engineer Steve Sell said his eyes will be glued to his computer screen on landing day.

“I just have to keep reminding myself to keep breathing,” Sell said.

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Follow Alicia Chang’s Mars coverage at: http://www.twitter.com/SciWriAlicia