(NEW YORK) -- NASA's Mars Curiosity Rover came closer and closer to its target on Friday, with all systems go for a landing on Mars Monday at 1:31 a.m. EDT.
Curiosity is the largest, most expensive and most ambitious Mars probe sent by the United States in a generation. It's been a decade in the making and ran up bills of $2.5 billion.
NASA is playing down expectations, but if the building blocks of life are buried in the Martian soil, Curiosity's miniature onboard chemistry laboratory is designed to pick them out.
"We have to keep looking," said Andrew Kessler, a writer who spent three months covering the team that made the last successful landing, in 2008. "Every question leads to more understanding."
Curiosity weighed 5,293 pounds on Earth. It's the size of a small car and much bigger than the twin rovers Spirit and Opportunity, which landed on Mars in 2004, cradled in airbags. Curiosity is simply too big for that, so it will be lowered to the surface by a heat shield, then a parachute, then retro-rockets, and finally a rocket-powered sky crane. That's something engineers have never tried before.
"When people look at it, it looks crazy," says Adam Stelzner, an engineer who laid out the landing plans, in a video NASA produced about the landing. "Sometimes when we look at it, it looks crazy. It is the result of reasoned engineering thought. But it still looks crazy."
NASA says it thinks there's a 90 percent chance of a safe landing. If that prediction is right, the agency says it hopes Curiosity will explore for one Martian year -- about 22 months on Earth.
If Curiosity doesn't find evidence of life, scientists say it will mean very little. The half-dozen probes to land on Mars since 1976 have only explored a few square miles of the planet.
But what if it really does find something? The results would probably not be conclusive, but they would be incentive for further exploration -- a tender subject at NASA because, hampered by budget cuts, it currently has no future Mars missions approved.
"If we don't ponder these things, then we're not asking ourselves the right questions," said Kessler, "and we're not looking to build bigger and better futures for ourselves."
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