Most elaborate Mars probe ever, Curiosity will seek building blocks of life beneath Mars' surface

Two lead scientists for NASA's newest Mars rover explain the prospect of finding life on the Red Planet. The rover will dig under the Martian surface in search of the building blocks of life.
Two lead scientists for NASA's newest Mars rover explain the prospect of finding life on the Red Planet. The rover will dig under the Martian surface in search of the building blocks of life.
Mae Ryan/KPCC

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KPCC reporters have been talking to Southland scientists and engineers and counting down the days until NASA's most ambitious rover yet — Curiosity — prepares to land on the Martian surface. Follow the series online.

During a made-for-TV demonstration last week, deputy project scientist Joy Crisp watched two Curiosity rovers climb over rocks in the "Mars Yard" — a test yard at the Jet Propulsion Laboratory in Pasadena.

One rover, called Scarecrow, weighs what the Curiosity rover will weigh when it lands on Mars. It's smaller than the other one, a full-scale replica of Curiosity, down to the laboratory instruments. Both rovers roll across sand and climb over rocks the same way that their traveling brother can.

And like the larger Curiosity rover, these machines aren’t equipped to find Martians. On the Red Planet, even tiny microbes will be hard to come by.

“We’re not exactly looking for life because we don’t yet know how to design an instrument to look for life,” said Crisp.

“We’re looking for signs that could life have thrived in such an environment. Did it have the building blocks necessary?”

Curiosity will drill down a full four inches deep into Martian soil to search for carbon, hydrogen, oxygen, phosphorus – the organics that made up Earth’s primordial ooze.

In May, a handful of JPL scientists brought the Scraecrow backup rover to Death Valley’s Dumont Dunes. Usually the dunes are teeming with four wheelers – but for the test, only the six-wheeled rover inched up a sandy incline.

John Grotzinger, the lead scientist on the Curiosity project, peered past his baseball cap and sunglasses to watch the rover roll along in 104-degree heat.

On Mars, heat isn’t the problem; freezing cold is. But is it too cold for life? Or too dry? What does Earth have that Mars doesn’t?

Grotzinger, who’s a geologist at Caltech, studies early evolution on Earth.

“One of the questions we always ask is what happens if we replayed the tape from the beginning on Earth?” said Grotzinger. “Would we get life that would look like us? Would we get the whole sequence of evolution as we understand it on Earth?”

The average surface temperature on Mars is 64 degrees below zero; the atmosphere is 95 percent carbon dioxide and there’s no liquid water on the surface.

But scientists think the Mars of 3.5 billion years ago had abundant water and massive volcanoes. Conditions might have been right for microbial life. Crisp says maybe organic materials are still embedded in Curiosity’s new stomping grounds: Gale Crater.

Gale Crater is filled with sand dunes. In the middle, Mt. Sharp rises up at a steady rover-friendly incline. The mountain has layers upon layers of sediment from past Martian environments; at its base, there could be mineral deposits from water that might include carbon-based molecules.

“So Gale Crater has a very thick sequence of layered rocks,” said Crisp. “It’s about three miles in thickness so that’s beyond what we see in the Grand Canyon in layers.”

The chance of finding carbon compounds is slim, but the Mars team has some cool sci-fi tricks it can use. Unlike its predecessors Spirit and Opportunity, Curiosity has a laser that can fire from the top of the mast. Crisp said scientists can point it at rocks and soils to blast away a little tiny spot and turn the rock or soil into a plasma

Solar radiation that’s bombarded the Red Planet for billions of years probably wiped out most traces of life. Crisp and other scientists who will study Curiosity’s data hope that below the surface, carbon-based molecules were shielded – and are still there.

“We’re actually bringing a radiation measuring instrument to check out what the current radiation conditions are,” said Crisp. “One of the questions we want to ask is: how do organic compounds hold up?”

The radiation measurements will factor into how to design spacesuits for a human expedition to Mars.

But don’t get too excited; no one’s booking a trip to Mars anytime soon – and it’s not because no one’s built the right spacesuit.

“With the difficult economic times that we’re in, that doesn’t seem likely that we would send people to Mars in 20 years,” said Crisp. “But who knows?”

Even if we get the spacesuits figured out, if we ever want to call Mars home, we’ll need a source of water on the dusty planet. Caltech’s Grotzinger knows that’s a challenge - and maybe an opportunity.

“Right now we’re thinking of water from the point of view of would microorganisms have had access to it to live,” said Grotzinger.

“But the other question you can ask with the water is, 'could we somehow farm this water to use for humans if we ever made it to Mars?'”

Still, irrigating Martian settlements or farms is a good century or more away. For now, the Curiosity rover is going to take it six wheels at a time.