From Earth to Gale: Curiosity aims for Martian dry lake bed
BY STEPHEN CLARK
Posted: November 21, 2011
The Curiosity rover is heading for a potential Martian dry lake bed the size of Los Angeles adorned with ragged rock formations and a colossal three-mile-high mountain.
"It will be a lot like areas in the Southwest [United States], places like Monument Valley where we'll see these big cliffs with the rover going between them," said Dawn Sumner, a geologist at the University of California, Davis.
The 96-mile-wide Gale crater is marked with clays and sulfates at the base of a 15,000-foot-tall mountain. If the mission lasts long enough, Curiosity could climb the mound and study a range of minerals from long ago.
"In one location, we can drive the rover through all these successive different environments and sample these different periods in Martian history," said John Grotzinger, the chief researcher for the Curiosity rover at NASA's Jet Propulsion Laboratory in Pasadena, Calif.
Curiosty will take a set of stereo eyes, a sensor-laden robotic arm with a scoop, and instruments to smell and taste soil in search of organic molecules, the building blocks of life. The rover even carries a microscope and a laser to zap rocks from several feet away.
Liftoff is scheduled for Saturday aboard an Atlas 5 rocket launched from Cape Canaveral, Fla.
After considering 60 landing site candidates, scientists recommended Gale crater as Curiosity's destination because it offered the widest array of geologic research opportunities, giving the rover a window into a large period of Martian history.
"There was a preference for Gale in that it's not a one-trick pony," said Michael Meyer, the lead scientist for NASA's Mars programs. "There are several different environmental settings that can be explored, any one of which might have the possibility of [holding] organic compounds."
Positioned just south of the Martian equator, the crater's central peak is taller than any mountain in the continental United States.
After touching down on relatively flat terrain a few miles from the base of the mound, Curiosity will drive south toward the peak and begin to climb thousands of feet up its flank, pausing to examine clay and sulfate salt minerals along the way, Grotzinger said.
Dried-up stream channels along the edge of the mound will allow access up the mountain.
Curiosity's mission is supposed to last two years after landing, but scientists are hopeful the rover will continue the climb up Gale's lofty mountain for years more. Scientists say the most attractive scientific targets are near the base of the central mountain, ensuring the rover will produce quality results early in the mission.
The rover's mobility system has the ability to climb a 20-degree incline. It's designed to drive at least 12 miles, according to Michael Watkins, an MSL project engineer at JPL.
"Geologists like climbing up cliffs, and we get to go to those places with this rover for the first time on Mars," Sumner said.
As the rover ascends the mountain, it will encounter rocks and soil left behind as waters receded when Mars transitioned from a warm, wet planet into the cold and desolate world known today.
Curiosity's analysis of clays and sulfates will tell scientists how much water was once present at Gale, the characteristics of the water and how it evaporated, according to Sumner.
Curiosity is not designed to directly detect life or find a fossil. It would have to be "extremely lucky" to find ironclad evidence of life, Meyer said.
But the clay minerals at Gale crater could hold rich deposits of organic compounds and could point scientists closer toward their holy grail of solving the Martian life mystery.
Curiosity's robot arm will dump soil into a sample analysis instrument on the rover's main deck, where an oven and solvents will release chemicals to be observed with laser and mass spectrometers and a gas chromatograph. The high-tech device will sense and characterize carbon-based molecules.
If Curiosity can find elusive carbon-based organic material inside Gale's rocks, scientists will obtain evidence that the ingredients for life were once plentiful on Mars.
NASA selected Gale from four finalists scattered across the Red Planet's surface. Science return and safety were the two primary decision drivers.
Using high-resolution imagery from a sharp-eyed camera on NASA's Mars Reconnaissance Orbiter, the landing site selection committee mapped hazards and plotted driving paths for the rover at each of the four finalist locations.
Spectrometers on orbiting satellites at Mars indicated Gale had the widest variety of environments of all the sites, harboring both relatively fresh and ancient material inside the crater, which scientists believe is about 3 billion years old.
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