Curiosity rover will explore 'scenic' Gale crater on Mars
BY STEPHEN CLARK
Posted: July 22, 2011
The next Mars rover will make a pinpoint landing inside Gale crater, a scenic impact site adorned with ragged rock formations and a colossal mountain rising more than 15,000 feet high, NASA announced Friday.
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.
If it launches on time, Curiosity will arrive at Mars on Aug. 6, 2012.
Michael Meyer, the lead researcher for NASA's Mars program, said there was a "slight preference" for Gale among the four landing site finalists. It was likely once home to a deep lake.
"There was a preference for Gale in that it's not a one-trick pony," Meyer said. "There are several different environmental settings that can be explored, any one of which might have the possibility of [holding] organic compounds."
"In the end, we picked the one that felt best," said John Grotzinger, the Mars Science Laboratory mission's chief scientist at the Jet Propulsion Laboratory in Pasadena, Calif.
Geologists do not expect Curiosity to find a fossil on Mars, but it could uncover the chemical fingerprint of past life amid organic compounds.
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.
Previous NASA missions already confirmed water was once common on the surface of Mars. After retreating during a period of climate change, the water is now held in ice caps at the Martian poles and embedded inside mineral compounds in some soils.
The exploration of the scenic 96-mile-wide crater will also return thousands of images from Curiosity's cameras.
"It's also going to be an incredibly beautiful place," said Dawn Sumner, a geologist at the University of California, Davis. "It will be a lot like areas in the Southwest [United States], places like Monument Valley where we'll have these big cliffs with the rover going between them."
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.
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.
"What we've learned is if you start at the bottom of the layers and you work your way to the top, it's like reading a novel," Grotzinger said. "And we think Gale is going to be a great novel."
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.
Curiosity is NASA's first mobile Mars surface station since the Spirit and Opportunity rovers arrived at the Red Planet in 2004.
The rover is five times as massive as the previous generation of Mars robots, and its scientific gear is 10 times heavier.
After braving the hot temperatures of entry into the Martian atmosphere in a blunt heat shield, Curiosity will descend to a hover with a rocket-powered descent stage. A state-of-the-art "sky crane" will lower the nearly 2,000-pound rover on a bridle to the surface directly on its wheels.
The futuristic descent and landing system replaces air bags, a tried-and-true but rudimentary touchdown technique. With the new system, engineers expect to guide Curiosity to a precise landing inside a narrow error corridor.
"We've done our homework," Meyer said. "The engineers have designed a spacecraft to get us to where we want to go."
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.