May 18, 2013
Mars Opportunity Rover Examines Rock With Unique Composition
redOrbit Staff & Wire Reports - Your Universe Online
NASA´s Mars Exploration Rover Opportunity has discovered a pale rock that has a higher composition of aluminum and silica and a lower concentration of calcium and iron than any other rock it has examined during its time on Mars, the US space agency announced on Friday.
The fractured rock, which is known as “Esperance,” is located in the “Cape York” region of Mars and was said to have been “intensely” altered by water. As a result, NASA officials state that it provides valuable clues about an ancient, wet environment that was potentially favorable for life.
According to Cornell University´s Steve Squyres, principle investigator on the Opportunity mission, the rock was “so important [that] we committed several weeks to getting this one measurement of it, even though we knew the clock was ticking.”
Engineers from NASA's Jet Propulsion Laboratory (JPL) had initially set this week as a deadline to start moving the rover to its next destination, “Solander Point,” where it will spend the next Martian winter.
“What's so special about Esperance is that there was enough water not only for reactions that produced clay minerals, but also enough to flush out ions set loose by those reactions, so that Opportunity can clearly see the alteration,” added Scott McLennan of Stony Brook University, a long-term planner for Opportunity's science team.
Both Solander Point and Cape York are segments of the rim of the 14 mile-across Endeavour Crater, and the planned route to its new destination is approximately 1.4 miles in length. Opportunity has been conducting research at Cape York since arriving in the western edge of Endeavour Crater back in the middle of 2011.
“Based on our current solar-array dust models, we intend to reach an area of 15 degrees northerly tilt before Opportunity's sixth Martian winter,” said mission manager Scott Lever of JPL. “Solander Point gives us that tilt and may allow us to move around quite a bit for winter science observations.”
Opportunity began moving away from Esperance on Tuesday, traveling nearly 82 feet towards its new destination three days after exposing a patch of the rock´s interior with its rock abrasion tool.
The team then used a camera and spectrometer on its robotic arm to examine Esperance, which they identified while exploring an area of Cape York where the Compact Reconnaissance Spectrometer for Mars (CRISM) on NASA's Mars Reconnaissance Orbiter had detected a clay mineral.
“Clays typically form in wet environments that are not harshly acidic,” the US space agency explained in a statement. “For years, Opportunity had been finding evidence for ancient wet environments that were very acidic. The CRISM findings prompted the rover team to investigate the area where clay had been detected from orbit. There, they found an outcrop called ℠Whitewater Lake,´ containing a small amount of clay from alteration by exposure to water.”
“There appears to have been extensive, but weak, alteration of Whitewater Lake, but intense alteration of Esperance along fractures that provided conduits for fluid flow,” added Squyres. “Water that moved through fractures during this rock's history would have provided more favorable conditions for biology than any other wet environment recorded in rocks Opportunity has seen.”
The amount of daily sunshine available for Opportunity will reach winter minimum next February, meaning that the rover needs to be on a favorable slope prior to that time, NASA said. This is because the northerly tilt increases output from its solar panels during the southern-hemisphere winter, they added.