JPL: Opportunity arrives at Spirit Point, Endeavour Crater

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JPL: Opportunity arrives at Spirit Point, Endeavour Crater

Post by bystander » Wed Aug 10, 2011 7:24 pm

NASA Mars Rover Arrives at New Site on Martian Surface
NASA JPL-Caltech | Opportunity | 2011 Aug 10
After a journey of almost three years, NASA's Mars Exploration Rover Opportunity has reached the Red Planet's Endeavour crater to study rocks never seen before.

On Aug. 9, the golf cart-sized rover relayed its arrival at a location named Spirit Point on the crater's rim. Opportunity drove approximately 13 miles (21 kilometers) since climbing out of the Victoria crater.

"NASA is continuing to write remarkable chapters in our nation's story of exploration with discoveries on Mars and trips to an array of challenging new destinations," NASA Administrator Charles Bolden said. "Opportunity's findings and data from the upcoming Mars Science Laboratory will play a key role in making possible future human missions to Mars and other places where humans have not yet been."

Endeavour crater, which is more than 25 times wider than Victoria crater, is 14 miles (22 kilometers) in diameter. At Endeavour, scientists expect to see much older rocks and terrains than those examined by Opportunity during its first seven years on Mars. Endeavour became a tantalizing destination after NASA's Mars Reconnaissance Orbiter detected clay minerals that may have formed in an early warmer and wetter period.

"We're soon going to get the opportunity to sample a rock type the rovers haven't seen yet," said Matthew Golombek, Mars Exploration Rover science team member, at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, Calif. "Clay minerals form in wet conditions so we may learn about a potentially habitable environment that appears to have been very different from those responsible for the rocks comprising the plains."

The name Spirit Point informally commemorates Opportunity's twin rover, which stopped communicating in March 2010. Spirit's mission officially concluded in May.

"Our arrival at this destination is a reminder that these rovers have continued far beyond the original three-month mission," said John Callas, Mars Exploration Rover project manager at JPL.

Mars rover reaches rim of vast, ancient crater
New Scientist | David Shiva | 2011 Aug 10

Mars Rover Reaches Giant Crater After 3-Year Trek
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NASA Rover Arrives at Huge Mars Crater After 3-Year Trek
Space.com | Denise Chow | 2011 Aug 10
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alive to the gentle breeze of communication, and please stop being such a jerk.
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Re: Opportunity arrives at Spirit Point, Endeavour Crater

Post by neufer » Wed Aug 10, 2011 8:15 pm

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Opportunity Begins Study of Martian Crater

Post by bystander » Thu Sep 15, 2011 11:14 am

Opportunity Begins Study of Martian Crater
NASA JPL-Caltech | Opportunity | 2011 Sept 01
The initial work of NASA's Mars rover Opportunity at its new location on Mars shows surface compositional differences from anything the robot has studied in its first 7.5 years of exploration.

Opportunity arrived three weeks ago at the rim of a 14-mile-wide (22-kilometer-wide) crater named Endeavour. The first rock it examined is flat-topped and about the size of a footstool. It was apparently excavated by an impact that dug a crater the size of a tennis court into the crater's rim. The rock was informally named "Tisdale 2."

"This is different from any rock ever seen on Mars," said Steve Squyres, principal investigator for Opportunity at Cornell University in Ithaca, N.Y. "It has a composition similar to some volcanic rocks, but there's much more zinc and bromine than we've typically seen. We are getting confirmation that reaching Endeavour really has given us the equivalent of a second landing site for Opportunity."

The diversity of fragments in Tisdale 2 could be a prelude to other minerals Opportunity might find at Endeavour. In the past two weeks, researchers have used an instrument on the rover's robotic arm to identify elements at several spots on Tisdale 2. Scientists have also examined the rock using the rover's microscopic imager and multiple filters of its panoramic camera.

Observations by Mars orbiters suggest that rock exposures on Endeavour's rim date from early in Martian history and include clay minerals that form in less-acidic wet conditions, possibly more favorable for life. Discontinuous ridges are all that remains of the ancient crater's rim. The ridge at the section of the rim where Opportunity arrived is named "Cape York." A gap between Cape York and the next rim fragment to the south is called "Botany Bay."

"On the final traverses to Cape York, we saw ragged outcrops at Botany Bay unlike anything Opportunity has seen so far, and a bench around the edge of Cape York looks like sedimentary rock that's been cut and filled with veins of material possibly delivered by water," said Ray Arvidson, the rover's deputy principal investigator at Washington University in St. Louis. "We made an explicit decision to examine ancient rocks of Cape York first."

The science team selected Endeavour as Opportunity's long-term destination after the rover climbed out of Victoria crater three years ago this week. The mission spent two years studying Victoria, which is about one twenty-fifth as wide as Endeavour. Layers of bedrock exposed at Victoria and other locations Opportunity has visited share a sulfate-rich composition linked to an ancient era when acidic water was present. Opportunity drove about 13 miles (21 kilometers) from Victoria to reach Endeavour. It has driven 20.8 miles (33.5 kilometers) since landing on Mars.

"We have a very senior rover in good health for having already worked 30 times longer than planned," said John Callas, project manager for Opportunity at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "However, at any time, we could lose a critical component on an essential rover system, and the mission would be over. Or, we might still be using this rover's capabilities beneficially for years. There are miles of exciting geology to explore at Endeavour crater."
...
"This is like having a brand new landing site for our veteran rover," said Dave Lavery, program executive for NASA's Mars Exploration Rovers at NASA Headquarters in Washington. "It is a remarkable bonus that comes from being able to rove on Mars with well-built hardware that lasts."

Endeavour crater provides possible evidence of past water
Cornell University | 2011 Sept 02
The Mars rover Opportunity is a senior citizen, but still spry, and as it peers over the rim of the giant impact crater called Endeavour, it's embarking on what could be called a new mission, say its NASA guides.

"You're coming along with us to a brand new geologic field site," said Steve Squyres, Cornell's Goldwin Smith Professor of Astronomy and principal investigator of the Mars Exploration Rover mission, addressing reporters during a Sept. 1 news teleconference.

Squyres joined fellow Mars scientists from the Jet Propulsion Laboratory in Pasadena, Calif., and NASA headquarters in Washington to brief reporters on expectations for Opportunity's investigation of Endeavour crater. It arrived Aug. 9 at Cape York, on the rim of Endeavour, after a three-year journey of about 13 miles as it detoured to avoid numerous hazards along the way.

Endeavour is an impact crater 14 miles in diameter. It offers tantalizing clues about the Red Planet's early formative process, according to the scientists. Squyres described Tisdale 2, the first rock Opportunity has examined at the rim of Endeavour. It is a breccia -- composed of chunks of fragmented rock, and pretty much what the team would expect to find in that location, Squyres said. However, it has the scientists excited because it's unlike any rock they've explored so far on Mars.

Tisdale 2 is a basaltic rock that has a composition similar to some volcanic rocks, but most striking so far is the large amount of zinc in its chemical makeup, Squyres said. For rocks on Earth, zinc is an element typically associated with being formed in a place with hydrothermal activity.

"This is a clue ... that we may be dealing with a hydrothermal system here," Squyres said. "We may be dealing with a situation where water has percolated or flowed or somehow moved through these rocks -- maybe as vapor or maybe as liquid. We don't know yet."

It is too early to tell whether the rock's composition indicates evidence of water on Mars, Squyres said, but the initial observations point to what he expects will be a "long and interesting story about these rocks."

Opportunity will next drive northeast to search for bedrock along Cape York. Questions to be answered, according to Squyres: Does the zinc composition vary from place to place? Is it concentrated along fractures where water can move easily? Does the zinc correlate with other elements also associated with moving water?

At Mars Crater, NASA Rover Finds Evidence of Ancient Water Hotspot
Space.com | Mike Wall | 2011 Sept 01

NASA Robot arrives at ‘New’ Landing Site holding Clues to Ancient Water Flow on Mars
Universe Today | Ken Kremer | 2011 Sept 03
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alive to the gentle breeze of communication, and please stop being such a jerk.
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Opportunity Inspects Next Rock at Endeavour

Post by bystander » Thu Sep 15, 2011 11:27 am

Opportunity Inspects Next Rock at Endeavour
NASA JPL-Caltech | Opportunity | 2011 Sept 14
NASA's Mars Exploration Rover Opportunity is using instruments on its robotic arm to inspect targets on a rock called "Chester Lake."

This is the second rock the rover has examined with a microscopic imager and a spectrometer since reaching its long-term destination, the rim of vast Endeavour crater, in August. Unlike the first rock, which was a boulder tossed by excavation of a small crater on Endeavour's rim, Chester Lake is an outcrop of bedrock.

The rocks at Endeavour apparently come from an earlier period of Martian history than the rocks that Opportunity examined during its first seven-and-a-half years on Mars.

Chester Lake differs from the first rock inspected by Opportunity on the Endeavour rim, "Tisdale 2," which is a boulder excavated during an impact event that produced a small crater on the rim. Both rocks appear to be breccia, a type of rock fusing together broken fragments of older rocks. By Sol 2713 (Sept. 11, 2011), researchers had used Opportunity's microscopic imager and alpha particle X-ray spectrometer to study Chester Lake and were planning to use the rover's rock abrasion tool and, possibly, its Moessbauer spectrometer on the rock. They will use all the data to reconstruct the chemistry, mineralogy and geologic setting of Chester Lake, including evidence about whether or not the rock has any clay minerals in its composition.

Opportunity on verge of new discovery
Washington University, St. Louis | 2011 Sept 14
Mars rover poised on rock that may yield yet more evidence of a wet Mars hortly after Labor Day 2011, the Mars rover Opportunity was poised on the rim of the 22,000 meter-wide Endeavour Crater, preparing to sample a novel rock type. Much older than the sedimentary samples the rover’s “tasted” so far, this new sample is flush with the promise of revealing clues to the planet’s environment when running rivers coursed the surface.

What was supposed to have been a 90- to 180-day exploration of two distinct regions of the red planet has turned into a saga that has become one of science’s most compelling and long-lasting adventures (now into its eighth year), enthralling the public and the science communities alike.

Launched the summer of 2003 and landing in January 2004, the solar-powered Mars Exploration Rovers (MER) Spirit and Opportunity completed their intended basic missions in April 2004. Each continued roving until March 2010, when Spirit, mired in unexpected but scientifically interesting martian sand and pointed in an unfavorable direction to survive the winter dark, gave up the ghost.

Opportunity, on the other hand, remains active, having reached the rim of Endeavour Crater Aug. 9, 2011, knocking at the door of geology different from any it has explored during its first seven-plus years on Mars.

“Opportunity now is in a brand new mission,” says Raymond E. Arvidson, PhD, the James S. McDonnell Distinguished University Professor in Arts & Sciences at WUTL, and MER deputy principal investigator. “In late August, we looked at a rock named Tisdale, with a composition unlike any we’ve seen before. It has an enormous amount of zinc, bromine, phosphorus, chlorine, and sulfur, all elements that are mobile in the presence of water.

“The ancient rim of Endeavour represents a period when there was probably a lot more water on the surface,” Arvidson says. “So, we’re trying to get the chemical, mineralogical and geological setting to ‘back out’ those ancient conditions to reconstruct environmental conditions during this earlier time period.”

The conditions that formed the sandstones Opportunity has sampled over the past seven years represent a kind of drying-out period of Mars. Occasionally wet but usually dry and wind-blown, the sulphur-rich mineral grains formed vast dune fields that were cemented into sandstone over millions of years by occasional seeping groundwater.

But the terrain Opportunity now is sampling — largely buried by lake bed sediments — pops up in places like Endeavour rim and is much older, going back to the earliest days of the planet. That’s some 3.5 to 4 billion years ago in the last stages of heavy bombardment, when Mars was sweeping up the last planetessimals — cosmic dust grains that collided and stuck to each other to form larger bodies. Endeavour is an impact crater produced during that heavy bombardment period.

Arvidson and his WUSTL colleagues also are part of the Compact Imaging Spectrometer for Mars (CRISM) team of the Mars Reconnaissance Orbiter, a craft orbiting Mars with sophisticated instrumentation that helps Arvidson and other NASA scientists determine where Opportunity should try to go next. The CRISM instrument provides spectral information on martian rocks at a super-high resolution that is processed and analyzed at WUSTL.

CRISM spectral data and other orbital data on the part of the Endeavour crater rim named Cape York indicated a good possibility that clay minerals would be found there.

“Clays form in more neutral, less acidic conditions than the sulfate-rich sandstones we’ve been looking at,” Arvidson says. “Our hypothesis is that if there are clay minerals, the water was less acidic and therefore more conducive to life. The presence of zinc, bromine, phosphorus, chlorine, and sulfur in the Tisdale rock is exciting in that it points toward water moving through and altering the rock, although we have no evidence for clay minerals in Tisdale. Further, the Tisdale surfaces were very rough and we were unable to make use of the Rock Abrasion Tool (RAT) to clean off the surfaces to expose fresh materials.

“Thus, we moved on and are now in the thick of the hunt to find these elusive clay minerals by traversing to other rock targets and making detailed measurements, including making chemical and mineralogical observations of natural, brushed, and ground surfaces. The rock Opportunity is sitting over currently is called Chester Lake and will be our first target in which we will use the RAT to progressively expose deeper and deeper surfaces,” Arvidson says.

The key Opportunity instrument to verify the presence of what Arvidson thinks are iron-bearing clays is the Mössbauer spectrometer. This instrument measures the abundance of iron-bearing minerals in martian rocks and soil by probing tiny changes in the energy levels of the iron atomic nucleus in response to its environment. The Mössbauer spectrometer illuminates a rock with a radioactive source of gamma rays tuned to the energy levels in the iron nucleus and then uses the energies of the returning gamma rays to determine the abundance of iron-bearing minerals in the surface rocks.

Because Opportunity’s arm cannot move side to side due to a broken actuator, Arvidson and team members drive the vehicle to a spot where the arm can still place the RAT and in-situ instruments onto the surface.

Opportunity's mast-mounted emission spectrometer is no longer working, and the steering on one of the wheels is rotated in a bit. But Arvidson says the engineering and science teams have met every challenge through diligence and guarded optimism.

“Opportunity is just a really well-made vehicle,” Arvidson says. “It’s way, way beyond warranty. It was supposed to drive about 600 meters and so far it’s gone 33,500 meters in round numbers, and has taken maybe 150,000 pictures by now.

“It’s well-made and has a dedicated team that has eked out every ounce of science that we can get from it. Plus, we’ve been lucky and landed on a terrain that has rocks that contain detailed clues on past environmental conditions,” he says.

“Stay tuned, we have a new mission and expect to make yet more exciting discoveries about the red planet.”
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor