Mars Rover Curiosity

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11.11.2015

Upgrade Helps NASA Study Mineral Veins on Mars

Diverse composition of mineral veins at the "Garden City" site investigated by NASA's Curiosity Mars rover suggests multiple episodes of groundwater activity.

Scientists now have a better understanding about a site with the most chemically diverse mineral veins NASA's Curiosity rover has examined on Mars, thanks in part to a valuable new resource scientists used in analyzing data from the rover.
Curiosity examined bright and dark mineral veins in March 2015 at a site called "Garden City," where some veins protrude as high as two finger widths above the eroding bedrock in which they formed.

The diverse composition of the crisscrossing veins points to multiple episodes of water moving through fractures in the bedrock when it was buried. During some wet periods, water carried different dissolved substances than during other wet periods. When conditions dried, fluids left clues behind that scientists are now analyzing for insights into how ancient environmental conditions changed over time.



'Garden City' Vein Complex on Lower Mount Sharp, Mars

"These fluids could be from different sources at different times," said Diana Blaney, a Curiosity science team member at NASA's Jet Propulsion Laboratory, Pasadena, California. "We see crosscutting veins with such diverse chemistry at this localized site. This could be the result of distinct fluids migrating through from a distance, carrying chemical signatures from where they'd been."
Researchers used Curiosity's laser-firing Chemistry and Camera (ChemCam) instrument to record the spectra of sparks generated by zapping 17 Garden City targets with the laser. The unusually diverse chemistry detected at Garden City includes calcium sulfate in some veins and magnesium sulfate in others. Additional veins were found to be rich in fluorine or varying levels of iron.

As researchers analyzed Curiosity's observations of the veins, the ChemCam team was completing the most extensive upgrade to its data-analysis toolkit since Curiosity reached Mars in August 2012. They more than tripled -- to about 350 -- the number of Earth-rock geochemical samples examined with a test version of ChemCam. This enabled an improvement in their data interpretation, making it more sensitive to a wider range of possible composition of Martian rocks.

Blaney said, "The chemistry at Garden City would have been very enigmatic if we didn't have this recalibration."



Thick, Dark Veins at 'Garden City,' Mars

The Garden City site is just uphill from a mudstone outcrop called "Pahrump Hills," which Curiosity investigated for about six months after reaching the base of multi-layered Mount Sharp in September 2014. The mission is examining ancient environments that offered favorable conditions for microbial life, if Mars has ever hosted any, and the changes from those environments to drier conditions that have prevailed on Mars for more than 3 billion years. Curiosity has found evidence that base layers of Mount Sharp were deposited in lakes and rivers. The wet conditions recorded by the Garden City veins existed in later eras, after the mud deposited in lakes had hardened into rock and cracked.
Eye-catching geometry revealed in images of the veins offers additional clues. Younger veins continue uninterrupted across intersections with veins that formed earlier, indicating relative ages.

ChemCam provides the capability of making distinct composition readings of multiple laser targets close together on different veins, rather than lumping the information together. The chemistry of these veins is also related to mineral alteration observed at other places on and near Mount Sharp. What researchers learned here can be used to help understand a very complex fluid chemical history in the region. Since leaving Garden City, Curiosity has climbed to higher, younger layers of Mount Sharp.



Dark, Thin Fracture-Filling Material

Today, Blaney presented findings from ChemCam's Garden City investigations at the annual meeting of the American Astronomical Society's Division for Planetary Science, in National Harbor, Maryland.
The U.S. Department of Energy's Los Alamos National Laboratory in Los Alamos, New Mexico, developed ChemCam in partnership with scientists and engineers funded by the French national space agency. More information is available at:

http://www.msl-chemcam.com

NASA's Jet Propulsion Laboratory built Curiosity and manages the project for NASA's Science Mission Directorate in Washington. For more the mission, visit:

http://www.nasa.gov/msl
http://mars.nasa.gov/msl

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Curiosity Rover Will Study Dunes on Route up Mountain
 
This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows a dark sand dune in the middle distance. The rover's examination of dunes on the way toward higher layers of Mount Sharp will be the first in-place study of an active sand dune anywhere other than Earth.

The scene combines several images taken on Sept. 25, 2015, during the 1,115th Martian day, or sol, of Curiosity's work on Mars. The images are from Mastcam's right-eye camera, which has a telephoto lens. The view is toward south-southwest.

The dunes on Curiosity's route are part of a band of dunes called "Bagnold Dunes," along the northwestern edge of Mount Sharp. The informal naming recognizes British military engineer Ralph Bagnold (1896-1990), a pioneer in the study of how winds move sand particles of dunes on Earth. The dune field is evident as a dark band in orbital images of the area inside Gale Crater were Curiosity has been active since landing in 2012, such as a traverse map at http://mars.nasa.gov/multimedia/images/?ImageID=7543.

Dunes are larger than wind-blown ripples of sand or dust that Curiosity and other rovers have visited previously. One dune that Curiosity will investigate in coming days is as tall as a two-story building and as broad as a football field. Ripples on the surface of these Martian dunes are larger than ripples on the surfaces of sand dunes on Earth.

Orbital View of Dune That Curiosity Will Visit
 
This view taken from orbit around Mars shows the sand dune that will be the first to be visited by NASA's Curiosity Mars Rover along its route to higher layers of Mount Sharp.

The view covers an area about 1,250 feet (about 380 meters) across, showing a site called "Dune 1" in the "Bagnold Dunes" dune field. It was taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. The image is in false color, combining information recorded by HiRISE in red, blue-green and infrared frequencies of light.

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On its way to higher layers of the mountain where it is investigating how Mars' environment changed billions of years ago, NASA's Curiosity Mars rover will take advantage of a chance to study some modern Martian activity at mobile sand dunes.

In the next few days, the rover will get its first close-up look at these dark dunes, called the "Bagnold Dunes," which skirt the northwestern flank of Mount Sharp. No Mars rover has previously visited a sand dune, as opposed to smaller sand ripples or drifts. One dune Curiosity will investigate is as tall as a two-story building and as broad as a football field. The Bagnold Dunes are active: Images from orbit indicate some of them are migrating as much as about 3 feet (1 meter) per Earth year. No active dunes have been visited anywhere in the solar system besides Earth.
"We've planned investigations that will not only tell us about modern dune activity on Mars but will also help us interpret the composition of sandstone layers made from dunes that turned into rock long ago," said Bethany Ehlmann of the California Institute of Technology and NASA's Jet Propulsion Laboratory, both in Pasadena, California.

As of Monday, Nov. 16, Curiosity has about 200 yards or meters remaining to drive before reaching "Dune 1." The rover is already monitoring the area's wind direction and speed each day and taking progressively closer images, as part of the dune research campaign. At the dune, it will use its scoop to collect samples for the rover's internal laboratory instruments, and it will use a wheel to scuff into the dune for comparison of the surface to the interior.

Curiosity has driven about 1,033 feet (315 meters) in the past three weeks, since departing an area where its drill sampled two rock targets just 18 days apart. The latest drilled sample, "Greenhorn," is the ninth since Curiosity landed in 2012 and sixth since reaching Mount Sharp last year. The mission is studying how Mars' ancient environment changed from wet conditions favorable for microbial life to harsher, drier conditions.

Before Curiosity's landing, scientists used images from orbit to map the landing region's terrain types in a grid of 140 square quadrants, each about 0.9 mile (1.5 kilometers) wide. Curiosity entered its eighth quadrant this month. It departed one called Arlee, after a geological district in Montana, and drove into one called Windhoek, for a geological district in Namibia. Throughout the mission, the rover team has informally named Martian rocks, hills and other features for locations in the quadrant's namesake area on Earth. There's a new twist for the Windhoek Quadrant: scientists at the Geological Society of Namibia and at the Gobabeb Research and Training Center in Namibia have provided the rover team with a list of Namibian geological place names to use for features in this quadrant. The Windhoek theme was chosen for this sand-dune-bearing quadrant because studies of the Namib Desert have aided interpretation of dune and playa environments on Mars.

What distinguishes actual dunes from windblown ripples of sand or dust, like those found at several sites visited previously by Mars rovers, is that dunes form a downwind face steep enough for sand to slide down. The effect of wind on motion of individual particles in dunes has been studied extensively on Earth, a field pioneered by British military engineer Ralph Bagnold (1896-1990). Curiosity's campaign at the Martian dune field informally named for him will be the first in-place study of dune activity on a planet with lower gravity and less atmosphere.

Observations of the Bagnold Dunes with the Compact Reconnaissance Imaging Spectrometer on NASA's Mars Reconnaissance Orbiter indicate that mineral composition is not evenly distributed in the dunes. The same orbiter's High Resolution Imaging Science Experiment has documented movement of Bagnold Dunes.

"We will use Curiosity to learn whether the wind is actually sorting the minerals in the dunes by how the wind transports particles of different grain size," Ehlmann said.

As an example, the dunes contain olivine, a mineral in dark volcanic rock that is one of the first altered into other minerals by water. If the Bagnold campaign finds that other mineral grains are sorted away from heavier olivine-rich grains by the wind's effects on dune sands, that could help researchers evaluate to what extent low and high amounts of olivine in some ancient sandstones could be caused by wind-sorting rather than differences in alteration by water.

Ehlmann and Nathan Bridges of the Johns Hopkins University's Applied Physics Laboratory, Laurel, Maryland, lead the Curiosity team's planning for the dune campaign.
"These dunes have a different texture from dunes on Earth," Bridges said. "The ripples on them are much larger than ripples on top of dunes on Earth, and we don't know why. We have models based on the lower air pressure. It takes a higher wind speed to get a particle moving. But now we'll have the first opportunity to make detailed observations."

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http://mars.jpl.nasa.gov/msl/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1876

Fast Facts: -- Curiosity is using its wheels, as well as its science payload, to investigate sand that forms active dunes on Mars.
 -- Plans call for the rover to scoop up and sieve sand for onboard laboratory analysis.

NASA's Curiosity Mars rover has begun an up-close investigation of dark sand dunes up to two stories tall. The dunes are on the rover's trek up the lower portion of a layered Martian mountain.

A view of the rippled surface of what's been informally named "High Dune" is online at:
http://mars.nasa.gov/multimedia/images/?ImageID=7581

A wheel track exposing material beneath the surface of a sand sheet nearby is at:
http://mars.nasa.gov/multimedia/images/?ImageID=7582

The dunes close to Curiosity's current location are part of "Bagnold Dunes," a band along the northwestern flank of Mount Sharp inside Gale Crater. Observations of this dune field from orbit show that edges of individual dunes move as much as 3 feet (1 meter) per Earth year.

The rover's planned investigations include scooping a sample of the dune material for analysis with laboratory instruments inside Curiosity.

Curiosity has been working on Mars since early August 2012. It reached the base of Mount Sharp in 2014 after fruitfully investigating outcrops closer to its landing site and then trekking to the mountain. The main mission objective now is to examine successively higher layers of Mount Sharp.

For more information about Curiosity, visit:
http://mars.nasa.gov/msl

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'Marias Pass,' Contact Zone of Two Martian Rock Units
This May 22, 2015, view from the Mast Camera (Mastcam) in NASA's Curiosity Mars rover shows the "Marias Pass" area where a lower and older geological unit of mudstone -- the pale zone in the center of the image -- lies in contact with an overlying geological unit of sandstone.

12.17.2015
Rocks Rich in Silica Present Puzzles for Mars Rover Team

In detective stories, as the plot thickens, an unexpected clue often delivers more questions than answers. In this case, the scene is a mountain on Mars. The clue: the chemical compound silica. Lots of silica. The sleuths: a savvy band of Earthbound researchers whose agent on Mars is NASA's laser-flashing, one-armed mobile laboratory, Curiosity.
NASA's Curiosity rover has found much higher concentrations of silica at some sites it has investigated in the past seven months than anywhere else it has visited since landing on Mars 40 months ago. Silica makes up nine-tenths of the composition of some of the rocks. It is a rock-forming chemical combining the elements silicon and oxygen, commonly seen on Earth as quartz, but also in many other minerals.

"These high-silica compositions are a puzzle. You can boost the concentration of silica either by leaching away other ingredients while leaving the silica behind, or by bringing in silica from somewhere else," said Albert Yen, a Curiosity science team member at NASA's Jet Propulsion Laboratory, Pasadena, California. "Either of those processes involve water. If we can determine which happened, we'll learn more about other conditions in those ancient wet environments."

Water that is acidic would tend to carry other ingredients away and leave silica behind. Alkaline or neutral water could bring in dissolved silica that would be deposited from the solution. Apart from presenting a puzzle about the history of the region where Curiosity is working, the recent findings on Mount Sharp have intriguing threads linked to what an earlier NASA rover, Spirit, found halfway around Mars. There, signs of sulfuric acidity were observed, but Curiosity's science team is still considering both scenarios -- and others -- to explain the findings on Mount Sharp.

'Big Sky' and 'Greenhorn' Drilling Area on Mount Sharp
This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover covers an area in "Bridger Basin" that includes the locations where the rover drilled a target called "Big Sky" on the mission's Sol 1119 (Sept. 29, 2015) and a target called "Greenhorn" on Sol 1137 (Oct. 18, 2015).
The scene combines portions of several observations taken from sols 1112 to 1126 (Sept. 22 to Oct. 6, 2015) while Curiosity was stationed at Big Sky drilling site. The Big Sky drill hole is visible in the lower part of the scene. The Greenhorn target, in a pale fracture zone near the center of the image, had not yet been drilled when the component images were taken. Researchers selected this pair of drilling sites to investigate the nature of silica enrichment in the fracture zones of the area.

Adding to the puzzle, some silica at one rock Curiosity drilled, called "Buckskin," is in a mineral named tridymite, rare on Earth and never seen before on Mars. The usual origin of tridymite on Earth involves high temperatures in igneous or metamorphic rocks, but the finely layered sedimentary rocks examined by Curiosity have been interpreted as lakebed deposits. Furthermore, tridymite is found in volcanic deposits with high silica content. Rocks on Mars' surface generally have less silica, like basalts in Hawaii, though some silica-rich (silicic) rocks have been found by Mars rovers and orbiters. Magma, the molten source material of volcanoes, can evolve on Earth to become silicic. Tridymite found at Buckskin may be evidence for magmatic evolution on Mars.
Curiosity has been studying geological layers of Mount Sharp, going uphill, since 2014, after two years of productive work on the plains surrounding the mountain. The mission delivered evidence in its first year that lakes in the area billions of years ago offered favorable conditions for life, if microbes ever lived on Mars. As Curiosity reaches successively younger layers up Mount Sharp's slopes, the mission is investigating how ancient environmental conditions evolved from lakes, rivers and deltas to the harsh aridity of today's Mars.

Seven months ago, Curiosity approached "Marias Pass," where two geological layers are exposed in contact with each other. The rover's laser-firing instrument for examining compositions from a distance, Chemistry and Camera (ChemCam), detected bountiful silica in some targets the rover passed on its way to the contact zone. The rover's Dynamic Albedo of Neutrons instrument simultaneously detected that the rock composition was unique in this area.

This map shows the route on lower Mount Sharp that NASA's Curiosity followed between April 19, 2015, and Nov. 5, 2015. During this period the mission investigated silica-rich rock targets including "Buckskin," in the "Maria Pass" area, and "Greenhorn," in the "Bridger Basin" area.
High-silica sites were identified both in the Murray formation -- the lowest and oldest geological unit the rover has visited on Mount Sharp -- and in the overlying Stimson geological unit, which is visible in sandstone ridges within this study area.

"The high silica was a surprise -- so interesting that we backtracked to investigate it with more of Curiosity's instruments," said Jens Frydenvang of Los Alamos National Laboratory in New Mexico and the University of Copenhagen, Denmark.
Gathering clues about silica was a major emphasis in rover operations over a span of four months and a distance of about one-third of a mile (half a kilometer).

The investigations included many more readings from ChemCam, plus elemental composition measurements by the Alpha Particle X-ray Spectrometer (APXS) on the rover's arm and mineral identification of rock-powder samples by the Chemistry and Mineralogy (CheMin) instrument inside the rover.

Buckskin was the first of three rocks where drilled samples were collected during that period. The CheMin identification of tridymite prompted the team to look at possible explanations: "We could solve this by determining whether trydymite in the sediment comes from a volcanic source or has another origin," said Liz Rampe, of Aerodyne Industries at NASA's Johnson Space Center, Houston. "A lot of us are in our labs trying to see if there's a way to make tridymite without such a high temperature."

Beyond Marias Pass, ChemCam and APXS found a pattern of high silica in pale zones along fractures in the bedrock, linking the silica enrichment there to alteration by fluids that flowed through the fractures and permeated into bedrock. CheMin analyzed drilled material from a target called "Big Sky" in bedrock away from a fracture and from a fracture-zone target called "Greenhorn." Greenhorn indeed has much more silica, but not any in the form of tridymite. Much of it is in the form of noncrystalline opal, which can form in many types of environments, including soils, sediments, hot spring deposits and acid-leached rocks.

This image from the Chemistry and Camera (ChemCam) instrument on NASA's Curiosity Mars rover shows detailed texture of a rock target called "Elk" on Mars' Mount Sharp, revealing laminations that are present in much of the Murray Formation geological unit of lower Mount Sharp.
Researchers also used ChemCam's laser and spectrometers to assess Elk's composition and found it to be rich in silica.
The image covers a patch of rock surface about 2.8 inches (7 centimeters) across. It was taken on May 22, 2015, during the mission's 992nd Martian day, or sol. ChemCam's Remote Micro-Imager camera, on top of Curiosity's mast, captured the image from a distance of about 9 feet (2.75 meters). Annotations in red identify five points on Elk that were hit with ChemCam's laser. Each of the highlighted points is a location where ChemCam fired its laser 30 times to ablate a tiny amount of target material. By analyzing the light emitted from this laser-ablation, researchers can deduce the composition of that point. For some purposes, composition is presented as a combination of the information from multiple points on the same rock. However, using the points individually can track fine-scale variations in targets.

"What we're seeing on Mount Sharp is dramatically different from what we saw in the first two years of the mission," said Curiosity Project Scientist Ashwin Vasavada of JPL. "There's so much variability within relatively short distances. The silica is one indicator of how the chemistry changed. It's such a multifaceted and curious discovery, we're going to take a while figuring it out."

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01.04.2016
 
Slip face on Downwind Side of 'Namib' Sand Dune on Mars (Labeled)

This view from NASA's Curiosity Mars Rover shows the downwind side of "Namib Dune," which stands about 13 feet (4 meters) high. The site is part of Bagnold Dunes, a band of dark sand dunes along the northwestern flank of Mars' Mount Sharp.

The component images stitched together into this scene were taken with Curiosity's Navigation Camera (Navcam) on Dec. 17, 2015, during the 1,196th Martian day, or sol, of the rover's work on Mars. In late 2015 and early 2016, Curiosity is conducting the first up-close studies ever made of active sand dunes anywhere but on Earth. Under the influence of Martian wind, the Bagnold Dunes are migrating up to about one yard or meter per Earth year. The view spans from westward on the left to east-southeastward on the right. It is presented as a cylindrical perspective projection.

The downwind, or lee, side of the dunes displays textures quite different from those seen on other surfaces of the dunes. Compare this scene, for example, to a windward surface of nearby "High Dune" (at http://mars.nasa.gov/multimedia/images/?ImageID=7581) from three weeks earlier. As on Earth, the downwind side of a sand dune has a steep slope called a slip face. Sand grains blowing across the windward side of a dune become sheltered from the wind by the dune itself. The sand falls out of the air and builds up on the lee slope until it becomes steepened and flows in mini-avalanches down the face.

This image provides annotations identifying several key features at the downwind side of Namib Dune. From left to right:

-- Horn: where sand is escaping from the dune's lee slope and moving downwind. The ripples overlying the bedrock indicate the escape of the sand.

-- Toe: the downwind extent of the dune.

-- Brink: the transition from the windward (stoss) side of the dune to the downwind (lee) side. The brink is marked by a change in slope from the shallow slopes of the dune crest to the steep slopes of the lee side.

-- Grain Fall: smooth areas that indicate grains bouncing over the brink and coming to rest.

-- Ripples: small ripples that form as sand bounces sideways across the face of the lee slope. Ripples have formed over earlier grain flows that likely occurred when winds were stronger and blowing more directly over the brink of the dune.

-- Grain Flow: tongue-shaped feature caused by sand avalanching down the lee slope of the dune. When sand builds up near the brink of the dune and becomes overly steepened, it flows down the slope. The source area of this flow is also noted. Grain flows are the primary way the dune moves forward over time. Ripples have not yet formed on this surface, suggesting that the flow is recent.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington. JPL designed and built the project's Curiosity rover and its Navcam. For more information about Curiosity, visit http://www.nasa.gov/msl and http://mars.nasa.gov/msl.

Image Credit: NASA/JPL-Caltech
 

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At its current location for inspecting an active sand dune, NASA's Curiosity Mars rover is adding some sample-processing moves not previously used on Mars.
Sand from the second and third samples the rover is scooping from "Namib Dune" will be sorted by grain size with two sieves. The coarser sieve is making its debut, and using it also changes the way the treated sample is dropped into an inlet port for laboratory analysis inside the rover.

Positioning of the rover to grab a bite of the dune posed a challenge, too. Curiosity reached this sampling site, called "Gobabeb," on Jan. 12.
"It was pretty challenging to drive into the sloping sand and then turn on the sand into the position that was the best to study the dunes," said Michael McHenry of NASA's Jet Propulsion Laboratory, Pasadena, California. He is the Curiosity mission's campaign rover planner for collecting these samples.

Curiosity has scooped up sample material at only one other site since it landed on Mars in August 2012. It sampled dust and sand at a windblown drift site called "Rocknest" in October and November 2012. Between there and Gobabeb, the rover collected sample material for analysis at nine rock targets, by drilling rather than scooping.

The mission's current work is the first close-up study of active sand dunes anywhere other than Earth. Namib and nearby mounds of dark sand are part of the "Bagnold Dune Field," which lines the northwestern flank of a layered mountain where Curiosity is examining rock records of ancient environmental conditions on Mars. Investigation of the dunes is providing information about how wind moves and sorts sand particles in conditions with much less atmosphere and less gravity than on Earth.

Sand in dunes has a range of grain sizes and compositions. Sorting by wind will concentrate certain grain sizes and compositions, because composition is related to density, based on where and when the wind has been active. The Gobabeb site was chosen to include recently formed ripples. Information about these aspects of Mars' modern environment may also aid the mission's interpretation of composition variations and ripple patterns in ancient sandstones that formed from wind or flowing water.

Curiosity scooped its first dune sample on Jan. 14, but the rover probed the dune first by scuffing it with a wheel. "The scuff helped give us confidence we have enough sand where we're scooping that the path of the scoop won't hit the ground under the sand," McHenry said.

That first scoop was processed much as Rocknest samples were: A set of complex moves of a multi-chambered device on the rover's arm passed the material through a sieve that screened out particles bigger than 150 microns (0.006 inch); some of the material that passed the sieve was dropped into laboratory inlet ports from a "portioner" on the device; material blocked by the sieve was dumped onto the ground.

The portioner is positioned directly over an opened inlet port on the deck of the rover to drop a portion into it when the processing device is vibrating and a release door is opened. Besides analyzing samples delivered to its internal laboratory instruments, Curiosity can use other instruments to examine sample material dumped onto the ground.

Curiosity collected its second scoop of Gobabeb on Jan. 19. This is when the coarser sieve came into play. It allows particles up to 1 millimeter (1,000 microns or 0.04 inch) to pass through.

Sand from the second scoop was initially fed to the 150-micron sieve. Material that did not pass through that sieve was then fed to the 1-millimeter sieve. The fraction routed for laboratory analysis is sand grains that did not pass through the finer sieve, but did pass through the coarser one.

"What you have left is predominantly grains that are smaller than 1 millimeter and larger than 150 microns," said JPL's John Michael Morookian, rover planning team lead for Curiosity.

This fraction is dropped into a laboratory inlet by the scoop, rather than the portioner. Morookian decribed this step: "We start the vibration and gradually tilt the scoop. The material flows off the end of the scoop, in more of a stream than all at once."

Curiosity reached the base of Mount Sharp in 2014 after fruitfully investigating outcrops closer to its landing site and then trekking to the layered mountain. On the lower portion of the mountain, the mission is studying how Mars' ancient environment changed from wet conditions favorable for microbial life to harsher, drier conditions. For more information about Curiosity, visit:

http://mars.nasa.gov/msl

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Our intrepid rover does a lot of drilling and sampling of the tailings... a great video to explain how this works...

<a href="https://www.youtube.com/v/Qa2sc6-u59I" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">https://www.youtube.com/v/Qa2sc6-u59I</a>

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Wind erosion on Mars...

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<a href="https://www.youtube.com/v/wPOCcG33mJQ" target="_blank" rel="noopener noreferrer" class="bbc_link bbc_flash_disabled new_win">https://www.youtube.com/v/wPOCcG33mJQ</a>

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http://mars.jpl.nasa.gov/msl/news/whatsnew/index.cfm?FuseAction=ShowNews&NewsID=1906

04.27.2016
Curiosity Mars Rover Crosses Rugged Plateau


http://mars.nasa.gov/multimedia/images/?ImageID=7810

NASA's Curiosity Mars rover has nearly finished crossing a stretch of the most rugged and difficult-to-navigate terrain encountered during the mission's 44 months on Mars.
The rover climbed onto the "Naukluft Plateau" of lower Mount Sharp in early March after spending several weeks investigating sand dunes. The plateau's sandstone bedrock has been carved by eons of wind erosion into ridges and knobs. The path of about a quarter mile (400 meters) westward across it is taking Curiosity toward smoother surfaces leading to geological layers of scientific interest farther uphill.

The roughness of the terrain on the plateau raised concern that driving on it could be especially damaging to Curiosity's wheels, as was terrain Curiosity crossed before reaching the base of Mount Sharp. Holes and tears in the rover's aluminum wheels became noticeable in 2013. The rover team responded by adjusting the long-term traverse route, revising how local terrain is assessed and refining how drives are planned. Extensive Earth-based testing provided insight into wheel longevity.

Routine Inspection of Rover Wheel Wear and Tear


The rover team closely monitors wear and tear on Curiosity's six wheels. "We carefully inspect and trend the condition of the wheels," said Steve Lee, Curiosity's deputy project manager at NASA's Jet Propulsion Laboratory, Pasadena, California. "Cracks and punctures have been gradually accumulating at the pace we anticipated, based on testing we performed at JPL. Given our longevity projections, I am confident these wheels will get us to the destinations on Mount Sharp that have been in our plans since before landing."
Inspection of the wheels after crossing most of the Naukluft Plateau has indicated that, while the terrain presented challenges for navigation, driving across it did not accelerate damage to the wheels.

On Naukluft Plateau, the rover's Mast Camera has recorded some panoramic scenes from the highest viewpoints Curiosity has reached since its August 2012 landing on the floor of Gale Crater on Mars. Examples are available online at these sites:

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20332
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20333

The scenes show wind-sculpted textures in the sandstone bedrock close to the rover, and Gale Crater's rim rising above the crater floor in the distance. Mount Sharp stands in the middle of the crater, which is about 96 miles (154 kilometers) in diameter.

The next part of the rover's route will return to a type of lake-deposited mudstone surface examined previously. Farther ahead on lower Mount Sharp are three geological units that have been key destinations for the mission since its landing site was selected. One of the units contains an iron-oxide mineral called hematite, which was detected from orbit. Just above it lies a band rich in clay minerals, then a series of layers that contain sulfur-bearing minerals called sulfates. By examining them with Curiosity, researchers hope to gain a better understanding of how long ancient environmental conditions remained favorable for microbial life, if it was ever present on Mars, before conditions became drier and less favorable.

Each of Curiosity's six wheels is about 20 inches (50 centimeters) in diameter and 16 inches (40 centimeters) wide, milled out of solid aluminum. Most of the wheel's circumference is a metallic skin that is about half the thickness of a U.S. dime. Nineteen zigzag-shaped treads, called grousers, extend about a quarter inch (three-fourths of a centimeter) outward from the skin of each wheel. The grousers bear much of the rover's weight and provide most of the traction and ability to traverse over uneven terrain.

The holes seen in the wheels so far perforate only the skin. Wheel-monitoring images obtained every 547 yards (500 meters) have not yet shown any grouser breaks on Curiosity. Earth-based testing examined long-term wear characteristics and the amount of damage a rover wheel can sustain before losing its usefulness for driving. The tests indicate that when three grousers on a wheel have broken, that wheel has reached about 60 percent of its useful mileage.

At a current odometry of 7.9 miles (12.7 kilometers) since its August 2012 landing, Curiosity's wheels are projected to have more than enough life remaining to investigate the hematite, clay and sulfate units ahead, even in the unlikely case that up to three grousers break soon. The driving distance to the start of the sulfate-rich layers is roughly 4.7 miles (7.5 kilometers) from the rover's current location.

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