Category Archives: Mars Rovers

The Landscape of Vera Rubin Ridge

A nice look at the landscape of Vera Rubin Ridge from the Curiosity rover on Mars. I was admiring the stratification. Then I noticed the scale – click the image for a larger view and see the scale on the lower right.

NASA – This view of “Vera Rubin Ridge” from the Chemistry and Camera (ChemCam) instrument on NASA’s Curiosity Mars rover shows multiple sedimentary layers and fracture-filling deposits of minerals.

Buried layers of what is now a ridge became fractured, and the fractures were filled with mineral deposits precipitated from underground fluids that moved through the fractures.

ChemCam’s telescopic Remote Micro-Imager took the 10 component images of this mosaic on July 3, 2017, during the 1,745th Martian day, or sol, of Curiosity’s work on Mars.  The camera was about 377 feet (115 meters) away from the pictured portion of the ridge.  The rover’s location at the time, shown in a Sol 1741 traverse map, was west of the place where it began its ascent up the ridge about two months later.

The scale bar at lower right indicates how wide a feature 9 inches (22.8 centimeters) in width would look in the middle portion of the scene.

ChemCam is one of 10 instruments in Curiosity’s science payload. 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 (CNES), the University of Toulouse and the French national research agency (CNRS). More information about ChemCam is available at http://www.msl-chemcam.com/.

Credit: NASA/JPL-Caltech/CNES/CNRS/LANL/IRAP/IAS/LPGN/Tony Greicius

Vera Rubin Ridge

NASA – This view of “Vera Rubin Ridge” from the Chemistry and Camera (ChemCam) instrument on NASA’s Curiosity Mars rover shows multiple sedimentary layers and fracture-filling deposits of minerals.

Buried layers of what is now a ridge became fractured, and the fractures were filled with mineral deposits precipitated from underground fluids that moved through the fractures.

ChemCam’s telescopic Remote Micro-Imager took the 10 component images of this mosaic on July 3, 2017, during the 1,745th Martian day, or sol, of Curiosity’s work on Mars. The camera was about 377 feet (115 meters) away from the pictured portion of the ridge. The rover’s location at the time, shown in a Sol 1741 traverse map, was west of the place where it began its ascent up the ridge about two months later.

The scale bar at lower right indicates how wide a feature 9 inches (22.8 centimeters) in width would look in the middle portion of the scene.

Image: NASA/JPL-Caltech/CNES/CNRS/LANL/IRAP/IAS/LPGN

Curiosity Climbing Mt Sharp

As seen from orbit (look at the center of the image). Click for a larger view.

NASA – the feature that appears bright blue at the center of this scene is NASA’s Curiosity Mars rover on the northwestern flank of Mount Sharp, viewed by NASA’s Mars Reconnaissance Orbiter.  Curiosity is approximately 10 feet long and 9 feet wide (3.0 meters by 2.8 meters).

The view is a cutout from observation ESP_050897_1750 taken by the High Resolution Imaging Science Experiment (HiRISE) camera on the orbiter on June 5, 2017.  HiRISE has been imaging Curiosity about every three months, to monitor the surrounding features for changes such as dune migration or erosion.

When the image was taken, Curiosity was partway between its investigation of active sand dunes lower on Mount Sharp, and “Vera Rubin Ridge,” a destination uphill where the rover team intends to examine outcrops where hematite has been identified from Mars orbit.  The rover’s surroundings include tan rocks and patches of dark sand. The rover’s location that day is shown at https://mars.nasa.gov/multimedia/images/2017/curiositys-traverse-map-through-sol-1717 as the point labeled 1717. Images taken by Curiosity’s Mast Camera (Mastcam) at that location are at https://mars.nasa.gov/msl/multimedia/raw/?s=1717&camera=MAST%5F.

As in previous HiRISE color images of Curiosity since the rover was at its landing site, the rover appears bluer than it really is. HiRISE color observations are recorded in a red band, a blue-green band and an infrared band, and displayed in red, green and blue.  This helps make differences in Mars surface materials apparent, but does not show natural color as seen by the human eye.

Lower Mount Sharp was chosen as a destination for the Curiosity mission because the layers of the mountain offer exposures of rocks that record environmental conditions from different times in the early history of the Red Planet. Curiosity has found evidence for ancient wet environments that offered conditions favorable for microbial life, if Mars has ever hosted life.

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colorado. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project and Mars Science Laboratory Project for NASA’s Science Mission Directorate, Washington.

Image Credit: NASA/JPL-Caltech/Univ. of Arizona

Curiosity’s Traction Control

Readers who’ve been around for a while know we’ve been keeping an eye on Curiosity’s wheels; they have taken a beating traveling around on Mars.

NASA of course has been working the problem right from the beginning and they now have come up with an algorithm to help with the problem.

JPL/NASA (Andrew Good) – There are no mechanics on Mars, so the next best thing for NASA’s Curiosity rover is careful driving.

A new algorithm is helping the rover do just that. The software, referred to as traction control, adjusts the speed of Curiosity’s wheels depending on the rocks it’s climbing. After 18 months of testing at NASA’s Jet Propulsion Laboratory in Pasadena, California, the software was uploaded to the rover on Mars in March. Mars Science Laboratory’s mission management approved it for use on June 8, after extensive testing at JPL and multiple tests on Mars.

Even before 2013, when the wheels began to show signs of wear, JPL engineers had been studying how to reduce the effects of the rugged Martian surface. On level ground, all of the rover’s wheels turn at the same speed. But when a wheel goes over uneven terrain, the incline causes the wheels behind or in front of it to start slipping.

This change in traction is especially problematic when going over pointed, embedded rocks. When this happens, the wheels in front pull the trailing wheels into rocks; the wheels behind push the leading wheels into rocks.

In either case, the climbing wheel can end up experiencing higher forces, leading to cracks and punctures. The treads on each of Curiosity’s six wheels, called grousers, are designed for climbing rocks. But the spaces between them are more at risk.

“If it’s a pointed rock, it’s more likely to penetrate the skin between the wheel grousers,” said Art Rankin of JPL, the test team lead for the traction control software. “The wheel wear has been cause for concern, and although we estimate they have years of life still in them, we do want to reduce that wear whenever possible to extend the life of the wheels.”

The traction control algorithm uses real-time data to adjust each wheel’s speed, reducing pressure from the rocks. The software measures changes to the suspension system to figure out the contact points of each wheel. Then, it calculates the correct speed to avoid slippage, improving the rover’s traction.

During testing at JPL, the wheels were driven over a six-inch (15-centimeter) force torque sensor on flat terrain. Leading wheels experienced a 20 percent load reduction, while middle wheels experienced an 11 percent load reduction, Rankin said.

Traction control also addresses the problem of wheelies. Occasionally, a climbing wheel will keep rising, lifting off the actual surface of a rock until it’s free-spinning. That increases the forces on the wheels that are still in contact with terrain. When the algorithm detects a wheelie, it adjusts the speeds of the other wheels until the rising wheel is back into contact with the ground.

Rankin said that the traction control software is currently on by default, but can be turned off when needed, such as for regularly scheduled wheel imaging, when the team assesses wheel wear.

The software was developed at JPL by Jeff Biesiadecki and Olivier Toupet. JPL, a division of Caltech in Pasadena, manages the Curiosity mission for NASA.

Image: NASA

Curious Travels on Pahrump Hills

I must say I’m a bit surprised at the diversity of minerals in the samples between sites.

 
NASA scientists have found a wide diversity of minerals in the initial samples of rocks collected by the Curiosity rover in the lowermost layers of Mount Sharp on Mars, suggesting that conditions changed in the water environments on the planet over time.

Curiosity landed near Mount Sharp in Gale Crater in August 2012. It reached the base of the mountain in 2014. Layers of rocks at the base of Mount Sharp accumulated as sediment within ancient lakes around 3.5 billion years ago. Orbital infrared spectroscopy had shown that the mountain’s lowermost layers have variations in minerals that suggest changes in the area have occurred.

In a paper published recently in Earth and Planetary Science Letters, scientists in the Astromaterials Research and Exploration Science (ARES) Division at NASA’s Johnson Space Center in Houston report on the first four samples collected from the lower layers of Mount Sharp.

“We went to Gale Crater to investigate these lower layers of Mount Sharp that have these minerals that precipitated from water and suggest different environments,” said Elizabeth Rampe, the first author of the study and a NASA exploration mission scientist at Johnson. “These layers were deposited about 3.5 billion years ago, coinciding with a time on Earth when life was beginning to take hold. We think early Mars may have been similar to early Earth, and so these environments might have been habitable.”

The minerals found in the four samples drilled near the base of Mount Sharp suggest several different environments were present in ancient Gale Crater. There is evidence for waters with different pH and variably oxidizing conditions. The minerals also show that there were multiple source regions for the rocks in “Pahrump Hills” and “Marias Pass.”

The paper primarily reports on three samples from the Pahrump Hills region. This is an outcrop at the base of Mount Sharp that contains sedimentary rocks scientists believe formed in the presence of water. The other sample, called “Buckskin,” was reported last year, but those data are incorporated into the paper.

Studying such rock layers can yield information about Mars’ past habitability, and determining minerals found in the layers of sedimentary rock yields much data about the environment in which they formed. Data collected at Mount Sharp with the Chemistry and Mineralogy (CheMin) instrument on Curiosity showed a wide diversity of minerals.

At the base are minerals from a primitive magma source; they are rich in iron and magnesium, similar to basalts in Hawaii. Moving higher in the section, scientists saw more silica-rich minerals. In the “Telegraph Peak” sample, scientists found minerals similar to quartz. In the “Buckskin” sample, scientists found tridymite. Tridymite is found on Earth, for example, in rocks that formed from partial melting of Earth’s crust or in the continental crust — a strange finding because Mars never had plate tectonics.

In the “Confidence Hills” and “Mojave 2” samples, scientists found clay minerals, which generally form in the presence of liquid water with a near-neutral pH, and therefore could be good indicators of past environments that were conducive to life. The other mineral discovered here was jarosite, a salt that forms in acidic solutions. The jarosite finding indicates that there were acidic fluids at some point in time in this region.

There are different iron-oxide minerals in the samples as well. Hematite was found near the base; only magnetite was found at the top. Hematite contains oxidized iron, whereas magnetite contains both oxidized and reduced forms of iron. The type of iron-oxide mineral present may tell scientists about the oxidation potential of the ancient waters.

The authors discuss two hypotheses to explain this mineralogical diversity. The lake waters themselves at the base were oxidizing, so either there was more oxygen in the atmosphere or other factors encouraged oxidation. Another hypothesis — the one put forward in the paper — is that later-stage fluids arose. After the rock sediments were deposited, some acidic, oxidizing groundwater moved into the area, leading to precipitation of the jarosite and hematite. In this scenario, the environmental conditions present in the lake and in later groundwater were quite different, but both offered liquid water and a chemical diversity that could have been exploited by microbial life.

“We have all this evidence that Mars was once really wet but now is dry and cold,” Rampe said. “Today, much of the water is locked up in the poles and in the ground at high latitudes as ice. We think that the rocks Curiosity has studied reveal ancient environmental changes that occurred as Mars started to lose its atmosphere and water was lost to space.”

In the paper, the authors discuss whether this specific area on Mars is a mark of this event happening or just a natural drying of this area. Scientists will search for answers to these questions as the rover moves up the mountain.

Image: NASA/JPL-Caltech/MSSS

NASA also provided a link to the paper (downloadable PDF)

A Scenario for Gale Crater on Mars

So this brings up the question would have the same oxidation processes interfered with life processes at a critical early state or would have it actually assisted them?   Good work by Stony Brook and NASA.

NASA — This diagram presents some of the processes and clues related to a long-ago lake on Mars that became stratified, with the shallow water richer in oxidants than deeper water was.

The sedimentary rocks deposited within a lake in Mars’ Gale Crater more than three billion years ago differ from each other in a pattern that matches what is seen in lakes on Earth. As sediment-bearing water flows into a lake, bedding thickness and particle size progressively decrease as sediment is deposited in deeper and deeper water as seen in examples of thick beds (PIA19074) from shallowest water, thin beds (PIA19075) from deeper water and even thinner beds (PIA19828) from deepest water.

At sites on lower Mount Sharp, inside the crater, measurements of chemical and mineral composition by NASA’s Curiosity Mars rover reveal a clear correspondence between the physical characteristics of sedimentary rock from different parts of the lake and how strongly oxidized the sediments were. Rocks with textures indicating that the sediments were deposited near the edge of a lake have more strongly oxidized composition than rocks with textures indicating sedimentation in deep water. For example, the iron mineral hematite is more oxidized than the iron mineral magnetite.

An explanation for why such chemical stratification occurs in a lake is that the water closer to the surface is more exposed to oxidizing effects of oxygen in the atmosphere and ultraviolet light.

On Earth, a stratified lake with a distinct boundary between oxidant-rich shallows and oxidant-poor depths provides a diversity of environments suited to different types of microbes. If Mars has ever hosted microbial live, the stratified lake at Gale Crater may have similarly provided a range of different habitats for life.

Image: NASA/JPL-Caltech/Stony Brook University

Martian Halos

REMINDER:  There will be a Space X launch at 21:55 UT / 17:55 ET today!  I will have a live feed up.  Nobody does launch video like Space X.

NASA – Pale zones called “halos” border bedrock fractures visible in this 2015 image from NASA’s Curiosity Mars rover which has been darkened (a previously released image can be seen at PIA20268). Measurements overlaid on the image offer a sense of scale for the size of these fractures. The rover team determined that the halos are rich in silica, a clue to the duration of wet environmental conditions long ago. The location is on the lower slope of Mars’ Mount Sharp.

Curiosity’s Navigation Camera (Navcam) acquired the component images of this mosaic on Aug. 23, 2015, during the 1.083rd Martian day, or sol, of the mission. The location is along the rover’s path between “Marias Pass” and “Bridger Basin.” In this region, the rover has found fracture zones to be associated with rock compositions enriched in silica, relative to surrounding bedrock.

Image:  NASA/JPL-Caltech

Opportunity Update

Yes the Mars Exploration Rover Opportunity is STILL doing good science on the Martian surface since arriving at  Mars on 25 January 2004 – that’s over 13 years ago!  Go Oppy!

The image above is a cropped version of the original (find it here at NASA). The tracks are visible in the lower center of the image.

Here’s the NASA caption:

NASA’s Mars Exploration Rover Opportunity worked for 30 months on a raised segment of Endeavour Crater’s rim called “Cape Tribulation” until departing that segment in mid-April 2017, southbound toward a new destination. This view looks back at the southern end of Cape Tribulation from about two football fields’ distance away. The component images were taken by the rover’s Panoramic Camera (Pancam) on April 21, during the 4,707th Martian day, or sol, of Opportunity’s mission on Mars.

Wheel tracks can be traced back to see the rover’s route as it descended and departed Cape Tribulation. For scale, the distance between the two parallel tracks is about 3.3 feet (1 meter). The rover drove from the foot of Cape Tribulation to the head of “Perseverance Valley” in seven drives totaling about one-fifth of a mile (one-third of a kilometer). An annotated map of the area is at PIA21496. (edit: link goes off site use your back button to return)

The elevation difference between the highest point visible in this scene and the rover’s location when the images were taken is about 180 feet (55 meters).

This view looks northward. It merges exposures taken through three of the Pancam’s color filters, centered on wavelengths of 753 nanometers (near-infrared), 535 nanometers (green) and 432 nanometers (violet). It is presented in approximately true color.

Image Credit:  NASA/JPL-Caltech/Cornell/Arizona State Univ.

 

Sand Dunes on Mars

It has been a while since I’ve done a Curiosity rover update. Curiosity continues to do great science on Mars, although the wheels are showing more wear and hopefully design modifications are in place for the next rover. Still, Curiosity can get around and with judicious planning it will continue to do so in the future.

The image shows there is wind on Mars and that helps keep Curiosity clean enough to provide power for operations and the wind is strong enough to make ripples in the landscape. One would imagine the texture is very fine because the wind is blowing in a thin atmosphere. The primarily Carbon Dioxide atmosphere (95.6 %) on Mars has a pressure only around 0.6 percent of what we see here on Earth.

NASA – This view from the Mast Camera (Mastcam) on NASA’s Curiosity Mars rover shows two scales of ripples, plus other textures, in an area where the mission examined a linear-shaped dune in the Bagnold dune field on lower Mount Sharp.

The scene is an excerpt from a 360-degree panorama acquired on March 24 and March 25, 2017, (PST) during the 1,647th Martian day, or sol, of Curiosity’s work on Mars, at a location called “Ogunquit Beach.”

Crests of the longer ripples visible in the dark sand of the dune are several feet (a few meters) apart. This medium-scale feature in active sand dunes on Mars was one of Curiosity’s findings at the crescent-shaped dunes that the rover examined in late 2015 and early 2016. Ripples that scale are not seen on Earth’s sand dunes. Overlaid on those ripples are much smaller ripples, with crests about ten times closer together.

Textures of the local bedrock in the foreground — part of the Murray formation that originated as lakebed sediments — and of gravel-covered ground (at right) are also visible. The image has been white-balanced so that the colors of the colors of the rock and sand materials resemble how they would appear under daytime lighting conditions on Earth.

Image: NASA/JPL-Caltech/MSSS

Kick Those Tires

We have been following the wheel wear on the Curiosity rover for a few years now.

NASA of course noticed and have been keeping an eye on the wheels with regular inspections.  New breaks in the tread have been found.

Credits: NASA/JPL-Caltech/MSSS

Here’s the latest status report from NASA:

A routine check of the aluminum wheels on NASA’s Curiosity Mars rover has found two small breaks on the rover’s left middle wheel—the latest sign of wear and tear as the rover continues its journey, now approaching the 10-mile (16 kilometer) mark.

The mission’s first and second breaks in raised treads, called grousers, appeared in a March 19 image check of the wheels, documenting that these breaks occurred after the last check, on Jan. 27.

“All six wheels have more than enough working lifespan remaining to get the vehicle to all destinations planned for the mission,” said Curiosity Project Manager Jim Erickson at NASA’s Jet Propulsion Laboratory, Pasadena, California. “While not unexpected, this damage is the first sign that the left middle wheel is nearing a wheel-wear milestone,”

The monitoring of wheel damage on Curiosity, plus a program of wheel-longevity testing on Earth, was initiated after dents and holes in the wheels were seen to be accumulating faster than anticipated in 2013. Testing showed that at the point when three grousers on a wheel have broken, that wheel has reached about 60 percent of its useful life. Curiosity already has driven well over that fraction of the total distance needed for reaching the key regions of scientific interest on Mars’ Mount Sharp.

Curiosity Project Scientist Ashwin Vasavada, also at JPL, said, “This is an expected part of the life cycle of the wheels and at this point does not change our current science plans or diminish our chances of studying key transitions in mineralogy higher on Mount Sharp.”

Curiosity is currently examining sand dunes partway up a geological unit called the Murray formation. Planned destinations ahead include the hematite-containing “Vera Rubin Ridge,” a clay-containing geological unit above that ridge, and a sulfate-containing unit above the clay unit.

The rover is climbing to sequentially higher and younger layers of lower Mount Sharp to investigate how the region’s ancient climate changed billions of years ago. Clues about environmental conditions are recorded in the rock layers. During its first year on Mars, the mission succeeded at its main goal by finding that the region once offered environmental conditions favorable for microbial life, if Mars has ever hosted life. The conditions in long-lived ancient freshwater Martian lake environments included all of the key chemical elements needed for life as we know it, plus a chemical source of energy that is used by many microbes on Earth.

Through March 20, Curiosity has driven 9.9 miles (16.0 kilometers) since the mission’s August 2012 landing on Mars. Studying the transition to the sulfate unit, the farthest-uphill destination, will require about 3.7 miles (6 kilometers) or less of additional driving. For the past four years, rover drive planners have used enhanced methods of mapping potentially hazardous terrains to reduce the pace of damage from sharp, embedded rocks along the rover’s route.

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. The wheels contact ground with a skin that’s about half as thick as a U.S. dime, except at thicker treads. The grousers are 19 zigzag-shaped treads that 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.

JPL, a division of Caltech in Pasadena, California, manages NASA’s Mars Science Laboratory Project for NASA’s Science Mission Directorate, Washington, and built the project’s rover, Curiosity. For more information about the mission, visit: