Determining whether a Martian crater is impact or volcanic

Determining whether a Martian crater is impact or volcanic
Click for original image.

Overview map

Cool image time! The picture above, rotated, cropped, reduced, and sharpened to post here, was taken on March 22, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). The camera team labeled this “Crater rim and ejecta,” which subtly reveals the picture’s scientific purpose.

The white dot on the overview map to the right indicates the location of this 15-mile-wide unnamed crater, about 150 miles northwest of where the rover Opportunity landed and traveled south to the rim of Endeavour Crater. It also shows in the inset that the crater appears to sit in the center of an upraised mound, suggesting it was formed not by impact but by volcanic processes.

This picture however says otherwise. The many small mounds and mesas to the south of the crater rim are not what one would expect on the apron of a volcano. Instead, they suggest this crater is an impact, with those mounds the eroded ejecta from that impact, now also partly buried by dust. This hypothesis is strengthened by the data from Opportunity, which found a great deal of impact ejecta during its travels, possibly from the very event that created this crater.

Data from Opportunity suggests surface dew periodically appears even in the dry equatorial regions

Using data from the rover Opportunity, scientists now think that the renewal of Martian salt crusts on rock surfaces on the rim of Endeavour Crater could possibly by caused by the appearance of rare thin wetting events, and that such events could have even occurred very recently and be on-going..

The scientists looked at the rate of erosion and renewal of the salt crusts, and found them to be in a steady state. The erosion is slow, taking from 200,000 to 2,000,000 years to remove 1 to 2 millimeters. However, periodically a thin film of water or wetting occurs, not unlike dew on Earth, which quickly acts to renew the crust. As David Mittlefehldt of the Astromaterials Research Office at the Johnson Space Center and the lead author of the paper explained to me,

Taken together, the data leaves open the possibility the salt mobilization has occurred within the last few thousand years. It could be ongoing in the sense that over a period of thousands? or hundreds? of years it might happen again.

In other words, the evidence suggests that every few hundred or thousand years the surface of these rocks gets wet, which results in the placement of a new thin layer of salt crusts.

Mittlefehldt also emphasized to me that these wetting events are rare, and “there is also the case that such an event may never come again because of changing conditions.”

The situation is essentially like on Earth, where in some places hydrologists measure the size of floods by how rare they are. A 1,000 year flood is big, but it happens very rarely. At Endeavour Crater these wetting events are comparably rare, but they do not involve big floods, but a mere moistening of the ground.

The location of Endeavour Crater is about 2 degrees south latitude, so it sits in the dry equatorial regions where no surface or near surface ice has so far been found. However, the cyclic nature of Mars’ orbit and obliquity could have changed this in the past, and could change this again in the future. At this time we simply don’t have enough information to know.

Midnight repost: Mars!

The tenth anniversary retrospective of Behind the Black continues: Despite my many essays on culture and politics, Behind the Black remains mostly a site reporting on space and science. Since the modern exploration of Mars is probably the most significant on-going event now in space, it seemed unsatisfactory to only repost one or two of my past articles on this subject, when I have probably have posted hundreds. Instead, this midnight repost will provide links to a bunch, divided into several topics.

Martian geology, shown in cool images

First, we have the many cool images I have posted on Mars, often tied to detailed descriptions of what scientists are now beginning to learn about the red planet’s mysterious geological history. The following are the most important, and will help readers better understand future cool images.

Future colonization

Next, two posts, both focused on the future exploration and colonization of Mars.
» Read more

Opportunity’s parting shot

Opportunity's last panorama
Click for full image.

The Opportunity science team today released the last full 360 degree panorama taken by the rover last spring, prior to the global dust storm that ended its fifteen year mission on Mars.

Over 29 days last spring, NASA’s Mars Exploration Rover Opportunity documented this 360-degree panorama from multiple images taken at what would become its final resting spot in Perseverance Valley. Located on the inner slope of the western rim of Endurance Crater, Perseverance Valley is a system of shallow troughs descending eastward about the length of two football fields from the crest of Endeavor’s rim to its floor.

“This final panorama embodies what made our Opportunity rover such a remarkable mission of exploration and discovery,” said Opportunity project manager John Callas of NASA’s Jet Propulsion Laboratory in Pasadena, California. “To the right of center you can see the rim of Endeavor Crater rising in the distance. Just to the left of that, rover tracks begin their descent from over the horizon and weave their way down to geologic features that our scientists wanted to examine up close. And to the far right and left are the bottom of Perseverance Valley and the floor of Endeavour crater, pristine and unexplored, waiting for visits from future explorers.”

If you click on the image above you can go to the full image and zoom and scan across it.

Rover update: February 20, 2019

Summary: Curiosity in the clay unit valley. Opportunity’s long journey is over. Yutu-2 creeps to the northwest on the Moon’s far side.

For the overall context of Curiosity’s travels, see my March 2016 post, Pinpointing Curiosity’s location in Gale Crater.

For the updates in the past year go here. For a full list of updates before February 8, 2018, go here.

Curiosity

Curiosity's view to the east on Sol 2316
Click image for full resolution version

Overview of Curiosity's future travels
Click image for original image

Since my January 22, 2019 update, Curiosity finally drove down off of Vera Rubin Ridge into a valley between the ridge and the lower slopes of Mt Sharp. The Mars Reconnaissance Orbiter (MRO) overview on the right has been annotated by me to show the rover’s travels (shown by the yellow dotted line), with its proposed route indicated by the red dotted line. The yellow lines indicate approximately the terrain seen in the panorama above. The panorama was created from images taken on Sol 2016.

The valley that Curiosity is presently traversing is dubbed “the clay unit” or “the clay-bearing unit” by the geologists, based on its make-up determined from orbital data. So far they have found this terrain to be “some of the best driving terrain we’ve encountered in Gale Crater, with just some occasional sandy patches in the lee of small ridges.” Initially they had problems finding any rocks or pebbles large enough for the instruments to use for gathering geological data. For the past week or so, however, they have stopped at “bright exposure of rock” where some bedrock was visible, giving them much better material to work with.
» Read more

NASA officially declares Opportunity dead

NASA today officially announced that the rover Opportunity — built to last 90 days — is dead, only three weeks after celebrating its fifteenth anniversary operating on the Martian surface.

This is what project scientist Steve Squyres had to say about the rover’s finish:

“When I saw that the storm had gone global, I thought this could be it,” said Squyres, explaining that Opportunity was a solar-powered vehicle and needed the sun for energy. “To have Opportunity – designed for 90 days – taken out after fourteen and a half years by one of the most ferocious dust storms to hit the planet in decades, you have got to feel pretty good about it.”

He said: “It was an honorable end, and it came a whole lot later than any of us expected.”

The article gives some nice background into the personal stories of many of the scientists who worked on Opportunity for all those years. For some overall scientific context, see this article. Or you can read the many rover updates I have written in the past two and a half years, which will give you a detailed sense of Opportunity’s travels along the rim of Endeavour Crater.

NASA about to pull plug on Opportunity

Rumors today say that during a press conference tomorrow NASA will announce that it is closing the books on the incredibly successful rover Opportunity.

From the first link:

NASA said Tuesday it will issue a final series of recovery commands, on top of more than 1,000 already sent. If there’s no response by Wednesday — which NASA suspects will be the case — Opportunity will be declared dead, 15 years after arriving at the red planet.

Opportunity was supposed to last 90 days. Instead, it lasted just under fifteen years, drove 28 miles, and saw far more of the Martian surface than anyone ever expected.

It now sits inside the rim of fourteen-mile Endeavour Crater, waiting for those first explorers to come and get it. I wonder when that will be.

Planetary rover update: January 22, 2019

Summary: Curiosity begins journey off of Vera Rubin Ridge. Opportunity’s silence is now more than seven months long, with new dust storms arriving. Yutu-2 begins roving the Moon’s far side.

Before providing today’s update, I have decided to provide links to all the updates that have taken place since I provided a full list in my February 8, 2018 update. As I noted then, this allows my new readers to catch up and have a better understanding of where each rover is, where each is heading, and what fascinating things they have seen in the past few years.

These updates began when I decided to figure out the overall context of Curiosity’s travels, which resulted in my March 2016 post, Pinpointing Curiosity’s location in Gale Crater. Then, when Curiosity started to travel through the fascinating and rough Murray Buttes terrain in the summer of 2016, I stated to post regular updates. To understand the press releases from NASA on the rover’s discoveries it is really necessary to understand the larger picture, which is what these updates provide. Soon, I added Opportunity to the updates, with the larger context of its recent travels along the rim of Endeavour Crater explained in my May 15, 2017 rover update.

Now an update of what has happened since November!
» Read more

New local dust storm activity near silent Opportunity

The Opportunity science team reported today that they have noted an increase in local dust storm activity just south of the silent rover.

The storm is expected to increase in opacity (tau) at the rover site to greater than 1.5 over the next few days. No signal from Opportunity has been heard since Sol 5111 (June 10, 2018) during the historic global dust storm. Opportunity likely experienced a low-power fault, a mission clock fault and an up-loss timer fault. Since the loss of signal, the team has been listening for the rover over a broad range of times, frequencies and polarizations using the Deep Space Network (DSN) Radio Science Receiver.

This activity, plus the fact that they have still not been able to re-establish contact with the rover during the recent dust devil season, when they had hoped a devil might clear the dust off the solar panels, bodes very bad for the rover. The Curiosity team is also seeing more dust activity, and notes that these dust storms will also act to reduce the number of dust devils.

Mars rover update: November 8, 2018

Summary: Curiosity finally gets drill samples from the top of Vera Rubin Ridge. Opportunity’s silence now extends to five months.

For a list of past updates beginning in July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's travels on and off Vera Rubin Ridge

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

The traverse map on the right, unchanged from my last rover update on July 17, 2018, shows almost all of Curiosity’s travels on Vera Rubin Ridge. The yellow dotted line is the oldest travel, up onto the ridge and then back down to get a successful drill sample. The green dotted line shows the rover’s return back up onto the top of the ridge, where it attempted and failed to drill into the ridge’s top layer, then experienced a serious computer issue in mid-September that essentially shut down science operations for about five weeks.

With the resumption of science operations about two weeks ago, the rover has moved a short distance on the top of the ridge to a new drill location, where it finally succeeded this week in drilling a hole in the hardest top layer of Vera Rubin Ridge.
» Read more

NASA decides to continue to ping Opportunity

NASA has decided to continue through January its effort to both listen and send signals to Opportunity in the hope of bringing it to life.

The 45-day deadline passed late last week. But NASA will continue active listening — a strategy that involves both sending commands to Opportunity and listening for any peeps the six-wheeled robot may make — for several more months at least, agency officials announced yesterday. “After a review of the progress of the listening campaign, NASA will continue its current strategy for attempting to make contact with the Opportunity rover for the foreseeable future,” NASA officials wrote in a mission update yesterday. “Winds could increase in the next few months at Opportunity’s location on Mars, resulting in dust being blown off the rover’s solar panels,” they added. “The agency will reassess the situation in the January 2019 time frame.”

This is exactly what the planetary scientists wanted. Their hope is that, with the beginning of dust devil season in November, the chances will then increase for removing the dust that likely covers the rover’s solar panels. It is thought that the rover has a better shot at coming back to life during this time period.

Active signaling to Opportunity to end

While NASA will continue to listen for activity from Opportunity for many more months, its active effort to signal the Mars rover is about to end.

After more than a month, Opportunity has not responded to those commands, and that active listening effort will soon end. “We intend to keep pinging Opportunity on a daily basis for at least another week or two,” said Lori Glaze, acting director of NASA’s planetary science division, during a presentation Oct. 22 at the annual meeting of the American Astronomical Society’s Division for Planetary Sciences here.

Glaze said that a factor in ending the active listening campaign is to prepare for the landing of the InSight spacecraft on Mars Nov. 26. “We want to wind that down before InSight gets to Mars and make sure all our orbital assets are focused on a successful landing of InSight,” she said.

That schedule is consistent with previous plans for attempting to restore contact with Opportunity. NASA said Aug. 30 that, once skies cleared sufficiently, it would attempt active listening for 45 days. “If we do not hear back after 45 days, the team will be forced to conclude that the sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover,” John Callas, Opportunity project manager, said in a statement outlining those plans.

I would not be surprised if they do try to signal the rover a few more times, in January after the busy fall period when there are a lot of planetary probes needing access to the Deep Space Network. Even so, it appears the rover’s life is finally at an end, fourteen years past its originally planned lifespan of only 90 days.

Curiosity to switch computers in effort to restore operations

The Curiosity engineering team have decided to switch on-board computers in effort to figure out why the rover has been unable to store and send any data since September 15.

After reviewing several options, JPL engineers recommended that the rover switch from Side B to Side A, the computer the rover used initially after landing.

The rover continues to send limited engineering data stored in short-term memory when it connects to a relay orbiter. It is otherwise healthy and receiving commands. But whatever is preventing Curiosity from storing science data in long-term memory is also preventing the storage of the rover’s event records, a journal of all its actions that engineers need in order to make a diagnosis. The computer swap will allow data and event records to be stored on the Side-A computer.

Side A experienced hardware and software issues over five years ago on sol 200 of the mission, leaving the rover uncommandable and running down its battery. At that time, the team successfully switched to Side B. Engineers have since diagnosed and quarantined the part of Side A’s memory that was affected so that computer is again available to support the mission. [emphasis mine]

As indicated by the highlighted paragraph, the switch does carry some risk. Though they say they have isolated the problems with the A computer, they might be surprised when they turn it on.

Meanwhile, silence continues from Opportunity. After fourteen years of almost continuous rover operations on Mars, the United States have been roverless now for more than two weeks.

Mars Reconnaissance Orbiter spots Opportunity through dust

Mars Reconnaissance Orbiter has taken a picture through the fading Martian dust storm that spots Opportunity about halfway down Perseverance Valley in the rim of Endeavour Crater.

Engineers have been increasing the number of times per day they are attempting to communicate with the rover, so far all to no avail. The picture thus only really tells us that the storm is lifting and that MRO’s high resolution camera is operating normally after three months of limited picture taking because of the dust storm.

NASA resets listening plan for Opportunity

NASA has rearranged its listening plans for the rover Opportunity so that it will extend into the dust devil season beginning in November.

The science team is also sending a command three times a week to elicit a beep if the rover happens to be awake, and will soon be expanding the commanding to include “sweep and beeps” to address a possible complexity with certain conditions within the mission clock fault. These will continue through January of 2019.

The dust storm on Mars continues its decay with atmospheric opacity (tau) over the rover site continuing to decrease. Once the tau has fallen below an estimated measurement of 1.5 twice – with one week apart between measurements – a period of 45 days will begin representing the best time for us to hear from the rover.

This also represents the best time to attempt active commanding during a specific mission clock fault condition. Back during the attempted recovery of the Spirit rover, a technical issue required the team to actively command the rover to communicate. Opportunity has no such issue; if we hear from it, it will likely be from listening passively as we have been, and as we will continue to do through January.

We will also actively attempt to command the rover to communicate during the 45-day listening period to cover the clock fault condition. After that, we will report to NASA on our efforts.

In other words, the final 45 day listening period will not officially begin until the Martian atmosphere has cleared more, rather than begin about now and thus end about the middle of November, before the dust devil season begins.

The reasons they want to listen through the dust devil season is that they believe it likely that the rover’s solar panels have been covered with dust, and will need a nearby dust devil to blow this away. This might sound unlikely, but it has happened several times with both Spirit and Opportunity during both of their spectacularly extended missions.

Some debate at NASA over Opportunity

This story yesterday had the following interesting paragraph:

Members of Opportunity’s engineering team recommended a different plan, the person close to the mission says. Their idea was to actively try to communicate with Opportunity until the end of January 2019 — the end of the seasonal cleaning period. After that, they suggested passive listening until the end of 2019. But these recommendations were ignored by management in order to save money, this person says, meaning the agency could be risking abandoning a still-functioning rover. The Opportunity team reportedly didn’t receive formal notice of the plan until “minutes before JPL published its press release,” according to The Atlantic.

It appears that some on the science team do not feel that the present plan to listen closely for only 45 days, through mid-October, is sufficient, as it will likely require a dust devil to clear Opportunity’s solar panels, and dust devil season will not begin until November.

However, it is very likely wrong to blame the resistance by NASA management to this plan solely to a desire to save money. There are other considerations, such as tying up the Deep Space Network for this one rover when, as I noted yesterday, the October to January time period will be a very very very busy time for that network, with many important new planetary probe events. Seven different spacecraft will either be landing or doing fly-bys on four different solar system targets during that time. Tying the network up to listen for Opportunity will likely not work.

It seems to me that Opportunity should be recovered, if possible, but it also must receive a lower priority during this time period. After New Horizons’ January 1st fly-by of Ultima Thule it might be possible to devote more time then to listening, but I can see the logic, at least in this context, for reducing the listening time from October to January.

Hat tip Kirk Hilliard.

As Mars dust storm clears, Opportunity remains silent

The Opportunity science team today provided a new update on the rover, noting that it remains silent even as the Martian dust storm is clearing.

With skies clearing, mission managers are hopeful the rover will attempt to call home, but they are also prepared for an extended period of silence. “If we do not hear back after 45 days, the team will be forced to conclude that the Sun-blocking dust and the Martian cold have conspired to cause some type of fault from which the rover will more than likely not recover,” said Callas. “At that point our active phase of reaching out to Opportunity will be at an end. However, in the unlikely chance that there is a large amount of dust sitting on the solar arrays that is blocking the Sun’s energy, we will continue passive listening efforts for several months.”

The additional several months for passive listening are an allowance for the possibility that a Red Planet dust devil could come along and literally dust off Opportunity’s solar arrays. Such “cleaning events” were first discovered by Mars rover teams in 2004 when, on several occasions, battery power levels aboard both Spirit and Opportunity increased by several percent during a single Martian night, when the logical expectation was that they would continue to decrease. These cleaning dust devils have even been imaged by both rovers on the surface and spacecraft in orbit (see https://mars.nasa.gov/resources/5307/the-serpent-dust-devil-of-mars/).

It appears however that if nothing is heard from Opportunity by sometime in mid-October, they will be very prepared at that time to begin shutting down ground-based operations here on Earth.

Opportunity’s uncertain future

Link here. This article from JPL provides a detailed status report on the rover, as well as what will happen if they should regain communications.

After the first time engineers hear from Opportunity, there could be a lag of several weeks before a second time. It’s like a patient coming out of a coma: It takes time to fully recover. It may take several communication sessions before engineers have enough information to take action.

The first thing to do is learn more about the state of the rover. Opportunity’s team will ask for a history of the rover’s battery and solar cells and take its temperature. If the clock lost track of time, it will be reset. The rover would take pictures of itself to see whether dust might be caked on sensitive parts, and test actuators to see if dust slipped inside, affecting its joints.

Once they’ve gathered all this data, the team would take a poll about whether they’re ready to attempt a full recovery.

Even if engineers hear back from Opportunity, there’s a real possibility the rover won’t be the same. The rover’s batteries could have discharged so much power — and stayed inactive so long — that their capacity is reduced. If those batteries can’t hold as much charge, it could affect the rover’s continued operations. It could also mean that energy-draining behavior, like running its heaters during winter, could cause the batteries to brown out.

They remain hopeful, but this article is clearly meant to prepare the public for the possibility that Opportunity’s long journey on Mars might have finally ended.

Mars dust storm blocks Mars Reconnaissance Orbiter images

In my normal routine to check out the periodic posting of new high resolution images from Mars Reconnaissance Orbiter (MRO), the August 1 update brought what at first was a disturbing surprise. If you go to the link you will see that a large majority of the images show nothing by a series of vertical lines, as if the high resolution camera on MRO has failed.

Yet, scattered among the images were perfectly sharp images. I started to look at these images to try to figure out the differences, and quickly found that the sharp images were always of features in high latitudes, while the blurred images were closer to the equator.

The August 1 image release covered the June/July time period, when the on-going Martian dust storm was at its height. The images illustrate also where the storm was most opaque, closer to the equator.

The next few updates, which occur every three weeks or so, should show increasing clarity as the storm subsides. And the storm is subsiding, according to the latest Opportunity update. The scientists have still not re-established contact with the rover, and do not expect to for at least a month or more, but they are finding that the atmospheric opacity at Endeavour Crater seems to be dropping.

Mars rover update: July 17, 2018

Summary: Curiosity climbs back up onto Vera Rubin Ridge to attempt its second drillhole since drill recovery, this time at a spot on the ridge with the highest orbital signature for hematite. Opportunity remains silent, shut down due to the global dust storm.

For a list of past updates beginning in July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's travels on and off Vera Rubin Ridge

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

In the almost two months since my May 23, 2018 update, a lot has happened, much of which I covered in daily updates. Curiosity found a good drill spot to once again test the new drilling techniques designed by engineers to bypass its stuck drill feed mechanism, and was successful in getting its first drill sample in about a year and a half. The rover then returned uphill, returning to a spot on Vera Rubin Ridge that, according to satellite data, has the highest signature for hematite on the entire ridge. The light green dotted line in the traverse map to the right shows the route Curiosity has taken back up onto Vera Rubin Ridge. The red dotted line shows the original planned route off the ridge and up Mount Sharp.
» Read more

Martian dust storm goes global

Data from orbit and from Curiosity at Gale Crater confirms that the dust storm that has shut down Opportunity is now a global storm, encircling Mars.

The Martian dust storm has grown in size and is now officially a “planet-encircling” (or “global”) dust event.

Though Curiosity is on the other side of Mars from Opportunity, dust has steadily increased over it, more than doubling over the weekend. The sunlight-blocking haze, called “tau,” is now above 8.0 at Gale Crater — the highest tau the mission has ever recorded. Tau was last measured near 11 over Opportunity, thick enough that accurate measurements are no longer possible for Mars’ oldest active rover.

This will be first global storm to occur on Mars since Curiosity landed in 2012, thus giving scientists the best opportunity to study such an event.

Meanwhile, Opportunity remains silent. This does not mean it is dead, but that it doesn’t have enough sunlight to charge its batteries. It might die during this storm if the storm lasts long enough, but we won’t know one way or the other until the storm finally eases.

Contact with Opportunity lost

The Opportunity science team has lost contact with Opportunity as it automatically shuts down operations to survive low battery power due to the dust storm.

This does not necessarily mean the rover is dead. Depending on how long this period of low power lasts, the rover could return to life once the dust storm passes. Or not. We can only wait and see.

A press conference today on the dust storm and Opportunity’s status begins at 1:30 Eastern time today.

Growing Martian dust storm forces Opportunity to suspend operations

A growing Martian dust storm has forced the Opportunity science team to suspend science operations and to reconfigure the rover’s operations to increase its chances of surviving the storm.

In a matter of days, the storm had ballooned. It now spans more than 7 million square miles (18 million square kilometers) — an area greater than North America — and includes Opportunity’s current location at Perseverance Valley. More importantly, the swirling dust has raised the atmospheric opacity, or “tau,” in the valley in the past few days. This is comparable to an extremely smoggy day that blots out sunlight. The rover uses solar panels to provide power and to recharge its batteries.

Opportunity’s power levels had dropped significantly by Wednesday, June 6, requiring the rover to shift to minimal operations.

This isn’t Opportunity’s first time hunkering down in bad weather: in 2007, a much larger storm covered the planet. That led to two weeks of minimal operations, including several days with no contact from the rover to save power. The project’s management prepared for the possibility that Opportunity couldn’t balance low levels of power with its energy-intensive survival heaters, which protect its batteries from Mars’ extreme cold. It’s not unlike running a car in the winter so that the cold doesn’t sap its battery charge.There is a risk to the rover if the storm persists for too long and Opportunity gets too cold while waiting for the skies to clear.

In other words, there is a possibility that the rover might not make it through this period of low sunlight. Nonetheless, the rover did send four images down yesterday, though the four images are essentially dust filled, and are likely aimed at the far distance to help gauge the extent of the storm.

Mars rover update: May 23, 2018

Summary: Curiosity drives down off of Vera Rubin Ridge to do drilling in lower Murray Formation geology unit, while Opportunity continues to puzzle over the formation process that created Perseverance Valley in the rim of Endeavour Crater.

For a list of past updates beginning in July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's travels on and off Vera Rubin Ridge

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

Since my April 27, 2018 update, Curiosity has continued its downward trek off of Vera Rubin Ridge back in the direction from which it came. The annotated traverse map to the right, cropped and taken from the rover’s most recent full traverse map, shows the rover’s recent circuitous route with the yellow dotted line. The red dotted line shows the originally planned route off of Vera Rubin Ridge, which they have presently bypassed.

It appears they have had several reasons for returning to the Murray Formation below the Hematite Unit on Vera Rubin Ridge. First, it appears they wanted to get more data about the geological layers just below the Hematite Unit, including the layer immediately below, dubbed the Blunts Point member.

While this is certainly their main goal, I also suspect that they wanted to find a good and relatively easy drilling candidate to test their new drill technique. The last two times they tested this new technique, which bypasses the drill’s stuck feed mechanism by having the robot arm itself push the drill bit against the rock, the drilling did not succeed. It appeared the force applied by the robot arm to push the drill into the rock was not sufficient. The rock was too hard.

In these first attempts, however, they only used the drill’s rotation to drill, thus reducing the stress on the robot arm. The rotation however was insufficient. Thus, they decided with the next drill attempt to add the drill’s “percussion” capability, where it would not only rotate but also repeatedly pound up and down, the way a standard hammer drill works on Earth.

I suspect that they are proceeding carefully with this because this new technique places stress the operation of the robot arm, something they absolutely do not want to lose. By leaving Vera Rubin Ridge they return to the more delicate and softer materials already explored in the Murray Formation. This is very clear in the photo below, cropped from the original to post here, showing the boulder they have chosen to drill into, dubbed “Duluth,” with the successful drill hole to the right.
» Read more

Alien world

Meridiani Planum
So what is it we are looking at in the image above? I have reduced the resolution slightly to fit it here, but you can see the full resolution image by clicking on the picture.

Is it a marble or granite kitchen counter? Nah, the surface is too rough.

Maybe it’s a modern abstract painting that we can find hanging in the Museum of Modern Art in New York. Nah, it has too much style and depth. Abstract art is much more shallow and empty of content.

Could it be a close-up of a just-opened container of berry-vanilla ice cream, the different flavors swirling and intertwined to enhance the eating experience? No, somehow it looks too gritty for ice cream.
» Read more

Mars rover update: April 27, 2018

Summary: Curiosity’s exploration of Vera Rubin Ridge is extended, while an attempt by Opportunity to climb back up Perseverance Valley to reach an interesting rock outcrop fails.

For a list of past updates beginning in July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's traverse map, Sol 2030

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

Since my March 21, 2018 update, it has become apparent that the Curiosity science team has decided to extend the rover’s research on Vera Rubin Ridge far beyond their original plans. They have continued their travels to the northeast well past the original nominal route off the ridge, as indicated by the dotted red line on the traverse map above. Along the way they stopped to inspect a wide variety of geology, and have now moved to the north and have actually begun descending off the ridge, but in a direction that takes the rover away from Mount Sharp and its original route. As noted in their April 25 update,
» Read more

Mars rover update: March 21, 2018

Summary: Curiosity continues its exploration of Vera Rubin Ridge, including several drilling attempts. Opportunity is halfway down Perseverance Valley.

For a complete list of all past updates going back to July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's traverse map, Sol 1993

For the overall context of Curiosity’s travels, see Pinpointing Curiosity’s location in Gale Crater.

Since my February 8, 2018 update, the Curiosity science team has apparently been loath to leave Vera Rubin Ridge. They had begun the trek to the northeast that would take them towards the exit ridge heading to the southeast, as indicated by the dotted red line on the traverse map above, but then continued past that planned route to continue to the northeast. Along the way they attempted to drill twice using an improvised approach that they hoped would bypass the drill’s stuck feed mechanism, without apparent success.

The panorama below is looking to the west and south, as indicated by the yellow lines in the image above.
» Read more

Aligned erosion lines of Perseverance Valley

The uncertainty of science: Last week, while I was flying to Israel, the Opportunity science team announced the discovery of strange aligned erosion lines, what they are calling stone stripes, in Perseverance Valley.

The ground texture seen in recent images from the rover resembles a smudged version of very distinctive stone stripes on some mountain slopes on Earth that result from repeated cycles of freezing and thawing of wet soil. But it might also be due to wind, downhill transport, other processes or a combination.

…On some slopes within the valley, the soil and gravel particles appear to have become organized into narrow rows or corrugations, parallel to the slope, alternating between rows with more gravel and rows with less.

The origin of the whole valley is uncertain. Rover-team scientists are analyzing various clues that suggest actions of water, wind or ice. They are also considering a range of possible explanations for the stripes, and remain uncertain about whether this texture results from processes of relatively modern Mars or a much older Mars.

For those who are regular readers of Behind the Black, you already knew about a variation of this discovery back in November 2017, from my regular rover updates. Then, they discovered aligned groves in the gravel that looked to me like slickensides, erosion patterns produced by glacial activity. The science team told me, however, that they were favoring wind, not ice, as a primary cause, though that conclusion was far from certain.

In the press release last week, they focused more on the aligned erosion patterns in the fine gravel that appear to align perpendicular to the slope. Though they think they have found a comparable Earth-based phenomenon that might explain these patterns, it appears that the science team remains just as unsure of their cause as they are for the rocks.

Mars rover update: February 8, 2018

Summary: Curiosity remains on Vera Rubin Ridge, though it has begun moving toward the point where it will move down off the ridge. Opportunity remains in Perseverance Valley, though it has finally taken the north fork down.

Before providing today’s update, I have decided it is time to provide links to all previous updates, in chronological order. This will allow my new readers to catch up and have a better understanding of where each rover is, where each is heading, and what fascinating things they have seen in the past year and a half.

These updates began when I decided to figure out the overall context of Curiosity’s travels, which resulted in my March 2016 post, Pinpointing Curiosity’s location in Gale Crater. Then, when Curiosity started to travel through the fascinating and rough Murray Buttes terrain in the summer of 2016, I stated to post regular updates. To understand the press releases from NASA on the rover’s discoveries it is really necessary to understand the larger picture, which is what these updates provide. Soon, I added Opportunity to the updates, with the larger context of its recent travels along the rim of Endeavour Crater explained in my May 15, 2017 rover update.

Now to talk about the most recent news from both rovers!
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