Tag Archives: Mars

Unearthly pit in Martian northern icecap

Giant pit in Martian North polar icecap
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Cool image time! It is spring in the Martian north, and thus the Sun has risen and remains in the sky for most if not all of each day, circling the horizon. As such, it illuminates polar icecap features that are strange and weird and hard to decipher based on our expectations here on Earth.

The photograph to the right, cropped and reduced to post here, is a good example. It was taken on September 20, 2019 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows a pit in the outer regions of the polar icecap, an area where that water icecap remains relatively stable, but that is also at a low enough latitude that summer sunlight can cause some erosion and sublimation of the ice.

The bottom of the pit is the center of the bullseye, with the layered features in the surrounding walls showing the many layers inside the icecap, built up over centuries, then slowly revealed as the ice in this pit slowly sublimated away.

You can get a better sense of what you are looking at by the overview map below.
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Sinkholes galore!

Sinkholes galore south of Olympus Mons
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Cool image time! The photograph to the left, cropped to post here, was part of the November image dump from the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a wind-swept dusty plain trending downhill to the west that is filled with more than a hundred depressions or sinkholes.

Unlike other pit images I have posted previously, this one is not focused on one particular pit or a string of pits. Instead, what makes it interesting is the large number of pits, scattered across the terrain in a random pattern. Their random distribution suggests that they are unrelated to any specific underground feature, such as a lava tube. Instead, some aspect of the underground geology here is causing the ground to sink at random points.

Below is an overview map showing where this dusty pit-strewn plain is located, indicated by the blue cross.
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Recent impact on Mars

Recent impact on Mars
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Cool image time! While finding recent impacts on Mars is not that unusual, the image to the right, found among the November image download from the high resolution camera on Mars Reconnaissance Orbiter (MRO), was dramatic enough that I decided that more people besides planetary scientists should see it. For scale the photograph is exactly 500 meters wide.

The photograph, taken September 26, 2019, also illustrates all the typical aspects of impact craters, and how they change the landscape.

This impact took place sometime between July 17, 2012 and January 4, 2018. We know this because it wasn’t there in a low-resolution image taken by the wide angle survey camera on MRO on the first date but was there when that same camera took another picture on the second date. Below is a side-by-side comparison of that July 17, 2012 image with the high resolution 2019 image above.
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Islands of ice on Mars and Pluto

Ice-filled craters near Martian south pole

In a paper published today in the Journal of Geophysical Research: Planets, scientists describe the identification of 31 ice-filled craters in the high southern latitudes of Mars. The map to the right, from their paper, shows the locations of these craters. The scientists also took a look at Pluto, and found five craters there that had similar features, though these were likely filled with frozen nitrogen, not water ice.

From their abstract:

These new 31 ice deposits represent an inventory of more than 10 trillion cubic meters of solid water, similar to but greater in number and volume than previously studied features near the north pole. Similar features of nitrogen ice may exist in craters on Pluto, suggesting that craters are a favorable location for the accumulation or preservation of ices throughout the Solar System. [emphasis mine]

These results are reinforced by the existence of glacial features found in numerous Martian craters at much lower latitudes, as well as the ice suspected to exist in the permanently shadowed craters on the Moon and Mercury. The processes that put the ice there on these different planets might be fundamentally different, but the results are the same: Ice accumulating within craters.

One aspect of these high latitude craters that remains somewhat unexplained is their asymmetrical distribution around the south pole, favoring the side of the planet south of Mars’ giant volcanoes. Moreover, in looking at the ice deposits within these craters the scientists found that the ice seemed to lie off-center within the craters, favoring a similar direction.

Based on the available data, the scientists theorize that the most likely cause of this asymmetric off-center pattern is wind. From their paper:

Basic physical arguments, mesoscale atmospheric models, and geomorphological observations predict deflection of winds emanating from the south pole by the Coriolis Force. Such deflection results in a general westward trend of winds (i.e., easterlies) in the south polar regions outside the [south pole cap], matching the [ice-filled crater] offsets we observe.

This correlation implies that wind is important in … formation and/or evolution [of craters with ice]. For the case where winds control [their] formation, katabatic winds may travel down the east side of crater walls and preferentially deposit ice on the west side of the crater via orographic precipitation as they flow up the west crater wall. This mechanism thus favors local accumulation of ice within craters.

I find it fascinating that the location of ice within craters on Mars might indirectly provide scientists with information about the planet’s global weather patterns. This unexpected connection highlights the need to dismiss no data or feature in trying to understand planetary formation. Unlikely things might answer our questions.

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A journey into the depths of Valles Marineris

Valles Marineris

Cool image time! Rather than start with the cool image, let’s begin with the long view. To the right is a wide mosaic of Valles Marineris on Mars, the largest known canyon in the solar system. About 2,500 miles long and 400 miles wide, this canyon is so large that it would cover most of the United States if put on Earth. The Grand Canyon, 500 miles long by 19 miles wide, could easily fit within it and not be noticed. In depth Valles Marineris is equally impressive, with a depth of more than four miles, about four times deeper than the Grand Canyon.

A closer view of the central regions of Valles Marineris

The white cross in the mosaic above is where we are heading. You can see it as the white box in the zoomed in overview to the right. This central part of Valles Marineris is named East Melas Chasma, and the red boxes indicate locations where the high resolution camera of Mars Reconnaissance Orbiter (MRO) has already taken images.

As you can see, we do not yet have many high resolution images of this part of the canyon floor. The white box is the most recent image, and is the subject of today’s post.
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Both methane and oxygen fluctuate in unison seasonally in Gale Crater

The uncertainty of science: According to a new science paper, data from Curiosity on Mars has now found that both methane and oxygen fluctuate in unison seasonally in Gale Crater.

From the paper’s abstract:

[T]he annual average composition in Gale Crater was measured as 95.1% carbon dioxide, 2.59% nitrogen, 1.94% argon, 0.161% oxygen, and 0.058% carbon monoxide. However, the abundances of some of these gases were observed to vary up to 40% throughout the year due to the seasonal cycle. Nitrogen and argon follow the pressure changes, but with a delay, indicating that transport of the atmosphere from pole to pole occurs on faster timescales than mixing of the components. Oxygen has been observed to show significant seasonal and year‐to‐year variability, suggesting an unknown atmospheric or surface process at work. These data can be used to better understand how the surface and atmosphere interact as we search for signs of habitability.

The data shows that the unexpected and so far unexplained seasonal oxygen fluctuation appears to track the same seasonal methane fluctuations. While biology could cause this signature, so could geological processes, though neither can produce these fluctuations easily.

Meanwhile, adding to the uncertainty were results from the two European orbiters, Mars Express and Trace Gas Orbiter. Both have failed to detect a June 19, 2019 dramatic spike in methane that had been measured by Curiosity.

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China unveils Mars lander during landing simulation test

The new colonial movement: China today unveiled to the international press its first prototype Mars lander, showing it attempting a simulated controlled descent on a gigantic test stand.

The demonstration of hovering, obstacle avoidance and deceleration capabilities was conducted at a site outside Beijing simulating conditions on the Red Planet, where the pull of gravity is about one-third that of Earth.

China plans to launch a lander and rover to Mars next year to explore parts of the planet in detail.

This is the first time I have heard anything about China sending a lander/rover to Mars in 2020. Previously the reports had discussed only sending an orbiter.

I have embedded video of the test below the fold. It shows the prototype hanging by many wires from the test stand, then dropping quickly, with its engine firing, before stopping suddenly, followed by an engine burst. While impressive, it did not strike me that China is even close to sending this spacecraft to Mars. The test only proved the spacecraft’s ability to do some maneuvering during descent. It did not show that it could land.

That the project’s designer said that landing would take “about seven minutes” also suggests that they are copying the techniques used by JPL to land Curiosity. Considering that JPL’s computers have been repeatedly hacked, including some hacks identified as coming from China, it would not surprise me if China has simply stolen those techniques.

I still expect them to launch an orbiter to Mars in 2020. Whether they also send a lander and rover remains to be seen.
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SpaceX completes 1st round of Starship’s Mars landing site images

All locations photographed of the candidate landing region for SpaceX's planned Mars missions

On August 28, 2019 I broke the story that SpaceX is beginning to obtain images of candidate Starship landing sites from Mars Reconnaissance Orbiter (MRO).

It now appears that SpaceX has completed its first round of Starship requests from MRO. In the image releases from Mars Reconnaissance Orbiter (MRO) since September, only three new Starship locations were taken, and all three were the unreleased candidate sites I noted in my September 16, 2019 update.

Below is the full list of all of the Starship images, their locations indicated on the map above by the numbered white boxes:

With the release of these last photographs, the initial list of proposed images of candidate Starship landing sites on Mars has apparently been completed. No additional images at any other locations appear to have been suggested. The MRO science team has taken stereo images of each one of the nine locations, eight of which were in Amazonis Planitia, and one in Phlega Montes.

This however is not the first round of pictures requested by SpaceX of the Arcadia Planitia region in connection with the company’s desire to land spacecraft on Mars.
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Polygons on Mars

Scallops and polygons on Mars
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Cool image time! The photograph on the right, cropped to post here, was taken on September 25, 2019 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and made public in its November image release. It shows the weird but very typical scalloped terrain, with its adjacent polygon pattern of fractures, found routinely in the northern lowland plains of Utopia Planitia on Mars. From an earlier captioned image from 2006 of these same features:

The scalloped depressions are typical features; a smooth layered terrain located between 40 and 60 degrees in both hemispheres. Scalloped depressions probably form by removal of ice-rich subsurface material by sublimation (ice transforming directly from a solid to a gaseous state), a process that may still be active today. Isolated scalloped depressions generally have a steep pole-facing scarp and a gentler equator-facing slope. This asymmetry is interpreted as being the result of difference in solar heating. Scalloped depressions may coalesce, leading to the formation of large areas of pitted terrain.

The polygonal pattern of fractures resembles permafrost polygons that form in terrestrial polar and high alpine regions by seasonal-to-annual contraction of the permafrost (permanently frozen ground). On Earth, such polygons indicate the presence of ground ice.

On Earth these polygons are most often seen in mud, usually suggesting a drying process where the ground contracts with the lose of fluid. On Mars the cracks probably also form from contraction, but not by the lose of fluid but the lose of water ice as it sublimates into a gas.

These polygons and scallops illustrate an important feature of Mars’ vast northern plains. On large scales these plains appear flat and featureless. Up close however many many strange features, like the polygons and scallops in this image, come into view.
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Mars’ seasonally vanishing carbon dioxide polar cap

Buzzell dunes, March 19, 2019
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Since the onset of the Martian spring in the northern hemisphere back in March of this year, scientists have been busy using the high resolution camera on Mars Reconnaissance Orbiter (MRO) to monitor the expected sublimation and disappearance of the cap of dry ice that falls as snow to become a winter layer mantling both the more permanent icecap of water 7,000 feet deep as well as the giant dune sand seas that surround that northern icecap.

The image on the right was first posted here on Behind the Black on June 6, 2019 as part of a long article describing that northern polar icecap and its annual evolution. It shows a set of dunes that Candice Hansen of the Planetary Science Institute in Arizona, who requested the image, has dubbed “Buzzell.” When that picture was taken in March, the frozen dry ice layer of translucent carbon dioxide still coated the dunes. The image’s darkness is because the Sun has just begun to rise above the horizon at this very high latitude location (84 degrees). The circular feature is likely a buried ancient crater, with the streaks indicating the prevailing wind direction blowing both sand and frost about.

On August 9, 2019 I provided an update on this monitoring, when new images of this same location were downloaded from MRO in April and June. MRO has now taken a new image of Buzzell, on October 2, 2019. Below the fold are all these images so that you can see the sublimation and disappearance of that dry ice layer over time.
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New InSight image of mole shows collapse of hole

View of InSight drill hole
Click for full movie.

The InSight science image has lifted the lander’s rover arm off the drill hole and taken a new series of images in an effort to discover what caused the mole to pop out during its most recent drilling effort.

The image to the right, cropped to post here, was the first in a short movie made from all the images taken over the course of a day. The sequence shows the change in shadows, which helps define the situation in the hole.

This image however I think tells all. It shows that the walls of the hole have collapsed all around the mole, widening it further. It also shows that, once the mole popped out to lean sideways against the left wall, much of that material then fell into the hole, refilling it. These facts are very evident when today’s image is compared with this image from October, taken prior to the most recent drilling effort. The hole has become much wider, there is more material inside it, and the mole is now much farther out.

All these facts bode ill for the mole ever succeeding in drilling down the planned fifteen or so feet to insert a heat probe into the interior of Mars in order to take the first ever measure of the planet’s interior.

An overall assessment of this NASA mission is not very positive. The contribution from its international partners is especially bad. The mission was launched two years late because the French effort to build the seismometer failed. NASA had to subsequently give the job to JPL to get it done. Now the heat sensor is a failure, because the German-built mole has failed to get the heat sensor where it needs to be.

The seismometer and heat sensor were InSight’s only science instruments. This means that we will likely only get results from one.

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Sightseeing Central Butte on Mars

Central Butte in foothills of Mt Sharp

Overview showing perspective of panorama

Curiosity has now roved to the very foot of Central Butte, where it has been taking close-up and panorama images of the butte and its geological layers. The panorama above was created from three Curiosity navigation images taken on Sol 2577 (November 6, 2019), here, here, and here.

The overview on the right, based on Curiosity’s position about ten sols ago slightly farther from the butte, still indicates roughly with the yellow lines the area photographed in this panorama. The dotted red line indicates Curiosity’s initial planned route.

Following that route Curiosity will eventually climb up onto the plateau beyond this butte, approaching that higher terrain farther to the west. Once they do, however, they will no longer have access to the geological layers below the surface. Central Butte gives them a window into those layers, which is why they are going to spend some time at this location, first by taking a few sols looking at the butte at this point, then circling around to study its back side.

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Rover update: October 28, 2019

Summary: Curiosity finally on the move after several months drilling two adjacent holes in the clay unit. Yutu-2 continues roving west, has it now operates during its eleventh lunar day on the far side of the Moon.

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

Curiosity's present location in Gale Crater
Click for original full image.

Curiosity

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

I have not done any of my regular rover updates since May 30, 2019 because it was simpler to do individual updates for both Curiosity and Yutu-2, the only working rovers presently on other worlds. (If things had gone well, which they did not, we would have had two other lunar rovers in the past six months, one from Israel and one from India, but both crashed during landing.)

However, since Curiosity is finally on the move after spending several months at one location, where it drilled two holes in the clay unit (the material from one used in a wet cup experiment to look for organic life) it is time to update my readers on where Curiosity is and where it is heading.

The first image above and to the right is an annotated overview of Curiosity’s present position, moving south to a line of buttes which scientists have determined delineates the transition from the clay unit to a new geological layer they have dubbed the Greenheugh Pedimont. The yellow lines indicate the area seen in the panorama below, created from two photographs (here and here) taken by the rover’s navigation camera.
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InSight’s mole has popped out of its hole

InSight's mole, out of the ground
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In a setback for its renewed digging effort, the mole drill on InSight has apparently bounced out of its drilled hole during the most recent drilling, soon after engineers had increased the rate of hammer strokes.

The image to the right shows the mole, the white cylinder on the left, with the scoop of the robot arm mostly covering the hole in its effort to pin the mole in position.

“While digging this weekend the mole backed about halfway out of the ground,” the mission announced via a pair of tweets Oct. 27. “Preliminary assessment points to unexpected soil properties as the main reason.”

…The mission added that one possibility is soil is falling in front of the mole, filling the hole. “Team continues to look over the data and will have a plan in the next few days.”

Without question the alien and fluffy properties of the soil appears to be the problem. Based on how the mole is leaning, I wonder if the left wall of the hole began to widen and collapse, as had the rest of the hole during initial drilling, thus defeating the purpose of the robot arm’s effort to pin the mole in place.

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Ancient glacier flows on Mars

Ancient glacial flow in Euripus Mons
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Cool image time! In the recent download of images from the high resolution camera of Mars Reconnaissance Orbiter (MRO), I found the image on the right, rotated, cropped, and reduced to post here. It shows an example of the many glacial flows coming off of the slopes of Euripus Mons, the sixteenth highest mountain on Mars.

We know these are glaciers because data from SHARAD, the ground-penetrating radar instrument MRO, has found significant clean ice below the surface, protected by a debris layer that insulates it. As planetary scientist Alfred McEwen of the Lunar & Planetary Laboratory in Arizona explained to me in a phone interview yesterday,

These are remnant glaciers. Basically they form like glaciers form. They are not active or if they are they are moving so extremely slowly that effectively they are not active.

If you look close, you can see that this particular glacier was made up of multiple flows, with the heads or moraines of each piled up where each flow ended. In addition, this overall glacier appears to have been a major conduit off the mountain, following a gap between more resistant ridges to the east and west.

The sequence of moraines suggest that when the glacier was active, it experienced alternating periods of growth and retreat, with the growth periods being shorter and shorter with time. As a result each new moraine was pushed less distance down the mountain as the previous one.

Euripus Mons is interesting in that it has a very large and distinct apron of material surrounding it, as shown in the overview image below.
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Curiosity takes selfie next to two of its most important drill holes

Curiosity and its most recent drill holes
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The Curiosity science team today released a beautiful mosaic of the rover, stitched from 57 different images. The photo at the right, cropped and reduced to post here, is the annotated version of that image. It shows the rover’s two most recent drill holes to the left. As the view looks away from Mount Sharp, you can see in the distance Vera Rubin Ridge, the floor of the crater, and its rim on the far horizon.

The two drill holes are significant because of the chemical experiment that Curiosity is subjecting the material from those holes.

The special chemistry experiment occurred on Sept. 24, 2019, after the rover placed the powderized sample from Glen Etive 2 into SAM. The portable lab contains 74 small cups used for testing samples. Most of the cups function as miniature ovens that heat the samples; SAM then “sniffs” the gases that bake off, looking for chemicals that hold clues about the Martian environment billions of years ago, when the planet was friendlier to microbial life.

But nine of SAM’s 74 cups are filled with solvents the rover can use for special “wet chemistry” experiments. These chemicals make it easier for SAM to detect certain carbon-based molecules important to the formation of life, called organic compounds.

Because there’s a limited number of wet-chemistry cups, the science team has been saving them for just the right conditions. In fact, the experiment at Glen Etive is only the second time Curiosity has performed wet chemistry since touching down on Mars in August 2012.

This time however was the first time they had used a wet chemistry cup on material from a drill hole. That they were able to do this at all is a testament to the brilliant innovative skills of the rover’s engineers. They had been holding off doing a wet chemistry analysis from drill hole material until they got to this point, but on the way the rover’s drill feed mechanism failed. It took more than a year of tests and experimentation before they figured out a way to bypass the feed mechanism by using the arm itself to push the drill bit into the ground. That rescue made possible the wet chemistry experiment that they initiated on September 24.

The results, which are eagerly awaited, won’t be available until next year, as it will take time for the scientists to analyze and publish their results.

Curiosity meanwhile has moved on, leaving this location where it had remained for several months to march in the past week southward back towards its long planned route up Mount Sharp.

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Big landslides on Mars might not require ice

According to a new paper, scientists now think the biggest and longest landslides found on Mars might not require a base of ice on which it could slide such extensive distances.

The findings, published today in Nature Communications, show for the first time that the unique structures on Martian landslides from mountains several kilometres high could have formed at high speeds of up to 360 kilometres per hour due to underlying layers of unstable, fragmented rocks.

This challenges the idea that underlying layers of slippery ice can only explain such long vast ridges, which are found on landslides throughout the Solar System.

First author, PhD student Giulia Magnarini (UCL Earth Sciences), said: “Landslides on Earth, particularly those on top of glaciers, have been studied by scientists as a proxy for those on Mars because they show similarly shaped ridges and furrows, inferring that Martian landslides also depended on an icy substrate. “However, we’ve shown that ice is not a prerequisite for such geological structures on Mars, which can form on rough, rocky surfaces. This helps us better understand the shaping of Martian landscapes and has implications for how landslides form on other planetary bodies including Earth and the Moon.”

The lighter gravity of Mars, about one third of Earth’s, is part of the explanation, though many other factors are involved. Either way, this is one more data point in the evidence that the though geology on Mars might look like what we see on Earth, it is likely very different than we expect, due to the alien nature of Mars itself.

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Mars2020 budget overruns threatening other missions

The significant budget overruns for NASA’s Mars 2020 mission, now expected to exceed a billion dollars, could now pose a threat to other planetary projects.

The cost of Mars 2020 has been growing for a while. The initial proposed cost for the rover, when the mission was announced in 2012, was $1.5 billion. Six years on, a 2018 Government Accountability Office (GAO) report showed that the cost had soared to $2.46 billion. And in NASA’s latest budget, the overrun looks set to grow by as much as 15% (or about another $360 million) beyond that last 2018 estimate, although the latest numbers are yet to be confirmed.

The irony is that Mars 2020 was established by the Obama administration as part of its effort to significantly cut back on NASA’s entire planetary program. The idea was to save money by simply rebuilding Curiosity.

As is typical for these projects, the scientists pushed for cutting edge instruments, and it is these instruments that have caused the overages. Meanwhile, many of those 2012 cuts pushed by Obama never happened, or were simply funneled into different planetary projects that were approved later.

No one who is involved in any way with the U.S. government today knows anything about keeping their effort on budget and on time. No one. And the result is increasing debt and what will certainly be bankruptcy for everyone, at some point, thus causing everything to shut down.

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InSight’s digging problems reveal the alienness of Mars’ soil

Even as InSight’s mole shaft driller shows signs of working, its difficulties in digging into the Martian soil has revealed how truly alien that soil is from what we normally expect.

[U]nlike typical holes dug here on Earth, the one excavated by InSight’s mole has no lip of dirt around its rim, Hoffman said. “Where did the soil go?” he said. “Basically, it got pounded back into the ground, so it seems like it’s very cohesive, even though it’s very dusty.”

And this is a weird combination of characteristics, strongly suggesting that Mars dirt is alien in more ways than one. “The soil properties are very different than anything we’ve ever seen on Earth, which is already a very interesting result,” Hoffman said.

That the soil of Mars is alien should not be a surprise. The planet’s dusty nature, combined with its light gravity and lack of life, practically guaranteed that the soil would have different and unexpected properties. What is disturbing is that it appears this likelihood was not considered in the slightest by the German engineers who designed the mole for digging.

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Lava-draped terrain on Mars

Lava surrounding hill and partly covering crater
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Hill surrounded by lava flows
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Cool image time! Continuing this week’s series of lava-related images from Mars (previous posts here, here, and here), today’s post is ironically the first to actually show lava flows.

The two images to the right, reduced and cropped to post here, are sections taken from an uncaptioned picture, titled “Lava-Draped Surface in Cerberus Palus” and found in the most recent download from the high resolution camera on Mars Reconnaissance Orbiter (MRO).

It is obvious why the MRO scientists gave this image this title. The hills in both pictures clearly seem to stand up like islands in a surrounding sea of frozen lava. Older craters, created prior to the lava flow, are partly obscured by the lava flows, their interior floors filled and their rims broken as the lava flooded this region.

Nor are these the only high points captured in the image that this flood of lava inundated. If you look at the full image there is even a low mound where it appears the surrounding lava flood worked its way up the hill’s gently sloping flanks only to freeze just before it completely covered the top of the mound.

The location of this image, shown by the red box in the overview map below and to the right, gives us a hint where the lava came from, though the distances involved to the nearest giant volcano, Elysium Mons, are so large it is likely that this flow is not directly linked to that volcano.
» Read more

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Sinkholes on Mars

Collapse pit on Mars
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Cool image time! In this week’s exploration of Martian geology that is reminiscent of Earth-based lava geology, today’s image is of a collapse pit in Ceraunius Fossae, the vast region of north-south fissures found to the south of the volcano Alba Mons. The photo to the right, cropped to post here, zooms in on that pit.

The picture was part of the most recent image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO). What makes it especially interesting is the sharpness of its rim, in comparison to the collapse channel to the east. This suggests the pit is younger and fresher than the channel, and happened more recently. This also implies that the voids below the ground in which the surface is sinking are either still there, or due to on-going processes might be still be forming (like caves are on Earth).

For example, if there is underground ice, temperature changes or even thermal heat from the nearby giant volcanoes could melt that underground ice periodically, allowing it to flow and erode the surrounding material, forming voids. That this pit is located at 30 degrees north latitude, just inside the northern hemisphere band where glaciers are found, adds weight to this possibility.

The image below, reduced and rotated so that north is to the left, shows the entire sequence of collapse channels, with the more distinct pit from above in the bottom center of the picture.
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A discontinuous Martian channel

Discontinuous channel near Olympica Fossae
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Close-up of channel

Time for more strange Martian geology! As I said in my post yesterday of a cool image of skylights into what might be a Martian lava tube, this is lava week on Behind the Black. The image at the right, rotated, reduced, and cropped to post here, is similar to yesterday’s photograph, showing a line of sinks and depressions that strongly suggest the existence of an underground lava tube.

The problem with this theory is that at present we really have no idea what flowed here. It could have been lava, but it also could have been mud, water, ice, or some as yet unimagined Martian geological process.

The image was part of the most recent image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO), and was uncaptioned. The top image shows the whole channel as captured by the photograph, with the white box indicating the area covered by the second image, posted here at full resolution.

Though the overall slope of the terrain here is downhill to the west, the grade is relatively shallow, so there is no guarantee that the local slope of this particular channel follows that trend. Downhill could be either to the west or the east.

The reason I favor lava (as an amateur geologist) is the location of this channel, as shown in the overview map below and to the right.
» Read more

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Europe schedules new parachute tests for ExoMars 2020

Following the failure on all previous tests of the parachutes for its ExoMars 2020 Mars lander, the European Space Agency has now made some design changes and is planning to do additional tests in the first quarter of 2020.

ESA has also requested support from NASA to benefit from their hands-on parachute experience. This cooperation gives access to special test equipment at NASA’s Jet Propulsion Laboratory that will enable ESA to conduct multiple dynamic extraction tests on the ground in order to validate any foreseen design adaptations prior to the upcoming high altitude drop tests.

The next opportunities for high altitude drop tests are at a range in Oregon, US, January–March. ESA is working to complete the tests of both the 15 m and 35 m parachute prior to the ExoMars project’s ‘qualification acceptance review’, which is planned for the end of April in order to meet the mission launch window (26 July–11 Aug 2020).

Their schedule is incredibly tight, since their launch window to Mars is in July 2020, and if they fail to meet it the launch will have to be delayed two years until the next launch window.

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InSight’s mole digs an inch

The InSight science team today tweeted that their attempt to use the lander’s robot arm to help the mole push downward in its effort to insert a heat sensor fifteen feet into the Martian interior has resulted in a gain of about an inch or three centimeters.

This success, small as it seems, is important in that it proves that the reason the drill had been stopped penetrating downward was not because of the presence of a rock, but because the drill hole had become so wide that the drill no longer had side friction to hold it in place. They are now using the arm to give the mole that friction.

The goal was to insert to heat sensor five meters or about sixteen feet into the ground. They are presently a little over a foot down. If this effort has really succeeded, they can then proceed to drill the remaining distance.

One issue however is whether the unexpected weak and porous nature of the soil, which allowed the hole to become so wide, might affect any data produced by the heat sensor. This is presently unknown, but it is a significant question that the scientists involved must ask. If the sensor ends up inside a very wide shaft that allows the surface environment to reach the sensor then it will not really be measuring the temperature of the Martian interior.

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Skylights into Martian lava tube?

Possibly connected skylights into lava tube
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Close-up of skylights
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Cool image time! In the archive of images from the high resolution camera on Mars Reconnaissance Orbiter (MRO) I came across the uncaptioned image on the right, dubbed “Possibly Connected Lava Tube Skylight Pair in Tharsis Region.”

The top image, cropped and reduced to post here, is a wide view, showing a narrow depression oriented in a north-south direction. Downhill is to the north, with the caldera of the giant volcano Arsia Mons to the south. The white box indicates the area covered by the bottom image, cropped and expanded to post here. Within this close-up are two dark spots, each about 150 feet across.

The two dark spots surely look like small pit openings. Their alignment with the north-south depression strongly suggests that an underground lava tube is below. That this depression is also aligned with the downhill slope further reinforces this supposition.

The depression itself also aligns with the gigantic fault that runs from the northeast to the southwest through all three of the giant Tharsis Bulge volcanoes. Arsia Mons is the southernmost of the three. It is also where that fault is most clearly expressed by two dramatic breaks in the volcano’s rim in the northeast and southwest, as seen in the overview image below. Scientists have taken of lot of images of these breaks in an effort to better understand the geology and how it fits in with the formation of the volcanoes.

Overview of Arsia Mons

However, a review of the entire image archive of MRO’s high resolution camera shows that scientists have taken very few close-up images in this region. The black box in the overview map on the right is the location of this image. As of now, only three other high resolution images, as indicated by the white boxes, have been taken by MRO of this part of the volcano’s north slope.

That the skylights and depression align with this giant fault is not evidence that this supposed lava tube is linked to that fault. Lava will flow down the mountain’s slopes, fault or no fault. At the same time, the fault’s existence is also going to encourage north-south cracks and fissures, which in turn could have served as a convenient flow route for the lava. Without a closer look, on site, it is hard to know one way or the other..

I’ve located a few more lava related cool images in the MRO archive, so I’m going to make this week lava week on Behind the Black. Stay tuned!

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Ice! Ice! Everywhere on Mars ice!

Ice scarp in Milankovic Crater
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In January 2018 scientists announced the discovery of exposed ice in a number scarp cliff faces found in the high-mid-latitudes of Mars.

These scarps, which have so far been found in one southern 50-55 degree latitude strip and in one crater, Milankovic, at the same latitude in the north, are important because they are one of the first places on Mars in its lower latitudes where we have found ice actually exposed and visible, not buried like the many buried glaciers very near the surface found in the 30 to 60 degree northern and southern latitude bands.

Since that press announcement, scientists have been monitoring these sites for changes, as well as expanding their survey to see if they can locate more of these scarps.

Overview map

My previous posts on this subject were mostly focused on that southern strip near Hellas Basin, as shown on the map on the right. In reviewing the most recent image download from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I noticed that the only new images of ice scarps were taken in the northern location, in Milankovic Crater, as indicated by the white dot north of Olympus Mons. The first image above shows the north-facing scarp of one of these images, cropped to focus in on the color section where, if you look close, you will see a strip of blue across the base of the scarp. That’s the ice layer, exposed as the scarp sublimates away over time from the north to the south.

over view of all MRO images taken so far in Milankovic Crater

This scarp, labeled #2 on the overview map of Milankovic Crater on the right, is located inside the crater’s eastern rim. The second image, posted below and labeled #1 on the overview map, shows a wider area of several ice scarps located on the inside of the crater’s southwestern rim.

The red boxes in the overview map indicate all the images taken by MRO inside this crater. If you go to the camera’s archive and focus in on Milankovic Crater at 54.5 degrees north latitude and 213.3 degrees longitude, you can then click on each red box to see the high resolution image. In practically every image along the crater’s inside rim can be found numerous scarps.
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Mars Express looks at Martian river relic

Mars Express perspective view of Nirgal Vallis
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The Mars Express science team today released a mosaic produced by the orbiter’s high resolution camera of the 300 hundred mile long relic river valley Nirgal Vallis. The image to the right, reduced to post here, is the oblique view that was produced by computer using the camera’s stereo images.

This ancient valley system is named Nirgal Vallis, and was once filled with running water that spread across Mars. By exploring the characteristics of the surrounding craters, scientists estimate the system’s age to be between 3.5 and 4 billion years old.

The part of Nirgal Vallis captured in these images lies towards the western end of the river system, where it is slowly spreading out and dissipating; the eastern end is far less branched and more clearly defined as a single valley, and opens out into the large Uzboi Vallis – the suspected location of a large, ancient lake that has long since dried up.

Nirgal Vallis is a typical example of a feature known as an amphitheatre-headed valley. As the name suggests, rather than ending bluntly or sharply, the ends of these tributaries have the characteristic semi-circular, rounded shape of an Ancient Greek amphitheatre. Such valleys also typically have steep walls, smooth floors, and, if sliced through at a cross-section, adopt a ‘U’ shape. The valleys pictured here are about 200 m deep and 2 km wide, and their floors are covered in sandy dunes; the appearance of these dunes indicates that martian winds tend to blow roughly parallel to the valley walls.

Unlike the high resolution camera on Mars Reconnaissance Orbiter (MRO), which is for taking close-up images of specific surface features, Mars Express is producing a high resolution survey of the entire planet. Its camera does not have quite the same resolution, but as it is taking wider images that’s okay.

What is unfortunate is the European Space Agency’s policy for releasing those images. Unlike MRO, they do not make them all available to the public instantly. Instead, they periodically do press releases like today’s, highlighting a specific region or single large feature. As a result, Mars Express does not get the press it deserves.

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Swirls and layers in Martian depression

Close-up on swirls and layers

Context of depressions in Columbus Crater
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Cool image time! The southern highlands of Mars is littered with numerous craters, making it look from a distance not unlike the Moon. A closer inspection of each crater and feature, however has consistently revealed a much more complex history than seen on the Moon, with the origins of many features often difficult to explain.

The two images on the right, rotated, cropped, and reduced to post here, shows one such feature in the floor of one southern highlands crater, dubbed Columbus Crater. The top image is a close-up of the area shown by the box in the bottom image.

The uncaptioned full photograph was taken on May 20, 2019 by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and was simply titled “Depression in Columbus Crater.” Since the photo included two large depressions, as shown in the wider view in the bottom image, I’m not sure which depression this title refers. In both cases the features do not appear to be impact craters. The top depression is far too irregular, while both do not have the upraised rims that are found on most impact craters.

I have zoomed into the top depression because of its many swirls and layers. On Earth such terrain is usually caused by either water or wind erosion, slowly carving a smooth path across multiple geological layers. Here, there is no obvious evidence of any flows in any direction. Something ate out the material in this depression, exposing the many layers, but what is not clear.

The lower depression reminds me of sinkholes on Earth, where the ground is subsiding into a void below ground The same process could have also formed the top depression.

The surrounding terrain is equally baffling, resembling the eroded surface of an ice block that has been sprayed with warm water. In fact, the entire floor of Columbus Crater appears to have intrigued planetary scientists, as they have requested a lot of images of it from MRO. So far they do not have enough of these images to produce a full map. Since the terrain appears to change drastically over short distances, it is therefore hard to fit the geology of each image together. The overall context is missing.

When I first saw this image I tried to reach the scientist who requested it in the hope he might provide me a more nuanced explanation of what we see here, but despite repeated requests he never responded. Therefore let me propose one theory, based on my limited knowledge of Martian geology.
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The drying out of Mars

Edge of wash
The Murray formation as seen in 2017

A new paper based on data gathered by the rover Curiosity in 2017 when it was lower on the slopes of Mount Sharp, as well as data obtained more recently at higher elevations, has confirmed that the past Martian environment of Gale Crater was wetter, and that deeper lakes formed lower down, as one would expect.

In 2017 Curiosity was traveling through a geological layer dubbed the Murray formation. It has since climbed upward through the hematite formation forming a ridge the scientists dubbed Vera Rubin Ridge to reach the clay formation, where the rover presently sits. Above it lies the sulfate-bearing unit, where the terrain begins to be get steeper with many very dramatic geological formations.

Looking across the entirety of Curiosity’s journey, which began in 2012, the science team sees a cycle of wet to dry across long timescales on Mars. “As we climb Mount Sharp, we see an overall trend from a wet landscape to a drier one,” said Curiosity Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Pasadena, California. JPL leads the Mars Science Laboratory mission that Curiosity is a part of. “But that trend didn’t necessarily occur in a linear fashion. More likely, it was messy, including drier periods, like what we’re seeing at Sutton Island, followed by wetter periods, like what we’re seeing in the ‘clay-bearing unit’ that Curiosity is exploring today.”

Up until now, the rover has encountered lots of flat sediment layers that had been gently deposited at the bottom of a lake [the Murray Formation]. Team member Chris Fedo, who specializes in the study of sedimentary layers at the University of Tennessee, noted that Curiosity is currently running across large rock structures [Vera Rubin Ridge and the clay formation] that could have formed only in a higher-energy environment such as a windswept area or flowing streams.

Wind or flowing water piles sediment into layers that gradually incline. When they harden into rock, they become large structures similar to “Teal Ridge,” which Curiosity investigated this past summer [in the clay formation]. “Finding inclined layers represents a major change, where the landscape isn’t completely underwater anymore,” said Fedo. “We may have left the era of deep lakes behind.”

Curiosity has already spied more inclined layers in the distant sulfate-bearing unit. The science team plans to drive there in the next couple years and investigate its many rock structures. If they formed in drier conditions that persisted for a long period, that might mean that the clay-bearing unit represents an in-between stage – a gateway to a different era in Gale Crater’s watery history.

None of these results are really surprising. You would expect lakes in the flatter lower elevations and high-energy streams and flows in the steeper higher elevations. Confirming this geology however is a big deal, especially because they are beginning to map out in detail the nature of these geological processes on Mars, an alien world with a different make-up and gravity from Earth.

Below the fold is the Curiosity science teams overall map, released in May 2019, showing the rover’s future route up to that sulfate unit, with additional annotations by me and reduced to post here.
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Weird glacial features in Martian crater

weird glacial feature in crater on Mars
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Cool image time! In reviewing today’s October release of new images from the high resolution camera of Mars Reconnaissance Orbiter (MRO), I came across the strange geology shown in the image to the right, rotated, cropped, and reduced to post here.

The uncaptioned image calls these “glacial features within crater.” The crater is located at 35 degrees north latitude in Arabia Terra, one of the more extensive regions of the transition zone between the northern lowlands and the southern highlands. It is also located within the northern band from 30 to 60 degrees latitude where most of the buried Martian glaciers are found.

The most abundant type of buried glaciers are called concentric crater fill (CCF) because they are found inside craters, and often show decay in a concentric manner. This weird feature likely falls into that category, though I would hardly call these glacier features concentric.

I’m not even sure if this is an impact crater. If it is, its rim has been heavily obscured, making it look instead like an irregular depression with one outlet to the south. In fact, I suspect it is possibly one of the lakes that scientists believe pepper this part of Arabia Terra and might have contained liquid water two to three billion years ago. That water would have later frozen, and possibly become covered by dust and debris to protect it.

According to present theories, Mars is presently in a period where its mid-latitude glaciers are shrinking, the water sublimating away and being transported back to its poles. The weird formations here suggest this process. Imagine what happens when you spray warm water on a big block of ice. It dissolves, but randomly to form weird shapes.

In this case the glacier is shrinking randomly where the ice has gotten exposed. In the thin Martian atmosphere, it transitions directly from a solid to a gas, sublimating into the atmosphere to leave these inexplicable shapes.

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