Martian craters go splat!

Overview of the volcanic Tharsis Bulge on Mars

Cool image time! In continuing my exploration of this month’s Mars Reconnaissance Orbiter (MRO) image release, I found two interesting images of small craters, one as part of that image release, the other found completely by accident.

The map on the right, taken from the MRO HiRISE archive page, shows the locations of these two images. Both are located in the lava plains that surround the giant volcano Pavonis Mons, the central volcano of the three volcanoes to the east of Olympus Mons. Previously, I have done posts focusing specifically on both Pavonis Mons and Arsia Mons. Not only is the geology of these gigantic volcanoes fascinating, there is evidence that ancient glacial ice lurks in lava tubes on their slopes, making them potentially prime real estate for future explorers.

The first image, labeled #1 on the image above, was taken in January 2018 to get a better look at a small crater on the surrounding lava plains, and was part of the MRO March image release. I have cropped it to post here, focusing on the crater itself.

My first reaction on seeing the image was, “Did this impact not go splat when it hit?”
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More weird Mars geology

Low resolution of full image of crater

Cool image time! Yesterday the Mars Reconnaissance Orbiter team released 460 images taken by the spacecraft’s high resolution camera, HiRISE, as part of their normal and routine image release program. Obsessed with space exploration as I am, I like to scan through these new images to see if there is anything interesting hidden there that will show up eventually in a press release. For example, the first image in this release is a look at Vera Rubin Ridge and Curiosity. I would not be surprised if there is a press release soon using this image, probably aimed at outlining the rover’s future route up Mount Sharp. (The present overview traverse map is getting out of date.)

Sometimes however I find images that might never get a press release but probably deserve it. The image on the right, reduced in resolution to show here, is one such example. It is a strip taken from rim to rim across an unnamed crater located in the mid-northern latitudes of Mars, west of Olympus Mons. A review of past images by other Mars orbiters/probes suggests that no good high resolution image of this crater had ever been taken before.

If you click on the image on the right, or go to the actual image site, you can see the original in full resolution. It is definitely worthwhile doing this, because the strip shows some strange and inexplicable geology on the floor of the crater as well in its confusing central peak region. Numerous features appear to have been exposed by later erosion. The many small craters for example are I think what planetary geologists call pedestal craters. The surrounding terrain is less erosion-resistant, so as that terrain erodes away it leaves the crater behind, with its floor actually sitting higher than the surrounding flats.

What makes these craters even weirder however is that their rims appear to have eroded away even more than the surrounding terrain, so that all of these small craters (assuming that is what they are) have ringlike depressions surrounding a circular platform.

In the crater’s central peak region the terrain is even more strange. Sticking up out of the ground are some arched short ridgelines, which appear to have been exposed by erosion. That peak area however also has many strange flow features that I find completely baffling. It almost appears to me that as the molten peak area started to solidify after impact, someone went in with a stirring spoon and did some mixing!

The map below the fold provides the location context for this crater, with the crater’s location indicated by the arrow.
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Mars Reconnaissance Orbiter comes out of safe mode

On February 23 the Mars Reconnaissance Orbiter (MRO) engineering team was able to bring the spacecraft out of safe mode, after a low battery voltage reading caused it to shut down.

Mission team members brought MRO out of safe mode on Friday (Feb. 23), NASA officials said. The orbiter seems to be in good health overall; the battery voltage is back to normal, MRO is communicating with Earth, and temperatures and power levels are stable, agency officials said.

But MRO’s handlers haven’t put the orbiter back to work yet. “We’re in the diagnostic stage, to better understand the behavior of the batteries and ways to give ourselves more options for managing them in the future,” MRO project manager Dan Johnston, of NASA’s Jet Propulsion Laboratory in Pasadena, California, said in a statement. “We will restore MRO’s service as a relay for other missions as soon as we can do so with confidence in spacecraft safety — likely in about one week. After that, we will resume science observations.”

Overall this sounds like very good news.

Mars Reconnaissance Orbiter in safe mode

After detecting low battery voltage, Mars Reconnaissance Orbiter (MRO) went into safe mode on February 15.

The orbiter is solar-powered but relies on a pair of nickel-hydrogen batteries during periods when it is in the shadow of Mars for a portion of each orbit. The two are used together, maintaining almost identical charge during normal operations.

The spacecraft remains in communication with Earth and has been maintaining safe, stable temperatures and power, but has suspended its science observations and its service as a communications relay for Mars rovers. Normal voltage has been restored, and the spacecraft is being monitored continuously until the troubleshooting is complete.

It appears that all is under control. If MRO goes down, however it will a big loss for Mars research, as the spacecraft not only produces the highest resolution images of the ground, it also acts as one of several communications satellites between the Earth and the rovers on Mars. With two rovers there now, and at least two more planned for arrival in 2020, the loss of this communications link would be crippling.

Massive flow on Mars

Massive flow on Mars

Cool image time! The image on the right, cropped to post here, comes from a Mars Reconnaissance Orbiter image that shows a massive relatively recent and dark slope streak that emanates out from a single point on the surface. (Note that the release at this link rotates the image so that north points down. I have rotated back so that north points up.)

Streaks form on slopes when dust cascades downhill. The dark streak is an area of less dust compared to the brighter and reddish surroundings. What triggers these avalanches is not known, but might be related to sudden warming of the surface.

These streaks are often diverted by the terrain they flow down. This one has split into many smaller streaks where it encountered minor obstacles. These streaks fade away over decades as more dust slowly settles out of the Martian sky.

Point of origin for flow

Location of flow, west of Olympus Mons

The MRO release focuses on the fingerlike breakup of the flow as it descends into sand-dune filled plain. What is more interesting to me is the terrain where this flow originated. A close-up of that area from the full image, shown on the right, reveals a feature that could be a wash running in line with the flow’s origin, and leading uphill to a dark feature that is a likely a cliff face. (The light in this image is coming from the southeast.)

This location, at 15.2N latitude, 214.9E longitude and shown by the small cross in the image on the right and captured from this page, is west of Olympus Mons, the largest volcano on Mars. This suggests to me that the originating feature might be an outlet from a lava tube, from which water suddenly seeped out to produce this massive slope streak. A look at the mesa from which this flow came, cropped from the full image and posted below the fold, shows numerous similar slope streaks of varying ages flowing out of this mesa, with some very faint because they occurred farther in the past. Some are even within the bowl at the top of the mesa.

Whether these come from lava tubes is definitely unclear, and I suspect I will be told by geologists not likely. The seeps however do suggest strongly that this mesa might be a very good location for future colonists to look for underground water ice. Since clouds form on the western slopes of Arsia Mons, the southernmost of the three giant volcanoes to the east of Olympus Mons, and that past glacial activity has been documented there, I wonder if some of these same conditions might also exist here, on the nearby terrain west of Olympus Mons.
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A good health check for Mars Reconnaissance Orbiter

Link here. The article outlines in good detail the spacecraft’s present condition, which is excellent despite being in space since 2005, as well as outlining the measures being taken to keep it operational into the 2020s.

This item is probably the biggest cause for concern:

For example, some HiRISE images taken in 2017 and early 2018 show slight blurring not seen earlier in the mission. The cause is under investigation. The percentage of full-resolution images with blurring peaked at 70 percent last October, at about the time when Mars was at the point in its orbit farthest from the Sun. The percentage has since declined to less than 20 percent. Even before the first blurred images were seen, observations with HiRISE commonly used a technique that covers more ground area at half the resolution. This still provides higher resolution than any other camera orbiting Mars — about 2 feet (60 centimeters) per pixel — and little blurring has appeared in the resulting images.

HiRISE is the spacecraft’s primary instrument, and its most valuable. If it goes, we will lose our best tool right now for looking in detail at the Martian surface.

Weird Martian geology: Kaiser Crater

Kaiser Crater bedrock

Cool image time! This week JPL’s image site highlighted a picture taken by Mars Odyssey of the floor and dunes inside Kaiser Crater, located to the west of Helles basin in an area dubbed the Noachis Region.

To my eye, the Mars Odyssey picture was interesting, but not worth a post here on Behind the Black. However, I decided to take a look at what HiRise, the high resolution camera of Mars Reconnaissance Orbiter (MRO), had taken of the same area, just out of curiosity. A search at the master HiRise image site at the same latitude and longitude (-45 latitude, 180 longitude) showed that HiRise had imaged a part of the same area, but at much higher resolution.

When I zoomed in on this hi resolution image I came across some interesting and weird geology, cropped to show here on the right. Now this, I thought, is worth posting. Notice how the dark tracks, caused by dust devils, leave no tracks as they cut across the brighter areas. Obviously, these bright areas have no dust or sand, and are likely solid bedrock of some kind. The depressions might be craters, but they also might not. The raised area around the depressions might have been caused by the impact, or it might have been caused by some internal geological process that caused the depression while also raising the surrounding bulge. Since then the wind has been steadily depositing sand in the depressions, causing it to get trapped there.

The mysterious dark splotches of Mars

The dark splotches of Mars

Cool image time! The image on the right, cropped and reduced in resolution to post here, shows one particular dark splotch in a region with several similar dark areas.

Geologists aren’t quite sure what to make of the dark splotch in the middle of this image, one of several similar dark splotches that extend east and west for over 100 kilometers. From measurements made in infrared, this and other dark splotches have what we call “high thermal inertia,” meaning that it heats up and cools down slowly. Scientists use thermal inertia to assess how rocky, sandy, or dusty a place is. A higher thermal inertia than the surrounding area means it’s less dusty.

The image below the fold shows at full resolution the area indicated by the white box. It provides me no clue as to the cause for the darker color. I think we can speculate all we want, but the truth is that we simply don’t have enough information. We need a closer look, including boots on the ground, to figure this out.
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Mars or a bacterial cell?

Mars's southern polar regions

Cool image time! The image on the right, reduced and cropped to show here, was taken by Mars Reconnaissance Orbiter and shows just one spot in Mars’s southern polar regions. The surface only looks like bacteria because the basic structure of both is based on fractals. Scientists call this area “swiss-cheese terrain” because of the many holes that have opened up there.

The texture is very alien, bearing more of a resemblance to the universe of the very small, rather than the universe far, far away. But if this is a polar cap, then why does it not look like the polar caps on Earth? Indeed, there is no equivalent terrain observed here on Earth.

The so-called “Swiss cheese terrain,” referencing the numerous holes of the region, is a product of seasonal exchange between the surface and the Martian atmosphere. With a predominantly carbon dioxide content at 98 percent, the colder temperatures condense the gas out of the atmosphere to produce dry ice. The prevalence of water is more concentrated in the north, leaving the South polar region more carbon dioxide rich, and it’s this difference in composition that generates the unusual texture of the Swiss cheese terrain.

Be sure and take a look at the full resolution image. It is quite wild.

A Martian Journey

The exploration of the solar system has barely begun. Though we regularly get to see some spectacular images taken by the fleet of unmanned planetary probes that now circle or rove the various planets throughout the solar system, we mustn’t think we have seen very much. In truth, we have only gotten a very distant glimpse of only a few tiny spots, most of which have been viewed from very far away. Even at the highest resolution the images do not really tell us what it really will be like when we can stroll across those surfaces routinely.

To give you an idea of how much remains hidden, let’s take a journey inward from Mars orbit. The image below looks down on a good portion of the Martian globe, with the giant volcano Olympus Mons on the left, its three companion volcanoes in line to the east, and the vast valley of Valles Marineris east of these. This valley would cover the continental United States almost entirely, and extend significantly beyond into the oceans on either side.

Olympus Mons and Valles Marineris

This was essentially our first good look at Mars, taken from orbit by Mariner 9 in 1971.
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Near the Martian south pole

Near the Martian south pole

Cool image time! The image above, reduced and cropped to show here, shows an area at 87 degrees south latitude, not far from the south pole of Mars and in the region at the edge of its icecap of dry ice.

It is late summer in the Southern hemisphere, so the Sun is low in the sky and subtle topography is accentuated in orbital images.

We see many shallow pits in the bright residual cap of carbon dioxide ice (also called “Swiss cheese terrain”). There is also a deeper, circular formation that penetrates through the ice and dust. This might be an impact crater or it could be a collapse pit.

Because of the low Sun angle the bottom of the deep pit is poorly lit, making it hard to determine the pit’s nature. What can be seen at its bottom however are some patches of carbon dioxide ice, melting in the same manner as the dry ice in the surrounding terrain. Also, the dust pattern surrounding the pit indicates the prevailing winds at this location, consistently blowing to the northeast.

I am certain there will be additional photos taken of this pit, when the Sun is higher in the sky and its floor is thus better illuminated.

The soft avalanches of Mars

Krupac Crater gullies

Cool image time! The image on the right, reduced in resolution to show here, shows the gullies flowing down Krupac Crater on Mars. Be sure to check out the original, released today by the Mars Reconnaissance Orbiter science team, since they have enhanced the colors to bring out the sandy flows, noting as well that while most of these gullies are found in higher latitudes, this crater at 7.8 latitude has them as well.

Although large gullies (ravines) are concentrated at higher latitudes, there are gullies on steep slopes in equatorial regions. An enhanced-color closeup shows part of the rim and inner slope of Krupac Crater located just 7.8 degrees south of the equator.

The colors of the gully deposits match the colors of the eroded source materials. Krupac is a relatively young impact crater, but exposes ancient bedrock. Krupac Crater also hosts some of the most impressive recurring slope lineae (RSL) on equatorial Mars outside of Valles Marineris.

Below I have cropped out a small section showing, at full resolution, the termination point of one of these flows, indicating where this section is on the larger image to the right. This avalanche is clearly not liquid, though it has a very sandy and soft nature, suggesting — as some scientists have theorized — that liquid from below the surface might have played a part in its flow.

It is important in looking at these images to repeatedly remind yourself that the gravity here is about one third that of Earth, and thus the angle of repose will be different, and that avalanches will behave very differently in this environment. Moreover, Mars’s far colder climate will also effect things. The avalanche we are looking at could not happen in this way on Earth.

close-up of flow

The layered mesas of Mars

The mesas of Uzboi Valles

Cool image time! The image above, reduced and cropped to post here, shows the layered deposits and complex erosion that has taken place in this area of Mars dubbed Uzboi Vallis. As noted at the Mars Reconnaissance Orbiter post,

Layered deposits in Uzboi Vallis sometimes occur in alcoves along the valley and/or below where tributaries enter it. These deposits may record deposition into a large lake that once filled Uzboi Vallis when it was temporarily dammed at its northern end by the rim of Holden Crater and before it was overtopped and breached allowing water to drain back out of the valley.

It is important when looking at these erosion patterns, including the strangely shaped rippled sand dunes scattered through the larger image, that wind possibly plays an even more important part in causing erosion on Mars than liquid water might have in the far past.

Either way, the terrain here has the same stark and fascinating beauty as that seen in the American southwest. If we can ever make it possible to live on Mars, this will definitely be a place to visit when on vacation.

Strange beat-up Martian terrain

Strange terrain

Cool image time! The image above, taken by Mars Reconnaissance Orbiter and cropped to show here, reveals some very strange terrain, pounded by numerous impacts. The full color-enhanced image, which only covers a small area of the much larger strip image, shows a rough surface that on Earth would definitely be labeled “badlands.”

The very tiny cropped section above especially intrigued me because of the pronounced cliff that appears to be the north wall of a crater in which the east, west, and south walls have eroded away. The riverlet-like flows down the cliff-face are also intriguing, as are the cross-crossing features in the crater floor.

Make sure you look at the full images. Quite strange and fascinating. Even though the complete image strip isn’t color enhanced. it is filled with many interesting geological forms. I haven’t yet been able to find the spot shown by the color-enhanced section, but it is there nonetheless. I wonder if any of my readers can locate it.

The Earth and Moon, as seen from Mars

The Earth and Moon as seen from Mars

Cool image time! The image above, a composite of four separate Mars Reconnaissance Orbiter pictures, was taken on November 20, 2016.

Each was separately processed prior to combining them so that the moon is bright enough to see. The moon is much darker than Earth and would barely be visible at the same brightness scale as Earth. The combined view retains the correct sizes and positions of the two bodies relative to each other.

The reddish region on Earth is Australia, with Antarctica the bright white area below that.

Lace on Mars

Lace on Mars

Cool image time! The image on the right, cropped and reduced in resolution to show here, was taken by Mars Reconnaissance Orbiter June 21, 2016. It shows a region in the high northern latitudes, 80 degrees.

Some seasonal ice on Mars is transparent so that the sunlight penetrates to the bottom of the ice. Heat from this sunlight can turn the ice directly into a gas in a process called sublimation and this gas can scour channels in the loose dirt under the ice. Channels formed by sublimation of a layer of seasonal dry ice are so dense in this area that they look like lace. Gas flow erodes channels as it escapes to the surface of the overlying seasonal ice layer seeking the path of least resistance.

The resolution of the full image is 9.7 feet per pixel. This means that if Curiosity was driving across this surface we would see it. I guarantee however that Curiosity would not find driving here very easy. The ice surface is likely very delicate, and would likely cause any vehicle to bog down. The surface is also likely very alien-looking, which makes me very much want to see what it looks like, up close. This look will unfortunately have to wait, as we as yet do not have the right technology to do it. We would need I think a drone, capable of flying in Mars’s thin atmosphere.

The weird south pole of Mars

Mars' south pole region

Cool image time (literally)! The photo above, cropped slightly to show here, was taken by Mars Reconnaissance Orbit (MRO) in August 2016 and was released today as part of the monthly release of captioned images. And though it looks like a fractal computer-generated animation still, it is instead real, showing the strange and quite alien terrain that routinely forms at the carbon dioxide ice cap there.

The polar cap is made from carbon dioxide (dry ice), which does not occur naturally on the Earth. The circular pits are holes in this dry ice layer that expand by a few meters each Martian year. New dry ice is constantly being added to this landscape by freezing directly out of the carbon dioxide atmosphere or falling as snow. Freezing out the atmosphere like this limits how cold the surface can get to the frost point at -130 degrees Celsius (-200 F). Nowhere on Mars can ever get any colder this, making this this coolest landscape on Earth and Mars combined!

This region is about 4 degrees north of the south pole itself.

New details emerge of Schiaparelli crash site

Schiaparelli crash site

A new high resolution image from Mars Reconnaissance Orbiter’s HIRISE camera, reduced in resolution on the right, confirms that Schiaparelli crashed into the ground on October 19.

The scene shown by HiRISE includes three locations where hardware reached the ground. A dark, roughly circular feature is interpreted as where the lander itself struck. A pattern of rays extending from the circle suggests that a shallow crater was excavated by the impact, as expected given the premature engine shutdown. About 0.8 mile (1.4 kilometers) eastward, an object with several bright spots surrounded by darkened ground is likely the heat shield. About 0.8 mile (1.4 kilometers) south of the lander impact site, two features side-by-side are interpreted as the spacecraft’s parachute and the back shell to which the parachute was attached.

The center insert is a close-up of the impact site on the left, which clearly shows that the lander hit the ground hard, producing impact ejecta. That the rays are somewhat asymmetric also suggests that Schiaparellit hit the ground at an oblique angle.

MRO images Schiaparelli on Mars

before and after Schiaparelli

A comparison of images taken by Mars Reconnaissance Orbiter before and after Schiaparelli’s failed attempt to land on Mars have revealed changes that are likely the lander on the surface. The image on the right is a composite that I’ve made showing the two images. The black spot near the top and the white spot near the bottom are not in the first image.

It is thought that the white spot is likely Schiaparelli’s parachute, while the dark spot is thought to be the lander’s impact point.

The larger dark spot near the upper edge of the enlargement was likely formed by the Schiaparelli lander. The spot is elliptical, about 50 by 130 feet (15 by 40 meters) in size, and is probably too large to have been made by the impact of the heat shield.

The large size of the dark spot suggests that the lander hit the ground hard enough to create this large scar.

An avalanche on Mars, as it happens

Avalanche on Mars

Cool image time! In their routine monitoring for avalanches at the layered deposits at the Martian north pole, the Mars Reconnaissance Orbiter science team captured the avalanche on the right, as it happened.

This picture managed to capture a small avalanche in progress, right in the color strip. … The small white cloud in front of the brick red cliff is likely carbon dioxide frost dislodged from the layers above, caught in the act of cascading down the cliff. It is larger than it looks, more than 20 meters across, and (based on previous examples) it will likely kick up clouds of dust when it hits the ground.

They note that avalanches in this area of Mars are common in the spring when things are warming, and have been documented previously, but possibly not so dramatically.

The wild Martian terrain

Yardangs on Mars

This week’s image release from the high resolution camera on Mars Reconnaissance Orbiter illustrate well the wild and mysterious geology of the Martian surface. I include cropped sections from two images here, just to give you a taste. Go to the link to do your own exploring.

The image to the right is a cropped and scaled down version of the original image, so the details are not easily seen. Make sure you look at the original. The strange yardang ridges, all aligned alike, rise up out of a relatively smooth plain.

Yardangs are formed when a surface that is composed of materials of differing strengths (i.e., of both harder and softer materials) is shaped by the abrasive action of sand and dust carried by the wind. In this case, and given the proximity of the Apollonaris Patera volcanic center, we think that these wind-carved deposits are comprised of volcanic ash and pyroclastics that erupted from Apollonaris when it was last active in the not-too-distant geologic past. Over time, the softer materials (likely volcanic ash) were eroded away, leaving behind the harder materials in the form of elongated ridges that are parallel to the direction of the prevailing wind. The end result is a stunning, out-of-this-world display of yardangs, sculpted with the artistic chisel of the Martian wind.

That’s the theory, anyway. The actual geological process that formed these ridges is probably a lot more complicated.

The image below the fold illustrates the on-going surface activity on Mars.
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Evaporating dry ice chunks create gouges on Mars

Scientists think they have solved the mystery of the gouges that appear seasonally on some hillsides on Mars: Chunks of dry ice that slide down the slope and then evaporate, leaving no trace.

During the martian winter, carbon dioxide ice freezes over parts of the planet’s surface and sublimates back into a gas during the spring thaw. But according to the model presented here today at a meeting of the American Geophysical Union, chunks of warming dry ice may also break off from the crests of dunes and skid down slopes. This is no ordinary tumble—according to the model, the bases of the chunks are continually sublimating, resulting in a hovercraftlike motion that gouges the dune while propelling the ice down slopes. Solid ice that survives to the bottom settles into a pit before dissipating back into the atmosphere.

Dry ice evaporation creates the fresh gullies on Mars

New data from Mars Reconnaissance Orbiter shows that the fresh gullies that have been seen on the Red Planet are caused by dry ice evaporation, not liquid water as had been hoped.

Dundas and collaborators used the High Resolution Imaging Science Experiment (HiRISE) camera on MRO to examine gullies at 356 sites on Mars, beginning in 2006. Thirty-eight of the sites showed active gully formation, such as new channel segments and increased deposits at the downhill end of some gullies.

Using dated before-and-after images, researchers determined the timing of this activity coincided with seasonal carbon-dioxide frost and temperatures that would not have allowed for liquid water.

Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but is plentiful on Mars. It has been linked to active processes on Mars such as carbon dioxide gas geysers and lines on sand dunes plowed by blocks of dry ice. One mechanism by which carbon-dioxide frost might drive gully flows is by gas that is sublimating from the frost providing lubrication for dry material to flow. Another may be slides due to the accumulating weight of seasonal frost buildup on steep slopes.

The findings in this latest report suggest all of the fresh-appearing gullies seen on Mars can be attributed to processes currently underway, whereas earlier hypotheses suggested they formed thousands to millions of years ago when climate conditions were possibly conducive to liquid water on Mars.

Orbital images from Mars Reconnaissance Orbiter have confirmed that the mysterious rock that appeared near Opportunity was not ejecta from a nearby meteorite impact.

Orbital images from Mars Reconnaissance Orbiter have confirmed that the mysterious rock that appeared near Opportunity was not ejecta from a nearby meteorite impact.

The scientists theorized that there was a very remote chance that a nearby impact has thrown the rock into place, but the images show nothing nearby. Moreover, if there had been an impact we probably would have seen more rocks raining down all around. The images are further confirmation that the rock was kicked up by the rover itself as it rolled along.

Mars Reconnaissance Orbiter spots a new crater on Mars.

Mars Reconnaissance Orbiter spots a new crater on Mars.

The scar appeared at some time between imaging of this location by the orbiter’s Context Camera in July 2010 and again in May 2012. Based on apparent changes between those before-and-after images at lower resolution, researchers used HiRISE to acquire this new image on Nov. 19, 2013. The impact that excavated this crater threw some material as far as 9.3 miles (15 kilometers).

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