Tag: Mars

The soft landslides of Mars

12:14 pm

A soft avalanche on Mars

Context image of landslide

The light gravity of Mars, combined with different materials, a lot of dust, and a geological history different from Earth, produces events that — though reminiscent of similar geological events on Earth — are definitely not the same.

The image above, cropped and reduced to post here, was taken by the high resolution camera on Mars Reconnaissance Orbiter (MRO) and was one of the many uncaptioned images released in the November archive. If you click on the image you can see the full resolution version. It shows the tongue of a landslide inside a crater located in the planet’s southern highlands.

You can immediately see why I call it a soft landslide. The craters on its top are barely visible, as if they hit a soft surface that absorbed most of the impact. The grooves spreading southward in the slide suggest that this solid material flowed almost like mud. And the soft, smooth surface head of the slide suggests an almost liquid-like flow. As far as I can tell, this landslide had few large boulders. It was made up instead of small particles of about the same size.

To the right is an image showing the wider context of the above image, taken by Mars Odyssey and cropped and annotated by me to post here. The white box shows the entire area photographed by the full resolution image of the landslide, with the tongue of the landslide at the bottom of the box. If you look at the floor of this crater, you can see what looks like the ghost of a past smaller impact, seemingly buried in either a field of lava or soft dusty regolith. The smoothness of the crater floor also suggests a material softness, allowing it to settle into a pondlike featureless flat plain.
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NASA picks Mars 2020 landing site: Jezero Crater

11:00 am

Jezero Crater

NASA has picked Jezero Crater has the landing site for its as yet unnamed 2020 Mars rover.

Jezero Crater is located on the western edge of Isidis Planitia, a giant impact basin just north of the Martian equator. Western Isidis presents some of the oldest and most scientifically interesting landscapes Mars has to offer. Mission scientists believe the 28-mile-wide (45-kilometer) crater, once home to an ancient river delta, could have collected and preserved ancient organic molecules and other potential signs of microbial life from the water and sediments that flowed into the crater billions of years ago.

Jezero Crater’s ancient lake-delta system offers many promising sampling targets of at least five different kinds of rock, including clays and carbonates that have high potential to preserve signatures of past life. In addition, the material carried into the delta from a large watershed may contain a wide variety of minerals from inside and outside the crater.

The geologic diversity that makes Jezero so appealing to Mars 2020 scientists also makes it a challenge for the team’s entry, descent and landing (EDL) engineers. Along with the massive nearby river delta and small crater impacts, the site contains numerous boulders and rocks to the east, cliffs to the west, and depressions filled with aeolian bedforms (wind-derived ripples in sand that could trap a rover) in several locations.

The red dot on the map of Mars below shows this location. The blue dot is Gale Crater where Curiosity landed. The purple dot is the landing site for the European ExoMars rover. The yellow dot is where Opportunity has been roving, and the black dot is Spirit’s location.
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Sunset/sunrise on Mars

10:07 am

The sun on Mars's horizon

Cool image time! The image on the right, reduced to post here, was taken by Curiosity during a photo campaign this week to monitor Mars’s atmosphere. It looks out to the horizon at the Sun. I think the view is eastward, at Mount Sharp, as the Sun rises, but I am not sure. It might be looking west across the crater rim at sunset.

If you click on the image you can see it at full resolution. The haziness in the atmosphere might be left over from this summer’s global dust storm, but probably not, as I have read numerous reports in connection with Opportunity saying the storm is completely over and the atmosphere has now cleared. More likely it is from the windy conditions that are simply present these days at Gale Crater.

Regardless, it is quite cool because it illustrates how far we have come since the first planetary missions half a century ago. We can now routinely watch a sunset on Mars.

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Escape velocity on Phobos changes a lot depending on location

9:34 am

A new computer analysis of the shape of the gravitational field of the Martian moon Phobos suggests that the escape velocity varies significantly, depending on where you are on the moon’s surface.

Phobos is an odd duck among our solar system’s moons. It’s tiny (a fraction of a percent the size of our own moon) and is shaped like a potato; that weird shape draws gravity to different places, depending on where you are.

All these features make Phobos a challenge to travel on, researchers report in Advances in Space Research. In some places, moving any faster than 5 kilometers per hour would be enough to free you from the moon’s meager gravitational pull, sending you off into space where you’d likely be captured by Mars’s gravity and end up orbiting the Red Planet. The fastest you could travel anywhere on Phobos would be about 36 kilometers per hour, or a little faster than a golf cart, the team finds.

Obviously, this must be recognized for any mission trying to land and explore the moon.

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Volcanic rivers on Mars

12:53 pm

Granicus Valles

Cool image time! The photo on the right, cropped and reduced to post here, was part of the November image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO). If you click on the image you can see the full resolution picture.

The uncaptioned release webpage is dubbed “Faults in Granicus Valles.” The image itself only shows a small part of Granicus Valles, named after a river in Turkey, that flows down from the estern slopes of the giant volcano Elysium Mons. While far smaller than the four big Martian volcanoes in the Tharsis region to the east and near Marines Valles (which I highlight often), Elysium Mons still outshines anything on Earth at a height of almost 30,000 feet and a width of 150 miles. It sits at about the same northern latitude of Olympus Mons, but all by itself, rising up at the very northern edge of the transition zone between the southern highlands and the northern plains, with the vast Utopia Basin, the second deepest basin on Mars, to the west.

Overview of Elysium Mons and Granicus Valles

Granicus Valles itself is almost five hundred miles long. At its beginning it flows in a single straight fault, but once it enters the northern plains of Utopia Basin it begins to meander and break up into multiple tributaries. The MRO image above shows only a tiny portion in the northern plains, as illustrated by the white box in the overview map to the left.
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More Pits on Mars!

3:30 pm

Pits near Arsia Mons

Cool image time! In the November image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO) were three images, dubbed by me in the collage above as number one, number two, and number three, showing pits south of Arsia Mons, the southernmost volcano in the chain of three giant volcanoes to the east of Mars’s largest volcano, Olympus Mons, and to the west of the Marineris Valles valley.

Mars overview showing pit locations

The image on the right provides the geographical context of the three pits. They are all south of the volcano on the vast lava flow plains that surround it. The location of pits #1 and #2 is especially intriguing, on the east and west edges of what appears to be a large lava flow that had burst out from the volcano, leaving a large lava field covering a vast area several hundred miles across just to the south. You can also see a similar large lava field to the north of the volcano. Both fields appear to have been formed when lava poured through the breaks created by the fault that cuts through the volcano from the northeast to the southwest.
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The ExoMars 2020 landing site

10:23 am

ExoMars 2020 landing site

Last week the European Space Agency (ESA) announced the final chosen landing site for their 2020 ExoMars rover, a region called Oxia Planum.

Since then they have posted several detailed overview maps describing this region. The image on the right, reduced slightly to post here, shows the final two candidate elliptical landing sites in black, with Oxia Planum on the left. The caption for this image adds this tantalizing detail:

Both landing site candidates lie close to the transition between the cratered northern highlands and the southern lowlands of Mars. They lie just north of the equator, in a region with many channels cutting through from the southern highlands to the northern lowlands. As such, they preserve a rich record of geological history from the planet’s wetter past, billions of years ago.

To understand better what they mean by this, we need to zoom out.
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Europe picks landing site for its ExoMars 2020 rover

4:32 pm

The European Space Agency (ESA) has chosen the landing site for its ExoMars 2020 rover, a generally flat area with scattered craters dubbed Oxia Palum.

After over 4 years of careful study of HiRISE and more recently CaSSIS images Oxia Planum was chosen because scientists were convinced that its fine grained sediments, deposited during the ancient Noachian epoch were ideally suited for the Exobiology rover. With an enormous catchment area the sediments will have captured organics from a wide variety of environments over a long period of time, including areas where life may have existed. The fine sediments should also be ideal for the ExoMars drill – it aims to get to 2 metres depth.

Remote identification with the Mars Express and Mars Reconnaissance Orbiter Infrared spectrometers shows the presence of clays and other minerals giving clues to its aqueous history. A large group of scientists have been working on proposing, characterising and down selecting the sites, all of which had fascinating aspects, but Oxia Planum is the clear winner on both science and engineering constraints.

Based on my analysis of the last two candidate sites, I would guess that they also picked Oxia Planum because it is less spectacular, flatter, and thus poses less risk. It also means the images from there will be a bit more boring for the ordinary person.

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Mars rover update: November 8, 2018

10:08 am

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.
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Puzzling fractures on Mars

11:31 am

Fractures on Mars

Cool image time! Today the Mars Reconnaissance Orbiter (MRO) science team released another month’s worth of images from the spacecraft’s high resolution camera. The picture on the right, reduced in resolution to post here, was the first image that I took a close look at, and decided it was worth posting immediately. If you click on the image you can see the full resolution version.

This image lacks a caption, but the release webpage is titled “Fractured Crater Floor.” It shows several cross-crossing fissures, some wide enough for dust to gather within into sand dunes. The fractures themselves appear to be cutting across a bulging dome.

My first reaction was to wonder where the heck this crater was on Mars, how big was it, and how dominate were the fractures within its floor. The image itself does not answer any of these questions. The fractures could be filling the floor, or not, and the crater could be small or big. Moreover, its location might help explain the cause of the fractures.

To understand any of the images from MRO it is always important to zoom out to get some context.
» Read more

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SpaceX’s Tesla passes Mars’ orbit

8:54 am

Capitalism in space: The Tesla roadster that was put into solar orbit by the first Falcon Heavy launch in February has now successfully flown beyond Mars’ orbit.

The significance of this achievement is that this payload was put into solar orbit by a private company, using its own funds. The government had nothing to do with it.

For the entire history of the space age such a thing was considered absurd and impossible. You needed government to fund and build these big space projects. With this launch SpaceX and Elon Musk once again demonstrated how that accepted wisdom was bunk.

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NASA completes final parachute test for 2020 Mars rover mission

8:48 am

NASA has completed the third and final parachute test for its as yet unnamed 2020 Mars rover mission.

Three separate test launches (one Oct. 9, 2017, April 20, 2018, and Sept. 7, 2018) determined which parachute design would be used for the Mars 2020 mission. In 2012, a similar parachute concept was used for the Curiosity rover mission.

For this test, NASA said the parachute, which was made of nylon, Kevlar and Technora fibers, was packed into a “small drum-sized bag” before being launched to an altitude of about 23 miles (37 kilometers) and a speed of about Mach 1.8. Then, within less than a half-second, the 180-pound parachute was deployed and fully inflated with a volume of “a large house.”

Though doing engineering tests to prove your concept always makes sense, didn’t NASA do this for Curiosity, which then proved its parachute concept further by actually landing on Mars successfully? The 2020 rover is supposed to be saving money by using the Curiosity design. Why were these tests necessary?

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The vast northern plains of Mars

3:33 pm

The vast northern plains of Mars

Cool image time! Actually, this image, found in the October image release from the high resolution camera of Mars Reconnaissance Orbiter (MRO), is not that interesting, in its own right. Context is all!

The image on the right is a small section cropped and reduced in resolution from the full image, which you can see by clicking on it. It shows one of the only interesting features in this long image strip, a small mesa sticking out all by itself in a flat featureless plain pockmarked by various small craters.

The release has no caption, though it is entitled “Northern Plains Survey.” The northern plains, while having a lot of interesting features that attract the attention of planetary scientists and thus get photographed at high resolution, is mostly featureless, at least at the resolution of the wide field survey cameras on many Mars orbiters. In order to know what is really there, they need to take high resolution images systematically, of which this image is obviously a part.

Overview image

The problem is that there is so much ground to cover. This particular image was taken of a spot in the middle of the plains just to the north of the drainage outlets from Valles Marineris, as shown by the context map to the right. The tiny white spot to the right in the middle of the blue plains north of those drainage outlets is the location of this image.

Detail area of overview map

To understand how much ground needs to be covered, to the right is a close-up of the area shown by the white box in the first image above, with red rectangles indicating where MRO has already taken images. The white cross is the subject image. As you can see, most of this immense plain has not yet been imaged. It is almost as if they threw a dart to pick this one location. Most everything around it remains unseen at high resolution. Thus, to understand the geology of this one image is hampered because the surrounding terrain remains unknown, in close detail.

Mars is a big place. It is an entire planet, with the same land surface as the Earth’s continents. It still contains many mysteries and unexplored places. It will take generations to see it all.

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NASA decides to continue to ping Opportunity

9:10 am

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.

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The steep slumping wall of a Martian volcano caldera

10:19 am

Caldera wall

Cool image time. The Mars Reconnaissance Orbiter science team today released a nice captioned image of the steep wall of the caldera of Ascraeus Mons, the northernmost of the three giant volcanoes that lie to the east of Olympus Mons, the biggest volcano of all. The image on the right, reduced and cropped, shows that steep wall, with full image available by clicking on it. The caption from the release focuses on the fluted upper parts of the wall.

We can see chutes carved into the soft dust that has built up on the slope, with some similarities to gully landforms elsewhere on the planet.

More revealing to me is how this image reveals the slumping that is slowing eroding the caldera’s walls while also making that caldera larger. First, the plateau above the cliff shows multiple small cliffs and pit chains, all more or less parallel to the wall. This suggests that the plateau is over time breaking apart and falling into that caldera. Think of it as an avalanche in slow motion, with the upper plateau separating into chunks as sections slowly tilt down toward eventual collapse. As these chunks separate, they cause cracks to form in that plateau, and hence the parallel cliffs and strings of pits.

On the floor of the caldera we can see evidence of past chunks that did fall, piled up in a series terraces at the base of the wall. These are covered with the soft dust that dominates Martian geology. That soft dust also apparently comprises much of the wall’s materials, and almost acts like a liquid as it periodically flows down the wall, producing the chutes at the top of the wall.

The weak Martian gravity here is an important factor that we on Earth have difficulty understanding. It allows for a much steeper terrain, that also allows structurally weaker materials to hold together that would be impossible on Earth.This image gives a taste of this alien geology, on a large scale.

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Curiosity resumes science operations

9:50 am

Though NASA has yet to announce this officially, Curiosity’s science team has made it clear that they are in the process this week of resuming full science operations.

Today was the first day of planning with the full science team since Curiosity had an anomaly on sol 2172. It has been a over a month since we last looked at the “workspace,” the region in front of the rover that the arm can reach, and there were some surprises in store for us! Before the anomaly, the rock was covered with gray-colored tailings from our failed attempt to drill the “Inverness” target, as seen in the Mastcam image from sol 2170. In the new image above, however, those tailings are now gone – and so is a lot of the dark brown soil and reddish dust. So while Curiosity has been sitting still, the winds have been moving, sweeping the workspace clean.

Those operations can also be seen in the images the rover is sending down. For the first time in almost six weeks images are arriving daily, from multiple cameras, and in large numbers.

What we yet don’t have is a detailed description outlining why it took so long to get the second computer up and running, and what they are doing, if anything, to repair the computer that produced the problems last month.

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Scientists calculate Mars methane release

8:56 am

A new model describing how warmer weather could cause the seasonal spikes of methane on Mars matches the data from Curiosity in Gale Crater.

Moores and his colleagues analysed how methane might seep upwards through cracks and fissures in the Martian soil until it enters the atmosphere. Warming the soil could allow the gas to leak into the air, their calculations show. Seasons on Mars are complex, especially at Curiosity’s location so close to the planet’s equator. But the highest methane levels do appear just after the warmest time of the year, suggesting that heat spreading downward allows more of the gas to be released.

The amount of gas that the scientists estimate is entering the atmosphere is a good match for the measurements Curiosity has made at Gale crater, Moores told the American Astronomical Society’s Division for Planetary Sciences meeting in Knoxville, Tennessee. The methane’s ultimate source is still a mystery. But the work could help to explain the gas’s seasonal ebb and flow, he said. [emphasis mine]

The highlighted sentence is the most important. All they have done is found that they can model the pattern of seasonal release. They still have no idea whether the methane comes from a geological or biological source, which is of course the real question.

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Intriguing water-ice cloud on Mars

9:41 am

Water-ice cloud over Arsia Mons

An extended water-ice cloud has formed recently on the downwind side of the large Martian volcano Arsia Mons. The image above, cropped to post here, was taken by Europe’s Mars Express orbiter, and shows the cloud extending westward from the volcano.

In spite of its location, this atmospheric feature is not linked to volcanic activity but is rather a water ice cloud driven by the influence of the volcano’s leeward slope on the air flow – something that scientists call an orographic or lee cloud – and a regular phenomenon in this region.

The cloud can be seen in this view taken on 10 October by the Visual Monitoring Camera (VMC) on Mars Express – which has imaged it hundreds of times over the past few weeks – as the white, elongated feature extending 1500 km westward of Arsia Mons. As a comparison, the cone-shaped volcano has a diameter of about 250 km.

… Mars just experienced its northern hemisphere winter solstice on 16 October. In the months leading up to the solstice, most cloud activity disappears over big volcanoes like Arsia Mons; its summit is covered with clouds throughout the rest of the martian year.

However, a seasonally recurrent water ice cloud, like the one shown in this image, is known to form along the southwest flank of this volcano – it was previously observed by Mars Express and other missions in 2009, 2012 and 2015.

What the article does not mention about these seasonal water ice clouds is that they are thought to be related to the evidence of past glaciers on the volcano’s western slopes. Some scientists believe that significant underground ice, left over from those glaciers, is what causes the clouds.

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Changes on the slopes of Olympus Mons?

12:15 pm

Dark splotches on slopes of Olympus Mons

Cool image time! In reviewing the many images from the October image release from the high resolution camera on Mars Reconnaissance Orbiter (MRO), I came across two images, here and here, labeled “Change Detection in Olympus Maculae.” The image on the right is a cropped and reduced section of the first image, centered on the area of most interest. If you click on the image you can see the full photograph.

I did some research to see if I could find the changes indicated by this title. The location is an area on the outer western slopes of Olympus Mons, the largest volcano in the solar system. I found that MRO has taken images of this location twice before, in 2007, in 2009. I spent about fifteen minutes trying to find something that had changed, but was unable to locate anything, other than what look like a few wind-blown streaks probably caused by dust devils. I suspect I do not know what to look for.

Maybe my readers can spend some time and find these changes. If you do, please let us know in a comment.

Nonetheless, these two images revealed an area on the slopes of Olympus Mons that is most intriguing. It appears that there is a whole string of these dark splotches in this area, all of which have been carefully imaged by MRO several times. These splotches, along with the image titles, suggest that this might be area where there is activity from below that is causing the surface to darken. Could it be volcanic? Not likely. More likely is that there is underground frozen water located here, and like the spiders at the poles, this ice periodically pushes up as it sublimates to burst out as gas, and in the process darkens the surface.

If this guess on my part is correct, it suggests that this is an area in the mid-latitudes of Mars where water might be reasonably accessible. For future settlers this would be a significant discovery. And if my guess is wrong no matter. The features are puzzling, which explains why the scientists are aiming MRO at them repeatedly.

If I was to writing my science fiction novel Pioneer today, this is where I would have placed the discovery of the body of the Sanford Addiono, the astronaut who had disappeared on an asteroid near the orbit of Jupiter forty-six years previously. As the press release for the book’s release noted,

How Addiono had gotten to Mars from a distant lost asteroid–without a spaceship–was baffling.

That riddle was magnified by what Addiono had brought back with him. Among his effects was a six-fingered robot hand that had clearly been made by some alien civilization, along with a recorder and memo book describing what Addiono had seen.

What better place to put the start of this mystery but here, on a dark splotch on the slopes of Olympus Mons that also indicates its own geological mystery, a place some underground activity might be reshaping the surface of Mars.

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More successful image downloads for Curiosity

11:24 am

It increasingly looks like the computer download issues on the Mars rover Curiosity are being solved. For the first time in more than five weeks engineers were able to download numerous images from both of the rovers hazard avoidance cameras as well as both of its navigation cameras. More importantly, for the first time in five weeks they were able to do this two days in a row.

The Curiosity science team has as yet released no press update, but it appears that they are carefully testing the computer to make sure it is functioning properly. This computer was the rover’s original primary computer, but when it had problems several months after landing they had switched to the back-up computer. When that back-up computer had problems sending data back to Earth in September they decided to switch back to the original computer, which had been thought fixed.

Because of the original issues with the primary computer I suspect they are simply proceeding very slowly, so as not to have something fail in a manner that will not be recoverable. First they used it two weeks ago to upload a handful of small images from the hazard avoidance and navigation cameras. Then, after a week of analysis they uploaded a few more images from these cameras.

Then, after another week of analysis, they uploaded a full complement of images from all four cameras, and they did it two days in a row, suggesting that they are increasingly confident that the computer is operating correctly.

I expect a press release updating us on the specifics any time now.

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Active signaling to Opportunity to end

6:40 am

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.

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First interplanetary image from a cubesat

12:39 am

One of the two MarCO cubesats launched with the InSight Mars lander has successfully taken its first picture of Mars, the first such image ever taken by an interplanetary cubesat.

The image itself is not that interesting, with Mars not much more than a dot. What makes this significant is that it proves that a small, inexpensive cubesat can be built with the capability to accurately point and take photographs during an interplanetary mission. This means that the entire field of interplanetary probes is prime for major changes, shifting from big expensive and rarely launched spacecraft to small inexpensive cubesats launching frequently and it large numbers.

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Land of swiss cheese and spiders

12:04 pm

Swiss cheese on Martian south polar cap

Time for some cool images! In one of their periodic captioned releases of an interesting high resolution image, the Mars Reconnaissance Orbiter (MRO) science team this week released a picture of the strange “swiss cheese” terrain found throughout the Martian southern polar cap. (I have already highlighted in an early post the spiders that form in the south pole as the carbon dioxide evaporates.) The image to the right is a cropped section of that image, which you can see in its entirety if you click on it.

The South Polar residual cap is composed of carbon dioxide ice that persists through each Martian summer. However, it is constantly changing shape.

The slopes get more direct illumination at this polar location, so they warm up and sublimate, going directly from a solid state to a gaseous state. The gas then re-condenses as frost over flat areas, building new layers as the older layers are destroyed.

The captioned link above also included a link to a gif animation showing how this terrain has changed since 2009. The holes have become bigger, their cliffs retreating with time.

The section I highlight above not only shows the retreating swiss cheese dry ice, you can also see ghosts of several buried craters slowly becoming visible as the dry ice evaporates away.

This is only one of many images taken of the south pole by MRO. In the October archive release, I found almost two dozen, and that’s only the images taken during August of this summer. MRO takes images of the south pole regularly to track its changes, though I suspect it took more this summer because the global dust storm blocked imagery in the middle latitudes. Below and to the right is just one of these images, a particularly good illustration of the swiss cheese formation.
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Curiosity sends down images for the first time in weeks

9:28 am

Good news! For the first time since September 15 Curiosity has sent back images.

The last raw images were received on Sol 2171, equivalent to September 15. Today’s images (Sol 2199) from the front and rear hazard cameras and the two navigation cameras suggest that the engineers have solved the computer issues that prevented the rover from sending its science data to Earth.

No press release has yet been released, but I suspect we shall see something shortly.

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A vent on Mars?

1:29 pm

A vent on Mars?

Cool image time! In their exploration of the surface of Mars using Mars Reconnaissance Orbiter (MRO), scientists often image geological features that strongly resemble Earth features. Sometimes, if real, the resemblances are significant, as they indicate important geological activity on Mars that can tell us a lot about the conditions and environment there.

The image on the right, cropped and reduced in resolution to post here, is a good example of this. It was taken by MRO on June 14, 2018, just before the global dust storm obscured the planet’s middle latitudes for most of the summer, and was part of the monthly release of new images from the spacecraft. (If you click on the image you can see the full resolution picture.) The release website, which includes no caption, describes this feature as an “apparent vent,” a determination that certainly seems reasonable. The shadowed dark features suggest an abrupt oblong pit near the edge of a cliff, formed in the center of a collapsed sink. The tear-drop shape of the collapse sink and surrounding darkened areas also suggests that something is venting from it and then blowing away to the east and south, forming the darker stained ground. Some of the dark features to the southeast might also be smaller vents, releasing their own materials into the atmosphere.

The location also reinforces this suggestion, located on the southeast lava slopes of one of Mars’ larger volcanoes, Elysium Mons. This is also a region, dubbed Athabasca Valles, that some planetary scientists believe is one of the youngest lava flows on Mars.

Finally, it appears that the pit here has darkened considerably recently. MRO has taken images of this pit twice previously, in 2008 and 2010, and in both images the pit is much lighter in color, with its sandy dune-covered floor much easier to see. In the new image the floor is now very dark. This might be caused by shadows and the angle of the Sun, but I don’t believe so. It is also clear when comparing all three images that the surrounding area, including the flow to the southeast, has also darkened with time.

All this data suggests that the pit is venting something into the air, and it is settling on the ground to the southeast, blown there by the prevailing winds. Nor is this pit the only such feature in this region. Other images by MRO show a lot of similar dark splotches.

The problem is that this feature is not on Earth but on Mars. Determining what is being vented, and why, is therefore made more difficult. Based on Earth data you would assume this is some form of volcanic vent, releasing gases from below the surface. On Mars that assumption might not hold. We might instead be seeing the venting of any number of possible materials, such as underground water-ice, carrying with it other underground materials and thus darkening the surface.

We also can’t assume that the venting is occurring because of volcanic processes. On Mars the evidence so far gathered suggests that active volcanic activity ceased a very long time ago, even for this very young lava region. The venting is likely caused by something else, a fact that in itself is probably the most significant take-away from these images.

Something appears to be causing an active vent on the surface of Mars. Finding out the root cause of that venting is probably one of the more interesting questions facing researchers who study the Martian surface.

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Curiosity to switch computers in effort to restore operations

10:44 pm

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.

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Mars Reconnaissance Orbiter spots Opportunity through dust

3:41 pm

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.

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Curiosity has problem sending back its stored data

9:10 am

The science team running Curiosity found this week that the rover is suddenly unable to send back its stored data.

Over the past few days, engineers here at JPL have been working to address an issue on Curiosity that is preventing it from sending much of the science and engineering data stored in its memory. The rover remains in its normal mode and is otherwise healthy and responsive.

The issue first appeared Saturday night while Curiosity was running through the weekend plan. Besides transmitting data recorded in its memory, the rover can transmit “real-time” data when it links to a relay orbiter or Deep Space Network antenna. These real-time data are transmitting normally, and include various details about the rover’s status. Engineers are expanding the details the rover transmits in these real-time data to better diagnose the issue. Because the amount of data coming down is limited, it might take some time for the engineering team to diagnose the problem.

On Monday and Tuesday, engineers discussed which real-time details would be the most useful to have. They also commanded the rover to turn off science instruments that were still on, since their data are not being stored. They’re also preparing to use the rover’s backup computer in case they need to use it to diagnose the primary computer. That backup computer was the rover’s primary one until Sol 200, when it experienced both a hardware failure and software issue that have since been addressed.

In other words, the rover is functioning, they can communicate with it in real time, but any data stored on board for some reason is not being transmitted.

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New data says going to Mars involves significant radiation exposure

9:18 am

New data from Trace Gas Orbiter, part of Europe’s ExoMars project, says a journey to Mars will expose humans to significant radiation.

The results imply that on a six-month journey to the Red Planet, and assuming six-months back again, an astronaut could be exposed to at least 60% of the total radiation dose limit recommended for their entire career.

The ExoMars data, which is in good agreement with data from Mars Science Laboratory’s cruise to Mars in 2011–2012 and with other particle detectors currently in space – taking into account the different solar conditions – will be used to verify radiation environment models and assessments of the radiation risk to the crewmembers of future exploration missions.

This data was gathered during the spacecraft’s journey to Mars during a time of falling solar activity. Thus, the radiation exposure came more from cosmic rays than from solar activity.

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