Tag Archives: Mars Express

Mars Express confirms ancient glaciers in northern Martian mid-latitudes

Perspective view of Deuteronilus Mensae
Click for full image.

The European Space Agency’s orbiter Mars Express has confirmed the presence of large fractured ice sheets suggestive of buried and ancient glaciers. These ice sheets are within one region on Mars located in the mid-latitudes where many such glacial features have been found. They are also in the transition zone between the northern lowlands and the southern highlands.

This landscape shows clear and widespread signs of significant, lasting erosion. As is common with fretted terrain, it contains a mix of cliffs, canyons, scarps, steep-sided and flat-topped mounds (mesa), furrows, fractured ridges and more, a selection of which can be seen dotted across the frame.

These features were created as flowing material dissected the area, cutting through the existing landscape and carving out a web of winding channels. In the case of Deuteronilus Mensae, flowing ice is the most likely culprit. Scientists believe that this terrain has experienced extensive past glacial activity across numerous martian epochs.

It is thought that glaciers slowly but surely ate away at the plains and plateaus that once covered this region, leaving only a scattering of steep, flat, isolated mounds of rock in their wake.

Smooth deposits cover the floor itself, some marked with flow patterns from material slowly moving downhill – a mix of ice and accumulated debris that came together to form and feed viscous, moving flows of mass somewhat akin to a landslide or mudflow here on Earth.

Studies of this region by NASA’s Mars Reconnaissance Orbiter [MRO] have shown that most of the features seen here do indeed contain high levels of water ice. Estimates place the ice content of some glacial features in the region at up to 90%. This suggests that, rather than hosting individual or occasional icy pockets and glaciers, Deuteronilus Mensae may actually represent the remnants of an old regional ice sheet. This ice sheet may once have covered the entire area, lying atop the plateaus and plains. As the martian climate changed this ice began to shift around and disappear, slowly revealing the rock beneath.

Overall, the data coming from both Mars Express and MRO increasingly suggests that there is a lot of buried glacial ice in the mid-latitudes. Mars might be a desert, but it is increasingly beginning to look like much of the planet is a desert like Antarctica, not the Sahara.

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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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Mars Express looks at Martian river relic

Mars Express perspective view of Nirgal Vallis
Click for full image.

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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The glaciers of Mars

The glaciers on Mars

For the future colonists of Mars, the question of finding water will not be that much of a problem. Not only have planetary geologists mapped out the existence of extensive water-ice in the Martian poles, they have found that the planet apparently has widespread glacier deposits in two mid-latitude belts from 30 to 60 degrees latitude.

The question will be whether those Martian settlers will be able to easily access this water. The data so far suggests that much of the Martian underground water at high latitudes is likely mixed with dust and debris. Extracting it might not be straightforward. There are hints that the ice table at latitudes about 55 degrees might be more pure, but could be somewhat deep below ground, requiring the settlers to become miners to obtain their water. Moreover, all these high latitude locations are in environments that are more hostile, and therefore more difficult to establish a colony.

What about the glaciers? The global map of Mars above, reduced and annotated to post here, shows what are believed to be extensive glacial deposits at lower latitudes, and comes from a recently published paper on the subject. The different colors indicate the different types of glacial deposits the scientists have identified.

Green and yellow indicate what scientists call lineated valley fill (LVF) and lobate debris aprons (LDA) respectively, glacial deposits found in the transition zone between the southern highlands and either the northern lowland plains or the basins of the southern hemisphere, Hellas and Argyre. These glaciers are in many ways most similar to glaciers found on Earth, flows heading downhill along natural geographic features.

Magenta represents concentric crater fill (CCF), glacier features which seem very evenly distributed across both the northern and southern lower mid-latitude belts. Here scientists appear to have detected buried ice within the floors of craters.

The paper which included this map focused on describing a new glacial feature, something they dubbed valley fill deposits (VFD), that they had found so far in only one place, as indicated by the black square on the map.

The photograph below and on the right, reduced and cropped to post here, is from figure two of the linked paper.
» Read more

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Chaos on Mars

Aurorae Chaos in Margaritifer Terra
Click for full image.

The Mars Express science team today released a digital perspective view of the chaos terrain located in the outlet region for the vast drainages, which include Marineris Valles, coming down from the Tharsis Bulge volcanic region that holds Mars’ largest volcanos.

The view, reduced to post here on the right, was created from a image taken by Mars Express on October 31, 2018. This chaos terrain is south of the various examples of chaos terrain previously highlighted here on Behind the Black (May 14, 2018, June 26, 2018, March 11, 2019, March 14, 2019). As they note,

The division between the chaotic terrain and plains can also be seen clearly in these images. The left (south) side of the image is notably smoother and more featureless than the jumbled right (north) side, and the two regions are split by a prominent line carving diagonally across the frame. The transition area around this scarp is especially broken and fractured; this is thought to be caused as the martian crust stretched and moved.


The ancient chaotic terrain we see on Mars holds information about how water once permeated and interacted with the planetary surface, including how it was transported, stored, and released.

Chaotic terrain is thought to have formed as chunks of the martian surface collapsed in dramatic events triggered by the heating of material containing ice or water-bearing minerals – possibly due to climatic or volcanic heat sources, or an impact from an asteroid or comet. This released large amounts of water, causing the terrain above to subside. The water then drained away quickly, leaving behind the messy, broken patterns seen in regions such as Aurorae Chaos, which is thought to have formed some 3.5 billion years ago.

Mars Express images don’t quite have the resolution of the high resolution images from Mars Reconnaissance Orbiter, but they cover a wider area, so that the spacecraft has now photographed almost the entire Martian surface since its arrival in Mars orbit in December 2003.

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Liquid water found beneath Martian south pole

Data from Europe’s Mars Express orbiter has detected a pond of liquid water buried beneath the Martian south pole.

The radar investigation shows that south polar region of Mars is made of many layers of ice and dust down to a depth of about 1.5 km in the 200 km-wide area analysed in this study. A particularly bright radar reflection underneath the layered deposits is identified within a 20 km-wide zone.

Analysing the properties of the reflected radar signals and considering the composition of the layered deposits and expected temperature profile below the surface, the scientists interpret the bright feature as an interface between the ice and a stable body of liquid water, which could be laden with salty, saturated sediments. For MARSIS to be able to detect such a patch of water, it would need to be at least several tens of centimetres thick.

The data here is somewhat uncertain, but is also not to be dismissed. It is very likely this is liquid water.

I must add that this is not really a big surprise. Many scientists expected this. Also, this water is not very accessible, and is also located at the pole, the Mars’s harshest environment. Just because it is liquid is not a reason to aim to mine it. There is plenty of evidence of ice in much more accessible and reasonable locations.

What this discovery suggests is that it is possible to have liquid water on Mars. The great geological mystery of the planet is while that much of its geology appears formed by flowing water, scientists have not been able to devise good climate histories that make that flowing water possible. This discovery helps those scientists in devising those histories.

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Is it a volcano or an impact crater? Mars Express wants to know!

Europe’s Mars Express orbiter has taken a high resolution image of Ismenia Patera, a very large crater located in the Arabia Terra region of Mars, the largest part of the transition zone between the low flat northern plains and the high rough southern terrain.

The crater is intriguing to scientists because they are not sure if it was created by an impact, or a volcano.

Certain properties of the surface features seen in Arabia Terra suggest a volcanic origin: for example, their irregular shapes, low topographic relief, their relatively uplifted rims and apparent lack of ejected material that would usually be present around an impact crater.

However, some of these features and irregular shapes could also be present in impact craters that have simply evolved and interacted with their environment in particular ways over time.

There is also additional evidence that this region was once home to volcanic activity. If so, that activity would have changed the terrain, and thus made its geological history more complex and difficult to decipher, a fact that is important since this is also a region that might have been at the edge of theorized northern Martian Ocean.

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More evidence of giant flash floods on Mars

Mangala Valles

A newly released image from ESA’s Mars Express orbiter shows that catastrophic flooding — caused by ice melted from volcanic activity — created the Mangala Valles channels on Mars.

The perspective image on the right shows the topography of the region, with low points indicated in blue and high points by red. The channel along the right side of the image is Mangala Valles itself, though you can also see additional flood channels to the left of it passing around and through a large crater whose floor now stands above the surrounding terrain caused by the erosion of the rim plus the deposit of sediment inside the crater during the flooding.

I have a soft spot for Mangala Valles. When it was first photographed by the first orbiter missions to Mars in the early 1970s I was struck by its river-like appearance and striking topography. I therefore placed my Martian colony here in one of my efforts at science fiction writing. I figured it a good location for colonization, as there would likely be water and, by roofing over the deep canyon, a colony could be built relatively easily.

Better locations on Mars have since been found, but the location still intrigues me.

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Mars Express will do an extremely close flyby of the martian moon Phobos on December 29.

Mars Express will do an extremely close flyby of the martian moon Phobos on December 29.

Late this month, ESA’s Mars Express will make the closest flyby yet of the Red Planet’s largest moon Phobos, skimming past at only 45 km [28 miles] above its surface. The flyby on 29 December will be so close and fast that Mars Express will not be able to take any images, but instead it will yield the most accurate details yet of the moon’s gravitational field and, in turn, provide new details of its internal structure.

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In celebration of its tenth year in orbit, scientists running the Mars Express mission have released global mineral maps of Mars.

In celebration of its tenth year in orbit, scientists running the Mars Express mission have released global mineral maps of Mars. With video.

The unique atlas comprises a series of maps showing the distribution of minerals formed in water, by volcanic activity, and by weathering to create the dust that makes Mars red. They create a global context for the dominant geological processes that sculpted the planet we see today.

Take a look at the video. It is fascinating to see where these minerals concentrate.

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Mars Express has found more evidence that Mars once had oceans.

Mars Express has found more evidence that Mars once had oceans.

Two oceans have been proposed: 4 billion years ago, when warmer conditions prevailed, and also 3 billion years ago when subsurface ice melted following a large impact, creating outflow channels that drained the water into areas of low elevation.

“MARSIS penetrates deep into the ground, revealing the first 60–80 metres of the planet’s subsurface,” says Wlodek Kofman, leader of the radar team at IPAG. “Throughout all of this depth, we see the evidence for sedimentary material and ice.” The sediments revealed by MARSIS are areas of low radar reflectivity. Such sediments are typically low-density granular materials that have been eroded away by water and carried to their final destination.

This later ocean would however have been temporary. Within a million years or less, Dr Mouginot estimates, the water would have either frozen back in place and been preserved underground again, or turned into vapour and lifted gradually into the atmosphere. “I don’t think it could have stayed as an ocean long enough for life to form.”

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Mountains and buried ice on Mars

Mountains and buried ice on Mars.

New images from the high-resolution stereo camera on ESA’s Mars Express orbiter allow a closer inspection [of the Phlegra Montes mountain range] and show that almost every mountain is surrounded by ‘lobate debris aprons’ – curved features typically observed around plateaus and mountains at these latitudes. Previous studies have shown that this material appears to have moved down the mountain slopes over time, and looks similar to the debris found covering glaciers here on Earth.

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Mars Express takes a close look at the Mars volcano Tharsis Tholus

Mars Express takes a close look at one of Mars’ giant volcanoes, Tharsis Tholus.

At least two large sections have collapsed around its eastern and western flanks during its four-billion-year history and these catastrophes are now visible as scarps up to several kilometers high. The main feature of Tharsis Tholus is, however, the caldera in its center. It has an almost circular outline, about 32 x 34 km, and is ringed by faults that have allowed the caldera floor to subside by as much as 2.7 km.

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Mars atmosphere has more water vapor than predicted

Data from Mars Express has found that the Martian upper atmosphere has far more water vapor than predicted.

“The vertical distribution of water vapour is a key factor in the study of Mars’ hydrological cycle, and the old paradigm that it is mainly controlled by saturation physics now needs to be revised,” said Luca Maltagliati [of the Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS) in Guyancourt, France]. “Our finding has major implications for understanding the planet’s global climate and the transport of water from one hemisphere to the other.”

“The data suggest that much more water vapour is being carried high enough in the atmosphere to be affected by photodissociation,” added Franck Montmessin, also from LATMOS, who is the Principal Investigator for SPICAM and a co-author of the paper. “Solar radiation can split the water molecules into oxygen and hydrogen atoms, which can then escape into space. This has implications for the rate at which water has been lost from the planet and for the long-term evolution of the Martian surface and atmosphere.”

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