Tag: Mars

Craters in the soft Martian northern lowland plains

12:25 pm

Craters in the soft Martian northern lowland plains
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Cool image time! The photo to the right, cropped and reduced to post here, was a featured image today from the high resolution camera on Mars Reconnaissance Orbiter (MRO).

The caption, written by Carol Weitz of the Planetary Science Institute in Arizona, focused on the wind patterns created within these craters.

These impact craters in the northern middle latitudes have interesting interiors: all of them have wind-blown (aeolian) ripples.

Outside of the craters and along the crater floors, the ripples are all oriented in the same direction. However, along the walls of some of the larger craters, the ripples are situated radially away from the center, indicating the winds moving inside the larger craters can be influenced by the topography of the crater wall.

Additionally, many of the larger craters have layered mesas along their floors that are likely sedimentary deposits laid down after the craters formed but prior to the development of the aeolian ripples.

I am further intrigued by the rimless nature of these craters, as well as the lack of significant rocky debris at their edges. They all look like the bolides that created them impacted into a relatively soft surface that, rather than break up into rocks and boulders, melted, flowed, and then quickly refroze into these depressions.

The location, as always, provides us a possible explanation.
» Read more

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Zhurong’s continuing travels on Mars

10:26 am

Zhurong overview map
Click for original map.

This past week the Chinese press released a new but limited update on the status of both its Mars orbiter Tianwen-1 and its Mars rover Zhurong.

The map to the right uses as its background a high resolution picture from Mars Reconnaissance Orbiter. I have superimposed Zhurong’s route in green. You can get an idea of how far the rover has traveled since resuming communications with Earth in late October by comparing this map with the one I posted then. After stopping at a small sand dune (the crescent-shaped white features), it curved around to head to the southeast towards a rough area and a trough that is thought to be filled with sediment.

Meanwhile, the orbiter has shifted its orbit, changing from one dedicated mainly as providing a communications relay between Zhurong and Earth to one that now allows it to begin a two-year photographic survey of Mars.

To supplement the resulting gaps in communications for Zhurong, China and the European Space Agency (ESA) have made their first test using ESA’s Mars Express satellite as a relay satellite. Both hope to know soon whether it worked.

In either case, Zhurong’s travels will likely be slowed somewhat due to the reduction in communications access.

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Snow on Martian dunes

12:58 pm

Snowy dunes near the Martian north pole
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Close-up of snowy dunes
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Cool image time! The first photo to the right, rotated, cropped, and reduced to post here, was taken on September 19, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and shows what appears to be snow nestled in the hollows of many dunes.

The second photo, cropped to post here, shows in high resolution the area in the white box.

Is that snow water, or dry ice? The location is very far north, 76 degrees latitude, so it could be either. Since the photo was requested by Candice Hansen of the Planetary Science Institute in Arizona, I emailed her to ask. Her answer:

Early in the spring all the bright stuff is dry ice. As it gets later in the spring it is probably still mostly dry ice but with HiRISE images alone we cannot really distinguish the composition of the ice. In-between the dunes it is almost certainly bare ground late in the spring, but since the dunes are dark the surface just looks bright in contrast

This picture was taken in summer, which suggests the snow is probably water, not dry ice. Yet, all the snow is found in the north-facing hollows, places that will remain mostly in shadow at this high latitude, 76 degrees north. Thus, it is possible that the snow is the last remaining traces of the thin dry ice mantle that covers the Martian poles down to about 60 degrees latitude during the winter, and sublimates away in summer.

Hansen had requested a whole bunch of similar images of such snowy dunes. As she explained,
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A volcanic extrusion on the floor of Valles Marineris?

2:52 pm

A volcanic extrusion on the floor of Valles Marineris?
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 31, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the science team labels a “possible contact between two units.”

I think that contact is the point where that eroded mountain touches the surrounding smooth canyon floor. The mountain itself looks to me to be a very eroded extrusion of lava that was placed there from below a very very long time ago, covered later by material, and now exposed for a long enough period that its surface appears to have been carved by wind and even possibly flowing water or ice.

Because it is lava it is more resistant to erosion, which is why it sits higher than the smooth terrain around it. Even though both experienced the same processes of wear over time, the mountain’s surface was only carved away partly, while the material that had been in the floor was washed away entirely.

This is all a guess. However, a look below at the overview map, showing this mountain’s location on Mars, as well as MRO’s wider view from its context camera, I think strengthens my hypothesis.
» Read more

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Frozen lake bed in the Martian high latitudes?

2:03 pm

Frozen lakebed in the Martian high latitudes?
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Today’s cool image comes from today’s Mars Reconnaissance Orbiter’s (MRO) high resolution picture of the day, rotated and cropped to post here. The original was taken back on March 28, 2017.

What formed those strange circular ridges and the many small cracks and hollows? The caption provided is somewhat vague and I think confusing:

This formation looks like a crater from a meteor impact rather than an ancient caldera of a volcano. Connected to the crater is a carved-out area that resembles a lake bed. At high resolution, we might be able to determine the likelihood of a water lake bed or lava bed. This observation will give insight into some of the interesting geology of this area.

The crater this caption is referring to is not visible in the image provided. It can be seen to the west of this location, in the MRO context camera picture below.
» Read more

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Curiosity: Approaching the saddle

9:21 am

The saddle ahead
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Cool image time! The photo to the right, reduced to post here, was taken on November 5, 2021 by Curiosity’s high resolution camera, and looks forward at its planned route up onto the saddle ahead, where the rover will turn right and climb up into Maria Gordon Notch. (See this October post for a map outlining the rover’s future travels.) I think that cliff face is between 40 to 60 feet high, though this is a very wild guess.

As noted by Abigail Fraeman of JPL on the Curiosity blog on November 3, 2021,

The terrain is beginning to steepen as Curiosity gets close to the end of this region, so even though we’re only a few drives away from our last drill site … we’ve already climbed 25 m higher!

The route ahead looks equally steep, though the ground actually appears less rough, with fewer large jagged boulders that Curiosity must avoid to protect its wheels.

It will likely be at least one to three weeks however before Curiosity gets to that saddle. The science team has begun a drilling campaign at the present location, and this will take time, depending on how many holes they decide to drill.

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Ingenuity completes 15th flight

9:04 am

Ingenuity landing on November 6th
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No details have been released, but based on the latest raw images downloaded from the Mars rover Perseverance today, the helicopter Ingenuity successfully completed its 15th flight in Jezero Crater yesterday.

The image to the right is the last of five released this morning, showing the helicopter’s shadow on the ground, just before Ingenuity touched down. Note how the shadow of Ingenuity’s four legs appear oriented level relative to the ground. While the first of the five images shows the shadow tilted, as if the helicopter is making a last turn, the last four photos all show the legs oriented properly.

We will have to wait now for official confirmation.

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Ingenuity next flight will begin route retracing its path

9:20 am

Overview map

The Ingenuity engineering team has revealed that the helicopter’s 15th flight on Mars will have it begin retracing its steps, following approximately the same flight route as it heads back towards Perseverance’s landing site in Jezero Crater.

Flight #15 is the start of our journey back to Wright Brothers Field [the helicopter’s initial flight test area just north of the landing site]. Taking place no earlier than Saturday, Nov. 6 at 9:22 a.m. PT, or 12:03 LMST (local Mars time), the 254th sol (Martian day) of the Perseverance mission, Flight #15 will return Ingenuity back to the Raised Ridges region, imaged in Flight #10. In this flight the helicopter will traverse 1,332 feet (406 meters) during 130 seconds of flight, travelling at 11.1 mph (5 mps) groundspeed. We’ll capture color return-to-earth (RTE) high resolution (13MP) images, one post-takeoff pointed to the SW, and nine pointed toward the NW along the flight-path. Nominal altitude for the flight is expected to be 39.3 feet (12 meters) above ground level.

This will be the second flight of Ingenuity during Mars’ summer low air-density, requiring that the rotor blades are spun at 2,700 RPM to compensate. This flight will generate critical high-RPM motor performance, which the team will use to design and tailor upcoming low-density flights in the months ahead.

Perseverance is presently sitting in an area they have dubbed Seitah, a region the rover skirted around to get to this point. I had hoped both the helicopter and rover would return to the north cutting across Seitah and thus scout out new terrain. Instead, it appears that both the rover and helicopter will return as initially planned, traveling over the same ground both took to get where they are today.

In other words, the teams have decided to take the safest route, though it will provide them much less new science data. While this might seem prudent, it really appears overly cautious, based on the capabilities of Perseverance and the roughness of the terrain in Seitah. Curiosity is presently traveling across far more difficult terrain in the mountains at the foot of Mt Sharp, and it is doing so with wheels that are damaged and not as well designed as Perseverance’s. Not roving in uncharted terrain seems a waste of Perseverance’s capabilities.

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The strange surface of Mars’ north pole icecap

1:02 pm

Mars' north pole icecap
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Cool image time! The photo to the right, rotated, cropped, and annotated to post here, was taken on September 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows us a very small section of Mars’ north pole icecap.

What are we looking at? The picture was taken in summer, so by this point the thin mantle of dry ice that falls as snow in the winter and covers the north pole down to about 60 degrees latitude has sublimated away. This surface thus is water ice interspersed with Martian dust.

Yet, unlike the Antarctic icecap on Earth, the ice surface is not smooth and flat. Instead, this Martian ice has a surface that is a complex arrangement of hollows and ridges, all about the same size. Why?

And what are the two larger white spots? What caused them and why are they the only differently-sized objects in the picture?

The full resolution close-up, found at the image website, provides some answers to these questions.
» Read more

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Two skylights into connected Martian lava tube?

3:33 pm

Two skylights into a connected Martian lava tube?
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Cool image time! The photo to the right, cropped and annotated to post here, was taken on September 1, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). I have annotated it to note the two apparent skylights that appear aligned along a north-south depression.

The grade is downhill to the north. If you look at the full image you will see that this north-south depression extends for a considerable distance beyond the edges of the cropped image above, with that depression appearing to dissipate to the north into a series of parallel very shallow depressions, almost like the lava had flowed out of the tube and formed branching surface rivulets heading south.

The overview map shows that this tube is on the northern flanks of the volcano Arsia Mons.
» Read more

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Curiosity looks back across the alien landscape of Mars

12:45 pm

Gale Crater, October 31, 2021
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Cool image time! The photo above, the first of 21 identical images taken by Curiosity’s right navigation camera, taken at intervals of about thirteen seconds on October 31st, was probably snapped as part of an effort to spot a moving dust devil. At the resolution available to my software, I see nothing when I compare all 21 photos.

What I do see is a remarkably alien landscape. In the distance can be seen the mountains that mark the rim of Gale Crater, 30-plus miles away. On the image’s right edge you can see the rising slope heading up to the peak of Mount Sharp about 13,000 feet higher.

In the center are those blobby mesas that make this terrain look so strange. For the past decade Curiosity has been traveling from the floor of the crater on the picture’s far left to circle around that dark sand dune sea to climb up the mountain slopes in the foreground in front of those mesas.

It is now heading to the right, into the mountains that make up Mount Sharp. Such a view of the floor of Gale Crater will thus be for the next few years more difficult to catch, as the mountains themselves will block the view. Assuming the rover survives long enough, it will have to climb much higher before it can get such an expansive view again.

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Holes in snowy ice on Mars?

1:30 pm

Holes in snowy ice on Mars?
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Cool image time! Today we return to the regions surrounding Milankovic Crater in the high northern latitudes of Mars. The photo to the right, cropped and reduced to post here, was taken on June 1, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a spray of impact craters where the bolides apparently landed in relatively soft material. The location itself is about 10 miles to the southeast of the 74-mile-wide crater, and sits within its rim ejecta blanket.

The label for the image says this is showing “crater modification,” which suggests that the rimless nature of these craters became so after their creation. This location, at 54 north latitude, is in a region of Mars where scientists have found a lot of evidence of near surface ice. For example, within Mikankovic Crater itself they have identified numerous scarps with clearly seen pure ice layers.

If ice is close to the surface here, then the ground could be like soft snow on Earth, especially because Mars’ lighter gravity would not compress that ice as much. Think about what happens when you toss pebbles into soft snow. They fall through, and leave behind holes not unlike the ones we see in this picture. Later, sunlight would begin to modify the holes so that their edges grow outward, once again exactly as we see here.

The overview map below as always gives some context, which in this case has less to do with Mars but with Elon Musk and Starship.
» Read more

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One last look at a Martian mountaintop

9:14 am

Siccar Point
For the original images go here and here.

The image above is a mosaic made from two Curiosity navigation photos taken on October 23, 2021 and combined, cropped, and reduced to post here. It shows the top 30 feet or so of Siccar Point, the spectacular outcrop that I have featured several times previously.

Curiosity has now traveled past this outcrop, so that this view above is no longer visible to the rover. I post it now as a farewell image of what I think is the most breath-taking feature yet seen by any planetary lander — manned or unmanned — since the first set down on the Moon in the mid-1960s. It also illustrates with great clarity the alien nature of Mars. Those delicate overhanging rocks would not be possible on Earth, with a gravity about two and a half times heavier than Mars.

Note too that I have not enhanced the contrast or brightness. I think the twilight light here actually gives us a sense of the real brightness of a clear Martian day. Because the Sun is much farther away, even at high noon it provides much less illumination than on Earth. A bright day on Mars to our Earth-adapted eyes will always feel like dusk.

Meanwhile the science team is quickly pushing the rover south, to get…

…closer to the area we are targeting for our next drill campaign. This drive should leave us with bedrock in the workspace for additional contact science on the weekend. This terrain continues to be very challenging, with large boulders, sharp rocks that are wheel hazards, and sand ripples, like the terrain shown in the image. These drives take a while to plan to make sure we are avoiding all the hazards while getting to where science wants to go. Our paths end up looking a little “drunk” as we weave our way around obstacles.

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Curiosity marches on into the mountains

1:09 pm

Curiosity marches onward to Maria Gordon Notch
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Overview map
Click for interactive map

With the end of the solar conjunction in the first half of October, blocking communications with Mars because the Sun was in the way, Curiosity has resumed its travels. It has moved past the spectacular outcrop I have highlighted previously, an outcrop the science team has labeled Siccar Point.

They are now moving south at the base of the cliff to the west, the top of which is a plateau they call the Greenheugh Pediment, heading for a gap where the rover will be able to turn right and head up onto that pediment. The red dotted line on the overview map to the right shows this route, which corresponds to the red dotted line on the photo above.

I estimate the cliffs on both sides of Maria Gordon Notch are about 100 feet high. The notch itself I estimate is about 750 feet away. At the pace Curiosity has been traveling across this rough ground, it could probably reach it in about two to three weeks. However, I expect the science team will stop at least once along the way to do more detailed science work, so that journey might take a month or slightly more.

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Ingenuity completes 14th flight on Mars

11:31 pm

Ingenuity's shadow below it during 14th flight
Ingenuity’s shadow below it during 14th flight.
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On October 24th, Ingenuity successfully completed its 14th flight on Mars, a short test hop up and down to see if the helicopter could function properly as the air pressure in the Martian atmosphere drops due to seasonal variations.

As planned, the helicopter executed its first 2,700 rpm flight, proving that Ingenuity is capable of flying in the weeks and months ahead on Mars, during which seasonal changes on the surface will result in decreases in air density. The short 23-second flight included a peak altitude of 16 feet (5 meters) above ground level, with a small sideways translation of 7 feet (2 meters) to avoid a nearby sand ripple.

I predict the next flight will head north, leap-frogging past Perseverance to get a better view of the South Seitah area so that the rover team can decide whether they can continue north through that terrain or retreat backwards.

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China resumes communications with Zhurong Mars rover

10:13 am

Elevation map of Zhurong location
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The new colonial movement: China yesterday announced that it has regained communications with its Zhurong rover, located in the Martian northern lowland plains of Utopia Planitia.

The image to the right, cropped and annotated by me to post here, is a digital terrain map created from two high resolution photos taken by Mars Reconnaissance Orbiter (MRO). The black line shows the route Zhurong has traveled since landing in May.

According to [Chen Baichao, the chief designer of Zhurong], the rover has traveled more than 1,000 meters since it landed on Mars at the southern part of Utopia Planitia in May 2021. After the solar conjunction, it will head south to find mud volcanoes, which scientists are interested in, located about 10 km away.

American scientists had hoped Zhurong would head north to a much larger mud cone that was much closer. Their decision to head south to the smaller cones farther away tells us that they have given themselves a much more challenging mission. It also suggests they decided it will be easier to get Zhurong closer to a smaller cone.

Based on that 10 kilometer distance, it seems the Chinese are aiming for the cones near the bottom of the map. It took Zhurong three months to travel the distance shown. At that pace, to get to those small southern mud cones will likely take, at a minimum, about fifteen months. Though the ground is quite flat, the rover will either have to negotiate one small rise of about 15 feet, or detour to the east somewhat to find a less steep route.

It is also possible that they will instead head to the mud cone south of the large impact crater. It is also a small cone, is much nearer, and will not require them to get past that rise.

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Layered glaciers in Mars’ glacier country

3:48 pm

Layered glacier in Mars' glacier country
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Cool image time. The photo to the right, cropped and reduced to post here, was taken on August 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows two different impact craters in a glacial region dubbed Nilosyrtis Mensae, located in the northern mid-latitudes in the 2,000 mile long strip chaos terrain that I have labeled glacier country because practically every image finds them there.

The splash apron surrounding the larger crater is typical of craters in Martian regions where ice is thought to be near the surface.

What makes this picture interesting is that the glaciers appear layered. You can see evidence of this in the mounds inside both craters. Those mounds appear to represent earlier periods when there was more ice here. Since then the mounds have partly sublimated away.

You can also see evidence of layers in the material surrounding the nearby larger mounds.

The map below shows us where this image is, relative to all of glacier country as well as the rover Perseverance in Jezero Crater.
» Read more

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China resumes communications with Tianwen-1 Mars orbiter

8:45 am

With the Sun no longer between the Earth and Mars, China has re-established communications with its Tianwen-1 Mars orbiter.

According to the CNSA [China National Space Administration], the orbiter will enter the remote-sensing orbit of Mars in early November to carry out global detection and obtain scientific data such as morphology and geological structure, surface material composition and soil type distribution, atmospheric ionosphere, and space environment of Mars.

The orbiter will also relay the communication between the rover and Earth for the rover’s extended mission, the CNSA added.

Based on this information, full communications with the rover Zhurong will not resume until November because the orbiter needs to re-adjust its orbit.

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Curiosity’s new mountain views

1:14 pm

Curiosity's future route
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With the resumption of communications with Mars, following the two week hiatus because the Sun was in the way, Curiosity is about to begin its travels again. The view above, taken by the right navigation camera and reduced and annotated to post here, looks forward, with the red dotted line indicating the planned route.

The distinct white outcrop on the right top is the same spectacular outcrop I have highlighted previously.

At the moment however the rover is not going anywhere. Just before the hiatus the scientists had Curiosity move a short distance to crush some nearby nodules so that they could see their interior. At their update they post an image of one crushed nodule, and write the following:

[L]ook closely for very straight imprinted lines in the middle of flattened areas that appear slightly more grey. You can also see cracks, especially clearly on the right of the nodule in the image, but if you look around, you’ll find there are more of them. Some of the scratched areas are looking white, too. All those features will allow us an insight into the nodules and an interpretation beyond what we can otherwise see on the surface.

The image below, also taken by the right navigation camera and reduced to post here, looks back at Curiosity’s earlier travels, across the floor of Gale Crater about 1,500 feet below. The rim, about 25 miles away, can be seen through the atmospheric haze as the distant mountain chain.

See the orbital map at this post in September to get the context of what the two images are viewing. The top image looks south along the cliff line, the bottom looks almost due north.
Looking across Gale Crater
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A collapsing north wall in Valles Marineris

2:05 pm

Mass wasting in Valles Marineris
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on July 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label as an alluvial fan.

I have also seen them label this kind of avalanche as mass wasting, where the material moves down slope suddenly in a single mass.

The image shows the aftermath of such an event, after a large blob of material broke free from the mountainside and slid almost as a unit downhill to settle more than two miles away on the floor of the canyon. The distance traveled and the blobby nature of the flow both reveal how the lower Martian gravity changes the nature of such events, compared to what you might see on Earth. The flows can travel farther, and can hold together as a unit easier.

The overview map below not only provides the context, but it tells us that such events are remarkably common in this place.
» Read more

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Scientists resume communications with U.S. Martian rovers

9:11 am

Example of first rover images downloaded following communications break
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Both U.S. Mars rovers Curiosity and Perseverance have resumed communications with Earth, each downloading a bunch of images that they had been programmed to take during the two week communications hiatus from October 3 to October 17, caused by the Sun being between the Earth and Mars.

Most of the images are a variation of the one to the right, reduced to post here, taken by Curiosity’s left hazard avoidance camera. As neither rover moved during the communications break, the scientists limited most photography to only a handful of cameras, with the photographs mostly confirming day to day that the rover and its instruments were functioning.

You can see all of Curiosity’s new images here. Perseverance’s new images can be viewed here. (To see the new Perseverance images click on “latest images.”)

A Curiosity team update today notes the work they plan to do in the coming days as they gear up for future travels. The Perseverance update today focused more on the paper published during the break that confirmed, using data from the rover, that Jezero Crater once contained a lake.

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The icy Phlegra Mountains on Mars

1:37 pm

Overview map

Cool image time! The Phlegra Mountains on Mars are probably the iciest mountains on the red planet, something I noted previously in an April 2020 essay, highlighting a half dozen images from the high resolution camera on Mars Reconnaissance Orbiter (MRO) that showed that iciness. As I stated:

Here practically every photograph taken by any orbiter appears to show immense glacial flows of some kind, with some glaciers coming down canyons and hollows [#1], some filling craters [#2], some forming wide aprons [#3] at the base of mountains and even at the mountains’ highest peaks [#4], and some filling the flats [#5] beyond the mountain foothills.

And then there are the images that show almost all these types of glaciers, plus others [#6].

The overview map above not only shows the locations of these six images in black, it also shows in red two of SpaceX’s four prime candidate landing sites for its Starship spacecraft. Note that #3 above is one of those sites.

The white rectangle in the Phlegra Mountains marks the location of today’s cool image below, taken on June 11, 2021 by MRO’S high resolution camera.
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Dry Martian chaos

1:52 pm

Dry chaos on Mars
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On Mars, one of the most common kinds of landscape is called chaos terrain. Made up of mesas, buttes, and cross-cutting random canyons, this geology is not seen on Earth, and when first identified by scientists in early orbital pictures in the 1970s, it baffled them. While it is clear that some form of erosion process caused it, the scientists did not have enough data then to figure out what that process was.

Today scientists have a rough theory, based on what they now know about Mars’ overall geology and its climate and orbital history. The canyons of chaos terrain were originally fault lines where either water or ice could seep through and widen. See this January 2020 post for a more detailed explanation.

Most of the cool images I have posted of chaos terrain have been in places in the mid-latitudes that are covered with glaciers. See for example this December 2019 post of one particular mesa in glacier country, with numerous glaciers flowing down its slopes on all sides. That mesa is quite typical of all such mesas in the mid-latitudes.

Today’s cool image above, cropped to post here, takes us instead to the Martian very dry equatorial regions. The photo was taken on May 17, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO), and like mid-latitude chaos, it shows a collection of random mesas with canyons cut almost randomly between.

Unlike the mid-latitudes, however, there is no evidence of glaciers here. Instead, the canyons and mesa slopes are covered with dust, shaped into wind-blown dunes.

As always, the overview map below gives us some context.
» Read more

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A gecko on Mars

12:24 pm

Gecko on Mars
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Today’s cool image is also today’s picture of the day from the science team of the high resolution camera on Mars Reconnaissance Orbiter (MRO. That picture, rotated, cropped, and reduced to post here, can be seen to the right. As the caption authors Sharon Wilson and Sarah Sutton write:

The smooth volcanic surfaces in the Gordii Fossae region are sometimes interrupted by long, narrow troughs, or fissures. These fissures form when underground faults, possibly involving magma movement, reach the near-surface, allowing material to collapse into pits or an elongated trough. This fissure appears to have erupted material that flowed onto the surface.

If you use your imagination, this trough resembles a gecko with its long tail and web-shaped feet!

This impression is even more evident in the wider image taken by MRO’s context camera below.
» Read more

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Dusty chaos in Martian canyons

1:37 pm

Outcrops in dusty chaos on Mars
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 30, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the dusty dry floor of the chaos region of rough terrain in a side canyon of Valles Marineris, near its outlet. The color strip and the bright outcrops suggest that this terrain contains interesting minerals and resources. To determine exactly what those materials are however requires more information not available in this photo.

This ancient chaos terrain is the leftover eroded sea floor of a intermittent inland sea, leftover water from the catastrophic floods that are theorized to have flowed out of Valles Marineris and carved its gigantic canyons.

The overview map below shows this hypothesized sea.
» Read more

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Ancient fossil river in the very dry equatorial regions of Mars

1:27 pm

Inverted Channel on Mars
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Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on August 29, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows what the scientists label an “inverted channel in Arabia Terra,” a small example of the more than 10,000 miles of fossilized rivers in this region on Mars that scientists have identified using MRO.

They are made of sand and gravel deposited by a river and when the river becomes dry, the channels are left upstanding as the surrounding material erodes. On Earth, inverted channels often occur in dry, desert environments like Oman, Egypt, or Utah, where erosion rates are low – in most other environments, the channels are worn away before they can become inverted. “The networks of inverted channels in Arabia Terra are about 30m high and up to 1–2km wide, so we think they are probably the remains of giant rivers that flowed billions of years ago. [emphasis mine]

Since this fossilized river is located at 11 degrees north latitude, smack in the middle of the dry equatorial regions of Mars, it has certainly been a dry desert for a very long time. You can see how barren the terrain appears by looking at the wider view afforded by MRO’s context camera below.
» Read more

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Data from Perseverance confirms Jezero Crater once held a lake

6:52 am

figure 5 from paper showing ancient lake in Jezero Crater

According to a newly published paper, the data obtained by the rover Perseverance has confirmed and refined what orbital data has suggested, that Jezero Crater once held a lake. From the abstract:

We analyze images taken by the rover in the three months after landing. The fan has outcrop faces that were invisible from orbit, which record the hydrological evolution of Jezero crater. We interpret the presence of inclined strata in these outcrops as evidence of deltas that advanced into a lake. In contrast, the uppermost fan strata are composed of boulder conglomerates, which imply deposition by episodic high-energy floods. This sedimentary succession indicates a transition, from a sustained hydrologic activity in a persistent lake environment, to highly energetic short-duration fluvial flows.

In other words, the crater first held a lake, which as it slowly dried out was periodically renewed by flash floods. The distinct delta of material that made Jezero Crater the prime landing site was apparently formed during the period when the lake existed. The conditions that caused the subsequent flash floods is as yet not been determined, though it likely is related to the red planet’s long term evolution.

The image above, figure 5 from the paper, shows the inferred lake in that early history. The red cross marks Perseverance’s landing site.

This data reinforces the fundamental scientific mystery of Mars. It shows evidence that liquid water once flowed on the surface of Mars, even though other long term data of the planet’s history says the Martian atmosphere has been too thin and too cold to allow that to happen. There is evidence that the atmosphere might have once been thicker, but no computer model or theory has been able to produce a time when it was warm enough.

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Report: Reduce contamination restrictions for some future Mars missions

10:35 am

A new policy paper from the National Academies has proposed reducing the planetary protection rules for some future Mars missions, concluding that Earth life cannot survive on Mars for long, and as long as a lander or rover does not land close to cave entrances or on extensive ice, the need to decontaminate is significantly reduced. From the press release:

In this report, the Committee focused on regions on Mars that might not be negatively impacted if visited by spacecraft that are not stringently sterilized. For missions that do not access the subsurface, such regions could include a significant portion of the surface of Mars, because the UV environment is so biocidal that terrestrial organisms are, in most cases, not likely to survive more than one to two sols, or Martian days. For missions that access the subsurface (down to 1 meter), regions on Mars expected to have patchy or no water ice below the surface might also be visited by spacecraft more relaxed bioburden requirements, because such patchy ice is likely not conducive to the proliferation of terrestrial microorganisms.

The report finds that it is imperative that any mission sent to Mars with reduced bioburden requirements remain some conservative distance from any subsurface access points, such as cave openings. Furthermore, though less stringent than current requirements, these missions with relaxed bioburden requirements would still need some level of cleanliness, which could be achieved for instance using standard aerospace cleanliness practices.

The report essentially concluded that missions to Mars’ dry equatorial regions as well as its glacial mid-latitudes pose no risk to contaminating the red planet with Earth life.

While the press release pushes the idea that this is a reduction in the planetary protection rules, it could be seen in a much worse light. Based on the proposed rules, missions to the Martian poles or higher latitudes, where ice is extensive and not “patchy,” might be entirely forbidden. This will significantly limit Martian exploration by the United States. Meanwhile, China and Russia and others will be faced with no such restrictions.

Note too that this report likely forbids SpaceX from landing its Starship in the company’s candidate landing sites, all of which are in the northern lowland plains ranging from 35 to 40 degrees north latitude. This region is thought to have extensive ice sheets very close to the surface. To land there, the rules proposed will either require extremely strict and very costly decontamination procedures, many of which do not even exist as yet, or will forbid landing there at all.

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The wavy and beautiful edge of the northern ice cap of Mars

12:32 pm

The scarp of the north pole icecap on Mars
Click for full image.

Cool image time! The photo to the right, cropped and reduced to post here, was taken on August 7, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the many layered scarp that forms the edge of the northern polar ice cap on Mars, probably more than 2,000 feet high.

Those layers are significant, as they indicate the many climate cycles that scientists think Mars has undergone over the eons as the red planet’s rotational tilt, or obliquity, rocked back and forth from 11 degrees inclination to as much as 60 degrees. At the extremes, the ice cap was either growing or shrinking, while today (at 25 degrees inclination) it appears to be in a steady state.

Why the layers alternate light and dark is not known. The shift from lighter colors at the top half and the dark bottom half marks the separation between the top water ice cap and what scientists label the basal unit. It also marks some major change in Mars’ climate and geology that occurred about 4.5 million years ago.
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Land of Martian slope streaks

12:37 pm

Land of Martian slope streaks
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Cool image time! The photo to the right, cropped and reduced to post here, was taken on May 21, 2021 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows a typical example of the many slope streaks found in the rough and very broken region north of the Martian volcano Olympus Mons, the largest in the solar system.

See this May 2019 post for a detailed explanation of slope streaks. While they appear to be avalanches, they do not change the topography of the ground, sometimes flow over rises, and appear to be a phenomenon entirely unique to Mars. While no theory as yet explains them fully, the two most favored postulate that they are either dust avalanches or the percolation of a brine of chloride and/or perchlorate in a thin layer several inches thick close to the surface. In both cases the streak is mostly only a stain on the surface that fades with time.

The location of this cool image however tells us something more about them.
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