Tag: Mars

Europe’s Trace Gas Orbiter achieves operational orbit around Mars

8:33 am

After a year of aerobraking to lower its orbit, the European Space Agency’s Trace Gas Orbiter has reached its planned orbit around Mars, and is about to begin studying the red planet’s atmosphere.

The primary goal is to take a detailed inventory of trace gases – those that make up less than 1% of the total volume of the planet’s atmosphere. In particular, the orbiter will seek evidence of methane and other gases that could be signatures of active biological or geological activity.

On Earth, living organisms release much of the planet’s methane. It is also the main component of naturally occurring hydrocarbon gas reservoirs, and a contribution is also provided by volcanic and hydrothermal activity. Methane on Mars is expected to have a rather short lifetime – around 400 years – because it is broken down by ultraviolet light from the Sun. It also reacts with other species in the atmosphere, and is subject to mixing and dispersal by winds. That means, if it is detected today, it was likely created or released from an ancient reservoir relatively recently. Previous possible detections of methane by ESA’s Mars Express and more recently by NASA’s Curiosity rover have been hinted at, but are still the subject of much debate.

The Trace Gas Orbiter can detect and analyse methane and other trace gases even in extremely low concentrations, with an improved accuracy of three orders of magnitude over previous measurements. It will also be able to help distinguish between the different possible origins. [emphasis mine]

The highlighted sentence is important. Pinpointing a region where methane is concentrated will allow scientists to better understand where it is coming from, and what is causing its release. It could be microbiological life, but it also could be from active volcanic processes. Finding either or both would be significant, to put it mildly.

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A spray of volcanic ejecta on Mars?

10:38 am

pit features on floor of crater

Time for some more weird Mars geology! Today the science team for the high resolution camera on Mars Reconnaissance Orbiter released its monthly batch of new images. There is a lot of interesting stuff buried therein, some of which I will feature periodically in the next month.

The image on the right, reduced in resolution to post here, is a good example. (If you click on the image you can see the full resolution version.) It shows a scattering of pits in three specific areas on the crater floor, all in a line going from the northeast to the southwest. Yet, the rest of the crater floor lacks similar pits, and is either very smooth or has a mottled appearance. Both the smooth and the mottled areas appear to have a very faint trend going from the northwest to the southeast, which to my eye appears caused by the general wind direction that flows across the crater floor.

Even more intriguing, the pits in these three areas appear to be mostly oblong and also trend from the northeast to the southwest, cutting across the general trend of the rest of the crater floor. You can see this in the cropped closeups from the full resolution image below, showing the two boxed areas indicated on the image on the right.
» Read more

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Near the Martian shoreline

1:20 pm

One of the prime areas of research for Mars planetary geologists is the region on Mars where the geography appears to transition from the southern cratered, rough terrain to the northern low, generally smooth, and flat plains. It is theorized by some scientists that the northern plains were once an ocean, probably shallow and probably intermittent, but wet nonetheless for considerable periods. The global map of Mars below, created by the laser altimeter on Mars Global Surveyor, clearly shows the obvious elevation differences between the low northern plans (blue) and the high, more cratered southern regions (changing from yellow to orange as you move higher).

Labeled global Map of Mars

Scientists have spent a considerable effort studying this transition zone (green on the map), illustrated by just one example I recently highlighted, showing that, though there does not appear to be a clear shoreline in many places, there is strong evidence that a shallow ocean repeatedly rose and fell in this transition zone, leaving behind geological ripple marks vaguely reminiscent of those seen on a beach caused by the rise and fall of the tides.

Today we highlight another example, taken in January 2018 at the location indicated by the cross on the above map.
» Read more

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ESA successfully completes first parachute test for 2020 ExoMars mission

9:33 am

Early in March the European Space Agency successfully completed the first of a series of parachute tests for its 2020 ExoMars rover mission.

The focus of the latest test, conducted in sub-zero conditions in Kiruna, Sweden earlier this month, was the 35 m-diameter second main parachute. The test demonstrated the deployment and inflation of the parachute with its 112 lines connected to a drop test vehicle, via the deployment of a smaller 4.8 m-wide pilot chute.

This test only tested the parachutes deployment system. They still need to do this test at high altitudes to duplicate Mars’ conditions using high-altitude balloons.

When ExoMars reaches Mars, the parachute will act to slow the spacecraft down during descent. For the actual landing, they will be using systems designed and built by the Russians.

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Mars rover update: March 21, 2018

2:10 pm

Summary: Curiosity continues its exploration of Vera Rubin Ridge, including several drilling attempts. Opportunity is halfway down Perseverance Valley.

For a complete list of all past updates going back to July 2016, see my February 8, 2018 update.

Curiosity

Curiosity's traverse map, Sol 1993

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

Since my February 8, 2018 update, the Curiosity science team has apparently been loath to leave Vera Rubin Ridge. They had begun the trek to the northeast that would take them towards the exit ridge heading to the southeast, as indicated by the dotted red line on the traverse map above, but then continued past that planned route to continue to the northeast. Along the way they attempted to drill twice using an improvised approach that they hoped would bypass the drill’s stuck feed mechanism, without apparent success.

The panorama below is looking to the west and south, as indicated by the yellow lines in the image above.
» Read more

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New theory suggests Mars’ oceans formed earlier and intermittently

11:19 am

Scientists have proposed a new model for the existence of oceans on Mars’ northern plains that proposes they formed earlier, were shallower, were variable in size, and formed in conjunction with the eruptions that formed the planet’s giant volcanoes.

The proposal by UC Berkeley geophysicists links the existence of oceans early in Mars history to the rise of the solar system’s largest volcanic system, Tharsis, and highlights the key role played by global warming in allowing liquid water to exist on Mars. “Volcanoes may be important in creating the conditions for Mars to be wet,” said Michael Manga, a UC Berkeley professor of earth and planetary science and senior author of a paper appearing in Nature this week and posted online March 19.

…The new model proposes that the oceans formed before or at the same time as Mars’ largest volcanic feature, Tharsis, instead of after Tharsis formed 3.7 billion years ago. Because Tharsis was smaller at that time, it did not distort the planet as much as it did later, in particular the plains that cover most of the northern hemisphere and are the presumed ancient seabed. The absence of crustal deformation from Tharsis means the seas would have been shallower, holding about half the water of earlier estimates. “The assumption was that Tharsis formed quickly and early, rather than gradually, and that the oceans came later,” Manga said. “We’re saying that the oceans predate and accompany the lava outpourings that made Tharsis.”

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Putin promises a Russian Mars mission in 2019

8:50 am

The new colonial movement: In a documentary released this week Russian President Vladimir Putin pledged that his country will send an unmanned mission to Mars in 2019, and that it will be aimed at studying water at the red planet’s poles.

This is funny. Putin is likely referring to ExoMars 2020, which Russia is partnering with the European Space Agency (ESA). In that mission, Russia is providing the rocket and the descent and landing technology for ESA’s rover. To claim that this is a Russian mission is a bit of an over-statement, since the only Mars-related equipment Russia is building involves the landing, and the ESA is also participating in that work.

Nonetheless, Putin’s words here illustrate how the competition is heating up. Every nation wants its share of the exploration of the solar system, and they are beginning to ramp up their efforts to make that happen.

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Martian craters go splat!

2:17 pm

Overview of the volcanic Tharsis Bulge on Mars

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

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

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

My first reaction on seeing the image was, “Did this impact not go splat when it hit?”
» Read more

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Ground too hard for Curiosity’s drill

7:47 am

A second drill attempt by Curiosity, using an improvised drilling technique designed to bypass the failure of the drill’s feed mechanism, once again failed to drill deep enough to obtain a sample.

After two drilling attempts, Curiosity’s drill was not able to dig into the bedrock sufficiently to collect a sample of rock at this location. Curiosity’s engineers are continuing to refine the new drilling method. In the future, this might include adding percussion, which could enable drilling into harder rock.

Either the ground on Vera Rubin Ridge is too hard for Curiosity’s drill, or the new drilling technique does not allow the drill to push with the same force as previously. The update at the link implies the former, but I suspect the latter is a factor as well.

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More weird Mars geology

8:55 am

Low resolution of full image of crater

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

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

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

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

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

The map below the fold provides the location context for this crater, with the crater’s location indicated by the arrow.
» Read more

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Mars Reconnaissance Orbiter comes out of safe mode

7:28 am

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

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

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

Overall this sounds like very good news.

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Curiosity attempts to drill with improvised technique

7:06 am

The Curiosity engineering team has made the first attempt to drill in more than a year, using an improvised technique that has the rover arm push the bit into the ground rather than its presently non-function feed mechanism.

This early test produced a hole about a half-inch (1-centimeter) deep at a target called Lake Orcadie — not enough for a full scientific sample, but enough to validate that the new method works mechanically. This was just the first in what will be a series of tests to determine how well the new drill method can collect samples. If this drill had achieved sufficient depth to collect a sample, the team would have begun testing a new sample delivery process, ultimately delivering to instruments inside the rover.

According to the mission update page, for some reason the drill was unable to penetrate the ground very deeply.

They plan to do more tests, with the goal of eventually getting a hole deep enough to provide good samples.

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Microbes found that survive in the driest desert on Earth

6:18 am

Scientists have found that certain microbes can remain dormant for years in the Atacama Desert and then come to life during the rare times water is available.

The Atacama Desert stretches inland 1000 kilometers from the Pacific coast of Chile, and rainfall can be as low as 8 millimeters per year. There’s so little precipitation that there’s very little weathering, so over time the surface has built up a crusty layer of salts, further discouraging life there. “You can drive for 100 kilometers and not see anything like a blade of grass,” Neilson says. Although she and others have found some bacteria there, many biologists have argued that those microbes are not full-time residents, but were blown in, where they die a slow death.

But that didn’t deter Dirk Schulze-Makuch, an astrobiologist at the Technical University of Berlin. “I like to go to places where people say nothing is alive,” he says. “We decided to take a shotgun approach and throw all the new [analytical] approaches at everything—fungi, bacteria, viruses”—that might be there. He and his team collected samples from eight places in the Atacama—from the coast eastward to the driest places—over 3 years. They first gathered material a month after a record-setting rain in 2015, and then followed up with yearly collections in some of the same places in 2016 and 2017. They sequenced all the copies of a gene known to distinguish microbial species to determine what was in those samples and even recovered some full genomes. The researchers also did a test to determine the proportion of DNA that came from intact, living cells. Finally, they assessed the amount of cellular activity; of adenosine triphosphate (ATP), a molecule the fuels this activity; and of byproducts—including fatty acids and protein building blocks—that resulted from that activity to look for additional evidence of life.

The coastal samples contained the most number and diversity of microbes, but in 2015, there were signs of life even in the driest spots, Schulze-Makuch and his colleagues report today in the Proceedings of the National Academy of Sciences. “Following a rainfall event, there is a flush of activity and [cells] are replicating,” Neilson says.

The researchers, as well as the article, push the idea that this result makes life on Mars more possible, but I think that is pushing things quite a bit. The Earth is so filled with life that to find a spot that doesn’t have life on it is almost impossible. The odds work in the favor of hardy life in difficult places. Mars however appears generally lifeless, which makes the odds of there being life more unlikely. Moreover, while the Atacama has many similarities to Mars, the differences are quite profound. To extrapolate any possibilities to Mars from this research is a big overstatement.

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Curiosity science team to attempt first drilling in a year

10:54 am

After a year of tests and engineering rethinking, the Curiosity science team has decided to attempt drilling its first hole in more than a year.

From yesterday’s Curiosity mission update:

Because there is only so much data volume and rover power to go around, performing drill activities must temporarily come at the expense of scientific investigations (although you’d be pressed to find a disappointed science team member this week, as the drilling campaign will bring loads of new scientific data!). As a result, with the exception of some environmental observations by the Rover Environmental Monitoring Station (REMS) instrument, today’s plan does not have any targeted scientific observations within it. Today will instead be dedicated to drill preload activities and imaging for engineering and rover planning purposes in preparation for a full test of the revised drilling operations.

The problem with the drill has been its feed mechanism, the equipment that moves the drill downward into the hole. As designed the robot arm would get planted on the surface to provide stability for the drill, which as it drilled would be pushed downward that that feed mechanism. Last year they found something had clogged that mechanism so that it would not retract properly.

From what I understand, what they have tested and have decided to try instead is to place the drill against the surface in an extended position, and use the arm itself to push the bit downward. The concern is whether the arm can hold the drill steady. They have done some tests and think it can. We shall soon find out.

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Mars Reconnaissance Orbiter in safe mode

8:26 am

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

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

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

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

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Aligned erosion lines of Perseverance Valley

4:52 am

The uncertainty of science: Last week, while I was flying to Israel, the Opportunity science team announced the discovery of strange aligned erosion lines, what they are calling stone stripes, in Perseverance Valley.

The ground texture seen in recent images from the rover resembles a smudged version of very distinctive stone stripes on some mountain slopes on Earth that result from repeated cycles of freezing and thawing of wet soil. But it might also be due to wind, downhill transport, other processes or a combination.

…On some slopes within the valley, the soil and gravel particles appear to have become organized into narrow rows or corrugations, parallel to the slope, alternating between rows with more gravel and rows with less.

The origin of the whole valley is uncertain. Rover-team scientists are analyzing various clues that suggest actions of water, wind or ice. They are also considering a range of possible explanations for the stripes, and remain uncertain about whether this texture results from processes of relatively modern Mars or a much older Mars.

For those who are regular readers of Behind the Black, you already knew about a variation of this discovery back in November 2017, from my regular rover updates. Then, they discovered aligned groves in the gravel that looked to me like slickensides, erosion patterns produced by glacial activity. The science team told me, however, that they were favoring wind, not ice, as a primary cause, though that conclusion was far from certain.

In the press release last week, they focused more on the aligned erosion patterns in the fine gravel that appear to align perpendicular to the slope. Though they think they have found a comparable Earth-based phenomenon that might explain these patterns, it appears that the science team remains just as unsure of their cause as they are for the rocks.

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Massive flow on Mars

9:59 am

Massive flow on Mars

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

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

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

Point of origin for flow

Location of flow, west of Olympus Mons

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

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

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

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A good health check for Mars Reconnaissance Orbiter

10:32 am

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

This item is probably the biggest cause for concern:

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

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

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Mars rover update: February 8, 2018

2:01 pm

Summary: Curiosity remains on Vera Rubin Ridge, though it has begun moving toward the point where it will move down off the ridge. Opportunity remains in Perseverance Valley, though it has finally taken the north fork down.

Before providing today’s update, I have decided it is time to provide links to all previous updates, in chronological order. This will allow my new readers to catch up and have a better understanding of where each rover is, where each is heading, and what fascinating things they have seen in the past year and a half.

These updates began when I decided to figure out the overall context of Curiosity’s travels, which resulted in my March 2016 post, Pinpointing Curiosity’s location in Gale Crater. Then, when Curiosity started to travel through the fascinating and rough Murray Buttes terrain in the summer of 2016, I stated to post regular updates. To understand the press releases from NASA on the rover’s discoveries it is really necessary to understand the larger picture, which is what these updates provide. Soon, I added Opportunity to the updates, with the larger context of its recent travels along the rim of Endeavour Crater explained in my May 15, 2017 rover update.

Now to talk about the most recent news from both rovers!
» Read more

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Curiosity takes a panorama that shows its entire journey so far

5:24 pm

Cool image time! The Curiosity science team has released a panorama taken in October 2017 that looks north across the floor of Gale Crater and shows the rover’s entire journey since it landed in 2012.

Rather than post the image here, I have posted below the fold a video produced by the science team that pans across the entire panorama, and then shows where Curiosity has traveled in that panorama. Look close, and you will realize how truly little of Mars we have so far explored.
» Read more

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The landing site of NASA’s next Mars lander

6:55 pm

InSight's landing site on Mars

InSight, NASA’s next Mars lander scheduled to launch later this year (two years late), is aiming for a landing site in a region called Elysium Planitia, a flat plain north of the equator.

InSight’s scientific success and safe landing depends on landing in a relatively flat area, with an elevation low enough to have sufficient atmosphere above the site for a safe landing. It also depends on landing in an area where rocks are few in number. Elysium Planitia has just the right surface for the instruments to be able to probe the deep interior, and its proximity to the equator ensures that the solar-powered lander is exposed to plenty of sunlight.

The target area is centered at 4.5 N latitude and 135.9 East longitude. If you zoom in on that latitude and longitude at the archive of Mars Reconnaissance Orbiter (MRO) high resolution images, you get the red blob on the right, which shows how many images they have taken of this area in preparation for InSight’s mission. The X indicates the location of lat/long above.

Below the fold is a reduced version of the MRO image for the center of this target area. The black spots near the center are thought to be a recent crater impact site. In general, this image shows an area with more features than the region around it. Most of the landing area of Elysium Planitia is a featureless flat plain with scattered small craters. Since InSight is not a rover, where it lands will be where it does its research, so there was no reason to pick a site with lots of interesting surface features. Moreover, since InSight is focused not on studying the surface but the interior geology of Mars, it matters little what the surface looks like anyway. One instrument will be a seismograph, while another will insert a thermometer about sixteen feet into the ground to measure the interior temperature.
» Read more

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Weird Martian geology: Kaiser Crater

9:58 am

Kaiser Crater bedrock

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

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

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

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Mars rover update: January 16, 2018

2:09 pm

Summary: Both rovers have moved little in the past month, Opportunity because it is in a good science location and because it must save energy during the winter and Curiosity because it is in a geological location so good the scientists appear to almost be going ga-ga over it.

Curiosity

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

In the month since my December 18 update, Curiosity has continued to head south rather than east as originally planned (as indicated by the dotted yellow line in the traverse map to the right). Moreover, the rover has not moved very much, because the science team has decided that there is just too much significant geology in this area on Vera Rubin Ridge, also part of a geological unit they have dubbed the Hematite Unit.

Right now the rover is located at an area they call “Region e,” one of the three patches I have also indicated on the image to the right. From the second update below:

This location is a slight depression with exposed fractured bedrock that appears more “blue” from orbit than the surrounding region. In addition, the orbital evidence and observations from the ground suggest that this location is similar to “Region 10” that we visited just last week, which was shown to have some pretty spectacular small-scale features that were of particular interest to many on the science team. As a result, the team was very excited to reach “Region e” and begin our scientific investigation!

The last few updates on the Curiosity mission update page indicate the excitement the geologists have for this site:
» Read more

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The known ice cliffs on Mars

12:20 pm

Last week there was a big NASA story about the discovery of eight locations on Mars where the evidence strongly suggests that these spots have cliff faces with exposed layers of water ice.

The press release however did not provide an overview about where those eight locations were. Only two locations were given, one for a scarp in Milankovič Crater in the northern hemisphere, and one in an area called Promethei Terra, located in the remote cratered highlands in the southern high-mid-latitudes.

The location of known ice scarps on Mars

After much digging (and some assistance from John Batchelor) I was finally able to obtain the latitudes and longitudes of all 8 locations. All but the scarp in Milankovič Crater crater (shown by the white dot north of Olympus Mons) are located in the white rectangular box shown to the south and east of Hellas Basin, the area with Mars’ lowest elevation. This part of Mars is not well imaged with the high resolution camera on Mars Reconnaissance Orbiter (indicated by the fewer number of red squares in the image), mostly because it appears relatively boring from a distance. Nothing appears to be there for hundreds and hundreds of miles except craters, sand, and sand dunes..

The discovery of these scarps in this area however changes the picture. It suggests that cratered highlands that surround Hellas Basin, including those close to the planet’s equator, could contain similar buried layers of ice. More research is necessary to pin down more locations, especially those closer to the equator where conditions might be more hospitable for a colony.

Moreover, educated readers of Behind the Black have previously noted that because of Hellas Basin’s low elevation the air pressure there is thicker, and therefore the location has some advantages as a potential colony location. These ice scarps raise the value of Hellas Basin considerably, as they suggest that such layers could easily be exposed as you descend into Hellas Basin. If such layers are exposed on the northern flanks of the basin, they would be at latitudes of around 25 to 30 degrees south, a much more friendly latitude for settlement.

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Exposed mid-latitude ice deposits found on Mars

4:26 pm

Scientists have discovered eight locations on Mars where underground ice appears to be exposed on cliff faces

The scarps directly expose bright glimpses into vast underground ice previously detected with spectrometers on NASA’s Mars Odyssey orbiter, with ground-penetrating radar instruments on MRO and on the European Space Agency’s Mars Express orbiter, and with observations of fresh impact craters that uncover subsurface ice. NASA sent the Phoenix lander to Mars in response to the Odyssey findings; in 2008, the Phoenix mission confirmed and analyzed the buried water ice at 68 degrees north latitude, about one-third of the way to the pole from the northernmost of the eight scarp sites.

The important thing about this discovery is that, though we have known for several years that water ice exists underground in the Martian mid-latitudes, this is the first time we have identified specific places there it is exposed and accessible.

Unfortunately, the press release does not provide the specific eight locations, except for the one image, which is located in the southern hemisphere in a region called Promethei Terra, far from areas that have been studied much more extensively. I will do some digging to see if I can identify the other seven locations.

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A spectacular collapse feature at Arsia Mons

3:55 pm

Collapse at Arsia Mons

Cool image time! This post could be called an update to my January 8th post, Exploring Arsia Mons. In that post I had compiled together the ten images of Arsia Mons, the southernmost volcano in the line of three giant volcanoes on Mars, that JPL had highlighted over several weeks in early January.

Today, I decided to do some of my own exploration of some of the many images taken of Arsia Mons by all of the Martian orbiters. My goal had been to explore the volcano’s western slopes (an area that had not been featured in the JPL releases) because that is the area where research has found evidence of past glacial activity as well as seasonal water clouds. I haven’t finished that survey, but in the process I came across a spectacular image of a collapse that had been visible in image nine of the January 8th post, but did not stand out there because of the lighting. The image on the right is that better image, cropped to focus in on the collapse itself.

The material at the base of the wall resembles piled up mud, which suggests this collapse is a Martian version of a mud slide. If so, it also suggests the presence of liquid. At the same time, the muddy look might not be from liquid but because of the lighter Martian gravity causing avalanches to be appear different there. The light gravity means material is not as dense, so when it collapses it might break apart more easily into a sandy type flow.

I am only an amateur geologist, so my theories here should not be taken very seriously. Nonetheless, I am sure there are planetary geologists who have looked at this closely because of the information about Martian geology that they can glean from it. I’d be curious to hear their thoughts.

Meanwhile, my exploration of the western slopes of Arsia Mons will continue. In Pioneer the science fiction book I wrote in the early 1980s (now available), I placed my Martian colony in Mangala Valles, a meandering canyon to the west of Olympus Mons that feeds out from the higher southern regions into the lower northern flat plains where even then some scientists thought an ocean might have once existed. My thinking then was that this might be a good location to find underground water. It now appears, with our greater knowledge, that the slopes of the volcanoes themselves might be more promising, and I am curious to find the most likely places in this region where a future colony might end up.

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Exploring Arsia Mons

2:01 pm

Master index

In November over a period of two weeks the Mars Odyssey team posted ten images of Pavonis Mons, the smallest of the aligned three giant volcanoes just to the east of Olympus Mons, the largest known volcano in the solar system. I then made all of those images available in a single link, with some analysis.

They have now done the same thing for the southernmost (and possibly the most interesting) of those three aligned volcanoes, Arsia Mons. From the first image below:

Arsia Mons is the southernmost of the Tharsis volcanoes. It is 270 miles (450km) in diameter, almost 12 miles (20km) high, and the summit caldera is 72 miles (120km) wide. For comparison, the largest volcano on Earth is Mauna Loa. From its base on the sea floor, Mauna Loa measures only 6.3 miles high and 75 miles in diameter. A large volcanic crater known as a caldera is located at the summit of all of the Tharsis volcanoes. These calderas are produced by massive volcanic explosions and collapse. The Arsia Mons summit caldera is larger than many volcanoes on Earth.

In other words, you could fit almost all of Mauna Loa entirely within the caldera of Arsia Mons.

The image on the right above is the master index, annotated by me to show the area covered by each image. The images can accessed individually below.
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Curiosity images small tubelike rock features on Vera Rubin Ridge

12:24 pm

tubes on Mars

During Curiosity’s extended science observations in the past month on Vera Rubin Ridge the rover has found a number of rocks with strange tubelike features that remind some scientists of fossils. The image on the right, taken by the rover’s Mars Hand Lens Imager (MAHLI) and cropped and reduced to post here, shows some of these weird tubes.

The origin of these odd features — geological or biological processes — is in TBD limbo at the moment. Regarding trace fossils on Mars, “we don’t rule it out,” Vasavada said, “but we certainly won’t jump to that as our first interpretation.”

Close-up looks at these features show them to be angular in multiple dimensions. That could mean that they are related to crystals in the rock, perhaps “crystal molds” that are also found here on Earth, Vasavada added. Crystals in rock that are dissolved away leave crystal molds, he said.

Still, that’s just one of a few possibilities, Vasavada explained. “If we see more of them … then we begin to say that this is an important process that’s going on at Vera Rubin Ridge,” he said.

The article outlines a number of other possible explanations, including fossil remains. None are convincing at this time, based on the limited data. Nor does Curiosity have the equipment to clarify things much.

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A faint seasonal fluctuation of methane on Mars?

8:23 pm

The uncertainty of science: Data from Curiosity during its two Martian years on Mars have revealed a faint but distinct seasonal fluctuation in the amount of methane in the local atmosphere, a fluctuation that scientists do not have a good explanation for.

Since landing in 2012, Curiosity has on 30 occasions opened a few valves to the martian night and taken a sniff of the thin, frigid air. In a small, mirrored chamber, it shines a laser through the air sample and measures the absorption at specific wavelengths that indicate methane. At the meeting, Webster reported vanishingly small background levels of the gas: 0.4 parts per billion (ppb), compared with Earth’s 1800 ppb.

Where that whiff comes from is the heart of the mystery. Microbes (including those that live in the guts of cows and sheep) are responsible for most of Earth’s methane, and Mars’s could conceivably come from microbes as well—either contemporary microbes or ancient ones, if the methane they produced was trapped underground. But methane can also be made in ways that have nothing to do with biology. Hydrothermal reactions with olivine-rich rocks underground can generate it, as can reactions driven by ultraviolet (UV) light striking the carbon-containing meteoroids and dust that constantly rain down on the planet from space.

Now, add to the methane puzzle the seasonal variation Curiosity has detected, with levels cycling between about 0.3 ppb and 0.7 ppb over more than two martian years. Some seasonality is expected in an atmosphere that is mostly carbon dioxide (CO2), says François Forget, who models the climate of Mars at the Laboratory of Dynamical Meteorology in Paris. In the southern winter, some of that CO2 freezes out onto the large southern polar cap, making the overall atmosphere thinner. That boosts the concentration of any residual methane, which doesn’t freeze, and by the end of northern summer this methane-enriched air makes its way north to Curiosity’s location, Forget says. Seasonal variations in dust storms and levels of UV light could also affect the abundance of methane, if interplanetary dust is its primary source.

But, Webster said at the meeting, the seasonal signal is some three times larger than those mechanisms could explain. Maybe the methane—whatever its source—is absorbed and released from pores in surface rocks at rates that depend on temperature, he said. Another explanation, “one that no one talks about but is in the back of everyone’s mind,” is biological activity, says Mike Mumma, a planetary scientist at Goddard Space Flight Center in Greenbelt, Maryland. “You’d expect life to be seasonal.”

They have a lot of theories, from asteroids to alien life, but none really explains this adequately.

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