InSight’s power level holding steady

InSight's on-going power levels

The Energizer bunny of Mars, the InSight lander, continues to hold on. The engineering team tonight issued another status report, as shown in the graph to the right. For the past week the lander continued to produce 420 watt-hours per day, even though the tau level of dust in the atmosphere increased from 0.8 to 0.85.

The tau level of dust outside of the winter dust season is normally between 0.6 and 0.7. Even though Mars is moving out of winter, that level has increased slightly above InSight. And yet, even with a higher dust content and thus less sunlight, the lander’s dust-covered solar panels are generating power, at a very slightly higher level.

The InSight team had expected the lander to die in early September, at the latest. Instead, it keeps running, thus allowing it to detect on September 5th an impact created by a cluster of three asteroids, the first time scientists have ever pinpointed exactly when such a new impact occurred on Mars.

For the lander to survive for even longer, all it needs is one gust of wind across the solar panels to clean them off. The science team had expected this to happen periodically, based on past experience with the Spirit and Opportunity rovers. Unfortunately for InSight, it has not yet happened even once since it arrived on Mars in 2018. Nonetheless, it only has to happen once to save the lander.

Stay tuned. All is not yet lost.

InSight’s seismometer detects its first new impact on Mars

Martian impact discovered by InSight
Click for full image.

Using data from InSight’s seismometer that suggested a new impact had occurred at a specific location on September 5, 2022 on Mars, scientists used the high resolution camera on Mars Reconnaissance Orbiter (MRO) to search and find that impact.

The photo to the right, reduced to post here, is that MRO photo.

The initial impact itself created a small marsquake that was detected by InSight’s seismometer. The instrument recorded seismological data that showed the moment the meteoroid entered Mars’ atmosphere, its explosion into pieces in the atmosphere, and finally, the impact that created a series of at least three craters in the surface.

MRO then flew over the approximate site where the impact was “felt” to look for darkened patches of ground using its Context Camera. After finding this location, HiRISE captured the scene in color. The ground is not actually blue; this enhanced-color image highlights certain hues in the scene to make details more visible to the human eye – in this case, dust and soil disturbed by the impact.

This was thus the first new Martian impact detected based on its actual occurrence, rather than simply finding a change between two photos taken at different times. The latter only tells you a time period when the impact occurred. InSight’s detection here marks the impact’s exact moment.

Nor is this the only such discovery. It appears that InSight detected at least two other impacts (here and here), that only subsequently were linked to MRO impacts. In those cases, the new impact had already been found by MRO, and only afterward were scientists able to identify its seismic vibration in InSight data, thus pinpointing the exact date it took place.

InSight’s power levels rise again

InSight's power levels through September 10th

Based on another status update issued today by the InSight science team, the electricity generated by the Mars lander’s dust-covered solar panels increased again slightly in the past week, going from 410 watt-hours per day to 420 watt-hours per day.

The graph to the right shows the trends since May. The science team had expected the power levels to steadily drop throughout the summer so that by early September the lander would die.

Instead, the power levels remained steady throughout the summer, and have in the past two weeks actually risen slightly, thus extending InSight’s life.

If at any moment a strong gust of wind or dust devil sweeps over InSight, the panels could be blown clear and it would gain a rebirth. The longer it manages to survive, the greater the chance that this might happen.

InSight’s power level goes up!

InSight's power levels as of September 5, 2022

The most recent status update on the Mars lander InSight, released today, shows a slight rise in the amount of power generated by its dust-covered solar panels.

As shown on the graph to the right, on August 27, 2022 the power level was 400 watt-hours generated per Martian day. On September, 5, 2022, the power level was 410 watt-hours per Martian day, the first power increase since late July. At the same time, the dust in the atmosphere continued to clear, going from a tau level of .88 to 0.8. Outside of the winter dust season tau is usually between 0.6 and 0.7.

The slight power increase continues to suggest that the lander’s death might be delayed. At 400 watt-hours per day, it has been able to run its seismometer since the beginning of July. With this slight increase, the chance increases that InSight will finally get that one gust of wind or dust devil that will blow the dust off its solar panels and allow it to recover some power and operate for longer.

InSight power levels continue to hold steady

InSight power levels through August 27, 2022

According to a new update posted today by the InSight science team, the power being generated by the lander’s dust-covered solar panels once again did not decline last week, holding at 400 watt-hours generated per day for the fifth week in a row.

The graph to the right shows the trends since May. The dust in the atmosphere is indicated by the red line, marking what scientists call the tau level. A normal level outside of the winter dust season should be between 0.6 and 0.7 tau. Even though that dust season has been ending, that level has remained high, thus cutting off more of the sunlight that the Mars lander could use to generate the electricity needed by its seismometer.

That the power generated continues to hold steady however suggests that InSight’s seismometer might be able to continue working into September, detecting Martian earthquakes. The scientists had predicted the spacecraft would die sometime around now. Without doubt they are thrilled their prediction appears wrong.

That the lander might last longer also increases the chance that it might experience a wind event, such as a dust devil, that could blow the solar panels clear of dust and save the lander entirely. All it needs is one such event, which sadly has not occurred since InSight landed on Mars in 2018.

InSight power levels remain steady on Mars

InSight's status through August 21, 2022

The InSight science team today released its weekly update on the lander’s ability to generate power from its dust-covered solar panels, I have charted the new numbers, through August 21, 2022, on the graph to the right. From the update:

InSight was generating an average of 400 watt-hours of energy per Martian day, or sol. The tau, or level of dust cover in the atmosphere, was estimated at .88 (typical tau levels outside of dust season range from 0.6-0.7).

For the fourth straight week the daily power level remained steady, not dropping as predicted by engineers to a point in August that the mission would end. As it appears the seismometer can function when the panels produce 400 watt-hours per day, the lander is thus holding its own instead of shutting down.

That the amount of dust in the atmosphere increased slightly is both good and bad news. The good news: Even with slightly more dust, InSight’s power levels did not drop. The bad news: There is still plenty of dust in the air that can settle on the solar panels and further degrade their ability to generate electricity.

InSight’s future is thus a day-to-day thing, though it appears at this moment that it can likely continue to gather earthquake data for another week.

InSight’s power status continues to hold steady on Mars

InSight power status through August 14, 2022

According to a new status update posted today by the science team, the power status for the Mars InSight lander continues to hold steady.

The graph to the right adds the new data, showing that the daily watt hours of power produced each day continues to hold at 400, while the dust in the atmosphere continues to drop towards its normal level of between 0.6 and 0.7 tau during the non-dust seasons.

These new numbers appear to be generally good news. Even though the dust continues to settle out of the atmosphere, it does not appear to be adding dust on the solar panels that would reduce their capability to generate power. Though the science team had predicted that the power levels would cause the mission to end sometime in August, at 400 watts per hour InSight has apparently continued to generate enough electricity to keep its seismometer running for at least another week.

InSight seismometer data suggests no underground ice at landing site

Using a computer model combined with seismometer data gathered by the Mars lander InSight, scientists have concluded that there is little or no underground ice in the equatorial region where InSight sits.

From the paper’s abstract:

We use rock physics models to infer cement properties from seismic velocities. Model results confirm that the upper 300 m of Mars beneath InSight is most likely composed of sediments and fractured basalts. Grains within sediment layers are unlikely to be cemented by ice or other mineral cements. Hence, any existing cements are nodular or formed away from grain contacts. Fractures within the basalt layers could be filled with gas, 2% mineral cement and 98% gas, and no more than 20% ice. Thus, no ice- or liquid water-saturated layers likely exist within the upper 300 m beneath InSight. Any past cement at grain contacts has likely been broken by impacts or marsquakes.

As the lander sits just north of the equator in the red planet’s equatorial zone, which ample orbital data has suggested is a dry region (as shown in the global map below), this result is not a surprise. It does provide further confirmation however of this conclusion, that if there is any water on Mars within 30 degrees latitude of the equator, it will be deep underground, and likely only in certain regions.
» Read more

InSight’s power status holding steady on Mars

InSight's status as of August 9, 2022

Yesterday the InSight science team posted the lander’s ongoing power status, as it has been doing about every week since in June the team announced that they expected power to run out sometime in August, ending the mission.

I have created the graph to the right, showing the data from all those updates, to try to glean the overall trends. The red line indicates the tau level of dust in the atmosphere, essentially telling us how much that dust is blocking light from the Sun. Normally outside of dust season this number should range from 0.6 to 0.7. Since May 17 that dust level has been steadily declining, which thus increases the amount of sunlight reaching the panels.

The blue line marks the amount of power the lander’s panels have been able to produce. The lack of change in this line reveals both good and bad news. The good news is that the power level is holding steady, at a level that allows InSight’s one operating instrument, its seismometer, to continue to function. Should this power level continue to remain stable, that seismometer should be able to operate past August, thus extending the instrument’s life longer than expected.

The bad news is that the power levels are not going up as the dust level is dropping. This suggests that the dust layer on the panels that is preventing them from generating power is actually getting thicker. InSight has still not experienced any puff of Mars’ weak wind capable of blowing dust off those panels. Instead, as the dust settles out of the atmosphere with the end of dust season, some is settling on the panels themselves.

As new updates arrive I will update this graph. Stay tuned. InSight is not yet dead, though the vultures are unfortunately circling overhead.

InSight team decides to shorten lander’s life to operate seismometer longer

The InSight science team has decided to continue to operate the lander’s seismometer through August rather than turning it off at the end of June, even though that longer use will drain InSight’s batteries sooner and kill the lander shortly thereafter.

The previous plan would have allowed the lander to survive through the end of the year, but would have meant no earthquake data would have been gathered after June.

To enable the seismometer to continue to run for as long as possible, the mission team is turning off InSight’s fault protection system. While this will enable the instrument to operate longer, it leaves the lander unprotected from sudden, unexpected events that ground controllers wouldn’t have time to respond to.

“The goal is to get scientific data all the way to the point where InSight can’t operate at all, rather than conserve energy and operate the lander with no science benefit,” said Chuck Scott, InSight’s project manager at NASA’s Jet Propulsion Laboratory in Southern California.

Apparently they have realized that it is now very unlikely that a dust devil will come by and clear the dust from InSight’s solar panels, so keeping the spacecraft alive longer — but getting no data — does not make sense.

InSight likely to shut down by the end of summer

Martian quake map as seen by InSight
Martian quake map as seen by InSight, adapted from this 2021
presentation [pdf]

According to the InSight science team, the Mars lander and its seismometer will likely shut down operations by the end of the summer due to lack of power.

“Towards the end of summer of ’22, we anticipate our seismometer will be turned off, not because we want to turn it off but unfortunately, we don’t have the energy to run it,” Garcia said. She said the team will use it intermittently after that as long as power is available, but by the end of the year the spacecraft is expected to fall silent.

The intermittent readings of the seismometer will be of extremely limited use, as it will then be pure luck whether it detects a quake, and any detection will not provide the true rate of quakes on Mars.

The loss of power is due to dust on the solar panels. The team had hoped a dust devil would come by periodically to blow the panels clean, as happened routinely with the Spirit and Opportunity rovers, but InSight has not been so lucky.

It appears the safe mode that occurred shortly after InSight detected its largest Mars quake yet on May 10th was very temporary, though right now the seismometer is essentially the only instrument they have power to run.

Overall, this mission has a very spotty history. Its launch was delayed two years when the French attempt to build the seismometer failed. The delay cost NASA’s planetary program $150 million, at a minimum.

Then lander’s second of two main instruments, a German experiment to dig down 16 feet to insert a heat sensor into the ground, failed when its digging tool, dubbed the mole, was unable to penetrate the alien Martian soil.

Fortunately, InSight’s prime instrument, the seismometer (finally completed by JPL) worked, giving us a first look into the structure of Mars’ interior as well as where earthquakes are found on its surface.

InSight detects 5 magnitude Martian quake, the largest detected so far

The seismometer deployed by the Martian lander InSight has now detected its largest quake yet on Mars, with an estimated magnitude of 5.

NASA’s InSight Mars lander has detected the largest quake ever observed on another planet: an estimated magnitude 5 temblor that occurred on May 4, 2022, the 1,222nd Martian day, or sol, of the mission. This adds to the catalog of more than 1,313 quakes InSight has detected since landing on Mars in November 2018. The largest previously recorded quake was an estimated magnitude 4.2 detected Aug. 25, 2021.

The timing was very fortunate. Only three days later the power being generated by InSight’s dust-covered solar panels dropped too low, and the lander went into safe mode. Though its mission has been extended through the end of this year, the inability of the solar panels to produce energy because of dust has been predicted to shut down operations sooner. While it might be possible to restart science operations, this most recent safe mode situation could very well be that moment.

Meanwhile, scientists will analyze the data of this most recent large quake to attempt to pinpoint its location. They will also study it to gain a better understanding of the interior structure of Mars.

A quake south of Starship’s prime landing sites on Mars

The lowlands south of Starship's prime landing site
Click for full image.

Cool image time! The photo to the right, rotated, cropped, and reduced to post here, was taken on February 23, 2022 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). Though it shows the largely featureless northern lowland plains of Mars, it is particularly interesting for two reasons.

First, according to the photo’s label this scarp/ridge is apparently near a quake detected by the seismometer placed on Mars by the lander InSight, located about a thousand miles to the southwest. Though no information of the strength of this quake is available, it is likely to have been a small and weak one, interesting mostly because it indicates some small underground instability or a recent small impact on the surface. The image favors the former, as it shows no obvious recent features of change. What it does show is one very intriguing flow feature draping the scarp. As the location is at 34 north latitude in a region where scientists have found a lot of evidence of water ice very close to the surface, the flow could very well be glacial in nature, though dismissing a lava origin would be a mistake.

The second reason this location is of interest is what lies relatively nearby, as shown in the overview map below.
» Read more

InSight scientists publish paper describing last year’s big Martian quakes

Figure 5: global map of located Martian quakes

The InSight science team has now published a paper [pdf] describing in detail what they gleaned from the two large earthquakes the lander detected on Mars last year, measuring 4.1 and 4.2 magnitudes.

The map above, figure 5 of their paper, marks their best estimate of the quakes’ locations, dubbed S0976a and S1000a. From the caption:

Mars surface relief map showing InSight’s location (orange triangle), the location of other located mars-quakes (magenta dots) that cluster around 30° distance, close to Cerberus Fossae, and S0976a, located within Valles Marineris just north of Sollis Planum. Because no back azimuth can be determined for S1000a, its location is predicted to be somewhere within the shaded region between 107° and 147° from InSight. The event’s preferred distance (116°) is marked with the white dashed line. The black dotted lines mark radii around InSight up to 80°.

A review of Mars Reconnaissance Orbiter (MRO) high resolution images of that part of Valles Marineris where S096a occurred will likely uncover a whole bunch taken since last August, all attempting to detect any actual surface changes produced by quake. I think I’ll do that review, and see if I can spot something.

The paper also notes the uniqueness of S1000a, which lasted 94 minutes, the longest so far detected on Mars. The complexity of its signal also makes locating it difficult, though the most likely possible locations — indicated by the white dashed line in the map above — crosses through the Tharsis Bulge where Mars’ biggest volcanoes are found.

Sadly, InSight will likely shut down before the end of this year due to loss of power, so until another seismometer is sent there no further Martian quakes will be detected.

InSight resumes limited science operations

InSight on February 5th resumed science operations, reactivating its seismometer to record Martian quakes.

As I suspected in my previous InSight update, the lander’s life is still coming to an end.

The mission, though, has been grappling with a gradual decline in the spacecraft’s power because of dust accumulating on its solar arrays. Unlike the Spirit and Opportunity rovers, whose arrays were regularly cleaned by atmospheric activity, dust has continued to accumulate on InSight’s arrays. At a meeting of MEPAG in June 2021, Banerdt projected that power levels would drop below that needed to keep the spacecraft alive in the spring of 2022.

That date has been pushed out slightly, but he said the long-term outlook for the lander still does not look promising. “Our current projections indicate that the energy will drop below that required to operate the payload in the May/June time frame and probably below survivability some time near the end of the year,” he said.

They might still squeeze a month or two more from the lander, but unless they are very lucky and a dust devil blows across it, the end is coming.

Contact restored with InSight after dust storm

The InSight science team has regained communications with the lander on Mars following a dust storm that caused it to shut down all operations entirely.

Though the tweet from the science team says the space craft is out of safe mode, that really doesn’t appear to be the case. Safe mode is a condition where a robot ceases all science operations, hunkers down, and awaits further orders. All that has happened here is that the engineers have regained contact after communications were lost on January 7th. No science is being done.

The resumption of communications is excellent news, however. They must now access how much power the lander’s solar panels are generating to see if they can turn InSight’s main instrument, its seismometer, back on. Those panels might be badly covered with dust, preventing operations.

InSight recovering from safe mode caused by Martian dust storm

Engineers have been able to regain contact with the Mars lander InSight after a Martian dust storm that put it in safe mode and cut off all communications for three days.

The mission’s team reestablished contact with InSight Jan. 10, finding that its power was holding steady and, while low, was unlikely to be draining the lander’s batteries. Drained batteries are believed to have caused the end of NASA’s Opportunity rover during an epic series of dust storms that blanketed the Red Planet in 2018.

The lander remains however in safe mode. The engineers hope they can resume limited science operations in about a week. Even before this even the limitations on InSight’s power generation due to dust on its solar panels had forced the science team to only gather data from the seismometer, and even then had to suspend all data gathering periodically.

Though the lander has survived this dust storm, it is presently unclear how much dust remains on its panels and thus how much power it can generate. If it only can generate enough power to keep the lander from freezing, but not do any science, it might be time to shut it down entirely.

InSight detects the three more large quakes on Mars, the most powerful measured so far

In the past month InSight’s seismometer has detected the three most powerful earthquakes so far measured on Mars, with one located in a region where no quakes had as yet been seen.

InSight spotted 4.2- and 4.1-magnitude temblors on Aug. 25, then picked up another roughly 4.2-magnitude quake on Sept. 18 that lasted for nearly 90 minutes, NASA officials announced on Wednesday (Sept. 22).

The previous record holder, which InSight measured in 2019, clocked in at magnitude 3.7 — about five times less powerful than a 4.2-magnitude quake.

At this time scientists have only been able to roughly pinpoint the location of the two August quakes, with the 4.1 quake occurring about 575 miles away, putting it in the volcanic plains where InSight sits and closer than the location of most of the previous large quakes near the long surface fissures dubbed Cerberus Fossae 1,000 miles away.

The August 4.2 quake’s is even more interesting, as its location is the farthest away of any so far detected, at an estimated distance of 5,280 miles away. The scientists presently suspect but have not yet confirmed that it may be located in the western end of Valles Marineris, Mars’ largest canyon.

The lander itself continues to fight a loss of power due to the amount of dust on its solar panels, forcing the science team to shut down practically all its other instruments so that the seismometer could continue operating.

Scientists refine Martian interior based on quakes detected by InSight

Martian quake map as seen by InSight

Scientists today published three studies in the journal Science outlining their conclusions about the interior of Mars, based on the quakes that have been detected by InSight since it arrived on Mars in November 2018.

Reporting in a trio of studies published in the July 23rd Science, the Insight science team has now analyzed about 10 marsquakes to make the first direct observations of the structure within another rocky planet. The results — a surprisingly thin crust, an undifferentiated mantle, and a larger-than-expected core — will help determine how Mars formed and evolved.

There results are essentially what was described in April by the InSight science team at the annual 52nd Lunar and Planetary Science Conference (and reported here but no where else), though now more carefully and thoroughly described.

The discovery that the Martian crust is much thinner than expected, either 12 or 24 miles thick, with a core that is still liquid, has ramifications that might help explain both the planet’s formation and its volcanic history and giant volcanoes.

One piece of good engineering news in connection with the lander InSight:

Despite a dust-fueled energy crisis earlier this year, the solar-powered lander has since regained some power-generating capacity. “We are at least safe for this season’s winter and probably far into 2022,” Stähler says.

Dust covering solar panels threatens to end InSight mission

The InSight science team has revealed that the amount of dust that presently covers the solar panels on the Mars lander has now reduced their available power by about 80%, and if a dust devil doesn’t soon blow the dust off they will have to shut the spacecraft down sometime in the next ten months.

“The dust accumulation on the solar arrays has been considerable. We have about 80% obscuration of the arrays,” said Bruce Banerdt, principal investigator for the InSight mission at NASA’s Jet Propulsion Laboratory (JPL) in Southern California, according to SpaceNews.

Banerdt showed the impact of the declining power levels during a June 21 meeting of NASA’s Mars Exploration Program Analysis Group. When InSight landed near the Martian equator in November 2018, he said, the robot was generating roughly 5,000 watt-hours of power. Today that level is less than 700 watt-hours.

None of this is a surprise. Both the Opportunity and Spirit rovers faced the same problems. Both however were able to recover because periodically a dust devil would fly over the rover and clear the dust from the solar panels.

InSight however has not so far been lucky. While it has seen many nearby dust devils with its camera, none has come close enough to sweep the solar panels clean.

As the power has declined they have shut off various systems in order to keep the lander’s prime instrument, its seismometer, operating continuously. Engineers have also been using the scoop on the lander’s robot arm to try to dislodge some of the dust, with only a very very limited success. If the panels are not cleared soon, however, engineers will eventually be forced to shut everything down.

InSight pauses science operations to conserve power

The science team for the InSight lander on Mars have been forced to suspend science operations because dust on the solar panels is reducing the available power.

InSight’s solar panels were producing just 27% of their energy capacity in February, when winter was arriving in Elysium Planitia. So NASA decided to start incrementally turning off different instruments on the lander. Soon the robot will go into “hibernation mode,” shutting down all functions that aren’t necessary for its survival.

By pausing its scientific operations, the lander should be able to save enough power to keep its systems warm through the frigid Martian nights, when temperatures can drop to negative-130 degrees Fahrenheit. “The amount of power available over the next few months will really be driven by the weather,” Chuck Scott, InSight’s project manager, said in a statement.

InSight is still in good condition – it’s even using its robotic arm – but the risk of a potentially fatal power failure is ever-present. If the lander’s batteries die, it might never recover.

As with the rovers Spirit and Opportunity, InSight engineers have depended on periodic strong wind events to periodically clean off the solar panels. Unfortunately, these events are somewhat random, and for the past few months none have occurred.

Note: the article at the link says that winter was arriving at InSight’s location in February, but this is incorrect. InSight sits at about 4 degrees north latitude. In February the end of winter was approaching in the northern hemisphere. More to the point, sitting at the equator you wouldn’t really expect InSight to experience much seasonal changes regardless.

It therefore seems that these issues had less to do with the seasons and much more to do with the accumulating dust on the panels.

InSight detects additional 3+ magnitude quakes on Mars

Martian quake map as seen by InSight

According to a JPL press release today, the seismometer on the Mars lander InSight detected two new 3+ magnitude quakes in March, both coming from the Cerberus Fossae region, the same region where the bulk of seismic activity has so far been pinpointed on Mars.

The map to the right was presented several weeks ago at the 52nd Lunar and Planetary conference, and could possibly include one of these two new quakes. The timing however of these March quakes is significant:

The new quakes have something else in common with InSight’s previous top seismic events, which occurred almost a full Martian year (two Earth years) ago: They occurred in the Martian northern summer. Scientists had predicted this would again be an ideal time to listen for quakes because winds would become calmer. The seismometer, called the Seismic Experiment for Interior Structure (SEIS), is sensitive enough that, even while it is covered by a dome-shaped shield to block it from wind and keep it from getting too cold, wind still causes enough vibration to obscure some marsquakes. During the past northern winter season, InSight couldn’t detect any quakes at all.

They are beginning to use the lander’s scoop to cover the seismometer and its communications tether with sand to protect both from the wind and temperature fluctuations. Once done they hope to be able to detect quakes during the entire Martian year, though this ability will be further limited by a reduction in power.

Despite the winds that have been shaking the seismometer, InSight’s solar panels remain covered with dust, and power is running lower as Mars moves away from the Sun. Energy levels are expected to improve after July, when the planet begins to approach the Sun again. Until then, the mission will successively turn off the lander’s instruments so that InSight can hibernate, waking periodically to check its health and communicate with Earth. The team hopes to keep the seismometer on for another month or two before it has to be temporarily turned off.

Quakes on Mars as seen by InSight

Martian quake map as seen by InSight

After completing its first full Martian year on the surface of the Red Planet, the scientists for the lander InSight today gave a report [pdf] of their results at this year’s annual 52nd Lunar and Planetary Science Conference, normally held in Texas but being done virtually this year out of terror of the coronavirus.

All told the lander’s seismometer has, as of just a few days ago, detected just over 500 quakes. The map to the right, showing the most distinct quakes and their locations, was adapted from a different presentation [pdf] at the conference. The numbers indicate the sols after landing when these quakes were detected.

This is essentially the region on Mars that I call volcano country. Some of the lava flood plains here are the youngest on Mars. To the east just beyond the edge of the map is the Tharsis Bulge, which holds Olympus Mons and the string of three giant volcanoes to its east. South of Cereberus Fossae but north of the yellow-colored cratered highlands is the vast Medusae Fossae Formation, the largest volcanic ash deposit on Mars.

The quakes suggest they are occurring as large blocks shift along faults, creating fissures and cracks that geologists call grabens. The long fissures of Cereberus Fossae are considered an example of grabens, so this activity suggests that shifting is still going on in the region.

In addition to outlining the location of the detected volcanoes, the presentation today summarized these other discoveries made by InSight about Mars’ interior structure:

  • The crust of Mars has likely two or three layers either 12 or 24 miles thick, with a total thickness no more than 45 miles. This is much thinner than most scientists had expected.
  • The mantle layer below the crust is estimated at about 250 to 375 miles thick, with a temperature between 1,600 to 1,700 degrees Kelvin. While quite hot, this is a cooler mantle than expected.
  • The core of Mars is somewhere between 1,100 to 1,300 miles in diameter, with a outer layer made of liquid. These results are at the high end of pre-mission expectations.

As already admitted, it was noted that the heat sensor experiment will not be able to provide the interior temperature of Mars, as its digging mole was unable to dig into the ground the 9 to 15 feet planned.

InSight: Mars’ crust is thin, and its interior is many layered with a molten core

Scientists yesterday released results from the seismometer on the Mars InSight lander that suggest that the crust of the red planet is thin and that its interior is many layered with a molten core.

[T]wo moderate quakes, at magnitude 3.7 and 3.3, have been treasure troves for the mission. Traced to Cerberus Fossae, deep fissures in the crust 1600 kilometers east of the landing site that were suspected of being seismically active, the quakes sent a one-two punch of compressive pressure (P) waves, followed by sidewinding shear (S) waves, barreling toward the lander. Some of the waves were confined to the crust; others reflected off the top of the mantle. Offsets in the travel times of the P and S waves hint at the thickness of the crust and suggest distinct layers within it, Brigitte Knapmeyer-Endrun, a seismologist at the University of Cologne, said in an AGU presentation. The top layer may reflect material ground up in the planet’s first billion years, a period of intense asteroid bombardment, says Steven Hauck, a planetary scientist at Case Western Reserve University.

At 20 or 37 kilometers thick, depending on whether the reflections accurately trace the top of the mantle, the martian crust appears to be thinner than Earth’s continental crust—a surprise. Researchers had thought that Mars, a smaller planet with less internal heat, would have built up a thicker crust, with heat escaping through limited conduction and bouts of volcanism. (Though Mars is volcanically dead today, giant volcanoes dot its surface.) A thin crust, however, might mean Mars was losing heat efficiently, recycling its early crust, rather than just building it up, perhaps through a rudimentary form of plate tectonics, Mojzsis says.

The thin crust provides a solid basis for explaining the large volcanoes and vast lava plains on the planet. Combined with the light gravity, magma would have found an easier path to the surface. Handed this knowledge, planetary geologists can now make a first stab at outlining more precisely the planet’s early volcanic history.

Update on InSight’s mole: It is now underground

InSight's mole now completely buried
Click for full image.

An update today on the mole digging tool on the Mars lander InSight has revealed that the mole appears to finally be completely buried, though it remains unclear whether its most recent digging effort had succeeded in digging downward.

We found that during the first two rounds of hammering and during the first half of the third round of hammering, the scoop went further into the sand. Since the Mole was hidden under the scoop, the penetration of the probe itself could not be observed directly.

During the hammering, the flat tether running to the probe moved considerably, but these could only be clearly identified as forward movements during the hammering on 22 August. Overall, we could estimate from the movements of the scoop that the Mole moved at most one centimetre further into the ground. It was interesting to observe that during the second half of the round of 250 hammer blows on 19 September, the scoop did not go any further, probably because it encountered duricrust. This was certainly a desired outcome, as it allowed a second Free Mole Test to be conducted. In fact, the probe continued to move according to the movements of the tether, but it could not be clearly determined that these movements brought the Mole deeper into the ground.

The image shows InSight’s arm above the filled hole, with the mole’s flat tether coming out of the ground.

They are now going to fill the hole more, and then press down with the scoop during later drilling efforts to see if this allows the mole to proceed downward. If it fails I’m not sure if there is anything else they will be able to do to get the mole to work.

InSight has buried its Mole

The Mole buried

Using the scoop on InSight’s robot arm, engineers have now successfully filled the large hole that had formed around the spacecraft’s mole, the drill that has been trying but failing to dig down about fifteen feet so that a heat sensor could measure the internal temperature of Mars.

The image to the right shows the filled hole with the mole’s communications tether snaking away. Earlier this month they used InSight’s scoop to scrape surface material into the hole, as planned in June. According to the mole’s principle investigate, Tilman Spohn,

I had estimated that the first scrape of 12 centimetres swath length would raise the bottom of the pit but leave the Mole sticking out of the sand. By the way, this was the condition for some to agree to the quite controversial ‘scratch test’. As one can see in the image from Sol 600 shown below, that estimate was not quite right. The scraping was a complete success! The scrape was much more effective than expected and the sand filled the pit almost completely. The Mole is now covered, but there is only a thin layer of sand on the back cap.

Their next step will be to use the scoop to press down on the dirt of the filled hole, with the hope this added pressure will keep the dirt pressed against the mole as it hammers downward, thus holding it place with each downward stroke.

Problem with InSight’s weather station

Engineers are troubleshooting a problem with the weather sensors on the InSight lander on Mars that has prevented them from collecting data since August 16th.

[The weather system] is in safe mode and unlikely to be reset before the end of the month while mission team members work toward a diagnosis. JPL engineers are optimistic that resetting the control computer may address the issue but need to investigate the situation further before returning the sensors to normal.

Overall InSight has turned out to be of mixed success. The seismometer has worked as planned, but the mole designed to drill the heat thermometer sixteen feet into the ground has so far failed to work, and now the weather station has shut down, though hopefully only temporarily.

Scientists make first rough estimate of Mars’ internal structure

Artist's cutaway showing theorized Martian interior
Artist’s cutaway of theorized Martian interior

Using data from InSight’s seismometer, scientists have made their first approximation of the internal structure of Mars.

The first boundary Deng and Levander measured is the divide between Mars’ crust and mantle almost 22 miles (35 kilometers) beneath the lander.

The second is a transition zone within the mantle where magnesium iron silicates undergo a geochemical change. Above the zone, the elements form a mineral called olivine, and beneath it, heat and pressure compress them into a new mineral called wadsleyite. Known as the olivine-wadsleyite transition, this zone was found 690-727 miles (1,110-1,170 kilometers) beneath InSight. “The temperature at the olivine-wadsleyite transition is an important key to building thermal models of Mars,” Deng said. “From the depth of the transition, we can easily calculate the pressure, and with that, we can derive the temperature.”

The third boundary he and Levander measured is the border between Mars’ mantle and its iron-rich core, which they found about 945-994 miles (1,520-1,600 kilometers) beneath the lander. Better understanding this boundary “can provide information about the planet’s development from both a chemical and thermal point of view,” Deng said.

Because they only have one seismometer on the planet, this approximation has a great deal of uncertainty. Only when we have multiple such seismic instruments, scattered across the entire Martian globe, will scientists be able to hone their models more accurate of the planet’s interior.

Seismic signal from recent Martian impact detected by InSight?

According to a science paper released today, a small impact that occurred about 25 miles south from the InSight lander between February 21st and April 6, 2019 might have been detected by the spacecraft’s seismometer.

From the paper’s abstract:

During this time period, three seismic events were identified in InSight data. We derive expected seismic signal characteristics and use them to evaluate each of the seismic events. However, none of them can definitively be associated with this source. Atmospheric perturbations are generally expected to be generated during impacts; however, in this case, no signal could be identified as related to the known impact. Using scaling relationships based on the terrestrial and lunar analogs and numerical modeling, we predict the amplitude, peak frequency, and duration of the seismic signal that would have emanated from this impact. The predicted amplitude falls near the lowest levels of the measured seismometer noise for the predicted frequency. Hence it is not surprising this impact event was not positively identified in the seismic data.

Based on this data, they now think they will only be able to detect about two impacts per year with InSight’s seismometer, a decrease from the previous estimate of as many as ten.

InSight’s mole is bouncing again

Plan of action for InSight's mole

The engineering team for InSight’s German-built digging tool, dubbed the mole, yesterday reported that it is once again no longer driving into the ground.

Previously they had been able to make progress by having InSight’s scoop press down on the mole. Once the top of the mole however was below ground, the scoop could no longer provide that support, and at that point the mole began bouncing again with each hammer-stroke, the surrounding Martian dirt unable to provide the friction to hold the mole down.

As shown by the illustration above, they are now going to try using the scoop to fill the hole and then use the scoop to press down on the dirt, with the hope this will provide the structural friction required to hold the mole in place after each hammer stroke. This effort will take time, and will prevent the scoop from doing its other work. They are therefore taking a pause until August before beginning the hole-filling operation.

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