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.

Quakes by InSight indicate Mars’ interior is active

Cerberus Fossae

The first seismic results from InSight’s seismometer now show that the interior of Mars is active, with regular moderately-sized quakes.

The Seismic Experiment for Interior Structure (SEIS) instrument – a seismometer developed by an international consortium under the leadership of the French space agency CNES – recorded a total of 174 seismic events between February and September 2019. Twenty of these marsquakes had a magnitude of between three and four. Quakes of this intensity correspond to weak seismic activity of the kind that occurs repeatedly on Earth in the middle of continental plates, for example in Germany on the southern edge of the Swabian Jura hills.

Although only one measurement station is available, models of wave propagation in the Martian soil have been used to determine the probable source of two of these quakes. It is located in the Cerberus Fossae region, a young volcanic area approximately 1700 kilometres east of the landing site.

Cerberus Fossae is a land of cracks and linear depressions located between the giant volcanoes, Elysium Mons to the north and Olympus Mons to the east. It is believed those fissures were caused by the rise of those volcanoes, stretching the crust and cracking it.

This new data from InSight strengthens this theory.

Engineers to use InSight’s scoop to help digging process

Insight’s engineers, having failed to get its mole pile driver to dig down as planned, now plan to use the lander’s scoop to push on the mole in the hope this will prevent it from popping up with each hammer drive.

[T]he mole is a 16-inch-long (40-centimeter-long) spike equipped with an internal hammering mechanism. While burrowing into the soil, it is designed to drag with it a ribbonlike tether that extends from the spacecraft. Temperature sensors are embedded along the tether to measure heat coming deep from within the planet’s interior.

…The team has avoided pushing on the back cap [at the top of the mole] until now to avoid any potential damage to the tether.

It appears to me that they are running out of options. This new attempt carries risks. It could damage the tether required to obtain underground temperature readings, the prime purpose of the experiment. However, if they don’t get the tether into the ground, this will also prevent the experiment from functioning. Thus, this attempt could essentially be a Hail Mary pass, gambling all on one last all-or-nothing gambit.

New InSight image of mole shows collapse of hole

View of InSight drill hole
Click for full movie.

The InSight science image has lifted the lander’s rover arm off the drill hole and taken a new series of images in an effort to discover what caused the mole to pop out during its most recent drilling effort.

The image to the right, cropped to post here, was the first in a short movie made from all the images taken over the course of a day. The sequence shows the change in shadows, which helps define the situation in the hole.

This image however I think tells all. It shows that the walls of the hole have collapsed all around the mole, widening it further. It also shows that, once the mole popped out to lean sideways against the left wall, much of that material then fell into the hole, refilling it. These facts are very evident when today’s image is compared with this image from October, taken prior to the most recent drilling effort. The hole has become much wider, there is more material inside it, and the mole is now much farther out.

All these facts bode ill for the mole ever succeeding in drilling down the planned fifteen or so feet to insert a heat probe into the interior of Mars in order to take the first ever measure of the planet’s interior.

An overall assessment of this NASA mission is not very positive. The contribution from its international partners is especially bad. The mission was launched two years late because the French effort to build the seismometer failed. NASA had to subsequently give the job to JPL to get it done. Now the heat sensor is a failure, because the German-built mole has failed to get the heat sensor where it needs to be.

The seismometer and heat sensor were InSight’s only science instruments. This means that we will likely only get results from one.

InSight’s mole has popped out of its hole

InSight's mole, out of the ground
Click for full image.

In a setback for its renewed digging effort, the mole drill on InSight has apparently bounced out of its drilled hole during the most recent drilling, soon after engineers had increased the rate of hammer strokes.

The image to the right shows the mole, the white cylinder on the left, with the scoop of the robot arm mostly covering the hole in its effort to pin the mole in position.

“While digging this weekend the mole backed about halfway out of the ground,” the mission announced via a pair of tweets Oct. 27. “Preliminary assessment points to unexpected soil properties as the main reason.”

…The mission added that one possibility is soil is falling in front of the mole, filling the hole. “Team continues to look over the data and will have a plan in the next few days.”

Without question the alien and fluffy properties of the soil appears to be the problem. Based on how the mole is leaning, I wonder if the left wall of the hole began to widen and collapse, as had the rest of the hole during initial drilling, thus defeating the purpose of the robot arm’s effort to pin the mole in place.

InSight’s digging problems reveal the alienness of Mars’ soil

Even as InSight’s mole shaft driller shows signs of working, its difficulties in digging into the Martian soil has revealed how truly alien that soil is from what we normally expect.

[U]nlike typical holes dug here on Earth, the one excavated by InSight’s mole has no lip of dirt around its rim, Hoffman said. “Where did the soil go?” he said. “Basically, it got pounded back into the ground, so it seems like it’s very cohesive, even though it’s very dusty.”

And this is a weird combination of characteristics, strongly suggesting that Mars dirt is alien in more ways than one. “The soil properties are very different than anything we’ve ever seen on Earth, which is already a very interesting result,” Hoffman said.

That the soil of Mars is alien should not be a surprise. The planet’s dusty nature, combined with its light gravity and lack of life, practically guaranteed that the soil would have different and unexpected properties. What is disturbing is that it appears this likelihood was not considered in the slightest by the German engineers who designed the mole for digging.

InSight’s mole digs an inch

The InSight science team today tweeted that their attempt to use the lander’s robot arm to help the mole push downward in its effort to insert a heat sensor fifteen feet into the Martian interior has resulted in a gain of about an inch or three centimeters.

This success, small as it seems, is important in that it proves that the reason the drill had been stopped penetrating downward was not because of the presence of a rock, but because the drill hole had become so wide that the drill no longer had side friction to hold it in place. They are now using the arm to give the mole that friction.

The goal was to insert to heat sensor five meters or about sixteen feet into the ground. They are presently a little over a foot down. If this effort has really succeeded, they can then proceed to drill the remaining distance.

One issue however is whether the unexpected weak and porous nature of the soil, which allowed the hole to become so wide, might affect any data produced by the heat sensor. This is presently unknown, but it is a significant question that the scientists involved must ask. If the sensor ends up inside a very wide shaft that allows the surface environment to reach the sensor then it will not really be measuring the temperature of the Martian interior.

InSight robot arm to help mole dig

Mole in hole, with robot arm and scoop above
Click for full image.

In their effort to solve the issues that have prevented InSight’s mole from penetrating more than fourteen inches into the ground on Mars, engineers now plan to use the scoop on the robot arm to “pin” the mole up against one wall of the hole so that it will have the friction necessary to drill downward.

The image to the right, cropped and reduced to post here, illustrates what they have been doing and what they will do. Previously the hole was much larger, which prevented the mole from moving downward because it needed the friction from the material around it to hold it in place after each hammer action. (Think of pounding a nail into a wooden board: The nail is gripped tightly by the wood around it as it goes down, so that after each hit it goes further in.)

Since June they have been using the arm and scoop to fill in the hole around the mole. Now I think they intend to bring the scoop around to the mole’s left side, as shown in the image, and pin it upright against the right wall of the hole. When it resumes hammer-drilling they hope both the wall and the scoop will provide enough friction for the mole to drill downward.

The sounds of Mars

The InSight seismometer team today issued an update of their results since the instrument began recording quakes on Mars in February.

But after the seismometer was set down by InSight’s robotic arm, Mars seemed shy. It didn’t produce its first rumbling until this past April, and this first quake turned out to be an odd duck. It had a surprisingly high-frequency seismic signal compared to what the science team has heard since then. Out of more than 100 events detected to date, about 21 are strongly considered to be quakes. The remainder could be quakes as well, but the science team hasn’t ruled out other causes.

The press release provides audio for many of these detections, including two 3.3+ earthquakes as well as a strange sequence of what they call “dinks and donks” that appear to occur each evening as the seismometer adjusts to night-time temperatures.

So far the data suggests that Mars’ interior is a relatively quiet place, compared to Earth.

Update on effort to save heat probe on InSight

Link here. The article, written in late August by one of the German scientists in charge of the heat probe on the Mars lander InSight, gives a detailed look at the effort to figure out what is blocking the Mole, the digging tool designed to pound the heat probe as much as 15 feet into the ground.

They had discovered previously is that the ground had collapsed around the drill shaft, creating a very wide hole. The Mole however needed the friction caused by the surrounding dirt to push downward, and thus didn’t have it.

They have since used InSight’s scoop at the end of the robot arm to push at the ground around the hole in an effort to fill the hole. As of mid-August this has managed to fill the hole about half way.

This report was written on August 27, just before contact with Mars was lost for two weeks because the Sun had moved between the Earth and Mars. Communications have now resumed, so I expect they will also resume their efforts to fill the hole enough that they might then try to resume the digging effort.

Hat tip to Doug Messier of Parabolic Arc, who by the way is right now running his annual fund-raising drive for the website. Please consider donating.

China successfully tests navigation in space using pulsars

Using the X-ray space telescope Insight it launched in 2017, China has successfully tested an autonomous navigation system using pulsars.

The time interval of two adjacent pulses emitted by the pulsar is constant. If a spacecraft moves toward the pulsar, the received pulse interval will be shortened, and vise versa. Thus the observed pulse profile will change as the spacecraft moves in space. The relative arrival times of pulses also indicate the relative position of the spacecraft with respect to the pulsar. Therefore, by analyzing the characteristics of the pulsar signals received by the spacecraft, the three-dimensional position and velocity of the spacecraft can be determined, Zheng explained.

From Aug. 31 to Sept. 5, 2017, Insight observed the Crab pulsar for about five days to test the feasibility of pulsar navigation. The research team had also proposed an algorithm for X-ray pulsar navigation, according to Zhang Shuangnan, lead scientist of the Insight space telescope.

The research team further improved the algorithm and applied it in the processing of the observation data of the three detectors onboard Insight. The satellite’s orbit was determined successfully, with the positioning accuracy within 10 km, comparable to that of a similar experiment conducted on the International Space Station, Zhang said.

This is not the first such test. U.S. scientists did something similar using an X-ray telescope on ISS in 2017.

Update on effort to resume drilling of heat probe on InSight

Link here. It appears InSight’s camera cannot see the hammer drill, called “the mole,” that pushes the heat probe down, and to get a look and assess the problem they are going to use InSight’s robot arm to remove the equipment in the way.

The lifting sequence will begin in late June, with the arm grasping the support structure (InSight conducted some test movements recently). Over the course of a week, the arm will lift the structure in three steps, taking images and returning them so that engineers can make sure the mole isn’t being pulled out of the ground while the structure is moved. If removed from the soil, the mole can’t go back in.

They also have a theory as to what has stopped the drilling.

Team members now believe the most likely cause is an unexpected lack of friction in the soil around InSight – something very different from soil seen on other parts of Mars. The mole is designed so that loose soil flows around it, adding friction that works against its recoil, allowing it to dig. Without enough friction, it will bounce in place.

They can’t see it, as designed? It depends on the soil for friction? I am very puzzled at these design decisions.

First Marsquake recorded by InSight?

The InSight science team has announced that they think they have detected their first Mars quake, though it was too small to provide much information about the Martian interior.

The Martian surface is extremely quiet, allowing SEIS, InSight’s specially designed seismometer, to pick up faint rumbles. In contrast, Earth’s surface is quivering constantly from seismic noise created by oceans and weather. An event of this size in Southern California would be lost among dozens of tiny crackles that occur every day.

“The Martian Sol 128 event is exciting because its size and longer duration fit the profile of moonquakes detected on the lunar surface during the Apollo missions,” said Lori Glaze, Planetary Science Division director at NASA Headquarters.

…Three other seismic signals occurred on March 14 (Sol 105), April 10 (Sol 132) and April 11 (Sol 133). Detected by SEIS’ more sensitive Very Broad Band sensors, these signals were even smaller than the Sol 128 event and more ambiguous in origin. The team will continue to study these events to try to determine their cause.

The data so far suggests is that Mars is far quieter than Earth geologically, but any conclusions at this point would be premature.

Future of InSight’s heat probe dim

Blocked after drilling down only one foot instead of fifteen, engineers are increasingly worried that they will not be able to get InSight’s heat probe past whatever is blocking to so it can begin getting data of Mars’s inner thermal environment.

They are considering a bunch of options, including using InSight’s robot arm to either give the probe a nudge to help it get past the obstruction, or even use the arm to push the probe.

None of the options are encouraging it seems.

A gathering of dust devils

Dust devil tracks
Click for full resolution image.

A bunch of cool images! The European Space Agency (ESA) today released more than a dozen Martian images taken by the camera on its Trace Gas Orbiter spacecraft.

In addition to a snapshot of InSight and its landing area, “The images selected include detailed views of layered deposits in the polar regions, the dynamic nature of Mars dunes, and the surface effects of converging dust devils.” The release also included images showing details of two of Mars’ giant volcanoes, Olympus Mons and Ascraeus Mons.

The image I have highlighted to the right, reduced to post here, shows a spot on Mars where for some unknown reason dust devils love to congregate.

This mysterious pattern sits on the crest of a ridge, and is thought to be the result of dust devil activity – essentially the convergence of hundreds or maybe even thousands of smaller martian tornadoes.

Below is a side-by-side comparison of this image (on the right) with a Mars Reconnaissance Orbiter (MRO) image taken in 2009 (on the left).
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InSight hits a rock

Engineers have called a pause in InSight’s drilling operation to insert a heat sensor as much as 16 feet into the Martian soil because it appears the drill has hit a large obstruction.

It penetrated to a depth between 18cm and 50cm into the Martian soil with 4,000 hammer blows over a period of four hours, explained Tilman Spohn, HP3’s principal investigator from the German space agency (DLR). “On its way into the depths, the mole seems to have hit a stone, tilted about 15 degrees and pushed it aside or passed it,” he added. “The mole then worked its way up against another stone at an advanced depth until the planned four-hour operating time of the first sequence expired.”

Prof Spohn said there would now be a break in operations of two weeks while the situation was assessed.

When these facts were first reported on March 1st, the press release did not make it clear at that time that the hammer drill was actually blocked. If it cannot drill down further, this will put a crimp in the heat sensor’s ability to measure Mars’s internal temperature. Right now it is only about a foot down, which on Earth would still have it influenced by surface temperatures.

InSight’s heat sensor begins drilling down

The German-made heat sensor hammer that the U.S. lander InSight placed on the Martian surface has begun hammering its heat sensor into the ground.

On 28 February 2019, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) ‘Mole’ fully automatically hammered its way into the Martian subsurface for the first time. In a first step, it penetrated to a depth between 18 and 50 centimetres [7 to 19 inches] into the Martian soil with 4000 hammer blows over a period of four hours. “On its way into the depths, the mole seems to have hit a stone, tilted about 15 degrees and pushed it aside or passed it,” reports Tilman Spohn, Principal Investigator of the HP3 experiment. “The Mole then worked its way up against another stone at an advanced depth until the planned four-hour operating time of the first sequence expired. Tests on Earth showed that the rod-shaped penetrometer is able to push smaller stones to the side, which is very time-consuming.

They will let the hammer cool down for a few days, and then resume hammering. If all goes well, they hope to get as much as 16 feet down.

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