InSight Surface Operations, 26 Nov 2018- 21 Dec 2022 Options

[serpens]

In this we are assuming that the void is due to soil properties. There is the possibility that the void was created by vibrating in place if the mole encountered a large rock similar to that exposed by InSight's exhaust.

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[tanjent]

I don't see how any amount of vibration in place could produce a void in the complete absence of adhesion between the soil particles. If there is a subsurface rock like the one pictured - too big to circumvent and too solid to punch through, then there is no path to success in this location. Transplanting the probe will have to be considered. Digging a new hole elsewhere initially as a source of loose fill (assuming that the shape of the scoop and the force it can exert allow this) might make transplantation possible as a last resort.

[James Sorenson]

If there is a subsurface rock like the one pictured - too big to circumvent and too solid to punch through, then there is no path to success in this location. Transplanting the probe will have to be considered.

As a last resort in that event, there is one option that I can think of to try and extract the mole which would be extremely dangerous to the mole, but would be better than giving up completely. Something that could first be tested of coarse in the test bed to see if it could be possible to do. There are three things in our favor, We have a long arm that can Kinematically move linearly in three axis of motion, we have a 5 fingered grapple and the mole is a cylinder. The machinist in me is talking here like how a lathe chuck holds round bar stock, how about try and grab the top of the mole with the grapple with enough closing force to to grasp it and try pulling it out? The arm and grapple then could vertically position it to a new location. Once positioned above a new location, the arm could lower the mole with the tip of it just touching the surface. After this is done, the mole could start hammering with the arm feeding down with it at the same rate as the hammer cycle. Once enough of the mole is in the subsurface and not at risk of toppling over, the grapple can release slightly but still help guide it down. The grapple is on a lanyard, so really guiding it with the grapple during this step might not work well, so really just releasing it completely would be better.

The biggest issue in all of this is that delicate flex print cable, grabbing it heavily risks hitting or severing it, but if the cable could fit in the space between two fingers, could that be possible? Also since the mole is not currently vertical but tilted, grabbing it would be a challenge unless the scoop could first be used to try and tug on one side to straighten it out. If that could be done, the only obstacles would be getting around that cable with the grapple and clamping around it with enough force to hold it and not slip. Anyone know what the clamping force the grapple has? I know it uses paraffin wax actuators which obviously have allowed the grapple to lift the weight of the science instruments to the surface. In a video that I had seen, one engineer had said when it closes around a pin and the wax cools, the fingers lock around the pin which prevents any inadvertent release. How about that for thinking outside the box?

[atomoid]

Expected to hear something on progress of the mole by now but the arm continues snoozing as if waiting for something.
Otherwise, interesting preliminary assertions on other fronts are coming out nonetheless, as Nat'l Geographic quipped "...magnetic machinations of Mars are marvelously mad"

[Steve G]

As a last resort in that event, there is one option that I can think of to try and extract the mole which would be extremely dangerous to the mole, but would be better than giving up completely. Something that could first be tested of coarse in the test bed to see if it could be possible to do. There are three things in our favor, We have a long arm that can Kinematically move linearly in three axis of motion, we have a 5 fingered grapple and the mole is a cylinder. The machinist in me is talking here like how a lathe chuck holds round bar stock, how about try and grab the top of the mole with the grapple with enough closing force to to grasp it and try pulling it out? The arm and grapple then could vertically position it to a new location. Once positioned above a new location, the arm could lower the mole with the tip of it just touching the surface. After this is done, the mole could start hammering with the arm feeding down with it at the same rate as the hammer cycle. Once enough of the mole is in the subsurface and not at risk of toppling over, the grapple can release slightly but still help guide it down. The grapple is on a lanyard, so really guiding it with the grapple during this step might not work well, so really just releasing it completely would be better.

The biggest issue in all of this is that delicate flex print cable, grabbing it heavily risks hitting or severing it, but if the cable could fit in the space between two fingers, could that be possible? Also since the mole is not currently vertical but tilted, grabbing it would be a challenge unless the scoop could first be used to try and tug on one side to straighten it out. If that could be done, the only obstacles would be getting around that cable with the grapple and clamping around it with enough force to hold it and not slip. Anyone know what the clamping force the grapple has? I know it uses paraffin wax actuators which obviously have allowed the grapple to lift the weight of the science instruments to the surface. In a video that I had seen, one engineer had said when it closes around a pin and the wax cools, the fingers lock around the pin which prevents any inadvertent release. How about that for thinking outside the box?

I just wonder how far will they go before they give up. If all appears lost, will they try things as radical as that? Or backfilling the hole, pack it down, and even put the skoop on top of the probe itself to force it down? Like, how far would they take this, and what would be the minimum depth to get any usable science?

[PaulH51]

..magnetic machinations of Mars are marvelously mad"

Interesting: Anyone found the abstract for this that's not behind a paywall / login?

[tanjent]

As a spectator, I'd rather see the mole team try something risky than simply give up. But for institutional reasons this will be difficult. I guess the decision would have to be made collectively, to avoid one person's becoming the scapegoat for the failed experiment if they end up breaking the mole. Also, they would need to apply for a lot more DSN time to manage a hail-Mary final attempt, and without a high probability of success the application might not get very far. Likewise for other resources like personnel costs.

If the mole is to be written off, is there anything that can be done to further clarify what went wrong? Any way to increase the chance that a future attempt will succeed?

[stevesliva]

This is the first I've heard of a magnetometer on Insight. Which investigation is this a part of? SEIS?

The nat geo article is tough to get to... even logging in, I had to click through their frontpage and then it still said it was one of my 5 free articles that month. The gist there is: #1 the surface field is stronger than predicted from orbit, #2 there are fluctuations at local midnight that might be a sort of atmospheric tail in the solar wind, and getting MAVEN overhead at midnight is something they'll try, and #3 there is an electrically conductive layer at indeterminate depth that could be watery.

[PaulH51]

This is the first I've heard of a magnetometer on Insight. Which investigation is this a part of? SEIS?

InSight carries a suite of environmental-monitoring instruments, called the Auxiliary Payload Sensor Subsystem (APSS), to measure the local magnetic field, wind, and atmospheric temperature and pressure. The primary reason for including these instruments in the mission's payload is to aid interpretation of seismometer data by tracking changes in the magnetic field or atmosphere that could cause ground movement or sensor readings that might otherwise be mistaken for a seismic event. However, they can also serve on their own for other Mars science investigations.

InSight's magnetometer will be the first ever used on the surface of Mars. Researchers will use it to investigate variations in the magnetic field, which may be induced at the surface by the variations resulting from interaction of the solar wind with Mars' ionosphere. Effects of the planet's metallic core on the induced magnetic field at the surface could provide information about the size of the core.

The University of California, Los Angeles, provided InSight's fluxgate magnetometer. UCLA has previously provided magnetometers for other NASA missions, including the Galileo mission to Jupiter and the Space Technology 5 mission. The instrument can determine both the magnitude and direction of the local magnetic field.

Source: https://www.jpl.nasa.gov/news/press_kits/in...sion/science/#7

[antipode]

Many of the Insight conference abstracts are here:

https://meetingorganizer.copernicus.org/EPS...019/orals/34053

P

[PaulH51]

Many of the Insight conference abstracts are here:
https://meetingorganizer.copernicus.org/EPS...019/orals/34053

Many thanks

[JRehling]

If the mole is to be written off, is there anything that can be done to further clarify what went wrong? Any way to increase the chance that a future attempt will succeed?

I mentioned way upthread that there is a poor cumulative track record for the success of digging and subsurface probes on the Moon and Mars. Apollo struggled with this multiple times even given repeated opportunities and humans + problem solving present. The mechanical properties of regolith are varied and not perfectly understood. It's not clear that any particular test process will duplicate mission conditions. Existing legacy technology used for digging and boring on Earth uses mass extravagantly, and can't be adapted to this.

My own non-mechanical-engineer musing has thought about something like this: One or more strong but non-metallic spears that separate from the lander at altitude, drop point-down and impact the surface at high velocity. A spear could have non-mobile thermometers at various depths up and down its length, and transmit temperatures to the lander. If any spear survived, you would get your data.

That said, the last time something somewhat like this was attempted, it failed.

[HSchirmer]

...
My own non-mechanical-engineer musing has thought about something like this: One or more strong but non-metallic spears that separate from the lander at altitude, drop point-down and impact the surface at high velocity. A spear could have non-mobile thermometers at various depths up and down its length, and transmit temperatures to the lander. If any spear survived, you would get your data.

That said, the last time something somewhat like this was attempted, it failed.

I think I mentioned this somewhere up-thread, but there are extremely high-G sensors for US bunker-buster munitions.
These are part of smart-fuses that are designed to survive penetrating several meters of reinforced concrete, detect a void and then detonate.

One idea - most landers have some sort of ballast, make that ballast out of tungsten flechettes.
Release the flechettes into the landing ellipse, then let the rover check the newly drilled holes for readings.

[MahFL]

I just wonder how far will they go before they give up. If all appears lost, will they try things as radical as that? Or backfilling the hole, pack it down, and even put the skoop on top of the probe itself to force it down? Like, how far would they take this, and what would be the minimum depth to get any usable science?

The worse case minimum depth is 3m. At that depth it will take a lot longer to complete the experiment.

[abalone]

One idea - most landers have some sort of ballast, make that ballast out of tungsten flechettes.
Release the flechettes into the landing ellipse, then let the rover check the newly drilled holes for readings.

I think that the ballast weights land a long way for the craft landing zone, that is probably why they haven't done that yet