Is it my imagination, or does it look like there is actually more dust on the lens after the cover was removed?

It does appear to be the case. I wonder if there's a static charge or such occurring?
For a camera with a (removed) lens cover, there's quite a bit of dust!
Here a quick animation showing the two frames so far - Sol4, 12:53:51 PM vs 13:27:07 PM

Click to view attachment

I decided not to wait any longer for Mars' dust devils mercy and personally cleaned up the lens a bit





Also below some "upright" perspective

Great work!

If static charge is a problem attracting particles, maybe future lens designs for landing missions would include an electrically conductive lens coating (atomically thin metal and organics are transparent)? Or is the entire craft charged with very slow discharge through feet?

Very nicely done, Station!

Re static charge, it's of course too early to tell if this is happening or not. Never seemed to be a problem for cams on other landed spacecraft, though they also didn't land dead square in dustbowls.

If that is what's going on here then I'd expect it the charge to gradually dissipate over time since the lander is in contact with the surface and all of InSight's components are electrically bonded with each other to form a reference ground plane, like any other aerospace vehicle.

I asked Justin Maki what is happening to the images on their way to the website. He said:

Another interesting bit of context is the recent end of the massive dust storm. Maybe dust accumulates charge during such events and tends to lose it over subsequent months and years. There is research supporting the occurrence of lightning in martian dust storms. There was, I think, at least one martian year in every other cases between a major dust storm and the other seven successful landings (2001 until the MERs landed being just over a martian year). In fact, the possibility of an electrical discharge killing the Soviet Mars 3 lander has previously been raised, and the Mars 2 lander failed for yet-unknown reasons. Those entries happened before the 1971 dust storm had ended.

Those clumps of dust may just be a clue as to what happened to the Soviet missions in 1971.

There was a Sky and Telescope article about dust storms and static charge-
Dust Storm Electricity Might Forge Perchlorates on Mars - https://www.skyandtelescope.com/astronomy-n...orates-on-mars/

Which is based on a research paper-
Forming perchlorates on Mars through plasma chemistry during dust events - https://www.sciencedirect.com/science/artic...gcid=rss_sd_all

Curiously, perchlorate enhances dry conductivity and is used as a food additive to help dissipate static charge buildup on plastic and cardboard food containers (i.e. your Cheerios don't stick to the plastic bag)

It is a bit ironic that Humanity put a lander on Mars but didn't manage to give it a dust cover that keeps dust out... Anyway, this mission is not about the views. The images are perfectly serviceable for putting the seismometer and mole on the ground.

It has been explained in this thread how the camera and lens cap was designed and why. If you have good ideas, I suggest click on this link: https://www.jpl.nasa.gov/opportunities/

Paolo

The apparent descent thruster scour marks seem to have exhumed a lot of soil around the rock, which itself appears to be almost perfectly placed that it could focus a blowback of dust back up in the direction of the ICC.

Good point about the rock!

Phil

Emily quotes Justin Maki above as saying : Once the camera covers are opened ...
So maybe the dust specks are on the cover only, not on the lens?

The ICC cover has been opened. The current dust is on the lens.

It will probably dissipate with time. It has already begun to in just the single sol since it was deployed.

A new image is down.

https://mars.nasa.gov/insight/multimedia/ra...mission=insight

Comparing the sol 5 ICC image with sol 4 (animated GIF) shows some dust reduction on the lens
Click to view attachment

It's great that dust is flying off, but until the situation stabilizes, flat fielding will be impossible!

Complaints about dust on images aside, I'd like to point out that when it comes to the purpose for which this camera was put on the spacecraft -- imaging the foreground to guide placement of instruments -- the dust on the lens does not matter at all. The foreground is totally clear enough to guide instrument placement. "Pretty" is desirable for outreach but unnecessary to the accomplishment of mission goals.

Let's hope for some good wind puffs to make our view clearer, but there's zero problem here for the mission.

I'm actually really intrigued by how deep the footpad has sunk. That's fascinating. I don't think any other footpad on any other mission has done that. Is the soil compressible? Was it blown away, undermined, during the final moments of landing? How did that happen?

am I the only one who sees linear features (thruster-blown dust?) in the area between the leg and the big pebble?

I think that's correct about other lander footpads not sinking as deeply. But some Rover wheels did go deep, doubtless exacerbated by their rotation.

Found a graphic that suggests landing rockets create areas with up to 100k+ Pa of pressure,
that's about 14.6 psi overpressure, should be enough to blow small rocks and stones away.


Anybody know how much hydrazine propellant is left over?
It might be interesting to engage a 1-Newton attitude control thruster and see if that blows sand around.
Hmm, how about using more and more powerful rockets to characterize the range of surface dust-sand-pebble-rock sizes... Seems that the 3 types of thrusters are variable, ~.2 to 1 Newton, ~12-30 Newtons, and ~100-300 Newtons.

Heck, a scoop is nice for trenching, but you've potentially got a 10kPa hydrazine-powered leaf blower to remove the overburden (think Jacque Cousteau vacuuming away the sand to reveal the wreck, just done with rocket exhaust).

Dear Emily, for your info, footpad #2 of Viking Lander 1 sunk at landing and was buried beneath a cover of loose Martian soil. It sunk about 12 cm, and fine-grained soil slumped into the depression of the footpad and over it
Click to view attachment

Cool, thanks!

A scary thought just came to mind : what if the lander landed on quicksand? It's ridiculous, right?

Pretty much. "Real" quicksand requires liquid water to keep the sand in suspension. Not going to happen on Mars on the surface. I suppose super-fluffy dust or ash is possible, but hasn't been so far. Enough to get a rover caught, but not Neverending Story disappearing beneath the sands.

Nope, not ridiculous at all. In hindsight, just unlikely.

The Surveyor landings on the Moon were (in part) to make sure the lunar seas were really cooled lava flows that you could land on, not tens of meters of uncompacted or electrostatically levitated dust that you'd sink into.
Turns out there ARE tens of meters of lunar dust, but it's compacted and mixed with larger grains so that it can support the weight.

There are some weird bodies that appear to have "quicksand" surfaces, i.e. just dust without a solid surface.
One is Saturn's egg-shaped moon Methone, which seems to be just dust.
Others are the "dust ponds on asteroids, which seem to accumulate dust in depressions,
https://www.sciencemag.org/news/2001/09/dusty-ponds-space
or at the low gravity point between contact binaries.

Now, for trying to answer the question- the problem wouldn't be "quicksand" but "deep loose dust"-
I think the answer would depend on what triggers the landing rockets to shut off.
If the landing rocket shutdown is triggered by foot-probes AND the dust has no bearing strength, (i.e. acts like a fluid) then the rockets don't get a shut-off signal and continue to fire as the lander approaches the dust.
I'll guess the lander has a fail-safe "when in doubt, hover, don't crash" routine so it should hover in place until it touches ground, that should be time enough to blow out the loose dust?
If the landing rocket shutoff is triggered by a proximity radar, then the loose dust probably reflects enough to fool the lander into thinking it's approaching solid ground, and the lander sinks into the dust.

Regardless of all the data from orbiters there is a degree of luck involved in landing. Curiosity did a hole in one in a small crater. Imagine if she had bounced to a stop in the middle of Endurance crater's central dune field.

That’s not how the landing works. At a certain altitude you’ll hear the EDL commentator say ‘constant velocity phase’’. At that altitude the radar starts to become unreliable and the spacecraft continues to descend at a constant velocity using the IMU. Once the three landing legs detect a touchdown the engines shut off.

The thermal inertia of this landing site precludes the sort of light fluffy dust that one might interpret as ‘quicksand’

"Curiosity did a hole in one in a small crater."

Opportunity! Curiosity landed in gigantic crater.

Phil

Clarke's (pre-Surveyor) classic immediately comes to mind

Yes, at least with a rover, you're inherently mobile and get some chance to change location;
with a lander like Viking, Phoenix or Insight, you're stuck with the place you get.

Unless, well, you do something crazy, like rethinking the lander footpads

and changing them over to passive caster wheels.

So, when you're just out of reach of that perfect rock, 'burp' the attitude control thrusters
and you've got a chance to scoot the lander over to where you want to be. You won't have much range,
but heck, fine-tuning the lander position by a meter(s?) could be really useful in an appropriate situation.
You were never going to use that left over hydrazine anyway...

Back in 2009 when selecting the soil simulant for Spirit extrication testing, we started with plain food grade diatomaceous earth and tested the compactness with a suitable weight. I remember the first test resulted in the weight sinking completely into the simulant and disappeared from sight. We had to add quite a bit of clay to have some cohesion and avoid full full sinkage. The mix of clay and DE had to be mixed after a couple of days since it was getting compacted by Earths gravity over time. I'm not sure how InSight ground pressure compares to MER/MSL wheels.

Paolo

Always a chance of that 1 or 2 % end of mission landing...

How much hydrazine was left in InSight's tanks after landing and what happens to it? With Curiosity, the skycrane was useful for long range disposal of the unspent (very toxic!) propellant. I don't like the idea of this volatile stuff just sitting there in the tanks for years... can our resident propellant expert enlighten us a tad?

Propguy will surely know more about this.
my guess: after landing, the propulsion system is "safed" by venting all the helium pressurization gas and only hydrazine remains. without helium, it's no longer possible to operate the thrusters. this is how the Surveyor lunar landers operated, IIRC
just my guess. I am willing to be corrected

Great guess Paolo! After landing (about 1 minute afterwards) one final pyrovalve was fired that vented the propellant and pressurant tanks. That plan was copied from Phoenix (and I did not know till today that Surveyor did that too). Best estimate is that there is ~20 kg of remaining propellant on InSight (very close to what Phoenix had after landing too). That propellant is very unusable though in that once landed all propulsion heaters are turned off to reduce power draw on the vehicle. It is unlikely too that we would have the heater power level required to keep the tanks warm in the cold CO2 atmosphere (much higher cooling rate via convection, and the MLI would be mostly useless while landed). So the propellant is very frozen by now. The tanks were vented so if the tanks or lines go through a thaw period (above 2 C, which is possible near the equator) and rupture a line (the hydrazine contracts when frozen but will expand when melting and that could rupture the lines) the resulting liquid will ooze out due to no driving pressure (vs. a spray if we had not vented). No worry about hydrazine toxicity (no life, plus there is some debate about the carcinogenic classification of hydrazine), but it is very corrosive too and is a great solvent for polyamids including Kapton. Thus it can severely damage wiring and heaters, so we do not want a spray. We have always joked to the program that if they did not freeze the prop we could take off again and find a better landing site. Of course that is not an option (all guidance hardware and essentially anything not directly related to landed ops was also powered off at landing).

About making a flatfield image of the ICC, how about using the arm, putting it very close to the lens so it appears out of focus, and cover the whole field of view. Then, taking pictures, we will having a kinda homogeneous foreground, and we could make a flatfield.

I don't know if it's possible, just an idea though.

It's really hard to flatfield fisheyes. I doubt you could get the arm nearly close enough to the lens - the fov is so crazy wide that the image wouldn't be homogeneous.

Guess the next generation mars lander software might include "hover and hazard avoidance"?

Now that we've used ancillary craft, the cube sats tagging along and relaying data,
I wonder about ancillary sensors deployed during descent?
Adapt "smart skeet" cluster bomb technology to identify potential science targets and then fire a round of science probes.


~25 kg for IR/laser targeted probes to pick the top 4 targets over ~12,000 square meters.

I recall seeing a NASA Announcement of Opportunity several years ago for investigating turning the weights jettisoned during the landing sequence into full-fledged probes (For missions that needs an offset center of mass for lift). Can't seem to find it now though. Anyone else have better luck?

Takeoff? Crazy. On the other hand, venting the pressurant across the dusty camera lens... Or solar panels...

Interesting, I would have thought they'd go with flechettes ... available as ... (3,700 nonexplosive penetrator rods... 350 14-in. rods, 1,000 7-in. rods, and 2,400 2-in. rods) standard load weight is 420 kg so, so 370 random "kinetic drill" targets require about 42 kg. That's a lot of energetically "free" drilling. My theory is, why waste the kinetic energy inherent in orbital bombardment? Instead of a rover-mounted drill, drop enough "thor rods" and you've got hundreds of kinetic drills within the landing ellipse. Then the rover only needs to brush the dust of recently broken rock fragments.

FYI, as of 2019, a "Hard Target Sensing Fuze" should be operable. It sounds promising; designed, not only survive a 15,000 PSI impact from punching through "X meters" of rock or reinforced concrete but actually measure density as it goes, in order to determine how many floors of the underground bunker it has passed through before triggering.

Yep, sounds like something a planetary geologist might want to tinker with.

So, for a kinetic strike probe, you'd need
-one tungsten "thor rod" with sensors and smart fuze at the back end,
- one solar powered data station deployed on a parachute, and
- one army surplus spool of 3,000 meters of TOW missile control wire connecting them for data gathering

ADMIN NOTE: Although this is indeed a very slow-paced mission compared to previous Mars efforts, let's please not diverge excessively into what-if design speculation. I'd also add that some members here are doubtless subject to the provisions of International Trafficking in Arms Regulations (ITAR) as part of their day jobs, so we really aren't going to encourage discussion on matters that may cross lines.

InSight is on Mars, where it is. Not gonna go anywhere else. That is the topic of this thread.

Ah, well,
is the seismometer active as it sits on the lander deck, or does it only wake up when deployed?

Curious because recent articles discuss the possibility of strong meteor showers at Earth this December;
(either Monocerids or Phoenicids).

That got me thinking, what meteor streams is Mars expected to encounter during the next several months?
Can it get usable data while the seismometer is stowed on the deck, only after deployed?

This article has great info on meteor streams at Mars and Venus.

https://academic.oup.com/mnras/article/402/...748682#25879660

I would not expect meteor showers to cause impacts on Mars. A typical altitude for meteors on Earth is 80 km and the pressure at that altitude is also attained far above the surface of Mars. Meteor shower impactors are normally quite small.

There will be macroscopic impactors hitting Mars regularly, but not necessarily correlated with meteor showers.

It might be interesting to see if impacts are noticeably more common when the high altitude regions on Mars (e.g., Tharsis) are oriented in the direction of Mars' orbital motion.

We have new images from the SEIS instrument tweeted by the president of CNES: https://twitter.com/JY_LeGall/status/1070561717367779328

Yes...but those images are not yet on the raw image page. What’s wrong here ?

Probably a fault on the public server... Hopefully they'll fix it soon