A short drive on sol 180. Looks like we have arrived at the candidate coring site dubbed 'Citadelle' LINK
4-tile Navcam mosaic, looking at the tracks. Roughly assembled in MS-ICE with some minor de-greening
Click to view attachment

Thanks for the heads up. The archive includes the first browse images of the RIMFAX ground penetrating radar:

https://pds-geosciences.wustl.edu/m2020/urn...radargram/2021/

The metadata include the start and end locations of the profiles. The vertical axis is in the time domain but I could not figure out the scaling. It looks very vertically exaggerated. The documentation explains that the images were vertically shifted to account for topography but does not say how. I think that means a horizontal line does not mean exactly constant time. There is much more documentation so there may be a chance to find out more about the vertical scaling, and then also if there is an idea on how to relate to depth.

sols with radargrams (= interesting, longer profiles):

47
48
49
52
65
66
72
73
84

Sol 180 - the circular view shows how the rover moved to get to its target, especially when compared with the last one.

Phil

Click to view attachment

The documentation refers to Hamran et al., 2020 as the main RIMFAX publication which cites Stillman and Olhoeft (2008) and Cunje et al. (2018) as sources for regolith properties. The relative, dieletric permittivity (real, e'r) is directly related to the electromagnetic wave speed needed to relate travel time to depth.

The first source arrives at values between ca 2.4 and 3.5 for 5 analogue materials at a density of 1.6 g/ccm .

The second source gives values around 3.5 for clay-mineral bearing analogues at very dry and cold (Martian) conditions.

In addition, Hamran et al. give values of ca. 7 for dense basalt and 2.8 for basaltic regolith.

The radar wave speed v is c/sqrt(e'r), and the depth d of a reflector is d = v t/2 where t is the two-way travel time (probably plotted on the radargrams).

d(0.4) = 299792458 m/s / sqrt(4) * 0.4 microseconds / 2 = 30 m

So the vertical scale of the radargrams should be on this order of microseconds. Let's see if there is any hint of that kind of scale. There are 2048 pixels, eg. ca 0.2 nanoseconds per pixel.

Forum moderators: Please consider if this and other PDS related posts above would better fit the new 'Data in the PDS and the Analyst's Notebook' topic. If so, please do not hesitate to move posts. I think I will continue any discussion in the new forum.


The calibrated data documentation has helpful information.

There should be an annotated version of the browse images which does not appear to be available yet.

The uppermost, almost transparent portion is air from the antenna (at 74cm) to the ground level and should correspond to about 5 ns.

There are 3 modes: a surface, shallow and deep mode. The released calibrated data csv has data for all three modes but apparently the browse image shows only the shallow mode data.

The csv data has many fields/columns including max time depth which is the two way time of the last sample. It is 290.476 ns for shallow mode (half for surface, and double for deep mode), at least for sol 47.

0.4 microseconds may have been a pretty good guess then. So it appears that the radargrams show perhaps 30-35m depth (although there is no signal at the lower half in general).

The actual data have 16384 depth samples per sounding, the browse image only shows 2048 pixels. So it may be worth converting the cdr csv data into images.

A couple of 3D models of the Sol-180 workspace.

MastcamZ
https://sketchfab.com/3d-models/mastcamz-ar...8558560ab31aae3

Front Hazcam
https://sketchfab.com/3d-models/perseveranc...b8529fd730df42f

Mission update (blog) from Roger Wiens dated August 23, 2021
Stratigraphic Layers!
Phil may be able to identify a couple of past targets from this mission update for his maps
LINK
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Sol 180 anaglyph:
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A bit surprised of the approximations of naming regarding the French names. I can find a Mûres village or another one called La Mure. In the later, forgetting the « La » is like forgetting the « Los » in Los Angeles.

Two targets names for sol 281 at the Citadelle

'Grandes Tours du Lac'

'Manior'

Click to view attachment

Source

Phil Stooke (and others)
More target names Not exactly a flood, but it's a whole lot better than the drought we had before
Click to view attachment
Source

Drool! But be careful... typically a rover does morning science and an afternoon drive on a driving sol - so as an example Cheval Blanc illustrated at the sol 131 location should be at the sol 130 location (it's visible in my sol 130 circular pan). It was investigated on sol 131 before the drive. This is the only one I checked so far, but it's probably not alone.

(EDIT: now confirmed, it's also true for the sols 127 and 130 names, all belong to the location of the previous sol.)

Phil

"A bit surprised of the approximations of naming regarding the French names."

Don't forget it's only a blog, probably done under very tight time pressure. The more official names may look different in the PDS when we get them in 6 months time.

Phil

JPL Ingenuity image update

The photos from Ingenuity's flight 12 show that at South Seítah, contrary to expectations, sedimentary layering is not obvious. As such, the mission scientists are evaluating whether it's really worth it to trek there or whether to keep explore the Artuby Ridge instead.

Proving the worth of a UAS.

--Bill

Perseverance Team Selects a New Rock to Abrade
Nicknamed "Rochette," at the center of this image
LINK-1 LINK-2
Click to view attachment

Rochette, a loose rock on the surface apparently related to an en-situ outcrop behind it? This is not a MER-style RAT, but a percussion-based coring bit. I'd fret about the rock torqueing around as it was cored.

--Bill

Rochette is the same rock labelled Manior in the illustration of named features posted by Paul earlier. Manior (is it perhaps supposed to be Manoir?) may just be a specific point on the rock, targeted by LIBS or something else.

The initial abrasion for pre-sampling science, or a pre-load test, will probably confirm or refute its stability.

Phil

The abraded target nicknamed 'Rochette' on sol 185
I have rotated the image 180 degree for easier viewing, raw colours but cropped the dark edges
Click to view attachment

What an interesting set of textures, especially the "crust" on the top. And a weathered apparently clastic sequence below.

--Bill

Made this comparison comparing the two abrasions so far. It seems the new site's rock is 'better sorted' and 'finer grained' on average than the previous drill site, to use sedimentary terminology (but this may very well be an igneous rock). The new site also lacks the large voids that the previous one had which may indicate this rock is less weathered, which would increase the chance of sample aquisition success. No colour/contrast processing, just raw images.

I based the scale off the belief that the diameter of the abraded section is 27mm, the same as that of the drill bit holes, but I'm not sure if that's correct.


Click to view attachment

Below is the info you need.... It's an extract from this pdf:-
"The Sampling and Caching Subsystem (SCS) for the Scientific Exploration of Jezero Crater by the Mars 2020 Perseverance Rover" (Moeller et all) LINK (Paywalled)

There is a Hazcam image for context of the location of the abrasion on Rochette, and a Watson closeup which I rotated, cropped to avoid the shadows, and stretched a bit.

Click to view attachmentClick to view attachment

Originals and attribution:
https://mars.nasa.gov/mars2020/multimedia/r...AZ02008_02_0LLJ
https://mars.nasa.gov/mars2020/multimedia/r...LC00720_000085J

The abraded surface shows dark, perhaps greenish, grains, quite a bit of bright alteration, and oxidized, stained areas. The abrasion successfully avoided any of the cavities which can be seen on other surface areas of the rock. There is also a wind polished, striated, very thin weathering crust which appears to be responsible for the shiny appearance of the rock. There seems to be none of the blackish matrix which could be seen on the first target, Guillaume.

Thanks for this, I've now updated the graphic to have the correct scale.

With that I can measure that the abundant dark grey components in the close-up of Rochette tend to have a diameter of roughly 0.25mm, so if this is a sedimentary rock the average grain size would be on the boundary between fine and medium sand.

Click to view attachment

Rochette appears to have broken off from the mainly buried rock immediately behind it. This gives an indication of the internal structure of Rochette and there does not seem to be any evidence of laminations.

The surface of Rochette seems intetesting. Hopefully they'll core a sample to include that crust, instead of doing it from the "RATted" surface.

--Bill

What was said earlier was that at each sampling site they will do a detailed pre-sampling analysis and then collect the sample nearby.

Phil

Sol 184 LMastcam-Z:
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Another LMastcam-Z view on sol 184:
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Sol 187 Mastcam-Z left eye images of "Rochette"
A) Raw image with filter 0 (RGB)
B) Multispectral filters 0 to 6 principal components transformed to false color RGB
Colors in the legend are averaged from the image
1) Rock ventifact surface in direct sunlight. The color differs from the abraded interior.
2) Crust (desert varnish?) or hard coating on ventifact surface, partially eroded or spalled
3) Dust accumulation
4) Abrasion powder
Click to view attachment A Click to view attachment B

Any way to look for manganese or zinc?

What would Manganese or Zinc compounds suggest?

I'm wondering if this dark zone might not be contact metamorphism from the contact of the underlying clastic unit with molten Basalt.
This will be an interesting specimen.

--Bill

Manganese and zink are excellent polymerization/cracking catalysts and so are very interesting for a-biotic or pre-biotic organic chemistry. Industrial "cracking catalysts" use manganese silicates and zink ferrites are to break (or make) long chain hydrocarbons.

Similar grains might help turn atmospheric methane into sticky paint like goop that sticks to rocks and makes "desert varnish".
Interestingly, THAT sticky goop traps MORE minerals in dust and you get more potential catalytic compounds. Think of the catalytic converter in a car, it makes it much easier to convert hot long chain hydrocarbons into CO2 and H2O. That works in reverse, so a catalytic layer of "desert varnish" would change the energy budget for creating Martian methane or organic chemicals.

So, if you wanted a sample of EVERY mineral in the central & eastern USA, but could only take 1 sample, where would you go? The answer is- the Mississippi delta- because the delta sequesters microscopic mineral grains from every different type of Earth rock in the Mississippi watershed, carried their by water currents. But, that ALSO means you have tens of thousands of mineral grain catalysts close to each other, and subject to flow from fresh water rivers and tides.
So, the Mississippi delta, and Jezro delta, are perfect places to study the catalytic properties of microscopic mineral grains.

https://www.sciencedirect.com/science/artic...167268195000496

I fall in behind Andreas' " a wind polished, striated, very thin weathering crust". "Rochette" appears to be the product of erosion under current environmental conditions and given the basaltic provenance my stab in the dark would be primarily Fe oxide/hydroxide. Supercam should be able to determine the composition and we will be enlightened at what is going to be a extremely interesting LPSC 2022.

The Mississippi River watershed and delta is likely an overreach in comparison to the Jezero watershed. The Mississippi is huge in comparison and the time of travel of the suspended and bedload sediment can be measured in weeks and years. The sediments are quite weathered by the time they reach the Mississippi Delta. I don't recall it's area and I've not measured it, but I've the impression that the Jezero watershed is not that large. The later surface was the Syrtis volcanic province, which means basalts and basaltic clays and weathering products. I don't recall.what the pre-volcanic terrain was like, but I'd suspect more basalts and basaltic clays and weathering products.
It will be instructive to get.a better idea of the chemistry of the near-ubiquitous films and varnishes of Mars.

--Bill

Core in the sample tube (Sol 190)
I've roughly brightened the inside of the sample tube
Click to view attachment Click to view attachment

Rocky sample inside!

Good show. I see core in the core tube.

It looks as though they conservatively didn't include the varnish/ weathered top of that section.
ADDED: no, wait. The actual coring location was above the initial RATted cut; you can faintly see it below the core hole under the cuttings.

--Bill

Click to view attachment

Detailed press release LINK
I have annotated 2 of the photojournal images (for those not familiar with the coring bit etc)
Click to view attachment

Here is the Sol 182 partial panorama and seen also in 3D (reduced versions to fit in the Forum)...
Enjoy
Click to view attachment

(Cont.)
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...with a zoomed section (real size) on the background
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Sol 191 SuperCam RMI with Mastcam-Z context

Click to view attachment Click to view attachment

The sol 192 images are starting to hit the server, at this time there are 173 images, including several 'end-on' views of the sample tube, but using my basic processing skills I can not resolve if the core is there or not. Maybe one of the image wizards can stretch the images?
They did acquired full 12 tile Hazcam's, that I guess is just in case the errant core 'popped out' during the percussive cleaning of the drill bit.
I managed to roughly assemble the L-Hazcam tiles in MS-ICE.
I'm still working on the NavCam tiles.
Click to view attachment

Frames taken yesterday of the coring bit are arriving now. I averaged four of them and compared to the core seen on the coring bit on Sol 190.

There is a groove mark in the border of the core visible and some of the marks on the interior of the core are also visible.

Click to view attachment

Are the two images in your post both the new images or is the insert the just-post sample image (prior the the sample "disappearing?") and the stretched "grainy" image the averaged new images taken under the better lighting?

The background image is the averaged image with the better lightning conditions, taken yesterday. The insert is the image taken after the coring on Sol 190, that has been rotated to show approximately the same orientation.

Thank you for the clarification. My interpretation is that the sample plug is still in the tube. I think I can make out bright spots in the sample that sorta match between the two images.

Great work, and thank you for posting so quickly.

Sol 192 Mastcam-Z images of the left eye of the drilled "Rochette".
- Raw image with filter 0 (RGB)
- Multispectral filters 0 to 6 principal components transformed to false color RGB.
The average spectral reflectance of the rock interior (olive-colored drill cuttings) differs significantly from that of the rock surface (blue false color).

Click to view attachment Click to view attachment