The Stain - Page 2

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Posts: 3465

Reply: 21

PostPosted: December 4, 2010 9:00 AM 

er, dx, et al, you might want to check out the work I have already done on the stain before you do your own research.

Here are the Flickr images I have tagged so far with "sundial" and "stain" - including this animation which shows the first appearance of the "stain" on sol 1621 ( Aug 15, 2008 ) - just visible behind the sundial.

I first mentioned it on Feb 23, 2010 in reply 294 of On the Road Again - Volume 5, so you might want to read the comments from that point on in volume 5, 6 and 7 of the "On The Road Again" Topic.

Barsoomer has done a lot of work on the stain also, so you might want to pay attention to his posts.


Posts: 1661

Reply: 22

PostPosted: December 4, 2010 10:55 AM 


Thanks for the removals.

I also know that you did make considerable time induced research on the stain, but not to the extent of first notice. That I did not know. I thank you for the heads-up and will certainly review yours and Barsoomers posts.



Posts: 344

Reply: 23

PostPosted: December 5, 2010 1:58 AM 

Horton, I wonder if you could maybe do an updated version of


with a more recent navcam image? It would be wonderful in stereo with a rapid blink between the two images, if that was feasible.


Posts: 3465

Reply: 24

PostPosted: December 5, 2010 9:45 AM 

stain from sol 1919-2435:

The pancam images used in the animation have about 2.9x the resolution of the navcam images - but unfortunately the images were downsampled to 1/2 size - but still 1.47x more resolution than the navcam images.

The fact that the sundial calibration image crops have not been abjusted in width to include the extra 20 pixels or so necessary to monitor the stain is proof that there is absolutely no official interest or curiosity in the feature.

er, Barsoomer, as far as I know there are no full size all filter pancam images of the deck.

What additional information do you believe an undated version of the image in reply 23 would provide?


Posts: 344

Reply: 25

PostPosted: December 5, 2010 3:02 PM 

> ... there are no full size all filter pancam images of the deck.

Sol 13 was the only one I could find, which of course was before the stain appeared. I have been hoping the MER team would do at least one more to compare with Sol 13.

> What additional information do you believe an undated version of the image in reply 23 would provide?

I would like to get an idea of the 3-dimensional shape of the stain, with an image of the wiring on the clean deck as a calibration point. A stereo version of your blink animation (linked to in reply 23) might provide that. I think a more rapid blink would also help the mind to fuse the two images and see how they relate to each other.


Posts: 344

Reply: 26

PostPosted: December 5, 2010 3:29 PM 

The MER team seem to have a great interest in this part of the rover's anatomy. Nearly 40 images came down today.

Note the localized cleaning in the bottom right solar panel. While the stain has sharp boundaries---as sharp as a shadow---this one has a diffuse boundary, very different from the stain.


Posts: 3465

Reply: 27

PostPosted: December 5, 2010 7:17 PM 

Here is an animation of the L2 filter view of the Mini-TES calibration target from sol 2201-2435.

Here is a full color view of the target from sol 702. You may find more images of the calibration target by searching my Flickr images with search terms "calibration" and "target".

The most interesting "accidental" feature to me is the straight dark line in the bright dust to the left of the target.

What is interesting is that the line appeared in stages: The first 2/3 nearest the target appeared, then in the past few months the last 1/3 appeared in two more steps. Also notice there are several other existing lines in the dust parallel to the long line.

The parallel lines appear etched into the deck in the sol 702 images so perhaps dark dust is simply following the groves??? Or light dust is being swept out of the grooves???

Any observations that might resolve the puzzle?


Posts: 3465

Reply: 28

PostPosted: December 5, 2010 7:25 PM 

Barsoomer, I forgot to point out that the most likely explanation of the dump of Mini-TES calibration images today is that those images must have a very low priority now that the instrument is no longer operational and all other images with higher priority ( including several L1 panoramas ) have been downlinked.

I would guess that there are some very long drives planned with long autodrive sequences which will flood the memory with images - so the backlog of old images was cleared.


Posts: 3465

Reply: 29

PostPosted: December 5, 2010 7:47 PM 

Also also forgot to reply to the request for the updated animation:

A pancam pixel is 0.015625 degrees wide - which at 2 meters is about 0.5 mm ( never mind the blurring from a fixed focus lens ) - so any feature less than that size can't be resolved without playing the "super-resolution trick.

I think that backlit pancam images of the stain near sunset would be the best chance of seeing any height.

As long as there is no official interest in this puzzle there can not be any resolution.


Posts: 14

Reply: 30

PostPosted: December 5, 2010 8:23 PM 

Has anybody written to people at NASA and asked for some more pictures of the stain area?



Posts: 14

Reply: 31

PostPosted: December 7, 2010 7:20 PM 

I Just sent an email to W. Bruce Banerdt, from the rover team. I explained the stain and sent a link to Horton's time lapse animation. I asked him for his thoughts on what it could be.



Posts: 344

Reply: 32

PostPosted: December 7, 2010 7:59 PM 

In this x-eye stereo navcam image from sol 2442, it looks like the stain has a bulge that reaches as high as the raised wire, which must be a couple of millimeters above the deck. Not sure if this is "real" or not, but it looks this in other recent navcams also.


Posts: 14

Reply: 33

PostPosted: December 9, 2010 2:58 PM 

Here is the response I received from my email, with the original email. The only editing I did was to x out my last name.

Dear Mr. xxxxxx,

Thanks for your support, and congratulations on your sharp eyes! Not many
people spend enough time looking at our calibration images to pick up
something like this. I asked Jim Bell, the Pancam instrument lead, about
it and he had this to say:

"I think they are little "micro-cleaned" regions of the deck, probably
caused by little wind swirls or vortices created by the wind going around
the deck topography and obstacles. We've seen little splotches and streaks
in that region (and elsewhere on the deck) for hundreds and hundreds of
sols, in fact. The shapes come and go, sometimes sharp, sometimes fuzzy.
Their color is distinctly "deck like"--that is, slightly blueish, allowing
these little micro-cleaned regions to be distinguished from shadows (which
are slightly reddish). I would guess that the details of their morphology
are likely dependent on the strength and orientation of the last big wind
gust. Someone could probably do an interesting prevailing (strongest)
winds study based on the morphology and direction of various wind streaks
all over the decks over the course of the missions."


Bruce Banerdt


W. Bruce Banerdt Project Scientist, Mars Exploration Rovers

Mail Stop 264-422 Tel: +1-818-354-5413
Jet Propulsion Laboratory Fax: +1-818-393-5421
4800 Oak Grove Drive
Pasadena, CA 91109


-----Original Message-----
From: ""
Date: Tue, 7 Dec 2010 16:17:36 -0800
To: "W. Bruce Banerdt"
Subject: Science Website Feedback from (Subject: Mars

>SUBJECT: Mars Rovers
>Dear Mr. Banerdt,
>My name is Stan xxxxxx. I am a High School principal.
>I have followed the Mars Rover Missions from day one. I congratulate you
>on your teams extraordinary work.
>There are groups of lay people that have followed the rovers intensively
>since the Spirit launch. We support you, and cheer you on.
>There is something I would like to call to your attention that at least
>one of the groups has been talking about that you might not be aware of.
>There is a peculiar stain near the Opportunity sun dial that grows and
>contracts. Here is a link to a time lapse animation.
>I was wondering if you can share with us any thoughts on what this
>"stain" might be.
>Thank You
>Stan xxxxxx


Posts: 14

Reply: 34

PostPosted: December 9, 2010 3:10 PM 

Any compliment Mr. Banerdt paid to me, I pass on to Horton.



Posts: 3465

Reply: 35

PostPosted: December 9, 2010 4:04 PM 

Stan, thanks for posting Jim Bell's reply.

So, unofficially it's all just cleaned deck.

I don't think the "big guys" have looked very closely because they don't expect to see anything "interesting".

If they had looked at the animation carefully they would have seen:

Not only the deck but also a corner of a solar cell have darkened - and most curious - metallic bright solar cell contacts have darkened - not gotten brighter!

Let me SHOUT a critical observation that disproves the simple "clean deck" hypothesis:


I think a full filter pancam analysis of all areas of the "stain" - deck, solar cell, wires - using "Ratio Color by Horticolor" would be most informative.

Ah well, thanks again for trying Stan.

The results are what I expected.

I will continue to follow the development of the stain with whatever scraps of data that are accidentally provided by the "rock guys".


Posts: 344

Reply: 36

PostPosted: December 9, 2010 7:00 PM 

The following was a response from Steve Squyres:

"Yep, I've noticed this feature, but I honestly haven't heard a whole lot of discussion about it on the team. Many dark and bright markings on the deck have come and gone over the course of the mission on both rovers, and everything I'm aware of that we've seen in the past has been pretty readily attributable to deposition and removal of dust. So things like this tend not to get a lot of attention any more.

We actually do get good color coverage of this general area each time we take a 13-filter Pancam calibration sequence. It doesn't cover the entire dark region, but the part closest to the cal target is visible. The most recent one was on sol 2425, I believe... so images like that (and, particularly, their evolution over time) might be of value for amateurs who want to study this feature.

Regarding its overall characteristics, when I compare a fairly recent L2 filter image of it:

to an L2 image taken right after we landed:

I guess I'm not totally convinced that it's anything other than an area that has been largely swept clean of dust. It can be very hard to draw robust conclusions when you're looking at things that are right down at the resolution limit of the cameras. But you're certainly right that it's a strange-looking feature... both darker and more sharp-edged than most of the dust-removal areas we see. I have brought it to the attention of a couple of the Pancam guys, and we'll definitely keep an eye on it. "


Posts: 1661

Reply: 37

PostPosted: December 10, 2010 9:22 AM 

Barsoomer, Stan>>>

The thing that bothers me is, why that particular area on the deck. And if it really is a 'clearing or cleaning' of the deck, small residue dust pieces should remain as 'wind-blown' mounds of residue and not a clean cut swipe. Frankly the swipe is the same as the rhetoric conclusion given by some-just to 'brush you off'.[tic]

But in my mind, no one really knows what it is or what caused it to happen.

Its a done deal then! Its put to bed until the next image indicates change.



Posts: 692

Reply: 38

PostPosted: December 10, 2010 11:28 AM 

Steve said: "I have brought it to the attention of a couple of the Pancam guys, and we'll definitely keep an eye on it."

So this mean our work isn't wasted! Thanks for bringing this (our meanings) to attention to the "Big Guys" guys.

Kye Goodwin

Posts: 1166

Reply: 39

PostPosted: December 10, 2010 12:11 PM 

Wow, Thanks Stan. What you have done is something of a first around here. Barsoomer, Wow again and thanks for taking the initiative and getting a response from Steve Squyres.

What have we learned? Bruce Banerdt mentions the similarity of the stain's color to the deck color which is maybe a little new information. We have found out that the rover team has no trivial explanation of the stain that was formerly unknown to us, nothing like "that's just deteriorating adhesive leaking from under the base" or some such. They are working with the same hypotheses that have been proposed around here.

The dust-removal theory has always been a contender because it is simple, but even if that is essentially what is happening I would still consider the sharp edge to be a really interesting mystery. It would then imply that the dust is forming a cohesive layer that is present over most of the deck but entirely absent in the stain - like peeling paint. I'm pretty sceptical.

It's good to know that there may be more scientific attention paid.

Kye Goodwin

Posts: 1166

Reply: 40

PostPosted: December 10, 2010 12:50 PM 

Again discussing the dust-removal idea. The stain has been completely covered with dust more than once and then re-darkened, each time over a larger area. This implies that even under dust the area that has been dark before retains some quality that allows it to be re-cleaned more easily. Further, this quality of being easily-cleaned can spread to adjacent areas.

Intuitively somehow I don't think that the dust is being removed from the stain area. I'm guessing that the dust is being made transparent. The dark color is the deck showing through, but this doesn't make it any less "interesting".

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