[X] My Assistant

[Steve G]

Tricky to line up the two RAC images but here is my attempt.

[climber]

It seams to me that the part further than the actual sample and before the distinctive mark of the arm colapsed a little bit I guess under the pressure of the arm. I have the feeling that the consitency of the soil is like talcum powder (Yeti) even if we can see these little clods.

[stevelu]

Yes, even finer than talc probably. I believe that the dust on Mars is much finer than any that is stable in Earth's environment -- probably because of the moisture in our air. But still substantive enough that the Martian winds can clean the rover's solar panels of it, and can whip it up into storms that homogenize it, to some degree at least, planetwide.

But I'm an amateur. Anybody want to tell me if I got that right? Is Ann Clayborne in the house?

[nprev]

Well, speaking as an amateur myself, I've always wondered about the electrostatic properties of Martian dust. Are the clods sticking together because of this?

[slinted]

Here's my try at RAC color. Since they are starting each sequence with an unlit image followed by the R, G, and B lit images, I tried subtracting each lit image from the unlit image, isolating just the contribution of each light. The results are vaguely un-awful, even working from the raw jpegs (although I did blur them significantly to reduce the compression artifacts). I look forward to seeing what can be done with the calibrated data!



update: Changed the method a bit, and updated the image. Now I'm using the color information from the subtraction images and the luminance information from the "no light" image for a sharper look. Anything not lit by the LEDs comes out psychedelic

[silylene]

Higher resolution version. Interesting pattern lower right on the rear wall of the first dig.
[attachment=14524:SS007EFF...FEL1M13d.jpg]

Also interestingly, it looks like to me from the 3D image in the undisturbed soil that there are possibly many tiny blackish 'weep holes' scattered about in the surface soil crust. Perhaps these possible weep holes are formed by outgassing of subliming water and CO2 ices?

[Bill Harris]

Yes, even finer than talc probably. I believe that the dust on Mars is much finer than any that is stable in Earth's environment -- probably because of the moisture in our air.
<snip>

Remember the depositional environment here. The fine dust is an aeolian deposit, and very fine material likely in the micron-range, with some volcanic ash. The coarser material are likely re-worked regolith and fractured rock from nearby impact ejecta (eg, Heimdal). Some rocks may be made of water ice with sediment and gases (possibly even in a clathrate). The ice we see is likely from repeated deposition of hoar-frost, which may end up being preserved when an insulating blanket of regolith/dust is emplaced. I'd suspect many discontinuous layers ranging from ice-rich/soil poor to ice-poor/soil-rich.

Has anyone worked out a particle-size distribution of the aeolian sediments of the dust based on Stokes Law?

A very alien environment.

--Bill

[ugordan]

Great stuff. If I understand correctly the impact of a uniform bias (such as solar "white" illumination leaking into the scoop here) on the result of CIE XYZ calculations, they should in principle only desaturate the color of a sample illuminated with RGB diodes, but not completely in shadow. Of course, the luminance of each diode most likely complicates this a lot since for calibration you'd have to scale each filter by their relative brightnesses and then you end up messing with solar whitepoint bias as well. Long story short, we need to look at samples during nighttime

Here's my take on the color assuming the scoop interior is sufficiently in darkness and the scoop itself is more or less gray. 2 observations were done at two distances, I've merged two of the same. The upper shot seems to be in better focus.

[climber]

The upper shot seems to be in better focus.

It also show a ochre/gold color barely visible on the other picture.
I'm not a specialist (nevertheless I'm in the agriculture buisness) but it's the more Earthlike soil I've ever seen on Mars.
We've gona need a scoop or arm emoticon I guess

[ugordan]

It also show a ochre/gold color barely visible on the other picture.

Be very wary when interpreting the color in these raw composites! This is just representative stuff. About the only safe conclusion we can make is that the soil color is different that the scoop color.

EDIT: Here's a different processing, this time also with subtracting the monochromatic signal and filtered to remove noise:


I'm inclined to think the above is a more accurate version than my first try. Definitely looks more Martian. The purple bit is due to low S/N of raw files.

[centsworth_II]

I gather that in the images taken so far with the RBG LEDs, solar light is a complication. I wonder how taking such images at "night" would work.

[jamescanvin]

Quite well I would expect, the images of the scoop taken during cruse when it was very dark inside were good.
However, calibration shouldn't be too difficult given the data the team has, I doubt we'll see them resort to night time shots.

Of course you'd have to wait a good while yet for any night to arrive!

[climber]

Be very wary when interpreting the color in these raw composites! This is just representative stuff. About the only safe conclusion we can make is that the soil color is different that the scoop color.

OK, I maintain it's Earthlike...at least Roland Garros like

[jamescanvin]

Official colour version of the first scoopful.

http://fawkes3.lpl.arizona.edu/images/gallery/lg_1698.jpg

[ugordan]

Official colour version of the first scoopful.

Hey, if you kick the saturation up of my second try here by 40 Photoshop units, turns out it doesn't look that much different!

Great release. Looks like they glued in the overexposed edge of the scoop to the right, though.

I was wondering if that whitish stuff was a sun reflection, but it didn't move as I'd expect. Looks like it's definitely scraped off bits of something white.

[climber]

Looks like it's definitely scraped off bits of something white.

and Roland Garros like color too