The Stain - Page 11

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PostPosted: March 24, 2011 10:42 PM 

Not sure what they used to paint it black. Every article I can dredge up just says paint. I'm leaning towards powder coating or an epoxy. I imagine the paint blew away with the sand that blasted it.

Add the http:// to the following to see a pretty good photo of it in original dress.
www.lpi.usra.edu/meetings/lpsc2003/pdf/1980.pdf

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PostPosted: March 24, 2011 11:54 PM 

Also found this tid-bit in an article here : (http://)http://www.sciencedaily.com/releases/2003/12/031231083412.htm

"To save weight, six holes in the shape of home plate were cut out of the underside of the aluminum base."

Maybe the gnomen was anodized black?

Ben, there's a post lost, somewhere south of #194, where I point to some of Hortons images that seem to show a gap between the deck and the caltarg.

Then from (http://)marswatch.astro.cornell.edu/Bell_Pancam_JGR.pdf

"The target is ~135 mm from the cameras when they are pointed at it, and it is viewed by the cameras at a fixed emission angle of ~53.5 ± 2.5D from the axis normal to the solar panels." Does this mean the sundial is not mounted parallel to the deck?

Six home-plate shaped holes underneath the calibration target, and the silicone outer ring is flapping...

I also wonder if the base is CNC milled aluminum or sheet aluminum? If sheet, it may well be hollow, with cracks at the corners. Dust could get blown in through the top flap and sift its way out the rear corner.

Ben


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PostPosted: March 25, 2011 12:36 AM 

Very interesting; I didn't realize the plate was so small. That makes the stain much smaller than I had envisioned. Shocked

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PostPosted: March 25, 2011 10:35 AM 

And this : looks like folded thin sheet aluminum.

Interesting one can find documents covering the construction of most of the instruments on the rovers, some with enough detail one could build the device. But of the pancam calibration target, there is very little to be found.

The photos I have seen of people handling it, they seem to holding it very gingerly.

Barsoomer


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PostPosted: March 25, 2011 3:52 PM 

[link]

Bill Nye was involved with designing the MER sundials, so maybe the above gives a clue. The main requirement for MER is that it not be a shiny black. This material link would seem to be the most useful but I bet they used some kind of carbon black.

Barsoomer


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PostPosted: March 25, 2011 3:54 PM 

[link]

Bill Nye was involved with designing the MER sundials, so maybe the above gives a clue. The main requirement for MER is that it not be a shiny black.

link

The above "Super-back" material would seem to be the most useful but I bet they used some kind of carbon black.

hortonheardawho


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PostPosted: March 27, 2011 5:44 PM 

sol 1621 ( Aug 15, 2008 ) view looking back on the rover track in Victoria crater:

My best guess is the stain is soil that was tossed behind the sundial during the 1621 move. If you look carefully you will notice the wheel trenches dug in the sol 1619 move.

Unfortunately, no images near the sundial were taken on sol 1619.

Notice that all the mucking around on sol 1618 did not create the stain.

sol 1618 ( Aug 12, 2008 ) L257 false color pan of the wheel tracks:

with a link to the right eye panorama.

There are some suggestive darker soils in the sol 1618 image that might be related to the sundial stain soil.

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PostPosted: March 27, 2011 7:16 PM 

That is much darker soil than purgatory.

I'm pretty sure the rover wheels don't spin fast enough to sling dirt but, perhaps a disturbed rock could act as a catapult...

An example of what Opportunitys slow turnig wheels can do though : http://www.unmannedspaceflight.com/index.php?s=&showtopic=3314&view=findpost&p=71722, they churned up quite a dust trail at purgatory that was imaged by MRO.

Barsoomer


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PostPosted: March 28, 2011 4:57 PM 

Exploratorium has new images.

If the stain was once alive, it may be dead or dying now.

Ben


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PostPosted: March 28, 2011 5:55 PM 

barsoomer; Just have to say it.
Do you mean dead literally. Smile

Barsoomer


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PostPosted: March 29, 2011 11:39 AM 

Or maybe it has just moved again. It seems to have reached the end of the deck. Next stop, slithering off? I'm curious to see what the lumpy area will look like, if and when the stain moves off it.

Barsoomer


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PostPosted: March 31, 2011 1:11 AM 

The stain cover continues to thin out. The stain material may be flowing off the end of the deck.

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PostPosted: April 1, 2011 9:17 AM 

FWIW, all the R2 frames to 2547, 1 second interval slide show. Timestamps in the comment.

hortonheardawho


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PostPosted: April 8, 2011 8:40 AM 

sol 2560 ( Apr 7, 2011 ) change in the sundial stain:

Well.

The stain appears to be "growing" from behind the sundial -- for the third time!

I am mystified.

Has the dark soil been blown back and forth behind the sundial twice?

Or is there an "endless" supply of dark "soil" behind the sundial??

Or... what???

Barsoomer


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PostPosted: April 8, 2011 11:12 AM 

Wow! The stain never ceases to amaze. During the long boring journey to Endeavour, maybe the Mer project can find the time to document this phenomenon as best they can.

It seems unlikely there is a further reservoir of "soil" on the deck in the hidden area behind the sundial. The alternative, which has been suggested before, is that it is emerging from a narrow gap under the sundial platform, which is only bolted onto the deck.

This narrow gap between two plate-like surfaces may support some kind of capillary action that allows liquid water to exist under Martian conditions. Then either this film of water is eroding the underside of the platform and causing some kind of slurry to leak out, or some type of organism, possibly from Earth, is growing in the gap and trying to expand its territory. I think the slurry might explain better the cohesiveness of the stain.

Barsoomer


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PostPosted: April 8, 2011 11:19 AM 

Does this rear hazcam image show the underside of the platform in that cutout in the center?

hortonheardawho


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PostPosted: April 8, 2011 12:50 PM 

Yes, Barsoomer, the top of the rear hazcam shows the underside of the deck. Here is the first rear view just after Oppy came off the lander deck on sol 7 ( Jan 31, 2004 ):

I did an animation comparing this image with sol 2560 image and didn't see anything unexpected.

Barsoomer


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PostPosted: April 8, 2011 8:40 PM 

The latest emergence of the stain took place between these times:

Sol 2558 14:09:31
Sol 2560 14:28:25

Above is the navcam taken at the "before" time.

Barsoomer


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PostPosted: April 12, 2011 4:21 PM 

A belated navcam narrows the emergence to between

Sol 2559 13:26:55
Sol 2560 14:28:25

Barsoomer


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PostPosted: April 12, 2011 4:25 PM 

Above is the Sol 2559 navcam intended for #219.

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