On the Road Again - volume 6 - Page 20

For direct to Earth (DTE) communications, the rover has to turn so that the high-gain antenna points towards Earth. A DTE session might have been necessary because of the Odyssey safe mode (now fixed).

The backwards autonomous navigation (tested in the last drive) also involves partially turning the rover to compensate for the fact that the direct backwards view of the navcam is blocked by the high-gain antenna.

Another rock with an unusual "sunshade"-like form. In previous examples, the "sunshade" shapes were planar and were attributed to differential erosion by the geologists. This "draped-over" shape may be more difficult to explain.

The same image in ||-eyed form instead of X-eyed. Personally, I find the parallel-eyed subjective image is larger and easier to see than the cross-eyed one. (I can now see it both ways.) Of course, with ||-eye viewing, the images should be no further apart than the distance between the eyes.

Ah, the "two-step" is part of the sol 2311 auto-navigation backwards drive.

Here is the sol 2311 180 degree pan looking back and here is the 180 deg pan looking forward.

A peculiar rock from sol 2309:

and gravel piles from sol 2301:

Any ideas how old these gravel piles are - and how they came to be where they are?

The "stain" is mostly covered by dust now. However, the tip part that is not covered, when viewed in stereo, looks like it is not completely flat, i.e., it appears to have some material that sticks up slightly from the rover deck.

an unusual sol 2299 ( Jul 13, 2010 ) 3D image:

see Flickr comments for a discussion of the odd features in this image.

Barsoomer, I'm not convinced that the "stain" has any height.

Look closely at this sol 2313 ( Jul 27, 2010 ) backlit view:

I don't see any shadow behind the "stain".

In fact, the dark "stain" has become a "bright" area, so I'm guessing now that the "stain" is a clean dust free area of the deck.

Horton, the part that has height is beyond the region shown in your image. It is the part that was formerly the "tip" of the stain, and is only visible in images that show a wider area around the sundial.

I have made a crude 3-D image (shown above) from navcam frames that inmdicates the dark raised area. Perhaps you can do a better job.

In the turned-over soil here, there appear to be berries-on-stems similar to what we saw in some rocks at Concepcion. If these are wind tails, they must have developed in the few hours since Oppy disturbed the soil.

Wonder if there was an associated cleaning event.

sol 2296-2299 ( JUl 10-13, 2010 ) animation of formation of berry wind tails:

This 2X animation is well worth the time to study! Yes, "wind tails" can be created ( and distroyed! ) in a matter of seconds with the right wind and soil conditions. My guess is that all the wind tails we see in the Meridiani "bedrock" are quite recent.

Perhaps the "bedrock" is more like hardpan than rock. That would explain a lot.

Horton, that animation is wonderful. Clearly, a large amount of dust was moved and dumped on this area during the recent "cleaning event."

However, I am not entirely convinced that these are all "wind tails," or at least something a little strange seems to be happening. Consider the crop of berries in this excerpt from the scene:

In your animation, the area where this crop appears in the second (sol 2299) frame is a hole or empty area seemingly devoid of berries in the prior (sol 2296) frame. Where were those berries in the earlier scene? I might guess that the large mass of dust deposited caused berries just above the hole to "lean" down. But that might suggest that the berries were on pre-existing flexible (!) stems. The only other explanations I can think of are the berries rolled down a little after the dust was deposited, or the berries were blown onto the hole area, or the hole area was eroded until deeper berries were exposed, but none of these seem satisfactory to me. What do you think?

Anyone know the watt hours before and after?

> Anyone know the watt hours before and after?

You can find the answer here:

[link] #recient (sic)

In brief, the watt hours went from about 360 on Sol 2294 to about 490 on Sol 2300. That was one humongous cleaning event! It's now well over 500.

After studying Horton's #390 some more, it seems that a large amount of material was eroded from the bottom of the soil pile, since its bottom margin appears to have receded. In that case, it is plausible that the appearance of the additional berries has resulted from erosion of the clods and exposure of deeper material. So, yes, it does seem likely that those are "wind tails."

It is remarable that a wind gust could cause such a degree of alteration. Maybe the dust devil passed over this spot?

Horton, Wow, Great animation in reply 390. What changes have taken place over those 3 sols is far from simple to see and I'd find it a lot harder without your efforts.

There must have been some erosion of the freshly disturbed soil because most of the tailed berries are not visibly protruding in the first image. On the other hand I see at least one protruding berry in the first image that GAINS a tail of material where there was no material before. Overall, deposition seems to be the main change, but the sharp edges on all the clods also seem to have relaxed or eroded. From the way the fines seem to be pasted on to surfaces it looks to me like dust has been deposited as opposed to sand. I wonder how much of the new mantel is from far away and how much is material made available for re-arrangement by the disturbance?

This is a fast Martian aeolian process consistent with my theory that dust is the big actor.

sol 2315 ( Jul 29, 2010 ) L0 3x1 in drive direction:

The drive was a short 11 meter backwards drive - after turning 180 degrees???

500+ watt-hours of power and not moving every day???

Not a clue.

Looks like a few clouds in the sky:

Unusual rock with light-colored middle, but dark base and dark topping. Resembles an ice-cream dessert.

Barsoomer, thanks for the link. The cleaning event occurred on my birthday, a nice present!

"What a muddy mess!" Note the stiffness of the raised imprints of the rover wheels. This not the consistency of talcum powder or sand; it looks more like squeezed slightly damp soil.

Further about Horton's animation in 390 and my 395, I'm thinking that the disturbance caused by the rover wheels is the key reason why such dramatic change can take place in 3 sols. All the rest of the landscape has evolved toward a state of slow change.

I think that almost all the material involved in the changes comes from the disturbed area not from afar. Look again at the animation. There is a dramatic difference between the big changes on the near side of the debris pile and the far side where there is almost no change. Both the disturbed far side of the pile and the undisturbed surface beyond that show no change. The wind tail orientation is consistent with the far side of the pile being protected from wind. To metamorphose in the way we see apparently both disturbance and exposure to wind is required. What mode of aeolian movement is implied? I'm mystified. Direct wind erosion of dust from the surface of crumbling clods? Tumbling dust-bunnies moving dust over only short distances? How much of the whole process depends on wind and how much on the collapse of weak temporary clods? The dramatic difference between the two sides of the pile suggests that wind has been really important. The final uniform, slightly "grainy" texture of much of the smoothed areas is interesting. There's a lot to study here.