It also doesn't look typical Meridiani to me. The latest set of pancams are under very different illumination than the first closeups. Notice how Marquette, as well as what are presumably fragments of the same original rock, is now showing some specular reflection (black arrows in attached image). Not the extensive reflection we had from the Fe-Ni meteorites, but not like regular Meridiani rock either.

On the other hand, something caught my eye that looks kind of like a blueberry (white arrow). Of course the resolution isn't quite good enough to be sure, so I too am really looking forward to MIs of MI!
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I noticed that the other day; there's a block of something at the base of MI that shows it pretty clearly...

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I keep thinking back to 'Granada', on the edge of Victoria, where we saw two very different types of rock in close proximity to each other... one type shot through with fractures and cracks, the other much denser-looking...

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If this rock does consist of local Meridiani base rock; i.e. what the "pavement" is made of, then it is not very old at all. As I recall the RATs on this stuff have gone in very easily. As such, in this wind and sand blown environment a vertically standing sharp edge like that would not last long before it was rounded down. So in that event we could indeed be looking at ejecta from Fresh Crater.

And that reminds me. Does anyone know if a hardness formula was ever developed (or even workable at all) for the RAT? Perhaps a ratio of the number of motor turns to current draw?

From what I can see on my latest 3D pic, there is rubble from here to the horizon...

http://twitpic.com/p07dk/full

And there's some very interesting new structure visible on the sky-facing side of the slab, if you anaglyphalise (is that a word? It shoudl be! ) today's pics...

http://twitpic.com/p08v2

Today's pics? Where are you seing today's pics? I can't see today's pics...
BTW and totally off topic...are you seated Stu?
Have you seen Alan Stern's latest status at FB?
"About to call a teacher and ask her to think about flying in space-- again."

Just got back from work and haven't seen them before, so they're "today's" for me

My attempt at the Marquette Island mosaic:



James

Oppy's tour of Marquette Island continues...

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I think MI is out of the IDD workvolume after this drive, just a bit, so I would expect another step towards the rock before attempting any sniffing/imaging.

Edited: ... assuming the plan is to "touch" the rock and not only to do a 360º survey.

They might be planning a 360 before the IDD campaign to ensure they're in the best spot for an extended IDD campaign to give the FR a chance to catch its breath.

Here's the navcam mosaic taken at the current site; that's sol 2061.
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In Tesheiner's latest mosaic, the visible side of Marquette does not now seem so different from the other side . . .

Considering how narrow the base appears to be; what are the odds of it tipping over and the bottom edge hitting the IDD if they try to RAT this thing?

I proposed toppling it in post 596 but there were no takers for the idea. I still think they should try provided there is a safe way to do it. If it falls you see freshly exposed surface; if it doesn't then at least you know it isn't about to fall accidentally.

So, which side will you choose? That's far too dangerous I'd say. If it starts to move and come back on the IDD or whatever part of OPPY would be chosen to push...we're dead.

Does anyone have a size/mass estimate? That might shed some light on the risk of accidentally tipping this thing over?

I was thinking of a wheel.

Which side to push? The one that isn't overhanging.

Hmmm... big cloud of dust going who knows where, pebbles being dislodged and flying around. Sounds like a bad idea to me...

Way too dangerous -- if it could be done.

I would think that Martian winds pressing on the entire face of the rock could rival the pushing force of Opportunity pressing on a square centimeter or so. And it hasn't tumbled yet. Not that I've done the math.

edit:
Pushing below the center of mass?

I can't think of many things more terrifying than Oppy trying to topple that thing!
I seriously doubt it would be possible anyway, it doesn't look that unstable to me.

Anyway, going back a coupe of weeks, I'm still catching up. Here is Trinidad Crater:



James

Beautiful feast of Pans of Sol 2059 (Mon Nov 9). Sorta took my breath away. Couldn't resist just doing a quick job on them. Hand stitched, few adjustments and colourized. I'm sure someone else will do them justice!! Will post the full res pic on Flikr - 1.8Mg and edit link in here a bit later when I have time.

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If I may,
Why wouldn't the rock just lean over to the side?

Most likely outcome of Opportunity pushing on rock: No movement of rock and possible damage to Opportunity.

How did we miss this? Better watch out for the Meridiani bears...
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Oh, no! The dreaded Martian Desert Seal!!!

It's no use H4, they just won't be persuaded.

I'm still hoping someone will answer briv's question about the size of Marquette. Would briefcase-sized be about right?

If a wealthy relative died and left you a million dollar cane covered with diamonds, would you ever, under any circumstances use it to tip over a rock? What if the cane was worth hundreds of millions of dollars?

Tonight's catchup - most of the R21 colour drive direction mosaics I missed while without internet (sols 2034 to 2054).

I'll just put one thumbnail in this post to save space, but follow the link and you'll see all ten.



James

After yestersol bump, the IDD is right in position to start another "science campaign".
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Looking to the arm's attitude I'm wondering if this is an attempt to smash the rock.

This is one rugged rascally rock...

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I sure wouldn't like to try and push it over...

I might, if I'd already been humping it around the desert for six years using it to scrape dirt off of rocks, and occasionally rolling it down a steep hill with no guarantee of getting it back up.

(Just kidding... please don't push the rock...)

OK. Not exactly an imposing monolith. More like the size of a chunky, medium large handbag.

It looks a little larger than the 26cm diameter wheel. Still a hazard to run into. If the wheel climbed up onto it, the rover could be hung up*. And putting any force on the rover's old arm with its gimpy joint would not be a good idea. (Are they still afraid to stow that thing?)

*edit: On the other hand, from wikipedia, the suspension system "allows the rover to go over obstacles... that are more than a wheel diameter". Hmmmm. Probably the best shot at tipping the rock would be if the wheel climbed up on it. Good idea?

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http://qt.exploratorium.edu/mars/opportuni...cam/2009-11-12/

A lot easier and a lot safer than attempting to turn over MI would be to turn over one of the smaller rubble pieces by driving over it. Presumably they are fragments of the same bigger rock and so are the same type of rock.

I'm not sure what we'd learn from that though. Is the idea that the surface not exposed to the wind would tell us something about weathering or maybe how long the rocks have sat here?

Well, we are *well* past warranty anyway, so why not to take some risk? Unless drivers decide to ram the rock at full speed, I don't see why it would be that dangerous to push it. Keep in mind that if the rock topples, it might be interesting to examine how soil beneath him differs from open plain. Maybe this give a clue how long the rock is there.

There's phyllosilicates between here and Endeavour; I'd rather see those. Unless Marquette is an example, of course.

The topling process might hit the rover. THe topling process may kick up so much dirt it obscures the solar arrays and the cameras, The topling process rips the IDD off. The topling process takes a solar array with it.

I'd keep a LOT of things in mind.

Ha, ha! Too much coffee?

I too don't like the idea of purposely pushing on that rock. But really, it's barely larger than rocks the rover was designed to roll over. Still, no reason to go out of our way looking for trouble.

Reasonable question ... my answer would start with, how far "past warranty" is an immaterial metric. Over 2000 sols are in the books and that doesn't hinge on any decision made now. Risk loses its sting not when the past is extensive, but when the future is short. What does matter is what can be achieved and how likely the achievement is. A reasonable, but not exhaustive metric would be to look at the high potential science return of an Endurance campaign times the probability of accomplishing that campaign if (1) Opportunity is driven in a discovery-responsive but cautious fashion, or (2) Opportunity is driven to maximize hypothetical upsides of current investigations without respect to the 'opportunity' cost of lost future investigations if we just say "what the heck, we're past warranty, let's take some risk". I would suggest, at a minimum you'd have to show that the potential value of your risk taking times probability of its success would exceed the probabilistic impact to the Endeavor journey and campaign.

So, my answer in this instance would be: you're looking at a low probability of achieving something of limited value while accepting some risks to science instrumentation, mobility, and vehicle, all of which jeopardize more likely and more valuable campaigns between here and Endeavor and at the crater. (My opinion, only, btw, not speaking for anyone.)

Sol 2063 L7/R1 pancam anaglyph of SW face of MI:
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That's a statement worth remembering, folks; spoken like a true systems engineer! Hell, that's actually a very good heuristic.

Completely agree that, in this case, the risk/reward ratio yields a very straightforward answer of "no".

Yes, I'm also really really looking forward to reaching them. Can't recall where the nearest deposit is - how far off it is kms/days? Perhaps you can briefly remind me!

The answer may be in this:

http://www.agu.org/pubs/crossref/2009/2009GL040734.shtml

Could someone with access to the full article give us some more details?

The phyllosilicates are in the rim of Endeavour, as the abstract says. Hydrated sulfates are "in the plains adjacent to Endeavour's rim", again as the abstract says. There is no map in the paper showing how far out the hydrated sulfates extend into the plains.

At any rate, it looks like they're going for the less weathered face of Marquette.

And I think faint layering can be seen in Stu's terrific image of this face, running diagonally from upper left to lower right . . .

No map, true, but there is a schematic cross-section suggesting that the hydrated sulfates are encountered somewhere in the middle of the route, maybe in the vicinity of the 'mini-Endurance' crater. But for clays, we have to get to the rim hills.

Phil

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Bound water from CRISM raw data for Endeavour crater.
However, this is raw data so probably a lot of corrections apply for IR brightness, etc.
If I try for the various types of phyllosilicates detected I get hardly anything, or at least what seems to me random noise, but once again that's only the raw data.

There is CRISM data for the area around Victoria, and for Endeavour crater, but I'm not aware of CRISM observations on the planes inbetween.

Would CRISM distinguish between clays and hydrated minerals like jarosite? And why so much on the crater floor? Hydrated subsurface layers that deep, or brought down from near the surface by the impact?

(not a geologist)

MI's of Marquette (just in) sure look like a crystalline basement rock with inhomogenuities and mineral-filled veins. The debris all about the site makes me want to put my money on it being part of a clump of secondary impact debris.

Here's a mosaic of MI's MIs.
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Original pictures: http://qt.exploratorium.edu/mars/opportuni...ger/2009-11-15/

I don't see any obvious signs of variations in structure..