Looks like they decided to do a test drive to see how the surface behaved under Opportunity's heavy wheels (and the reuslt look great!)

Wow - only 1755 local - so that's pretty early downlink.

I think they've just driven up to some of the dark pile for a weekend IDD workout.

Doug

It does seem to be pretty cohesive stuff. Hooray! (Just felt like saying 'Hooray' - mainly for the drive.)

judging from the shadows, this also seems to put Oppy into a favorable tilt towards the low winter sun
-> start the next driving week with fully charged batteries

Perhaps hoping to climb to the top ofthe mound to get horizon shot in the direction of Victoria.

If it's business as usual, they will probably spend the weekend doing some IDD work on the hillock from where they are now. You're right Nirgal, they probably have a nice (small) tilt toward the sun now, so this may be a good chance to charge the batteries before heading off toward Beagle. I hope they will also get in a little Pancam coverage of the Apron from here, including Victoria.

The work area on the hillock apparantly is named "Jesse Chisholm" - or maybe the whole hillock is named "Jesse Chisholm," hard to say.



Or maybe Jesse Chisholm is buried under the hillock. That would be something.

Look alive, mateys.

There are images being posted at Exploratorium from atop the "Hillock": Pancams, Navcams and F/R Hazcams.

The Pancams are of the surface at the wheels, and look _exactly_ as I'd imagine that ejecta would look like: a mixture of pulverized basalt and evaporite. The wheel-track suggests a zone of sulfate salts just below the surface.

"Hillock" surface

wheel scuff

--Bill

I was only speaking of correlation of rock features. That disruption of the ripple is clearly related to the fracture. We've seen several very similar features since leaving Endurance. I suspect subsidence of the fill material within the fracture is the cause of these and the host of apparently related features.

On a completely different note, the dark cobbles in the sol 885 pancams down so far appear extremely fine-grained. I'm tempted to describe them as glassy, especially that larger, conchoidally fractured piece.

Sol 885, yes, todays. My first impression is "shocked", but glassy/conchoidal works. Would there be enough energy in this impact to cause impact melting? Victoria is a large crater, but in the scheme of things she's barely a bump...

--Bill

Not a great stitch - but this is the Jesse area - probably the IDD playground for the w'end.

Doug

Pretty nice! Beats my version.

Oh my.

The first look at the Sol 885 Pancams fit my mental image of what the VC ejecta should look like: poorly sorted, angular to subangular to subrounded basalt and evaporite. But these first color images from Doug and mhoward are distressing. At this resolution, it looks to me that there are a lot of small Blueberries distributed across the surface. I can see Blueberries in the weathered evaporite sand on the plains. I can't see them in the ejecta in great numbers.

I may be wrong; I see that the IDD is out with it's handlens in place so we'll get a proper look soon. But they do look berry-like at this time.

--Bill

This image is very nice. I don't much like what it's showing me. Is this the surface of the dark mound? Right under the surface is the soft powder. If this is what the eject blanket is like, we acould be in for a slow trip to the edge of Victoria.

I don't see anything that I'd clearly call blueberries. I'm seeing a lot of basalt, and what appears to be shattered obsidian, and perhaps some evaporite pebbles as well. This is lots more interesting than I was expecting... I was expecting basalt sand (the stuff the evaporite grew in). Clearly the sand overlays this more interesting stuff.

...Although it wouldn't surprise me to see blueberries scattered on the surface, considering the newer nearby craters which would have done a fair amount of splashing.

I hope that I'm reading more into these initial images than there is. I saw "blue" "rounded" and "quack". We'll have MIs soon.

I'm thinking that the reddish powdery material is weathered evaporite/sulfate. These fragments we see on the surface ought to extend through the ejecta (ie, homogeneous).

--Bill

Somewhat OT, but this guy died after eating rancid bear meat? I would hope that I would not make the same mistake. His other, more noteable accomplishments certainly deserve a place in history, as they already are.

There are berries here, though not as abundantly in this debris as elsewhere.

Autostitched Sol 885 Navcam pan:



Tracking database confirms MI campaign tosol.

Why would this isolated mound be representative of the apron?

Brian

My guess is via some sort of splash process. Picture initial impact, which throws up apron material (which presumably has the consistency of a pyroclastic flow, as discussed elswhere) which hits the ground, and parts of it "splash" and are thrown further... leaving the occasional isolated hillock. Alternately it could have been hurled directly here by the main impact. A nice 3D overhead view might clarify this a bit... see whether it shows evidence of horizontal smearing radial of Victoria.

While waiting a more informed reply... from previous posts it seems the general feeling is that the mound could have once been part of the apron but erosion has removed apron material and the mound is a remnant of apron which has not yet been eroded away.

In fact, I wonder if Victoria's apron may have once been much larger and even the patches of dark cobble that Opportinity has passed on its way were once part of the apron and remain after the smaller stuff has been removed.

When you least expect it -- Mars delivers.

I tell ya it's nice to be someplace interesting again -- I think I might have been getting a little woozy from all the endless rolling dunes.

Back from watching the flight of Space Shuttle Discovery.( STS-121 )

Here is the 360 degree panoramic view from Sol 883 and Sol 884.

Taken with the L navcam.

jvandriel

Very nice, jvandriel - and here's a polar version of it.

Phil

Click to view attachment

As anyone who's stitched MI's will testify - ones where there's a lot of depth ( i.e. a little cobble sat on the surface ) and near impossible to stitch...but I had a go. Not found it on the PC imagery yet, need the FH stuff to come down later.

Doug

Here is the view in the drive direction on Sol 884.

Taken with the L2 pancam.

jvandriel

Well now there's a challenge when I have a few minutes, I think I have an idea on how to make it a perfect match -- possibly later this afternoon as it's too hot here today for yard work.

In the meantime maybe that's a question you might ask Jim Bell next time. If they have any MI panorama test images, especially over a grid that would sure help.

and here is my first color version of Beagle Crater:



(I used a new color palette (derived from calibrated pancam data but also a bit "artistically spiced" color palette for this one ... so the usual color warning of course applies

Excellent work Nirgal... a real sense of being at Beagle from that one.

EGD... without having the tools to try it out, are you thinking of two MI stitchings, one matching near and one far, then overlaying the relevant portion of the "near" image back on top of the "far"?

That merging business... is that the same thing they are doing here?

http://anserver1.eprsl.wustl.edu/anteam/merb/merb.htm

Phil

Exactly as I was worried about, if you recall my posts a week ago. I am afraid we will find that the apron consists of shallow dark dunes on top of a dark substrate, all soft. I am concerned that the apron surface will be too soft to get to Victoria.

We've all seen what deep marks are left when the rover hits a soft dune at the wrong angle. the scuff mark on the mound looks nothing like that. It looks more like a mark left on a hard, compact surface. I think that if the apron is like the mound, Opportunity will be able to race across it at will.

I agree -- this surface looks an awful lot like the plains outside of Eagle and Endurance. If that holds true onto the actual apron, we're home free.

-the other Doug

If we go by the Satelite photos, the apron looks just like the terrain (Marain?) surrounding Endurance. Back then, we didn't even worry about getting stuck.

My guess is that such a mound could be simply created from a disintegrated, solid chunk of ejecta thrown clear of the ejecta blanket, rather than from a splash remnant. There is no evidence of the blanket extending much further. The Victoria impactor was a rock, not a mountain. I think... This thing is right on the bleeding edge, though, isn't it?
Such a large apron seems unlikely to me, but that is a good question. It is simpler to imagine that impact chunks were tossed randomly about.

Very nice picture Nirgal. The colors are very good

Let's me show an analgyphic of the panorama in the drive direction :

Terrific anaglyph Nirgal, you're on a roll man! Very nice views..

Nico

My initial thoughts were that this hillock is a splash remnant of the main ejecta blanket and shoud be composed primarily of pulverized basalt. There are an appreciable number of Blueberries at this Jesse site. More than I expected, but a reasonable number considering that apparent evaporite fragments are visible on the surface. Some BBs may be left over from the original pulverized mix and some may have been left behind as the Meridiani ripples moved through (ripples are visible on the ejecta apron to the south of this site).

My first impression of the Blueberries when we first saw them two years ago was that they were lapilli. They turned out to be hematite concretions. But, thinking somewhat outside of the box (and hopefully not out of the mainstream) , I wonder if some of these "blueberries" we see on the surface of Jesse are not lapilli? Looking at the MIs the surface of many of these "berries" are subrounded and not spherical. The surface of at least one of the cobbles in the current MIs has a crust or apparent "splash deposit" on it. I wonder if there was enough energy from the VC impact to melt some of the rock to form lapilli? I seem to recall that they found "iron spherules" at Barringer Crater in Arizona, so it may be possible.

The fly in the ointment here is that the last MIs of the last ripple before moving onto this hollock showed subrounded and subangular Blueberries, too.

Attached is an image of Hawaiian lapilli (I forgot the jot down the URL). Weather it a bit, blow away the dust and it looks Martian...


--Bill

I agree with your take on the ejecta blanket that we see today. When Victoria crater was formed, this area
would have been strewn with blocks of basalt and evaporite. Eons of weathering and thermal cycling have reduced it to the gravel looking mix that we see today. What remains is the harder basalt and blueberries with most of the softer evaporite blown away. Driving up on the apron should be a piece of cake.

Accretionary Lapilli

colorized MI pan of "west hillock":



Not very useful color for the large rock, it may be informative about the relative color of the smaller ones.

This is synthesized L2 / L7 ( infrared / ultraviolet ) so there is no pretense it is accurate -- but it is suggestive.

To my simple mind lapilli on a planet with the largest known volcanos in the solar system make a lot of sense.

A view across the apron taken on Sol 887: 1P206925979EFF74N8P2555L2M1.JPG



The 3D version is... interesting.

Yes, I confirm, it's interesting

Click to view attachment

We con see very softly the differents rim (near and far rim) of Victoria.

Here is an anaglyph of Sandsheet. I have flattened the horizon and increased the brightness to make features on the dark surface more visible.

Er... could you elaborate on what you find interesting?

It looks like we've got pretty significant dunes out into the apron 70 metres or so (using AlgorimancerPG). After that it looks quite smooth, though it's a bit hard to tell for sure since we're looking somewhat orthogonal to the dunes.

As far as the VC features, it appears we're just seeing the nearest part of the rim. I see no evidence yet that we can see over the near rim across to the far rim as well.

Specifically what I find interesting is that there appears to be a big dropoff in the near field, and it looks like a bumpy ride after that for awhile. However it's hard for me to tell if it's really that bad or if it's just exaggerated by the Pancam anaglyph. But it sure doesn't look smooth and featureless, at least not nearby. Things look smoother closer to Victoria, but again I'm not sure how much trust I can put in what we're seeing from this distance.

Also what I found interesting was that they labelled the image "sand sheet".

I often find it very difficult to get a proper sense of scale from rover imagery without actually doing measurements. Usually I find objects are actually smaller and distances actually closer than they appear.

So I decided to add a reference object - the profile of a "mystery man" - to some images. The profile is 2 metres tall from bottom of boots to top of raised hand. For this sol 884 pancam shot of Beagle, I put a man on the near and far rims, and also one much closer at about 24 metres range. The rim distance measurements are from an orbital map (which agreed to within about 5 or 10% with AlgorimancerPG), and the near measurement is using AlgorimancerPG.

Those foreground dunes are really small, and there are some really big chunks embedded in the far rim!
Click to view attachment

That's a very helpful view, fredk.

Here is a context view of the lone Pancam image of the "sand sheet":

Bit of a phil-o-stretch on the sand sheet image.

D

Here is an "MMB AutoPan" of Sol 885-887:



What is an "MMB AutoPan," you might be asking yourself? It's a slightly kludgy combination of the MMB panorama feature and Autostitch. The advantage over a regular Autostitched panorama is that you can see Pancam images overlaid on the Navcam background - like in this case there is the "Sand Sheet" Pancam and a small color section of "Jesse Chisholm" (if you look close), in context. Also some Navcam sky images are put in context, which you usually won't see with a regular Autostitch. I need to refine my technique a bit, but my thought was to turn these into Quicktime VR panoramas, if I can figure out how.

Here is Sol 878-883: