It looks like the 3rd row of the 1487 pan, that is not down yet, is of the sky. So this is a quick go at essentially the finished 6x2 image.



Click image

James

Ryan ( http://martianchronicles.wordpress.com/ ) said that they downlinked all the thumbnails - but then threw away the sky images They commanded a bigger mosaic than they needed, as it was commanded in the blind before the drive.

Doug

Yep, didn't want to waste bits downlinking blank sky images. I've posted the full-res false-color (uncalibrated) mosaic in my latest update: http://martianchronicles.wordpress.com/200...sols-1492-1494/

Enjoy!

There are some fresh pictures on the Exploratorium of the latest move by Opportunity during sol 1495.
The latest significant drive was on sol 1491 (check the route map) and there were two "drive attempts" after that one, on sols 1493 and 1495, both of them resulting on tiny uphill movements.
Have a look to the fhazcam shots from those sols here below (gamma corrected). Don't you think the forward left wheel is sliping and digging in the soil?

Sol 1491 (original: http://nasa.exploratorium.edu/mars/opportu...84P1212R0M1.JPG
Click to view attachment)
Sol 1493 (original: http://nasa.exploratorium.edu/mars/opportu...86P1212R0M1.JPG
Click to view attachment)
Sol 1495 (original: http://nasa.exploratorium.edu/mars/opportu...88P1212R0M1.JPG)
Click to view attachment

I'd say it is digging in, to a small depth. But of course on such a steep slope even a small amount of slippage is concerning. When you look at these images it's easy to forget about the slope and mentally "subtract it off".

On the other hand, we apparently have bedrock not far below the surface here. And the best rover drivers in the solar system at the wheel.

I have to say though that I'm surprized that it appears they intend to take a direct route to the target, over this sandy surface, rather than following the exposed rock to the left (upslope) as far as possible, before heading downslope. Perhaps they've chosen the route with the shallowest slopes.

Animation of Tesheiner's and fredk's observation.
Click to view attachment

This is going to be a long and winding road.

Astro0

> This is going to be a long and winding road.

Definitely.
Check the latest fhazcam shot from a few hours ago during sol 1496.
Click to view attachment

The original image without any "enhancements" is here: http://nasa.exploratorium.edu/mars/opportu...90P1213R0M1.JPG

Fear not, they will reach their goal. They must.

I'm not sure to be correctly interpreting the mobility data from the PCTD but based on that info I calculated the amount of slippage which happened during the driving attempts of last sols. During sol 1493, Opportunity was expected to move some 24cm but actually moved just 7cm; that corresponds to 70% slippage. During sol 1495, she was expected to move 56cm but did only 5cm; 90% slippage. There are not enough data from sol 1496 to calculate any slippage factor.

Opportunity was scheduled to move again tosol (1497). Fingers crossed.

View from Jan 11th of Oppy in Vic crater.

Nice to see her again from the sky. Is this the first pictures from Oppy inside Vicky ?

Something different. I cannot remember whether somebody already pointed out this possibility :
Would be nice to send Oppy there on the way to Cape Verde :
Edit : you'd better click on the image to see what I want to show :

Click to view attachment

That's really quite moving, seeing Oppy again from above. Brings home just how small she is, but how fearless too...!

If there is much sleepage, Oppy must move back until the platform and go to closer to Cape Verde and then go down. Not yet I have studied about the degree of transversability of the surface closer to the Cape verde.

> If there is much sleepage, Oppy must move back until the platform ...

AFAIK that's what they are trying to do, without too much success.

Hi,

Still a long time without make pictures. So, after the beautiful pan of James, I want to show mine


And a little desktop from it, with a new 16:9 format :


Bye,

Damien.

Hey Ant, Love your desktops and have had Cape St Mary as my backdrop for a long time. But why such a low resolution for your latest effort?

Thanks for the desktop image.

New pics up on exploratorium. Much close scrutiny of the surface by the pancam. Guess I'll await the panel's analysis now.

Brian

Because I was thinking that a lot of people have more 16/9 size screen than traditionnal 4/3. But, If you want, I can make a version with previous resolution I used .

Edit : for those like Aussi who prefer 1280 x 1024 px, here is a version of it : http://www.astrosurf.com/merimages/Desktop...esktop-1280.png

It looks like they may be stuck

Hi Ant,
The 16/9 sizing was great. It was just that a 6kb JPEG doesn't
provide much definition compared to (for example) the 1.7 Meg PNG in your latest 4/3.

Another attempt to free the rover from the trap (I'm wondering on a name for it...) was executed on sol 1499.
The wheels were commanded to drive for about one meter but Opportunity had a net move of less then 10cm, making for more than 90% slippage.

Prepare yourselves: the Quackmire of Duck Bay!

(He ducks, expecting to have ruffled many feathers...)

[For non-native Englishers out there, quackmire = quagmire + quack (the sound an English duck makes!)]

Seriously, though, at least some of the other wheels seem to be on pretty firm ground (right rear especially). And it won't take too many 10cm drives to get completely back on firm ground. But this certainly raises questions about getting to the base of the cliff...

Nice detail visible, even from this far away...

Click to view attachment

Quackmire. I think that will stick.

But the question is raises is not about access th the cliff, but rather why they chose to drive back across the excavated holes instead of around them. Or did they intend to go back to do an MI on the scuff and overshot through miscalculation of the slippage going downhill compared to the initial uphill withdrawal drive?

Are you sure?
Unless my eyes are playing me a trick it looks like the right-rear wheel (left on the images) is not even touching the ground but is floating.

What sort of physical situation can cause a rear wheel to come off the ground in this system, and is such a situation possible where it is?

Brian

The middle wheel digging in will do that quite easily.

Doug

If you compare the latest rhaz with some from a few sols ago you can see that the right rear has 'moved up' significantly. So it does look like the middle right has started to dig in. Conversely though, it looks like the opposite is happening on the left side which may be a good sign (slightly nervous )

James

Yikes. It looks like you're right.
You can see that fairly clearly from an anaglyph:
Click to view attachment

Good catch Fredk. I had the impression by looking at the pictures and I didn't have the idea of the analgyph. And it's clear that the rear-left wheel is above the ground. I'm wondering if it's not the middle-left wheel who is deeply inserted into the ground, and she cause an elevation on rear wheel.

The rocker bogie system is great for getting over uneven surfaces as long as they are solid. Unfortunately, there is no way to lock it (or move it) to a 6 flat wheel position for digging out of traps (sort of like 4 wheel drive on a car with differential locked to prevent slipping).

Opportunity's problem, and Spirit getting stuck in the bowl on top of home plate, may cause some re-thinking about rocker bogie designs for future rovers.
-Floyd

Next section of the latest pan...

Click to view attachment

From The Martian Chronicals:Also there are nice new versions of the Cape Verde pan on that site.

http://qt.exploratorium.edu/mars/opportuni...ABP1314R0M1.JPG

****

I'll get the low res MER model out when I get home and see what you have to do to the rocker bogie to make that happen. It's more motion than the height of the whole wheel imho.

Doug

Did the IDD stall too?

http://nasa.exploratorium.edu/mars/opportu...ABP1154R0M1.JPG

Looks R-E-A-L-L-Y high to me Doug...

Didn't the ground collapsed on Oppy's front left?...

Not front left. Middle right.

Doug

Good grief!!! That ain't right at all!!!

Good Grief...

The middle wheel must be completely covered I should think.

What the heck?!?!

Aside of the "floating" wheel, the rover is clearly tilted to the right!
Just compare the latest rhazcam picture with a similar one from sol 1496.

But the good news, looking at those two images, is that we have moved several cm up hill as indicated by the relative position of the triangular rock!

Floyd

Here're some mobility data associated to today's drive. It was executed in six consecutive steps and each of them was expected to move the rover back some 55cm for a total of 3.3meters. Opportunity moved only 22cm with an average slip factor of 93%.

Fingers crossed!

Actually - it's not as bad as I thought.

My understanding is that the rocker ( the front wheel, thru the diff, to the bogie pivot ) can rotate + / - 20 degrees. The bogie ( the rear two wheels ) can rotate + / -30 degrees. And yes - if they both go max in the same direction, the rear wheel will contact the bottom of a solar array.

BUT - on the upside - I don't think pulling a wheely like we are is as bad as all that after all. Probably about half-buried wheel.

Attached - a low fidelity sim of the RHAZ having a look, the side view of the max bogie tilt, and a movie that shows, I think, the full suspension extent.

Doug

Excellent illustration and movie, Doug!

Just goes to show what happens when you let things go around on 6 legs, instead of the 3 legs that the God of the Martians intended! H.G. Wells was right, again!

Well done, Doug, and thank you!

Man, that slip rate from the latest traverse, though...93%? Horrific. I suppose the blueberries are contributing significantly to this. Gee, why didn't the MER designers foresee them?

All humor aside, though, I think that it might well be time to ask some serious questions, as I'm sure the MER team is busily doing. If Oppy goes down there, she really might not be able to get out. The cliff is an extremely tempting and of course scientifically significant target; is this the time to roll the dice?

Hate to say it in a way, but I think the answer is yes. It would be much better to be stranded down there (God forbid) then out on the Meridiani plains with nothing, really, nearby to study. We would've killed to put one of the Vikings right where Oppy's trying to go, after all.

Having heard Steve S talking on this week's Planetary Radio show, I think it's v v unlikely there'll be any rolling of any dice. He was adamant that VC will NOT be Oppy's final resting place, that she has a lot more work to do outside, back up on the plains. For those who didn't hear the show yet - I say "yet" because everyone should go over to Emily's blog and download the show asap - SS said that they are looking at two possible "campaigns" for Oppy, post-VC. #1: "The Cobble Campaign", where Oppy would re-trace some of her tracks and go back and examine some of the interesting cobbles, stones and meteorites she scooted past in her haste to reach VC. SS said that the "Cobbles" are a very diverse mix, in great contrast to the bedrock seen by Oppy. Some are meteorites, some are ejecta from craters a long way away, and so represent samples of material deeper beneath the surface of Meridiani than seen elsewhere and so far by Oppy. He would like Oppy to go back and take a good close look at these to learn more about the sub-surface of Mars. Campaign #2 would be to go and find some more outcrops of rock and features where water came to the surface.

So, I think that if it comes down to a choice between a glorious game of Rover Roulette and a tactical if grudging withdrawl from VC, I think they'll go with the latter.

I agree there's work to do out on the plains. Does anyone have a clear idea of exactly what we might learn from an approach to Verde cliff? I mean, we have studied the layers pretty well on our traverse into Victoria so far. But judging from the imagery, the layers they talked about tasting on the cliff are quite a bit lower down than we've sampled so far? Is that all that matters here - getting lower into the layering? Or might they learn something worthwhile by looking closely at the same layers we've already tasted, but now crossing the cliff face?