Oh, wow. This doesn't bode well for Opportunity. If I am reading those CAD drawings of the rover construction properly, it could very well be high-centered over the crest of that dune it was climbing. If part or all of the weight of the rover is being supported by the underbelly of the vehicle, it will be very tricky to get get out of this location.

Luckily we have one heck of a smart team operating the rovers, and they have previous experiences that are somewhat similar.

I don't know what they should try next, but it appears the dune is only getting higher toward the south, so my best guess is to try to back out.

One observation from the hazcams has me perplexed, though. The front hazcam, which was looking toward the rear in this reverse drive, shows that Oppy was struggling for a meter or more to get into it's current position.

http://qt.exploratorium.edu/mars/opportuni...DGP1223L0M1.JPG

Shouldn't the software have detected a problem, and stopped before pushing itself into this position?

Squyres' status report for April 17 says that Oppy is in the etched terrain and that the large ripples were a sign of it. Wouldn't the rover be able to back straight out by driving on its existing tracks? If they get it unstuck, would they possibly try to drive in between the crests of the dunes to keep it on solid ground? And how would it alter their driving path to Erebus?

On a different note, it appears that Opportunity has made some good progress toward Erebus. If I had to guess, I'd say it covered about half the remaining distance since the steering problem occurred.

http://qt.exploratorium.edu/mars/opportuni...DIP2407L2M1.JPG

I think I can almost make out some outcrop ledges in that image.

I am not concerned. The rover has the capability to go on. It is not stuck. You drive back 8m and try the dune at a different angle. Remember exiting Eagle crater.

I'm not so sure, that oppy has moved much farther south - Viking and Voyager are still very well visible - http://qt.exploratorium.edu/mars/opportuni...DIP1893R0M1.JPG
There is not much differences in the navcam pictures since april 19th, so I think, that oppy is standing still, while the MiniTES related reset is being investigated.

I like it when people are optimistic. I am terribly concerned this time though. Normally, i have a lot of faith, but to me this seems by far the most serious situation oppy faced considering mobility. I don't want to be pessimistic, but anyone that has seen the wheels of his car (even a 4x4) in loose material (sand, snow, mud, whatever) this deep, knows what i am talking about.
I hope they get out, back up and think before entering this stuff again. For this reason they decided not to enter the dune-field in Endurance, remember ?

Yes, it looks like it was driving just fine until it reached this dune/ripple. I guess we'll have a better idea of what they plan on doing when the next batch of images come down.

Attempting to reach Burn's Cliff (Sol 270):

http://marsrovers.jpl.nasa.gov/gallery/all...LP1214L0M1.HTML

http://marsrovers.jpl.nasa.gov/gallery/all...5P1210R0M1.HTML


And Spirit a few sols back (Sol 453)

http://marsrovers.jpl.nasa.gov/gallery/all...GP1213L0M1.HTML

http://marsrovers.jpl.nasa.gov/gallery/all...BGP1313R0M1.JPG

At least the rear right wheel (or seeing as they were driving backwards I think - the front left wheel), it doesn't seem to be buried as much as it's opposite number.
Which is nice



And one more observation, in the images posted by dot.dk on the last page the
wheels are turned suggesting it maybe tried to do an "end of drive" turn, or something?

Not if it was a blind drive I'd say. A blind drive is just a command "go at this speed for this amount of time" isn't it ? In that case, the wheels just keep turning until the sequence is completed.

Even blind drives still have built in high water mark limits for slope, slippage and motor current etc. I'm suprised that it ploughed on as far as it did - but They'll just back out of it I'm sure - however the challenge is..

why is THIS dune so soft?

is this going to be the behaviour on dunes in the future?

what driving strategies can minimise this?

what are the best slippage, slope and currrent limits to continue driving over this stuff?

I'm sure eng. meetings are taking place almost as we speak to try and sort this out.

Doug

How many dunes, must Oppy sail / Before it sleeps in the sand?

I hear Thomas Gold's ghost cackling

In THAT case the explanation why she entered the powdery stuff this far, is because it might be of low density compared to the previous soil. I must say the texture and reflectivity does appear different to me in the last meters of the drive.

Maybe it is so loosely packed (high porosity), that oppy did not experience any change: as if the layer wasn't there. Maybe it drives ON a more firmly packed soil, 3 inches underneath, topped with powdery, fluffy material with low density/high porosity that is pushed aside very easy? Maybe the slipage like profile we see in the last meter wasn't slipping, but just a manifestation of another, new material under our feet that is easily disturbed and deformed in another way than the soil before.

I just wanted to have a crack at this....

ARB/ACM faults clear, PMA az/cam el/mtes nom, S/C att coarse, DP in Flash (D-3305) 4096, Pre ODY PCAM cal target P1424123 04, MTES_NAIF_SCLK: MTES SCLK = 1/05243365663.091.


ARB/ACM..not sure, PMA az/cam (pancam mast azimuth? camera) el/mtes nom, (electrical minites nominal? (S/C att coarse, DP in Flash (D-3305) 4096, Not sure)

Pre ODY PCAM cal target P1424123 04,(Pre Odyseey pass Pancam calibration target number...) MTES_NAIF_SCLK: MTES SCLK = 1/05243365663.091. (Minites Clk time?....... )

Just wanted to try.... prolly wrong....


hope oppy gets out soon.

John

An overview around the bad place (Navcam):

(400KB) http://www.greuti.ch/oppy/oppy-sol446-navcam-k.jpg

(950KB) http://www.greuti.ch/oppy/oppy-sol446-navcam.jpg

So where are those tire chains when we need them? Anyway, I think this is pretty serious, having some experience getting stuck in the snow belt in Ohio. The best option is back out, slowly as possible to minimize torque so thay do not bury the wheels any further.

Just a real crazy thought but if they were severely stuck, maybe they could extend the arm, plop it down deep into the soil and then PUSH their way out while driving the wheels at the same time. I know, a crazy measure, but if they are not moving anywhere for a real long time they would have nothing to loose.