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Posted by: nasaman58 Apr 29 2005, 02:44 AM

I just read on SPACE.com that Oppy managed to get all six wheels stuck deep in a sand ripple.


From the picture
http://www.space.com/php/multimedia/imagedisplay/img_display.php?pic=050428_rover_sand_02.jpg&cap=Opportunity+Mars+rover+has+encountered+deep+soil.+Credit%3A+NASA%2FJPL
the sand looks very fine grained, maybe a tad powdery. Squyers is optimistic they'll get out,
but it seems they'll have to do some rocking back and forth with prayers that they don't get in deeper. The taller ripples and the different textured sand is curious; any ideas out there as to why it gets that way farther south from the landing site?

I don't mean to be a cynic, but perhaps Oppy won't die of her own natural causes; maybe Mars, the god of war, has found prey....

Posted by: dot.dk Apr 29 2005, 02:49 AM

I guess you havn't followed the 6-7 pages on the subject here
http://www.unmannedspaceflight.com/index.php?act=ST&f=2&t=888&hl=&view=findpost&p=9426

The "news" is almost 4 days old now. But Space.com isn't that quick

Posted by: jamescanvin Apr 29 2005, 04:36 AM

I guess you havn't followed the 6-7 pages on the subject here 
http://www.unmannedspaceflight.com/index.php?act=ST&f=2&t=888&hl=&view=findpost&p=9426

The "news" is almost 4 days old now. But Space.com isn't that quick 

Posted by: Marcel Apr 29 2005, 07:08 AM

I better continue here, since Erebus and Victoria are faaaar away. Maybe we re-open it next autumn.....I couldn't sleep well last night. Maybe it is not nescessary, but the thought of a stuck rover that is functioning well got to me. Ah, we'll see, it probably is going to work out fine. Steve says so.

I used the time to do some thinking (also DVD, pay attention): the only reason why this happened has to do with the density of the material. It is considerably less dense than rocky soil, so it must be significantly higher in salt content, which is supported by the lighter colour and absence of blueberries. The white-ish mottled appearance in orbital images of the Etched terrain MUST be caused by locally elevated saltcontent of the material, instead of morphology. We're talking about physically wheatered (very finely fragmented) evaporite here! Evaporite wheathers easier than silicates, iron oxides or other mineral constituents. And that's exactly why we did not see any elevated outcrops on the way (nor on the horizon). The only outcrops we've seen is inside craters and at some points at the same level as the surrounding. The darker topsoil is definately much stronger (more resistant to wheathering) than the underlayment (evaporite). SO, i don't believe this fluffy material is global dust. It is formed in-situ.

Why ? Because there's forms of impact remnants in the white stuff on an regional scale (for example, Erebus). Therefore, the whitish material must have been there for a long time. While in the process of wheatering and levelling of, deeper parts got filled up with the darker material, mixing to some extent with the light stuff.

SO, there's only dunes here, all the way to Victoria (and probably further down). The fact that more and more (epsom?) salts are here, makes me think Oppy's on the edge of a former shoreline of some kind (lake, sea.....stream ?).

Oppy, follow the dark lanes please. It's safer !

Posted by: maycm Apr 29 2005, 12:19 PM

Steves latest update.......
from http://athena1.cornell.edu/news/mubss/

April 27, 2005

A note to all you Opportunity fans: Get used to the current scenery, because we're going to be here awhile.

We are very optimistic that we'll be able to get out of here, but we're really going to take our time doing it. The first rule in a situation like this is "do no harm", which means that you don't rush anything. We're going to take lots of pictures of all the terrain around the vehicle, to get a very complete picture of the situation. We're going to do lots of testing with the rovers that we have on the ground to simulate the situation on Mars. This testing will be aimed not just at finding a plan that will work, but at finding the very best plan that will work. We may try quite a few small maneuvers with Opportunity that aren't intended to do anything other then help us gather more information... perhaps followed by even more testing. All of this is going to take a lot of time. But this is a very precious vehicle up there, in excellent health, and there's no reason to rush anything. I'll try to provide updates as the process moves forward, but the main message for now is to be very, very patient. No apparent progress in the images doesn't mean anything other than that we're being very careful to do our jobs right.

Posted by: dvandorn Apr 29 2005, 05:20 PM

I better continue here, since Erebus and Victoria are faaaar away. Maybe we re-open it next autumn.....I couldn't sleep well last night. Maybe it is not nescessary, but the thought of a stuck rover that is functioning well got to me. Ah, we'll see, it probably is going to work out fine. Steve says so.

I used the time to do some thinking (also DVD, pay attention): the only reason why this happened has to do with the density of the material. It is considerably less dense than rocky soil, so it must be significantly higher in salt content, which is supported by the lighter colour and absence of blueberries. The white-ish mottled appearance in orbital images of the Etched terrain MUST be caused by locally elevated saltcontent of the material, instead of morphology.  We're talking about physically wheatered (very finely fragmented) evaporite here! Evaporite wheathers easier than silicates, iron oxides or other mineral constituents. And that's exactly why we did not see any elevated outcrops on the way (nor on the horizon). The only outcrops we've seen is inside craters and at some points at the same level as the surrounding. The darker topsoil is definately much stronger (more resistant to wheathering) than the underlayment (evaporite). SO, i don't believe this fluffy material is global dust. It is formed in-situ.

Why ? Because there's forms of impact remnants in the white stuff on an regional scale (for example, Erebus). Therefore, the whitish material must have been there for a long time. While in the process of wheatering and levelling of, deeper parts got filled up with the darker material, mixing to some extent with the light stuff.

SO, there's only dunes here, all the way to Victoria (and probably further down). The fact that more and more (epsom?) salts are here, makes me think Oppy's on the edge of a former shoreline of some kind (lake, sea.....stream ?).

Oppy, follow the dark lanes please. It's safer !

Posted by: djellison Apr 29 2005, 10:50 PM

http://www.unmannedspaceflight.com/doug_images/o448_tracks.jpg 580kb

Doug

Posted by: Bill Harris Apr 30 2005, 01:26 AM

Great image, Doug.

What do we see here? The duricrust seems to support the weight of the Rover as usual in the top third of the image, but apparently the wheels break through the surface and start churning after that point. The material below the surface is powdery but cohesive. One thing I don't understand is why the surface material seems to "squoosh" out from under the wheels, as in the middel of the top frame of this combinatin, and seen better in some other images.

Strange stuff. But I think this change in characteristics is significant.

--Bill

Posted by: Nix Apr 30 2005, 06:11 AM

A CRACKING image, as you would say. Terrific detail!
Bill, couldn't it be they ran the wheel in the reverse direction at the point you mentioned? Or the wheel stalled for a moment?

Posted by: Bill Harris Apr 30 2005, 11:15 AM

Something definitely happened at that point in time. As we examine and analyse (we'll have time to do that _ad_nauseam_) we'll figure out what is happening. I suspect that we've been seeing differences in the soil profile here; the soil in this part of Meridiani is very thin anyway and the "A" horizon is the ubiquitous blueberry/sand/weathering byproducts so we aren't sure of what is just beneath our wheels. I'd volunteer to do some shovel trenches, after extricating our intrepid hero...

--Bill

Posted by: Bob Shaw Apr 30 2005, 02:16 PM

I'd wager that what we're seeing in Doug's image is, at the transition between the two sorts of materials, a clod being pulled up onto the wheel and then another, then another, until suddenly the spaces between the clods start to fill and the wheel becomes wholly covered (and rather smooth). The way that there's a cyclic pattern which drops off into chaos at the end is *not* good, for it implies that the wheels are going to perform quite poorly when the time comes to try to get out of the rover-trap.

Posted by: wyogold Apr 30 2005, 07:14 PM

It almost reminds me of a snow crust. When you walk on it you are supported untill you hit a thin spot then suddenly your stuck up to your waist in a snow bank.
maybe the rover needed snow shoes.

Posted by: Tman Apr 30 2005, 08:07 PM

I sought a view of this "funny dune" that Oppy maybe took sols ago. The next sol back with useful pics that I found is sol 439. I've made a Pancam-pan from this sol therein one can find this dune. Additionally I've labeled it in a smaller image, cut from the pan - with the "exact" site of crime , where I think it is.

Panorama (720KB) http://www.greuti.ch/oppy/oppy_sol439_pancam.jpg

Cutting http://www.greuti.ch/oppy/the_funny_dune.jpg

You can compare it by the Navcam pics from sol 439 http://marsrovers.jpl.nasa.gov/gallery/all/opportunity_n439.html and by my Navcam-pan of sol 446 http://www.greuti.ch/oppy/oppy-sol446-navcam-k.jpg

Posted by: Gray Apr 30 2005, 08:07 PM

I'm not sure if anyoone has pointed this out, but if you look at the most recent front and rear hazcam images, it looks as if the rover was crossing a ripple at a very low angle. When it has crossed ripples earlier it was at an angle nearly perpendicular to the crest. The crests of the ripples are somewhat sinuous. The rover started across this one at a low angle to the crest. At about the point where the rover was crossing the crest of the ripple, the crest curved towards the left. The effect was that all of the left wheels ended up on one side of the ripple and all of the right wheels were on the other side of the crest. All six wheels ppear to be in the deepest (softest?) part of the ripple.

Posted by: Bill Harris Apr 30 2005, 10:23 PM

Posted by: David May 1 2005, 02:53 AM

Great image, Doug.

What do we see here?  The duricrust seems to support the weight of the Rover as usual in the top third of the image, but apparently the wheels break through the  surface and start churning after that point.  The material below the surface is powdery but cohesive.  One thing I don't understand is why the surface material seems to "squoosh" out from under the wheels, as in the middel of the top frame of this combinatin, and seen better in some other images.

Strange stuff.  But I think this change in characteristics is significant.

--Bill

Posted by: gregp1962 May 1 2005, 03:57 AM

I'm thinking that Doug's picture in reply #7 doesn't look like a change in consistency of soil. To me, it most definitly looks like one or more leading wheels locked up causing the trailing wheels to churn soil up and dig in.

It seems likely that a change in soil would give some indication in the adjecent, undisturbed soil.

Posted by: djellison May 1 2005, 09:12 AM

If a wheel had locked up, the rover would have stopped driving immediately - and there would be engineering data to show it happening.

That it ploughed on for a few feet into the dune, and that there is no metion of such data - rules out a 'lock up' imho

Doug

Posted by: Tman May 1 2005, 10:32 AM

One observation:  Look at you panorama and just before the scene of the crime I see an Anatolia-type of lineation immediately before the funny dune.  This may not be relevant, but I noticed this first off.  Also, there seems to be some layering in the dune just left of center.

Many clues here, Inspector Cleuseau...

--Bill

Posted by: djellison May 1 2005, 10:41 AM

Anyone whos been sailing will know you cant sail straight into wind - you have to tack. If it appears you cant drive straight over a dune - we will have to do the same I guess

so - they can simply tax along the line of the dunes, then switch back

\
/
\
/
\
/
\
/

etc

Doug

Posted by: Tman May 1 2005, 10:59 AM

I'm thinking the same, probably in future we should avoid driving over dunes.

Maybe we should ask a member of the current world power of sailing http://www.alinghi.com/en/

Posted by: Bill Harris May 1 2005, 11:51 AM

Posted by: RedSky May 1 2005, 02:00 PM

I noticed some of today's pancam sun images look like a smeared time exposure. Has anyone noticed this before? Could they be using such a technique while trying to spin the wheels in order to see how much motion they get?

http://marsrovers.jpl.nasa.gov/gallery/all/1/p/449/1P168055760ESF55DIP2620L8M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/1/p/449/1P168055760ESF55DIP2620R8M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all/1/p/449/1P168046934ESF55DIP2600R8M1.JPG

Posted by: alan May 1 2005, 02:49 PM

I've seen that before. I don't know why its that shape, maybe someone who does astrophotography could explain it.

Posted by: glennwsmith May 1 2005, 03:07 PM

I'd like to second those who are moving toward the idea that Oppy's problem is not that it has gotten stuck in a suddenly-soft patch of material, but rather that a hardware and/or software and/or command malfuntion caused it to attempt to drive with one or more sets of wheels turned in the wrong direction and/or frozen. After all, we know that Oppy HAS had a recent problem with it's right front wheel, which may be a symptom of a deeper underlying problem (electrical power distribution?) that is now beginning to affect other wheels. At any rate, this would help explain why they are taking so long to get Oppy moving again. If she were just stuck in soft material, the obvious (and perhaps only viable) response is to align all 6 wheels (in so far as possible) and attempt to back out slowly.

Doug, you are correct in saying that such a lock up should have given notice by other means -- but only IF everything else is working properly, including the human operators. In other words, given that we are nealy a year and a half into a grueling mission, do not discount the possiblity of cascading software/hardware/operator errors having caused us to stuck for a bit.

Glenn

P.S. I am quite sympathetic to the idea expressed at the beginning of this thread that a lot of water has passed under the bridge elsewhere on this topic, and that it behooves us to poke around a bit before jumping in? Hope I have followed my own advice. But of course there is also the difficulty of knowing when a new thread is appropriate -- some type of cross referencing would be cool, or maybe such already exists.

Posted by: djellison May 1 2005, 04:00 PM

The problem that oppy had was with a steering actuator - not a drive wheel.

If it had been a hardware/software error on one or more drive wheels - we'd have known about it by now - it would have come down in the very first comms pass.

Notice that BOTH sides of the vehicle have dug into the dune, and the front two and rear two wheels show evidence of having spun in situ (the tread is full of dust).

All the physical evidence shows that simply - it drove into a dune. End of story - there's evidence to suggest that it could NOT have been a hardware failure of one or more driving wheels. It would have had to have been both rear wheels ( the ones in the direction of travel) locking up to start diging the trench, but they cant have locked up or we wouldnt see their tread rendered smooth by spinning in the dust.

The reason they are taking so long to get moving again is very VERY simple. They dont want to make it worse - and to ensure that they dont - they're taking the time to do lots of remote obs and further analysis of mini-TES whilst running test-bed scenarios - arguably the only sensible progression.

Doug

Posted by: Edward Schmitz May 1 2005, 05:32 PM

On the topic of "cascading software errors", this can't happen. Software doesn't get old. Computer hardware does, but can not cause subtle changes in behaviour. This is clearly not software or computer hardware related. I design and program computer systems to control machines. There are levels of safeguards in a spacecraft that wouldn't allow a software glitch of the type being discussed.

On the topic of the problem being related to "electrical power distribution" or something similar, there are feedback to the computers that can never provide a false positive performance. The complex signals can not be mimicked by faulty hardware. If that feedback system were to fail, it would be detected and the rover would stop. Thus, none of the wheels were pointed improperly and all of the wheels were turning properly. In fact, the rover did cut it's drive short because it did detect a problem.

So the rover was doing what was expected. And Squyres is always forth coming with that type of information, anyway. The fact that it has not been stated means it didn't happen. Remember Spirit's brain freeze. They told us about and how serious it was. This is not that serious.

Being a change in the soil, it might or might not have happened. The rover could be operating properly and still not do the right thing. They are still learning how to drive with the stuck wheel. As I noted earlier, it appears that the rover may have been trying to make a left turn (with respect to the drive direction). Combine that with the stuck wheel and softer soil and maybe it was just enough to start digging in.

ed

Posted by: tacitus May 1 2005, 07:23 PM

On the topic of "cascading software errors", this can't happen.  Software doesn't get old.  Computer hardware does, but can not cause subtle changes in behaviour.  This is clearly not software or computer hardware related.  I design and program computer systems to control machines.  There are levels of safeguards in a spacecraft that wouldn't allow a software glitch of the type being discussed.
...
ed

Posted by: Edward Schmitz May 1 2005, 11:24 PM

QUOTE (Edward Schmitz @ May 1 2005, 11:32 AM)

On the topic of "cascading software errors", this can't happen.  Software doesn't get old.  Computer hardware does, but can not cause subtle changes in behaviour.  This is clearly not software or computer hardware related.  I design and program computer systems to control machines.  There are levels of safeguards in a spacecraft that wouldn't allow a software glitch of the type being discussed.
...
ed

Software doesn't get old, but programmers make mistakes. They've been tweaking the driving software for some time now, and one of the recent changes (to compensate for the drive actuator failure, I belive) did indeed cause the type of software glitch being discussed, causing the rover to veer off to the left for a few metres before the drive stopped prematurely.

Now I'm not saying that I know for sure that a software bug was to blame, but it certainly can't be ruled out yet.

Posted by: dilo May 2 2005, 06:02 AM

I've seen that before. I don't know why its that shape, maybe someone who does astrophotography could explain it.

Posted by: deglr6328 May 2 2005, 06:36 AM

QUOTE (alan @ May 1 2005, 02:49 PM)

I've seen that before. I don't know why its that shape, maybe someone who does astrophotography could explain it.

I'm almost sure they are overexposed sun images, with smear due to CCD sensor and not rover movements... However, I do not know why they overexposed pictures.

Posted by: edstrick May 2 2005, 08:50 AM

Regarding the sun images that have CCD blooming.

The purpose of the images is to measure atmosphere opacity, and to precisely locate the sun in the sky <relative to rover pancam mast camera coordinate system angles>

The exposures are commanded, not "auto-exposed". If they calculate wrong, or if the atmosphere is clearer than expected, the camera saturates pixels in the bright areas and the electrical charge in the saturated areas overflow into the non-saturated adjacent pixels.

I believe that this particular CCD <correct me if I've got this mixed with another planetary mission camera> can actually still give pretty good atmosphere opacity data from the overexposed images since the electrical charge is pretty much all there, just spread out.

Posted by: odave May 2 2005, 04:24 PM

Software doesn't get old, but programmers make mistakes. They've been tweaking the driving software for some time now, and one of the recent changes (to compensate for the drive actuator failure, I belive) did indeed cause the type of software glitch being discussed, causing the rover to veer off to the left for a few metres before the drive stopped prematurely.

Now I'm not saying that I know for sure that a software bug was to blame, but it certainly can't be ruled out yet.

Posted by: Edward Schmitz May 3 2005, 04:49 AM

QUOTE (tacitus @ May 1 2005, 03:23 PM)

Software doesn't get old, but programmers make mistakes. They've been tweaking the driving software for some time now, and one of the recent changes (to compensate for the drive actuator failure, I belive) did indeed cause the type of software glitch being discussed, causing the rover to veer off to the left for a few metres before the drive stopped prematurely.

Now I'm not saying that I know for sure that a software bug was to blame, but it certainly can't be ruled out yet.

I've a little question about software while we wait...

How in-synch do they keep Oppy and Spirit's software? I know there have been pauses for code updates in both rovers, but in general, do the tweaks made for Spirit's driving challenges remain separate from Oppy's?

I don't know what their architecture is. I'd assume that the code base for both rovers is the same, but the driving parameters/decision variables for each are different - so the slip tweaks done for Spirit are made in a "data file", which is different for Oppy. But the code that makes the decision for shutting off on a slip of X% would be the same for both. I did a quick Google and didn't find anything specific on the guts of the software.

Hopefully they don't have to manage two (slightly) different code bases for each rover. Even with the cool code management tools available now, that kind of environment can let unexpected bugs slip in.

Posted by: wyogold May 3 2005, 06:12 AM

I think we might be over thinking this. It could be simply that the riover got high centered and the new more aggressive software (for longer drives) caused it to dig itsself in. Can the wheels tell if there is slip if all 6 are slipping the same amount? Dosen't it take differences in travel to account for slip? Or maybe the rover dosen't account for slip right before it makes a turn. Was the rover making a turn when it got stuck? If it had not tried to make the turn would it be stuck right now?

scott

Posted by: V.B. May 3 2005, 06:33 AM

I have a similar question.

When djellison explained current wheel directions, he wrote:
"The wheels will be pointing in funny directions because at the end of a drive they turn the rover in place to put it in the best position for the UHF passes that afternoon and the following morning."

Does rover make turn in place at the end of drive automatically, even when it encounters an obstacle? Oppy went a half of planned day distance and sensed unexpected resistance. What instruction does she have for this issue? Is it "make turn in place for good communication"?

On the contrary, if they turn a rover by a command: did they send this command because they haven't got information about the problem yet, or did they decide to take close look at the problem after the turn?

Posted by: Sunspot May 3 2005, 09:45 AM

Id love to see what's going on at JPL with the test rover. They must be building lots of sand dunes Hopefully they'll post some pics.

http://www.pasadenastarnews.com/Stories/0,1413,206~22097~2848411,00.html

He said the earliest Opportunity would be instructed to try a maneuver that was successful in the test-bed would be Thursday for Friday

Posted by: dot.dk May 3 2005, 10:48 AM

He said the earliest Opportunity would be instructed to try a maneuver that was successful in the test-bed would be Thursday for Friday

Posted by: Marcel May 3 2005, 10:59 AM

QUOTE (Sunspot @ May 3 2005, 09:45 AM)

He said the earliest Opportunity would be instructed to try a maneuver that was successful in the test-bed would be Thursday for Friday

Does that mean they have tested a maneuver in the testbed that got the rover out of a dune?

Posted by: Bill Harris May 3 2005, 12:39 PM

Thanks for the explanations, Ed. They take much of the "black box mystique" out of the Rover software.

I wonder if one of the tweaks made to Oppy's obstacle avoidance algorithms for travel in the dunes could have made it "ignore" the dune it was on when it tried to make an end-of-drive turn in place. I imagine that the obstacle avoidance algorithm reads the hazcam/navcam images and detects shapes to avoid. A sea of dunes would present a sea of potential obstacles to avoid and the likely put less weight to avoid the dune-shapes.

She'll get out and on the road again...

--Bill

Posted by: Jeff7 May 3 2005, 01:21 PM

It is my understanding that the flight software on both rovers are identical.  The differences are going to be in settings and instructions. 

Such things as "disable steering on right, front wheel" is a setting.  Both rovers have the setting.  On one it is on and the other it is off.  The types of automated drives and manuvers that are allowed would be instructions.  They have extended the types and cababilities of drives through software updates.  There have only been two software updates that I am aware of.  They are lengthy to upload (two or three days) and a tad bit risky.  So they don't do it very often. 

The operating system for the rovers is VxWorks.  The flight software is custom written for the rovers.  The "buy-off" for a software update is not going to be trivial.  The chances of a bug slipping through are small though not negligable.  The brain freeze early in the spirit mission was caused by a bug in VxWorks.  It was not detected until spirit was near death.  The amazing thing is that the software was designed well enough that they were able to recover the vehical and fix the problem.  Having some experience with remotely maintaining and debugging machine control problems, I can say that such a recovery is a tribute to the software design.  Truly well done.

ed

Posted by: tty May 3 2005, 05:59 PM

I have a similar question.

When djellison explained current wheel directions, he wrote:
"The wheels will be pointing in funny directions because at the end of a drive they turn the rover in place to put it in the best position for the UHF passes that afternoon and the following morning."

Does rover make turn in place at the end of drive automatically, even when it encounters an obstacle? Oppy went a half of planned day distance and sensed unexpected resistance. What instruction does she have for this issue? Is it "make turn in place for good communication"?

On the contrary, if they turn a rover by a command: did they send this command because they haven't got information about the problem yet, or did they decide to take close look at the problem after the turn?

Posted by: Burmese May 3 2005, 07:09 PM

From the above-referenced article:

"The rover stopped driving when its remote sensing capabilities noticed it had not been able to make sufficient progress on a planned turn while it was driving backward."

That would seem to suggest that it still attempted a turn to help align the antenna after it had prematurely terminated the drive.

Posted by: sjdprods May 4 2005, 12:17 AM

QUOTE (dot.dk @ May 3 2005, 10:48 AM)

QUOTE (Sunspot @ May 3 2005, 09:45 AM)

He said the earliest Opportunity would be instructed to try a maneuver that was successful in the test-bed would be Thursday for Friday

Does that mean they have tested a maneuver in the testbed that got the rover out of a dune?

Um....I think so. If they did not succeed in the testbed, this statement would be premature I guess.

Posted by: MahFL May 4 2005, 12:31 AM

I also thought Oppy had tried to do the normal turn at the end of a drive, irrespective of a full drive or prematurely cut short drive. You can bet your bottom dollar that they have a manouvere that will get Oppy out of the dune

Posted by: jamescanvin May 4 2005, 01:04 AM

From the above-referenced article:

"The rover stopped driving when its remote sensing capabilities noticed it had not been able to make sufficient progress on a planned turn while it was driving backward."

That would seem to suggest that it still attempted a turn to help align the antenna after it had prematurely terminated the drive.

Posted by: Edward Schmitz May 4 2005, 05:25 AM

It definitely did not attempt a turn in place at the end of the aborted drive. When a driving anomily is encounted, all further manuovers are aborted. They were going for 90 meters, it aborted at 40 due to lack of progress, therefore it would not attempt the turn in place. That's no big loss - optimal positioning is not critical in the face of an anomily.

On the issue of why did it drive so far when it was in trouble...

They can not detect slippage in any of the wheels while they are driving. They command wheel rotations. The motors are these very powerful geared-down servos with encoders for mileage. These wheels will turn when they tell them to. Even if they are just spinning in place. Sometimes they draw more current than others, but they always go on command. Sometimes slippage can draw more current and sometimes less than normal. In addition, they can't take pics on the move. optical odometry is the only way they can detect slippage.

I think scott nailed it when he pointed to the aggressive driving software. They don't stop often enough for a look around. And these are the consiquences. That's not a complaint. It's just the risks of going fast and furious.

ed

Posted by: djellison May 4 2005, 08:03 AM

they CAN detect wheel slippage. They have inertial navigation which can be tallied with the rotation of the wheels - how else could they give us such specific slippage figures and how else would it complete a drive despite slippage occuring - such an incidednt would leave it short of the target.

And actually - I think it probably just did an end of drive wheel-wiggy just to settle itself after aborting the drive.

There is no blame to be had or pointed anywhere in this - it was probably a blind drive at the time (and 80m drive would probably be 60m + 20m autonav I'd imagine) and I can see why - all the dunes look the same and while sure - the tracks have been a little deeper over some dunes - we've not seen anything like this in more than 2km of Meridiani cruising, and there was nothing to mark out this dune as being different to any of the other 500 or so we've probably driven straight over.

Doug

Posted by: Marcel May 4 2005, 08:08 AM

It definitely did not attempt a turn in place at the end of the aborted drive.  When a driving anomily is encounted, all further manuovers are aborted.  They were going for 90 meters, it aborted at 40 due to lack of progress, therefore it would not attempt the turn in place.  That's no big loss - optimal positioning is not critical in the face of an anomily.

On the issue of why did it drive so far when it was in trouble...

They can not detect slippage in any of the wheels while they are driving.  They command wheel rotations.  The motors are these very powerful geared-down servos with encoders for mileage.  These wheels will turn when they tell them to.  Even if they are just spinning in place.  Sometimes they draw more current than others, but they always go on command.  Sometimes slippage can draw more current and sometimes less than normal.  In addition, they can't take pics on the move.  optical odometry is the only way they can detect slippage. 

I think scott nailed it when he pointed to the aggressive driving software.  They don't stop often enough for a look around.  And these are the consiquences.  That's not a complaint.  It's just the risks of going fast and furious.

ed

Posted by: JES May 4 2005, 02:03 PM

Any changes in the strategy for driving the rover will depend upon what has caused its current problem. Several questions come to mind:

What exactly caused the wheels to dig in? Did the front wheels dig in because the density of the surface material was so much less? Was the angle of attack and specific load on the wheel different in this approach than with other dunes that have been crossed? To what extent have conditions changed or was this the result of a bad combination of previous condition? Is this situation the result of unique conditions that can be avoided?

If soil deposits are building up on the rover’s approach side of the dunes only we may be able to adjust the angle of approach to float lead wheels over the softer areas with less load on the approach wheel by varying the approach angle. Assuming that the windward side of the dunes have less low density topping, it may be possible to move parallel with the waves with greater confidence. Crossing over dunes would require more guidance from home.

Do we have adequate mapping of the etched terrain to find a track through the maze that leads to the crater?

Posted by: Jeff7 May 4 2005, 02:23 PM

Any changes in the strategy for driving the rover will depend upon what has caused its current problem.  Several questions come to mind:

What exactly caused the wheels to dig in?  Did the front wheels dig in because the density of the surface material was so much less? Was the angle of attack and specific load on the wheel different in this approach than with other dunes that have been crossed?  To what extent have conditions changed or was this the result of a bad combination of previous condition? Is this situation the result of unique conditions that can be avoided?

If soil deposits are building up on the rover’s approach side of the dunes only we may be able to adjust the angle of approach to float lead wheels over the softer areas with less load on the approach wheel by varying the approach angle.  Assuming that the windward side of the dunes have less low density topping, it may be possible to move parallel with the waves with greater confidence. Crossing over dunes would require more guidance from home.

Do we have adequate mapping of the etched terrain to find a track through the maze that leads to the crater?

Posted by: gregp1962 May 4 2005, 02:55 PM

I think the picture posted by Doug http://www.unmannedspaceflight.com/doug_images/o448_tracks.jpg confirms that we didn't "suddenly run into powdery stuff". There seems to be no difference in the soil 2 feet or ten feet back.

Posted by: glennwsmith May 4 2005, 03:02 PM

I think JES may be on to something here. Does the bogie system have less compliance when moving backwards, and could this have caused the leading wheels to finally dig in rather than floating over the dunes? (This in contradition to my earlier opinion that this is a result of hardware and/or software and/or operator error, which I still hold open as a possibility.)

Posted by: djellison May 4 2005, 03:10 PM

I'd argue that the stuck steering actuator isnt related, being at the 'back' of the line of three wheels on its side of the rover. they were driving backwards remember.

Not only that but it's only a few degrees of straight-forward anyway - not much more than a bit of excessive toe-out for a racing car

Doug

Posted by: wyogold May 4 2005, 07:00 PM

After looking at all the images I really think it just got high centered. The drivers will have to provide a bit more wheel clearance when cresting dunes from now on.
Maybe somebody could point out something I'm missing but I don't see anything that "suddenly" changed in the soil.
NASA changed the rover software to provide less stops from hazards, to get longer drives which I'm sure contributed to the current situation.

she'll get out and with a bit of tweaking have long drives again (I hope)

scott

Posted by: JES May 4 2005, 09:12 PM

This picture taken before getting stuck shows the rover riding on bottom and windward side of the dune. I am assuming that prevailing winds come from the right and the lighter colored deposits on the left side of the dunes is dust settlement on the leeward edge of the crests. Since the angle of approach is very shallow, and the majority of the rover’s weight is on wheels in the trough, there would have been very little pressure on the lead wheel as it crosses the next crest. IF the angle of approach to a new crest is perpendicular, there could be additional load on the lead wheels resulting from the downhill orientation of the rover. The additional pressure could force the wheel through the surface crust, causing the wheels to dig in. The other wheels would then dig in if they continue to turn.

...
Maybe somebody could point out something I'm missing but I don't see anything that "suddenly" changed in the soil.
....
scott

Posted by: Decepticon May 5 2005, 01:35 AM

As of May 04,05 is op still stuck?

Posted by: tacitus May 5 2005, 02:03 AM

As of May 04,05 is op still stuck?

Posted by: Edward Schmitz May 5 2005, 03:38 AM

they CAN detect wheel slippage. They have inertial navigation which can be tallied with the rotation of the wheels - how else could they give us such specific slippage figures and how else would it complete a drive despite slippage occuring - such an incidednt would leave it short of the target.

And actually - I think it probably just did an end of drive wheel-wiggy just to settle itself after aborting the drive.

Doug

Posted by: Gsnorgathon May 5 2005, 07:21 AM

...
Yes - http://athena1.cornell.edu/news/mubss/.
...

Posted by: sapodilla May 9 2005, 09:36 AM

Here is a colour topography picture of the area around Opportunity. The red area is about 70cm higher than the green. The dune where Oppy is stucked is 30cm high and 2,5m wide and slope 15°. The text is in Finnish.

http://www.avaruusmgz.info/vol12/toukokuu/opportunity.html

Posted by: slinted May 9 2005, 10:53 AM

here is the JPL release, with captions:

http://photojournal.jpl.nasa.gov/catalog/PIA07922

By this view, it really doesn't look like the single dune they're currently over is the reason they dug in. The whole terrain is rising in the southerly direction (little dunes on a big dune?) and they happened to come into a rising small feature at a tilt from starting to climb the rising large feature. Also interesting to see so clearly that they aren't really plowed into the ridge headon but rather straddling it.

Posted by: gregp1962 May 9 2005, 01:26 PM

"The rover team spent more than a week designing and conducting tests under simulated Mars conditions on Earth before choosing the best way for Opportunity to drive out of the dune. "

That sounds like they have their plan and will be executing it today?

Posted by: djellison May 9 2005, 01:32 PM

I wouldnt say "today" or "this week" or "thursday" or anything to be honest. We'll see what we see, when we see it.

Remember - it's likely to be a many-sol procedure to get out of the dune - including pauses for a sol or two to look at and compare the data from short drive commands

Doug

Posted by: Burmese May 9 2005, 01:51 PM

Squyers' latest entry adds a lot of detail. Expect to see the rover do a lot of wheel spinning and soil tossing w/o moving much.

Posted by: Sunspot May 9 2005, 02:06 PM

http://www.newscientist.com/article.ns?id=dn7356

NASA could take its first steps to rescue its Opportunity rover from a Martian sand dune on Monday.

If everything continues to goes well, ground controllers will begin developing the first escape commands to send to Opportunity on Monday. The first step will be to straighten rover’s wheels, but getting the rover clear of the dune may take days, possibly even weeks.

Posted by: chris May 9 2005, 02:14 PM

Posted by: dot.dk May 9 2005, 02:20 PM

What can be done in the future to avoid running into these dunes? Can the rover planners make a guided blind drive route for Oppy to follow to avoid the worst dunes ahead by looking at navcam/pancam images?

Posted by: gregp1962 May 9 2005, 02:24 PM

Are we even sure it was the dumes that got us stuck?

Posted by: dot.dk May 9 2005, 02:28 PM

Are we even sure it was the dumes that got us stuck?

Posted by: Sunspot May 9 2005, 02:34 PM

What else? The rover was on a 90 meter blind drive and after 40 meter it just got stuck in this dune and kept spinning it wheels enough to cover the remaining distance of 50 meter. At the end of the drive it was about to perform a turn in place, but noticed it couldn't turn so it halted.

Posted by: gregp1962 May 9 2005, 03:15 PM

We can see from the images, that there wasn't a sudden change of texture of the dirt/sand,talcum powder. Also, this dune just doesn't look that more severe than others. Maybe, we were just lucky in the past.

I did notice that on Mar 22, Sunspot noticed something strange and brought it up in post #89 of this thread. Look at the wheel tracks.

http://qt.exploratorium.edu/mars/opportunity/navcam/2005-03-22/1N164774808EFF51Y2P1969L0M1.JPG

http://www.unmannedspaceflight.com/index.php?showtopic=776&st=75

Posted by: Bill Harris May 9 2005, 03:36 PM

I'm sure she'll get unstuck, but looking at the route maps posted, this difficulty was predictable.

A recent Oppy route map clearly shows a change in terrain just past the Viking/Voyager craters: the dunes become more prominent. But a hundred or so meters past that point, the dunes become more subdued, which shows another change in terrain and might suggest a more sandy surface. These changes have been subtle, but nonetheless significant.

I'll predict slow and cautious travel to Erebus, and from Erebus to Victoria.

--Bill

Posted by: Tman May 9 2005, 05:30 PM

It's been moved somewhat:

http://www.greuti.ch/oppy/oppy_hazcam_sol455-458k.gif


P.S. I dont know whether it's a correct English (German = es hat sich etwas bewegt)

Posted by: Burmese May 9 2005, 05:34 PM

I'm pretty sure they have not budged the rover. Those images just show dirt settling a bit. After all, the pancam mast is looking about and I'm sure that transmits -some- vibration down to the wheels.

Posted by: maycm May 9 2005, 05:49 PM

The wheel hasn't moved or rotated at all as far as I can see.

Some dust settling though as mentioned above

Posted by: Edward Schmitz May 10 2005, 02:36 AM

We can see from the images, that there wasn't a sudden change of texture of the dirt/sand,talcum powder. Also, this dune just doesn't look that more severe than others. Maybe, we were just lucky in the past.

I did notice that on Mar 22, Sunspot noticed something strange and brought it up in post #89 of this thread. Look at the wheel tracks.

http://qt.exploratorium.edu/mars/opportunity/navcam/2005-03-22/1N164774808EFF51Y2P1969L0M1.JPG

http://www.unmannedspaceflight.com/index.php?showtopic=776&st=75

Posted by: djellison May 11 2005, 02:56 PM

Keep an eye out on NASA TV's Video File for some great footage of the trials at the sand-box at JPL

It looked in those still images like they had the rover in a 'pit' - but there's video footage of it climbing thru and out of a fake dune - it was also just a mobility test rover - no cameras on it (to compensate for the mars-earth weight difference I presume)

It would SEEM - based on the testing - that the easiest way 'out' is 'thru' not 'back'. Steve was right though - a LOT of wheel turning without much happening, then a very small turn in place to use the excavated dirt as a 'ramp' to drive on - and it climbed very well

Doug

Posted by: sranderson May 11 2005, 04:23 PM

If we do get to the point where nothing seems to work, the "rocking" approach should be considered. A simplified rocking would not require feedback and it does not require "free" or unpowered wheel rotation. The key concept of rocking is that a forward motion followed by an immediate reverse motion (assuming you want to go backwards) can result in a gravity assist from coming down a small ramp. This provides reverse momentum through the point where otherwise the wheels would have been stationary. Thus you get the rearward force that is applied through wheel traction, plus the gravitational momentum, at the point where otherwise you would only have wheel traction.

It is possible that one rocking motion would be sufficient. But repetitive rocking takes a hole shaped like the wheel and elongates it, building ramps on both the forward and reverse ends.

Special timing and feedback is used to optimize the rocking motion so that no digging occurs at the endpoints of the motion, but a little analysis and test can probably give enough information to pre-program this to simply minimize digging at the ends. You could even do each rocking cycle separated by a day to see how the ramp-building is coming along.

Scott

Posted by: sranderson May 11 2005, 04:40 PM

It is interesting to note that, according to this site http://www.ast.cam.ac.uk/~ipswich/Miscellaneous/Archived_spaceflight_news.htm , "On several occasions, Lunokhod 2 sank in loose rock up to the hubs of its wheels."

Scott

Posted by: Jeff7 May 11 2005, 06:15 PM

If we do get to the point where nothing seems to work, the "rocking" approach should be considered.  A simplified rocking would not require feedback and it does not require "free" or unpowered wheel rotation.  The key concept of rocking is that a forward motion followed by an immediate reverse motion (assuming you want to go backwards) can result in a gravity assist from coming down a small ramp.  This provides reverse momentum through the point where otherwise the wheels would have been stationary.  Thus you get the rearward force that is applied through wheel traction, plus the gravitational momentum, at the point where otherwise you would only have wheel traction. 

It is possible that one rocking motion would be sufficient.  But repetitive rocking takes a hole shaped like the wheel and elongates it, building ramps on both the forward and reverse ends.

Special timing and feedback is used to optimize the rocking motion so that no digging occurs at the endpoints of the motion, but a little analysis and test can probably give enough information to pre-program this to simply minimize digging at the ends.  You could even do each rocking cycle separated by a day to see how the ramp-building is coming along.

Scott

Posted by: dot.dk May 11 2005, 06:42 PM

The immediate problem I see with that though is that rocking requires that the motors have some speed behind them. These wheels don't seem like they are meant for anything closely resembling speed.

Posted by: JES May 11 2005, 07:28 PM

....
It is possible that one rocking motion would be sufficient.  But repetitive rocking takes a hole shaped like the wheel and elongates it, building ramps on both the forward and reverse ends.
.....

Posted by: sranderson May 11 2005, 08:58 PM

QUOTE (sranderson @ May 11 2005, 12:23 PM)

....
It is possible that one rocking motion would be sufficient.  But repetitive rocking takes a hole shaped like the wheel and elongates it, building ramps on both the forward and reverse ends.
.....

Could repeated forward and backwards movements also further compress the current wheel pit, setting the rover deeper into the soil?

Posted by: Sunspot May 12 2005, 12:04 AM

The wheels have been straightened

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-11/1F169113996EFF55DJP1214L0M1.JPG

http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-05-11/1R169114032EFF55DJP1314L0M1.JPG

Posted by: dot.dk May 12 2005, 12:12 AM

The wheels have been straightened

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-11/1F169113996EFF55DJP1214L0M1.JPG

http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-05-11/1R169114032EFF55DJP1314L0M1.JPG

Posted by: dot.dk May 12 2005, 01:04 AM

Look at these two Pancam pictures

http://qt.exploratorium.edu/mars/opportunity/pancam/2005-05-11/1P169112544EFF55DIP2131R1M1.JPG

http://qt.exploratorium.edu/mars/opportunity/pancam/2005-05-11/1P169114095EFF55DJP2131R1M1.JPG

The last one is after the front wheel has been straightened.

To me the bottom of that trough looks pretty firm

Posted by: Stephen May 12 2005, 09:11 AM

Look at these two Pancam pictures

http://qt.exploratorium.edu/mars/opportunity/pancam/2005-05-11/1P169112544EFF55DIP2131R1M1.JPG

http://qt.exploratorium.edu/mars/opportunity/pancam/2005-05-11/1P169114095EFF55DJP2131R1M1.JPG

The last one is after the front wheel has been straightened.

To me the bottom of that trough looks pretty firm 

Posted by: djellison May 12 2005, 09:14 AM

Well - Thursday was touted as a possible day of action - and so that would tie in with yesterdays straight-wheel move - I guess we'll find out what the first step is over the next 24-48 hrs.

I've got a crate of mars bars that says people at Mark Carey's forum, the Habitable Zone and elsewhere WILL - despite the repeated warnings from Steve - brand the exit attempt a complete failure after one sol

Doug

Posted by: OWW May 12 2005, 10:14 AM

I've got a crate of mars bars that says people at Mark Carey's forum, the Habitable Zone and elsewhere WILL - despite the repeated warnings from Steve - brand the exit attempt a complete failure after one sol

Doug

Posted by: Bill Harris May 12 2005, 12:28 PM

Posted by: ustrax May 12 2005, 01:40 PM

QUOTE (djellison @ May 12 2005, 09:14 AM)

I've got a crate of mars bars that says people at Mark Carey's forum, the Habitable Zone and elsewhere WILL - despite the repeated warnings from Steve - brand the exit attempt a complete failure after one sol

Doug

Of course. But isn't it possible for Spirit to help out Oppy? The drive attempt will be a failure because the wheels are stuck in either mud, fossils or eyesockets of skulls. But most likely it was all a trap designed by intelligent martians. It's quite obvious when you look at the geometric layout of the dunes. Look:

Posted by: GADean May 13 2005, 01:14 AM

A heads up for y'all. I just returned from a talk by Dr. Albert Haldemann, a Deputy Project Scientist on the MER team. Most of what he presented would be old news for this group, but he did mention that their sandbox testing for Oppy consistently shows that a straight reverse out of the dune is their best option . They think it might involve a lot of wheel spinning to back all the way out, and they will take it in stages.

After yesterday's wheel straightening they may well wait for the weekend to pass before they send up commands for a "couple of meters" of wheel turning. They don't expect to get nearly that much actual movement. It took about 60 meters of wheel spinning to dig them in, he said, and it could take that much and more to get out.

The slow approach is not all caution, according to Heldemann. They are curious about the change in soil characteristics, if there has been one, and they want to see how this soil behaves as they churn it up a bit. In response to a question he mentioned that a current "best guess" as to why they went deep into this dune is a combination of locally larger dunes (actually "drifts", he corrected), the configuration of this particular drift... getting aligned with the rover, and the gentle rise in the terrain. Apparently they are driving slightly uphill.

He didn't seem the least concerned that they wouldn't get out, and saw this as a good learning experience while the really cool geology was happening over at Gusev.

Oh...and apparently the JPL people like the "blue sunset" picture as much as we do.

BTW: He mentioned that they are looking for a few more folks for the science team. "Get your proposals in!" is how he put it.

Posted by: dot.dk May 13 2005, 01:48 AM

After yesterday's wheel straightening they may well wait for the weekend to pass before they send up commands for a "couple of meters" of wheel turning.

Posted by: GADean May 13 2005, 05:52 AM

QUOTE (GADean @ May 13 2005, 01:14 AM)

After yesterday's wheel straightening they may well wait for the weekend to pass before they send up commands for a "couple of meters" of wheel turning.

God damn, I can't wait the whole weekend before Oppy makes her next move. Was really excited to see new pictures at exploratorium, but it was day old pictures

Why wait until after the weekend? Haven't they done all the testing they need to do? Why not send the command now and spend the weekend looking at the result??

Posted by: AndyG May 13 2005, 08:33 AM

...I also got the sense that one reason it takes so long is that the team is smaller and not running 24/7 these days.

Posted by: tuomio May 13 2005, 03:50 PM

Yeah, but they have to maximize the support for future landers. They are doing great with current funds and i dont see what good would increased budget do. As we have seen, the rovers lifetime is probably limited to how much miles it racks up, not how much time it spends idling. Atleast in 2 years span that is. Probably biggest time critical component is the battery, it will wear out from the constant natural charcing/recharging cycles at some point. It would be interesting if there was public access to the rovers health stats.

Posted by: Sunspot May 13 2005, 11:37 PM

http://marsrovers.jpl.nasa.gov/mission/status.html#opportunity

OPPORTUNITY UPDATE: Opportunity Mission Manager Report for Sols 456-463 - sol 456-463, May 13, 2005

Opportunity has started moving its wheels again after a couple weeks of holding still while taking some amazing images. While waiting for the rover team to finish tests for planning the best strategy for driving out of a sand trap, Opportunity has been busy taking a comprehensive color panorama of the area. On sol 461 (May 11), Opportunity straightened its wheels. After checking data and images confirming the success of that move, the team planned commands for beginning to rotate the wheels on sol 463 (May 13). The rover is healthy and ready to go.

Sol 461:
Today Opportunity was allowed to position its wheels to their egress direction. The plan is for the rover to leave the sand trap with an arc, moving forward and slightly to the left. The wheels were placed in that position. Before this sol's steering move, the wheels were in position from a turn in place that was Opportunity's last attempted move on sol 446.

Posted by: dot.dk May 13 2005, 11:41 PM

From the same report:

Sol 463 (May 13):
After confirming the new position of the wheels, the team proceeded with plans for Opportunity to rotate its wheels about two and a half times on sol 463. Results from that move will be evaluated before rotating them some more.

So they have send the command, just waiting to see the result

Posted by: marsman May 13 2005, 11:47 PM

Yeah, but they have to maximize the support for future landers. They are doing great with current funds and i dont see what good would increased budget do. As we have seen, the rovers lifetime is probably limited to how much miles it racks up, not how much time it spends idling. Atleast in 2 years span that is. Probably biggest time critical component is the battery, it will wear out from the constant natural charcing/recharging cycles at some point. It would be interesting if there was public access to the rovers health stats.

Posted by: dot.dk May 14 2005, 01:06 AM

New hazcams up!!

http://qt.exploratorium.edu:16080/mars/opportunity/forward_hazcam/2005-05-13/1F169294630EFF55E3P1214L0M1.JPG

http://qt.exploratorium.edu:16080/mars/opportunity/rear_hazcam/2005-05-13/1R169294697EFF55E3P1314R0M1.JPG

Don't know what I think... Just be very carefull

Posted by: dot.dk May 14 2005, 01:28 AM

Some gifs

Left


Right


Lot's of spinning, but both wheels are climbing. The right one a bit better than the left.

Posted by: deglr6328 May 14 2005, 01:43 AM

Well at least it looks like the caking in between the ridges isn't totally solid. It looks like it's falling out in different sections with every revolution so as long as that's happening it should be able to grab more dirt with every turn....

Posted by: dot.dk May 14 2005, 01:50 AM

Looks very encouraging at the back

Posted by: Bubbinski May 14 2005, 02:38 AM

Very nice animations, dot.dk. That's encouraging to see about the dirt coming off the wheel treads....I think they'll be out of there fairly soon.

Posted by: glennwsmith May 14 2005, 03:28 AM

Yes, dot.dk, THANKS for posting the animations -- way cool. It is hilarious -- in a way -- to see Oppy in the same situation on Mars we have all been in on earth.

Glenn

Posted by: CosmicRocker May 14 2005, 03:51 AM

Woohoo! This is truly encouraging. Those animations are wonderful. Thanks, dot.dk. Quite a lot can be observed in them. The wheels are definately displacing the soil from in front and moving it under the wheels as Steve Squyres predicted. It looks as if Oppy has advanced several centimeters after only 2.5 rotations of the wheels.

Posted by: CosmicRocker May 14 2005, 03:56 AM

Oh yeah. I also checked the times the hazcam images were taken using rawid. It looks as if the whole sequence took about an hour and 13 minutes to execute.

Posted by: Sunspot May 14 2005, 09:14 AM

It also looks like the rover has risen up out of the soil slightly too.

Posted by: Jeff7 May 14 2005, 02:11 PM

Assuming it gets out, which it looks like it should manage to do, it's going to be quite interesting driving now. It went from a flat plain to a maze.

Posted by: Bubbinski May 14 2005, 02:35 PM

I thought about that last night....what are they going to do when they get unstuck? I suspect they'll need to drive between the dunes. And if the dunes cross the plain more in an east-west direction than in a north-south direction.....say goodbye to Erebus and hello to the terrain north of Endurance? Or go west or east toward someplace else? Just speculating here, I'm no expert.

Posted by: dot.dk May 14 2005, 02:37 PM

Just drive as much as possible between the dunes and cross them where they look safe...

Posted by: dilo May 14 2005, 02:53 PM

It also looks like the rover has risen up out of the soil slightly too. 

Posted by: lyford May 14 2005, 04:43 PM

Assuming it gets out, which it looks like it should manage to do, it's going to be quite interesting driving now. It went from a flat plain to a maze.

Posted by: Sunspot May 14 2005, 04:57 PM

dot.dk...... looking at your animation, I get the impression the wheel has moved forward slightly rather than down.

Posted by: Edward Schmitz May 14 2005, 05:08 PM

When you say front, I presume you meant rear. The front of the rover and forward drive direction are now back to the same.

When the rover got stuck, the rear was in the forward drive direction. In that configuration, the front wheels would tend to dig deeper. Now that the drive direction is reversed, the rear wheels are the ones that should be digging in. If that's what's happening (It's hard for me to tell), then it wouldn't be alarming to me. Especially if they are making forward progress. Which they seem to be.

I think that there is a relatively hard surface under the dune. If there wasn't, I think that the 50 meters of wheel turning would have been fatal. I don't think they can take that risk again. They have the software on board to keep this from happening. I'm sure they will be using it to their advantage in the future.

All of the images and movies look like what I was expecting. I am confident that it will be clear of the dune in the near future.

Speaking of mazes, I think they could develop the software to recognize the dune crests and run between them. Right now, the software only recognizes vertical relief that posses a collision or slope hazard. I don't think it would be that hard to modify that logic to identify dune crests. Just steer between them. The good news is that the dune crests are more or less aligned with the drive direction.

ed

Posted by: Tman May 14 2005, 05:15 PM

Sad to say, vertical movement brings final elevation slightly worse than initial one, as showed in the following comparison with an image taken 2 Sols before... :

Posted by: dvandorn May 14 2005, 06:41 PM

By combining informations from all wheels time lapse, rover succesfully moved back only in its the left side; right side back movement was smaller and this should have slight changed azimuth orientation of the rover, as confirmed by these two two Navcam images taken approximately at the start (top) and the end of operation (presumably with unchanged pointing)...

Obviously, also roll angle is changed...

Posted by: dvandorn May 14 2005, 06:49 PM

I thought about that last night....what are they going to do when they get unstuck?  I suspect they'll need to drive between the dunes.  And if the dunes cross the plain more in an east-west direction than in a north-south direction.....say goodbye to Erebus and hello to the terrain north of Endurance?  Or go west or east toward someplace else?  Just speculating here, I'm no expert.

Posted by: jaredGalen May 14 2005, 10:11 PM

Latest report says
"In the loose footing, the rover advanced 2.8 centimeters (1.1 inch) forward, 4.8 millimeters (0.19 inch) sideways and 4.6 millimeters (0.18 inch) downward"

Posted by: CosmicRocker May 15 2005, 12:32 AM

Wow. It is absolutely amazing to me that they feel confident to report the changes in position down to the tenth of a milimeter!

There was other interesting information in that update:
--The results were a good match to the tests.
--We may yet see a repeat performance today.

Posted by: Hynee May 15 2005, 01:10 AM

Posted by: tacitus May 15 2005, 04:09 AM

QUOTE (GADean @ May 13 2005, 11:14 AM)

A heads up for y'all. I just returned from a talk by Dr. Albert Haldemann, a Deputy Project Scientist on the MER team...
... It took about 60 meters of wheel spinning to dig them in, he said, and it could take that much and more to get out.

That's shocking, it "drove" for 60 m without realising it was stuck. Why didn't the visual odometry trigger an error? Was this what was expected to happen if it got stuck as it did, or was there an unexpected hardware/software failure?

Posted by: CosmicRocker May 15 2005, 04:51 AM

...watching and waiting for Oppy's Act 2...It doesn't look like we'll see it tonight, though. I would have been happy to see another tenth of a millimeter or so.

While looking for something to do, I noticed there was a sequence of navcams from yestersol's movement. Here is an animated view from the top of the mast.

Posted by: dilo May 15 2005, 05:16 AM

Latest report says
"In the loose footing, the rover advanced 2.8 centimeters (1.1 inch) forward, 4.8 millimeters (0.19 inch) sideways and 4.6 millimeters (0.18 inch) downward"

Posted by: Edward Schmitz May 15 2005, 06:22 AM

...watching and waiting for Oppy's Act 2...It doesn't look like we'll see it tonight, though.  I would have been happy to see another tenth of a millimeter or so. 

While looking for something to do, I noticed there was a sequence of navcams from yestersol's movement.  Here is an animated view from the top of the mast.

Posted by: jaredGalen May 15 2005, 11:12 AM

Posted by: garybeau May 15 2005, 11:33 AM

Do you think the consistency of the soil is any different at night when Mars is at
it's coldest verses during the day time? It may be better to try a couple of rotations
of the wheels at night. As far as I know, all of the testing was done at room temperature.

Posted by: jaredGalen May 15 2005, 12:12 PM

Do you think the consistency of the soil is any different at night when Mars is at
it's coldest verses during the day time? It may be better to try a couple of rotations
of the wheels at night. As far as I know, all of the testing was done at room temperature.

Posted by: garybeau May 15 2005, 02:13 PM

I thought about this a while back too. I guess it all depends on what exactly is in the soil that could freeze with night time temps. If anything....

Posted by: Tman May 15 2005, 06:29 PM

Did anyone notice...

There seems to be two small pieces of dirty that collapse on the rover's tracks on the left side of the video.  I would guess that it must have been caused by vibrations from the rover movement.  I am surprised that it could do that.

Posted by: dvandorn May 15 2005, 06:46 PM

QUOTE (jaredGalen @ May 15 2005, 07:12 AM)

I thought about this a while back too. I guess it all depends on what exactly is in the soil that could freeze with night time temps. If anything....

What made me bring this up, I remember on one of the Apollo missions they had a very difficult time retrieving a core sample. I don't recall hearing an explanation for this. Was it because the soil was compacted just below the surface or did it have something to do with the extremely cold temperatures just below the surface? We know from the sample returns that there was no moisture involved. Something similar must be going on in the dunes on Mars. The daytime temperatures probably warms up the top couple of inches near the surface, but just a few inches below that, the temperature is probably pretty close to the average day time/night time temperatures which would be very cold. The fact that Oppy didn't bury itself any deeper than what it did, tells me the soil must be a lot harder just below the surface. Is temperature a factor in this?

Gary

Posted by: dilo May 15 2005, 06:48 PM

Posted by: Edward Schmitz May 15 2005, 08:30 PM

I tend to think that there is hard surface under the dune.

Two reasons.

One, it didn't sink endlessly. Why wouldn't it? The powder has got to have an extremely low density. As light as the rover is, it could not possibly be floating on this stuff. The deeper it got, the more it would dig down rather than forward. I've had a similar experience when I was trying to drive across a paved road covered in about six inches of sand. Many revs for little forward progress. It's all about scooping it from the front and moving it to the back - in tiny amounts. Without the pavement below, I would have just sank (and did when my wheels got off the pavement).

Two, the alleged vibation induced collapse. I do clearly see two collapse events that happen on separate frames. I've heard others disagree - that it might be shadows - but I'm convinced they are collapses. As to them being vibration induced... I'm not convinced. But consider that the rover was sitting there for about two weeks with only the most minor soil changes. Then in the space of a little over an hour, two events occur just when the rover is moving.

I have to agree with DILO that the collapses are due to vibrations that must be being transmitted through an under lying denser layer. If the vibrations were transmitted through the top layer, it would have disrupted matterial closer to the rover.

One additional point, what's up with that test fixture with the tarps? The powder matterial doesn't look very deep. Might just be the pictures, but maybe they wanted to simulate an underlying firm layer because that is their assesment of the conditions.

Posted by: dilo May 15 2005, 09:26 PM

Yes Edward, absolutely not shadows! they are collapsed during "first act" and is hard to believe that is a coincidence...!
Exploratorium just published PandCam of collapsed region with higher resolution and more favorable illumination conditions (Sol464); the stereo view (crossed eyes again) is very cool :
http://img252.echo.cx/my.php?image=1p169374346eff55e3p2269r2m16iv.jpg

Posted by: garybeau May 15 2005, 09:54 PM

Posted by: maycm May 16 2005, 12:17 PM

Have we made a significant move?

Not sure what I am looking at here....

Posted by: djellison May 16 2005, 12:47 PM

Yup - another few CM forward i'd say

It'll be a bit of a fiddle - but I'm going to try and do a composite animation that has all four corners animated together - for the whole egress - in one animation. Who knows if it'll work - but it'll be fun trying


Doug

Posted by: maycm May 16 2005, 01:14 PM

Looks like the wheel is at right angles to the previous track....

Posted by: Bill Harris May 16 2005, 01:17 PM

Posted by: garybeau May 16 2005, 01:40 PM

Sol 465 animations.

http://i6.photobucket.com/albums/y207/garybeau/Sol465RR.gif

http://i6.photobucket.com/albums/y207/garybeau/Sol465RF.gif

http://i6.photobucket.com/albums/y207/garybeau/Sol465LR.gif

http://i6.photobucket.com/albums/y207/garybeau/Sol465LF.gif

Looks like it is going to be a long slow process getting out of here. I wonder if getting back over the dune is going to be a problem. It looks like they are trying to make a 90 degree crossover.

Posted by: djellison May 16 2005, 01:49 PM

Those anims are SUPERB Gary - nicely done

Doug

Posted by: glennwsmith May 16 2005, 02:06 PM

She's a' movin' !

And I'll second Doug on thanking Gary for these nice animations.

Glenn

Posted by: David S. May 16 2005, 03:51 PM

Thanks a lot for the anims, they are great ! And it looks very promising

Posted by: Nirgal May 16 2005, 04:25 PM

Thanks a lot for those fantastic animations !
give's you the feel of being there ... seeing this poor spinning wheels
it's hard to resist the urge to
help Oppy in just extendig the hand and give it a strong push

I have one question regarding the total time span covered by the
spinning animations:

in the JPL report they spoke about "just 2 and a half wheel revolutions"
Now this would be very, very reassuring !

On the other hand, looking at the shadows in the images, could it be that the
spinning actually took place during perhaps several hours.... (???)

anyone shed light on this ?

Posted by: dot.dk May 16 2005, 04:40 PM

in the JPL report they spoke about "just  2 and a half wheel revolutions"
Now this would be very, very reassuring !

On the other hand, looking at the shadows in the images, could it be that the
spinning actually took place during perhaps several hours.... (???)

anyone shed light on this ?

Posted by: Tman May 16 2005, 05:07 PM

I have one question regarding the total time span covered by the
spinning animations:

Posted by: Nirgal May 16 2005, 05:28 PM

Thanks Tman !

didn't know that the motors have the capability to do fractions of wheels turns ...
It makes sense: step-wise motion would be the most prudent approach.
(although it probably doesn't simulate the "ineratia effects" of continuous motion)
Anyway I'd say the situation looks pretty good: with forward progress at all
even after only a couple of wheel turns... not what you are used to from your typical stuck-with-the-car-in-the-snow kind of wheel spinning experience

Posted by: MizarKey May 16 2005, 05:34 PM

After watching Tman's animation in slow-mo, I was having a hard time telling which way the wheel was turning. Well, to be honest, I could see it turning both ways if I tried. If I guessed I would say it was spinning 'backward' or 'counterclockwise' as that would be the most logical direction.

Eric P / MizarKey

Posted by: dilo May 16 2005, 07:52 PM

Have we made a significant move?

Not sure what I am looking at here....

Posted by: Tman May 16 2005, 08:12 PM

Hey, Edward, did you noticed again it?  It seems another small material collapse, now on the other (right) track...!

Posted by: alan May 16 2005, 09:18 PM

So far the wheel thats moved the most is the right front wheel, its now where it was before Oppy attempted to turn after the drive an sol 446. It appears that what they've accomplished so far is to reallign Oppy with its tracks. Hopefully we will see progress on both sides next time.

Posted by: djellison May 16 2005, 10:01 PM

I dont think they're going to try and back out all the way down the trenches they churned on the way in - that churned material is softer and probably offers less traction that 'virgin' ground. I think, given the FR wheels 7 deg toe-out, they will do an arcing turn off to the left.

Doug

Posted by: dilo May 16 2005, 10:59 PM

This is and enhanced version of poor-quality left/back wheel movements in both days (463 and 465); click to see it:
http://img224.echo.cx/my.php?image=leftbackwheel0np.gif
Is clear that there was further digging on this side, counterbalanced by very good movement of opposite wheel... I made also more complex animation containing the four wheels in both days (same idea from Doug project ), but I'm not able to publish it ! (ImageSack do not allow files>1M, can someone suggest best way?).

Posted by: lyford May 16 2005, 11:26 PM

More info from http://athena.cornell.edu/news/mubss/

Posted by: Sunspot May 16 2005, 11:26 PM

New update from Steve Squyres:

http://athena1.cornell.edu/news/mubss/

The rover moved more than a centimeter in the expected direction during each maneuver, which was just the kind of behavior we were hoping for. (In fact, the motion was actually more than I was personally expecting to see this early in the game.)

Posted by: dot.dk May 16 2005, 11:35 PM

He also said they will drive the wheels for 4 meters today. The last 2 have been 2 meter drives.

Ahh well, there goes my night again waiting for the new pics

Posted by: Edward Schmitz May 17 2005, 02:45 AM

Hey, Edward, did you noticed again it?  It seems another small material collapse, now on the other (right) track...!

Posted by: Edward Schmitz May 17 2005, 03:04 AM

Wow. It's really moving. I had faith it would - but there is no substitude for reality. Well good, we'll be on the road again in no time. (maybe that's a little too optimistic)

The additional collapse is convincing me that the rover motion is causing it. I wonder what the rover team is making of them. Wonder if they find it significant...

Posted by: alan May 17 2005, 07:01 PM

New article in New Scientist

Optimism as Mars rover edges towards freedom

"NASA’s Mars rover Opportunity has begun its long march out of the sandy dune in which it got stuck on 25 April. Ground controllers have got it to move more than four centimetres since Friday - considered a big victory.
The space agency’s Mars rover team tried to recreate the conditions that halted Opportunity when it dug itself into a Martian drift. In Earth-based tests, engineers buried an identical rover’s wheels in a specially designed sandy mixture. In those tests, the rover’s wheels turned many times before it was able to pull itself out of the soil.
So on Mars, ground controllers expected soil to shift from the front to the rear of the rover, but they did not expect Opportunity to move right away. They commanded the wheels to rotate 2.5 times and as they turned Opportunity crept forward by 2.8 cm.
“We may have just made it a harder problem on the ground than what we see on Mars,” says Jim Erickson, rover project manager for NASA’s Jet Propulsion Laboratory in Pasadena, California, US. "

http://www.newscientist.com/article.ns?id=dn737

Posted by: RonJones May 17 2005, 07:09 PM

Opportunity progressed another 1.1 inches on the third drive (with twice the number of wheel rotations). Info from today's JPL MER web site update.

Ron Jones

Posted by: RNeuhaus May 18 2005, 01:22 AM

Opportunity progressed another 1.1 inches on the third drive (with twice the number of wheel rotations).  Info from today's  JPL MER web site update.

Ron Jones

Posted by: Pando May 18 2005, 01:38 AM

Good suggestions RNeuhaus, although on your points 4 and 5 I'd like to point out that whatever minute momentum Oppy has will not help here -- its wheels are completely gear-driven (i.e. there is no clutch), and it really moves extremely slow compared to any dune buggy here on earth...

Posted by: dot.dk May 18 2005, 04:40 AM

Another day, another inch forward

made some animations of the progress so far:

Front:
http://img280.echo.cx/my.php?image=moveall7zi.gif

Rear:
http://img280.echo.cx/my.php?image=moveallback7tb.gif

Also another thought that crossed my mind. Is it impossible to do more than one drive a day? I would imagine they could do if they used direct to Earth communication.

It would really help to get this job done quicker. Execute the first drive, wait for the result, and if it is looking ok, execute the next one.

Posted by: CosmicRocker May 18 2005, 05:35 AM

dot.dk: What an excellent idea, to rock the animations back and forth. It's too bad we are not getting all of the 'in between' images lately, but I am getting the sense that Opportunity is making very good progress.

Kudos are due to the scientists and engineers on the team for doing what we all knew they could do when we dicovered Opportunity was in this predicament. Perhaps we should send them a case of Mars Bars when she is clearly out of danger.

Posted by: djellison May 18 2005, 07:00 AM

If someone knows an appropriate JPL address that will actually get to them - I'll sort out a card or a little pressie or something

Doug

Posted by: Tman May 18 2005, 11:01 AM

If someone knows an appropriate JPL address that will actually get to them  - I'll sort out a card or a little pressie or something

Doug

Posted by: djellison May 18 2005, 11:20 AM

I was thinking more getting a little garden trowel - painting it up with some gold spray paint - and sending it to the engineering team as a thank-you gesture for all the digging they've been doing in the mars-yard

Then again - last time I did anything like that was a little beagle 2 christmas card that I rendered to look like B2 stuck under snow from overyone at the old Beagle 2 yahoo group I started in '02. I dropped it off at the space centre here in Leicester, and Beagle was never heard from again Maybe I'm cursed.


Doug

Posted by: dot.dk May 18 2005, 11:30 AM

Looks like it's animation time again

Warning! Slow loading....

Front Left:


Front Right:


Rear Left:


Rear Right:

Posted by: Nirgal May 18 2005, 11:44 AM

absolutely love those animations, dot.dk !!

it's almost like live TV coverage from Mars

Posted by: Marcel May 18 2005, 12:07 PM

absolutely love those animations, dot.dk !!

it's almost like live TV coverage from Mars

Posted by: dot.dk May 18 2005, 12:09 PM

These are great animations indeed ! I don't like to see though that the rear wheels seem to dig in even deeper. Hope she doesn't get stuck on her WEB !

Posted by: Marcel May 18 2005, 12:12 PM

QUOTE (Marcel @ May 18 2005, 12:07 PM)

These are great animations indeed ! I don't like to see though that the rear wheels seem to dig in even deeper. Hope she doesn't get stuck on her WEB !

Only the right one seems to go a bit deeper, but would the nature of the Rocker-Bogie Suspension system not indicate that the middle wheel is rising then?

Posted by: Burmese May 18 2005, 12:16 PM

I can't tell that the chassis sunk in at all. I wouldn't worry too much. When that wheel gets to the dirt pile that the middle wheel ahead of it has been churning up, we should see some lift.

On a side note, I suspect the people who study soil composition are having a field day with those 'animations' showing in great detail how the sand responds to the wheels on a minute by minute basis.

Posted by: djellison May 18 2005, 12:17 PM

But the WEB ( and thus the Hazcams ) dont appear to be getting closer to the surface - so I think it's fair to say that perhaps yes - the middle wheels are rising a little

I've run all front hazcam driving all together as one long animation...

Front Left
http://www.unmannedspaceflight.com/doug_images/FL.gif
800kb

Front Right
http://www.unmannedspaceflight.com/doug_images/FR.gif
450kb

I'll keep adding to them, and make a .mov of all four corners when they're out

Doug

Posted by: Marcel May 18 2005, 12:42 PM

On a side note, I suspect the people who study soil composition are having a field day with those 'animations' showing in great detail how the sand responds to the wheels on a minute by minute basis.

Posted by: Tman May 18 2005, 01:11 PM

I've run all front hazcam driving all together as one long animation...

I'll keep adding to them, and make a .mov of all four corners when they're out

Doug

Posted by: RNeuhaus May 18 2005, 02:39 PM

According to the last motion pictures, I am convinced that Opportunity will get out of stuck sand. It is approaching to the decline slope and also a more compact sand in which they will help to MERS B to come out of a situation with flying colours.

On that point. the motion must be keeping rotating enough distance until the MERS B reach to the point where the sand is flatter and more compact.

After the MERS is alive, I am doubting if the MERS is capable to distinguish by myself to the different type of sand in order to avoid that the future will happen again?

Rodolfo

Posted by: Marslauncher May 18 2005, 03:22 PM

Do we have any power numbers for Oppy? Surely sat there the power levels must be down, we prolly need to get a cleaning event on oppy soon.

I think I saw in one of Steve's reports he said something like 500w/hrs...

I could be wrong.

Posted by: Pando May 18 2005, 04:01 PM

I've run all front hazcam driving all together as one long animation...

Front Left
http://www.unmannedspaceflight.com/doug_images/FL.gif
800kb

Front Right
http://www.unmannedspaceflight.com/doug_images/FR.gif
450kb

Posted by: helvick May 18 2005, 04:01 PM

Do we have any power numbers for Oppy? Surely sat there the power levels must be down, we prolly need to get a cleaning event on oppy soon.

I think I saw in one of Steve's reports he said something like 500w/hrs...

I could be wrong.

Posted by: Pando May 18 2005, 04:08 PM

Do we have any power numbers for Oppy? Surely sat there the power levels must be down, we prolly need to get a cleaning event on oppy soon.

I think I saw in one of Steve's reports he said something like 500w/hrs...

I could be wrong.

Posted by: Nirgal May 18 2005, 04:20 PM

Posted by: helvick May 18 2005, 07:47 PM

Posted by: Nirgal May 18 2005, 09:37 PM

great work helvick !

your graph is exactly what I had in mind when I wrote the post above

So, with the frequency of "cleaning events" observed so far
(3 per 300 rover sols) there is reasonable hope to get at least one more
cleaning before the next critical 600-700 sol mark ...
-> really putting the 1000 sol mark in reach

Posted by: djellison May 18 2005, 10:35 PM

Am I the only one thinking "damnit - if they get to 1000 sols, i'll have to rename all my folders"



As someone called it previously - perhaps we may even reach the S1K problem

Doug

Posted by: garybeau May 18 2005, 10:52 PM

Beautifull chart helvick, you must have way too much free time on your hands



gary

Posted by: helvick May 18 2005, 11:25 PM

Beautifull chart helvick, you must have way too much free time on your hands

gary

Posted by: Nirgal May 18 2005, 11:36 PM

Excel really isn't very useful for graphing things like this - anyone got any recommendations for any software that can make decent looking charts?

Posted by: Edward Schmitz May 19 2005, 01:46 AM

QUOTE (Marcel @ May 18 2005, 12:07 PM)

These are great animations indeed ! I don't like to see though that the rear wheels seem to dig in even deeper. Hope she doesn't get stuck on her WEB !

Only the right one seems to go a bit deeper, but would the nature of the Rocker-Bogie Suspension system not indicate that the middle wheel is rising then?

Posted by: dot.dk May 20 2005, 02:42 AM

After the 8 meter drive yesterday, how are we looking for today? Another 8 meter?

Posted by: dot.dk May 20 2005, 05:39 AM

Another day, another cm

Here is an animation of all Oppys movement so far:

http://img281.echo.cx/my.php?image=moveallfronthaz4699ew.gif

And from the back

http://img272.echo.cx/my.php?image=moveallrearhaz4694kc.gif

Posted by: Marslauncher May 20 2005, 02:36 PM

wow thats a really awesome animation you got there would be nice if it would go a little faster though (not the animation just the overall progress of extraction for Oppy)

Posted by: dot.dk May 21 2005, 01:21 AM

New JPL update.

Posted by: tacitus May 21 2005, 02:07 AM

That's pretty consistent at 0.5cm per metre so far.

Posted by: alan May 21 2005, 03:12 AM

Posted by: dot.dk May 21 2005, 03:58 AM

I was just playing around with the Rocker-Bogie suspension to see if I could mimic the rear right wheel sinking so much.

Got this:

http://img267.echo.cx/my.php?image=oppybogie5zg.gif

Don't know if it is accurate in any way

Posted by: alan May 21 2005, 05:12 AM

Rear wheels are getting in deep
http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-05-20/1R169914111EFF55HHP1314R0M1.JPG

Posted by: dot.dk May 21 2005, 05:13 AM

Yeah, but we are really making good progress now! We will be out soon!

Posted by: dot.dk May 21 2005, 05:28 AM

The usual...

Front:
http://img269.echo.cx/my.php?image=moveallfronthaz4705lb.gif

Rear:
http://img269.echo.cx/my.php?image=moveallrearhaz4703ym.gif

Posted by: Sunspot May 21 2005, 09:50 AM

Rear wheels are getting in deep
http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-05-20/1R169914111EFF55HHP1314R0M1.JPG

Posted by: akuo May 21 2005, 10:00 AM

I wonder if they really are sinking in after all.  If you look at that picture in detail, there appears to be a dune crest rising up slightly near the right wheel.  However, it also appears to be dropping off as we get to see more of it and as Opportubity moves slowly forward. 

Posted by: Sunspot May 21 2005, 10:07 AM

oops...I meant to say that I dont think it is sinking in that much after all......it might "look" that way because the soil has been rising up near the right wheel because of the dune crest that has become visible. I think it is now dropping away again.

So the latest images that appear at exploratorium show the result of the planned 12m drive?

Posted by: TheChemist May 21 2005, 03:02 PM

Are these tracks made from Oppy ? Or something else ?

http://qt.exploratorium.edu:16080/mars/opportunity/pancam/2005-05-21/1P169914275EFF55HHP2134L2M1.JPG

Posted by: dot.dk May 21 2005, 03:19 PM

Are these tracks made from Oppy ? Or something else ? 

http://qt.exploratorium.edu:16080/mars/opportunity/pancam/2005-05-21/1P169914275EFF55HHP2134L2M1.JPG

Posted by: garybeau May 21 2005, 03:20 PM

Are these tracks made from Oppy ? Or something else ? 

http://qt.exploratorium.edu:16080/mars/opportunity/pancam/2005-05-21/1P169914275EFF55HHP2134L2M1.JPG

Posted by: alan May 21 2005, 03:20 PM

Are these tracks made from Oppy ? Or something else ? 

http://qt.exploratorium.edu:16080/mars/opportunity/pancam/2005-05-21/1P169914275EFF55HHP2134L2M1.JPG

Posted by: dot.dk May 21 2005, 03:25 PM

If you compare this Pancam SOL 469
http://marsrover.nasa.gov/gallery/all/1/p/469/1P169824476EFF55H5P2134L2M1.JPG

With this SOL 470
http://marsrover.nasa.gov/gallery/all/1/p/470/1P169914275EFF55HHP2134L2M1.JPG

We can clearly see how good the progress is getting now

Posted by: TheChemist May 21 2005, 03:46 PM

I should have known better, this is the Nth time this happens to me.
The minute I read garybeau mentioning a 180o rotated image, I realized I was fooled once more
I guess I should not look at MER imaging while working

Thanks to everyone for their comments.

Posted by: Tman May 21 2005, 04:21 PM

That is the track that Oppy made just before getting stuck. Because of the lighting direction, some of the image features can look inverted. (at least for me anyway)
Here is the same image rotated 180 degrees.

http://i6.photobucket.com/albums/y207/garybeau/1P169914275EFF55HHP2134L2M1.jpg

Gary

Posted by: dilo May 21 2005, 09:12 PM

In a German astronomy forum there is a woman who is specialising in this phenomenon of inverted views. So far the poor woman isn't able to look for craters in moon pictures - she has only hills in her mind 

Posted by: Bob Shaw May 21 2005, 10:18 PM

Personally, I've found that a life-time enthusiasm for 'top shelf' gentlemen's magazines has assisted me enormously in my stereo perception... ...even in non-stereo images!

Seriously, though, it's surprising how many people just don't seem able to do the crossed-eye trick at all. Perhaps when we see the IMAX-3D MER special there'll be the opportunity (geddit?) to seduce a few more folk to the 3D camp!

Well, I *hope* there's an IMAX 3D MER film coming...

Posted by: dilo May 21 2005, 11:17 PM

Personally, I've found that a life-time enthusiasm for 'top shelf' gentlemen's magazines has assisted me enormously in my stereo perception... ...even in non-stereo images!

Seriously, though, it's surprising how many people just don't seem able to do the crossed-eye trick at all. Perhaps when we see the IMAX-3D MER special there'll be the opportunity (geddit?) to seduce a few more folk to the 3D camp!

Well, I *hope* there's an IMAX 3D MER film coming...

Posted by: edstrick May 22 2005, 09:19 AM

About 10% of the population is more or less Stereo-Blind, about the same fraction that has some form of color-blindness. I have amblyopia and cannot fuse images to get stereoscopic perception at all. Bit of a pain for a one time <and still amateur> planetary geologist.

Posted by: Nix May 22 2005, 12:47 PM

I tried for 4 months and then one day it worked. It's very simple really and I think more people should try it. But I must say I haven't been able to learn it to friends and such.. stereomadness..
Nico

Posted by: Jeff7 May 22 2005, 02:48 PM

QUOTE (TheChemist @ May 21 2005, 10:02 AM)

Are these tracks made from Oppy ? Or something else ? 

http://qt.exploratorium.edu:16080/mars/opportunity/pancam/2005-05-21/1P169914275EFF55HHP2134L2M1.JPG

That is the track that Oppy made just before getting stuck. Because of the lighting direction, some of the image features can look inverted. (at least for me anyway)
Here is the same image rotated 180 degrees.

http://i6.photobucket.com/albums/y207/garybeau/1P169914275EFF55HHP2134L2M1.jpg

Gary

Posted by: TheChemist May 22 2005, 02:59 PM

Under certain light conditions in an image, I may look at it and confuse intrusions with protrusions.
If I don't realize it immediately, the image looks strange and incomprehensible. A rotation by 180o of the image restores my perception of depth (and whatever is dysfunctional in my brain ) , and I can see the image for what it really is.

Posted by: dot.dk May 22 2005, 03:09 PM

Before we get to far OT here...

What do you think will be the next moves in the extraction process?

Posted by: JRehling May 22 2005, 06:40 PM

QUOTE (Tman @ May 21 2005, 04:21 PM)

In a German astronomy forum there is a woman who is specialising in this phenomenon of inverted views. So far the poor woman isn't able to look for craters in moon pictures - she has only hills in her mind 

I experienced exactly the same problem for many years when I was younger; I had to patiently educate (force) my mind to invert images to correct this tendency (however, sometimes happens again! ).
I'm convinced that, years later, this "discipline" helped me to efficently see stereograms, especially crossed-eyes ones; many other peoples aren't able to do this unnatural operation...
I'm curious about other experiences!

Posted by: bluemars1 May 22 2005, 07:55 PM

Forgive me for the previous blank post. Yes I am definitely a newbie. I was going to suggest that it would be nice to get back on-topic, but it appears I have just exacerbated the problem.

To answer the previous on-topic post, If I were skiing, I'd trudge out of the this crust-covered fluff, and traverse in the valleys as much as possible. Since the rovers don't have the benefit of momentum, they'll have to test every crossing dune very gingerly (e.g. command a meter, visually sense slip, change direction if necessary). I think it's going to be slow stuff (<20 meters/day type progress).

I can't wait until we send humans to orbit Mars and remotely control an entire fleet of rovers in real time. Even these rovers would be about 10x more productive. I will die a happy man if I see that in my lifetime. (oops, I changed topics...er.. Curses! Hoisted on my own petard!)

Posted by: Sunspot May 22 2005, 11:43 PM

The rover has moved quite a bit overall:

http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-05-22/1R170002842EFF55HTP1314R0M1.JPG

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-22/1F170002791EFF55HTP1214R0M1.JPG

It does appear to be digging it's way out... I wonder if this is what happened during testing on Earth?

Posted by: mhall May 23 2005, 07:21 AM

I'm distinctly worried that, when it reaches the end of the gardened, churned-up tracks, Opportunity will just continue swimming through the soft dusty undersoil. I can't see that there will be an 'edge' that the wheels can catch on, to lift out of the dust layer.

Put another way: breaking through the permacrust was like going through a thin sheet of ice on top of a swamp. It may be that the rover is doomed to stay in the swamp, progress being made by just nibbling away at the crust without climbing up on it again.

Of course, the stuff at the base of the dune may be better going, more compacted, easier to climb up on. I certainly hope so.

-- Martin

Posted by: Sunspot May 23 2005, 08:55 AM

That was something that I thought about too. As the dune slopes downwards though perhaps there will come a point where, particualrly if the rover doesn't sink any more, the wheels are less buried in the soil and they will drive up out of the trenches they've made.

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-22/1F169914059EFF55HHP1214R0M1.JPG

Posted by: dot.dk May 23 2005, 09:16 AM

If you look at the last drive the right front wheel is already starting to rise and I believe that is a sign of what to come very soon

The left is going a bit down though, but it also has the most dirt to shovel

http://img262.echo.cx/my.php?image=4704711za.gif

Posted by: djellison May 23 2005, 09:19 AM

I've been trying to understand the 'means' of entry in getting stuck - based on the fact that the front and rear wheels track just about together - and the middle wheels are about 1/3rd of a wheels-width inboard of that. It's plausable that they're not nearly as dug in, but that they're not taking much of the load. It would be interesting to see some graphics based on the articulation of the rocker/bogie (they have this data, it has been reconstructed into movies in the past)

Doug

Posted by: mars_armer May 23 2005, 02:54 PM

In the attached images, the blue position is the original "stuck" position, and the overlaid positions are after drives on sols 463-468.

Posted by: djellison May 23 2005, 03:59 PM

There we go - THAT's what I'm talking about Middle wheel is nowhere near as deep as the rest.


Doug

Posted by: Tesheiner May 23 2005, 04:43 PM

In the attached images, the blue position is the original "stuck" position, and the overlaid positions are after drives on sols 463-468.

Posted by: dot.dk May 23 2005, 05:03 PM

Now that's some cool stuff

Looks like my idea of the bogie movement was correct

Didn't Oppy drive today?

Posted by: Deeman May 23 2005, 05:11 PM

Oppy seems to move faster with a bit more grip on Sols 470-471. Looks good to me

Posted by: Deeman May 23 2005, 05:13 PM

and the right one as well

Dirk

Posted by: dilo May 23 2005, 08:10 PM

Agree, is clearly accelerating now!
Look for example to this animation of back/right wheel in the last 4 days (using only half of frames):
http://img74.echo.cx/img74/4821/sol467471rr8dv.gif
Go, Oppy, go!

Posted by: Jeff7 May 23 2005, 11:27 PM

In the attached images, the blue position is the original "stuck" position, and the overlaid positions are after drives on sols 463-468.

Posted by: jamescanvin May 24 2005, 02:19 AM

In the attached images, the blue position is the original "stuck" position, and the overlaid positions are after drives on sols 463-468.

Posted by: Sunspot May 24 2005, 10:11 AM

It would be interesting to know how long it took the test rover to escape the drift, and whether it behaved in a similar way to what we are seeing with Opportunity right now.

Did it continue to "dig" through the soil like Oppoertunity is doing....or after a few sols did it drive up out of the trenches on to the surface.

Posted by: JES May 24 2005, 05:58 PM

The amount of fill in the left wheel trench is greater than that in the right without any spill to the sides. Does this reflect :

different volumes of material due to different densities before they were disturbed,

deeper pentration by the right wheel below the surface,

better traction on the left wheel moving more material forward as it backs out.

or is there a larger pile of loose material in the way of the right wheel as it continues to back out?

Posted by: maycm May 24 2005, 06:29 PM

I thought I read somewhere that they were reversing out in an arc, in which case one side would move more than the other.

Posted by: djellison May 24 2005, 07:06 PM

Yes - instead of trying to fight the 7 degree toe-out on that FR wheel, i think they're 'giving in' to it and letting the rover turn to the left as it pushes back

If they were to go straight back down their own trenches, the wheels could end up just churning all the way. By turning the craft a little to 'push' against the left side of the trenches, it gives them something 'new' to have a bite at and pull up out the trenches I guess.

Doug

Posted by: tuomio May 24 2005, 10:57 PM

The rear wheels seem to dig themselfs deeper all the time, which is bit alarming. I dont think it means the middle wheels are getting higher, but they both get down as they churn forward. I do not yet think they are on the clear waters even than there is accelerating movement. As they dont actually gather any momentum because the speed is so slow, progress might stop just as quick as it started.

Posted by: dvandorn May 24 2005, 11:43 PM

Yes - instead of trying to fight the 7 degree toe-out on that FR wheel, i think they're 'giving in' to it and letting the rover turn to the left as it pushes back

If they were to go straight back down their own trenches, the wheels could end up just churning all the way. By turning the craft a little to 'push' against the left side of the trenches, it gives them something 'new' to have a bite at and pull up out the trenches I guess.

Doug

Posted by: dot.dk May 25 2005, 05:48 AM

From: http://www.space.com/missionlaunches/050524_rovers_update.html

Posted by: jaredGalen May 25 2005, 07:02 AM

Thr first image in oppy's rear_hazcam page for today the 25th gave me quite a jump.

What the!! Where, what!!! Ooooooohhhhhh.
http://qt.exploratorium.edu:16080/mars/opportunity/rear_hazcam/2005-05-24/1R145228445EFF34BJP1311L0M1.JPG

And this is wonderful!!
http://qt.exploratorium.edu:16080/mars/opportunity/forward_hazcam/2005-05-24/1F145332673EFF3500P1214L0M1.JPG

Posted by: Pando May 25 2005, 07:14 AM

Looking back at those images, it's a relief that Oppy didn't venture into the dune trap in the middle of Endurance. We realize this now how dangerous this would have been.

Posted by: Mode5 May 25 2005, 08:26 AM

Thr first image in oppy's rear_hazcam page for today the 25th gave me quite a jump.

What the!! Where, what!!! Ooooooohhhhhh.
http://qt.exploratorium.edu:16080/mars/opportunity/rear_hazcam/2005-05-24/1R145228445EFF34BJP1311L0M1.JPG

And this is wonderful!! 
http://qt.exploratorium.edu:16080/mars/opportunity/forward_hazcam/2005-05-24/1F145332673EFF3500P1214L0M1.JPG

Posted by: dot.dk May 25 2005, 08:32 AM

At least some genuine new images just came down...

Still making good progress

http://qt.exploratorium.edu:16080/mars/opportunity/forward_hazcam/2005-05-25/1F170271356EFF55IZP1214R0M1.JPG

http://qt.exploratorium.edu:16080/mars/opportunity/rear_hazcam/2005-05-25/1R170271407EFF55IZP1314R0M1.JPG

Posted by: Sunspot May 25 2005, 08:52 AM

From: http://www.space.com/missionlaunches/050524_rovers_update.html

QUOTE

At the current rate, it may be two more weeks before Opportunity once again reaches safe ground, Erickson added.

Let's hope the rate picks up soon

Posted by: djellison May 25 2005, 08:57 AM

I wouldnt say less optimistic. Clearly they still think they can get out - and saying it'll take a week, or two weeks, is consistant with the progress we've been making and consistant with the predictions from Steve.

Doug

Posted by: dot.dk May 25 2005, 09:00 AM

He also said:

Posted by: SFJCody May 25 2005, 11:52 AM

Posted by: Trader May 25 2005, 05:41 PM

"I was looking some image sent from 'today' which shows it still on the lander. It's amazing they didn't transmit and purge these earlier with the mem problems. "

Could one conclude that the massive downloads of the last few days were intended to lighten the rover and assist in getting her unstuck?

Posted by: Mode5 May 25 2005, 10:25 PM

"I was looking some image sent from 'today' which shows it still on the lander. It's amazing they didn't transmit and purge these earlier with the mem problems. "

Could one conclude that the massive downloads of the last few days were intended to lighten the rover and assist in getting her unstuck?  

Posted by: Burmese May 26 2005, 12:25 PM

More steady progress. Is it my imagination or does Oppy have a slight forward tilt now?

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-26/1F170361977EFF55K7P1214L0M1.JPG

http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-05-26/1R170362029EFF55K7P1314L0M1.JPG

The right front wheel seems to be rising, despite being set in the deeper part of the dune - perhaps the solid ground below rises a bit at that point.

Posted by: dot.dk May 26 2005, 12:45 PM

Animation of todays drive:

http://img165.echo.cx/my.php?image=frontright4759lu.gif

http://img239.echo.cx/my.php?image=frontleft4759by.gif

http://img239.echo.cx/my.php?image=rearright4753rk.gif

http://img239.echo.cx/my.php?image=rearleft4751lo.gif

Posted by: JES May 26 2005, 12:46 PM

......If they were to go straight back down their own trenches, the wheels could end up just churning all the way. By turning the craft a little to 'push' against the left side of the trenches, it gives them something 'new' to have a bite at and pull up out the trenches I guess.

Doug

Posted by: maycm May 26 2005, 07:10 PM

Apologies if this has already been posted.

Here's a polar shot of Oppys present-ish position.



There's a medium res version http://www.jpl.nasa.gov/images/mer/2005-05-06/1NN448EFF55-med.jpg

Posted by: dot.dk May 27 2005, 09:30 AM

Interesting! In todays drive they seem to have turned the left front wheel slightly, perhaps the same amount as the 7 degree as the right front.

Posted by: Marcel May 27 2005, 09:35 AM

Interesting! In todays drive they seem to have turned the left front wheel slightly, perhaps the same amount as the 7 degree as the right front.

Posted by: Sunspot May 27 2005, 10:12 AM

How would you rate Opportunity's progress so far? Do you think things are going well or not?

It's interesting (as others have pointed out) that the rover doesn't seem to be rising up out of the soil. I wonder if the depth of the rear wheels is preventing the front wheels from climbing up out of the trenches.

Posted by: Tesheiner May 27 2005, 10:25 AM

Posted by: Marcel May 27 2005, 11:13 AM

How would you rate Opportunity's progress so far? Do you think things are going well or not?

Posted by: Cugel May 27 2005, 11:22 AM

I'm new to this topic, so maybe it has been discussed before, however...
As I understand it the problem that Oppy is now in resulted not so much from getting stuck in the dune field, but more in persistent rotation of the wheels when the rover was actually not moving forward. I believe I have read somewhere that the rover got stuck roughly halfway in a long range drive, so after 40 or 50 meters in a 100 meter drive.
However, once it got stuck the software failed to notice this and simply 'completed' the drive. (Correct me if I'm wrong about this) I think this caused the wheels to really dig in deep, which is why it is so difficult to get out afterwards. Had the software stopped the wheels on time, the rover would have backed out much more easily. If this assumption is correct it would mean that driving deeper into the Etched Terrain would not be that risky, with the software properly configured that is... Or is this a bit too optimistic from my side?

Posted by: Marcel May 27 2005, 12:05 PM

I'm new to this topic, so maybe it has been discussed before, however...
As I understand it the problem that Oppy is now in resulted not so much from getting stuck in the dune field, but more in persistent rotation of the wheels when the rover was actually not moving forward. I believe I have read somewhere that the rover got stuck roughly halfway in a long range drive, so after 40 or 50 meters in a 100 meter drive.
However, once it got stuck the software failed to notice this and simply 'completed' the drive. (Correct me if I'm wrong about this) I think this caused the wheels to really dig in deep, which is why it is so difficult to get out afterwards. Had the software stopped the wheels on time, the rover would have backed out much more easily. If this assumption is correct it would mean that driving deeper into the Etched Terrain would not be that risky, with the software properly configured that is...  Or is this a bit too optimistic from my side?

Posted by: Cugel May 27 2005, 12:57 PM

QUOTE (Cugel @ May 27 2005, 11:22 AM)

I'm new to this topic, so maybe it has been discussed before, however...
As I understand it the problem that Oppy is now in resulted not so much from getting stuck in the dune field, but more in persistent rotation of the wheels when the rover was actually not moving forward. I believe I have read somewhere that the rover got stuck roughly halfway in a long range drive, so after 40 or 50 meters in a 100 meter drive.
However, once it got stuck the software failed to notice this and simply 'completed' the drive. (Correct me if I'm wrong about this) I think this caused the wheels to really dig in deep, which is why it is so difficult to get out afterwards. Had the software stopped the wheels on time, the rover would have backed out much more easily. If this assumption is correct it would mean that driving deeper into the Etched Terrain would not be that risky, with the software properly configured that is...  Or is this a bit too optimistic from my side?

Yes, Cugel, this has been discussed before. Detecting slippage is only possible in autonomous navigation mode. This digging in probably happened during a blind drive command.

What i was wondering however: They KNOW where they came from in the last drive that ended in this deep. They KNOW at which point they started slipping from imagery. Subtract these distances and you'll get the ratio between wheel motion and actual displacement within this horrendous last meters. This gives us the function that has been posted earlier this threat.

What i was wondering: is this function while digging in the same as it is now, while trying to get out again ? If it is, i am confident that in the end she'll get out within the same amount of wheel revolutions as it took her to get in.

Then there's only one question left for me: how many meters was the commanded drive that got her in the deep ? This might give me the opportunity to win the mars bar in the other threat.......by guessing the sol she'll be up and running again !

Posted by: dvandorn May 27 2005, 01:20 PM

Then there's only one question left for me: how many meters was the commanded drive that got her in the deep ? This might give me the opportunity to win the mars bar in the other threat.......by guessing the sol she'll be up and running again !

Posted by: Marcel May 27 2005, 01:40 PM

By the way, I don't think that digging in can be considered the reversal of digging out.

Posted by: dot.dk May 27 2005, 03:51 PM

According to this:
http://www.space.com/imageoftheday/image_of_day_050527.html

Opportunity has now spun it's wheels for 48 meters and gained about 28 cm.

But the interesting thing in the image is that apparently the difference between the red and green areas is 70 cm!!

It's really not easy to see this big difference from the cameras on the rover because of the uniform terrain.
This means the difference between the area just in front of the rover and the area just behind it has a 70 cm difference in height!

No wonder it got stuck

Posted by: CosmicRocker May 28 2005, 07:27 AM

dot.dk: Good catch on the wheel turn. That 70 cm of elevation change is also interesting news. I am guessing that they have already compensated for the right turn Opportunity made as it ploughed into this dune, and they now want to turn into the trough on the way back out.

Others have wondered how the progress has been so far. I posted some graphs of progress efficiency in another thread.

http://www.unmannedspaceflight.com/index.php?showtopic=1008&view=findpost&p=11238

In retrospect, I probably should have posted them here.

The plots display centimeters advanced versus meters attempted, and include data published by JPL and the recent article from space.com. The going has not been getting any better (as we all can see), but the data is a few sols old. As others have pointed out, the latest data point from space.com indicates that 48 meters of attempted driving has occurred, and Opportunity has not gone as far back as she had previously ploughed ahead in 50 meters of attmpted driving.

At least she is still making progress, but I really was expecting progress to get better by now. I would sure like to get some newer data to add to the plots.

Posted by: dilo May 28 2005, 07:33 AM

Last 12 days progress from both hazcam full frames (right):
http://img283.echo.cx/my.php?image=rearhazcamr6sp.gif
http://img290.echo.cx/my.php?image=fronthazcamsmall8yx.gif
(sorry for poor quality, but there are restrictions on postable GIF files size )

Posted by: Sunspot May 28 2005, 09:11 AM

WOW..........lots of forward progress, interesting how the depth to which the wheels are buried seems to stay the same.

The front right wheel has the stuck steering actuator, if at some point it rises up out of the trench a little more, do you think they would attempt to turn the rover?

Posted by: CosmicRocker May 28 2005, 06:07 PM

Steve Squyres has a new update out today. It's longer than usual, too. Only one paragraph on Opportunity, pretty much confirming what the plots showed. There is a lot of good stuff on Spirit, though.

http://athena1.cornell.edu/news/mubss/

"Nothing really new at Meridiani. We're seeing slow, steady progress, at a remarkably constant rate. For ever meter of wheel turns that we command, we get half a centimeter of actual motion. It's been like this since the start of the extraction process. We're typically doing 12 meters of wheel turns a day, and typically seeing about six centimeters of motion. We'll get out of here eventually, but it's a slow, laborious process."

Posted by: alan May 28 2005, 09:09 PM

Interesting! In todays drive they seem to have turned the left front wheel slightly, perhaps the same amount as the 7 degree as the right front.

Posted by: dilo May 30 2005, 06:17 AM

The left front wheel appeared to be getting bogged down before they made the turn. It seems to be making better progress now. Rubbing against the side of the trench must have been slowing it down.

Posted by: Mode5 May 30 2005, 08:46 AM

Thank you for putting that together.

Am I the only one to find this excruciating to watch? I just want to walk over to it, pick it up and send it on its way. The pictures really put this struggle into perspective. I find myself viewing that, clenching my fists and saying to myself, "go, go!".

Looking at the lower edge, which is very well defined, it does appear that they are moving slightly out of the track.

Posted by: Tman May 30 2005, 02:07 PM

Hi dilo, I've allowed me to continue your animation from May 28:

http://www.greuti.ch/oppy/oppy_front_sol460-479.gif

I think we have circa arrived the point where Oppy's middle wheels (and rear wheels?) sinked. Hopefully the front wheels become raised now in next sols.

Posted by: dilo May 30 2005, 05:34 PM

Hi dilo, I've allowed me to continue your animation from May 28:

http://www.greuti.ch/oppy/oppy_front_sol460-479.gif

I think we have circa arrived the point where Oppy's middle wheels (and rear wheels?) sinked. Hopefully the front wheels become raised now in next sols.

Posted by: Richard Trigaux May 30 2005, 08:27 PM

Does anyone noted that the bogging starts, not when the slope of the current dune begins, but at the end of the descending slope of the previous dune.

This can lead to a new explanation of what happened:

1) when Oppy was on the previous dune, she found a descending slope with an angle greater than all the previous
2) arriving at the bottom of this dune, due to her very inclinated position, Oppy nosed into the sand
3) due to nosing, the leading wheels began to dig into the ground
4) due to leading wheels into the ground, the rear wheels began digging
5) then Oppy was unable to recover a safe position, especially when the ascention of the current dune began.

Posted by: Edward Schmitz May 30 2005, 08:50 PM

removed un-necessary quoting - see http://www.unmannedspaceflight.com/index.php?showtopic=988 :Doug
No, the slippage did not occur until it was acsending the next dune. The front wheels (it was going backward) were at the bottom but the rear wheels were well up the next dune. All the wheels started slipping at the same time. You can't have the two forward wheels getting stuck and still have the other four making progress.

Posted by: Tesheiner May 31 2005, 04:52 PM

Hi all,

On this image you can see the (approximate) position of the left wheel on Sols 472 and 479, based on the front hazcam "movies".
The background picture is of Sol 461.

Currently there is no official report about the actual progress after sol 475, but my estimation for 472-479 is around 27cm net advance.

Tesheiner

Posted by: Sunspot May 31 2005, 06:43 PM

If you take a close look at this latest hazcam image you can see the track of what i assume was the middle wheel - which stayed on the surface and didnt trench in to the soil as soon as the other wheels (front wheel?)

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-31/1F170805634EFF55RGP1214L0M1.JPG

As the rover moves forward, some of the soil must be pushed to the sides - I wonder what will happen when it meets the trench from the single wheel track?

Posted by: mhoward Jun 1 2005, 03:10 PM

It looks to me like Oppy made better progress on Sol 481. It's a little harder to see in the forward hazcam images until you look carefully at the landmarks, but it's quite obvious in the rear hazcam. Maybe we will finally be out of this drift soon???

Posted by: Tesheiner Jun 1 2005, 03:21 PM

Oppy were commanded on previous sols (476-480) to 12m drives executed in 30 steps of 0.4m.
Today's drive is different. Less steps (actually 10, from RG to S0) but bigger ones.

And as mhoward noted, better progress.
I should add that the forward left wheel was turned again a bit to the right .

Tesheiner

Posted by: dot.dk Jun 1 2005, 03:23 PM

Latest hazcam pics looks VERY good!

Both the left/right rear and front left is rising! The rear wheels must have reached were the middle wheels started now.

Go Oppy Go!

Posted by: Tesheiner Jun 1 2005, 03:30 PM

Oppy were commanded on previous sols (476-480) to 12m drives executed in 30 steps of 0.4m.
Today's drive is different. Less steps (actually 10, from RG to S0) but bigger ones.

And as mhoward noted, better progress.
I should add that the forward left wheel was turned again a bit to the right .

Tesheiner

Posted by: Burmese Jun 1 2005, 03:47 PM

Yes, I think just a few more days and we can consider Oppy free. But can they do anything to clear the treads? Some of that stuff looks like it intends to stick around, at least until they can roll over som bare rock.

Posted by: Sunspot Jun 2 2005, 12:40 PM

Certainly the most the rover has moved in a single sol so far.....it looks like slightly more than one wheel diametre.

Sol 480: http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-05-31/1F170805634EFF55RGP1214L0M1.JPG

Sol 481: http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-06-01/1F170891965EFF55S0P1214L0M1.JPG

If the front wheel wasn't stuck they could probably try a turn in place.

Posted by: Tesheiner Jun 2 2005, 01:24 PM

IMO, yesterday's move has a net advance of around 12cm i.e. one wheel radius, about twice the amount of previous days.

Posted by: Tman Jun 2 2005, 01:30 PM

It's going more and more exciting - climb or not climb?! Come on, front wheels!

http://qt.exploratorium.edu/mars/opportunity/forward_hazcam/2005-06-02/1F170982695EFF55SKP1214L0M1.JPG

But I think, they will hampered by the other slipping wheels.

Posted by: Bill Harris Jun 2 2005, 02:47 PM

My guess is that progress will pick up once Oppy gets out of the interdunal area and onto the backside of the dune ahead.

We'll see what we see when we see it...

--Bill

Posted by: OWW Jun 2 2005, 03:54 PM

My guess is that Oppy will pick up speed once the right rear wheel has cut through the 'top' of the dune.

http://qt.exploratorium.edu/mars/opportunity/rear_hazcam/2005-06-02/1R170982747EFF55SKP1314L0M1.JPG

It is the only wheel that has yet to go over the 'ripple', which means that it has to cut through more dirt than the other five wheels and I think it slows the rover down in the process.
I hope that Oppy will be able to drag all wheels on top of the soil once it's through...

Posted by: Sunspot Jun 2 2005, 04:19 PM

We don't know how long these drives were though, they might have been more than the maximum 12m they've tried up until now.

Posted by: avkillick Jun 2 2005, 05:15 PM

<glass half full>
I think that Oppy getting stuck like this is a good thing.

From a rover engineering perpective, it has given the team plenty to consider when it
comes to the design of future rovers and the software/hardware that enables them
to traverse the martian surface unimpeded.

They have also been able to explore techniques for extracting a rover from situations like this.
</glass half full>

Posted by: dilo Jun 2 2005, 06:39 PM

Last six days movie; impressive raising of left wheel!
http://www.imageshack.us

Posted by: NoVi Jun 2 2005, 07:22 PM

<glass half full>
I think that Oppy getting stuck like this is a good thing.

From a rover engineering perpective, it has given the team plenty to consider when it
comes to the design of future rovers and the software/hardware that enables them
to traverse the martian surface unimpeded.

They have also been able to explore techniques for extracting a rover from situations like this.
</glass half full>

Posted by: dilo Jun 2 2005, 07:23 PM

And this is a PanCam detail (pseudo colors created from R1+R2 filters):
http://img230.echo.cx/my.php?image=sol482l8rg.jpg

Posted by: garybeau Jun 2 2005, 08:05 PM

Excellent picture dilo. I'm amazed at how weathered the old tracks already look as compared to the new soil that is getting churned up. It won't take 100 million years for these tracks to be gone.

Posted by: Tesheiner Jun 2 2005, 08:17 PM

Hi all,

Here is a panorama made with pancam images of the front left wheel ( sols 461-482 ), overlayed with the wheel position on each site/sol.
It is something like a "route map", but on a very small scale.

http://img96.echo.cx/my.php?image=progresssol482r1ab.jpg

Tesheiner

Posted by: Pando Jun 2 2005, 09:09 PM

Interesting how the front left wheel is starting to rise to the top of the soil. What they should do now is slow down the spin on the front wheels so that it keeps track of the rover's movement. That way it should just push the front wheels to the top, while the back wheels continue to churn away. Otherwise if the front wheels continue to spin the same rate as the back wheels, they'll just dig in again. They should be able to command the wheel movements independently I believe.

Just a thought...

Give it 2 more weeks I think and it should be out

Posted by: dot.dk Jun 3 2005, 12:48 AM

New update from the Steve!

http://athena1.cornell.edu/news/mubss/

Looks like the last two drives have been 20 meter and they saw 12 cm of progress.

Posted by: dilo Jun 3 2005, 05:00 AM

Hi all,

Here is a panorama made with pancam images of the front left wheel ( sols 461-482 ), overlayed with the wheel position on each site/sol.
It is something like a "route map", but on a very small scale.

http://img96.echo.cx/my.php?image=progresssol482r1ab.jpg

Tesheiner

Posted by: alan Jun 3 2005, 06:04 AM

They are site numbers and drive numbers from the file names
http://marsrovers.jpl.nasa.gov/gallery/edr_filename_key.html
more details in this thread
http://www.markcarey.com/cgi-bin/mt/mt-view.cgi/18/entry/25518/discussion_page?start=157&show=20