New hazcams up!!

http://qt.exploratorium.edu:16080/mars/opp...E3P1214L0M1.JPG

http://qt.exploratorium.edu:16080/mars/opp...E3P1314R0M1.JPG

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

Some gifs

Left


Right


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

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....

Looks very encouraging at the back

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.

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

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.

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.

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

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.

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.

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

No one looked to "front" right wheel, probably because pictures are extremely dark... (maybe due to luminous reflection from the metallic arm in the low/right ); after managing luminosity/contrast and removing jpeg artifacts, quality still poor compared to other animations but interesting in contents:

It appear that very small horizontal movement was made, and momentanous rising up was followed by a down escavation; this is exactly the reversed behaviour of the opposite back-left wheel, which clearly lifted up.
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... :
[
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, as confirmed by following composition of two front HazCam (red channel = Sol 461, Blue = Sol 436, notice horizon difference):

Hmmm - I think I found Oppy's new autonav routines. Now I finally have the skills needed to be a rover driver!

Thanks for the animations, dot.dk and dilo!

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

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

Hi Marco, I think the up or down movement of the wheels isn't directly correlated, because of the Rocker-Bogie suspension system. My guess is that each wheel have to drive back in different deep tracks due to the angle that Oppy has driven up on this dune. Probably the right rear wheel (the real in normal forward drive direction) is less charged than the left.

According to the latest description I've seen of the planned back-out maneuver, they're supposed to be moving back *not* in a straight line, but in a leftward arc (leaving the stuck front wheel at its seven-degree toe-in position). It would make sense, then, that the left side would move a little more than the right.

Remember, according to the plan, they're only going to spin the wheels a few meters' worth each day and see what happens. They think it'll take days, if not a week or more, for Oppy to actually back out.

In other words, don't panic -- the maneuver isn't supposed to have gotten us very far yet.

-the other Doug

I don't know -- the dune we got stuck in is only about 30cm tall, after all. Not tall enough for Oppy to bottom out or anything.

From what I read of the analysis of Oppy getting stuck in the first place, they thought that the problem was not that Oppy ran into a dune that was too soft to support it -- it was that we got into a position where the three wheels on one side were on one side of the dune crest, and the other three wheels were on the other side of the dune crest. They didn't see any real compositional or textural differences between the dunes Oppy had climbed over with no problem and the one they got stuck in, except for the positioning of the wheels astride the crest.

I'm not an engineer, but I can "feel" how the rocker-bogey system would suddenly be less effective if the slopes suddenly sloped away from the vehicle on both sides.

In other words, it's possible that all we have to do is avoid driving over dunes at a shallow angle to their crests. I bet we'll be able to cross the dunes easily as long as we approach them transverse to their crests...

-the other Doug

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"

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.

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?

It was a blind drive, and I assume that any checks that the rover can make did not involve "digging in". It's a safe bet they'll be adding that to the repetoire if they can.

...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.

I imagine that "forward" direction is referred to original Rover orientation, so in fact is backward referred to actual moving direction (which is my preferred convention, in order to answer to Edward Schmitz )...
Anyway, they confirm slight downward movement, but "results were a good match for what was expected from tests on Earth"... so let's wait for "second act"!

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.

Whoa...well spotted
I wouldn't have thought it could have either. Espeicially considering they only did 2.5 revolutions over...what.....about an hour an a half or so??

Edit: An hour and 13 mins. Thanks CosmicRocker

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.

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

I don't think it's caused by vibration:
(GIF-quality-reduced-file) http://www.greuti.ch/oppy/oppy_sol463_navcam.gif

I only can see one local change in the track and additional a change of shadow. If it's caused by vibration there must be more, isn't it?

The difficulties in getting the Apollo deep cores out of the ground had nothing to do with temperature. On Apollo 15, the extreme difficulty (both in drilling down and pulling the core back out) had to do with a design problem with the drill stems and the extraction equipment, as well as the tendency for lunar soil to become highly compacted just a few millimeters below the surface.

I don't think there is a really "hard" surface under Oppy's wheels as they're stuck in the drift. I just think that's as deep as the wheels go in with this consistency of powder, the wheel design, the weight of the rover, etc.

Remember, there's nothing in the way of liquid water left in this dust, so "freezing" it shouldn't have any gross effects. And the temps during the day on Mars are also generally below freezing, so the temps are overall too cold for us to see any "change of state" difference -- based on water, anyway. And none of the other atmospheric components or soil components would change state readily over the temperature ranges at Meridiani.

-the other Doug

Very good finding, Ed...
The two full res images, taken before and after movement, clearly show the collapsed material (enhanced version):

I carefully compared the two rover tracks in both left/right NavCam (crossed eyes technique is very efficient dooing this ) but didn't find any other appreciable difference, apart shadow changes due to different time...
Based on this, I'm convinced that vibrations causing this collapse cannot be transmitted by small movements inside caothic material inside tracks, but must be due to some underlyng rigid material... this is an indirect confirm that there is an hard layer under the sand and this should be good for Oppy!
Very interesting considerations about night/cold movement, but I thing should be left as last option because it would be impossible to control the effect for navigation software...

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.

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 :

Is this what we are seeing

"Viking Lander and Pathfinder observations showed that the soils at these three Mars landing sites are diverse, with surface deposits of aeolian dust, drifts and dunes, and an underlying indurated deposit that has been called duricrust. Viking Lander observations [Clark et al., 1982] showed that duricrust contains more sulfur and chlorine than loose surface deposits. Many researchers believe that duricrust formed when thin films of water migrated from the subsurface to the surface, evaporated, and left behind salts. Others believe that the duricrust formed as sulfur and chlorine rich volcanic aerosols settled onto the surface under relatively moist conditions that would allow cementation to occur. The origin of duricrust remains uncertain, although the correlation with volatile species and
probable association with water remain key elements of extant hypotheses."

From http://europa.la.asu.edu/pgg/greeley/cours...quyres_2003.pdf

Pg. 24


Gary

Have we made a significant move?

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

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

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

It may be, but likely Oppy got stuck in a drift that has an area of "light and fluffy" windblown material, likely Mg-sulfate from the evaporites. The firmer material underneath may be the usual blueberry crust we've been driving on.

She did move, and at this point, any movement is significant...

--Bill

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.

Those anims are SUPERB Gary - nicely done

Doug

She's a' movin' !

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

Glenn

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

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 ?

I don't think the 2½ wheel turn was done continuously. They turn a bit, take a picture, turn a bit again, take another picture etc.

All these small turns and taking pictures does take som time apparantly.

Thanks to Garybeau, it was still "little" work to do:

http://www.greuti.ch/oppy/Oppy_sol465_front_left.gif

It shows the left front wheel and the Mars time just after the respective rotation. I got the time from the amazing MidnightMarsBrowser. Oppy has always shoot first the left front wheel, then the right front, right rear and left rear wheel (this last wheel circa 2 minutes later as the first).

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

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

I made some "pseudo" color images starting from these front wheels PanCam taken on Sol 463 and 465 (upper part is L2+L7, lower is R1+R2):

The answer to your question is that only front/right wheel (top frames) moved significantly.
This obviously produced further counter-clockwise rotation of the rover, as showed in the new NavCam sequence below:

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