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

Some dust settling though as mentioned above

That looks like the auto nav software trying to find a good path.

But I did see other images that made me think that it might have gotten in and out of trouble on its own. We know that happened durning egress from eagle crater. They made a blind drive toward the crater rim, but didn't make it. It slipped and dug in. REALY DEEP. Still in blind drive mode it made a ninty degree turn and drove away.

All the other images were too far back to see what happened.

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

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

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

Scott

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.

It was really funny to see the speed up part of this movie when the rover drove into the dune
http://www.exn.ca/news/video/exn2005/05/09...09-sandtrap.asx

Imagine if that were the normal pace

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

Dependent on the material of course, and I suppose that if it were really fluffy (which this stuff may be), you could pound it down even more -- but I think the problem we saw with initially getting stuck had to do with digging more than compressing. And the compressing has limits. Hmmmm...

Depending on the soils, some digging at the ends of the hole (on the created ramps) may be advantageous as long as it results in some linear motion of the rover, and doesn't dig much deeper than the vertical progress that has already been made.

Even with low speed motion, as long as you can get some motion forward, followed by some motion back, you should be able to continually elongate the hole.

Somebody ought to do some research and write a paper on rocking motions to get out of loose materials with different particle sizes etc. Fun stuff. Seems like this "art" known only to hard core 4x4 drivers could be reduced to something resembling a science.

Scott

The wheels have been straightened

http://qt.exploratorium.edu/mars/opportuni...DJP1214L0M1.JPG

http://qt.exploratorium.edu/mars/opportuni...DJP1314L0M1.JPG

Pedal to the metal

seriously know, what is the next step? move forward a little bit?

Look at these two Pancam pictures

http://qt.exploratorium.edu/mars/opportuni...DIP2131R1M1.JPG

http://qt.exploratorium.edu/mars/opportuni...DJP2131R1M1.JPG

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

To me the bottom of that trough looks pretty firm

The sides of the trough also look surprising firm (and vertical) in the second pic, too, as if they had been sliced with a knife, with no sign of sand or dust falling back in that seemed to be suggested in the first pic.

(Actually, when I look back at pics like this rear hazcam one:

http://marsrovers.nasa.gov/gallery/all/1/r...DIP1314R0M1.JPG

from the look of that wheel on the right there hasn't been much sign of infilling there either.)

Would that be the action of the wheel compacting the sides which did that or a characteristic of the dune material itself?

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

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: