The silica sand so close to the surface already tells that the rate of removal has been greater than the rate of deposition. It's a bit amazing that there isn't actually any patch exposed.

Is the white substance sand (ground down rock) or is it some other type of deposit?

Why might it be that the silica deposits [Edit - or other light-toned material], once covered by the same fine wind-blown dust as is accumulating on Spirit, isn't randomly exposed by, e.g., dust devils?

Or perhaps Mars' high UV flux quickly discolours (colours?!) the white material when it becomes exposed at the surface.

They have analyzed the red and white materials several times and know the compositions. There is no question of discoloration. They are different materials -- and not because of UV flux.

Hi Centsworth,

I think Stephen was trying to say not that the various hues in the lighter toned materials were due to UV exposure, but rather that prolonged UV exposure possibly 'degraded' the lighter toned material into one that was at least less visually obvious (darker and closer to the local surface soil color).

I might be wrong in my reading of Stephen's question. If so, it is at least a question I had wondered myself. I had held off posting for now as I had not done the forum research that I thought worthy before asking -- my memory seems to recall a discussion on this very question a few years ago, possibly when spirit was somewhere between LRH and returning to the eastern side of HP.

So, with more words written than intended, I'll be quiet and sniff around some more before I hopefully post again.



-- Pertinax

Trying a new tactic?


sol 1892

Click to view attachment

sol 1893

Click to view attachment

It is curious that such a starkly white material would be so close to the surface and yet not be seen, so far, anywhere on the surface. Perhaps there is some version of the Brazil Nut Effect at work. I really don't know enough to comment too much about it myself.

Perhaps there's a bit of a "crust" that forms in the dark soil topping and in contact with the white deposits, due perhaps to some interaction between the two. Perhaps UV from the Sun is involved when the white deposits are very shallow. Perhaps the crust is sufficient to prevent gusts/dds from exposing the white deposits. Or perhaps there's a sufficient "crust" everywhere near the surface, just below some loose dust, due again to UV from the Sun.

A lot of "perhaps's"!

Perhaps the top few cm everywhere are effectively mixed by wind action. There everything should be sorted only by size and density of the particles. If the white particles are similar to the rest of the soil in these respects the wind would homogenise the mixture. Perhaps there is a tiny fraction of the white grains everywhere among the surface stuff.

http://twitter.com/marsroverdriver

"Word on the street is that Spirit's energy level is up again -- 392 W-hr today. Is 400+ in her future? That would be a sight for sore eyes!"

Great news again!

Great news, indeed! She's trying to beat her sister.

My impression is that this place has a sort of "funnel" effect, as already noted by climber. Perhaps we should stay here for a week, meanwhile taking more pictures of the layering at HP and waiting for another cleaning event... or two.

Given the recent rate of advance, that's probably what will happen anyway.

Looks like there was some progress on sol 1894.

I can't see (yet) the downlinked data from sol 1894 but the images on the GIF represent the move between sols 1889 and 1891. On sols 1892 and 1893 there were no net advance AFAIK but only the wheels moving inward.

Edited: Another 10cm during sol 1894.

Ah, you're right. Not sure why I thought that last frame was from 1894. Must be going mad.

No, no, you're right! Tosol position is similar to sol 1889 and your last frame IS from sol 1894. My bad.

Maybe we've contracted Spirit's amnesia!

A question: how are your these raw images of spirit? (these raw images are not online by Exploratorium or JPL)
(sorry for my english)

This animation was made from thumbnail images that can be retreived by using the MER Pancam Data Tracking Web Interface

thank you

I've removed the direct link above. The database is currently down, giving the error "Not connected to database Too many connections". If you need the database (and you probably don't), you can Google for it.

Sorry. I was wondering whether I should give a link or not before I replied so I checked back through the forum history and found it had already been posted many many times. I guess the readership of UMSF has climbed a bit in recent years! Also, entering 'pancam' into google gives the Cornell pancam website (with the database linked on the front page) as the first result.

That was a (failed) attempt to turning in place. No change in position, microscopic change in heading.

Paolo

The exploratorium is down once again and, like in the previous case, it only affects Spirit's images...

maybe the server is protesting being kicked too many times

Yesterday was driving sol and according to the data I have Spirit barely moved itself. Just a few cms, perhaps.
Today's plan (sol 1898) includes driving too but the imaging pattern is one which is usually used while attempting extract a stuck rover.

01898::p1214::05::2::0::0::2::0::4::front_hazcam_ultimate_4_bpp
01898::p1244::00::2::2::0::0::0::4::front_hazcam_wheel_sub_256x256_4_bpp_pri_16
01898::p1244::00::2::2::0::0::0::4::front_hazcam_wheel_sub_256x256_4_bpp_pri_16
01898::p1244::00::2::2::0::0::0::4::front_hazcam_wheel_sub_256x256_4_bpp_pri_16
01898::p1244::00::2::2::0::0::0::4::front_hazcam_wheel_sub_256x256_4_bpp_pri_16
01898::p1244::00::2::2::0::0::0::4::front_hazcam_wheel_sub_256x256_4_bpp_pri_16
01898::p1244::00::2::2::0::0::0::4::front_hazcam_wheel_sub_256x256_4_bpp_pri_16
...

BTW, still no image update @ exploratorium.

I guess it's probably a bad thing when you can't see the wheels

http://qt.exploratorium.edu/mars/spirit/re...DJP1314R0M1.JPG

The rear left is visible, if a little caked in dust.

the rear right is pulling some big deflection on the right rocker though - I think it's gone low, so the right middle wheel could well be off the surface. That would give us a situation a bit like Tartarus - where we were down to like, 3 wheel drive.

Incidentally, the Exploratorium is now flushing through - and has out-done itself, with 5 hrs from image taking to being posted. That's the best for quite a while.

a -little- ?

you're right tho, it is there and easy to see here because of the light on the treads

http://qt.exploratorium.edu/mars/spirit/re...D7P1344R0M1.JPG

so this front haz cam is showing that the only wheel we have on good soil...is the one that doesn't work?

http://qt.exploratorium.edu/mars/spirit/fo...DJP1214R0M1.JPG

do we think that's just a coincidence or have we broken through and dug in with the turning wheels while the immobile wheel is sitting on a crust?

by way of revision - I dug out my rover suspension animation.

http://dougellison.com/dougstuff/rov_susp.mov

This is roughly accurate to demonstrate the range of movements available to the rover - but of course, it has limits on this angles that will stop driving if the vehicle is in danger of self contact.

I knew it, Spirit is doomed. This is worse than Purgatory and Tartarus put together. They can't possibly get her out of this.

Shush, don't argue, just let my unfailing ability to be wrong work its magic.

Nice one
http://qt.exploratorium.edu/mars/spirit/na...CNP0783R0M1.JPG

some new images, the only motion I can detect clicking between images is down
http://qt.exploratorium.edu/mars/spirit/re...DNP1354L0M1.JPG

Lot of material in the wheel wells, I wonder if this is having an effect on the temperature and the currents in the actuators.

Apparently there was a lot of motion ... of dust off deck. Spirit seems to have had another, big cleaning event. We may see some fun energy numbers after a full sol or two go by.

Scott just Twittered that Spirit's levels are up to 470 W-hr...

Now we've got avoiding putting back some dust on the solar panels while getting out of the sand trap.
Anyway, the more energy, the more chances to get free, and ~500W-hr is a LOT of energy

Are Spirit's solar panels now clean enough to provide power through the next Winter without changing their orientation? If so then Spirit might survive the next Winter, even if it is stuck.

I am still hopeful that Spirit will continue to move in some direction. Also the standard 50-60 day stop when rovers get really stuck always produces a great 360 degree panorama.

470 Whr! Incredible. Getting stuck here has been something of a blessing in disguise.

As a basis for comparison, does anyone know what Spirit's Whr's were at an equivalent point in the last martian year? What are we now, about 2 weeks before the solstice?

Oooo - no - we're not close yet. Spirit had > 800 Whrs last summer...and JUST, JUST made it through on a perfect slope.

Looking at the FL wheel it barely moved if you look at the visible wheel cleat on it. At least I hope it barely moved because it would be bad news if it did several turns

Those high power levels last summer were after cleaning events just before the big dust storm. After the storm, her power levels were stuck down in the mid 300's at best. Presumably the storm kicked up lots of dust which settled after the storm, negating most of the power gains just before the storm. That's why they just made it this past winter on a very steep slope. The previous winter, at Low Ridge Haven, she didn't have as much dust going into winter, so she got by easily on less of a slope.

So if we don't get a big storm this winter, and continue to get cleanings, we may not need a very steep slope to overwinter.

That's the big IF.
Heck, start the winter at 400 plus rather than 300 and getting through this coming winter could be a breeze.
Click to view attachment

470whr/sol is pretty damn fine but it's a long way from a safe buffer for next winter. Still I'm not complaining - here's hoping it gives the drivers enough juice to extricate her from where she is and make some more progress.

470 - great news.

I thought it likely that long term electrostatic/chemical/sunlight effects might have produced a more bonded layer of dust (talc) that the thin Martian air wouldn't have been able to blow away even in high wind gusts.

Great to have been proved wrong!!!!!!

Well you are leaving out the part about the dust storm and the subsequent dustfall from it that brought the power way down prior to the onset of winter.

She's overtaken Oppy! From the latest update:

Great news about the power levels!!!
And it's a good way to start sol 1900.
Click to view attachment

Yeeha! That's a much needed boost.

Can't this rover rotate CCW or otherwise around it's lame leg?

It could...but the other 5 wheels don't have good traction at the moment