Extricating Spirit, Digging out from Troy Options

[alan]

The regional dust storm that started around sol 2000 dropped the dust factor (the percentage of sunlight reaching the solar panels) from 0.844 to 0.614 over the period of about a month.

[Hungry4info]

Oww, okay. Thanks for the info.

[marsbug]

http://science.nasa.gov/headlines/y2009/02...y.htm?list15891
I know this is old news, but I just made the connection between sulfates coming from vent activity and the crater's edge Spirit is sitting on. What are the chances the crater is an ancient vent? Or is the sulfate a layer in the hill that the crater happened to punch into? Could the RAT gum its way through the duricrust? (haha, just had a thought of adding a small aircannon or railgun on future rovers to punch through duricrust with BB's at range in "danger areas". That could go along with the laser on MSL! )

Is Dburt still about? I'd think he would have a comment or two.

[dburt]

Is Dburt still about? I'd think he would have a comment or two.

You rang? At this point I'll just guess that the tiny crater in question, like Home Plate itself, is unlikely to be a local volcanic vent, because local vents generate nearby coarse ejecta, and repeat myself that all of the bedrock at and near Home Plate appears to be continuously layered, with bedding lying sometimes at surprisingly steep angles. Sulfate concentrations vary in a mysterious manner that suggests some kind of complex post-depositional redistribution mechanism, perhaps involving surface moisture, freeze/thaw, evaporation/sublimation, and wind (hope that's vague-sounding enough ).

---HDP Don

[hendric]

I was thinking more along the lines of a fumarole than an actual lava-spewing vent. That would explain the high concentration of sulfur inside the vent. The material inside might still be windblown dust, just picking up sulfur from deeper in the fumarole stack. Not implying it is active either, just a source of sulfur that can be moved upwards towards the surface via chemical reactions or minute water traces.

[marsbug]

Thats nice and vague thanks! If it's a meteorite crater might the presence of the sulfates in the crater tell us something about the redistribution mechanism? If the sulfates and the crater are related, and its not just a coincidence that one is in the other, then without knowing how else the sulfates might have got there the idea of fumerole seems (to my very limited geology knowledge) to fit. Mods I won't ask any more questions on this subject after this post, I've no wish to derail the thread.

[djellison]

HDP has his own very lengthy thread for his ideas based on the MER results - discussion should be in there.

[fredk]

In the latest Spirit update there are details on how the 2104/05 RR wheel diagnostics went.

The rover team cannot draw any conclusions at this point, but the results are not encouraging, and further tests are planned.

[nprev]

I'd guess they're probably gonna try to run the wheel in the opposite direction a bit to see if it rotates at all, of course, and also to try to dislodge any foreign object that might be stuck in there.

[PDP8E]

Hey nprev,
Burning out a wheel actuator that is buried (see animations) ... and who knows what is clanking around in that wheel cavity... may force a prophylactic shut down of that wheel (RR). This may force a crab walk towards home plate to get the left front wheel on solid ground, that sets up a slogging pull out of Scamander. After all that, a full evaluation of the RR could then be done at leisure ... after the rocks fall out!
But with my minor speculations aside, I hope the JPL team will deliver a mobile rover in the weeks to come after their combined hard work.
Cheers

[fredk]

Back to the present... I'm still seeing what appear to be new dust devil tracks forming out there. Here's an example that appeared between sols 2099 and 2104. The endpoints of the track are marked with the white arrows:

The lighting angle is almost identical between these two frames, so it is a real albedo effect.

Presumably this means is that there's still a glimmer of hope that we'll see some strong gusts at Spirit that clean the panels.

[marsophile]

The lighting angle is almost identical between these two frames, so it is a real albedo effect.

Or could it be a localized darkening due to the shadow of a cloud in the sky?

[fredk]

There were two F hazcam frames on sol 2104 taken almost 40 minutes apart, and there's no movement in the dark streak between them that I can see. Also frames were taken on sol 2105 and it looks like the streak is still there, although the lighting is quite different.

[fredk]

From a New Scientist story:

A rock stuck in the wheel seems unlikely at this point, since previous jams have not prevented the wheel motor from moving altogether, as was observed in this case, Callas says.

[MahFL]

The latest blog entry on the Free Spirit website is Dec 12.....someone invented a time machine ?.....it's the 9th Dec as I type this.....