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Dust Storm
marsophile
post Oct 7 2018, 12:17 AM
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Although there was an excellent detailed description of the recovery efforts in the MER report, there are a few things that are unclear to me.

What is the "checkmate" condition, exactly? Can someone explain this a little more?

Also, hypothetically, if the solar panels were clean but the battery was impaired, could Opportunity communicate on solar power alone, without current from the battery? I realize that might mean a continuing clock fault, which would probably make timing too awkward to continue the mission very long, but it would still be worthwhile to learn the state of the rover following the dust storm.
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djellison
post Oct 7 2018, 12:37 AM
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Checkmate scenarios are where the vehicles is getting 1.2A on the arrays - so it's 'solar groovy' - but for a duration that means - combined with the fault protection timing - it never actually opens up a fault window. It's pretty likely for short solar groovy periods- and then increasingly unlikely as the solar groovy duration gets longer with cleaning.
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Sean
post Oct 7 2018, 03:57 PM
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I'm using 'solar groovy' in every Oppy discussion from now on.


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marsophile
post Oct 8 2018, 12:40 AM
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If it's time for some levity, maybe in the future Mars helicopters can fly over ground rovers, and blow off the dust!
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James Sorenson
post Oct 8 2018, 02:39 AM
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The Columbia Hills (Spirits location) is one of the landing site candidates for Mars2020 and the Helicopter. wink.gif
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Explorer1
post Oct 8 2018, 03:43 AM
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QUOTE (James Sorenson @ Oct 7 2018, 09:39 PM) *
The Columbia Hills (Spirits location) is one of the landing site candidates for Mars2020 and the Helicopter. wink.gif


Now that would be a comeback story! Spirit doing her best impression of Rip van Winkle.... laugh.gif
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bugs_
post Oct 8 2018, 05:18 PM
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QUOTE (James Sorenson @ Oct 8 2018, 02:39 AM) *
The Columbia Hills (Spirits location) is one of the landing site candidates for Mars2020 and the Helicopter. wink.gif

Now that sounds extremely solar groovy!
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fredk
post Oct 8 2018, 06:12 PM
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QUOTE (mcaplinger @ Oct 5 2018, 04:21 AM) *
The fact of the matter is that not much can be determined from the HiRISE image, but clearly people want to believe that the rover is very dusty, since that's an explanation for why it hasn't woken up yet.

At least there is a bit more that can be done. From the September report:
QUOTE
In coming weeks, MRO will be gathering more data with CRISM, HiRiSE and the CTX. “We’re planning on making observations over next several months to monitor the surface changes over Endeavour as the storm subsides,” said Arvidson.

With CRISM, which is a little better calibrated and a little more sensitive to dust cover, they may be able to get a better idea of how much dust there might be on the ground. “It would be a way of trying to estimate whether the dust on the arrays is high, medium or low,” said Zurek. “We’re trying things. We’re going to try with CRISM. We don’t know if we can get something out of that, but it’s worth a try and we’re going to give it a try.”

“Obviously we’re not going to be able to resolve the rover in CRISM data, but it could give us a better handle on what’s going on with the dust environment,” Squyres agreed.
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marsophile
post Oct 10 2018, 02:20 AM
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QUOTE
“It has been suggested that we are commanding just a little too late in the day, that we should be commanding earlier in the sol,” said Nelson. “And there is some rationale for that.”

Therefore, the mission is now trying to move some of their dish time earlier and/or negotiate their timeslot to pick up the Martian mornings at Endeavour. “We’re trying to widen our pattern,” Lever said. “We figure that we’re on a nice easterly tilt and when the Sun comes up, chances are we could get a solar array wake up in the morning instead of at noon.

Indeed, if the rover is tilted 30 eastward, then a morning sun elevation of 60 degrees might optimally match that tilt. I think that might occur at around 10 am local time. Perhaps that is the most "solar groovy" time. laugh.gif
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RoverDriver
post Oct 10 2018, 02:19 PM
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QUOTE (marsophile @ Oct 9 2018, 07:20 PM) *
Indeed, if the rover is tilted 30 eastward, ...


Not sure if this is a typo, but it could be I misled someone in thinking so with a post made some time ago. When I said the attitude *difference* between two positions was 30 degrees it was due to the fact the rover in the first position was at about 10 deg Westerly tilt, and now it is at 20 deg Easterly. So the current rover Easterly is (only) 20 deg. Still the point being made about the SAW is correct.

Paolo


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Gerald
post Oct 10 2018, 10:04 PM
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QUOTE (fredk @ Oct 8 2018, 08:12 PM) *
At least there is a bit more that can be done....

Would additional HiRISE images reveal tracks of dust devils or gusts, maybe on the basis of appropriately adjusted difference images? If so, this should return a hint of when the dust load on the arrays should have changed, i.e. cleaning events may have taken place. These gusts are probably larger than the rover, and their tracks would be easier to resolve.
Another approach would be the inference of an SR image from several HiRISE images, provided the size of the pixels is the limiting factor for the resolution. Alternatively, S/N could be improved by averaging a sequence of well-registered HiRISE images.
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serpens
post Oct 11 2018, 02:31 AM
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Perhaps the best indication of dust clearing, or a dust cleaning event will be communication from Opportunity.
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