The Storm, Dust storm of 2007 Options

[MarsIsImportant]

I wouldn't write these rovers off just yet either. Just because they are approaching the lower temperature limit for safety does not mean we are going to lose the rover. It's possible that they will still survive intact. It's also possible that they will survive but minus some instrumentation. What parts are likely to blow? I don't know. But I doubt we would lose the whole rover.

[lyford]

I may be wrong, but the way I read that part was that the threat was being power negative, that the heaters would still come on as long as they could....

Not sure which is the bigger threat - damage from freezing or damage from battery depletion.

[Marcel]

A rover with a depleted battery can still wake up when it's electronics are still intact
A rover with a broken processor is dead.

I wonder how cold the core can get before real damage occurs. There's probably a quit large margin between the trigger temp of the heaters (-40 c) and the temp that makes silicon and conductors non functional. We're used to more examples of unbelievable durability and surprises of survival capabilities of the hardware.....

Can't sleep......

[imipak]

I wonder how cold the core can get before real damage occurs. There's probably a quit large margin between the trigger temp of the heaters (-40 c) and the temp that makes silicon and conductors non functional.

As I understand it, the problem isn't that the electronics stops working if it gets too cold - it's that thermal contraction may physically break PCB traces, soldered connections etc. (Quick edit to say - no idea what that temperature might be but presumably at design time you put the "emergency life-saver" heaters as close as you can the the lowest certified operating temperature for those systems. Of course there's no knowing how over-spec'd they may turn out to be...)

[CosmicRocker]

Yeah, thermal contraction of the physical circuits is what I thought they were concerned about.

We got another Themis 9 micron opacity map today. Although I can see some improvement in the latest image, it appears that this storm is still quite dynamic, and not obviously dying out. This is a little animation of the 3 most recent Themis maps. Opportunity is the yellow dot near the center, and Spirit is near the yellow dot on the far right side. About all most of us can do at this point is keep our fingers crossed.

[Aussie]

I believe that they had to shut down some heaters (including the Mini TES) during the first winter to stop a negative power budget caused by the defective arm joint heater . The Mini TES survived so the design must have a decent fudge factor.

[Ant103]

Hello,

To follow CosmicRocker, this is an animation who show the last month of Themis data about the storm :

(I've added Spirit and Oppy's location)

[nprev]

Beautiful work, Ant...clearly illustrates that Oppy got it first & worst.


(OT here, but it appears that we have a bit of a Matt Groening-inspired avatar party going on this thread!)

[Zeke4ther]

Another update on Opportunity here . Things may be getting a little worse.
Keep you fingers crossed

[elakdawalla]

That's just a repost of yesterday's press release.

--Emily

[Zeke4ther]

I thought it read kind of like a re-hash . But it seemed to have some new stuff....Oh well.
Your Blog is at The Planetary Society is way more interesting and informative.

Thanks Emily.

[fredk]

New sol 1250 Oppy pancams up on exploratorium. I guess this means that today's expected communication session was a success, and Oppy hasn't yet dropped into low power fault mode. I wonder what the array levels are...

[imipak]

Re-reading this quote from John Callas on the fine Planetary Society blog (which I was not checking daily until reading this thread, despite being a member -- an omission I have now corrected) I had a small & rare positive thought:


"...If there is not sufficient energy, Opportunity will stay asleep. Depending on the weather conditions, Opportunity could stay asleep for days, weeks or even months, all the while trying to charge her batteries with whatever available sunlight there might be."

( http://www.planetary.org/blog/article/00001055/ )

So I'm thinking ahead, say, 40 Sols. Suppose the worst happens -- the heaters trip, the batteries discharge and boom, it's lights out, goodnight Vienna, right? Ah but wait... suppose the panels are covered by a thin layer of dust fallout. As luck would have it, this gets puffed off by a passing not-a-dust-devil... the batteries begin to trickle charge once more and a few days later (as the old sailor's song goes...) "Wa-hey, up she rises"

So the question is, how long do you carry on looking for a signal? More to the point, how long do the actual JPL team carry on looking for a signal? Actually, that now starts to look like a rather less positive scenario - Oppy clings to life, bravely recovers, calls home - and is ignored...




[quick edit: argh-confounded-pseudo-tags!]

[djellison]

I think Pathfinder is a good basis on which to guestimate that... several weeks of daily efforts. Then a few weeks of less-regular efforts, and then a occasional, perhaps once a week, efforts for a couple of months.

Doug

[Stu]

several weeks of daily efforts. Then a few weeks of less-regular efforts, and then a occasional, perhaps once a week, efforts for a couple of months.

Oh no no no no no no no.... I couldn't go through those dark "Earth to Beagle, Beagle come in please..." days again...

(This topic gets the award for 'Most Depressing For A Long Time" I reckon...)