Expected operational life of Spirit

I've googled and googled and I can't find any info on the expected operational life of Spirt and Opportunity. Pathfinder went about 90
days. Is that what we can expect for S&O, or have they been "hardened"?
And what will kill them anyway? They are solar driven right? Couldn't they go on until the gears wear down (or something)?
tia, Mike
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The NASA site says they're good for 90 days. They die when they run out of power. They run out of power because of the increasing distance of mars from the sun, dust on the solar panels, batteries losing capacity, and seasonal changes on mars also decreasing solar availability.
Tim
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"wind shield wiper" style brush should have been installed, but why not? Can't afforded? Also, how sticky is dust to the solar panel in zero humidity environment? My guess is that a wind breeze in the right direction/angle will just blow the dust away. Does NASA know which way the wind blows on Mars?

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It is my understanding that dust is amazingly sticky due to static cling. I thought they had a heater system in it to help keep the batteries and electronics to some minimum temperature. When power levels drop to a certain point then the heater fails, and the rest of the system shortly after that. Batteries and elecronics don't work all that good at 100 below zero or so.

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Can you believe what they tell the public? If I was in command I do the holliwood production for the public and then get down to some serious science. Any gold miners out there?
Tom
MikeWise ( snipped-for-privacy@gmx.net) wrote: : I've googled and googled and I can't find any info on the expected : operational life of Spirt and Opportunity. Pathfinder went about 90 : days. Is that what we can expect for S&O, or have they been : "hardened"?
: And what will kill them anyway? They are solar driven right? Couldn't : they go on until the gears wear down (or something)?
: tia, Mike
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