Spirit cleaner? |
Spirit cleaner? |
Jun 18 2007, 06:44 AM
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#1
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Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
I've been keeping an eye on the sundial images looking for signs of a cleaning event. I've noticed some changes in the latest to be downloaded although they may be due to changes in the lighting.
A : clean patch at top of circle streak at bottom B : increased contrast from dust left behind next to mirror C : clean patch next to wire Also note the missing clumps of dust on the deck A broader view show a contrast between sol 1221 and 1227 http://207.7.139.5/mars/spirit/navcam/2007...I4P0165L0M1.JPG http://207.7.139.5/mars/spirit/navcam/2007...00P1914L0M1.JPG Has anyone heard if there has been a change in the power levels? |
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Jun 28 2007, 11:34 AM
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
738 Whr means she is still losing about 25% due to dust. Last summer at peak when she was generating 956 Whr the dust loss factor was around 5%. So she's getting cleaner but I don't think that surviving the winter is guaranteed yet. She bottomed out at 280Whr in mid winter at Low Ridge so right now we'd be looking at around 220Whr for the minimum next winter assuming nothing else changes (and dust deposition follows last years pattern).
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Jun 28 2007, 04:01 PM
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#3
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Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
738 Whr means she is still losing about 25% due to dust. Last summer at peak when she was generating 956 Whr the dust loss factor was around 5%. So she's getting cleaner but I don't think that surviving the winter is guaranteed yet. She bottomed out at 280Whr in mid winter at Low Ridge so right now we'd be looking at around 220Whr for the minimum next winter assuming nothing else changes (and dust deposition follows last years pattern). Remember, too, that we're not just talking about a pretty straight-line graph in which the amount of dust entrained in the atmosphere relates directly to the amount of dust deposited on any given surface. There are a lot of microclimatological effects right along the surface that greatly impact dust deposition rates. If we were to park Spirit on top of El Dorado for a winter, for example (and I know, it would never happen, it faces the wrong way, etc.), you'd likely never survive because the hills force a turbulence that drops dust out of the air selectively onto the El Dorado formation. IMHO, Spirit spent last winter in a place that tends to collect a little more dust than other places within reach. If she can claw her way up the side of a hill that faces into the prevailing winter winds, as opposed to sitting in a "deposition sink," she might have a better shot at surviving her next winter. But if she stays exclusively in the Home Plate area and doesn't get very far from it, the deposition rate may be just high enough to kill her without an extraordinarily vigorous cleaning event just before the onset of winter. -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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