[X] My Assistant

[djellison]

Currently it's Mid Southern Hemisphere Summer - the sun is 85.5 degrees above the horizon at noon for Spirit.

100 sols from now - that figure will be 74 degrees and it will be Early Autumn
200 sols from now - 56 degrees, Mid Autumn
300 sols from now - 50 degrees, Early Winter
400 sols from now - 60 degrees, Mid Winter
500 sols from now - 81 degrees - Early Spring.

Basically it's the 150 to 450 sol's in the future period that will be the worst of it

That's all using the mars24 applet - our resident Purveyor of Whr's might be able to do a better job

Doug

Off topic posts from after 30 October moved to new thread:
http://www.unmannedspaceflight.com/index.php?showtopic=4837

Alan

[dilo]

In the last weeks, you can see again high dust levels on the sundial (perhaps comparable to pre-storm levels) and also lot of dirt/residuals on solar panels, clearly visible in Sol1355/58 self portraits!

Was the dust storm so violent to bring these smal pieces of rocks over Spirit?

[nprev]

Once again, the enormous resourcefullness of UMSF members astonishes me...go get 'em, Astro0!!!

[PaulM]

The Planetary Society MER update from 31/12/2007 includes the following statement:

The other affected instrument is the miniature thermal emission spectrometer, better known as the Mini-TES. “It sits in the belly of the rover, but looks up the Pancam mast assembly, almost like a periscope and there is a series of mirrors, folded optics [it uses],” Callas explained. “Our only meaningful theory is that there is a thick layer of dust on one or more of the optical surfaces.”

The plan to “vibrate” some of the dust off those mirrors, discussed in the November MER Update, is still on. “There's actually a mode we discovered during integration and test of the rovers more than four years ago, where you get a slight instability in the motion control -- the positive feedback hits a resonance. We've actually been able to reproduce that successfully and it doesn't propose a threat to the actuator mechanism, so we're going to try that.”

This made me wonder whether these movements would be sufficient to cause the whole of Spirit's solar panel array to vibrate. Spirit is currently tilted at 30 degrees and in my dreams these vibrations could be used to shake much of the dust from Spirit's solar panels.

[jamescanvin]

This made me wonder whether these movements would be sufficient to cause the whole of Spirit's solar panel array to vibrate. Spirit is currently tilted at 30 degrees and in my dreams these vibrations could be used to shake much of the dust from Spirit's solar panels.

No. They are just going to vibrate the mirror used to point the Mini-TES to try and shake off some dust. I don't know the mass of this mirror, but I think it's fair to say it's negligible compared to the rest of the rover. Hence there will be essentially no vibration of Spirit as a whole.

James