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MEX Observations Temporarily Suspended, Solid-state memory problems
Hungry4info
post Nov 2 2011, 01:20 AM
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MEX Observations Temporarily Suspended
http://www.spaceref.com/news/viewsr.rss.html?pid=38935


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stevesliva
post Nov 24 2011, 05:29 PM
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Mars Express steadily returns to routine operation
http://www.esa.int/SPECIALS/Operations/SEMYN9ZW5VG_0.html

Sounds like they expect the wonky flash to be permanently wonky.
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stevesliva
post Dec 10 2011, 12:20 AM
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More:
http://webservices.esa.int/blog/post/7/1375

Interesting.
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stevesliva
post Dec 15 2011, 07:03 PM
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Sounds like MARSIS was prime, and working again first:
http://sci.esa.int/science-e/www/object/in...fobjectid=49771

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The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express has recently completed a subsurface sounding campaign over the planet's North Pole. The campaign was interrupted by the suspension of science observations several times between August and October due to safe modes and to anomalies in the operation of the spacecraft's Solid-State Mass Memory (SSMM) system. As MARSIS best observes in the dark, which for the North Pole only occurs every few years, it was among the first instruments to resume observations once a partial work-around for the problems had been implemented.
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cndwrld
post Feb 15 2012, 09:39 AM
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MEX back to full science operations now. After a lot of work.


http://sci.esa.int/science-e/www/object/in...fobjectid=50026


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machi
post Feb 15 2012, 12:10 PM
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I have always admiration for this kind of repairing something millions of kilometers away.

And this sounds as another good news for us:

"Work is also in hand to resume operation of the Visual Monitoring Camera (VMC the 'Mars webcam')."


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stevesliva
post Feb 17 2012, 03:55 AM
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QUOTE (cndwrld @ Feb 15 2012, 05:39 AM) *


This is a great writeup, btw. Came here to link to it!

I'm still curious what causes the SSMM errors, though. A comment here:
http://www.spaceflightnow.com/news/n1202/15marsexpress/
... suggests that the memory system is having bit errors.

Though in the way ESA describes it-- "errors during the transfer of data from the MTL(in the SSMM) to the command cache"-- I wonder if the errors occur not in the memory, but somewhere in a bus between the SSMM and the command cache in the CPU. They also suggest the redundant memory controller didn't do any better.

Page 127 here has a memory system diagram for VEX, pretty much like MEX:
http://dedead.free.fr/projet/01-%20VEX.T.A...CN.00349-02.pdf

That doesn't really help show which bus could be the culprit, though, because they're basically all redundant. I suppose it could be multi-bit-errors in the flash percolating all the way through either memory controller. Except the system should catch those. So I can talk in circles and not know what's really going wrong here. And I'm curious. Anyone know of any other sources?
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