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Curiosity and other rovers issues with flash memory



 
 
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  #1  
Old March 14th 13, 09:00 AM posted to sci.space.station
Brian Gaff
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Posts: 2,312
Default Curiosity and other rovers issues with flash memory

Considering that flash memory is not knew, and is I understand used
extensively in the new capsule for humans and probably on the iss but I
don't know that for sure, they do seem to be having a lot of issues with it
corrupting. One assumes this is due to radiation, but it could also be due
to some inherent instability caused by read/writes or temperatures
experienced. Its interesting to see it happening already to the latest
rover while its only just started to happen ont the older rover.
I do hope someone is looking into this problem as its not a problem you
really want if your crew is many days or months away from earth in some
critical system.
Brian

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  #2  
Old March 15th 13, 11:22 PM posted to sci.space.station
Jochem Huhmann
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Posts: 606
Default Curiosity and other rovers issues with flash memory

"Brian Gaff" writes:

Considering that flash memory is not knew, and is I understand used
extensively in the new capsule for humans and probably on the iss but I
don't know that for sure, they do seem to be having a lot of issues with it
corrupting. One assumes this is due to radiation, but it could also be due
to some inherent instability caused by read/writes or temperatures
experienced. Its interesting to see it happening already to the latest
rover while its only just started to happen ont the older rover.
I do hope someone is looking into this problem as its not a problem you
really want if your crew is many days or months away from earth in some
critical system.


I'm fairly sure that this is just one of the problems you have to deal
with by redundancy and backups. You can't expect to have no memory
corruption (or outright failure) at all, even under the best
circumstances. **** happens, everywhere and always, even in space.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery
  #3  
Old March 16th 13, 09:42 AM posted to sci.space.station
Brian Gaff
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Posts: 2,312
Default Curiosity and other rovers issues with flash memory

That is true, but one would imagine that memory protection is rather a vital
thing to have issues with, considering the number of years its been on
spacecraft. back in the old days they actually used to fly tape recorders as
I recall.These tended to stick in the varying temperatures out there.
Brian

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From the Sofa of Brian Gaff Reply address is active
"Jochem Huhmann" wrote in message
...
"Brian Gaff" writes:

Considering that flash memory is not knew, and is I understand used
extensively in the new capsule for humans and probably on the iss but I
don't know that for sure, they do seem to be having a lot of issues with
it
corrupting. One assumes this is due to radiation, but it could also be
due
to some inherent instability caused by read/writes or temperatures
experienced. Its interesting to see it happening already to the latest
rover while its only just started to happen ont the older rover.
I do hope someone is looking into this problem as its not a problem you
really want if your crew is many days or months away from earth in some
critical system.


I'm fairly sure that this is just one of the problems you have to deal
with by redundancy and backups. You can't expect to have no memory
corruption (or outright failure) at all, even under the best
circumstances. **** happens, everywhere and always, even in space.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take
away."
- Antoine de Saint-Exupery



  #4  
Old March 18th 13, 05:38 AM posted to sci.space.station
snidely
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Posts: 1,303
Default Curiosity and other rovers issues with flash memory

"Jochem Huhmann" wrote in message
"Brian Gaff" writes:

Considering that flash memory is not knew, and is I understand used
extensively in the new capsule for humans and probably on the iss but I
don't know that for sure, they do seem to be having a lot of issues with
it
corrupting. One assumes this is due to radiation, but it could also be
due
to some inherent instability caused by read/writes or temperatures
experienced. Its interesting to see it happening already to the latest
rover while its only just started to happen ont the older rover.
I do hope someone is looking into this problem as its not a problem you
really want if your crew is many days or months away from earth in some
critical system.


I'm fairly sure that this is just one of the problems you have to deal
with by redundancy and backups. You can't expect to have no memory
corruption (or outright failure) at all, even under the best
circumstances. **** happens, everywhere and always, even in space.

On Saturday, Brian Gaff queried:

That is true, but one would imagine that memory protection is rather a vital
thing to have issues with, considering the number of years its been on
spacecraft. back in the old days they actually used to fly tape recorders as
I recall.These tended to stick in the varying temperatures out there.
Brian


The type of Flash memory is also important. NOR-based Flash tends to
be more stable, but costs more. It may also be slower. NAND-based
Flash is dirt cheap, which is good because you have to provide a bunch
of extra cells ... even on Earth, it is pretty much necessary to use
ECC, and to use wear-leveling algorithms.

Perhaps it was the ECC circuitry that triggered the failover. Note the
redundancy: the error(s) occurred on the A-side computer and the
B-side computer took over running the ship.

And Curiosity's project manager says this:
"The hardware that we fly is radiation tolerant, but there's a limit to
how hardened it can be," Cook said. "You can still get high-energy
particles that can cause the memory to be corrupted. It certainly is a
possibility and that's what we're looking into."
http://arstechnica.com/science/2013/03/flash-memory-issue-forces-curiosity-rover-into-safe-mode/


A quick look for relevant information doesn't lead me to any technical
data on the Flash memory involved (2GB per computer, per Wikipedia),
but I did see a comment by a veteran satellite programmer that there is
only so much you can do in hardware to protect from these sorts of
events (did it happen after a signficant solar flare?), so you always
have software looking for errors. Which is what happened here.

/dps

--
But happiness cannot be pursued; it must ensue. One must have a reason
to 'be happy.'"
Viktor Frankl


  #5  
Old March 19th 13, 07:29 AM posted to sci.space.station
snidely
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Posts: 1,303
Default Curiosity and other rovers issues with flash memory

On Monday or thereabouts, JF Mezei declared ...

It would be ironic if NASA were criticised for losing a ship because it
used cheaper technology. Genereally they are criticised for using
expensive tech.


Cheap is a relative term; the rad-hardening is probably the biggest
expense, and you can still expect to have upsets.


Do these rovers have any sensors to measure solar radiation ? Seems this
is an important metric to have if one is ever going to be building
shelters for humans to camp in during the first mars expedition.


I believe Curiosity is the first to be measuring that, and that the
instrument was specifically included as a preliminary assessment of the
human exposure.

Surprise! JPL has a web page for this instrument! I didn't even need
a secret handshake to find it!

http://marsprogram.jpl.nasa.gov/msl/mission/instruments/radiationdetectors/rad/

/dps

--
"This is all very fine, but let us not be carried away be excitement,
but ask calmly, how does this person feel about in in his cooler
moments next day, with six or seven thousand feet of snow and stuff on
top of him?"
_Roughing It_, Mark Twain.


  #6  
Old March 20th 13, 04:27 AM posted to sci.space.station
Greg \(Strider\) Moore
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Posts: 790
Default Curiosity and other rovers issues with flash memory

Snidely wrote:

The type of Flash memory is also important. NOR-based Flash tends to
be more stable, but costs more. It may also be slower. NAND-based
Flash is dirt cheap, which is good because you have to provide a bunch
of extra cells ... even on Earth, it is pretty much necessary to use
ECC, and to use wear-leveling algorithms.


It would be ironic if NASA were criticised for losing a ship because it
used cheaper technology. Genereally they are criticised for using
expensive tech.


But big pictu what does this say about the chance that life ever
existed on Mars ? Wouldn't an environment where solar radiation affects
electronics also reduce the chance that life would survive long ?


Do these rovers have any sensors to measure solar radiation ? Seems this
is an important metric to have if one is ever going to be building
shelters for humans to camp in during the first mars expedition.




Given we have found bacteria living in the water of nuclear reactors, I'm
sure stuff could survive on Mars. Especially since it most likely had a
heavier atmosphere millennia ago.

And given memory on Earth can be affected by radiation and we have plenty of
life (not always intelligent life) I think Mars would do fine.


--
Greg D. Moore http://greenmountainsoftware.wordpress.com/
CEO QuiCR: Quick, Crowdsourced Responses. http://www.quicr.net

  #7  
Old March 20th 13, 10:18 PM posted to sci.space.station
Jochem Huhmann
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Posts: 606
Default Curiosity and other rovers issues with flash memory

"Greg (Strider) Moore" writes:

Do these rovers have any sensors to measure solar radiation ? Seems this
is an important metric to have if one is ever going to be building
shelters for humans to camp in during the first mars expedition.



Given we have found bacteria living in the water of nuclear reactors,
I'm sure stuff could survive on Mars. Especially since it most likely
had a heavier atmosphere millennia ago.

And given memory on Earth can be affected by radiation and we have
plenty of life (not always intelligent life) I think Mars would do
fine.


Any life on Mars would be underground for more than one reason and
protected from this.

And there is even life down here (and not that primitive life either)
that is fairly unimpressed by such levels of radiation:

http://en.wikipedia.org/wiki/Tardigrades

Nice image he http://www.bbc.co.uk/nature/12855775

Evolution does wonderful things.


Jochem

--
"A designer knows he has arrived at perfection not when there is no
longer anything to add, but when there is no longer anything to take away."
- Antoine de Saint-Exupery
 




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