Mars rover Opportunity shuns dodgy flash chips, relies on RAM NASA says its aging solar-powered Opportunity rover will from now on explore the Red Planet without using its flash memory whenever possible. Opportunity has been on Mars since 2004, and it was expected to work for three months. Glitches in the rover's flash memory, which first became apparent with an ”amnesia” incident in …
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Expect creaks and moans from the suspension esp. when a storm is a comin', difficultly focusing the near-vision cameras, and generalized failure of both solid and liquid waste disposal systems. This will result in a steady stream of reports on said failures intermixed with retransmission of data collected in 2005-2006, and funny stories from a trip long ago when he and his brother left home for the last time.
I thoroughly agree. These rovers are an absolute marvel of engineering and its incredible they are still operating after all this time, given what Mars has historically done to kit.
Notwithstanding the physical conditions they have probably exceeded the warranty on the flash memory by some margin.
OK, Spirit got bogged down but that is an environmental issue rather than an equipment issue.
Curiosity can only hope to emulate its little brothers in the longevity stakes which sadly appears unlikely, given the issues it is experiencing with its wheels.
Weeeelll....
I'll be clapping along too, but not sure the comparison is up to much. I'd argue that VGER has an easier time of it, since all it has to do is keep on flying (falling?) in a more or less straight line, for which it doesn't even need propulsion after the initial push, and the only risks to its condition apart from unavoidable component failure -- environmental stresses, solar radiation and crashing into things -- are much lesser compared to what a rover trundling around on a planet's surface faces, and even lessening further as it travels further from the Sun and into less-occupied space.
Not only that, but it's really just doing what was expected of it; Spirit and Oppy, OTOH, ended up posing their "parents" the problem of coming up with more science for them to do up there, far beyond what was expected. Nice sort of problem to have, mind; not so much "First World problems" as "Fourth world problems" as it were.
After Philae's "miracle recovery", I'm wondering if it'll turn out to be the next "little robot that could".
"...VGER has an easier time of it, since all it has to do is keep on flying (falling?)..."
They're still going up* (at ~16 or 17 km/s), so they're certainly not falling.
* In this context, 'up' means 'up, up and away' from the gravitation attraction of the Sun and Solar System. Powered by momentum.
It'll be a very very very very long time before they do any falling.
And by confident, we mean confident enough to plan “several months” of activity in “Marathon Valley”, where the Mars Reconnaissance Orbiter has “detected exposures of clay minerals holding evidence about ancient wet environmental conditions.” En route, the vehicle has spent time exploring “Spirit of St. Louis Crater” and its intriguing “band of reddish material.”
Dear NASA,
I'm shocked that the 'band of reddish material' hasn't been given a name yet. I propose: Vulture Masthead
Yours expectantly,
=5
It was not "expected to work for three months". It was designed and engineered such that the chances of *any* of the sub-systems failing in the first three months was fairly low.
If you take that as the base line, and do the maths, the fact that *most* of it is still working 10 years later is no longer so surprising.
As you probably can't be bothered, I will do it for you.
Let us say that the rover has 20 sub-systems, and we want to be 90% sure that none of them will fail in the first three months. To achieve that, you need to engineer each sub-system such that it has a 99.5% chance of still working after three months. Which means that after ten years, (ignoring wear and tear), it'll have an 80% chance of still working. Which means you can expect about about four out of the twenty subsystems to have stopped working. Which, amazingly enough, despite the fact that I have been using makey-uppy numbers for illustration purposes, is pretty much what we have got.
I've done this here before.
Errr.. my understanding is that it was "expected to work for three months" due to predicted dust buildup on the solar panels deminishing it's power harvesting capability. Presumably based on Sojourner and past missions. Nothing to do with the overall engineering design.
Fortunately the environment worked in its favor in this respect.
This being the case, yes we are reliant on the engineering design which is bloody good to keep going for 10 years in a hostile environment however many millions of miles from the nearest engineer or technician.
The same fundamentals will have underpinned Curiosity's design but despite this, unforeseen issues will still occur.
http://www.space.com/29844-mars-rover-curiosity-wheel-damage.html
@Dom3 - spot on. It would actually be rather difficult (and stoopid) to design something to *only* work for 3 months. For it to be (as close as realistically possible) guaranteed to be operating after 3 months, you would expect its degradation to be in line with the decay curve you're describing.
"It would actually be rather difficult (and stoopid) to design something to *only* work for 3 months."
Old Polish joke (as payback for USAian jokes about Poles)
1st Polish Bloke: What's gray and sits humming on the windowsill for 91 days then goes silent?
2nd Polish Bloke: I don't know, I give up.
1st Polish Bloke: An American air conditioner with a 90 day warranty.
0.5% likelihood of subsystem failure in the first three months. 10% failure chance of the whole in the first three months???
You wouldn't accept that in a commercial product let alone something being sent into space.
You say the figures are makey-uppy, throw in an assumption called wear and tear and then come up with a number which amazingly (and you point out) fits the result.
Aren't you just making your makey-uppy numbers fit the observation?
"0.5% likelihood of subsystem failure in the first three months. 10% failure chance of the whole in the first three months???
You wouldn't accept that in a commercial product let alone something being sent into space.
"
Space hardware does not have the option of the development cycle of a commercial product. You usually only get to make 1 or 2 units, and even then have your testing on earth in simulated environments. Your development costs are amortized over 1 unit, and every fractional increase in computed reliability costs ever more. So you make a design tradeoff for reasonable reliability and non-infinite budget.
Re "Space hardware does not have the option of the development cycle of a commercial product."
Maybe so but like every other product development you don't go back to square one, you build on what has been successful previously. Components, sub systems, architectures.
The figures are admittedly made up by the original poster, I maintain they are not realistic design targets therefore the original argument falls over.
I remember pointing out Mars to my kids a few years back, and they were reasonably impressed at the red appearance. I then told them that two robot cars from earth were trundling about on that red dot in the sky (Curiosity had not yet landed). That lit up their imagination. For that alone I am very thankful to the engineers at NASA.
Kids! The beer is for dad, and for the engineers, not for you two!!
I suspect the solar panels are pretty fragile and the necessary engineering would have added significantly to the pay load. Alternative methods like dropping the panel down to vertical so the dust would fall off would I suspect be more likely but deploying and moving solar panels in space has IIRC has unfortunately been unsuccessful more than once:-(
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