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Mars Rover Opportunity Turns 8
New submitter el borak writes
"Never mind all the talk about the revival of the American auto industry. What may be the greatest car the U.S. has ever built is currently a tidy 78 million miles (125m km) away from this world — resting on the edge of Endeavour crater in the southern hemisphere of Mars. It was on January 25, 2004 that the rover Opportunity bounced down on Mars for a mission designed to last a minimum of three months and a maximum of just a year or two."
Cars carry human passengers - pretty much the definition of car. This is a rover and not a car.
Can you remember the last piece of technology hardware you had which outlived its warranty? For me, most of that was stuff made in the 80's.
Considerable accomplishment, designing, accumulating all the bits, assembling it, putting it in a rocket, flying it to Mars, landing it and having it muck about in a place without AAA Roadside Service. Well done.
A feeling of having made the same mistake before: Deja Foobar
Images from Opportunity show a life form consisting of a scorpion-shaped body, a disc and a 'black flap".
1) IT did not actually put those 78 Million miles on its own hardware, its like if I ship a toyota from japan to virgina, I did not DRIVE it from A to B and I shure as hell would not add the shipping mileage to its odometer
2) Are we really that proud that something we built lasted 8 years? that's like the breaking in period for a diesel Mercedes with far more (actual, not shipping) miles on it
Kudos to the Design team.
well done.
I don't know what you have over there but these engineers deserve to be knighted.
Seriously, it's time to get a life. If you get paid to do this, it's time for some self reflection.
The impressive aspect is not that it has operated for 8 years, or that it is "beyond its warranty" (which is a misnomer - there was no warranty). What is impressive is that it has operated in a harsh environment for 8 years WITH ZERO MAINTENANCE! None. No one has touched the device in over 8 years now. And it has continued to operate, by radio, despite dust, vibration, heat, cold and radiation beyond what most Earth-bound devices ever experience.
Sure, my car has well over 100K miles on it and is over 12 years old. But it is only operating because I am performing routine maintenance on the car. If I had not maintained the car, it would have stopped working ages ago. The impressive aspect of the Mars rover is that it has survived without anyone needs to tighten a nut, change oil, replace a battery or wheel or any of the routine operations that we have to use for our normal machines to keep them operational.
Do you understand that the -400% life you consider as a possibility means it would have failed before it was built, and possibly before it was designed?
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This was the cheapest mission to Mars we've ever done. That is a fact. That the rovers lasted this long means we got a lot more out of our money than we thought. You're not knocking NASA engineers, but you are, and you're doing it by omitting a few key facts.
Slashdot is intentionally not providing you full tech news coverage because it caters to a specific demographic of emotionally-invested users who are more likely to generate repeat page views.
You are right, we really don't give a shit so shut the fuck up and go away.
There is no reason to post a story about it considering all your stupid fucking copy paste trolls IN EACH AND EVERY FUCKING THREAD YOU FUCKING RETARD!
Thank you and fuck off.
They designed these things to withstand the worst environment they could imagine and be as durable as possible since maintenance would be impossible. Maybe they overcompensated, so what? In return they got 4x the lifetime and dozens of times the science that they had hoped for, and still counting. Your complaint is idiotic. It's like complaining there's too much cake.
"I disapprove of what you say, but I will defend to the death your right to say it." - Evelyn Beatrice Hall, re Voltaire
That must be in dog years.
Bah-dah-bump. Be sure to tip your waitress. Thank you.
Have gnu, will travel.
Estimates were based on experience with the earlier Sojourner rover. Opportunity got lucky in that every now and then whirlwinds clean off the solar panels. This phenom was not known at the time, at least with solar panels.
And the wheels and joints have become creaky and are gradually failing. Work-arounds and adjustments to behavior have allowed it to continue. Thus, the equipment is failing, as expected. Luck and ingenuity in work-arounds should not normally be relied on for engineering duration estimates. Further, the grinder teeth have worn down and the rover is basically gumming rocks, or just brushing rocks instead of grinding.
Table-ized A.I.
1) Project Managers give estimates, not Engineers
2) Estimates are based on historical data, the less historical data you have the more VAR factors into your estimate.
3) This has NEVER BEEN DONE BEFORE, thus a Var factor of 4.0 is probably on the low end of the scale.
4) Calling them bad engineers because their estimation technique took into account the lack of historical data, is a disservice to both project management and engineering
5) Your an idiot. Your 'an idiot' wrote your post.
I don't believe it's the cheapest. Pathfinder/Sojourner, for one, was less.
Table-ized A.I.
The problem is you're working on a scale that's starting at 0. If it fails at 90 days (the mission objective) that's 100% success. If it fails at 45 days, it was a 50% success.
Your scale is wrong.
The mission was for 90 days, meaning anything LESS than 90 days would count as a failure, or 0%. 45 days? 0%. 89 days? 0%.
So they were overengineered for the express purpose of guaranteeing 90 days.
It may be dumb luck. What you have to keep in mind is that the margin of error necessary might be so high that even a good engineer cannot narrow it down to a small number. In this case, it could be the durability necessary to get the rover to run for a month is the exact same durability that would allow it to run for years.
Clearly you aren't and never will be an engineer, we all have different strengths.
The point of engineering is to have "just enough cake." Not too much (overdesign), not too little (underdesign).
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"Opportunity cost" if the device fails before the design lifespan.
The device might be cheaper than the rockets, fuel etc involved in sending it there.
Sometimes you also need to launch something within a particular time range, otherwise the next best time could be decades or even a century later: http://en.wikipedia.org/wiki/Launch_window
So if you launch it and the stuff fails, you just wasted many millions and many years. The scientists who wanted it there for their research might die before the 2nd try.
Just because they erred on the side of a good result doesn't mean the estimates are better. It means their methodology is HEAVILY padded
Under promise, over deliver. I wish more organizations/projects had this "flaw".
The rover's aren't like the Deacon's Masterpiece, where every component reaches end-of-life at exactly the same time, the mission life was dictated not by component life but environmental factors. As I understand it, the relatively short life-rating was based largely on power availability. From all previous Mars landers, it was expected that the solar panels' output would drop to useless levels within a couple months of landing. And although they surely had some ideas on how to get the rovers to survive the Martian winter, they certainly weren't going to make that a mission requirement. The mission life wasn't a matter of the rated life of the motors, or the computers, or of the fatigue life of the chassis. You couldn't have really made them cheaper and still had a usable rover: a strut with a fatigue life of only a few months' driving probably may have snapped on impact, a 1-year motor would have been more or less the same size and weight, a 1-year computer would have been identical to the computer they've got.
And, really, why would you want to shave everything down to such a short life: it's not like you could have saved much money for the taxpayer - the component cost of the rovers is only maybe 1/100th the total cost of the mission. Most of the cost is in getting the rover to Mars in the first place, followed by having a full-time staff of dozens or hundreds designing, testing, and running the thing.
It would have taken more time to design and build cheaper parts.
Only idiots on /. would think the something going about it's expected life for the same money is bad engineering.
The Kruger Dunning explains most post on
They were designed to be GUARANTEED to work for 3 months, which typically means that the usable lifetime is considerably longer. Pretty standard engineering stuff.
Someone sounds a little bitter. What's the matter, NASA turn you down for a job?
"I disapprove of what you say, but I will defend to the death your right to say it." - Evelyn Beatrice Hall, re Voltaire
There was a bare minimum that this rover had to be engineered for. That bare minimum to make sure it worked at all is what also allowed it to last as long as it has.
This rover landed via airbags and experienced some tremendous g-forces. The rover had to be designed to survive that, just the ability to scoot around after that in a low gravity environment was cake compared to the landing.
So if they had designed this to just barely hit the 90 day limit then it might not have survived at all.
Don't know something? Look it up. Still don't know? Then ask.
Obligatory xkcd: http://xkcd.com/695/
Insert signature here...
There's talk of the revival of the American automotive industry?!? Are there more bailouts or something?
This does appear to be a concerted astro-turfing campaign.
Not because it goes against the grain here at /. , but because these fucking morons are posting it in every single fucking story.
Most individuals would have given up by now, perhaps figured their point got across, but this troll just keeps on posting on and on, in every single fucking thread, every single one. Just like those fucking annoying people who post advertisements in the middle of threads.
If it has been two or three threads I could buy the idea that it was a concerned individual, but at this point no.
If it is indeed a concerned individual, and he is reading this, please stop, you are hurting your cause tremendously. You made your point quite some time ago, now you are being counterproductive.
5) Your an idiot. Your 'an idiot' wrote your post.
I'd like to make a helpful suggestion. When you are chiding someone for being wrong (and, he was), it's incumbent upon you to be right. That means grammar, too.
"Your" is possessive. "You're" is a contraction of "you are."
Clearly you aren't and never will be qualified to be an engineer. Hopefully you have other strengths that make you valuable to your employer, like contributing to team morale by telling good jokes.
First thing you don't understand: When the conditions in which something will be used are subject to a great deal of uncertainty, you err on the side of "overdesign". Mars is another planet about whose surface conditions we still have limited information, eight years into this mission.
Second, when the potential consequences of failure are "go grab another one and put it in service" you engineer something to be "just good enough". But when the potential consequences of failure are the cancellation of the whole project, including years of work by hundreds of people, imperial truckloads of money, more people's ongoing jobs, and the lost opportunity to profoundly advance human knowledge, you engineer something to be "substantially better than enough".
You're missing that these are _exploration_ missions. Part of that means there are a lot of variables we don't know about. That means padding the tolences a bit, but also that the unexpected _does_ happen. If the events that cleaned the solar panels had not occurred, for instance, Opportunity would probably not have lasted this long.
Which is strange, because during his interview he kept stressing to them that he was "just good enough" for the job.
NASA deserves little credit for the MER rovers (i.e. Spirt and Opportunity), in fact I suspect that the human-spaceflight ex-pilots at NASA/Houston would prefer to nuke all unmanned mission and dump (waste) all the funding on more manned pork. The MERs are JPL all the way. Do not confuse the money-pit, scientifically-impoverished manned missions of NASA with the low-code (comparatively), successful missions of JPL. Opportunity is one of the most successful missions ever flow, right up there with Voyager and Cassini. Compare that with the Shuttle...
This was how the project got off the ground. If it was expected to last 10 years, the budget would have looked too large, and the pencil pushers would have killed the project. Leave the techs alone, and good stuff happens.
You are being MICROattacked, from various angles, in a SOFT manner.
I think it is great that the device was design to last max a year or two, and lasted 8, but on the flipside, this means they aren't really good engineers.
First of all it was engineered to guarantee to work for 3 months which was the allotted project objectives. Based on the budget and capability, this is what NASA had designed the rovers to do. Surviving for years is a bonus.
Just because they erred on the side of a good result doesn't mean the estimates are better. It means their methodology is HEAVILY padded, or if we assume +/-400~800%, they were just lucky that it didn't swing the other way. Given Phobos-Grunt, perhaps space engineering margin of error really is +/-400~800%. Although I suspect huge margins of error were thrown about in NASA>
Of course they padded their estimates and erred on the side of caution. 1) There is no way to retrieve or repair this rover. 2) NASA knew about the sticky dust from previous missions, but they didn't have omnipotence when it comes to the Mars climate. They didn't know that windstorms were capable of cleaning said dust. So you would have rather just wing it and not pad their estimates. So when the rover failed, they can tell NASA "oh well, try again in two years."
If that's the case, huge design buffers, that means they don't understand the underlying physics/materials engineer, and had to heavily overdesign, which means there is a far more efficient design out there.
I don't think you understand that there are different goals in engineering. One goal may be efficiency. The goal in this case was absolute reliability despite any unknowns the rovers may have experienced on Mars.
I'm not knocking NASA engineers, I'm just exploring how to shave down this margin so that they can make more efficient designs at lower cost that behave as expected.
Again efficiency is not as much a priority as reliability in these cases.
Building something that behaves as expected is far, far, FAR more important than building something that blows away expectations by orders of magnitude. The former is good engineering, the latter is waste, or worse, dumb luck!
The engineers never worked on the expectation that you ascribe. People outside of NASA have placed it on them. For them, the mission was successful when the rovers completed their objectives after 3 months. All these years afterwards are bonus.
Well, there's spam egg sausage and spam, that's not got much spam in it.
...if they only had included a wind shield wiper on the solar panel...
Look around, pal. This spam is popping up as the first post on every damned article. FTFY
See I am an engineer. And for some situations, it is best to way way over engineer something to ensure that the system NEVER fails. In my field, this typically involves safety systems. Seeing as I never want to be responsible for someones head getting crushed I put as much redundancy into the safety system that I can get away with. That is also how the legislation about safety is written, with dual redundancy all over the place.
In the mining industry, where safety is paramount. They typically have entire redundant control systems to ensure no downtime. The systems are designed to last 20-30 years but get replaced every 5 years to make sure that nothing goes wrong ever.
In the case of a vehicle that will never be able to be serviced and costs hundreds of millions of dollars to get to its destination, its fully understandable and expected that it will be over engineered.
Clearly you don't understand the engineering tradeoffs being made here. This isn't a sewer or a bridge. Launch costs are astronomical.
At least you're not one of those "Why didn't they install windshield wipers?" morons.
And that is exactly what the troll wants.
Just don't feed the trolls, and they will die in painful death.
(To be honest I am feeding him now as well, so I promise that is my first and last post on this topic)
Here are the Level 1 System Requirements for MER.
http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37720/1/05-0470.pdf
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The Russian Lunokhod explored the moon for five lunar days in 1973. It those days it was driven in real being a little more than a light second from Earth.
You are completely making my point:
You said:
"In the mining industry, where safety is paramount. They typically have entire redundant control systems to ensure no downtime. The systems are designed to last 20-30 years but get replaced every 5 years to make sure that nothing goes wrong ever."
Why not build systems to last 100, 1,000 or even 100,000 years if you care so much about safety? Because 100,000 reliability, even to the non-engineer, sounds like overkill. But you yourself, as an engineer, claim that your system should NEVER fail. But you said 30 years was enough. That is NOT NEVER! It is 30 years.
Why didn't you design for "NEVER"? Because it would be an astronomical cost.
The engineer has to figure out how to build for 30 years, and not for 1,000, and not for 5.
Just as I said: enough cake.
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Your post is the most important and cogent point yet.
I think that without being able to examine the vehicles, we cannot tell what or where the failure points will be. Therefore it is difficult to tell what to engineer to fail earlier (or hopefully all at the same time). It would depend too on whether this more efficient design is in fact lighter/cheaper/smaller, etc. Perhaps the over-engineered parts that have not failed yet are the lightest and cheapest that can be made in a Mars rover.
That's exactly what was cooking in my head, but never heard of it before: Deacon's Masterpiece. Yes! I was actually thinking in my head, the perfect engineering solution would be one that last exactly the allotted time then disintegrates, at optimal cost. I didn't know there was a term for it.
I like the next step in the discussion, the statement: "the strut that lasts a few months' time, but would snap on impact." Does this mean that the most perfectly "Deaconized" subgroups/subcomponents cannot be assembled into one device that meets the "global Deaconized requirement". Seems like a paradox at first: if every part is built to meet its minimum requirements, shouldn't the entire design meet its minimum requirements???
It feels like this is an ancient question... but I never actually studied the history of engineering while at engineering school.
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This site does not post every single news story out there, at this point this story is so fucking old No One Gives A Shit.
Should /. post a story about how Arch Duke Ferdinand was assassinated? It may be important, but at this point it is kinda old news.
I keep hearing about this mission, and I'd like to start a movement that part of the MSR mission will be to retrieve the rover from Mars and bring it back to Earth for evaluation, because I believe that examination of the rover after surviving for so long beyond it's original design lifetime will be very educational.
Are YOU using the TOOL, or is the TOOL using YOU? Think about it!
"I think that without being able to examine the vehicles, we cannot tell what or where the failure points will be."
I agree, some of the other comments explain that this is a "point and shoot" mission, without a chance to inspect the design for further engineering feedback. Someone else posted about a think called "Deacon's Masterpiece" in response to my over/under design statement, which is where I was headed. But like you said, without examining it, other engineering methods need to be employed.
In hindsight, I was playing devil's advocate, and probably should have started with that to avoid all of the flames!
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I like how there's always 1 positive mod, the rest being negative. We can clearly see that it's modding itself.
Within the payload limits, there's no reason not to over-engineer the hell out of a space platform. Value engineering a rover closer to the mission plan would have saved time/money, but would have added to the risks of failure. Utter mission failure is the major cost sink for working in space, so it pays to add sigmas when possible.
The critical variable is the limited number of opportunities for interplanetary launches as a function of time and lining up rockets. NASA could be lofting $1000 Aibos with high gain antennas stuck in their okoles. but, if our little pals don't return any data, you didn't save $300m on the probe, you pissed away $120m on the launch.
Luke, help me take this mask off
The next Mars rover that's nuclear-power will fail due to, 1st, poor coolant (e.g. water, cooler, etc.) for this specific purpose, 2nd failing electronic systems due to the ausence of plumb shield near to the radioactive core.
We've an important question: "how to accomplish the fullfilment of the prophecy when the man/woman abandons the Earth?".
Why to put we in risk our lives when few individuals wanted evilnessly to success their own "evil mission" for their own private interests?.
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The estimates were off by 400%~800%!!! Or more!!!
Just because they erred on the side of a good result doesn't mean the estimates are better.
It's like my gramps taught me: "It's better to have it and not need it than to need it and not have it."
Don't deserve to be modded troll!
The main reason something like the rovers were vastly over engineered was specifically due to lack of knowledge and experience. Remember the original Viking landers did not move so NASA had little experience with mobile rovers. Mars Pathfinder had the Sojourner rover but it never moved very far from the base station. This was the first time that NASA was deploying a true rover. As more missions are deployed engineers are using this experience as NASA and the JPL would love to put more instruments on these rovers. But the bare minimum has to be that the rovers are guaranteed to last as long as the original objectives.
Well, there's spam egg sausage and spam, that's not got much spam in it.
The point of engineering is to have "just enough cake." Not too much (overdesign), not too little (underdesign).
But now imagine your equipment is going somewhere that you know very little about (this being the whole point of why you're sending it), and there is no possibility for repair, upgrade (outside of software), or second chances.
Now are you going to aim for "just enough", or are you going to err on the side of over-design? How are you going to determine what "just enough" is, when you don't know what the environment will be like?
The correct way to engineer something like the Mars rover was not to try to make it "just enough". The correct way to engineer them is to make them as robust as can possibly be made, within the mass budget.
And this isn't the only situation where optimizing for the exact amount required is bad engineering, and optimizing the amount that can fit within other constraints is good engineering.
"Just enough" engineering is only one kind.
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