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NASA Finds Cause of Voyager 2 Glitch

Posted by kdawson on from the blame-cosmic-rays dept.

astroengine writes "Earlier this month, engineers suspended Voyager 2's science measurements because of an unexpected problem in its communications stream. A glitch in the flight data system, which formats information for radioing to Earth, was believed to be the problem. Now NASA has found the cause of the issue: it was a single memory bit that had erroneously flipped from a 0 to a 1. The cause of the error is yet to be understood, but NASA plans to reset Voyager's memory tomorrow, clearing the error."

34 of 283 comments (clear)

  1. Sometimes, if you do things right... by BlackErtai · · Score: 5, Funny

    Nobody knows you've done anything at all.

    --
    -|BlackErtai|-
    1. Re:Sometimes, if you do things right... by angelwolf71885 · · Score: 5, Funny

      like burning down a bar for the insurance money

    2. Re:Sometimes, if you do things right... by Anonymous Coward · · Score: 3, Funny

      Yes, if you make it look like an electrical thing.

  2. Really? by atomicthumbs · · Score: 3, Insightful

    The cause of the error is yet to be understood

    Let me guess: cosmic ray. Is it really that hard? What else causes a single bit-flip error in space?

    --
    http://pinopsida.com
    1. Re:Really? by pclminion · · Score: 5, Insightful

      Let me guess: cosmic ray. Is it really that hard? What else causes a single bit-flip error in space?

      When you have a probe billions of miles from Earth, with no hope of ever physically retrieving it, and something weird happens, I don't think the first thing you do is start making assumptions.

    2. Re:Really? by mozumder · · Score: 3, Funny

      Let me guess: cosmic ray. Is it really that hard? What else causes a single bit-flip error in space?

      Incredibly annoying alien hackers?

    3. Re:Really? by sznupi · · Score: 4, Funny

      V'Ger is unwilling to just transfer the data to its Creator...

      --
      One that hath name thou can not otter
    4. Re:Really? by Peach+Rings · · Score: 3, Insightful

      It's pretty amazing that they even were able to track the problem down to a particular bit. No general purpose operating system has anything even remotely having dreams of approaching that level of reliability and stability. It's nice to see the strengths of bare-metal hacking demonstrated in this bleary age of big-button-pushing Java and .NET.

    5. Re:Really? by BitZtream · · Score: 4, Insightful

      Its also extremely important to note that not a single item you own is made to the specifications that Voyagers were made, even though made over 30 years ago.

      Its also rather important to note that as unstable as most OSes are, they are several million times more complex than the code Voyager 1 and 2 run.

      Finally, joke about Windows all you want ... if you do a default installation of Windows and you don't install any additional drivers or software, it is extremely stable and will just sit there for ages happy to do nothing but tick away.

      Its also entirely feasable to find 1 stuck or flipped bit even using Java and .NET, you just have to actually understand the inner workings of this code which is not something pretty much any developer working in these environments has time to do these days.

      Both things may be computers that run code and use electricity to do so, but thats about where the shared bits end. These guys have been using the same code for 30+ years ... they kinda know how it works and all its quirks at this point.

      With all that said ... you're still right, its freaky impressive.

      --
      Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
    6. Re:Really? by Anonymous Coward · · Score: 3, Funny

      Actually it was a metric "0" that got switched to an imperial "1".

    7. Re:Really? by ianezz · · Score: 4, Funny

      M-x butterfly. Cosmic rays, but on purpose.

    8. Re:Really? by 0123456 · · Score: 5, Informative

      It's pretty amazing that they even were able to track the problem down to a particular bit.

      To be fair, Voyager doesn't have many bits in its memory :). Tracking down a bad bit is much easier when you have 4k of RAM than when you have 4GB of RAM.

    9. Re:Really? by rew · · Score: 3, Interesting

      Certainty? I don't think so.

      I think they simulated Voyager with this bit flipped and saw the same output (that is transmitted to earth).

      I hope they tried to flip ALL bits, and found that only this one bit would give the results seen. If you would follow the code and find and test just a few likely places, I'd expect a few more unexpected places to give the same results.

      The quick fix is to send the correct byte to the craft and hope that fixes it. If the bit has become stuck in the new position, they will have to do a remote firmware upgrade (with the code rewritten to fit the stuck-at value...) Other memory cells may have broken down in the mean time, but with a stuck-at value that is correct for the current version of the firmware, which you won't know until you try them....

    10. Re:Really? by unts · · Score: 3, Funny

      I'm middle-endian, you insensitive clod.

  3. So.... reboot? by superdave80 · · Score: 5, Funny

    Why don't they just always try that first?

    1. Re:So.... reboot? by Brett+Buck · · Score: 5, Insightful

      Why don't they just always try that first?

              Because sometimes it doesn't come back on again.

            Brett

    2. Re:So.... reboot? by llvllatrix · · Score: 4, Funny

      Dude, uptime blog cred!

    3. Re:So.... reboot? by PePe242 · · Score: 4, Funny

      Hello IT, ... have you tried turning it off and on again?

  4. Re:Cosmci Ra by VValdo · · Score: 4, Funny

    What else would it be?

    According to some German, aliens.

    W

    PS is "Cosmci Ra" related to Mumm-Ra? Or She-Ra for that matter?

    --
    -------------------
    This is my SIG. There are many like it, but this one is mine.
  5. 33 years and still going strong - nuclear FTW by blind+biker · · Score: 4, Insightful

    This is why you DO WANT nuclear energy in space! OK, Voyager 1 and 2 have RTGs, but even those are considered politically incorrect these days, especially such massive ones as in the Voyagers.

    More nuclear power in spacecraft, I say. To provide propulsion (ion drive, or even better, explosive drive) and energy when far from the Sun. Fuck PC.

    --
    "The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
    1. Re:33 years and still going strong - nuclear FTW by PeterBrett · · Score: 4, Informative

      Something is so very, very wrong with your reasoning. If NASA couldn't fix the problem we wouldn't just have a bit of space junk spewing out garbage transmissions, we'd have a bit NUCLEAR space junk spewing out garbage transmissions.

      Oh no! What a terrible thing! There's nothing like that in space at the moment, how could we possibly manage?

      The Van Allen belts contain high enough concentrations of radiation that they make Chernobyl's fallout look like spilt milk. The sun regularly pumps out solar flares that would kill unshielded humans in seconds. Compared to that, I find it very very difficult to be at all concerned by a tiny spacecraft literally billions of kilometres away.

      That is a very bad idea for two reasons (assuming you're referring to project Orion and not completely off your tree). 1. Nuclear bombs are very heavy and very destructive, not only do you have the cost of getting them up there but you also have the very real possibility of them being detonated at slightly the wrong angle or slightly the wrong distance vaporising the craft (we are talking about NUCLEAR fucking bombs people) or any of the myriad of other unpredicted problems you will encounter in deep space. 2. Once out in space, you do not need continual propulsion, deploying an explosive drive means sending up two propulsion systems rather then just putting more fuel into the first.

      Oh dear, where do I start? Firstly, no, nuclear explosives (they're only bombs if you're dropping them on someone) are not necessarily "very heavy". They can be easily built small and light enough to fit into an artillery shell; if a serious Orion development programme was resumed, you'd be looking at 5-10 kg per charge, possibly less. In the Orion model, the pusher plate and damping structure are by far the most massive components. Secondly, nuclear explosions behave very differently in a vacuum than in air; most of the destructive power of a nuclear detonation on Earth is due to the way that the massive energy release affects the atmosphere. Thirdly, it's bloody hard to get a nuclear explosive to detonate. They can only detonate successfully if a very long and complex chain of events occur in precisely the right way. I think you overestimate the risk massively. Honestly, mining with conventional explosives is far more risky than propulsion using nuclear explosives will ever be. Finally, one of the biggest advantages of the proposed Orion propulsion system is that the mass efficiency is very high, meaning that it's possible to continue thrusting for a long period of time, so the whole point is that you want to use it "out in space."

      I recommend reading 'Project Orion' by George Dyson if you want to know more about the practicalities of the Orion propulsion system.

      Two massive hurdles prevent the use of nuclear reactors in space, weight and the ability to operate them safely from remote. First, nuclear reactors are very very heavy with all that radiation shielding.

      Which you don't need in space; you design the reactor so the majority of the radiation produced is directed away from the spacecraft. Look up NASA's SP-100 design.

      Secondly we can not guarantee that remote systems will operate, it's hard enough to keep a well maintained reactor on the ground operating without constant human intervention (which is why they have constant human intervention) let alone one that will be completely unmaintained and far far from any human help.

      No, modern reactors run on almost completely automated systems, even down to choosing which rods should optimally be replaced next. Human intervention is only required when modifying output to match grid loads (and even then, that's largely automated too). Even if something goes wrong, modern reactor safety systems have so much redundancy and fail-safe assumptions

      --
      Pirate Party UK
  6. Hero by LoudMusic · · Score: 5, Insightful

    NASA is my hero. They do cool shit all the time. Even when their stuff breaks, it's cool. Then they fix it and it's even more cool.

    --
    No sig for you. YOU GET NO SIG!
  7. Just incredible! by mcrbids · · Score: 3, Insightful

    Voyager is anything but brand new. Voyager is probably older than most Slashdotters, having been launched in 1977. Think about it: 1977 - when advanced microchips were not as powerful as the chip driving the shatty calculator you buy today at the dollar store. 1977 was a different time, when information technology usually didn't even involve transistors, yet, and vacuum tube testers (for your TV) were still found at the local drug store.

    And yet, some 33 years later, Voyager 2 is still chugging on, after visiting ALL of the outer planets, still going waaayayyyyyyy past its original design limits, still providing meaningful information on its way out roughly towards the star Sirius. It's now twice as far away from the Sun as Pluto is.

    Like the Mars rovers, this is truly good engineering at work.

    --
    I have no problem with your religion until you decide it's reason to deprive others of the truth.
    1. Re:Just incredible! by fdrebin · · Score: 5, Informative

      1977 was a different time, when information technology usually didn't even involve transistors, yet, and vacuum tube testers (for your TV) were still found at the local drug store.

      Tube testers were pretty darned hard to find almost anywhere in 1977 (you could find them in old-used-electronics stores). I do recall testing tubes in drugstores in the early 70's.

      Solid state, and even (*gasp*) integrated circuits were in widespread use. Why, by gosh by golly, we even had *8080*'s then.

      I was a senior in college in physics+EE; I and a handful of my fellow students managed to coerce one of the EE profs to take a few hours and teach us about tubes (they had been removed from the curriculum). For the most part the interest was for us audio-nerds... tubes had that nice desirable sweet sound... (but I digress)

      /F

      --
      Stupidity... has a habit of getting its way.
    2. Re:Just incredible! by Hurricane78 · · Score: 5, Insightful

      tubes had that nice desirable sweet distortion...

      There, fixed that for ya...

      --
      Any sufficiently advanced intelligence is indistinguishable from stupidity.
    3. Re:Just incredible! by vlm · · Score: 5, Informative

      1977 - when advanced microchips were not as powerful as the chip driving the shatty calculator you buy today at the dollar store.

      Classic, ever repeated confusion of what "power" is. Unless you mean volts times amps, power is what you can do with it. An old mainframe can run a department of a small multinational corporation, maybe a large university, or perhaps a division of state government. We know this, because they did in fact do so, very profitably. You claim a dollar store calculator is more powerful. That means a dollar store calculator should be able to run, say, an entire multinational corporation, maybe multiple universities, or an entire state government. Oh wait, a dollar store calculator can, at best, slowly calculate someone's income tax, possibly correctly. I guess the old mainframe is more powerful after all.

      When I worked at a mainframe shop in the late 90s I heard alot of similar tiresome comments... "Ha ha, mainframes, bet you didn't know my laptop can run NOPs faster than your mainframe can run floating point FFTs ha ha ha mainframes". At which point you simply tell them to put up or shut up, hand them a bus and tag cable, and have their infinitely "more powerful" laptop process 5% of the NYSE volume like our mainframes did, while supporting about 100K trader desks, a couple TB of tape robot storage, etc.

      --
      "Science flies us to the moon. Religion flies us into buildings." - Victor Stenger
    4. Re:Just incredible! by commodore64_love · · Score: 4, Interesting

      >>>have their infinitely "more powerful" laptop process 5% of the NYSE volume like our mainframes did, while supporting about 100K trader desks, a couple TB of tape robot storage, etc.

      A laptop could do that if it had an efficient assembly-written OS (like Kolibri), rather than the bloated general purpose OSes like Windows NT or OS X. At my former company we used the equivalent of laptops (Pentium 2s) to manage, load mission data, and launch a ship full of Tomahawk missiles.

      --
      "I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
    5. Re:Just incredible! by Anonymous Coward · · Score: 4, Funny

      Classic, ever repeated confusion of what "power" is. Unless you mean volts times amps, power is what you can do with it.

      Have you ever kissed a girl?

    6. Re:Just incredible! by khallow · · Score: 4, Funny

      Have you ever kissed a girl?

      This is the wrong place to ask for dating advice.

    7. Re:Just incredible! by Anonymous Coward · · Score: 4, Informative

      Exactly. The IBM 360 had a truly incredible I/O capacity, powered by multiple parallel processing elements called "channels." You programmed them with "channel command words" or CCWs. They were independent of the main CPU. When a channel needed memory, it got locked down (pfixed) and allocated to the channel, so the channel could piss into memory at high speed. Really large, thick cables connected the CPU with peripheral devices. These cables had lots of wires in them. Because lots of bits were flowing IN PARALLEL. Look up the transfer rate of a 2701 drum drive, still maintained and used for paging devices as late as the 1980's by companies who could not find anything faster.

      When DEC tried to claim that they could replace 360's with VAX's, guess what happened? They didn't have massively parallel I/O processors. They didn't have a massive transfer capability. They generated an interrupt on every character typed by every user, for God's sake. They were not I/O engines. They failed, utterly. Not that VAX wasn't a good machine, but no way could it replace a 360.

      How did a small 360 support hundreds of users? Why, through an innovation called "CICS." What happened was, the mainframe would fill a 3270 CRT terminal screen with a "form." You would fill in the form, locally, using the "smart" 3270's field-editing and checking capability, with no interaction with the mainframe. When you were finished filling in your form, you'd hit TRANSMIT. At which point, the variable data on your form would be glued together by the 3270 in one record and sent up for processing by the mainframe (along with everyone else's form data). A few seconds later, you'd get another form in response. Lather, rinse, repeat.

      Oh wait. That's exactly how most business Web applications work. Except the screens are prettier.

  8. Re:What!? No parity checking?! by mjwx · · Score: 3, Funny

    Must suck waiting 26 hours to find out if the reboot worked...

    Nah, thats just like rebooting a Windows 2003 server. 14 days and it's still "Applying Computer Settings"

    --
    Calling someone a "hater" only means you can not rationally rebut their argument.
  9. New-fangled memory by dfsmith · · Score: 5, Informative

    One of the upgrades the Voyagers had over the Viking computers was CMOS memory (instead of plated wires). Read all about it at http://history.nasa.gov/computers/contents.html Apparently, there was some debate at the time over whether these new-fangled memories would be reliable.

  10. Reset the memory? by KlausBreuer · · Score: 3, Funny

    Well, okay, as long as they don't get the "Press any key to continue" message...

    --
    Free PC version of ChipWits at http://www.breueronline.de/klaus/chipwits/
    1. Re:Reset the memory? by Rocketship+Underpant · · Score: 3, Funny

      NASA technician #1: Voyager 2 is sending a text string to inform us of its status.

      (Looks at screen.)

      NASA technician #2: Did the reboot work? What does it say?

      NASA technician #1: "Keyboard not found. Press F1 to continue."

      --
      He who lights his taper at mine, receives light without darkening me.