Artist impression of Voyager. Image credit: NASA/JPL

Voyager 2 Update from Dr. Ed Stone

Article Updated: 24 Dec , 2015

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In early May 2010, the 33-year-old Voyager 2 spacecraft experienced an anomaly where the data it returned to Earth was unreadable. Engineers diagnosed the problem as a flip of a bit in the memory in the flight data system computer that packages data to transmit back to Earth, and were able to successfully reset the computer. On May 23, Voyager 2 sent back data that was again formatted properly, but the teams wanted to check out all the systems on the spacecraft to make sure everything was working properly. We checked in with Dr. Ed Stone, former director of JPL and the project scientist for the Voyager project since 1972 to get the latest news on how Voyager 2’s checkout is progressing.

“The science teams have confirmed that Voyager 2 is again transmitting science data in the expected format and the instruments are fully functional,” Stone said via email. “The only remaining action is to reset the clock in the spacecraft’s data system that lost time while the memory bit was in the wrong state. The reset commands will be sent to the Voyager 2 in the next two weeks.”

The flipped or bad bit in the flight data system was likely caused by a cosmic ray that slipped by the radiation protection on the spacecraft. Since the computer stores information in ones and zeroes, a cosmic ray hit can change the value of a memory bit. The concern was that the flipped bit took place in an important location that could have a serious effect on the spacecraft, but fortunately, the problem was solved “easily.”

I say easily in quotes because of the complexities of diagnosing and fixing a spacecraft at such great distances. Since Voyager 2 is about 13.8 billion kilometers, or 8.6 billion miles, from Earth, it takes nearly 13 hours for signals to reach the spacecraft and nearly 13 hours for signals to come down to NASA’s Deep Space Network on Earth.

Hats off to the scientists and engineers at JPL for their efforts and dedication so we all can continue to follow Voyager’s continuing journey to interstellar space.

Sources: JPL, email exchange with Dr. Ed Stone, Planetary Blog.


17 Responses

  1. Drunk Vegan says:

    It’s a bit humbling to think that the farthest reaches of our solar system still only involve a 26-hour round trip lightspeed trip. The nearest star, however, is 4.3 light-years away, or about 1581.6 days (one-way) at lightspeed.

    And that is only a tiny fraction of the time it takes to travel any significant distance within our galaxy, much less the universe at large.

    Sol and her children within the heliosphere are unimaginably tiny…

  2. IVAN3MAN_AT_LARGE says:

    Drunk Vegan:

    Sol and her children within the heliosphere are unimaginably tiny…

    Which is why some of those children cannot let go of the ‘god’ security blanket…

  3. Torbjorn Larsson OM says:

    The _real_ Voyager anomaly. The good news is that the bit flip rate seems low.

    Sol and her children within the heliosphere are unimaginably tiny…

    Yes, but Voyager 2 is 92 au away. The Oort Cloud is, apparently, ~ 50 000 – 100 000 au or ~ 1-2 ly in radius. So we will have to wait some more before Voyager has metered out the system.

  4. Hon. Salacious B. Crumb says:

    Drats. Those aliens infiltrators were looking good for a while!

  5. tripleclean says:

    Hi,

    I could any one explain what type science data is being transmitted back to earth. Do the cameras still work? thanks.

  6. jjv says:

    Sol and her children within the heliosphere are unimaginably tiny…

    Which is why some of those children cannot let go of the ‘god’ security blanket…

    **************************************************

    The Left (of which you are a member, for sure) always seems so smug and proud of their “non belief” in God.

    Belief is free and brings comfort and inspiration to many. It is believed that at death believers who have lived a good and decent life will spend eternity with their God. This will bring to them eternal happiness, not a bad thing.

    OTH, according to Scripture, a non believer, whether he/she lives a good life or not will never enter the Kingdom of Heaven and will suffer eternally for their non belief.

    The question I put to you atheists is this and it is the very same one you on the Left pose to any who are against attempts to moderate any attempts to engineer what is referred to as climate change, or back in the 1970’s environmental hazards such as acid rain, etc. At that time whenever proof was brought forth claiming the hysteria over the “end of it all” chattering was over done, the response from the Left was always the same and it was, “Suppose you are wrong.just suppose. What harm then will come from an attempt to improve things”

    So, what harm comes with a belief in something better after death if that belief causes one to live a better life?

  7. Ooh a reality moment.

    I had lunch in the cafeteria with some of the operations folks at Canberra DSN on Saturday.

    Me: So, hey – I hear there’s a glitch with Voyager 2?

    Guy who works for freaking NASA: Oh yeah, it’s just a flipped bit, everythings OK now.

    Me: The old flipped bit again, huh? (nods wisely and googles flipped bit when at safe distance from cafeteria).

  8. Torbjorn Larsson OM says:

    @ jjv:

    First, nitpicks:
    – Atheism is rejection of religion, not hankering to ideologies. If anything, people who are skeptics can be suspicious to ideologies.

    – There is no “Left” ideology. You may mean liberals vs conservatives, which is the main spectra AFAIK.

    Second, your OT topic. Thank you for confirming IVAN3MAN_AT_LARGE’s model, not that we needed that. Indeed it is a needless security blanket.

    The post-semitic death cult is especially pernicious to a sane judgment of facts. It is the knowledge that life is short that gives depth to the wonders of the universe that we see.

    And please, making the daft Pascal’s wager is not an argument.

  9. IVAN3MAN_AT_LARGE says:

    @ jjv:

    The Left (of which you are a member, for sure) always seems so smug and proud of their “non belief” in God.

    For your information, I am apolitical as well as an atheist — hence the suffix “3MAN” (Freeman) to my name.

    So, what harm comes with a belief in something better after death if that belief causes one to live a better life?

    That belief is your prerogative; however, it’s when religious fundamentalist busybodies endeavour to impose their ‘beliefs’ on me and my fellow comrades, by insisting that the Earth is only 6,000-years-old(!), that dinosaurs ‘walked’ with people, and that ‘light was much faster’ in the past, then I have a problem with those people.

  10. Aodhhan says:

    What harm is there in a “white lie”?

    One man’s security blanket is another man’s ball and chain.

    “a better life” is a very subjective term.

  11. IVAN3MAN_AT_LARGE says:

    @ jjv,

    P.S. Evolution happened — DEAL WITH IT!

  12. jim.powers says:

    There is also a distinct difference between atheists and people who are antireligious.

    Simply:
    Atheists do not believe in god.

    People who are Antireligious are bigots. Your belief or disbelief in god does not matter in any way to me. How you treat others.. well, that’s a different story.

    Using any criteria to judge someone beneath you is as primitive as it gets. Tolerance for all the ways that people are different is the path to true enlightenment.

    Now, can we talk about Voyager?

    It’s kind of crazy to me that they were able to figure out what was wrong from so far away. Pretty awesome if you ask me, especially considering that lots of the guys who worked on the program before it left earth have retired, moved on or passed on. It shows a great deal of effort and time have been put into documenting things, and passing on knowledge so that these kinds of issues can be resolved.

    Great job to everyone who works on this, and every project out in space. It really is mind blowing what we can do when we go All-In as a species.

  13. IVAN3MAN_AT_LARGE says:

    @ jim.powers:

    It’s kind of crazy to me that they were able to figure out what was wrong from so far away. […], especially considering that lots of the guys who worked on the program before it left [E]arth have retired, moved on or passed on. It shows a great deal of effort and time have been put into documenting things, and passing on knowledge so that these kinds of issues can be resolved.

    That’s why all computer programmers (including me) are taught to draw up a detailed flowchart showing each stage of the software in question — not only for the benefit of other software engineers, who may need to address any issues at a later stage, but also for the original programmer (especially me!) when he needs to debug the bloody thing!

  14. ND says:

    Anyone know the hardware used for the computers on the V’gers?

  15. IVAN3MAN_AT_LARGE says:

    @ ND,

    It has been claimed that the “V’gers” were controlled by a version of the RCA (CDP)1802 “COSMAC” microprocessor, but it was not available at the time those spacecraft were being designed, and primary sources describe the Voyager computers as having architectures very dissimilar to the 1802, and not being microprocessor-based.

    There are three different computer types on the Voyager spacecraft and there are two of each kind. Total number of words among the six computers is about 32K.

    Computer Command System (CCS) – 18-bit word, interrupt type processors (2) with 4096 words each of plated wire, non-volatile memory.

    Flight Data System (FDS) – 16-bit word machine (2) with modular memories and 8198 words each.

    Attitude and Articulation Control System (AACS) – 18-bit word machines (2) with 4096 words each.

    Source: What kind of computers are used on the Voyager spacecraft? (Scroll down.)

  16. ND says:

    Thanks IVAN3MAN. Good info. Amazing what’s possible to accomplish with such hardware.

    “the computers were manufactured by General Electric to JPL specifications.”

    So these appear to custom hardware and not commercial ones.

    I’ve always wondered what sort of computer system were on those probes.

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