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Programming

The Ultimate in Debugging 41

Mark Rainey: Engineers are currently debugging why the Voyager 1 spacecraft, which is 15 billions miles away, turned off its main radio and switched to a backup radio that hasn't been used in over forty years!

I've had some tricky debugging issues in the past, including finding compiler bugs and debugging code with no debugger that had been burnt into prom packs for terminals, however I have huge admiration for the engineers maintaining the operation of Voyager 1.

Recently they sent a command to the craft that caused it to shut off its main radio transmitter, seemingly in an effort to preserve power and protect from faults. This prompted it to switch over to the backup radio transmitter, that is lower power. Now they have regained communication they are trying to determine the cause on hardware that is nearly 50 years old. Any communication takes days. When you think you have a difficult issue to debug, spare a thought for this team.

The Ultimate in Debugging

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  • by lgordon ( 103004 ) <larry.gordon@III ... inus threevowels> on Wednesday November 13, 2024 @11:48AM (#64942771) Journal

    I used to work with outsourcing in India in the early 2000's, I think the communication with Voyager is probably faster.

    • I just had an issue with Veeam support to debug a veeam powershell command that couldn't be cancelled. That took them over 30 days to get me the solution.

  • by Waffle Iron ( 339739 ) on Wednesday November 13, 2024 @12:49PM (#64942957)

    No matter what, the first step to try while trying to remotely diagnose any problem is:

    "Unplug the power cord, then wait for 30 seconds. Then plug it back in and let us know if you still have the problem."

  • With such a long time between issuing a command and getting a response they have plenty of time to think and ponder how to proceed. That is an invaluable asset.
  • by Petersko ( 564140 ) on Wednesday November 13, 2024 @03:20PM (#64943439)

    When I read about the troubleshooting of voyager last year I was really impressed. The ability to relocate critical code around failed memory just lit up my nerd brain. After almost 25 years in critical systems support, reading this gave me deep respect for the designers.

    https://arstechnica.com/space/... [arstechnica.com]

    • by AmiMoJo ( 196126 )

      Relocating code around failed memory is a nice feature to have, but quite an old one. I remember back in the 90s there were Linux patches to support mapping out failed chunks of RAM, but it goes back much further than that in fact.

      It can be done in software if your code can be relocated. Basically you have to either have a CPU that supports long relative jumps, very small code, or a loader that copies the code somewhere and then fixes all the jump addresses. The last one has been around since the 1960s.

      You

      • True. The thing I was impressed by was the complete round trip. The ability to peek the memory to identify the failed blocks, redistribute the code into non-contiguous chunks, upload and write the new code, all through the antenna connection at such unbelievable distances.

        As you said, not new. But brilliantly done.

  • That’s nothing. They should try debugging the SPU vector processors on the PS3 CPU (Cell Broadband) using the horrendous Sony tools and the unmitigated binfire that was the SN Systems debugger.
  • This seems an opportune time to revisit a classic: Real Programmers Don't Use Pascal [ed.ac.uk]. It even mentions Voyager so apparently Real Programmers are alive and well.

Were there fewer fools, knaves would starve. - Anonymous

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