6 ms·

that is amazing for something 14.5 billion miles away

tomxor 5y ago
It's also amazing considering it's using a computer built over 45 years ago from discrete components with only 70Kb of memory, while operating on a gradually failing thermonuclear power source. Voyager 1 also holds the world record for the longest continual operation of a computer: https://www.guinnessworldrecords.com/world-records/635980-longest-period-of-continual-operation-for-a-computer https://www.guinnessworldrecords.com/world-records/635980-lo...
- dTal 5y ago
  Wow. World record for the longest continual operation of a computer... achieved in a radiation bath.
  - tomxor 5y ago
    Pretty much, although I think the RTG is mounted on a limb as far away from the other equipment as possible, but still the computer needs to be able to tolerate a decent amount of radiation. It also has an interesting redundant design where it has double the component count and can either exploit that for extra compute or redundancy in case of component failure.
    - anthropodie 5y ago
      I think parent comment is talking about cosmic radiation and not the one from RTG which most probably is properly shielded.
      - tomxor 5y ago
        Possibly. I wonder which is the more significant source given it's distance from the Sun.
        mgdlbp 5y ago
        Solar particles become less of a threat, but the sun's atmosphere actually shields the solar system from some types of cosmic rays. Don't know what proportion of electronics faults stem from each, though.
  - monocasa 5y ago
    It used a memory called "plated wire memory" which, like the very related core memory is very resistant to changes caused by radiation. https://en.wikipedia.org/wiki/Plated_wire_memory https://en.wikipedia.org/wiki/Plated_wire_memory
- admiral33 5y ago
  What an incredible project. Does anyone know of any good interviews or written content from the engineers?
  - ProAm 5y ago
    There are tons of documentaries and interviews. [1] [2] https://www.pbs.org/the-farthest/ https://www.pbs.org/the-farthest/
- ge96 5y ago
  > ...the last of the project's original programmers, retired, and it was difficult to find a replacement with such in-depth knowledge of what now seem like ancient hardware and design principles Man I would not want to be the one to brick that.
  - exikyut 5y ago
    That makes me realize, it would actually be an incredibly fun job to be in the team that manages the simulation/emulation stack that people tinker with to learn about this thing. Going on a lot of presumption here (and a bit of optimism...), I would presume "don't brick it" is backed up by an appropriate level of funding to cover the training people receive before they get to touch production. In an optimal scenario (don't be wrong... don't be wrong...) this would cover component-level electrically-accurate (because radiation) logic simulation that everything gets tested on first.
    - Breza 5y ago
      NASA doesn't mess around with simulators. I've read accounts from astronauts and ground controllers where they say their actual missions feel anticlimactic after all the insane things they had to do in the simulators. Gene Kranz managed to crash a simulated Apollo mission into a mountain.
- gurjeet 5y ago
  The code on the computers has been upgraded, and even the language used to prpgram has changed over the years [1]. Which leads me to believe that the computer has been restarted/rebooted many times in all these years. I think there may be other computers, right here on Earth, that may be able to at least compete given those criteria. [1]: From the linked page: > The CCS originally ran software written in the Fortran programming language, but this has been continually upgraded since its launch (software updates can be transmitted and installed remotely). The current software is written in a mixture of C and Fortran. The following is fascinating. > The age of the computer and its codebase has caused problems for NASA in recent years. In 2015 Larry Zottarelli, the last of the project's original programmers, retired, and it was difficult to find a replacement with such in-depth knowledge of what now seem like ancient hardware and design principles.
benbristow 5y ago
I wonder what the ping/latency is...
- tomxor 5y ago
  (Current) One-Way Light Time = 21:35:13 [0] So 43 hours 10 minutes 26 seconds minimum, excluding processing time. That's probably another record... Although I'm pretty sure it can't process ICMPs, so "ping" in the more general sense. [0] https://voyager.jpl.nasa.gov/mission/status/ https://voyager.jpl.nasa.gov/mission/status/
  - benbristow 5y ago
    That must be fun over SSH/Telnet. 43 hours between every key press Joking, but thanks for the interesting info (and Frost1x also).
    - _joel 5y ago
      Come on, SSH and Telnet? That's ludicrous. It's a job for https://mosh.org/ https://mosh.org/
      - rzzzt 5y ago
        At the very least, local echo must be enabled.
  - tanbogy 5y ago
    And I used to get angry with 250ms ping playing WoW.
  - mrb 5y ago
    Neither ICMP nor IPv4 existed when the Voyager probes were launched in 1977 :) ICMP was created in 1981
    - tomxor 5y ago
      Yeah, that's what I was implying ;D I think an older probe also took the first digital pictures before bitmap images were a thing, they could digitise it at the probe end but had to colour in the pixels on a piece of paper at the other end if I recall correctly. Point is, NASA had to solve a lot of digital communication problems long before they had established terrestrial solutions or before computers were even capable of solving the whole problem on their own. Then again, even if the timing was reversed, a lot of terrestrial communication protocols have no chance of working properly at the ranges required for space exploration - something I've been meaning to look into is the redundancy requirements over those long distances, since re-transmission is so costly in terms of latency that it probably makes sense to pack as much redundancy into the signal as possible, we already do this with terrestrial communication in the form of various codes, but there's a finer balance between increased bandwidth and the relatively low latency cost of re-transmission in the case of unrecoverable sequences... I'm guessing you want a far lower probability of loss for a 43 hour round trip.
iszomer 5y ago
What's more amazing is how NASA's Deep Space Network continues to make communication with Voyager possible. https://www.nasa.gov/feature/jpl/nasa-contacts-voyager-2-using-upgraded-deep-space-network-dish https://www.nasa.gov/feature/jpl/nasa-contacts-voyager-2-usi...

It's also amazing considering it's using a computer built over 45 years ago from discrete components with only 70Kb of memory, while operating on a gradually failing thermonuclear power source. Voyager 1 also holds the world record for the longest continual operation of a computer: https://www.guinnessworldrecords.com/world-records/635980-longest-period-of-continual-operation-for-a-computer https://www.guinnessworldrecords.com/world-records/635980-lo...

dTal 5y ago
Wow. World record for the longest continual operation of a computer... achieved in a radiation bath.
- tomxor 5y ago
  Pretty much, although I think the RTG is mounted on a limb as far away from the other equipment as possible, but still the computer needs to be able to tolerate a decent amount of radiation. It also has an interesting redundant design where it has double the component count and can either exploit that for extra compute or redundancy in case of component failure.
  - anthropodie 5y ago
    I think parent comment is talking about cosmic radiation and not the one from RTG which most probably is properly shielded.
    - tomxor 5y ago
      Possibly. I wonder which is the more significant source given it's distance from the Sun.
      - mgdlbp 5y ago
        Solar particles become less of a threat, but the sun's atmosphere actually shields the solar system from some types of cosmic rays. Don't know what proportion of electronics faults stem from each, though.
- monocasa 5y ago
  It used a memory called "plated wire memory" which, like the very related core memory is very resistant to changes caused by radiation. https://en.wikipedia.org/wiki/Plated_wire_memory https://en.wikipedia.org/wiki/Plated_wire_memory
admiral33 5y ago
What an incredible project. Does anyone know of any good interviews or written content from the engineers?
- ProAm 5y ago
  There are tons of documentaries and interviews. [1] [2] https://www.pbs.org/the-farthest/ https://www.pbs.org/the-farthest/
ge96 5y ago
> ...the last of the project's original programmers, retired, and it was difficult to find a replacement with such in-depth knowledge of what now seem like ancient hardware and design principles Man I would not want to be the one to brick that.
- exikyut 5y ago
  That makes me realize, it would actually be an incredibly fun job to be in the team that manages the simulation/emulation stack that people tinker with to learn about this thing. Going on a lot of presumption here (and a bit of optimism...), I would presume "don't brick it" is backed up by an appropriate level of funding to cover the training people receive before they get to touch production. In an optimal scenario (don't be wrong... don't be wrong...) this would cover component-level electrically-accurate (because radiation) logic simulation that everything gets tested on first.
  - Breza 5y ago
    NASA doesn't mess around with simulators. I've read accounts from astronauts and ground controllers where they say their actual missions feel anticlimactic after all the insane things they had to do in the simulators. Gene Kranz managed to crash a simulated Apollo mission into a mountain.
gurjeet 5y ago
The code on the computers has been upgraded, and even the language used to prpgram has changed over the years [1]. Which leads me to believe that the computer has been restarted/rebooted many times in all these years. I think there may be other computers, right here on Earth, that may be able to at least compete given those criteria. [1]: From the linked page: > The CCS originally ran software written in the Fortran programming language, but this has been continually upgraded since its launch (software updates can be transmitted and installed remotely). The current software is written in a mixture of C and Fortran. The following is fascinating. > The age of the computer and its codebase has caused problems for NASA in recent years. In 2015 Larry Zottarelli, the last of the project's original programmers, retired, and it was difficult to find a replacement with such in-depth knowledge of what now seem like ancient hardware and design principles.

benbristow 5y ago

I wonder what the ping/latency is...

tomxor 5y ago
(Current) One-Way Light Time = 21:35:13 [0] So 43 hours 10 minutes 26 seconds minimum, excluding processing time. That's probably another record... Although I'm pretty sure it can't process ICMPs, so "ping" in the more general sense. [0] https://voyager.jpl.nasa.gov/mission/status/ https://voyager.jpl.nasa.gov/mission/status/
- benbristow 5y ago
  That must be fun over SSH/Telnet. 43 hours between every key press Joking, but thanks for the interesting info (and Frost1x also).
  - _joel 5y ago
    Come on, SSH and Telnet? That's ludicrous. It's a job for https://mosh.org/ https://mosh.org/
    - rzzzt 5y ago
      At the very least, local echo must be enabled.
- tanbogy 5y ago
  And I used to get angry with 250ms ping playing WoW.
- mrb 5y ago
  Neither ICMP nor IPv4 existed when the Voyager probes were launched in 1977 :) ICMP was created in 1981
  - tomxor 5y ago
    Yeah, that's what I was implying ;D I think an older probe also took the first digital pictures before bitmap images were a thing, they could digitise it at the probe end but had to colour in the pixels on a piece of paper at the other end if I recall correctly. Point is, NASA had to solve a lot of digital communication problems long before they had established terrestrial solutions or before computers were even capable of solving the whole problem on their own. Then again, even if the timing was reversed, a lot of terrestrial communication protocols have no chance of working properly at the ranges required for space exploration - something I've been meaning to look into is the redundancy requirements over those long distances, since re-transmission is so costly in terms of latency that it probably makes sense to pack as much redundancy into the signal as possible, we already do this with terrestrial communication in the form of various codes, but there's a finer balance between increased bandwidth and the relatively low latency cost of re-transmission in the case of unrecoverable sequences... I'm guessing you want a far lower probability of loss for a 43 hour round trip.

iszomer 5y ago

What's more amazing is how NASA's Deep Space Network continues to make communication with Voyager possible. https://www.nasa.gov/feature/jpl/nasa-contacts-voyager-2-using-upgraded-deep-space-network-dish https://www.nasa.gov/feature/jpl/nasa-contacts-voyager-2-usi...