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I'm amazed that they're able to disable a voltage regulator remotely. Did they just build in relays for every single component in case they wanted to rewire eve

by evan_ 3y ago

I'm amazed that they're able to disable a voltage regulator remotely. Did they just build in relays for every single component in case they wanted to rewire everything on the fly or was this something they specifically knew they might want to do 45 years ago?

sgtnoodle 3y ago
Yeah, I'd say it's actually pretty common to make spacecraft avionics as remotely switchable as possible. For one thing, there's likely to be a considerable amount of redundancy so that a single component failure doesn't ruin your whole mission. It's good practice to have a way to isolate any component that is anticipated to fail. FDIR is a known acronym: fault detection, isolation and recovery.
CodeWriter23 3y ago
They probably implemented fail-safe relays with circuitry to disengage automatically under hazardous conditions but also controlled remotely.
foobarian 3y ago
Also I assume there isn't a web service running there with a "enable/disable" endpoint to control stuff. Wonder what the control stack looks like. Turned up this from https://voyager.gsfc.nasa.gov/Library/DeepCommo_Chapter3--141029.pdf https://voyager.gsfc.nasa.gov/Library/DeepCommo_Chapter3--14...: > The signal consists of 16-bps, Manchesterencoded commands, biphase modulated onto a squarewave subcarrier frequency of 512 hertz (Hz). There are references to fuller descriptions of the command set but I haven't found them yet.
- stouset 3y ago
  I can't help but wonder how possible it would be (or would have been at some point in the past) for a person with evil intent to send unauthorized commands to these probes. How are signals authenticated? At this point, is it just that there are only a handful of parties capable of sending a strong enough radio signal to a precise-enough location in space, and who know the position of these probes to the degree of accuracy required?
  - jutrewag 3y ago
    [dead]
  - jacquesm 3y ago
    You'll need to hack NASA's deep space network first I think. On your own and with a normal mortal's budget you're not going to be able to do much of anything.
    - stouset 3y ago
      Nowadays sure. What about shortly after launch? Say you’re the USSR and want to quietly piss in NASA’s cornflakes. Or hell, say you’re Putin—today—and want to do the same thing. Could you?
      - kadoban 3y ago
        Shortly after launch it was almost certainly not known how communication worked. And if you had a spy that could get you that info, you could just get them to press the wrong button(s) instead.
      - Red_Leaves_Flyy 3y ago
        Got a Time Machine?
      - midoridensha 3y ago
        Putin has limited resources. He'd rather spend them on his stupid war, and also building other weapons and warships, rather than a giant radio antenna and a team of engineers trying to hack a 45-year-old spacecraft's communications protocol, just to screw with NASA.
        stouset 3y ago
        I’m asking about the technical measures used to authenticate commands to these probes. The bit about Putin was just about framing the question.
squarefoot 3y ago
This could be as simple as disconnecting a zener diode from ground, but yeah, I'd be a lot interested in knowing more technical details.
- deleted 3y ago
  [deleted]
iancmceachern 3y ago
Exactly, and to have the foresight so long ago to architect it this way, brilliant.

by evan_ 3y ago

sgtnoodle 3y ago

Yeah, I'd say it's actually pretty common to make spacecraft avionics as remotely switchable as possible. For one thing, there's likely to be a considerable amount of redundancy so that a single component failure doesn't ruin your whole mission. It's good practice to have a way to isolate any component that is anticipated to fail. FDIR is a known acronym: fault detection, isolation and recovery.

CodeWriter23 3y ago

They probably implemented fail-safe relays with circuitry to disengage automatically under hazardous conditions but also controlled remotely.

foobarian 3y ago

Also I assume there isn't a web service running there with a "enable/disable" endpoint to control stuff. Wonder what the control stack looks like. Turned up this from https://voyager.gsfc.nasa.gov/Library/DeepCommo_Chapter3--141029.pdf https://voyager.gsfc.nasa.gov/Library/DeepCommo_Chapter3--14...: > The signal consists of 16-bps, Manchesterencoded commands, biphase modulated onto a squarewave subcarrier frequency of 512 hertz (Hz). There are references to fuller descriptions of the command set but I haven't found them yet.

stouset 3y ago
I can't help but wonder how possible it would be (or would have been at some point in the past) for a person with evil intent to send unauthorized commands to these probes. How are signals authenticated? At this point, is it just that there are only a handful of parties capable of sending a strong enough radio signal to a precise-enough location in space, and who know the position of these probes to the degree of accuracy required?
- jutrewag 3y ago
  [dead]
- jacquesm 3y ago
  You'll need to hack NASA's deep space network first I think. On your own and with a normal mortal's budget you're not going to be able to do much of anything.
  - stouset 3y ago
    Nowadays sure. What about shortly after launch? Say you’re the USSR and want to quietly piss in NASA’s cornflakes. Or hell, say you’re Putin—today—and want to do the same thing. Could you?
    - kadoban 3y ago
      Shortly after launch it was almost certainly not known how communication worked. And if you had a spy that could get you that info, you could just get them to press the wrong button(s) instead.
    - Red_Leaves_Flyy 3y ago
      Got a Time Machine?
    - midoridensha 3y ago
      Putin has limited resources. He'd rather spend them on his stupid war, and also building other weapons and warships, rather than a giant radio antenna and a team of engineers trying to hack a 45-year-old spacecraft's communications protocol, just to screw with NASA.
      - stouset 3y ago
        I’m asking about the technical measures used to authenticate commands to these probes. The bit about Putin was just about framing the question.

squarefoot 3y ago

This could be as simple as disconnecting a zener diode from ground, but yeah, I'd be a lot interested in knowing more technical details.

deleted 3y ago
[deleted]

iancmceachern 3y ago

Exactly, and to have the foresight so long ago to architect it this way, brilliant.