7 ms·

The Brains of the Voyager Spacecraft: Command, Data, and Attitude Control (2017)

94 points by dddddaviddddd 7y ago

mitchtbaum 7y ago
any friend who keeps in touch no matter how far away they get is a friend worth keeping https://en.wikipedia.org/wiki/Radio_drama https://en.wikipedia.org/wiki/Radio_drama
walrus01 7y ago
> "The Voyager FDS would be the first spaceflight computer to use CMOS volatile memory. This was a big step since it was a fairly new technology and, if power was lost to the ICs for a moment, all memory would be lost, too. However, a direct line from the radioisotope generators, which provided direct current, was used to ensure the CMOS ICs would never lose power unless something happened to the generators. It was decided that, if something had happened to the generators that rendered them inoperable, there would unlikely be a need for the FDS, anyway." Sort of like having a PCI-Express bus RAM drive card full of DDR4 DIMMs, in a computer that'll never be powered off, because it has the most ridiculously protected N+1 power supply and UPS system imaginable. Since there's a single RTG per craft, and failure of the RTG would very quickly kill the entire craft due to lack of power and extremely cold temperatures, seems totally logical.
deleted 7y ago
[deleted]
dddddaviddddd 7y ago
I read this after seeing this submission earlier today: https://news.ycombinator.com/item?id=21285793 https://news.ycombinator.com/item?id=21285793
keyle 7y ago
It's incredible, today we can't keep a bunch of apps running in virtualized containers in virtual machines in some data centre across the world... But these two little things are still chugging along on the outskirts of our solar system in the harsh conditions of space.
- aloknnikhil 7y ago
  I don't get such comparisons. The voyager had a single purpose - to travel through space. It was purpose built for that and that alone. Things were simple. Definitely an engineering marvel for that time. Between now and then, we've had reusable rockets, multiple landers, developing nations launch rockets at a tiny cost of the original project. Things have improved. Let's compare that. Data-centers serve billions of people and have significantly more challenges in maintaining SLAs. It's not a trivial problem to solve.
  - eru 7y ago
    They serve billions of people and serve them cheaply!
- SmellyGeekBoy 7y ago
  You only need to look at the reliability of cars built in the 1970s compared to today to realise that not everything has gone backwards.
sandworm101 7y ago
One day the voyagers will be gone from our perception. I'm not happy about that. We need something else chasing them into the dark. We should send another. It doesn't need to be a massively complex craft. Slap a big antenna and some RTGs onto a satellite bus. Then an ion engine as a slow boost stage and launch the package. Do a lap or two between earth and mars to build up speed, then aim for Jupiter. Science is great, but having that candle out there should be reason enough.
- nine_k 7y ago
  I wonder if the technology has advanced enough to make this feasible for a (large enough) private org. Maybe not exactly for a kickstarter campaign, but for a group of wealthy sponsors who would donate several dozen millions each. The cost of the space launch went down dramatically. Many components are standardized and thus less expensive. CAD systems allow a much smaller number of engineers to design the custom parts. New materials, like maybe carbon fiber, could help make the thing lighter weight. Computing the orbital mechanics with great precision is within capabilities of a laptop. This seems to be just on the brink.of achievable.
  - dylan604 7y ago
    Has anyone reached to S R Hadden to see if he's willing to chip in? I think sending a satellite in the direction of Vega might be of his interest.
    - joezydeco 7y ago
      Yeah he died a few months ago but nobody is supposed to know about that yet.
  - 2rsf 7y ago
    that's very close to what SpaceIL did, sending a privately funded craft to the moon https://en.wikipedia.org/wiki/SpaceIL https://en.wikipedia.org/wiki/SpaceIL
  - planteen 7y ago
ngcc_hk 7y ago
Luckily it was v1/2. Not v6 that leads to Star Trek the first movie. Lost the memory might lose the mission - to collect all info and return to the creator.
hliyan 7y ago
I was actually more impressed by one of the references of the article than the article itself: https://history.nasa.gov/computers/Ch6-2.html https://history.nasa.gov/computers/Ch6-2.html Did not know history.nasa.gov existed...

94 points by dddddaviddddd 7y ago

any friend who keeps in touch no matter how far away they get is a friend worth keeping https://en.wikipedia.org/wiki/Radio_drama https://en.wikipedia.org/wiki/Radio_drama

walrus01 7y ago

> "The Voyager FDS would be the first spaceflight computer to use CMOS volatile memory. This was a big step since it was a fairly new technology and, if power was lost to the ICs for a moment, all memory would be lost, too. However, a direct line from the radioisotope generators, which provided direct current, was used to ensure the CMOS ICs would never lose power unless something happened to the generators. It was decided that, if something had happened to the generators that rendered them inoperable, there would unlikely be a need for the FDS, anyway." Sort of like having a PCI-Express bus RAM drive card full of DDR4 DIMMs, in a computer that'll never be powered off, because it has the most ridiculously protected N+1 power supply and UPS system imaginable. Since there's a single RTG per craft, and failure of the RTG would very quickly kill the entire craft due to lack of power and extremely cold temperatures, seems totally logical.

deleted 7y ago

[deleted]

dddddaviddddd 7y ago

I read this after seeing this submission earlier today: https://news.ycombinator.com/item?id=21285793 https://news.ycombinator.com/item?id=21285793

keyle 7y ago

It's incredible, today we can't keep a bunch of apps running in virtualized containers in virtual machines in some data centre across the world... But these two little things are still chugging along on the outskirts of our solar system in the harsh conditions of space.

aloknnikhil 7y ago
I don't get such comparisons. The voyager had a single purpose - to travel through space. It was purpose built for that and that alone. Things were simple. Definitely an engineering marvel for that time. Between now and then, we've had reusable rockets, multiple landers, developing nations launch rockets at a tiny cost of the original project. Things have improved. Let's compare that. Data-centers serve billions of people and have significantly more challenges in maintaining SLAs. It's not a trivial problem to solve.
- eru 7y ago
  They serve billions of people and serve them cheaply!
SmellyGeekBoy 7y ago
You only need to look at the reliability of cars built in the 1970s compared to today to realise that not everything has gone backwards.

sandworm101 7y ago

One day the voyagers will be gone from our perception. I'm not happy about that. We need something else chasing them into the dark. We should send another. It doesn't need to be a massively complex craft. Slap a big antenna and some RTGs onto a satellite bus. Then an ion engine as a slow boost stage and launch the package. Do a lap or two between earth and mars to build up speed, then aim for Jupiter. Science is great, but having that candle out there should be reason enough.

nine_k 7y ago
I wonder if the technology has advanced enough to make this feasible for a (large enough) private org. Maybe not exactly for a kickstarter campaign, but for a group of wealthy sponsors who would donate several dozen millions each. The cost of the space launch went down dramatically. Many components are standardized and thus less expensive. CAD systems allow a much smaller number of engineers to design the custom parts. New materials, like maybe carbon fiber, could help make the thing lighter weight. Computing the orbital mechanics with great precision is within capabilities of a laptop. This seems to be just on the brink.of achievable.
- dylan604 7y ago
  Has anyone reached to S R Hadden to see if he's willing to chip in? I think sending a satellite in the direction of Vega might be of his interest.
  - joezydeco 7y ago
    Yeah he died a few months ago but nobody is supposed to know about that yet.
- 2rsf 7y ago
  that's very close to what SpaceIL did, sending a privately funded craft to the moon https://en.wikipedia.org/wiki/SpaceIL https://en.wikipedia.org/wiki/SpaceIL
- planteen 7y ago

ngcc_hk 7y ago

Luckily it was v1/2. Not v6 that leads to Star Trek the first movie. Lost the memory might lose the mission - to collect all info and return to the creator.

hliyan 7y ago

I was actually more impressed by one of the references of the article than the article itself: https://history.nasa.gov/computers/Ch6-2.html https://history.nasa.gov/computers/Ch6-2.html Did not know history.nasa.gov existed...