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

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

allaboutcircuits.com

94 pointsdddddaviddddd17 comments

> "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.

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.

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.

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.

Yeah he died a few months ago but nobody is supposed to know about that yet.

that's very close to what SpaceIL did, sending a privately funded craft to the moon

https://en.wikipedia.org/wiki/SpaceIL

B612 has been trying to do this for a long time, but is not yet successful. Their mission is to defend Earth against asteroid threads, starting with a telescope to detect them.

https://en.wikipedia.org/wiki/B612_Foundation

You have basically described the New Horizons space probe tha investigated Pluto & is cutrently investigating the Kuiper belt. :) Well, minus the ion engine, it has just generic hydrazine monopropelant trusters for course corrections.

The only reason we can still communicate with them is because we're using massive ground based dish arrays to boost the transmissions and amplify the received signal. It's likely any follow-up craft with dishes any smaller and less power hungry wouldn't be able to communicate with the Voyagers at all.

Found it - from the article: "While any one of the antennas is more than powerful enough to transmit to Voyager, a single 34-meter antenna does not collect enough electromagnetic radiation to detect Voyagers downlink"

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.

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.

They serve billions of people and serve them cheaply!

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.

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

Did not know history.nasa.gov existed...

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

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.

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

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