this post was submitted on 22 Apr 2024
561 points (99.0% liked)

science

14671 readers
231 users here now

just science related topics. please contribute

note: clickbait sources/headlines aren't liked generally. I've posted crap sources and later deleted or edit to improve after complaints. whoops, sry

Rule 1) Be kind.

lemmy.world rules: https://mastodon.world/about

I don't screen everything, lrn2scroll

founded 1 year ago
MODERATORS
 

Voyager 1 contact restored

all 39 comments
sorted by: hot top controversial new old
[–] [email protected] 47 points 6 months ago

That is truly amazing.

[–] [email protected] 35 points 6 months ago (2 children)

I was hoping they would say in this article what they did to fix it!

[–] [email protected] 104 points 6 months ago (6 children)

The actual news release has a bit more information.

The team discovered that a single chip responsible for storing a portion of the FDS memory — including some of the FDS computer’s software code — isn’t working. The loss of that code rendered the science and engineering data unusable. Unable to repair the chip, the team decided to place the affected code elsewhere in the FDS memory. But no single location is large enough to hold the section of code in its entirety.

So they devised a plan to divide the affected code into sections and store those sections in different places in the FDS. To make this plan work, they also needed to adjust those code sections to ensure, for example, that they all still function as a whole. Any references to the location of that code in other parts of the FDS memory needed to be updated as well.

Source: https://www.jpl.nasa.gov/news/nasas-voyager-1-resumes-sending-engineering-updates-to-earth

[–] [email protected] 23 points 6 months ago

That's incredible. It also reminds me of the episode of Star Trek Deep Space 9 where they need to find space to store a bunch of people's transporter patterns, so they just dump them into the stations computer, replacing everything that used to be there lol

[–] [email protected] 20 points 6 months ago (1 children)
[–] [email protected] 5 points 6 months ago

It interesting that the memory is so discrete that it can be reprogrammed when a single ROM fails. And it’s really neat that they made the whole thing accessible to a radio controlled boot loader. The planning that went into building and maintaining Voyager is really incredible.

I wonder if we could still build one as robust these days?

[–] [email protected] 14 points 6 months ago (4 children)

Wait how did they do all that WITHOUT contact?

[–] [email protected] 34 points 6 months ago (1 children)

The problem was that Voyager sent junk data back to us due to a memory fault. It was still responsive to receive updates from Earth and to pings.

Pinging Voyager 1 takes about 2 days, so testing updates is naturally quite slow.

[–] [email protected] 20 points 6 months ago

Not only round trip time, the hardware only supports bandwidth of 160bps at this range. Down from the 21.6kbps at launch.

[–] [email protected] 15 points 6 months ago* (last edited 6 months ago)

Im guessing it could still listen just not talk back

Edit read the article

Although the radio signal from the spacecraft had never ceased its connection to ground control operators on Earth during the computer problem, that signal had not carried any usable data since

[–] [email protected] 5 points 6 months ago

It's simple rocket science

[–] [email protected] 1 points 6 months ago

This Satelite must offer option to install software updates over the air, so they modified software and slowly uploaded it to the satelite.

[–] [email protected] 11 points 6 months ago (1 children)

rust programmers couldn't imagine the memory hacks smh

[–] [email protected] 11 points 6 months ago (1 children)

I know that this is supposed to be a joke, and I do find it funny, but I also find it sad that it carries a large dose of truth. C is such a "low-level" high-level language that it makes you deal directly with memory allocation and management as well as pointer arithmetic to advance addresses in the stack, which in my opinion is very important for programmers to gain an understanding of the actual hardware and architecture their programs are running on, because I feel that many don't have that understanding. Should Rust replace C in many applications, especially low-level, I fear that we will ultimately end up with worse code because of that. (BTW I know that Voyager's program is not written in C, this is just purely about your statement on Rust.)

[–] [email protected] 8 points 6 months ago

C will never fully go away.

Constrained environments will always remain in C.

But RUST offers the best trade off today. It is way better than C++.

C IMO is not comparable to RUST.

[–] [email protected] 7 points 6 months ago* (last edited 6 months ago)

Can we appreciate how they can basically change software of this 45y/o satelite over the air? Original designers thought everything through

[–] [email protected] 3 points 6 months ago

That was awesome!

[–] [email protected] 8 points 6 months ago (1 children)

They just kept wiggling the coat hanger until the signal cleared up

[–] [email protected] 3 points 6 months ago

It was much more complicated than that.

They also had to wrap half a roll of tin foil around the antennas.

[–] [email protected] 19 points 6 months ago (1 children)

Very cool, especially that the expertise still exists within NASA to understand and debug almost 50 year old code from a now ancient seeming architecture. They are probably training their people assigned to the Voyager mission in these things.

[–] [email protected] 9 points 6 months ago

They should hire people who are still making homebrew games for old consoles.

[–] [email protected] 18 points 6 months ago
[–] [email protected] 14 points 6 months ago (1 children)

Was thinking that it might come to be that we lose the ability before Vger does.

[–] [email protected] 13 points 6 months ago

this is just plain ol' awesome

[–] [email protected] 13 points 6 months ago (1 children)

Amazing. Sad That the 47000 curios of plutonio 238 in the RTG will be depleted by 2025 :(

[–] [email protected] 3 points 6 months ago (2 children)

Is it a fixed number or just estimate? I'd like to keep my hope up if possible.

[–] [email protected] 14 points 6 months ago (1 children)

Radioactive materials have a half-life, which means every X number of days/months/years, the material will have decayed to half its initial size. This continually happens, so while something might start at say 100g and have a 10 day half life, 10 days later it is 50g, 10 days later 25g, 10 days later 12.5g, 10 days later 6.25g, etc. This will continue forever until there is literally one atom left, at which point it is random chance when the atom would decay.

Voyager launched with 3 Radioisotope Thermoelectric Generators, each with 4.5kg of Pu238 which generated 157 watts of usable electric power at launch, for a total of 471 watts

It will be half that in 87.7 years (235W) . And half that (117W) in another 87.7.

The problem comes from the amount of power necessary to run the craft and it's radio. While the generators might continue to run for practically forever, at some point they just don't produce enough power to keep everything working. Its official mission is expected to end in 2025, but it's generators are expected to be able to power it's instruments for another ~10 years

[–] [email protected] 4 points 6 months ago

Just a reminder that half-life is a probabilistic measurement, not an exact one. Given adequate scale of material it’s accurate across the measured sample, but it is not precise at lower volumes of material or in narrower measurement periods.

[–] [email protected] 3 points 6 months ago

Estmate , around 2025. It depends on so many tings I guess , they are constantly doing enhancements to it since the beginning and that could make it last a little bit longer, but not much more I think.

[–] [email protected] 10 points 6 months ago

This is GREAT news.

[–] [email protected] 7 points 6 months ago (1 children)

Well alright, but if memory serves, it's Voyager 6 we have to be worried about.

[–] [email protected] 3 points 6 months ago (1 children)
[–] [email protected] 6 points 6 months ago (2 children)
[–] [email protected] 3 points 6 months ago

I should have known it was star trek lmao

[–] [email protected] 2 points 6 months ago (2 children)

I'm now sad to learn we only did Voyager 1 & 2.:(

[–] [email protected] 3 points 6 months ago

Lessons from the future were clearly learned.

[–] [email protected] 1 points 6 months ago

Only so far, there's still time.

[–] [email protected] 4 points 6 months ago

Thank the whales!