How NASA Repaired Voyager 1 from 15B Miles Away

https://arstechnica.com/space/2024/04/recoding-voyager-1-nasas-interstellar-explorer-is-finally-making-sense-again/

by thm • 2 years ago

155 56 2 years ago

6mian• 2 years ago

It's astonishing they managed to debug and fix this, given how old and how far away Voyager is. I wonder if currently created designs are so robust in terms of repairability. Obviously, everything is much higher-level now; is it possible to fall back to something like low-level, direct memory access communication if something in higher layers fails?

I'm glad to see so many senior engineers on the team; it must be an exciting lifelong journey to work on the mission.

Wowfunhappy2• 2 years ago

Obviously, everything is much higher-level now; is it possible to fall back to something like low-level, direct memory access communication if something in higher layers fails?

I have a feeling that code for NASA spacecrafts is not so high-level, for a reason.

davedx• 2 years ago

From what I understand current flight control systems are still written in relatively low level languages like C++, with extremely careful memory management strategies.

luc_• 2 years ago

Yes, C++ may even be too far. Writing C in a very regimented way to run on very old processors by today's standards is 'aerospace grade (tm)'.

seydor2• 2 years ago

Let's not be overly pessimistic. Even today's phones have a low-level debug backdoor. I imagine Voyager3 with today's tech would provide much more interesting data, but it's a matter of time, who wants to wait another 50 years

adezxc2• 2 years ago

I'm in awe that it's maintainable even though it launched almost 50 years ago, while there is software deployed right now that won't be maintainable in the next 5 years.

sealeck• 2 years ago

Because it makes economic sense to apply extremely rigorous standards when writing software for a space probe, but not for a web app for expense reclaims?

TacticalCoder• 2 years ago

Or maybe because we are, literally, talking about rocket scientists?

resource_waste2• 2 years ago

Perks of direct control over your systems.

When you inherit some random security update to an obscure library and it causes things to break, you were never expected to understand that edge-case.

However, if you spin up your own safety critical embedded system, you should be able to follow the logic completely.

Different costs. One is in the billions of dollars, one is in the hundreds of thousands of dollars.

adezxc2• 2 years ago

True, yet I feel the expectation regarding software has shifted from expecting much better quality even 10-15 years ago to things we have now, where nobody is surprised about web apps crashing your browser etc.

TomMasz• 2 years ago

I totally lack the patience to be able to deal with sending a command and having to wait 2 days to see the result. Everything about this is awe-inspiring for me.

robertlagrant• 2 years ago

Imagine opening Vim and gradually typing the commands in to edit a file with a 2-day time lag. Only at the end to notice the fateful words at the bottom of the editor: [read-only].

Faaak• 2 years ago

This reads like a great opening to a geek-sci-fi book!

_flux• 2 years ago

I wonder if you could teach millions of terminal sessions to an LLM and then have mosh run the inference algorithm to hide the latency (and eventually correct when it gets the real data)..

lostlogin2• 2 years ago

Imagine opening Vim

Imagine being able to close Vim.

And yes, I’m hopeless. Nano please.

marban• 2 years ago

Don't get into GenAI then.

FerretFred• 2 years ago

It sounds like my old company (not NASA) when we submitted tickets to offshore tech support - 2 days response time was the norm, and sometimes we never got a response back at all...

peterburkimsher• 2 years ago

I told my dad about the Voyager fix, and he said that back in the days of punched cards, latency of 2 days was quite normal! He was still impressed at the high stakes of the repair though, with no option to go over and turn it off and on again.

epgui3• 2 years ago

This is basically why I quit cancer research to go into software. It was like trying to debug via the postal service. You do something to your cell cultures, and you only find out 6 weeks later if something went wrong.

And because a million different things can happen to cells over the course of 6 weeks, you don't get a line number, or a stack trace, or very much debugging information at all.

remoquete• 2 years ago

So you quit potentially life-saving research because you couldn't open a terminal session to a cell culture? Why did you even enter that field in the first place? Genuine question.

Kailhus• 2 years ago

How about actually hooking them up to a computer? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4490468/

bregma2• 2 years ago

My computer course in high school has a one week turnaround time. Send your punched card deck off Thursday of one week, get the printout back the next Thursday.

Two days would have been luxury.

lostlogin2• 2 years ago

When you say ‘has a one week turnaround’ you mean ‘had’ don’t you?

If not, I’d quite like to try a course on punchcard usage.

Poudlardo• 2 years ago

111001111011110010000011000111101111110111111101100

lebuffon• 2 years ago

2 BASE ! ok

111001111011110010000011000111101111110111111101100 ok

CONSTANT X ok

ok

HEX X U. 18F7EFEC ok

DECIMAL X U. 418901996 ok

8 BASE ! X U. 3075767754 ok ok

I give up. What does this number represent?

Wowfunhappy2• 2 years ago

I interpreted it as an answer to the question "How NASA repaired Voyager 1 from 15 Billion Miles Away." Ie they did it with ones and zeros.

jebarker• 2 years ago

Due to its age, Voyager doesn't have any ground simulators

Has anyone attempted to build this? Assuming the documentation is available

rvnx2• 2 years ago

The doc is on paper, not properly organized, and the people who wrote it are mostly dead: https://www.wired.com/story/nasa-voyager-one-space-probe-los...

So they test in production, and they see what happens.

It's a really cool job they have (I'm not sarcastic), life-balance at NASA is known to be great ( = low to no pressure ) + since it's publicly funded, no clients, no profit to make, and if politics ask for feedback, you can claim anything and they can't verify it, and you can play with tech that others don't have the chance to see.

crispyambulance• 2 years ago

  > It's a really cool job they have (I'm not sarcastic), life-balance at NASA is known to be great ( = low to no pressure ) + since it's publicly funded, no clients, no profit to make [...]

I've known some NASA folks and they would not describe it as "low to no pressure". It's highly bureaucratic, constantly under budget pressure, and contractors get much of the cool work.

Don't know about voyager, but I expect that many of those folks have been there decades-- like a closed society. I am sure it's awesome for them, more power to them, but it's certainly not the norm.

xbmcuser• 2 years ago

It hit me just now that most of the people that designed programmed and launched this satellite are already dead

persnickety• 2 years ago

This sounds like a miscommunication. They probably don't have a simulator for the entire device, but attempting to fix the software without having an emulator of the computer would be downright irresponsible.

pxmpxm• 2 years ago

Exactly what I was thinking - it's virtually guaranteed they've spent the effort to build a software emulation solution.

Vagantem• 2 years ago

Would anyone be able to hack Voyager? Just wondering - if the software is that old, as long as you can get a signal to it anyone should be able to hack it / wipe it right?

Is the biggest barrier the enormous satellite dish you'd need to contact it or do the commands have a auth header with some key you'd need to brute force?

rcxdude• 2 years ago

I think the big radio telescope is the main barrier. At this point there's only one in the world with enough transmit power to talk to it, and a handful that can receive the signal.

perihelions• 2 years ago

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

(pdf) https://deepspace.jpl.nasa.gov/files/820-100-H.pdf

70 meter antenna, 80 kW X-band transmit power (122 dBW EIRP)

thunderbong• 2 years ago

I posted a Reddit link earlier asking the same question [0]

HN thread [1]

[0] https://old.reddit.com/r/explainlikeimfive/comments/1cbhvwg/...

[1] https://news.ycombinator.com/item?id=40141836

mavili3• 2 years ago

So they essentially repaired 'hardware' from 22 light hours away, that's just insane! I love engineering.

hrunt• 2 years ago

22.5 light HOURS. Imagine pressing a button on your old desktop calculator and waiting 2 days for the number to show up.

mavili3• 2 years ago

Oh yes I did mean hours but incorrectly typed minutes. Corrected

mavili3• 2 years ago

Not knowing that IF it would indeed show up! Although the benefit here is that after the 45 hours they would know if it's ever coming back, as opposed to having to keep waiting.

hooby• 2 years ago

nasa@earth:~$ ping voyager.1

PING voyager.1 (###.###.###.###) 56(84) bytes of data.

64 bytes from voyager.1 (###.###.###.###): icmp_seq=1 ttl=inf time=44.8 hrs

64 bytes from voyager.1 (###.###.###.###): icmp_seq=2 ttl=inf time=45.1 hrs

64 bytes from voyager.1 (###.###.###.###): icmp_seq=3 ttl=inf time=44.9 hrs

64 bytes from voyager.1 (###.###.###.###): icmp_seq=4 ttl=inf time=45.2 hrs

64 bytes from voyager.1 (###.###.###.###): icmp_seq=5 ttl=inf time=45.0 hrs

seydor2• 2 years ago

IPv4 didnt even exist when it was launched. They should have waited for ipv6

dirkc• 2 years ago

Something very wrong is going on with voyager, your terrestrial network or the universe!!! The spread of that ping is 0.4 hrs which I take to be 24 minutes! During that time a radio signal would travel 3 times the distance between the sun and the earth (AU). The only thing I can think of that could possibly be causing that delay is having to wait for a deep space network dish to aim properly.

dpcx• 2 years ago

Something I always wonder about when Voyager has these issues is this: how long would it take for a probe launched today to catch up to Voyager? I assume there are better engines now, better capability for payload launch, better fuels, etc. I then wonder how long it would take to get that probe ready to be launched assuming that it was given the green light.

bregma2• 2 years ago

Most of the Voyager acceleration was done by using gravity assist ("slingshot flybys" -- effectively falling toward a large mass like Jupiter and missing). As far as I know gravity has not improved or become better since the 1970s.

consp• 2 years ago

Though calculations about gravity assists have improved and the knowledge about the application as well.

sfn42• 2 years ago

It's a bit more complicated than falling and missing. Getting out of the gravity well takes the same amount of energy as you gain from falling into it, so those two things alone would be pointless.

I'm not an astrophysicist but I think you have to do it in such a way that you "steal" some of the planet's orbital momentum.

probably_wrong• 2 years ago

This exact question has been tackled by Randall Munroe in his "What If?" section:

https://what-if.xkcd.com/38/

Barely related, but on the same spirit, I recommend Kafka's short story "The city coat of arms" for his perspective on the "there are better engines" line of reasoning:

https://www.babelmatrix.org/works/de/Kafka%2C_Franz-1883/Das...

ChrisArchitect• 2 years ago

[dupe]

How NASA Repaired Voyager 1 from 15B Miles Away

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