For the frames which can't be decoded with confidence due to the SNR being too low, I assume that if a couple of bits of the frame data were known, that would enable the rest of the frame to be decoded.

Since the data appears very similar between frames, it seems easy to select some bits which are highly likely to be constant, enabling the whole of the rest of the frame to be decoded...

Certainly the format is documented at NASA. Could someone obtain a copy with a FOIA request?

Maybe just send an email. If someone has the data and a moment, they might send it, and NASA seems to encourage an engaged public.

Exactly. But surely someone has done this already? What are we missing here?

(I think the data format for one of the early landers, Viking perhaps, was lost, but didn't someone figure it out?)

Which project was it that found the old tapes and reversed how to get that data? I seem to remember them being in an old fast food building or something. It is however entirely possible I'm confusing stories together.???

You are probably thinking of the Lunar Orbiter Image Recovery Project (LOIRP) that was housed in an old McDonalds

https://moonviews.com

I believe the same people were involved in the ISEE-3 Reboot Project

https://sservi.nasa.gov/articles/isee-3-reboot-project/

Yes, the McMoons location is what I was thinking. Thanks for helping ensure that I'm not crazy. at least in this particular instance! So this time, the voices were not leading me astray ;-)

This seems to have some more clues: https://www.liquisearch.com/voyager_program/telemetry

Although searching for the formats mostly yields copies of the same text on different websites

i remember an article, maybe on arstechnica maybe a decade ago about a group of enthusiasts who had found some old satellite computer at a home. they looked it up and found it belonged to some old satellite nasa had forgotten about so they asked for permission to try to contact it and eventually they did get it to run a booster after decades. Don't know what it was but this sounds like that somewhat

You're thinking of the ISEE-3 reboot project: https://en.wikipedia.org/wiki/International_Cometary_Explore...

and what do you know... http://spacecollege.org/isee3/isee-3-is-in-safe-mode.html

links to https://www.spacecraftforall.com/ which is now a vpn site

oh sweet. this is nice. yeah

https://arstechnica.com/science/2014/05/nasa-hands-space-ent...

this is probably the exact one. well not quite a decade but it is close

>> At the beginning the output is around zero because the loops haven’t locked yet.

They could run the PLL on the signal backwards. This would provide lock at the beginning. Combining that phase measurement with the forward one might also reduce phase error in general.

Cool! It even show the bits! Now, what do they mean? What are the fields? What science/instrument data was gathered?

"Other than finding a few binary counters and observing the general structure of the frames, I haven’t been able to figure out the meaning of any of this data."

Feels a bit like failing to communicate with an alien race.

This made me sad after the obscene amount of work put into decoding the radio signal into a binary format.

Is this because the specs for the data aren't published? But wait, NASA is a public body, so these specs should be out there. Or is it because the spec is lost to time?

We are still getting science data from both Voyagers. So somebody somewhere has code to decode the bits.

Is it hard to ask NASA people how to decode these bits?

Asking shouldn't be hard. (And I would start at the DSN people at JPL). But the answer might be "well, we have that binary. I think it was written in $deadlanguage. But I have never seen the source, don't know who wrote it and I don't know how the decode works". Or they might have a binder full of documentation on paper. Who knows.

Given what I know about the JPL's engineering process, they probably have a binder full of a few hundred pages of documentation archived somewhere.