And it doesn't help that some missions manage their own archives differently, and there's a lot of terminology to learn on your own. One of the complete opposites of that, which was a joy, was the New Horizons archive which, at one point, you could download from a torrent! For example, if you wanted to see V3 of the Arrokoth encounter from 2019, you'd go to: https://pdssbn.astro.umd.edu/holdings/nh-a-lorri-3-kem1-v3.0...
Again, New Horizons is a bit of a rare case in which they went for super accessible data for everyone. PDS itself is a great system, but many missions will just upload a bit of data to PDS and then manage the rest some other way (Cassini for example has only a couple of instruments on PDS, and you have to go to some other URL if you want uncalibrated but automatically processed images on JPEG format[0], but yet another place (to which I've lost the link to and I can't find on mobile) for the full, science-grade dataset).
A great resource is OPUS[1] too, however I find it's UI a bit difficult, and in the end I prefer to download full datasets and just explore them on my own rather than going with those online browsers. For example, if you wanted to check the Voyager images of Neptune, you'd go to this massive URL[2]. Quick tip: once you've configured the filter you want to apply, the Search button is on the top left -- this is the kind of usability thing I mentioned, buttons and links aren't quite where you'd expect them. Oh and there's a limit to how many things you can select for download at once. And it's all dynamically loaded, and on and on and on. Which is why, as I said before, I generally prefer to just download the full GB sized dataset and explore it on my own.
[0] https://solarsystem.nasa.gov/raw-images/raw-image-viewer/?or...
[1] https://opus.pds-rings.seti.org/opus/
[2] https://opus.pds-rings.seti.org/opus/#/instrument=Voyager+IS...
I thought that was the case, but it's been so long since I've been on a mission proper (Cassini, student co-op) that I didn't want to say so without basis. Thanks!
As I'm just "playing" with the files, I don't mind waiting a few months/years to get access to full "scientific grade" readings from incredible complex machines and systems. And if the "raw" data is not easily available, they also usually do provide processed images as part of the missions public outreach campaigns (usually the ones that are found on Wikipedia).
The mission-specific parameters ("managed parameters") used by any given mission are usually more tightly controlled, as are the payload specifications for each telemetry channel.
> This is just telemetry data which doesn’t have much general or scientific interest
My understanding is that "telemetry" and "telecommand" stand for the downlink and uplink directions of a space link. I mostly worked upstream of telecommand, but I understood "telemetry" to refer to received data of any kind -- e.g. in CCSDS 130.1-G-3, an informational report on the design of the CCSDS telemetry system. https://public.ccsds.org/Pubs/130x1g3.pdf
By the by, I've been continually impressed with the quality of the CCSDS' documents. The "green books" (informational reports, like the one above) are extremely approachable and well-written.