"So somewhere out there in interstellar space beyond the boundary of the Solar System is a card frame full of 74 logic that’s been quietly keeping an eye on a star since the early 1970s, and the engineers from those far-off days at JPL are about to save the bacon of the current generation at NASA with their work. We hope that there are some old guys in Pasadena right now with a spring in their step."
https://hackaday.com/2023/07/31/just-how-is-voyager-2-going-to-sort-out-its-dish-then/
Posts
I was wondering how long it took a radio signal to get to Voyager 2. I won't post that, but this is what Wikipedia say's about the current problem.
ReplyDelete-------------------------------------
Voyager 2 was lost when flight control pointed its antenna away from Earth, moving it by 2%. The NASA dish antenna in Canberra is being used to search for the space probe and will be used to saturate Voyager 2's location with commands to re-align the probe's antenna in an attempt to re-establish the radio link. If NASA fails to contact the probe it is expected that an automatic system on Voyager 2 will direct its dish towards Earth in October 2023.
-----------------------------------------
Trevor, I had to find it, and I blame you
ReplyDeletehttps://voyager.jpl.nasa.gov/mission/status/
This comment has been removed by the author.
ReplyDeleteThe NASA report mentioned in the Hack-a-day post shows 74Lxx logic on the schematics, NASA probably wouldn't have had time to space qualify 74LSxx logic - also 74LS is Low-power Schottky logic which is bipolar not CMOS. from an old QA component engineer :)
ReplyDeleteTrue, Chuck! The 50-some years are addling my noddle :)
ReplyDeleteI'd later suspected it would be 74HCxx, the CMOS variant. All were prior to the large-scale integration that heralded the first microprocessors. The current drain of straight 74xx, the earlier TTL hardware, would be excessive, though possibly more robust against radiation.
My earliest foray in the Digital world was to build the monitor console (remote at Ashburton's South Canterbury Electric Power Board office) for our (NZ's) major Hydro-power scheme at Lake Benmore. That was 74xx logic, essentially counting the pulses sent from the plant, translating to Nixie displays of frequency, "We're generating X kilo/Mega Watts right now!"
Dex -
ReplyDeleteThe neat thing is that Pioneer's circuits are still working after 50 years - according to the wiki the whole shebang runs on 400 watts from nuclear generators. And they can disable parts of the spacecraft if they don't have enough power.
This is from the Canberra Times where one of NASA's deep space network antennas is.
ReplyDelete---------------------------------
NASA's Voyager 2 spacecraft is back chatting it up after flight controllers corrected a mistake that had led to weeks of silence.
Hurtling ever deeper into interstellar space billions of kilometres away, Voyager 2
stopped communicating two weeks ago. Controllers sent the wrong command to the 46-year-old spacecraft and tilted its antenna away from Earth.
On Wednesday, NASA's Deep Space Network sent a new command in hopes of re-pointing the antenna, using the highest powered transmitter at the huge radio dish antenna in Australia. Voyager 2's antenna needed to be shifted a mere two per cent.
It took more than 18 hours for the command to reach Voyager 2 - more than 19 billion kilometres away - and another 18 hours to hear back.
The long shot paid off. On Friday, the spacecraft started returning data again, according to officials at California's Jet Propulsion Laboratory.
The space-qualified QPL was limited back then. So with a launch date of Sept 1977, and dialing back to its program design time frame, not sure which 74Lxx or LSxx chips where "on the list" yet. Construction methods were also different from typical "card frames". Lots of hermetic flatpacks on exotic substrates for survivability. We did it different then.
DeleteOh frabjous day! Calloo! Callay!
ReplyDelete