More Voyager instruments shut down to eke out power supplies More science instruments are being shut down on the Voyager probes as engineers attempt to eke out the power and keep them running for years to come. It should not come as a surprise that NASA is turning off instruments. The shutdowns were already planned to take place as the venerable probes enter the final years of their …
Not a Voyager scientist so can't speak authoritatively, but one issue I could see here would be that every change/switch/command increases the likelihood of a fault condition arising; much like a lightbulb will burn more or less forever as long as you don't keep turning it off and on.
In that sense it's probably a deliberate decision to have instruments either permanently on, or permanently off.
This post has been deleted by its author
The worst thing you can do to electronics is to turn them on. The second worst thing is to turn them off again.
So whilst I don't know for sure, I would hazard that they'd probably avoid cycling instruments in case it caused a more terminal fault. Or they powered one down, and the other then didn't power back up, and then the one that was working fine also wouldn't come back, and we lose a working instrument.
They appear instead to be splitting the load between Voyager 1 & 2, so they've knocked off the Voyager 1 CRS, but Voyager 2's is still on, whilst Voyager 2's LECP is getting shut off but Voyager 1's is still going.
Whilst they're both in quite different parts of the sky (V1 above the orbital plane, V2 below), given that we're basically measuring interstellar radiation out there, the data from each probe is probably quite interchangeable (they're not that far outside the solar system), so shutting down instruments in a different order is likely safer (provided power budget allows - one isn't notably higher draw than the other).
It's also that they're shutting down the less useful ones (or broken ones). So the cameras have long since been turned off (Pale Blue Dot being the last one taken) because there is naff all to see out there with a camera. Some of the instruments aren't working properly anymore either, or of limited value (the plasma flow detector stopped working on one, and didn't work well on another due to its orientation)
I felt so sad in January when an applicaiton I wrote 14 years ago had to be turned off for good. It'd been running faultlessly for 14 years, probably the most reliable and useful thing I've ever made. But I felt so proud of it though at the same time.
Then I remember Voyager, and if I'm happy over an app lasting 14 years I couldn't imagine what it would feel to be one of the people behind it knowing how long and how well they've lasted.
A beer each for all of them.
I can claim 27 years for code that I know is still running in critical systems (and is still in long term support for 3 years!)
I can claim writing patches for 26 year old OS code and new drivers for a 24 year old version where the hardware has finally had to be replaced.
I can claim 36 years for things running at the Museum of Computing.
What no "grey beard" icon?
My achievement is 33 years, probably got a few more and hopefully take me to retirement.
Ancient looking and DOS-based, bugs largely beaten out of it 30 years ago, just keeps going under dosemu as that allows direct hardware access if you configure it so...
I feel you. I once wrote a Certificate dispensing system for the previous company I work for. I also set up an SFTP server for a project. Boss was proud of it, I was proud of it,
But the head IT manager. Wanted everything moved to Sharepoint. Project was shut down two or three years before I was laid off, and they kept me kicked upstairs all that time before finally letting me go.
"Deep respect to the guys who made them and those still keeping them going."
Those groups are mostly the same people, here is the team after fixing the software last year:
https://d2pn8kiwq2w21t.cloudfront.net/original_images/e1-PIA26275-voyager-copy-16.jpg
Those groups are mostly the same people,
The 1970s were a distressingly long time ago now...
Most of the people in that photo are not in their 80s (which they would have to be if they were a 20-something fresh-faced grad in the early 1970s when mission planning started)!
Many of them have of course spent much of their career on the mission, but joined it post-launch (though I don't doubt there are a few senior engineers in their 80/90s still on speed-dial if they need some consultancy!).
They don't write code like they used to. When I were a lad things were meant to last. It was also a simpler time without the many unpredictable layers we have to deal with now. It is very impressive that it's still churning away. Especially when you consider space radiation can really mess stuff up. Just how did they account for that in the code?
"They don't write code like they used to"
Yes they do. The filter of time applied: 99% of everything is garbage and the old stuff you see today is merely what survived longest
One example is victorian housing. The stuff that people point as as "built to last" was specifically built to much higher standards than were normal, mainly for use as low cost housing. The old and ornate piles (mansions) you see have a LOT of issues and need huge amounts of money invested to keep them falling down because for the most part they weren't meant to stand more than 50 years (one place I worked in had the entire back wall bowing by over a foot (3 floors) out due to the builders cutting corners in the 1870s and needed work to keep it standing which would have been more than a new BUILDING)
The classic extreme example is the Brighton Pavilion. It's eggshell fragile due to the cheap and cheerful method of construction but shows the adage that the richer people are, the less they tend to care about longevity (See: Luxury Cars)
You have a very valid point. I never thought of it like that. In my work career I've seen VBA that's been in action 20-30 years and is still running. It's had a few iterations but still. As for architecture and house building the 1940-60's semi-detached houses are still going strong as are a lot of the post war housing stock. I guess back then we decided not to cut corners for every single penny of profit. I make no comment on the state of Barratt and Wimpy homes as it is not required.
Wimpey were actually decent until the mid 70s - I live on a close where the majority of the houses are 1970-72 vintage Wimpey and when I bought mine, the local surveyor I used told me they virtually never found any serious faults with them, unless the house had been totally neglected by its current owner. It may be a brick box but it's a light and airy one with bedroom dimensions new builds can only dream of.
It's a fair bet it was designed to be tolerant. Speculating [before researching], it possibly uses "rope memory" for ROM, and magnetic cores for RAM (note, see article, "plated wire memory", similar). The logic might be TTL (article confirms), like the older minicomputers. This stuff would be pretty tolerant of voltage spikes caused by EM radiation. Any large scale integration is probably on sapphire substrate. They used to do that for satellites, maybe still do.
I found https://hackaday.com/2024/05/06/the-computers-of-voyager/ which explains things. 2 of the 3 computers are like that.
The article also describes the flight data system as having CMOS RAM, DMA capability, and CMOS logic. I would guess that this is why the (somewhat) recent failure happened, as CMOS would be more susceptible to radiation than TTL.
I have a Volvo XC40 which has had so many system faults that I suspect its electronics are sensitive to gnats farting a mile away. At least the collision avoidance is, because it trips randomly for no apparent reason so I am totally in awe of engineers who can design a system that is still going despite being almost my age.
It's probably less grumpy too.
I remember seeing the launch of both Voyagers on TV as a teenager at school. I followed every planetary flyby in the National Geographic Magazine. Amazing that the better part of a human lifetime these probes have been speeding through space, collecting loads of data.
I will (again) raise a glass to the team behind this amazing achievement.
"If we don't turn off an instrument on each Voyager now, they would probably have only a few more months of power before we would need to declare end of mission."
These things are powered by RTGs right? And the decay rate of the plutonium therein isn't going to change based on the amount of power being drawn from it, is it? It's not like a battery; the plutonium generates an amount of heat purely based on its decay rate, and the available heat is turned into electricity by thermoelectric converters. So what's actually running out here that's going to last longer if they turn off this instrument? Is it that they wouldn't be able to draw enough current to prevent critical systems from permanently freezing or something?
This post has been deleted by its author
"And the decay rate of the plutonium... isn't going to change "
That depends on what you mean by decay rate. The half life doesn't change but that does mean there's less and less power over time so load needs to be trimmed to what's available. If it isn't then something - and quite possibly all of it, will go TITSUP. (Terminally Insufficient Power Upsets Probe)
if, at the last gasp, just keeping the comms link up would be useful when there is only enough energy for that? No sensors, just a forlorn bleeping at the edge of the solar system to tell us they are still there? Like the retreating bagpiper at a funeral walking off into silence.
I feel strangely sad at this point.
Bloody hell, man... that went into Spirit territory. How can one feel sad for a chunk of metal millions of miles away?
So, do they keep running the most important sensors that happens to be the most power hungry, or the most irrelevant but lowest power sensor, that will ensure the best longevity?
I wonder how they weight it down and decide the shutdown sequence.
==================
On the other hand, I was hoping for a Voyager 6 and a wormhole / blackhole...
with modern tech it might be time to send a better probe, flying a LOT faster, out into the Oort cloud to study those outer planetoids as well as the "edge of the solar system" on it's way to the nearest star. Ion thrusters (and maybe solar sail tech) could get it out into deep space, and 50 years from now, who know WHAT we'd be finding...
There's not going to be much flying a lot faster. This took advantage of a once every 175 years "grand tour" gravity assist from Jupiter, Saturn, Uranus, and Neptune to get their current speed.
Solar sail tech is not going to help at this distance from the sun, and ion thrusters would have the same power issues that the probes are currently experiencing.
These probes (and others that are heading out) blow my mind.
The golden records could be viable for 5 billion years.
"Depending on their luck with this dust, the Voyagers may be able to ride out trillions of trillions of trillions of years, long enough to cruise through a truly alien cosmos, Oberg said."
Interesting read on the deep future of the probes - https://www.space.com/predicting-voyager-golden-records-distant-future
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2025
