totm apr 2024 Voyager 1 in critical condition

[Minmus Taster]

Over the past few months the situation on the probe has gotten progressively worse. A glitch in one of the main processors of the craft prevent it from sending coherent telemetry back to earth. It can still recieve commands and execute them, it just can't communicate with us properly. Unfortunately since no good telemetry is coming through its nearly impossible to even diagnose what the problem even is, let alone if theres a work around. Many members of the current team running it don't seem to have much optimism in solving the issue. The current plan is to try and switch the computer to a mode that was used while it was preforming a flyby to try and at least isolate the problem. What do you reckon the odds of success are and could the probe have any use if it's science mission is ended by the issue?

[Shpaget]

While the end of its life is a loss for scientific comunity, and humanity as awhole, we should keep in mind that the original primary mission was supposed to last only five years. We got 40 years of extra science out of it.

In addition to this malfunction, the RTG is also at its last useful decays and very soon will no longer be able to produce enough power to sustain the probe anyway.

We should not mourn the loss, but celebrate its life and achievements.

Congratulations to the entire team that was involved in design, manufacture and operating it over the decades.

[darthgently]

6 hours ago, Shpaget said:

While the end of its life is a loss for scientific comunity, and humanity as awhole, we should keep in mind that the original primary mission was supposed to last only five years. We got 40 years of extra science out of it.

In addition to this malfunction, the RTG is also at its last useful decays and very soon will no longer be able to produce enough power to sustain the probe anyway.

We should not mourn the loss, but celebrate its life and achievements.

Congratulations to the entire team that was involved in design, manufacture and operating it over the decades.

Agreed.  However, at this point, there is a unique value in taking advantage of the unique engineering and signal processing challenge of just keeping in contact with Voyager-1.  If we can get useful data from the sensors or control it that would be a bonus.  That said, the budget could be cut some if the sole goal is to maintain contact and learn new techniques for doing that

[cubinator]

The science they manage to squeeze out of these things years and decades after the missions they were designed for is truly inspiring. Voyager is in a unique place for us, the farthest that we've ever touched, and it will be missed when it finally disappears into the void. I hope they can keep in touch with it for a few more years, before its final endless mission.

[darthgently]

If anything, Voyager-1 has made an extremely strong case that any future extra solar probes should have an RTG isotope with a  much longer halflife and more robust and redundant electronics and attitude control.  When is the next time the planets arrange for a similar daisy-chain slingshot?

[RKunze]

40 minutes ago, darthgently said:

If anything, Voyager-1 has made an extremely strong case that any future extra solar probes should have an RTG isotope with a  much longer halflife

The problem with that: Longer halflife means less decay, which means less energy from decay per kilogram of RTG, which means more mass to satisfy the energy budget. And "more mass" is not what you want on a deep space probe.

Besides, the PU-238 in the RTGs of the voyager probes is still putting out a respectable amount of energy. With an output of 2.4 kilowatt at launch, the three RTGs on board are still delivering more than one KW each (should be quite a bit more, but I'm too lazy to calculate the output after approximately one half of the half-life time). The problem: That is thermal power, not electrical. And the thermo elements that convert it to electrical energy never worked at more than 6.5% efficiency (the 6.5% was the efficiency at launch, and thermo converters don't get better after being in constant use in space for almost half a century). Which means over 90% of the raw RTG energy output is just waste heat.

 

[darthgently]

22 minutes ago, RKunze said:

The problem with that: Longer halflife means less decay, which means less energy from decay per kilogram of RTG, which means more mass to satisfy the energy budget. And "more mass" is not what you want on a deep space probe.

Besides, the PU-238 in the RTGs of the voyager probes is still putting out a respectable amount of energy. With an output of 2.4 kilowatt at launch, the three RTGs on board are still delivering more than one KW each (should be quite a bit more, but I'm too lazy to calculate the output after approximately one half of the half-life time). The problem: That is thermal power, not electrical. And the thermo elements that convert it to electrical energy never worked at more than 6.5% efficiency (the 6.5% was the efficiency at launch, and thermo converters don't get better after being in constant use in space for almost half a century). Which means over 90% of the raw RTG energy output is just waste heat.

 

I recall that some advanced PVs are getting good at converting IR in a separate layer, not sure if better than TCs though.  Heck, maybe that new layer is just a thermocouple, but I recall it is a real silicon PV junction

[mikegarrison]

11 hours ago, darthgently said:

Agreed.  However, at this point, there is a unique value in taking advantage of the unique engineering and signal processing challenge of just keeping in contact with Voyager-1.  If we can get useful data from the sensors or control it that would be a bonus.  That said, the budget could be cut some if the sole goal is to maintain contact and learn new techniques for doing that

I don't really see how solving this problem of keeping 1970s hardware and software alive remotely is going to have any direct applicability to new missions.

[darthgently]

37 minutes ago, mikegarrison said:

I don't really see how solving this problem of keeping 1970s hardware and software alive remotely is going to have any direct applicability to new missions.

I can see a signal processing challenge, sorry you can't

If we can track its position via radio direction finding we can possibly detect nearby unknown masses out there from how V1's orbit changes.  Occlusions in its signal could detect bodies out there.  Ya never know.  We got it out there, learn from it being there is all I'm saying

[mikegarrison]

2 hours ago, darthgently said:

If we can track its position via radio direction finding we can possibly detect nearby unknown masses out there from how V1's orbit changes.  Occlusions in its signal could detect bodies out there.  Ya never know.  We got it out there, learn from it being there is all I'm saying

That's not responding to what I said. Or perhaps I misunderstood you.

I am not disputing there is more information to be gained from Voyager 1. I was responding to the idea that it would be useful to learn new techniques for maintaining contact with 1970s probes. (The last part of the post I quoted.)

[kerbiloid]

1. They should keep keeping the contact at least to know, how large is the physical bubble of the Solar System reality, and if the probe will bounce off the wall, stick in it, or disappear and immediately reappear from the opposite direction, approaching to the Earth.

2. The longer it flies - the more chances that the aliens will intercept it and use for invasion.
So, the RTG should be replaced with reactor to explode in the end.

3. The Harry Potter fanfic by Yudkowski says, that one of these probes (idk, which one) is carrying another Voldemort's horcrux, so it's wise to keep keeping eye on it.

[Nuke]

how long will it be till new horizons is far enough out to take up interstellar space survey duty? in any case the solution is more outer solar system flybys are needed. MOAR! flyby all the things. 

Edited February 12 by Nuke

[Minmus Taster]

On 2/11/2024 at 7:06 AM, kerbiloid said:

3. The Harry Potter fanfic by Yudkowski says, that one of these probes (idk, which one) is carrying another Voldemort's horcrux, so it's wise to keep keeping eye on it.

Link please? 

5 hours ago, Nuke said:

how long will it be till new horizons is far enough out to take up interstellar space survey duty? in any case the solution is more outer solar system flybys are needed. MOAR! flyby all the things. 

New Horizons isn't arriving at the Heliopause for many years, probably the 2040's? The main issue with those kinds of missions are power and duration. There is a painful shortage of RTG's right now (I believe New Horizons used a spare Cassini generator) and it's hard to get funding for a mission that's going to last longer then a politicians time in office, let alone something that they may not actually get to see begin in their lifetimes. That's assuming that New Horizons will still be operating when it gets there, not sure if the generator it has is going to be good that long.

[mikegarrison]

49 minutes ago, Minmus Taster said:

There is a painful shortage of RTG's right now

Side effect of reducing nuclear weapons stockpiles and testing. No ready source of plutonium.

[kerbiloid]

On 2/12/2024 at 8:31 PM, Minmus Taster said:

Link please? 

https://hpmor.com/chapter/108

Oops, it was Pioneer.

But you never know about those warlocks. Better keep your eyes on Voyagers, too.

[Terwin]

On 2/9/2024 at 7:50 PM, mikegarrison said:

That's not responding to what I said. Or perhaps I misunderstood you.

I am not disputing there is more information to be gained from Voyager 1. I was responding to the idea that it would be useful to learn new techniques for maintaining contact with 1970s probes. (The last part of the post I quoted.)

Novel and extreme situations help us confirm and extend our understanding of the technologies involved.

As a theoretical example:

If a new technique is found for extracting useful data from a signal that would previously have been considered too close to the noise floor, then that technique might also be useful for reducing the required broadcast power for wireless networks or tools.  

Without the incentive of maintaining a connection to an old but still active historic probe in deep space, that technique might never have been found.

[Minmus Taster]

This has been known for a bit now but thought I should post this here:

https://www.space.com/nasa-voyager-1-communications-breakdown-solved

[darthgently]

1 hour ago, Minmus Taster said:

This has been known for a bit now but thought I should post this here:

https://www.space.com/nasa-voyager-1-communications-breakdown-solved

I wonder if there is a way to mark bad memory blocks the way hard drives mark bad blocks and avoid them.   Probably built in already in newer probes 

Edited April 11 by darthgently

[magnemoe]

16 minutes ago, darthgently said:

I wonder if there is a way to mark bad memory blocks the way hard drives mark bad blocks and avoid them.   Probably built in already in newer probes 

Think this has been part of disk management since the start at least early dos versions had this. 
More critical systems should have it much earlier. 
Still the ones who build this craft should get serious credit. 

[darthgently]

45 minutes ago, magnemoe said:

Think this has been part of disk management since the start at least early dos versions had this. 
More critical systems should have it much earlier. 
Still the ones who build this craft should get serious credit. 

Disks, yes, RAM, no.  As far as I know (which is nothing on this) Voyager 1 has bubble memory.  Time to rabbit hole...

Here is a great link I'm still reading through.  Not bubble mem, ha ha, IC RAM, from what I can tell, but no disk drive either.  Voyagers use tape for secondary storage.  And V1's tape is still working? Amazing!

https://www.allaboutcircuits.com/news/voyager-mission-anniversary-computers-command-data-attitude-control/

Edited April 11 by darthgently
Added link

[PakledHostage]

2 hours ago, darthgently said:

I wonder if there is a way to mark bad memory blocks the way hard drives mark bad blocks and avoid them.   Probably built in already in newer probes 

My understanding is that that's exactly what they're going to do. Just the "marking" will be done on the ground in new firmware that they're going to develop then upload.  They'll need to re-write the code to work around the bad memory. Shoehorning a fix like that into a '70s vintage processor won't be easy, but I am confident they'll manage...  Even if it means they have to make room by taking something of the original functionality out.

And thinking about it some more, it'd be a fascinating project to work on. I wonder what they have in the way of tools to develop and test on? Do they have a full ground reference system, or do they just have an emulator? Imagine a Voyager virtual machine running on some processor, deep in the bowels of the JPL campus somewhere!

[NFUN]

They've already had to disable most of the equipment because if power concerns. I'm sure they've got memory to spare

[StrandedonEarth]

18 minutes ago, NFUN said:

They've already had to disable most of the equipment because if power concerns. I'm sure they've got memory to spare

They certainly don't need camera software any more...

[darthgently]

1 hour ago, PakledHostage said:

My understanding is that that's exactly what they're going to do. Just the "marking" will be done on the ground in new firmware that they're going to develop then upload.  They'll need to re-write the code to work around the bad memory. Shoehorning a fix like that into a '70s vintage processor won't be easy, but I am confident they'll manage...  Even if it means they have to make room by taking something of the original functionality out.

And thinking about it some more, it'd be a fascinating project to work on. I wonder what they have in the way of tools to develop and test on? Do they have a full ground reference system, or do they just have an emulator? Imagine a Voyager virtual machine running on some processor, deep in the bowels of the JPL campus somewhere!

My first thought is make the bad section a data segment that an unused structure points to  which prevents any other var or structure getting allocated to that location.  But that may entail too much overhead in that highly constrained situation.  Will be interesting to see what they do

[Nuke]

4 hours ago, darthgently said:

Disks, yes, RAM, no.  As far as I know (which is nothing on this) Voyager 1 has bubble memory.  Time to rabbit hole...

Here is a great link I'm still reading through.  Not bubble mem, ha ha, IC RAM, from what I can tell, but no disk drive either.  Voyagers use tape for secondary storage.  And V1's tape is still working? Amazing!

https://www.allaboutcircuits.com/news/voyager-mission-anniversary-computers-command-data-attitude-control/

best tape decks in the known universe.

i think the real solution is to remap the tx buffer into an unused memory location. since there are a lot of systems you can no longer use due to lack of power, and other failures. if some of those have memory mapped i/o, you mighty be able to use that memory space for a new buffer.  while this is trivial to do in asm, there just isnt any hardware you can test and verify this earth side.