Not to gloat, but my Dad worked on Voyager. Not gonna lie, I'm pretty proud of that fact.
VeeJer lives.
Pretty freaking amazing in so many ways. Forty-six years after launch, this thing is still operational. What's it using for power? How can it send a radio signal across 15 billion miles of space? How can we detect that signal? The thing was launched in 1977, and it still works!
Thank goodness we got Voyager back. If only the Pioneers still worked as well, then we could actually start to map the heliopause.
In reply to 1988RedT2 :
RTGs- Radiothermal isotropic generators. Using the Seebeck effect, hot plutonium against cold vacuum produces a flow of electrons for power. Thermoelectric generators are cheap and semi-common (Think of those fans for old wood stoves that have to be on the hot side to work) but their efficiency is literally single-digit. I think Voyager is working off of ~40 watts at this point.
It can send and recieve radio because of a maneuver it did in 2004 and that massive dish antenna.
Gibberish or a language we don't know after being hacked on-site?
In reply to 1988RedT2 :
It's powered by a RITEG (which only has a year or two left until the radiation source is depleted too far to power it), it has a big well-aimed dish, on Earth we're using many really freakin' huge and well-aimed dishes with fancy high-powered equipment on them...
It's not really back yet, they just managed to get a core dump almost by accident. But that's the first step to figuring out how to work around the problem.
If you haven't watched "it's quieter in the twilight", that's a great documentary about the team keeping these relics alive. I think they're expecting to be too low on power to function in 2030, with Voyager 2 likely to fail first because it's colder for some reason. The two craft are out of backups and a bunch of the sensors have been turned off to save power.
It should get to about a light-day out from Earth around the 50th anniversary, which is spectacular.
1988RedT2 said:The thing was launched in 1977, and it still works!
That was the last year before they made them put catalytic converters on those things.
In reply to Woody (Forum Supportum) :
It's got a NASA motor, a radioisotope thermoelectric generator plant, it's got NASA radios, NASA sensors, NASA telemetry. It's a model made before catalytic converters so it'll run good on regular gas. What do you say, is it the new Voyager or what?
In reply to Appleseed :
They traded the last one for a microphone...
I saw Voyager launch. On TV.
I saw Veejer on TV, also. 
The team managed to reprogram Voyager and it's now sending back engineering data!
There's a chunk of corrupted memory, so they had to move a bunch of code into new memory locations around without breaking anything - not an easy task, and you only get one shot at it. There was no single piece of memory big enough so it had to be split into pieces. They sent the commands on Thursday and had to wait until Saturday to see if it worked.
Next is to do the same with science data.
In reply to Keith Tanner :
That is some steelie-eyed missile man E36 M3.
In reply to Keith Tanner :
It's too bad that modern coders don't have to be that careful with the code they write- especially for size.
But it's pretty astronomical that they got it going again. They don't have too many more years until the Pt battery is going to run out.
Yeah, it only has a few years left before it won't have enough power left to transmit. But there is nothing out where it is, and it's sending back some really interesting data. I'm really hoping for a 50th birthday party.
Modern coders working with microcontrollers do have to be a little more efficient with their code than most, so it's not a completely dead art to optimize for speed and memory on a constrained device. The Voyager team is working with some really thorny stuff in assembly, though.
Imagine trying to try to reprogram something with this much lag time:
It takes 22 1/2 hours to send a signal to Voyager 1, more than 15 billion miles (24 billion kilometers) away in interstellar space. The signal travel time is double that for a round trip.
Did they power cycle the unit?
Keith Tanner said:Yeah, it only has a few years left before it won't have enough power left to transmit. But there is nothing out where it is, and it's sending back some really interesting data. I'm really hoping for a 50th birthday party.
Modern coders working with microcontrollers do have to be a little more efficient with their code than most, so it's not a completely dead art to optimize for speed and memory on a constrained device. The Voyager team is working with some really thorny stuff in assembly, though.
If it was actually nothing out there, this would not be a big deal at all... LOL. There's so much more than expected.
As for coding, partially disagree. It's better than autocode, without a doubt. But it's still a lot less of a stress than what I started working on up through the EECV. Those had some really tight memory constraints that made coding a real art (and easy to read). But even for those, that coding does not make it main stream- and that's the part I think really sucks now. Computers could be so much faster with old school coding.
One other thing that's real art in this- the NASA team has had to make a real model to design all the code around. Of a partially worn out almost 50 year old space craft. With, as you point out, assembly code. This team is really special.
Sorry, there's nothing else out there of ours, so this is the only data we'll get for a long, long time. Well, other than Voyager 2. There's apparently a really interesting pressure wave that was unexpected.
I agree that coding for performance may not be a priority when cycles are so cheap, but I'm currently trying to run a full dashboard on an RP2040 chip and that's proving to be a bit of a challenge without any visible lag occasionally. It's enough to prevent me from getting lazy :) And when you're building massive applications that run on cloud hardware where you pay for time, a small improvement in performance can have big returns. Google's homepage used to be a great example of this, it was so pared down. The middle ground - a home PC or a PCM - is where you can get lazy because it's not that expensive to just throw resources at the problem.
Im not sure if it's been mentioned, but "It's quieter in the twilight" is a great documentary on the Voyager team. I think it's on Prime.
Whatever percentage of my tax dollars are going to NASA and the rest of the space program, it aint enough and If I could tell the IRS to send all my dough that way, I would. The ROI here is off the charts. Look at the record..
Voyagers, Spirit and Opportunity, Ingenuity, and so many others that had, like, 90 day planned lifespans and were still sending useful data years and years later. I love it, so so so much.
FYI, there's a really good technical article from the 2016 International Conference on Space Operations outlining the challenges of working with Voyager.
https://arc.aiaa.org/doi/epdf/10.2514/6.2016-2415
There's quite a bit about power management, but here's something from the start of that section:
...RTG decay, currently about 4 Watts (W) per year. The total power output for V1 is 252 W and V2 is 254 W as the writing of this paper. It requires about 200 W for V1 and about 198 W for V2 to operate the spacecraft without any science instruments
So V1 (Voyager 1) will likely run out of useful power around 2029 and V2 about a year later, even if nothing else goes wrong.
Keith Tanner said:Sorry, there's nothing else out there of ours, so this is the only data we'll get for a long, long time. Well, other than Voyager 2. There's apparently a really interesting pressure wave that was unexpected.
I agree that coding for performance may not be a priority when cycles are so cheap, but I'm currently trying to run a full dashboard on an RP2040 chip and that's proving to be a bit of a challenge without any visible lag occasionally. It's enough to prevent me from getting lazy :) And when you're building massive applications that run on cloud hardware where you pay for time, a small improvement in performance can have big returns. Google's homepage used to be a great example of this, it was so pared down. The middle ground - a home PC or a PCM - is where you can get lazy because it's not that expensive to just throw resources at the problem.
Im not sure if it's been mentioned, but "It's quieter in the twilight" is a great documentary on the Voyager team. I think it's on Prime.
It absolutely is a priority.
In reply to z31maniac :
Maybe it should be, but getting product out the door might trump it when there's no real downside to chewing up a little more processor or memory. I'm thinking of consumer-grade software. Heck, I'm thinking of a custom application we use for middleware - it loads up an immense amount of data just to show a status screen. IIRC it's about 5 MB. It could easily be flat HTML, but instead it's pulling in all sorts of javascript libraries and other resources because that was the easiest option and hey, bandwidth and memory is cheap.
Keith Tanner said:Im not sure if it's been mentioned, but "It's quieter in the twilight" is a great documentary on the Voyager team. I think it's on Prime.
Just saw this last night. Well worth the watch, thanks for the heads up.
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