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Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

smithsonianmag.com

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Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#101

Post by emchammer »

jdthedisciple wrote: post #95
jonplackett wrote: post #17

Were engineers 50 years ago just much smarter than we are now? It’s pretty unbelievable that these things still work. Or is there something systemic about how they were able to achieve so much so long ago with basically no computers to help.

They weren't affected by DEI nonsense yet.

It's not nonsense. Many of the radio receiver setups made use of diversity or dual-diversity configurations. Also, transmitter and receiver blocks from different manufacturers were wired in switchable primary/backup configurations.

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#102

Post by ReptileMan »

jonplackett wrote: post #17

Were engineers 50 years ago just much smarter than we are now? It’s pretty unbelievable that these things still work. Or is there something systemic about how they were able to achieve so much so long ago with basically no computers to help.

>Were engineers 50 years ago just much smarter than we are now?

Were the 2006 sony santa monica programmers smarter then us when they delivered God of War 2 for the PS2 on its tiny resources?

Usually the constraints force you to become inventive and smart. Put a hard limit of 128 mb per tab on web browsers and suddenly both the developers of the browsers and the web developers will become extremely smart.

The over abundance of resources has made the majority of software engineers lazy. If we once again live in scarcity times - suddenly people will start to ask why we need 8 abstraction layers to do something.

I would guess they were quite smart bunch, but no superhuman - just people tasked with extremely challenging task, trying to jury rig something on the edge of possibility. My guess is that they took their tasks more seriously and to heart.

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#103

Post by wffurr »

jordanb wrote: post #43
ghoomketu wrote: post #35

It's fascinating how Voyager 1, despite my lack of space knowledge, utilizes a nuclear power source for 40+ years, offering steady and reliable power without any moving parts that could degrade over time. In contrast, India's decision to rely on solar panels led vikram lander to be dead in just 14 days due to lack of sunlight (afaik). I'm curious about the rationale behind this choice when nuclear power seems like a…

A good reason is the lack of availability of the needed isotope (Pu238). The Europa Clipper has a huge array of solar panels instead of an RTG due to the last of the available supply going into the New Horizons spacecraft. Pu238 was a cast-off isotope from nuclear weapons development so it was more readily available during the cold war. We should be happy that it's scarce now. Also solar panels have gotten a lot bett…

There was just an article about a whole array of “nuclear batteries” using all sorts of decent chemistry: https://news.ycombinator.com/item?id=42118306

Are any of those candidates or are they just too small or with too poor a mass ratio compared to plutonium RTGs?

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#104

Post by heresie-dabord »

yodon wrote: post #77
jfengel wrote: post #33

Earlier quoted context omitted.

That doesn't seem helpful. Nothing lasts forever, and if you don't figure out when it's going to fail, it's going to be sooner rather than later.

>Nothing lasts forever, and if you don't figure out when it's going to fail, it's going to be sooner rather than later. You might be surprised about the reality of the situation. I had a professor who worked on the design and fabrication of the Apollo Guidance Computers, which likely was a somewhat similar process to the one being discussed here. It's been quite a few years since his lecture on it, but the process we…

A testament to requirements and quality. Thanks for sharing this insight, cheers!

> This is what happens when you have the best minds committed to designing systems that don't fail.

Given how times have changed, perhaps it is also valuable to note that other major-yet-unwritten factor: confidence in the supply chain.

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#105

Post by bigiain »

kibwen wrote: post #67
pupppet wrote: post #13

I didn’t realize the Voyagers relied on a once in a 175 year planetary alignment. What a lucky break technology had advanced to the point we could make use of it.

It wasn't just a lucky break, it was the result of furious efforts by scientists to lobby years in advance to take advantage of the alignment, as well as engineers who repurposed two Mariner probes to save money, as well as canny NASA bureaucrats who sneakily downplayed the possibility of a full Grand Tour in order to reduce estimated costs (with the full intent to underpromise and overdeliver, which Voyager 2 succes…

Still a huge amount of luck involved. If that planetary alignment had happened even 10 years earlier NASA probably wouldn't have had the capability to do anything with it. If it had been sometime recently, say after the Challenger disaster, I doubt it would have got funding...

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#106

Post by Vecr »

mmooss wrote: post #94
augusto-moura wrote: post #46

Earlier quoted context omitted.

I don't know the exact reasons why Vikram didn't get a fission reactor. But I can assume from similar missions: 1. Solar is pretty good as far as Mars and it gets worse as it travel further from the Sun. This is why most probes that travel past Mars need a nuclear reactor (Voyager, Pioneer, Cassini, etc). Going closer to the sun they get even better 2. Sending radioactive materials on rockets presents a risk and it i…

> fission reactor Am I wrong that the plutonium in the Voyagers is not in a fission reactor but in an RTG (Radioisotope Thermoelectric Generator), which converts the heat from the plutonium into electricity. ? I suppose the heat is result of fission, but I don't think an RTG is what is meant by a fission reactor. ??

Voyager uses a RTG. The USSR used some full-on nuclear reactors in space, but as far as I know no one else publicly did.

Edit: Yep, not sure how I forgot about that.

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#107

Post by Sharlin »

grapesodaaaaa wrote: post #25
pupppet wrote: post #13

I didn’t realize the Voyagers relied on a once in a 175 year planetary alignment. What a lucky break technology had advanced to the point we could make use of it.

I’m trying to figure out why the alignment was so important. Wouldn’t it be possible to get a gravity assist in any alignment - albeit just taking a little longer to ping-pong across the system?

No, there's no pingponging. There's only so much momentum you can exchange with a planet, because there's only so close a flyby that you can make before it stops being a flyby and becomes a fly-into.

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#108

Post by harrisi »

fwipsy wrote: post #97
timthorn wrote: post #22

Earlier quoted context omitted.

Ah, yes - The Jupiter Effect: https://www.goodreads.com/book/show/3400930-the-jupiter-effe...

Forward by Isaac Asimov? I'm surprised he would have his name associated with this.

Not just any foreword, a pretty big endorsement. You can borrow the book from the internet archive to read the full foreword, but here's the last bit:

    And in the end, it turns out that something will happen in 1982 that just may—
    No, no, read it for yourself. Read it carefully and you'll find it far more fascinating than the tale of any millionaire found stabbed in any library, locked or otherwise. And far more important, too especially if you live in California.

    ISAAC ASIMOV
    17 April 1974

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#109

Post by rightbyte »

gruturo wrote: post #18
voytec wrote: post #15

Earlier quoted context omitted.

> the "battery" in the old ones is nuclear and it's going to be difficult to beat that Newer atomic batteries can theoretically last centuries instead of decades. V'ger 1 atomic battery is based on Plutonium-238 which has a halflife of ~88 years. It's down to ~210W output from initial 470W at launch time. Americium-241 has a half-life of over 400 years.

The longer the half life, the lower the power output, no free lunches. But by putting the same suitable radioactive lump in a stirling engine you can extract 4 times as much electricity: https://en.wikipedia.org/wiki/Stirling_radioisotope_generato... So yes maybe with Americium-241 we could have something which lasts 4 times a much _and_ gives us the same amount of power thanks to a SRG.

Using a sterling motor would give you mechanical wear.

Re: Voyager 1 breaks its silence with NASA via radio transmitter not used since 1981

#110

Post by nick__m »

floatrock wrote: post #45
selectodude wrote: post #39

Earlier quoted context omitted.

Using plutonium works great but there are two issues. 1) they don’t output that much power. Few hundred watts at most, and they decay at a fixed rate. 2) you need to get your hands on a decent amount of plutonium. Great for dirty bombs, hard to source.

Isn't it something like space-reactor plutonium is a waste product from nuclear weapons production, and since we don't really make nuclear weapons at scale anymore, we aren't really making (refining?) plutonium anymore. And NASA has some amount on reserve, but they're rationing it out carefully. So the Clipper probe had to go with a massive solar array (100ft, the length of a basketball court) because they would rath…

it don't make sense to stock hot plutonium to use it later, it loose power and decays overtime wherever you use it or not!
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