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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

#61

Post by westurner »

vikingerik wrote: post #55
grapesodaaaaa wrote: post #25

Earlier quoted context omitted.

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?

The scenario where a gravity assist doesn't work is if turning sharply enough would require your minimum planetcentric approach distance to be less than the radius of the planet - you'd crash into it instead. This is why Voyager 2 couldn't also do Pluto - it would have needed to change course by roughly 90º at Neptune, which would have required going closer to the center of Neptune than Neptune's own radius. The most…

Could Voyager have reduced velocity, glanced off Neptune, waited for the return path on a narrow elliptical orbit, and then boosted to effectively make the 90° turn to Pluto at that time? Was that impossible given its Neptune approach trajectory, or would glancing off and waiting have been more fuel?

And, why didn't this vortical model that includes the forward velocity of the sun make a difference for Voyager's orbital trajectory and current position relative to earth? https://news.ycombinator.com/item?id=42159195 :

> "The helical model - our solar system is a vortex" https://youtube.com/watch?v=0jHsq36_NTU

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

#62

Post by vikingerik »

NikolaNovak wrote: post #30
iamgopal wrote: post #3

Can we send a voyager 3 with much advance battery and sensor, and at much faster speed so that it may reach farther than voyager 1 and 2, in let’s say just couple of years ?

My understanding is that 1. Our rocket / propulsion technology today may be cheaper (thx largely to SpaceX), but it doesn't really necessarily provide MUCH more delta V. Meanwhile 2. Voyager launches relied on a once-in-a-blue-moon (not quite once in two centuries) alignment of various planetary bodies to give a spectacular orbital slingshot boosts. So my limited understanding is that we can't really overtake voyager…

The alignment isn't what matters for overtaking Voyager. Jupiter alone is enough, and New Horizons nearly did. Jupiter accounts for the vast majority of any gravity-assist plan. Saturn has 30% the mass and 2/3 of the orbital velocity, so it could only add 20% more over what you get from Jupiter alone, and the ice giants are smaller and slower yet.

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

#63

Post by Salgat »

gdubs wrote: post #31

I'm reading Pale Blue Dot to my kids at night currently so this is really awesome. (The Voyager missions are described in excellent detail in ways that I never appreciated fully before.) It blows my mind that these are machines from the 8-track era. And they have fallbacks and redundancies that were completely ahead of their time.

NASA loves to downplay expectations in case something goes wrong, but people really underappreciate just how overengineered these things are, which makes sense when a bad mission can be political suicide for their future funding.

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

#64

Post by Salgat »

freeone3000 wrote: post #49
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…

Sure! First, the nuclear power source is a giant hunk of plutonium. It is expensive to get, dangerous to use, and due to concerns about further refinement, is restricted internationally. Second, it is toxic inherently — the source is continuously radioactive at a hazardous level to humans, plutonium itself has acute and long-term toxic effects aside from the radioactivity, and if a launch fails, the rtg will disinteg…

I wonder if you could do a hybrid approach, where the nuclear device is very small, but able to charge the battery over a longer duration to the point where the solar panels can be repositioned and utilized again.

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

#65

Post by gdubs »

leobg wrote: post #59
gdubs wrote: post #31

I'm reading Pale Blue Dot to my kids at night currently so this is really awesome. (The Voyager missions are described in excellent detail in ways that I never appreciated fully before.) It blows my mind that these are machines from the 8-track era. And they have fallbacks and redundancies that were completely ahead of their time.

Cool! I do the same thing with books like Asimov’s Earth and Space (science) or Lois Lowry’s Number the Stars (fictional history). What other books can you recommend?

Good question but I have a fever at the moment so unfortunately my brain is not fully functioning :/

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

#66

Post by downrightmike »

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?

Speed run hacking

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

#67

Post by kibwen »

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 successfully did by "coincidentally" being on course to visit Neptune and Uranus after completing its primary mission to Jupiter and Saturn (to this day, Voyager 2 remains the only visitor to Uranus and Neptune)).

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

#69

Post by vlovich123 »

iamgopal wrote: post #3

Can we send a voyager 3 with much advance battery and sensor, and at much faster speed so that it may reach farther than voyager 1 and 2, in let’s say just couple of years ?

> at much faster speed

As others have pointed out, the speeds for Voyager 1 were because of gravity assist of Jupiter and Saturn while Voyager 2 was a gravity assist of Jupiter, Saturn, Uranus and Neptune. Jupiter & Saturn line up relatively often enough so we could try to outdo Voyager 1 speeds a bit with a lighter air craft due to various advancements. But it's unclear we'd learn anything really new from having sensors that reached further out and our technology for propulsion really hasn't meaningfully advanced to outdo gravity assists from Jupiter + Saturn. There's some proposals to use nuclear explosions behind a probe to achieve speeds of ~10k km/s which would be substantially faster but there's numerous obstacles (cost + international treaties banning the use of nuclear in space).

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

#70

Post by stevenwoo »

gdubs wrote: post #31

I'm reading Pale Blue Dot to my kids at night currently so this is really awesome. (The Voyager missions are described in excellent detail in ways that I never appreciated fully before.) It blows my mind that these are machines from the 8-track era. And they have fallbacks and redundancies that were completely ahead of their time.

One feels a terrible disappointment Sagan didn't live to see the future mission projects he talks about in the book get finished and most of them succeeded IIRC. By happenstance the 2024 Solar System BBC series mostly uses animation but has some real photos and videos to document a lot of happened since the book was published.
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