Update on the NASA Voyagers - Page 1
Forum section: electronics / general

author: Benta
author_rank: Super Contributor
timestamp: October 24, 2023, 07:46:45 pm
content: I'm just fascinated about this mission:https://arstechnica.com/space/2023/10/nasa-wants-the-voyagers-to-age-gracefully-so-its-time-for-a-software-patch/

author: mendip_discovery
author_rank: Super Contributor
timestamp: October 24, 2023, 08:27:31 pm
content: I wish they would send more like this out there. With what we know we might be able to improve their abilities and maybe get them further out. Or at least get a snapshot of the same data but 50 year apart.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: October 24, 2023, 08:33:03 pm
content: Just wondering what sort ofcapactors are being used here.Built during pre-capacitor plague earaProbably the circuits use as few capacitors as possible.

author: Gyro
author_rank: Super Contributor
timestamp: October 24, 2023, 08:46:10 pm
content: Any capacitors of significant size are probably Wet Tantalum.

author: Gyro
author_rank: Super Contributor
timestamp: October 24, 2023, 08:53:43 pm
content: Quote from: mendip_discovery on October 24, 2023, 08:27:31 pmI seem to remember some controversy about thesafetyrisks of launching Radioisotope powered SVs. I can't find much on the NASA website in the way of recent launches - although most other stuff can be done with solar panels.

author: TimFox
author_rank: Super Contributor
timestamp: October 24, 2023, 09:08:37 pm
content: There is indeed controversy surrounding the plutonium-pile powered spacecraft, which use a thermopile (battery of thermocouples) stuck into the reactor to generate electrical power.The main contention was possible problems if the spacecraft failed during launch, before leaving the Earth.Seehttps://rps.nasa.gov/technology/for NASA's description.

author: Benta
author_rank: Super Contributor
timestamp: October 24, 2023, 09:36:44 pm
content: "Reactor" is a bit over the top to my mind. It evokes images of "China Syndrome" etc.It's simply a lump of238Pu with thermogenerators stuck to it.Apart from the fact of Pu being somewhat poisonous, I don't see a radiation issue.

author: Benta
author_rank: Super Contributor
timestamp: October 24, 2023, 09:45:25 pm
content: Quote from: mendip_discovery on October 24, 2023, 08:27:31 pmSo do I. But the Voyager missions were based on a special planet constellation that enabled "slingshot" acceleration by passing close by two/three of the big planets.Back then, it was a breathtaking race to get them launched to take advantage of that. So they were built "quick-n-dirty" and still survive.Something to think about.

author: TimFox
author_rank: Super Contributor
timestamp: October 24, 2023, 10:02:43 pm
content: Quote from: Benta on October 24, 2023, 09:36:44 pmTo get heat from plutonium, you need to assemble enough to create a chain reaction.This is usually called a "pile" or a "reactor".Plutonium, in fact, is poisonous, like other heavy metals, but its radiation is not a big problem if you don't ingest it.

author: rdl
author_rank: Super Contributor
timestamp: October 24, 2023, 11:39:00 pm
content: RTGs use the heat from normal radioactive decay of plutonium. No chain reaction is involved.

author: TimFox
author_rank: Super Contributor
timestamp: October 24, 2023, 11:49:03 pm
content: Yes, that's true of the RTG as discussed in the NASA article.Actual fission reactors have been used in spacecraft by the Soviet Union, and once by the US for higher power in spacecraft.See a discussion inhttps://world-nuclear.org/information-library/non-power-nuclear-applications/transport/nuclear-reactors-for-space.aspxPossible electrical generators discussed include thermopiles and Sterling heat engines.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: October 24, 2023, 11:59:16 pm
content: For me (as a certified tapehead) the most interesting fact is that Voyager 2 has a (still operational AFAIK)tape recorder on board.CheersAlex

author: Psi
author_rank: Super Contributor
timestamp: October 25, 2023, 12:30:15 am
content: Quote from: Benta on October 24, 2023, 09:36:44 pmThe issue, I think, was a mission failure where the craft re-enters the atmosphere and burns up. You don't want to spread a mist of Pu238 over a wide area.I seem to recall the radioactive material is somewhat shielded in a way to survive reentry intact. But there is always a risk, it could get hit with other space debris and shattered into small pieces before re-entering.But if we want to explore the outer solar system it's really the best option.

author: Andy Chee
author_rank: Super Contributor
timestamp: October 25, 2023, 05:05:53 am
content: Fission reactors were probably deemed too unreliable for deep space probes (too many moving parts for control rods) as retrieving the satellite for repair is not an option, hence the preference for RTGs (zero moving parts).Uranus and/or Neptune are priority targets for NASA for an orbiter probe, similar to Cassini & Saturn, so watch this space. Any launch trajectory will inevitably require gravity slingshots, probably from Venus and/or Earth.

author: FrankBuss
author_rank: Unknown
timestamp: January 01, 2024, 11:27:17 am
content: I wonder if there are details about the computer on the Voyager and the software, or even an emulator. I just found some general descriptions, like that they are using 3 computers, and Fortran and assembler. I guess NASA has an emulator for it? Would be fun to play with.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 01, 2024, 05:07:01 pm
content: Weren’t these the probes fitted with COSMAC processors?

author: FrankBuss
author_rank: Unknown
timestamp: January 01, 2024, 05:19:25 pm
content: No, looks like this is a misconception, according to this site:https://www.retrotechnology.com/memship/1802_spacecraft.htmlQuote