7 ms·

Yeah, you got a lot of it and the ripple effect of things that go out from it. In addition to the extra mass of the camera and solar arrays, there is extra mass

Yeah, you got a lot of it and the ripple effect of things that go out from it. In addition to the extra mass of the camera and solar arrays, there is extra mass for the harnessing to connect the camera to the computer and engineering design for that as well. Integration of anything else on the spacecraft will have to go through Failure Modes Effects and Criticality Analysis (FMECA). Basically, this gets in to pretty detailed circuit design analysis and makes sure that any failure on the camera itself (like a short circuit or babbling idiot data bus) won't impact the rest of the spacecraft. Potential cost of increased storage onboard the spacecraft if it is significant data volume. Cost of downlinking the data to the ground, time on the DSN is expensive. I think the cost data sheets for DSN usage are online and it depends on data rate, what dish you are using, etc. but costs for usage are on the order of thousands per hour and data rates from Jupiter are pretty slow. The cost of the camera itself is likely on the order of a couple hundred thousand. I've seen similar costs for small radiation hardened cameras and star trackers. The difference in parts cost for some things can be absolutely insane. Passive electrical components certainly cost more, but for active circuits it can be insane. A radiation hardened equivalent of a $20 FPGA can be something like $20,000. All told, cost of integration and use over the mission is likely at least a few million. But on a $1.1 billion mission it still doesn't seem like a lot.

grahamj 2y ago
I’m reminded of the thread from the other day about “just” doing something. We’ll just add a camera, no biggie! Still, I’m very glad they did it. Arguably the second most beautiful planet :)
- deleted 2y ago
  [deleted]
vlovich123 2y ago
> A radiation hardened equivalent of a $20 FPGA can be something like $20,000 Has anyone actually tried putting up non-rad hardened equipment to measure how they perform? The Mars helicopter wasn't RAD hardened and used off the shelf parts & succeeded and the Mars atmosphere is not thick enough to meaningfully block the amount of cosmic rays hitting the surface. I think NASA doesn't do a good job sometimes tolerating risk and then everything is treated as needing safety-levels of risk mitigation without considering that a 1/100th cost reduction will not generate as much in parts failures.
- dr_orpheus 2y ago
  Yep, they do! I had some of this discussion on a thread talking about the Mars helicopter here that Goddard does a lot of radiation testing on commercial chips. https://news.ycombinator.com/item?id=39175423#39182421 https://news.ycombinator.com/item?id=39175423#39182421 Lots of the new space, and smaller satellite companies use a lot of commercial parts. A lot of the flight data has shown even better results than the radiation testing (possibly due to added stress of testing at higher rates vs low rates over longer mission duration). Generally speaking most of this is in LEO with a pretty low radiation environment. Whereas the area around Jupiter is one of the worst radiation environments in the solar system due to the radiation belts (like the Van Allen belts on steroids). This page on the Juno Radiation Vault says the spacecraft is exposed to an anticipated 20 Mrads of radiation. Whereas spacecraft in LEO are exposed to 0.1-10 krads per year depending on the orbit. Also a fun fact, this is with Juno trying to limit exposure to the radiation belts as much as possible. [1] [0] https://en.wikipedia.org/wiki/Juno_Radiation_Vault https://en.wikipedia.org/wiki/Juno_Radiation_Vault [1] https://en.wikipedia.org/wiki/Juno_(spacecraft)#/media/File:Juno_trajectory_through_radiation_belts.png https://en.wikipedia.org/wiki/Juno_(spacecraft)#/media/File:...
  - vlovich123 2y ago
    Ok. That's a good point about the radiation belts. I hadn't considered that Jupiter's massive magnetosphere captures & concentrates a huge amount of solar energy & Juno is very close to it. Thanks for the additional info!
- fecal_henge 2y ago
  Lots of work on this in the High Energy Physics community. Big experiments can design their own rad hard silicon, but everyone else has to test. Lots of space rated electronics is also qualified at far lower levels than we need. Upside ia that people are happy to share what they find: https://arxiv.org/pdf/1912.01742.pdf https://arxiv.org/pdf/1912.01742.pdf https://twiki.cern.ch/twiki/bin/view/Main/RAD-HARD-COMP https://twiki.cern.ch/twiki/bin/view/Main/RAD-HARD-COMP
- dr_orpheus 2y ago
wkrsz 2y ago
TIL "babbling idiot" is a technical term https://www.wikidata.org/wiki/Q797603 https://www.wikidata.org/wiki/Q797603 > failure condition on a computer bus or network in which a malfunctioning node sends data at inappropriate times thus interfering with the communication of the working nodes

grahamj 2y ago

I’m reminded of the thread from the other day about “just” doing something. We’ll just add a camera, no biggie! Still, I’m very glad they did it. Arguably the second most beautiful planet :)

deleted 2y ago
[deleted]

vlovich123 2y ago

> A radiation hardened equivalent of a $20 FPGA can be something like $20,000 Has anyone actually tried putting up non-rad hardened equipment to measure how they perform? The Mars helicopter wasn't RAD hardened and used off the shelf parts & succeeded and the Mars atmosphere is not thick enough to meaningfully block the amount of cosmic rays hitting the surface. I think NASA doesn't do a good job sometimes tolerating risk and then everything is treated as needing safety-levels of risk mitigation without considering that a 1/100th cost reduction will not generate as much in parts failures.

dr_orpheus 2y ago
Yep, they do! I had some of this discussion on a thread talking about the Mars helicopter here that Goddard does a lot of radiation testing on commercial chips. https://news.ycombinator.com/item?id=39175423#39182421 https://news.ycombinator.com/item?id=39175423#39182421 Lots of the new space, and smaller satellite companies use a lot of commercial parts. A lot of the flight data has shown even better results than the radiation testing (possibly due to added stress of testing at higher rates vs low rates over longer mission duration). Generally speaking most of this is in LEO with a pretty low radiation environment. Whereas the area around Jupiter is one of the worst radiation environments in the solar system due to the radiation belts (like the Van Allen belts on steroids). This page on the Juno Radiation Vault says the spacecraft is exposed to an anticipated 20 Mrads of radiation. Whereas spacecraft in LEO are exposed to 0.1-10 krads per year depending on the orbit. Also a fun fact, this is with Juno trying to limit exposure to the radiation belts as much as possible. [1] [0] https://en.wikipedia.org/wiki/Juno_Radiation_Vault https://en.wikipedia.org/wiki/Juno_Radiation_Vault [1] https://en.wikipedia.org/wiki/Juno_(spacecraft)#/media/File:Juno_trajectory_through_radiation_belts.png https://en.wikipedia.org/wiki/Juno_(spacecraft)#/media/File:...
- vlovich123 2y ago
  Ok. That's a good point about the radiation belts. I hadn't considered that Jupiter's massive magnetosphere captures & concentrates a huge amount of solar energy & Juno is very close to it. Thanks for the additional info!
fecal_henge 2y ago
Lots of work on this in the High Energy Physics community. Big experiments can design their own rad hard silicon, but everyone else has to test. Lots of space rated electronics is also qualified at far lower levels than we need. Upside ia that people are happy to share what they find: https://arxiv.org/pdf/1912.01742.pdf https://arxiv.org/pdf/1912.01742.pdf https://twiki.cern.ch/twiki/bin/view/Main/RAD-HARD-COMP https://twiki.cern.ch/twiki/bin/view/Main/RAD-HARD-COMP
dr_orpheus 2y ago

wkrsz 2y ago

TIL "babbling idiot" is a technical term https://www.wikidata.org/wiki/Q797603 https://www.wikidata.org/wiki/Q797603 > failure condition on a computer bus or network in which a malfunctioning node sends data at inappropriate times thus interfering with the communication of the working nodes