3 ms·

When you're far enough from the sun to avoid thermal cycles, in the vacuum of space, what forces will cause things to deteriorate? If I wanted something to last

by mark-r 9y ago

When you're far enough from the sun to avoid thermal cycles, in the vacuum of space, what forces will cause things to deteriorate? If I wanted something to last forever, deep space would be the perfect place for it.

azernik 9y ago
Radiation, mostly - though close to planets you also get some chemical erosion from high-speed gas molecules. See e.g. this study on plastics erosion in LEO: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170010655.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...
- mark-r 9y ago
  Does the radiation decrease as you get farther from the sun? What's the background radiation in deep space vs. here on Earth?
  - azernik 9y ago
    It definitely gets higher when you leave Low Earth Orbit, because you're leaving the Earth's magnetic field; so the ISS is definitely at the low end of the scale of Voyager's exposure. Not sure how it varies as you leave the solar system - depends on the exact balance between Solar Energetic Particles (particle radiation from the sun) and Cosmic Rays (particle radiation from outside the solar system), and on how much the cosmic radiation increases as Voyager leaves the heliosphere.
ISL 9y ago
-- It is a tough radiation environment. Materials are embrittled and altered over time. -- Many materials age on their own; plasticizers outgas from plastics. You're probably familiar with how once-pliable but now old/aged plastics, even kept sealed in a box, can become crunchy and brittle. -- Chemistry doesn't stop in space. The thrusters are likely to involve chemically-reactive materials. Any little bit of corrosion, stress-corrosion cracking, etcetera could cause anomalous performance. It is wonderful when things still work.
- jacquesm 9y ago
  And then there are vacuum welding and interstellar dust.
  - comstock 9y ago
    Interesting, I didn’t realize cold welding was a problem in space. I assume it can be solved by applying a coating to surfaces that might come in contact with each other.
sliken 9y ago
I believe the thing that will kill voyager is primarily the radioactive decay of it's battery. It's power budget is so low now that it's got most everything off almost all the time. Sadly there is a point where they won't be able to turn on the radio to listen.
incadenza 9y ago
Isn't the more immediate concern that the power supplies are going to run out?
- mark-r 9y ago
  According to Wikipedia the atomic batteries are good until 2025, which isn't so far away anymore. https://en.wikipedia.org/wiki/Voyager_1#Power https://en.wikipedia.org/wiki/Voyager_1#Power

by mark-r 9y ago

azernik 9y ago

Radiation, mostly - though close to planets you also get some chemical erosion from high-speed gas molecules. See e.g. this study on plastics erosion in LEO: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170010655.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201700...

mark-r 9y ago
Does the radiation decrease as you get farther from the sun? What's the background radiation in deep space vs. here on Earth?
- azernik 9y ago
  It definitely gets higher when you leave Low Earth Orbit, because you're leaving the Earth's magnetic field; so the ISS is definitely at the low end of the scale of Voyager's exposure. Not sure how it varies as you leave the solar system - depends on the exact balance between Solar Energetic Particles (particle radiation from the sun) and Cosmic Rays (particle radiation from outside the solar system), and on how much the cosmic radiation increases as Voyager leaves the heliosphere.

ISL 9y ago

-- It is a tough radiation environment. Materials are embrittled and altered over time. -- Many materials age on their own; plasticizers outgas from plastics. You're probably familiar with how once-pliable but now old/aged plastics, even kept sealed in a box, can become crunchy and brittle. -- Chemistry doesn't stop in space. The thrusters are likely to involve chemically-reactive materials. Any little bit of corrosion, stress-corrosion cracking, etcetera could cause anomalous performance. It is wonderful when things still work.

jacquesm 9y ago
And then there are vacuum welding and interstellar dust.
- comstock 9y ago
  Interesting, I didn’t realize cold welding was a problem in space. I assume it can be solved by applying a coating to surfaces that might come in contact with each other.

sliken 9y ago

I believe the thing that will kill voyager is primarily the radioactive decay of it's battery. It's power budget is so low now that it's got most everything off almost all the time. Sadly there is a point where they won't be able to turn on the radio to listen.

incadenza 9y ago

Isn't the more immediate concern that the power supplies are going to run out?

mark-r 9y ago
According to Wikipedia the atomic batteries are good until 2025, which isn't so far away anymore. https://en.wikipedia.org/wiki/Voyager_1#Power https://en.wikipedia.org/wiki/Voyager_1#Power