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It sound like standard electrical wire as you would use in earth bound transportation would have a significantly shorter life in the vacuum of space. (See related Do plasticizers evaporate in space?) Mostly due to the insulation becoming fragile with age.

Google is telling me that standard household wiring has a life expectancy of 40 to 80 years. With technological improvements adding to the expected, life each generation. I did not find a life expectancy for automotive wire, it seems like the cars useful life is generally less then the electrical wire.

If I want to plan for long term (decades or centuries) in space, what type of electrical wiring provides the longest life in space?

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  • $\begingroup$ The quality of the isolation may be very different. There are better materials for the use in space than PVC, teflon, kapton, woven glas fibers. $\endgroup$
    – Uwe
    Commented Jan 13, 2018 at 20:05
  • $\begingroup$ Gold, platinum, tantalum, niobium, etc. are very good. For some reason, the universe has conspired against us by making the best materials the rarest and most expensive ;) Seriously, gold is used a lot because it does not oxidize easily and it is highly conductive. You generally want to avoid insulators in space as there is no ground so your spacecraft can charge up a lot. If you charge up enough, arcing will occur and that will ablate sizable fractions of the spacecraft bus or instrumentation, which is not good. $\endgroup$
    – honeste_vivere
    Commented Jan 19, 2018 at 15:50
  • $\begingroup$ @honeste_vivere can you expand this into an answer? Comments are not a good location to try and provide an answer. $\endgroup$
    – James Jenkins
    Commented Jan 19, 2018 at 16:10
  • $\begingroup$ @JamesJenkins - I was not trying to answer, only trying to add a few details to the already good answer by Rory. I did not think it was sufficient to merit it as an answer. $\endgroup$
    – honeste_vivere
    Commented Jan 19, 2018 at 16:17

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This is a rather major issue. As you pointed out, plastics etc don't cope well in space. That said, there are numerous insulator materials which will do just fine. But atomic oxygen and solar radiation degrades many substances exposed to space.

But this is really only an issue for external wires that require insulation... So let's look at the challenges as detailed by NASA:

  • Arc tracking
  • Offgassing
  • Flammability
  • Thermal decomposition
  • Microbial growth

Of these, arc tracking is the most relevant to cables in vacuum, and NASA have looked at the effect of ageing on this issue.

  • communication wiring: in general you'd want this inside, partly for ease of maintenance, and partly for the slight additional shielding the capsule walls give against stray particles and interference. Electrical comms is expected to be replaced with optical comms in future anyway.
  • power wiring: most of this will be internal, except for connections to solar panels etc. The insulation requirements here are relatively straightforward, and can be delivered with a range of solutions from plastics and ceramics to none at all. (Although ceramics are brittle, so have their own challenges during launch...)

The specification for cables such as the FCC connector to solar panels etc is for a 15 year exposure to atomic oxygen and 15 years elapsed exposure to the sun (10 effective years)

See https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940024194.pdf

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  • $\begingroup$ I'd say offgassing is also a potential problem: as the plastic offgasses, it will become brittle over time. Ultimately, insulation may break off due to vibration or wires moving (e.g. wires connected to moving parts). $\endgroup$
    – Hobbes
    Commented Jan 13, 2018 at 13:43

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