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Comment by elihu | Hacker News Reader

Aluminum vs copper is a good example. Another is that we already do use superconducting transmission lines in a few places. We could do more of that, but presumably it's expensive to install and/or maintain otherwise we'd be using it everywhere. I'm not sure what the longest or highest capacity superconducting links currently in existence are.

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That have to be kept cool with liquid nitrogen, so it would have to be pretty darn short.

Actually no: they have to be insulated well. People forget that it doesn't actually take energy to stay cool, just to remove the heat. The issue is what's your heat gain from insulation inefficiency per length - and it does get better then thicker your cable gets, because volume increases more rapidly then surface area.

If you're dealing with usecases that need to be cooled anyway, you may well be better off with the tradeoff of needing liquid nitrogen cooling and better insulation in exchange for entirely eliminating resistive heat.

I wonder if we can use these superconducters on spacecraft and probes. Maybe we can place superconducting links on the outer hull of a spacecraft heading to Mars, or a probe heading into outer space.

Cooling them would still be a problem. The sunny side might not be the best place for them.

They might find a niche in some instruments in probes, but for wiring it does not make sense. The rest of the probe electronics don't like being that cold.

But why? What is the problem you are trying to solve by placing superconducting links on the outer hull of spacecraft?

High-temperature ones can be cooler with liquid nitrogen. Standard ones, the ones most commonly used, require liquid helium.

Well, I think it comes down to whether the energy cost of active cooling is better or worse than resistive losses. Which one is better doesn't depend on cable length.

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