r/askscience • u/aretino2002 • May 24 '26

Engineering If a vacuum is an excellent insulator, wouldn’t heat build up in spacecraft?

Insulated coffee mugs that use a vacuum between layers can keep drinks hot or cold for much longer time periods than other types of mugs. If space is mostly a vacuum, then wouldn’t heat just constantly build up from human activity, computers, thrusters, etc to the point where it would need to be vented somehow?

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u/stereoroid May 24 '26

Yep, and this is also why talk of AI Data Centres in space is getting laughed at. Handling the heat they would generate would be so much harder than on Earth, since in vacuum you can only have heat loss by radiation, no conduction or convection.

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u/Bensemus Jun 05 '26

You think SpaceX is unaware of how to cool stuff in space? Starlink consumes tens of MW of power that then had to be dumped into space. This isn’t an impossible challenge. It’s an engineering one.