I don't know what I've been told..
Out space is very cold. 🥶 
🇳🇱
I don't know what I've been told..
@stux its just a few kelvins near earth. somethng like -270 C
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@freemo That's bloody damn cold if you ask me 
brrr
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@stux I do suggest a sweater and scarf yes :)
Interesting fact, despite being super cold it is rather tricky to cool things in space... cause physics :)
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@freemo Not gonna cut it
Ah yes true! The heat cannot go anywhere! You know.. now air and shizzle or other transport vroom vroom
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@stux well you can still get the heat off of things. But you are limited to one of the three heat transfer methods, radiation. Ther eis no convection or conduction.
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You can also evaporate something (but only as long as you have something to evaporate). Surprisingly many spacecraft used evaporative cooling at least sometimes (Gemini had an evaporator that seemed to have been used at low flow continuously, Apollo LM was cooled purely by evaporation, Apollo CSM had an evaporator to allow higher heat rejection rates than by radiators alone and as the sole way to dispose of heat after the SM was gone, Shuttle had an evaporator to cover high heat load intervals and, I assume, to help in the case the payload doors won't open).
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Actually I forgot one "spacecraft": Apollo portable life support backpack used a sublimator. I _think_ all the spacecraft I mentioned previously used evaporators, but am less sure than previously (esp. about the LM, which had to support very low power levels). Funnily enough, in some cases the evaporator (or the steam piping from it) actually had an electrical heater to prevent freezing.
Apollo CSM, late Gemini, and Shuttle had an overabundance of water (because they were powered by hydrogen-oxygen fuel cells), but that water had to be condensed from steam first, so the evaporator was essentially part of "negative heat storage" system. Apollo LM was constrained to a very short period of operation by many other constraints (e.g. the descent engine would become inoperable IIRC 72h after it was first used, and something like a week after launch).
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Wikipedia doesn't say anything about water droplet radiators behind able to handle higher temperatures. I also don't understand how would that be possible: the liquid, before being sprayed has to be pumped through pipes, so we need to have a material that can withstand that temperature (and I naively expect that adding the "has reasonably high thermal conductivity" requirement doesn't narrow things that much; does it?).
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like liquid metal
https://en.wikipedia.org/wiki/Liquid_droplet_radiator
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Hm~ I'll need to look up examples of materials used for high-temperature pipes. I had a baseless impression that they're always metal (well, not completely baseless -- they need to be flexible or to have very small thermal expansion coefficient).
What kind of rules you'd want to lawyer? My impression is that the temperature of the coolant is limited by the temperature the device being cooled can handle. Ah, we could try pumping heat from the device into the coolant, thus increasing the cooling power (because coolant's hotter), while paying some penalty in having generated some additional heat (because efficiency of heat pumps is thermodynamically limited)? Thanks, I'll need to think about it.
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@robryk
Yes very true but evaporative coolin can be tricky since it can freeze and slow the heat transfer. Plus as you say, it requires a "fuel" that is expended to do it.
@stux