Starship Radiators

Re:Starship Radiators by Pinckney on Tuesday February 04, 2014 @11:19AM (#7178344)

Any engine worth using will produce large amounts of waste heat, which the ship will need to reject somehow. The most plausible option seems like large radiators; efficiency is as the fourth power of temperature, so it is very desirable to run radiators as hot as possible. 600-2000K are fairly plausible values.

Thermal insulation isn't necessary or helpful, except as it separates crew spaces from hot spaces and gives the radiators time to reject heat.

Also, the exhaust plume will be very hot and very bright. Even if the ship doesn't radiate, the exhaust will

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[deleted]

Re:Starship Radiators by dalke on Tuesday February 04, 2014 @01:12PM (#7179185)

> In order for a radiator to do its job, it has to be immersed in some sort of working medium ... You can sort of make a "radiative transfer" radiator, but they don't work quite the same.

You should re-read Pinckney's essay on the assumption that it specifically concerns the latter type of radiator. Consider that "efficiency is as the fourth power of temperature" is a reference to the Stefan–Boltzmann law for black-body radiative heat transfer.

Consider too that the linked-to essay, in the part about radiative cooling and with worked-out details about Stefan-Boltzmann, refers to a working temperature of 2200 K, where the T-to-the-fourth really kicks in.

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