Blackbody Radiation and Thermal Control of Satelites.

[Patrick]

With regards to satellites how is the Blackbody principle use to assist in thermal control ? I have know idea how to make sense of anything Ive read online. It seems like it emits radiation more at high temperature and less an cooling temperatures. If that's true is the surface area wisely chosen to not overheat or over cool a given system ?

what about silver with an emmisivity of 0.02, can that be used to prevent absorption in the first place ? ive looked here too :

https://technology.nasa.gov/patent/GSC-TOPS-40

[klugesmith]

It's about heat flows to approach radiative equilibrium with the environment,
which is very hot for a black surface in sunlight, and very cold for a black surface facing away from the sun.
More nuanced for white or mirror-like surfaces.  Traditionally tested in large "thermal vacuum chambers", that have LN2-cooled cold walls, sunlight-simulating illuminators, and doors bigger than the equipment under test.  Maybe superseded by numerical simulation in recent decades.

Decades ago, some satellite electronics bays were set up with Venetian blinds, opened and closed by bimetallic coil actuators.   Sounds particularly useful for LEO satellites that experience day and night in every orbital cycle.