system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If it's so difficult to cool things down in space, how do satellites and the ISS not overheat from sunlight?
gpt
Most surfaces are painted white or coated in reflective material to reduce absorption of sunlight.
There may also be areas painted black that face away from the sun that radiate heat.

White absorbs light/IR the least, but also radiates heat the least.
Black absorbs the most, but radiates the most too. By using both in the right positions, the temperature can be controlled.

Thermal management is basically all about moving heat to a part of the spacecraft designed to radiate heat to keep the craft cool.