"A satellite is, if nothing else, a fantastic thermos."

A satellite is quite unlike a thermos in the sense that it is carefully tuned to keep its temperature within a relatively narrow band around room temperature.[1] during all operational phases.

This is because, despite intended space usage, devices and parts are usually tested and qualified for temperature limits around room temperature.

[1] "Room temperature" is actually a technical term meaning 20°C (exceptions in some fields and industries confirm the rule).