7.1 Definition

The thermal control system manages the temperatures of the components within the S/C. Its responsibility is to reject the heat of the components dissipating power to keep them within their allowable flight temperature (AFT) range. This is accomplished through heat transfer. Heat transfer includes convection, conduction, and radiation of which conduction dominates heat transfer internal to the spacecraft and radiation dominates heat transfer external from the spacecraft to the space environment. The thermal control system utilizes these fundamentals of thermodynamics to keep the spacecraft within operational temperature ranges for the spacecraft components.

Spacecraft have to survive in extremely hot and cold environments and have to withstand extreme temperature changes in short amounts of time. The thermal control system distributes temperature sensors throughout the spacecraft, emphasizing temperature-sensitive components. A thermal control subsystem can have two flavors of technology: passive and active. A passive thermal control system does not need power or control logic to regulate heat transfer. An active thermal control system reacts to temperature changes detected from the sensors by powering heating or cooling technologies to regulate the components. The thermal control system can be one distinct component, like a cryocooler, but can also be distributed or embedded in other components as thermal design features, like OreSat’s use of copper conduction strips at the edge of electronics boards.