Accuracy of Extrapolation of Equilibrium Temperatures of Transient Fields of Temperature with Two Different Mathematical Approaches

A key element of spacecraft thermal balance testing is the reliable determination of the final temperature values of the temperature equilibrium. At the end of a thermal balance test phase, temperature equilibrium is generally considered to be reached when nearly all thermocouples have fulfilled pre-defined temperature equilibrium criteria, e.g. in the form of a maximal allowed rate of temperature change.

Test time can be reduced in the same manner as the equilibrium temperatures can be reliably extrapolated from the measured thermocouples temperatures, thus requiring only a less stringent equilibrium criterion to be fulfilled by the sensed temperatures.

This paper concentrates on a mathematical theory for practical use in the extrapolation of equilibrium temperatures for spacecraft and units with essentially radiative couplings to their thermal environment.