Infrared thermography at low temperature

In the frame of space mission development, the measurement and control of temperature is an important problem for thermal vacuum and thermal balance tests. Replacing a substantial amount of thermocouples by a non-contact thermographic detector is highly desirable. Our work investigates the feasibility of extending the temperature measurement range of commercial infrared thermographic system to temperatures down to -100 °C for thermal vacuum test (TVAC). It simplifies test integration, and multiplies the number of measurement channels. A test configuration has been built to measure simultaneously infrared thermographic signals of samples cooled down to -100 °C, with different emissivity, using a commercial infrared camera. Management of parasite infrared radiation, estimation measurement uncertainty (absolute and relative) were realised and compared numerical expectation. The demonstration showed that a temperature error of 3 K @ -100°C for high emissivity objects is achievable.