The test methods involve thermal cycling and thermal balance in a vacuum or at ambient pressure and vibration testing.
Key thermal and mechanical properties of space components need to be measured, such as thermal conductivity, thermal efficiency of multilayer insulation (MLI) and coefficients of thermal expansion. These measurements are essential to analyse and predict the overall thermo-mechanical performance of a space system in flight conditions.
Laboratory expertise also provides significant support for the investigation of in-orbit anomalies. The laboratory can subject space hardware to hot and cold environmental conditions in vacuum, including solar simulation. Climatic chambers at ambient pressure (with air or other gases) are also used to simulate a pressurised environment or a planetary environment such as Mars.
Two main types of thermal tests are carried out.
The laboratory measures material properties such as thermal conductivity and coefficient of thermal expansion and has developed a dedicated method and facility to measure the thermal efficiency of MLI blankets.
The laboratory also performs vibration testing. Typical test articles undergoing both thermal and mechanical tests include solar cell sample panels, equipment, instruments and CubeSats.
For thermal testing, the most important facilities are two medium-sized vacuum chambers (usable volume: 850 mm diameter by 1.5 m long and 1.9 m long), either of which can be used with a 350 mm-diameter beam solar simulator. There are several smaller thermal vacuum chambers equipped with a shroud and/or cold plate system. Depending on the selected facilities and the type of test, the attainable temperatures range from 10K to 390K. An infrared camera can be used for non-intrusive temperature measurements. Dedicated facilities are available for the measurement of thermal efficiency of MLI, coefficient of thermal and moisture expansion.
A special thermal vacuum cycling facility was developed to allow quick cycling between a hot compartment (up to 600ºC), and a cold compartment (down to –240ºC). This facility automatically moves the test specimen between the two compartments to achieve fast thermal cycling. The usable volume is of 650 X 500 x 350 mm.
An electrodynamic vibration system with 22 kN force is used to generate sine and random excitation. Active accelerometers and force sensors are connected to a 40-channel data acquisition system. In addition, a laser vibrometer can be connected to the system for non-intrusive measurements. Test adapters can be designed for dedicated tests.
The laboratory also has access to powerful thermal computing facilities and associated software tools for designing test set-ups, modelling, conducting post-test thermal correlation and performing the general analysis of test results.