Thermal modelling of a small satellite data processing unit aided by sensitivity analysis and uncertainty quantification

Sensitivity analysis (SA) and uncertainty quantification (UQ) were used to verify the thermal design of the Intuition-1 nanosatellite data processing unit (DPU). For that purpose, a numerical model of the satellite was developed and validated against experimental data, which were obtained in thermal-vacuum chamber experiments. First, a simplified approach was applied to identify and eliminate less important parameters from further analysis. In the second step, a second-order probability approach was utilized to take into account the epistemic and aleatory uncertainties in the UQ study. The results identified crucial design parameters and the separate influence of aleatory and epistemic input uncertainty on the output variables. The results showed that the design of the nanosatellite DPU does not require modification and that minimizing the uncertainty of the input could considerably reduce the output uncertainty. The presented methodology can be applied to other systems to identify the importance of individual design parameters and predict the uncertainty of key responses under mixed aleatory and epistemic uncertainty. This process is crucial for the robustness of thermal design and provides valuable information supporting project decisions.