Thermo-mechanical analysis and validation of high-stability support design for star trackers

This study addresses the high-precision pointing requirements of satellite star trackers by co-designing and validating the thermal-mechanical support structures. Based on the thermal characteristics of the star sensor, a thermal resistance network method was employed to establish a heat dissipation distribution model for the mounting flange, clarifying external heat transfer properties at installation nodes. To resolve inherent deformation transfer in traditional heat pipe layouts, a composite support structure integrating copper-mesh flexible thermal straps and support-point slit designs was developed. By combining thermoelastic displacement decoupling mechanisms and distributed compensation for thermally induced strain, the deformation of the mounting plate under non-uniform temperature variations was effectively suppressed. Utilizing bidirectional thermal-structural field coupling technology, a joint predictive model for thermal warpage and modal characteristics was established, achieving critical performance metrics under extreme conditions: normal-axis pointing stability (0.93 "/K) and structural fundamental frequency (>110 Hz). Ground test results showed a maximum relative error of less than 3.1% between measured data and numerical predictions, confirming the model’s engineering validity. In-orbit validation demonstrated superior thermal stability (control point fluctuations < ± 0.2 K) and pointing accuracy (surpassing 0.86 "/K), meeting the high-precision positioning demands of star trackers.