Optomechanothermal analysis and testing of the large-aperture space Tx/Rx common-aperture system

Large-aperture space Tx/Rx common-aperture systems (LASTRCAS) are increasingly being utilized in deep-space exploration and laser energy transmission. However, research on the optomechanical thermal analysis and testing of these systems in space environments remains limited. This study systematically investigates the optomechanical thermal characteristics and testing methodologies of such LASTRCAS from three perspectives: mechanical stability design, thermal stability design, and stray light analysis and testing. A hybrid structure design incorporating silicon carbide/aluminum materials and carbon fiber composites effectively reduces the impact of in-orbit gravity release on the combined wavefront aberrations (CWA) of the primary and secondary mirrors. Through the application of a multi-parameter synchronous optimization model, the CWA of the primary and secondary mirrors is minimized to 0.011 λ (λ=632.8nm) under 1 g gravity conditions. In combination with advanced thermal control techniques, the maximum temperature rise of the primary mirror is maintained within 2°C, while that of the secondary mirror is controlled within 0.5°C. Under actual temperature conditions, after defocusing, the CWA of the primary and secondary mirrors achieves 0.007λ. Additionally, surface scattering tests and numerical simulations have been performed for all critical surfaces within the system. An innovative single-photon counting method has been introduced to enhance the sensitivity of stray light testing. System-level stray light testing for meter-scale aperture systems has been successfully conducted under ISO 7 cleanroom conditions, achieving a PST (30°) value of 6.4×10^-6. The results of this study provide essential references for the design and testing of large-aperture transmit-receive common-aperture systems in space applications.