Thermal Radiation Analysis Method and Thermal Control System Design for Spaceborne Micro-Hyperspectral Imager Operating on Inclined-LEO

Thermal control of spaceborne micro-hyperspectral imagers (MHIs) operating in inclined low-Earth orbits (LEOs) presents significant challenges due to the complex and dynamically varying external heat flux, which lacks a stable heat dissipation surface. This study proposes a thermal radiation analysis method capable of rapidly deriving accurate numerical solutions for the thermal radiation characteristics of spacecraft in such orbits. A dedicated thermal control system (TCS) was designed, featuring a radiator oriented towards the +z_s plane, which was identified as having stable and low incident heat flux across extreme solar–orbit angle conditions. The system employs efficient thermal pathways, including thermal pads and a flexible graphite thermal ribbon, to transfer heat waste from the imaging module to the radiator, supplemented by electric heaters and multilayer insulation for temperature stability. Steady-state thermal analysis demonstrated excellent temperature uniformity, with gradients below 0.017 °C on critical optics. Subsequent thermo-optical performance analysis revealed that the modulation transfer function (MTF) degradation was maintained below 2% compared to the ideal system. The results confirm the feasibility and effectiveness of the proposed thermal design and analysis methodology in maintaining the stringent thermo-optical performance required for MHIs on inclined-LEO platforms.