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.

Agile Earth observation satellites (AEOSs) are a new generation of Earth observation satellites. To promote the aerospace application of non-track active imaging with a large scope and long duration for AEOSs, an improved numerical analysis method of on-orbit dynamic infrared radiation is proposed in this paper. Based on a model of the spaceborne component surfaces in the spherical coordinate system, the thermal radiation factors are derived. Then, a case of a non-track active imaging mission with an optical axis trajectory of 6000 km and a latitude span of 40° was analyzed and investigated, and the results demonstrate strong nonlinearity with large amplitude and fast rate variation, and the average incident heat flux of most components shows a higher level than that of conventional subsatellite imaging. Notably, this study provides a crucial theoretical basis of boundary conditions for the thermal control system and the heat radiator design method for optical payloads.