热真空环境适应性是空间光学遥感仪器的关键性能之一，对超光谱CO₂监测仪的复原光谱精度尤为重要。基于空间外差干涉技术原理，采用理论分析和试验手段对仪器热真空环境适应性进行了讨论。理论分析了热真空环境对准直光束发散角、扩视场空间外差干涉仪组件基频波长、成像镜头离焦和缩放比等因素的改变对复原光谱的影响，并基于CS-800型热真空模拟设备开展了测量实验。实验结果表明，理论分析得到的系统基频波长与实验数据吻合，复原光谱廓线形状与理论分析一致。当干涉仪组件均采用融石英(SiLiCa)，热控精度优于1.1 ℃时，仪器可具有0.01 nm的光谱稳定度，该分析为空间外差干涉光谱仪各功能组件的热控要求、地基常压条件下基频的选定等问题提供了理论依据。

Thermal-vacuum environment adaptability is one of the key performances of space optical instru-ments, especially for hyper-spectral instrument, and spatial heterodyne spectrometer (SHS) should provide high spectral stability for the detection of atmosphere CO₂. Based on the research of the spatial heterodyne interfer-ence principle, simulation test in thermal-vacuum environment and quantitative analyses are carried out. The re-lationship among environment changes and the divergence half-angle of collimating lens, Littrow wavelength of field widened interferometer, different defocusing amount and pantograph ratio of imaging lens are analyzed. In order to verify the theoretical analysis, thermal-vacuum experiment is performed. The results show that the spec-tral deviation and profile are matched with theoretical analysis, and spectral stability is less than ±0.01 nm under the temperature from 19 ℃ to 21.2 ℃ by the substrates made of fused Silica (Corning 7980 0F). Quantitative analyses provide theoretical basis for the thermal control requirement and Littrow wavelength selection in normal atmospheric pressure.