模拟月壤发射率光谱测量实验及精度评定

基于月球样品反射光谱的月表矿物识别和成分反演能力受到月球环境的严重影响，仅限于月球表面5％的成熟度较低的区域。相比之下，包含大量硅酸盐矿物的月球样品发射光谱不仅光谱特征明显，而且受月表大气、温差和真空等环境的影响较小，是研究月表成分和物理特性的新途径。因此，对于嫦娥五号月球探测器采集的月球实地样品的发射光谱测量不仅可用于月表硅酸盐类矿物的成分分析，而且可以作为遥感研究中可见光-近红外光谱的有效补充。但是，实验室发射光谱测量中最大的难题是寻找最佳的实验方法和仪器，以便获得准确可靠的光谱数据。研究以模拟月壤样品为测量对象，分别在实验室大气、氮气冷背景和模拟真空环境中，利用TurboFT 102F和Bruker VERTEX 70V两种仪器，设计和实施了傅里叶光谱法、独立黑体法和反射率法三种发射率测量实验，并利用误差传播定律和已有Apollo样品发射率光谱对实验获得的发射率光谱进行了精度分析与评定。发现在异常复杂和困难的模拟月球真空测量环境构建完成之前，密闭实验室环境中的反射率法发射率光谱特征最明显，测量精度最高，可以作为目前月球样品发射率光谱测量的最佳选择。研究希望能为嫦娥五号采集的月球样品发射率光谱测量实验提供理论基础和技术参数。

Simulated Lunar Soil Emissivity Spectrum Measurement Experiment and Accuracy Valuation

The minerals identification and component retrieval obtained from reflectance spectrum of lunar samples were greatly affected by the environment of lunar surface，and had been applied to approximately 5% of the lunar surface where lunar soil was immature. In contrast, the emission spectrum of lunar samples which is mainly composed of silicate minerals not only had obvious spectral characteristics, but also had little influence by the lunar’s atmosphere, temperature difference and vacuum. Thus a new approach to study the component and physical properties of lunar surface was offered. In the future, the emission spectrum of lunar samples collected by Chang’e 5 detector can be used to extract the compositional analysis of silicate minerals which are the main components of lunar crust. And it is important supplement to visible-near infrared spectrum in remote sensing study. However, the greatest challenge in the laboratory emissivity measurement is finding out the best measuring methods and instruments in order to obtain accurate and reliable spectrum data. In this study, using TurboFT 102F and Bruker VERTEX 70V, based on fourier infrared spectroscopy method, independent blackbody method and reflectivity method, the emission spectrums of simulated lunar soil were measured under natural laboratory, the nitrogen cold background and vacuum environment. The numerical accuracy of emissivity spectrums was analyzed and evaluated using the error propagation law or the thermal infrared emissivity spectra of Apollo samples. The study found that the reflectivity emission spectral characteristics were the most obvious and reflectivity emissivity spectral values in which measurement accuracy was the highest in the three emission spectrum measurement methods. Thus reflectivity method under sealed laboratory environment is the best choice for lunar sample emission spectrum measurement now before the simulate lunar vacuum environment is built. We hope that research and analysis results of the paper can provide a theoretical basis and technical reference for emissivity spectrum measurement of Chang’e 5 sample.