基于地面试验的嫦娥五号月球矿物光谱分析仪数据质量分析

Experimental Ground Validation of Spectral Quality of the Chang'E-5 Lunar Mineralogical Spectrometer

探月工程三期项目将完成"绕、落、回"三个阶段中的采样返回任务,将在未来发射嫦娥五号(CE-5)探测器,执行月面着陆、采样并返回地球的任务。嫦娥五号月球矿物光谱分析仪(LMS)是探月工程三期重要的数据来源,通过LMS光谱数据分析识别月球表面物质的矿物组成,包括含水矿物,同时有助于判断岩石类型,辅助地层学分析。为月球的形成过程、月球地质演变及岩石-水交互作用的研究提供数据支撑。相比于嫦娥三号红外成像光谱仪,LMS将光谱范围从450～2 400nm扩展到了480～3 200nm,除了能探测月球表面主要矿物辉石、橄榄石等,还可以探测3 000nm附近的羟基吸收峰特征,为月球表面是否存在"水"提供强有力的证据。此外,嫦娥五号月面工作任务将获取月表以下物质,LMS可以对月表采样前后的采样区域进行光谱探测,比较不同深度、不同风化程度下的月壤光谱特征,且与后期返回样品的实验室光谱对比分析。为保证LMS月面数据的可靠性,在探测器发射之前开展了LMS地面验证试验,采用多种矿物及矿物混合样品,在不同试验环境下获取LMS的探测数据,分析研究LMS的矿物成分探测能力,并结合标准比对仪器光谱进行光谱质量分析。计算了所有实验样品的光谱不确定度参数。除了具有低反射率的钛铁矿外,所有样品都具有高质量的光谱数据。同时,在相同条件下,LMS光谱特征与标准比对仪器得到的光谱数据相一致,表明LMS整体数据质量高。

As the last stage of China’s Chang’e(CE)lunar program,the Chang’e-5 lunar rover will land on the surface of moon,obtain lunar samples and then return back to Earth.The Lunar Mineralogical Spectrometer(LMS)is one of CE-5’s onboard payloads,which is an important data source for the lunar exploration project.LMS spectral data is used to identify the composition of lunar minerals to aid in rock classification and stratigraphic analysis-all of which provide data required to support research on moon formation,geologic evolution and rock-water interactions.Compared with the CE-3 VIS/NIR imaging spectrometer(VNIS),the CE-5 LMS extends the spectral range from 450~2 400 to 480~3 200 nm.In addition to identifying the major minerals such as pyroxene and olivine,it can also detect absorption peaks around 3 000 nm characteristic of hydrous minerals.In addition,Chang’e-5 will sample thematerialbelow the surface of the moon,and LMS can detect the area before and after sampling,to analyze the spectral characteristics of lunar soil under different depths and weathering degrees,then compared with the laboratory spectra of the later return samples.In order to ensure the reliability of LMS lunar data,a pre-flight LMS ground validation experiment was carried out,using a variety of minerals and mineral mixed samples,collecting the detection data of LMS under different test environment,combining with a standard instrument to analyze the spectral quality.In this paper,spectral uncertainty parameters of all experiment samples were calculated and evaluated.Moreover,the LMS spectral data were consistent with those simultaneously obtained from standard comparison spectrometers under the same conditions,indicating that LMS could effectively identify the spectral profile and absorption peak of the targets.