ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars
ChemCam passive reflectance spectroscopy of surface materials at the Curiosity landing site, Mars
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好奇号火星着陆点表面材料的 ChemCam 被动反射光谱
DOI：
10.1016/j.icarus.2014.02.028
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发表时间：
2015
期刊：
影响因子：
3.2
通讯作者：
R. Wiens
中科院分区：
文献类型：
--
作者：
Jeffrey R. Johnson;J. Bell;S. Bender;D. Blaney;E. Cloutis;L. Deflores;B. Ehlmann;O. Gasnault;B. Gondet;K. Kinch;M. Lemmon;S. Mouélic;S. Maurice;M. Rice;R. Wiens
火星科学实验室（MSL） ChemCam仪器上的光谱仪以被动模式记录火星表面的可见/近红外（400 - 840nm）辐射。利用机载ChemCam校准目标的外壳作为反射率标准，我们开发了收集、校准和减少辐射观测到相对反射率的方法。这些测量准确地再现了火星车上其他校准目标的已知反射光谱，并代表了火星着陆平台上最高的空间分辨率（0.65 mrad）和光谱采样（<1 nm）可见/近红外反射光谱。地表岩石和土壤的相对反射光谱与轨道观测和MSL Mastcam相机的多光谱数据相匹配。对MSL第一年采集的2000多个光谱的波段深度、光谱斜率和反射率比的初步分析表明，至少有六种光谱类型的材料可以通过铁元素和铁元素的变化来区分。ChemCam光谱与矿物和火星模拟物质的实验室光谱的初步比较表明，它们与古拉贡石土壤相似，并且在一些深色岩石中有正辉石的迹象。富含镁的“隆起脊”倾向于表现出明显的近红外斜坡。火星材料在<600 nm处的铁吸收下降，在拉丝岩石和钻孔尾矿中被大大抑制，这与它们更含铁的性质一致。硫酸钙脉显示出最高的相对反射率，但由于残余尘埃的影响，仍然相对呈红色。在着陆点周围的“爆炸区”内取样的岩石上，这种尘埃总体上不太明显。这些样本可能受到了着陆推进器的影响，它部分地除去了无处不在的灰尘涂层。ChemCam被动测量也记录了在任务的第一年校准目标上增加的灰尘涂层。正在进行的模拟和校正尘埃成分的工作应该会改善相对反射光谱的校准。这将是有用的，因为在探测器未来对夏普山底部附近的含赤铁矿、硫酸盐和层状硅酸盐的物质进行检测时，这些物质的光谱活性在400-840纳米范围内。
The spectrometers on the Mars Science Laboratory (MSL) ChemCam instrument were used in passive mode to record visible/near-infrared (400–840 nm) radiance from the martian surface. Using the onboard ChemCam calibration targets’ housing as a reflectance standard, we developed methods to collect, calibrate, and reduce radiance observations to relative reflectance. Such measurements accurately reproduce the known reflectance spectra of other calibration targets on the rover, and represent the highest spatial resolution (0.65 mrad) and spectral sampling (<1 nm) visible/near-infrared reflectance spectra from a landed platform on Mars. Relative reflectance spectra of surface rocks and soils match those from orbital observations and multispectral data from the MSL Mastcam camera. Preliminary analyses of the band depths, spectral slopes, and reflectance ratios of the more than 2000 spectra taken during the first year of MSL operations demonstrate at least six spectral classes of materials distinguished by variations in ferrous and ferric components. Initial comparisons of ChemCam spectra to laboratory spectra of minerals and Mars analog materials demonstrate similarities with palagonitic soils and indications of orthopyroxene in some dark rocks. Magnesium-rich “raised ridges” tend to exhibit distinct near-infrared slopes. The ferric absorption downturn typically found for martian materials at <600 nm is greatly subdued in brushed rocks and drill tailings, consistent with their more ferrous nature. Calcium-sulfate veins exhibit the highest relative reflectances observed, but are still relatively red owing to the effects of residual dust. Such dust is overall less prominent on rocks sampled within the “blast zone” immediately surrounding the landing site. These samples were likely affected by the landing thrusters, which partially removed the ubiquitous dust coatings. Increased dust coatings on the calibration targets during the first year of the mission were documented by the ChemCam passive measurements as well. Ongoing efforts to model and correct for this dust component should improve calibration of the relative reflectance spectra. This will be useful as additional measurements are acquired during the rover’s future examinations of hematite-, sulfate-, and phyllosilicate-bearing materials near the base of Mt. Sharp that are spectrally active in the 400–840 nm region.
影响因子：
56.9
作者：
Meslin, P-Y.;Gasnault, O.;Yingst, A.
通讯作者：
Yingst, A.
影响因子：
3.2
作者：
Anderson, Ryan;Bridges, J. C.;Vaniman, D.
通讯作者：
Vaniman, D.
影响因子：
56.9
作者：
Blake, D. F.;Morris, R. V.;Sarrazin, P.
通讯作者：
Sarrazin, P.