Mineral Abundances Inferred From In Situ Reflectance Measurements of Chang'E‐4 Landing Site in South Pole‐Aitken Basin

Hu, Xiangming; Ma, Pei; Yang, Yazhou; Zhu, M. H.; Jiang, Te; Lucey, P. G.; Sun, Lingzhi; Zhang, Hao; Li, Chunlai; Xu, Rui; He, Zhiping; Hong, Lin; Huang, C. Julia; Sun, Yuxue

doi:10.1029/2019gl084531

Cited by 50 publications

(50 citation statements)

References 36 publications

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“…The higher FeO contents of the regolith at the landing site of Chang'E-4 suggest a deeper origin (e.g., Warren, 1990), probably from the lower crust or even the upper mantle. This is consistent with the recent studies (Gou et al, 2019;Hu et al, 2019;Li, Liu, et al, 2019;Lin et al, 2019) that the surface materials at the CE-4 landing site could originate from the lunar deep. The mineral fractions in these recent studies (Gou et al, 2019;Hu et al, 2019;Li, Liu, et al, 2019;Lin et al, 2019) are inconsistent, exhibiting the systematic biases of the different approaches.…”

Section: Journal Of Geophysical Research: Planetssupporting

confidence: 93%

In Situ Photometric Experiment of Lunar Regolith With Visible and Near‐Infrared Imaging Spectrometer On Board the Yutu‐2 Lunar Rover

Lin

Yang

et al. 2020

JGR Planets

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China's Chang'E‐4 (CE‐4) mission successfully landed in Von Kármán crater within South Pole‐Aitken basin of the Moon. The Visible and Near‐Infrared Imaging Spectrometer (VNIS) on board Yutu‐2 rover investigated the photometric properties of lunar regolith. Seven VNIS measurements were conducted on a small lunar surface with a diameter <5 m by the rover rotating at the center, with the phase angles from 39.6 to 97.1° obtained in the similar observational geometry of solar altitude and observation angle. The phase function, which varies in different wavelength, is derived using a third‐order polynomial fitting, in combination with the calibration and comparison of orbital/in situ VNIS data at the Chang'E‐4 landing site and the same regions. After the photometrical correction of the spectra with the phase function, the derived FeO contents and optical maturity parameters of the regolith reduce much of their deviations, which is consistent with the homogeneity of the regolith and hence demonstrates the significance of the photometric correction on the VNIS spectra.

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Section: Journal Of Geophysical Research: Planetssupporting

confidence: 93%

In Situ Photometric Experiment of Lunar Regolith With Visible and Near‐Infrared Imaging Spectrometer On Board the Yutu‐2 Lunar Rover

Lin

Yang

et al. 2020

JGR Planets

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“…tan δ = 10 0.440ρ−2.943 (6) The tanδ is the loss tangent which represents the ratio of the imaginary part of the dielectric constant to its real part. The density of lunar regolith is shown in Figure 14.…”

Section: Properties Computationmentioning

confidence: 99%

“…SPA basin is the broadest basin on the Moon. This ancient basin was born from asteroid impacts 4 billion years ago, recording the evolutionary history of the far side of the Moon, and is of great significance for researching the internal materials and structures of the Moon [4][5][6]. Von Kármán crater is one of the primary craters in the SPA basin, with a diameter of 186 km.…”

Section: Introductionmentioning

confidence: 99%

Properties Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on 3D Velocity Spectrum of Lunar Penetrating Radar

et al. 2020

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The Chinese Chang’E-4 mission for moon exploration has been successfully completed. The Chang’E-4 probe achieved the first-ever soft landing on the floor of Von Kármán crater (177.59°E, 45.46°S) of the South Pole-Aitken (SPA) basin on January 3, 2019. Yutu-2 rover is mounted with several scientific instruments including a lunar penetrating radar (LPR), which is an effective instrument to detect the lunar subsurface structure. During the interpretation of LPR data, subsurface velocity of electromagnetic waves is a vital parameter necessary for stratigraphic division and computing other properties. However, the methods in previous research on Chang’E-3 cannot perform velocity analysis automatically and objectively. In this paper, the 3D velocity spectrum is applied to property analysis of LPR data from Chang’E-4. The result shows that 3D velocity spectrum can automatically search for hyperbolas; the maximum value at velocity axis with a soft threshold function can provide the horizontal position, two-way reflected time and velocity of each hyperbola; the average maximum relative error of velocity is estimated to be 7.99%. Based on the estimated velocities of 30 hyperbolas, the structures of subsurface properties are obtained, including velocity, relative permittivity, density, and content of FeO and TiO2.

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“…We started the data reduction from the radiometric calibrated radiance data. To obtain the absolute reflectance (defined as reflectance factor in Hapke, 2012), we used the solar irradiance (Gueymard, 2004) calibration method (see Text S1 for detail) (Zhang et al, 2015;Hu et al, 2019;Lin et al, 2019).…”

Section: Absolute Reflectancementioning

confidence: 99%

The Effects of Viewing Geometry on the Spectral Analysis of Lunar Regolith as Inferred by in situ Spectrophotometric Measurements of Chang'E‐4

Yang

Lin

Liu

et al. 2020

Geophysical Research Letters

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The visible and near-infrared imaging spectrometer on board the Yutu-2 rover of Chang'E-4 mission has conducted 2 sets of spectrophotometric measurements at two sites on its 10 th lunar day. At each site, the reflectance spectra were measured on the same lunar regolith at different geometric configurations. The experiments reveal an increasing trend of the spectral reddening effect with the increasing phase angles, which may cause significant uncertainties on interpreting the maturity of the lunar regolith. Furthermore, the phase angles have significant effects on the 2-μm band center and the 1-μm band depth of the spectra, consequently on the estimation of mineral composition of the regolith. Finally, the derived average Hapke parameters using the in situ spectrophotometric measurements provide important ground-truth for remote sensing observations. Plain Language Summary Olivine, pyroxenes and plagioclase, the major constituent minerals of the surface of the Moon, have diagnostic absorption features in their visible and near-infrared reflectance spectra. These features, including the wavelength position of the absorption band center and the depth of the absorption band, can be used to identify the mineralogy of the observed surface. The slope of the reflectance spectral curve is another feature that can be used to describe the degree of how the surface materials interact with space environment. The Yutu-2 rover on board the China's Chang'E-4 mission has been equipped with a visible to near-infrared spectrometer, to carry out in situ spectral measurements at varied illumination and azimuth angles. These measurements provided us an excellent chance to study the effects of measurement angles on these spectral features, which can help us better understand the mineralogical information of lunar surface.

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Mineral Abundances Inferred From In Situ Reflectance Measurements of Chang'E‐4 Landing Site in South Pole‐Aitken Basin

Cited by 50 publications

References 36 publications

In Situ Photometric Experiment of Lunar Regolith With Visible and Near‐Infrared Imaging Spectrometer On Board the Yutu‐2 Lunar Rover

In Situ Photometric Experiment of Lunar Regolith With Visible and Near‐Infrared Imaging Spectrometer On Board the Yutu‐2 Lunar Rover

Properties Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on 3D Velocity Spectrum of Lunar Penetrating Radar

The Effects of Viewing Geometry on the Spectral Analysis of Lunar Regolith as Inferred by in situ Spectrophotometric Measurements of Chang'E‐4

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