New Insight Into Lunar Regolith‐Forming Processes by the Lunar Rover Yutu‐2

Lin, Honglei; Lin, Yangting; Yang, Wei; He, Zhiping; Hu, Sen; Wei, Yong; Xu, Rui; Zhang, Jinhai; Liu, Xiaohui; Yang, Jianfeng; Xing, Yan; Yu, Chengwu; Zou, Yongliao

doi:10.1029/2020gl087949

Cited by 31 publications

(22 citation statements)

References 41 publications

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“…The CE-4 LPR is a dual-frequency ground penetrating radar (GPR) system, operating at 60 MHz (low-frequency) with a frequency band of 40~80 MHz and 500 MHz (highfrequency) with frequency band of 250~750 MHz [11,21]. The CH-2 radar data were collected during the first 16 lunar days along the Yutu-2 s traverse of about 425 m, as shown in Figure 1, which is consistent with the results acquired by Lin et al [22]. To reveal the near-surface structure of the regolith, we processed and interpreted the high-frequency LPR data (CH-2A and CH-2B) by excluding the effects of the electromagnetic coupling with the rover's metallic body.…”

Section: Lpr Data Processingsupporting

confidence: 82%

Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis

Song

Zhang

et al. 2020

Remote Sensing

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The Lunar Penetrating Radar (LPR) onboard the Yutu-2 rover from China’s Chang’E-4 (CE-4) mission is used to probe the subsurface structure and the near-surface stratigraphic structure of the lunar regolith on the farside of the Moon. Structural analysis of regolith could provide abundant information on the formation and evolution of the Moon, in which the rock location and property analysis are the key procedures during the interpretation of LPR data. The subsurface velocity of electromagnetic waves is a vital parameter for stratigraphic division, rock location estimates, and calculating the rock properties in the interpretation of LPR data. In this paper, we propose a procedure that combines the regolith rock extraction technique based on local correlation between the two sets of LPR high-frequency channel data and the common offset semblance analysis to determine the velocity from LPR diffraction hyperbola. We consider the heterogeneity of the regolith and derive the relative permittivity distribution based on the rock extraction and semblance analysis. The numerical simulation results show that the procedure is able to obtain the high-precision position and properties of the rock. Furthermore, we apply this procedure to CE-4 LPR data and obtain preferable estimations of the rock locations and the properties of the lunar subsurface regolith.

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Section: Lpr Data Processingsupporting

confidence: 82%

Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis

Song

Zhang

et al. 2020

Remote Sensing

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“…We speculated that the bright spot area was not likely caused by the stray light introduced by the specular reflection of the MLI. In a previous study, researchers analyzed data from the ninth lunar day detection and reported the presence of glass in the pit fragments [11]. Consequently, we considered that this abnormally bright region in the VIS/NIR images may be the micro specular reflection of the glass.…”

Section: Effectmentioning

confidence: 98%

“…Next, we smoothed the reflectance data by using the cubic splines method with a smoothing parameter of 0.9999 [26]. Furthermore, we compared the reflectance through normalization (R i−normalization = R i /∑ i=n i=1 R i [11], where i is the number of bands). According to Figure 10, the F46 film exhibits a wide absorption at 750-850 nm, whereas the average reflectance spectrum of the bright spot region does not exhibit such an absorption feature.…”

Section: Effectmentioning

confidence: 99%

“…Notably, because of the solar incidence from the front of the rover, the impact of scattered light from the MLI could not be excluded in this area. The effect of MLI may also be superimposed on the glass spectra with high albedo features, resulting in a broad absorption feature near 800 nm, as described in Lin [11]. In general, if notably bright areas are observed in a VIS/NIR image of the VNIS, it must be analyzed considering three aspects to established the influence of the specular reflection of the MLI.…”

Section: Effectmentioning

confidence: 99%

“…However, no studies have been conducted to examine the effects of large-area shadow occlusion caused by the illumination angle as well as the orientation of the rover. In the CE-4 photometric analysis, Lin found differences between the data characteristics and the minerals, and speculated that they might be influenced by stray illumination introduced by the MLI [11]. In general, when the CE-4 Yutu-2 rover advances, the VNIS simultaneously selects suitable observation points for spectral detection [3].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Lunar Complex Illumination on In Situ Measurements Obtained Using Visible and Near-Infrared Imaging Spectrometer of Chang’E-4

Wang

Lin

et al. 2021

Remote Sensing

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In-situ measurements of the spectral information on the lunar surface are of significance to study the geological evolution of the Moon. China’s Chang’E-4 (CE-4) Yutu-2 rover has conducted several in-situ spectral explorations on the Moon. The visible and near-infrared imaging spectrometer (VNIS) onboard the rover has acquired a series of in-situ spectra of the regolith at the landing site. In general, the mineralogical research of the lunar surface relies on the accuracy of the in-situ data. However, the spectral measurements of the Yutu-2 rover may be affected by shadows and stray illumination. In this study, we analyzed 106 CE-4 VNIS spectra acquired in the first 24 lunar days of the mission and noted that six of these spectra were affected by the shadows of the rover. Therefore, a method was established to correct the effects of the rover shadow on the spectral measurements. After shadow correction, the FeO content in the affected area is corrected to 14.46 wt.%, which was similar to the result calculated in the normal regolith. Furthermore, according to the visible images, certain areas of the explored sites were noted to be unusually bright. Considering the reflectance, geometric information, and shining patterns of the multi-layer insulation (MLI), we examined the influence of the specular reflection of the MLI on the bright spot regionsd , and found that the five sets of data were likely not affected by the specular reflection of the MLI. The results indicated that the complex illumination considerably influences the in situ spectral data. This study can provide a basis to analyze the VNIS scientific data and help enhance the accuracy of interpretation of the composition at CE-4 landing sites.

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Lunar Mineralogical Spectrometer on Chang’E-5 Mission

Yuan

et al. 2022

Space Sci Rev

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The Lunar Mineralogical Spectrometer (LMS) is one of the main payloads on the Chang’E-5 (CE-5) lunar probe, belonging to the China Lunar Exploration Program. The scientific objective of the LMS is to explore the mineralogical composition and search for evidence of -OH/H2O in the sampling area. The LMS consists of an optomechanism unit, a dustproof calibration unit (DPCU) and an electronic unit. The LMS is installed on the lander about 1.4-m above the lunar surface, the field of view (FOV) is $4.17\times 4.17^{\circ }$ 4.17 × 4.17 ∘ , the instant FOV of the visible imaging channel is 0.28 mrad, and the typical spatial resolution is 0.56 mm/pixel @ 2 m distance. The rotation range of the 2D scanner is $\pm 22.5^{\circ}$ ± 22.5 ∘ along the azimuth axis and $0\sim 30^{\circ }$ 0 ∼ 30 ∘ along the elevation axis, making it possible to observe the sampling area or to select important observing targets. The dispersing beam uses acousto-optic tunable filters, and target detection is performed with a 2D scanner. The LMS acquires spectral imaging information covering 480–950 nm, and reflectance spectra of 900–3,200-nm, both at a 5-nm/band sampling interval. The spectral resolution is $2.4\sim 9.4\text{ nm}$ 2.4 ∼ 9.4 nm in the visible and near-infrared channels and $7.6\sim 24.9\text{ nm}$ 7.6 ∼ 24.9 nm in the short–medium-wave infrared channel. The LMS has a 588-band detection capability designed for fine spectral observation of sampling points and wields a 20-band full-view multi-spectral mode to observe candidate areas prior to sampling. The DPCU of the LMS is integrated with a calibration diffuser that is used for in-flight calibration on the lunar surface using solar irradiation, thus improving the quantitative level of scientific data.

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New Insight Into Lunar Regolith‐Forming Processes by the Lunar Rover Yutu‐2

Cited by 31 publications

References 41 publications

Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis

Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis

Effect of Lunar Complex Illumination on In Situ Measurements Obtained Using Visible and Near-Infrared Imaging Spectrometer of Chang’E-4

Lunar Mineralogical Spectrometer on Chang’E-5 Mission

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