Numerical Simulations of the Lunar Penetrating Radar and Investigations of the Geological Structures of the Lunar Regolith Layer at the Chang’E 3 Landing Site

Ding, Chunyu; Su, Yan; Xing, Shu; Dai, Shun; Xiao, Yuan; Feng, Jianqing; Liu, Danqing; Li, Chunlai

doi:10.1155/2017/3013249

Cited by 10 publications

(11 citation statements)

References 14 publications

(17 reference statements)

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“…Similar procedure has been applied for the CE‐3 LPR data in previous studies (e.g., Lai et al, 2017). Based on a regolith model that contains stochastically distributed relative permittivity around a given average value (Ding et al, 2017), the effect of h LPR on the derived relative permittivity based on hyperbolic echo patterns is constrained to be ~13% (see Figure S8), which is comparable with the inherent uncertainty associated with the general method (Shihab & Al‐Nuaimy, 2005).…”

Section: Geological Context Data and Methodsmentioning

confidence: 99%

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Layering Structures in the Porous Material Beneath the Chang'e‐3 Landing Site

Ding

Xiao

et al. 2020

Earth and Space Science

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The lunar penetrating radar (LPR) onboard the Chinese Chang'e-3 (CE-3) mission obtained high-resolution profile data for the continuous ejecta deposits of the Ziwei crater. Geological background suggests that the continuous ejecta deposits contain few large boulders, and the ejecta deposits were largely originated from the pre-impact regolith. Using the top~50 ns of radar data, we estimate the bulk density and porosity for the ejecta deposits based on hyperbolic echo patterns in the radargram that are caused by subsurface boulders. The physical properties are close to those of typical lunar regolith. Numerous subparallel and discontinuous short layers are visible in the radargram of the continuous ejecta deposits. The dielectric coefficients of the layering structures are estimated, and their permittivity is slightly larger than that of typical lunar regolith and less than that of basaltic rocks. Cratering physics together with the geological context of this area suggest that the layering structures are most likely ground gravels and/or melt-welded breccias that were sheared due to the horizontal momentum of the impact ejecta. This interpretation is indicative of the origin of the enigmatic layering structures in regolith core samples returned by the Apollo and Luna missions. The results also highlight the importance of ejecta emplacement in shaping the structure of lunar regolith. Plain Language Summary Large discrepancies existed in previous geological interpretations using the Chang'e-3 high-frequency LPR data. A comprehensive review of previous studies that used the Chang'e-3 radar data noticed that most previous studies agree that the top~50 ns of the radargram is restricted within the continuous ejecta deposits of the Ziwei crater. Analyses for the stratigraphy of the landing site suggested that the continuous ejecta deposits were largely composed by pre-impact regolith. Using the high-frequency LPR data, we reconstructed the depth profiles of physical parameters (i.e., relative permittivity, bulk density, and porosity) for the continuous ejecta deposits of the Ziwei crater, which are similar with those of typical lunar regolith. Many subparallel and discontinuous layers are observed in the radargram, which were not deciphered before. We carried out numerical simulations to study the nature of the layering features. Results suggest that these structures have a permittivity slightly larger than that of typical lunar regolith. Geological context of the landing site suggested that the layering structures are likely shear bands within the continuous ejecta deposits, and they may be composed by ground rock fragments and/or melt-welded breccia, which were laterally deformed due to the horizontal momentum of the ejecta deposits.

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Section: Geological Context Data and Methodsmentioning

confidence: 99%

“…Similar modeling work has been carried out to analyze the thickness and interior structures of lunar regolith at the CE-3 landing site, and possible dielectric permittivity of the subsurface materials was derived using 10.1029/2019EA000862 inverse calculation (Ding et al, 2017;Lai et al, 2017;J. Li et al, 2017).…”

Section: Numerical Simulation Of the Lprmentioning

confidence: 99%

Layering Structures in the Porous Material Beneath the Chang'e‐3 Landing Site

Ding

Xiao

et al. 2020

Earth and Space Science

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“…Thus, we established two different stochastic models with fewer and more horizontal disturbances, respectively, as shown in Figure 4c,d. Here, we applied the stochastic modeling method to simulate the lunar regolith, which is closer to the real situation according to the statistic [22,41]. Previous works have applied this method both in the GPR and LPR numerical simulations [41][42][43].…”

Section: Stochastic Modelingmentioning

confidence: 99%

A Novel Approach for Permittivity Estimation of Lunar Regolith Using the Lunar Penetrating Radar Onboard Chang’E-4 Rover

Wang

Ding

et al. 2021

Remote Sensing

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Accurate relative permittivity is essential to the further analysis of lunar regolith. The traditional hyperbola fitting method for the relative permittivity estimation using the lunar penetrating radar generally ignored the effect of the position and geometry of antennas. This paper proposed a new approach considering the antenna mounting height and spacing in more detail. The proposed method is verified by numerical simulations of the regolith models. Hence the relative permittivity of the lunar regolith is calculated using the latest high-frequency radar image obtained by the Yutu-2 rover within the first 24 lunar days. The simulation results show that the relative permittivity is underestimated when derived by the traditional method, especially at the shallow depth. The proposed method has improved the accuracy of the estimated lunar regolith relative permittivity at a depth of 0–3 m, 3–6 m, and 6–10 m by 35%, 14%, and 9%, respectively. The thickness of the lunar regolith at the Chang’E 4 landing site is reappraised to be 11.1 m, which improved by ~8% compared with previous studies.

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“…However, in the past, the lunar regolith has usually been assumed to be a uniform layered medium [4][5][6][7][8]. A series of recent studies have shown that the lunar regolith is essentially inhomogeneous [9][10][11][12][13][14][15][16] but the specific structural characteristics of the lunar regolith are still unclear.…”

Section: Introductionmentioning

confidence: 99%

“…Most traditional numerical simulations of LPR data assume layered models [4][5][6][7][8] and cannot well represent the heterogeneity of the lunar regolith. Recently, several works have considered the heterogeneity [9][10][11][12][13][14][15] but do not take typical models into account (e.g., cracks and ejecta). Lv et al [16] constructed four typical models and performed numerical simulations using the time-domain finite-difference method, which can better present the wave propagation in the lunar regolith with strong heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

Self-Organization Characteristics of Lunar Regolith Inferred by Yutu-2 Lunar Penetrating Radar

Zhang

et al. 2021

Remote Sensing

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Most previous studies tend to simplify the lunar regolith as a homogeneous medium. However, the lunar regolith is not completely homogeneous, because there are weak reflections from the lunar regolith layer. In this study, we examined the weak heterogeneity of the lunar regolith layer using a self-organization model by matching the reflection pattern of both the lunar regolith layer and the top of the ejecta layer. After a series of numerical experiments, synthetic results show great consistency with the observed Chang’E-4 lunar penetrating radar data and provide some constraints on the range of controlling parameters of the exponential self-organization model. The root mean square permittivity perturbation is estimated to be about 3% and the correlation distance is about 5–10 cm. Additionally, the upper layer of ejecta has about 1–2 rocks per square meter, and the rock diameter is about 20–30 cm. These parameters are helpful for further study of structural characteristics and the evolution process of the lunar regolith. The relatively small correlation distance and root mean square perturbation in the regolith indicate that the regolith is mature. The weak reflections within the regolith are more likely to be due to structural changes rather than material composition changes.

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Numerical Simulations of the Lunar Penetrating Radar and Investigations of the Geological Structures of the Lunar Regolith Layer at the Chang’E 3 Landing Site

Cited by 10 publications

References 14 publications

Layering Structures in the Porous Material Beneath the Chang'e‐3 Landing Site

Layering Structures in the Porous Material Beneath the Chang'e‐3 Landing Site

A Novel Approach for Permittivity Estimation of Lunar Regolith Using the Lunar Penetrating Radar Onboard Chang’E-4 Rover

Self-Organization Characteristics of Lunar Regolith Inferred by Yutu-2 Lunar Penetrating Radar

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