Special Issue "Lunar Remote Sensing and Applications"

A special issue of Remote Sensing (ISSN 2072-4292). This special issue belongs to the section "Satellite Missions".

Deadline for manuscript submissions: 30 June 2021.

Special Issue Editors

Prof. Dr. Shengbo Chen
E-Mail
Guest Editor
College of Geo-exploration Science and Technology, Jilin University, No. 938 XiMinZhu Street, Chaoyang Distract, Changchun 130026, China
Interests: coastal geology and geomorphology; coastal geological hazards; remote sensing
Special Issues and Collections in MDPI journals
Prof. Lin Li
E-Mail Website
Guest Editor
Department of Earth Sciences, Indiana University Purdue University Indianapolis, 723 West Michigan Street, Indianapolis, IN 46202, USA
Interests: environmental remote sensing; image processing; data analysis
Special Issues and Collections in MDPI journals
Prof. Dr. Yuanzhi Zhang
E-Mail
Guest Editor
Key Lab of Lunar Science and Deep-exploration, Chinese Academy of Sciences, No. 20A Datun Road, Chaoyang Distract, Beijing 100101, China
Interests: remote sensing; lunar and planetary science; Mars and Venus geology; environmental remote sensing; image processing
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The exploration of the Moon has generated a large volume of various datasets for addressing scientifically important questions on lunar geology, including the origin of the Moon, the origin and evolution of the lunar crust and mantle, the compositional structure of the lunar interior, lunar volcanism and impact cratering processes, regolith evolution and mixing dynamics, space weathering, as well as searching for and utilizing resources for a human future presence on the Moon. Analysis of the rock samples returned by the Apollo and Luna missions has resulted in numerous important discoveries and observations revolving around these scientific questions. However, the lunar samples returned to Earth so far have very limited spatial coverage, and extrapolation of the sample-based geological context to the global or regional scale surface setting of the Moon heavily relies on remote sensing datasets acquired by lunar spacecraft.

Lunar remote sensing images are mainly composed of multi- and hyper-spectral datasets in the visible (VIS), near-infrared (NIR), and shortwave infrared (SWIR), which are sensitive to the mineralogical composition of the lunar surface because of the spectrally diagnostic absorption features of major minerals (e.g. olivine, clinopyroxene, orthopyroxene, ilmenite, plagioclase) and different glasses on the Moon. On the other hand, thermal infrared (TIR) and passive microwave data are definitely necessary for mapping substrate physical properties (temperature, regolith size, thickness and layering) and chemical compositions, which are helpful for refining the classification of the substrate regolith and mare basaltic units and for mapping lunar faults and tectonic units.

Over the past decades, a wealth of remotely-sensed photographic and spectroscopic data have been collected by various lunar missions such as Clementine, Small Missions for Advanced Research in Technology-1 (SMART-1), Lunar Reconnaissance Orbiter, SELENE, Chang’E I-III, and Chandrayaan-1. Additionally, a large fleet of new lunar missions will be launched in next few years by different countries and private sectors. These previously and newly acquired remote sensing data provide unprecedented opportunities to study the Moon by the examination of new ideas and testing data analysis algorithms.

This Special Issue invites manuscripts resulting from the analysis of remote sensing datasets acquired by the latest lunar missions, as well as from lab-measured spectral data with the aim of highlighting the importance of lab spectroscopic and imaging remote sensing in studies of the Moon. The Special Issue also welcomes to manuscripts reporting research results from various observations and measurements by use of photography, X-ray, gamma-ray, gravitational, magnetic, and topographic data, which advance our current knowledge of the Moon. The topics include, but are not limited to the following:

  • Optical remote sensing and data analysis techniques for the identification and mapping of lunar regolith, mineralogy, and lithology;
  • Thermal remote sensing of physical and compositional properties of the lunar surface;
  • Microwave remote sensing of lunar subsurface structure;
  • Radiative transfer models for lunar remote sensing;
  • Integration of remote sensing data with laboratory spectral and compositional measurements;
  • Photogeological analysis of lunar terrains;
  • Photogeological analysis of lunar faults and tectonic units;
  • Photogeological analysis of lunar volcanism;
  • Photogeological analysis of impact craters, South Pole-Aitken (SPA) and other basins;
  • Remote sensing of lunar polar regions and space weathering

Prof. Dr. Shengbo Chen
Prof. Dr. Lin Li
Prof. Dr. Yuanzhi Zhang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Remote Sensing is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • The Moon
  • Remote Sensing
  • Space weathering
  • Regolith, mineral, and rock
  • Lunar crust and interior
  • Lunar volcanism and thermal history
  • Lunar faults and tectonic features
  • Impact craters and ejecta deposits
  • South Pole-Aitken (SPA) and other basins
  • Permanent shadow and ice

Published Papers (14 papers)

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Open AccessArticle
Investigating the Retention of Solar Wind Implanted Helium-3 on the Moon from the Analysis of Multi-Wavelength Remote Sensing Data
Remote Sens. 2020, 12(20), 3350; https://doi.org/10.3390/rs12203350 - 14 Oct 2020
Cited by 2 | Viewed by 848
Abstract
The Moon has a large potential for space exploration and mining valuable resources. In particular, 3He provides rich sources of non-radioactive fusion fuel to fulfill cislunar and Earth’s energy demands, if found economically feasible. The present study focuses on developing advanced techniques [...] Read more.
The Moon has a large potential for space exploration and mining valuable resources. In particular, 3He provides rich sources of non-radioactive fusion fuel to fulfill cislunar and Earth’s energy demands, if found economically feasible. The present study focuses on developing advanced techniques to prospect 3He resources on the Moon from multi-sensor remote sensing perspectives. It characterizes optical changes in regolith materials due to space weathering as a new retention parameter and introduces a novel machine learning inversion model for retrieving the physical properties of the regolith. Our analysis suggests that the reddening of the soil predominantly governs the retention, along with attenuated mafic band depths. Moreover, semi-variograms show that the spatial variability of 3He is aligned with the episodic weathering events at different timescales. We also observed that pyroclastic regoliths with high dielectric constant and increased surface scattering mechanisms exhibited a 3He abundant region. For ejecta cover, the retention was weakly associated with the dielectric contrast and a circular polarization ratio (CPR), mainly because of the 3He-deficient nature of the regolith. Furthermore, cross-variograms revealed inherent cyclicity attributed to the sequential process of weathering effects. Our study provides new insights into the physical nature and near-surface alterations of lunar regoliths that influence the spatial distribution and retention of solar wind implanted 3He. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Thermophysical Features of the Rümker Region in Northern Oceanus Procellarum: Insights from CE-2 CELMS Data
Remote Sens. 2020, 12(19), 3272; https://doi.org/10.3390/rs12193272 - 08 Oct 2020
Cited by 1 | Viewed by 1021
Abstract
The Rümker region is located in the northern Oceanus Procellarum, which has been selected as the landing and sampling region for China’s Chang’e-5 (CE-5) mission. The thermophysical features of the mare units are studied in detail using the brightness temperature (TB) maps (TB, [...] Read more.
The Rümker region is located in the northern Oceanus Procellarum, which has been selected as the landing and sampling region for China’s Chang’e-5 (CE-5) mission. The thermophysical features of the mare units are studied in detail using the brightness temperature (TB) maps (TB, normalized TB, TB difference) derived from the CE-2 microwave radiometer data. The previously interpreted geological boundaries of the Rümker region are revisited in this study according to their TB behaviors: IR1, IR2, and IR3 Rümker plateau units are combined into one single unit (IR); and a hidden unit is found on the Mons Rümker; Mare basaltic units Im1 and Em1 are combined into Em1; and Em2 is more likely the extending of Im2. Each of the previous proposed landing sites and their scientific value are summarized and reevaluated. Based on this, four landing sites are recommended in order to maximize the scientific outcome of the CE-5 mission. We suggest that the Eratosthenian-aged Em4 and Em1 units as the top priority landing site for the CE-5 mission; the age-dating results will provide important clues concerning the thermal evolution of the Moon. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Photometric Normalization of Chang’e-4 Visible and Near-Infrared Imaging Spectrometer Datasets: A Combined Study of In-Situ and Laboratory Spectral Measurements
Remote Sens. 2020, 12(19), 3211; https://doi.org/10.3390/rs12193211 - 01 Oct 2020
Cited by 1 | Viewed by 1299
Abstract
Until 29 May 2020, the Visible and Near-Infrared Imaging Spectrometer (VNIS) onboard the Yutu-2 Rover of the Chang’e-4 (CE-4) has acquired 96 high-resolution surface in-situ imaging spectra. These spectra were acquired under different illumination conditions, thus photometric normalization should be conducted to correct [...] Read more.
Until 29 May 2020, the Visible and Near-Infrared Imaging Spectrometer (VNIS) onboard the Yutu-2 Rover of the Chang’e-4 (CE-4) has acquired 96 high-resolution surface in-situ imaging spectra. These spectra were acquired under different illumination conditions, thus photometric normalization should be conducted to correct the introduced albedo differences before deriving the quantitative mineralogy for accurate geologic interpretations. In this study, a Lommel–Seeliger (LS) model and Hapke radiative transfer (Hapke) model were used and empirical phase functions of the LS model were derived. The values of these derived phase functions exhibit declining trends with the increase in phase angles and the opposition effect and phase reddening effect were observed. Then, we discovered from in-situ and laboratory measurements that the shadows caused by surface roughness have significant impacts on reflectance spectra and proper corrections were introduced. The validations of different phase functions showed that the maximum discrepancy at 1500 nm of spectra corrected by the LS model was less (~3.7%) than that by the Hapke model (~7.4%). This is the first time that empirical phase functions have been derived for a wavelength from 450 to 2395 nm using in-situ visible and near-infrared spectral datasets. Generally, photometrically normalized spectra exhibit smaller spectral slopes, lower FeO contents and larger optical maturity parameter (OMAT) than spectra without correction. In addition, the band centers of the 1 and 2 μm absorption features of spectra after photometric normalization exhibit a more concentrated distribution, indicating the compositional homogeneity of soils at the CE-4 landing site. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Spatio-Temporal Characteristics for Moon-Based Earth Observations
Remote Sens. 2020, 12(17), 2848; https://doi.org/10.3390/rs12172848 - 02 Sep 2020
Viewed by 896
Abstract
Spatio-temporal characteristics are the crucial conditions for Moon-based Earth observations. In this study, we established a Moon-based Earth observation geometric model by considering the intervisibility condition between a Moon-based platform and observed points on the Earth, which can analyze the spatio-temporal characteristics of [...] Read more.
Spatio-temporal characteristics are the crucial conditions for Moon-based Earth observations. In this study, we established a Moon-based Earth observation geometric model by considering the intervisibility condition between a Moon-based platform and observed points on the Earth, which can analyze the spatio-temporal characteristics of the observations of Earth’s hemisphere. Furthermore, a formula for the spherical cap of the Earth visibility region on the Moon is analytically derived. The results show that: (1) the observed Earth spherical cap has a diurnal period and varies with the nadir point. (2) All the annual global observation durations in different years show two lines that almost coincide with the Arctic circle and the Antarctic circle. Regions between the two lines remain stable, but the observation duration of the South pole and North pole changes every 18.6 years. (3) With the increase of the line-of-sight minimum observation elevation angle, the area of an intervisible spherical cap on the lunar surface is obviously decreased, and this cap also varies with the distance between the barycenter of the Earth and the barycenter of the Moon. In general, this study reveals the effects of the elevation angle on the spatio-temporal characteristics and additionally determines the change of area where the Earth’s hemisphere can be observed on the lunar surface; this information can provide support for the accurate calculation of Moon-based Earth hemisphere observation times. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Estimation of Noise in the In Situ Hyperspectral Data Acquired by Chang’E-4 and Its Effects on Spectral Analysis of Regolith
Remote Sens. 2020, 12(10), 1603; https://doi.org/10.3390/rs12101603 - 18 May 2020
Viewed by 871
Abstract
The Chang’E-4 (CE-4) spacecraft landed successfully on the far side of the Moon on 3 January 2019, and the rover Yutu-2 has explored the lunar surface since then. The visible and near-infrared imaging spectrometer (VNIS) onboard the rover has acquired numerous spectra, providing [...] Read more.
The Chang’E-4 (CE-4) spacecraft landed successfully on the far side of the Moon on 3 January 2019, and the rover Yutu-2 has explored the lunar surface since then. The visible and near-infrared imaging spectrometer (VNIS) onboard the rover has acquired numerous spectra, providing unprecedented insight into the composition of the lunar surface. However, the noise in these spectral data and its effects on spectral interpretation are not yet assessed. Here we analyzed repeated measurements over the same area at the lunar surface to estimate the signal–noise ratio (SNR) of the VNIS spectra. Using the results, we assessed the effects of noise on the estimation of band centers, band depths, FeO content, optical maturity (OMAT), mineral abundances, and submicroscopic metallic iron (SMFe). The data observed at solar altitudes <20° exhibit low SNR (25 dB), whereas the data acquired at 20°–35° exhibit higher SNR (35–37 dB). We found differences in band centers due to noise to be ~6.2 and up to 28.6 nm for 1 and 2 μm absorption, respectively. We also found that mineral abundances derived using the Hapke model are affected by noise, with maximum standard deviations of 6.3%, 2.4%, and 7.0% for plagioclase, pyroxene, and olivine, respectively. Our results suggest that noise has significant impacts on the CE-4 spectra, which should be considered in the spectral analysis and geologic interpretation of lunar exploration data. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
An Empirical Model to Estimate Abundance of Nanophase Metallic Iron (npFe0) in Lunar Soils
Remote Sens. 2020, 12(6), 1047; https://doi.org/10.3390/rs12061047 - 24 Mar 2020
Cited by 2 | Viewed by 872
Abstract
Lunar soils gradually become mature when they are exposed to a space environment, and nanophase metallic iron (npFe0) generates within them. npFe0 significantly changes the optical properties of lunar soils and affects the interpretation of the remotely sensed data of [...] Read more.
Lunar soils gradually become mature when they are exposed to a space environment, and nanophase metallic iron (npFe0) generates within them. npFe0 significantly changes the optical properties of lunar soils and affects the interpretation of the remotely sensed data of the lunar surface. In this study, a correlation analysis was conducted between npFe0 abundance and reflectance spectra at short wavelengths for lunar soil samples in four size groups based on their spectral and compositional data, collected by the Lunar Soil Characterization Consortium (LSCC). Results show that 540 nm single scattering albedo (SSA) of lunar soils correlates well with their corresponding npFe0 abundance for each size group of lunar soil samples. However, it is poorly correlated with npFe0 abundance when all size groups were considered because of the strong interference from grain size variation of lunar soils. To minimize the effect of grain size, the correlation of npFe0 abundance with the spectral ratio of 540 nm/810 nm SSA of all size groups for LSCC samples was calculated and results show that a higher correlation existed between them (R2 = 0.91). This ratio can serve as a simple empirical model for estimating npFe0 abundance in lunar soils. However, bias could be introduced to the estimation result when lunar soils possess a high content of agglutinitic glass and ilmenite. Our future work will focus on improving the model’s performance for these lunar soils. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Lunar Regolith Temperature Variation in the Rümker Region Based on the Real-Time Illumination
Remote Sens. 2020, 12(4), 731; https://doi.org/10.3390/rs12040731 - 22 Feb 2020
Cited by 3 | Viewed by 896
Abstract
Chang’E-5 will be China’s first sample−return mission. The proposed landing site is at the late-Eratosthenian-aged Rümker region of the lunar nearside. During this mission, a driller will be sunk into the lunar regolith to collect samples from depths up to two meters. This [...] Read more.
Chang’E-5 will be China’s first sample−return mission. The proposed landing site is at the late-Eratosthenian-aged Rümker region of the lunar nearside. During this mission, a driller will be sunk into the lunar regolith to collect samples from depths up to two meters. This mission provides an ideal opportunity to investigate the lunar regolith temperature variation, which is important to the drilling program. This study focuses on the temperature variation of lunar regolith, especially the subsurface temperature. Such temperature information is crucial to both the engineering needs of the drilling program and interpretation of future heat-flow measurements at the lunar landing site. Based on the real-time illumination, and particularly the terrain obscuration, a one-dimensional heat equation was applied to estimate the temperature variation over the whole landing region. Our results confirm that while solar illumination strongly affects the surface temperature, such effect becomes weak at increasing depths. The skin depth of diurnal temperature variations is restricted to the uppermost ~5 cm, and the temperature of regolith deeper than ~0.6 m is controlled by the interior heat flow. At such a depth, China’s future lunar exploration is adequate to measure the inner heat flow, considering the drilling depth will be close to 2 m. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Reevaluating Mare Moscoviense And Its Vicinity Using Chang’e-2 Microwave Sounder Data
Remote Sens. 2020, 12(3), 535; https://doi.org/10.3390/rs12030535 - 06 Feb 2020
Cited by 4 | Viewed by 904
Abstract
Mare Moscoviense (148°E, 27°N) is one of the few large maria on the lunar farside, with the thinnest crust and a positive gravity anomaly. In this paper, the Chang’E-2 Microwave Sounder (CELMS) data was employed to study the microwave thermal emission features of [...] Read more.
Mare Moscoviense (148°E, 27°N) is one of the few large maria on the lunar farside, with the thinnest crust and a positive gravity anomaly. In this paper, the Chang’E-2 Microwave Sounder (CELMS) data was employed to study the microwave thermal emission features of mare basalts in Moscoviense Basin. The time angle and linear interpolation method are used to generate the brightness temperature (TB) maps at noon and night, as well as the TB difference (dTB) map. The obtained important results are as follows. (1) A new geologic map is generated with the TB and dTB maps using the maximum likelihood method, which gives a new expression about the basaltic units in Mare Moscoviense compared to the optical results; (2) the substrate temperature of Moscoviense Basin is likely warmer than what we know; (3) unit Ihtm (a Late (?) Imbrian, mid- to high-Ti, high-Fe basalt) is re-understood as two independent volcanic features with their own fissures; (4) the dTB maps firstly indicate that the depth lunar regolith is homogeneous in the highlands surrounding Mare Moscoviense, at least in the microwave domain, and secondly that there exists a special material bringing about the low dTB anomaly in the shallow layer of the east highlands. The results will be of great significance to better understand the basaltic volcanism of the Moon. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Geometric Quality Assessment of Chang’E-2 Global DEM Product
Remote Sens. 2020, 12(3), 526; https://doi.org/10.3390/rs12030526 - 06 Feb 2020
Cited by 1 | Viewed by 756
Abstract
The Chang’E-2 digital elevation model (DEM, named CE2TMap2015), which is the highest resolution DEM product in China, was released with global coverage of the lunar surface. A detailed geometric quality assessment of the product is desirable for wider applications by users. A novel [...] Read more.
The Chang’E-2 digital elevation model (DEM, named CE2TMap2015), which is the highest resolution DEM product in China, was released with global coverage of the lunar surface. A detailed geometric quality assessment of the product is desirable for wider applications by users. A novel procedure for evaluating DEM geometric quality, which investigates both the global geometric uncertainty and local gross errors, is proposed in this paper. First, the DEM was divided into regular blocks and matched with the reference DEM. Then, the characteristics of errors were investigated using the statistical information of the matched tie points. Next, the local outlier factor (LOF) algorithm was performed to locate the gross errors. In our experiment, CE2TMap2015 was evaluated using the proposed method, with SLDEM2015 as the reference DEM. The results show that there were widespread geometric inconsistencies with an area-weighted average of 183.1 m horizontally (with the standard deviation being 101.2 m) and 2.3 m vertically (with the standard deviation being 15.4 m). Gross errors were detected automatically and were excluded in the statistical analysis. The periodic errors were extracted in the frequency domain using a Fourier transform. Our research results provide instructional information for the utilization of CE2TMap2015 by world-wide users. The proposed method can be used in the assessment of other planetary DEMs. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
Simulation Study of Moon-Based InSAR Observation for Solid Earth Tides
Remote Sens. 2020, 12(1), 123; https://doi.org/10.3390/rs12010123 - 01 Jan 2020
Cited by 2 | Viewed by 747
Abstract
The observation of solid earth tides (SET) provides an important basis for understanding the structure of the earth’s interior, and has long been the focus of research in geoscience. However, actually, there still exist some limitations in capturing its global-scale information only with [...] Read more.
The observation of solid earth tides (SET) provides an important basis for understanding the structure of the earth’s interior, and has long been the focus of research in geoscience. However, actually, there still exist some limitations in capturing its global-scale information only with ground stations. Remote sensing technology can realize large-scale deformation monitoring of high point density constantly. However, it is still difficult for the artificial satellite system to meet the requirements of SET monitoring in terms of field of view and temporal resolution now. In this work, the moon is hypothesized as a new platform for SET observation combined with interferometric synthetic aperture radar (InSAR) technology. Based on the tidal model and lunar ephemeris, the spatial and temporal characteristics of the SET from the lunar view were analyzed. Furthermore, the calculations demonstrate that more abundant SET information can be observed in this view. After comparing various observation modes, the single-station with repeat-pass differential InSAR was selected for this simulation. We mainly considered the restriction of observation geometry on moon-based InSAR under three signal bandwidths, thereby providing a reference for the sensor design. The results demonstrate that the moon-based platform offers the potential to become an optimal SET observation method. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessArticle
A Machine Learning Approach to Crater Classification from Topographic Data
Remote Sens. 2019, 11(21), 2594; https://doi.org/10.3390/rs11212594 - 05 Nov 2019
Cited by 1 | Viewed by 1267
Abstract
Craters contain important information on geological history and have been widely used for dating absolute age and reconstructing impact history. The impact process results in a lot of ejected fragments and these fragments may form secondary craters. Studies on distinguishing primary craters from [...] Read more.
Craters contain important information on geological history and have been widely used for dating absolute age and reconstructing impact history. The impact process results in a lot of ejected fragments and these fragments may form secondary craters. Studies on distinguishing primary craters from secondary craters are helpful in improving the accuracy of crater dating. However, previous studies about distinguishing primary craters from secondary craters were either conducted by manual identification or used approaches mainly concerning crater spatial distribution, which are time-consuming or have low accuracy. This paper presents a machine learning approach to distinguish primary craters from secondary craters. First, samples used for training and testing were identified and unified. The whole dataset contained 1032 primary craters and 4041 secondary craters. Then, considering the differences between primary and secondary craters, features mainly related to crater shape, depth, and density were calculated. Finally, a random forest classifier was trained and tested. This approach showed a favorable performance. The accuracy and F1-score for fivefold cross-validation were 0.939 and 0.839, respectively. The proposed machine learning approach enables an automated method of distinguishing primary craters from secondary craters, which results in better performance. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessTechnical Note
Application of Denoising CNN for Noise Suppression and Weak Signal Extraction of Lunar Penetrating Radar Data
Remote Sens. 2021, 13(4), 779; https://doi.org/10.3390/rs13040779 - 20 Feb 2021
Cited by 1 | Viewed by 467
Abstract
As one of the main payloads mounted on the Yutu-2 rover of Chang’E-4 probe, lunar penetrating radar (LPR) aims to map the subsurface structure in the Von Kármán crater. The field LPR data are generally masked by clutters and noises of large quantities. [...] Read more.
As one of the main payloads mounted on the Yutu-2 rover of Chang’E-4 probe, lunar penetrating radar (LPR) aims to map the subsurface structure in the Von Kármán crater. The field LPR data are generally masked by clutters and noises of large quantities. To solve the noise interference, dozens of filtering methods have been applied to LPR data. However, these methods have their limitations, so noise suppression is still a tough issue worth studying. In this article, the denoising convolutional neural network (CNN) framework is applied to the noise suppression and weak signal extraction of 500 MHz LPR data. The results verify that the low-frequency clutters embedded in the LPR data mainly came from the instrument system of the Yutu rover. Besides, compared with the classic band-pass filter and the mean filter, the CNN filter has better performance when dealing with noise interference and weak signal extraction; compared with Kirchhoff migration, it can provide original high-quality radargram with diffraction information. Based on the high-quality radargram provided by the CNN filter, the subsurface sandwich structure is revealed and the weak signals from three sub-layers within the paleo-regolith are extracted. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessTechnical Note
Rock Location and Property Analysis of Lunar Regolith at Chang’E-4 Landing Site Based on Local Correlation and Semblance Analysis
Remote Sens. 2021, 13(1), 48; https://doi.org/10.3390/rs13010048 - 24 Dec 2020
Cited by 2 | Viewed by 574
Abstract
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 [...] Read more.
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. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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Open AccessTechnical Note
Analyzing the Magnesium (Mg) Number of Olivine on the Lunar Surface and Its Geological Significance
Remote Sens. 2019, 11(13), 1544; https://doi.org/10.3390/rs11131544 - 28 Jun 2019
Viewed by 1077
Abstract
Olivine formation is directly related to Mg/Fe content. It is also significant in estimating the geological evolution of the moon. In this study, an estimation model of relative Mg number (Fo#) for lunar olivine was presented through multiple linear regression statistics. Sinus Iridum, [...] Read more.
Olivine formation is directly related to Mg/Fe content. It is also significant in estimating the geological evolution of the moon. In this study, an estimation model of relative Mg number (Fo#) for lunar olivine was presented through multiple linear regression statistics. Sinus Iridum, the Copernicus Crater, and the pyroclastic deposit in the volcanic vents in the southeast of Orientale Basin were selected as the study areas. Olivine distribution was surveyed, and the relative Fo# calculation of olivine was implemented based on Moon Mineralogy Mapper (M3) data. Results demonstrated that olivine in the crater wall of Sinus Iridum and the Copernicus Crater had relatively high Fo#, which reflected the primitive melt. However, the difference in olivine spectral features between Sinus Iridum and the Copernicus Crater indicated different crystallization modes. The olivine in the pyroclastic deposit in the volcanic vents in the southwest of Orientale Basin also presented high Fo#, which indicated that the olivine was formed via rapid cooling crystallization and was accompanied by volcanic glass substances. As a result, the olivine relative Fo# calculated from the estimation model exhibited an important constraint implication for explanation of its causes. Full article
(This article belongs to the Special Issue Lunar Remote Sensing and Applications)
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