Leading national space exploration agencies and private enterprises are actively engaged in lunar exploration initiatives to accomplish manned lunar landings and establish permanent lunar bases in the forthcoming year...Leading national space exploration agencies and private enterprises are actively engaged in lunar exploration initiatives to accomplish manned lunar landings and establish permanent lunar bases in the forthcoming years.With limited access to lunar surface materials on Earth,lunar regolith simulants are crucial for lunar exploration research.The Chang’e-5(CE-5)samples have been characterized by state-of-the-art laboratory equipment,providing a unique opportunity to develop a high-quality lunar regolith simulant.We have prepared a high-fidelity PolyU-1 simulant by pulverizing,desiccating,sieving,and blending natural mineral materials on Earth based on key physical,mineral,and chemical characteristics of CE-5 samples.The results showed that the simulant has a high degree of consistency with the CE-5 samples in terms of the particle morphology,mineral and chemical composition.Direct shear tests were conducted on the simulant,and the measured internal friction angle and cohesion values can serve as references for determining the mechanical properties of CE-5 lunar regolith.The PolyU-1 simulant can contribute to experimental studies involving lunar regolith,including the assessment of interaction between rovers and lunar regolith,as well as the development of in-situ resource utilization(ISRU)technologies.展开更多
Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in sit...Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in situ.However,space metallurgy on the Moon is challenging because the lunar surface has experienced space weathering due to the lack of atmosphere and magnetic field,making the mi-crostructure of lunar soil differ from that of minerals on the Earth.In this study,scanning electron microscopy and transmission electron microscopy analyses were performed on Chang’e-5 powder lunar soil samples.The microstructural characteristics of the lunar soil may drastically change its metallurgical performance.The main special structure of lunar soil minerals include the nanophase iron formed by the impact of micrometeorites,the amorphous layer caused by solar wind injection,and radiation tracks modified by high-energy particle rays inside mineral crystals.The nanophase iron presents a wide distribution,which may have a great impact on the electromagnetic prop-erties of lunar soil.Hydrogen ions injected by solar wind may promote the hydrogen reduction process.The widely distributed amorph-ous layer and impact glass can promote the melting and diffusion process of lunar soil.Therefore,although high-energy events on the lun-ar surface transform the lunar soil,they also increase the chemical activity of the lunar soil.This is a property that earth samples and tradi-tional simulated lunar soil lack.The application of space metallurgy requires comprehensive consideration of the unique physical and chemical properties of lunar soil.展开更多
Through microscopic analyses(e.g.,organic macerals,thin section observation,scanning electron microscope(SEM)imaging of fresh bedding planes via argon ion milling,and energy spectrum tests)combined with Rock-Eval anal...Through microscopic analyses(e.g.,organic macerals,thin section observation,scanning electron microscope(SEM)imaging of fresh bedding planes via argon ion milling,and energy spectrum tests)combined with Rock-Eval analyses,this study systematically investigated the organic matter and pyrites in the continental shales in the 3^(rd)submember of the Chang 7 Member(Chang 7^(3)submember)in the Yanchang Formation,Ordos Basin and determined their types and the formation and evolutionary characteristics.The results are as follows.The organic matter of the continental shales in the Chang 7^(3)submember is dominated by amorphous bituminites and migrabitumens,which have come into being since the early diagenetic stage and middle diagenetic stage A,respectively.The formation and transformation of organic matter is a prerequisite for the formation of pyrites.The Ordos Basin was a continental freshwater lacustrine basin and lacked sulphates in waters during the deposition of the Chang 7 Member.Therefore,the syndiagenetic stage did not witness the formation of large quantities of pyrites.Since the basin entered early diagenetic stage A,large quantities of sulfur ions were released as the primary organic matter got converted into bituminites and,accordingly,pyrites started to form.However,this stage featured poorer fluid and spatial conditions compared with the syndepositional stage due to withdraw of water,the partial formation of bituminites,and a certain degree of compaction.As a result,large quantities of pyrrhotite failed to transition into typical spherical framboidal pyrites but grew into euhedral monocrystal aggregates.In addition,pyrites are still visible in the migrabitumens in both microfractures and inorganic pores of mudstones and shales,indicating that the pyrite formation period can extend until the middle diagenetic stage A.展开更多
Lunar Penetrating Radar （LPR） is one of the important scientific instru- ments onboard the Chang＇e-3 spacecraft. Its scientific goals are the mapping of lunar regolith and detection of subsurface geologic structure...Lunar Penetrating Radar （LPR） is one of the important scientific instru- ments onboard the Chang＇e-3 spacecraft. Its scientific goals are the mapping of lunar regolith and detection of subsurface geologic structures. This paper describes the goals of the mission, as well as the basic principles, design, composition and achievements of the LPR. Finally, experiments on a glacier and the lunar surface are analyzed.展开更多
The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion effi...The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion efficiency and roof/floor sealing conditions of the Chang 7_(3) shale,and evaluates the major enrichment type of shale oil in this interval.The average organic matter transformation ratio of the Chang 7_(3) shale is about 45%;in other words,more than 50%of the organic matters have not transformed to hydrocarbons,and the lower the maturity,the greater the proportion of untransformed organic matters.The cumulative hydrocarbon expulsion efficiency of the transformed hydrocarbon is 27.5% on average,and the total proportion of untransformed organic matters plus retained hydrocarbons is greater than 70%.The relative hydrocarbon expulsion efficiency of the Chang 7_(3) shale is 60%on average,that is,about 40% of hydrocarbons retain in the shale.The Chang 7_(3) shale corresponds to Chang 7_(1+2) and Chang 8 sandstones as the roof and floor,respectively,and is further overlaid by Chang 6 shale,where extensive low porosity and low permeability–tight oil reservoirs have formed in the parts with relatively good porosity and permeability.Moreover,the Chang 7_(3) shale is tested to be in a negative pressure system(the pressure coefficient of 0.80–0.85).Therefore,the roof/floor sealing conditions of the Chang 7_(3) shale are poor.The retained hydrocarbons appear mostly in absorbed status,with low mobility.It is concluded that the medium–high mature shale oil is not the major enrichment type of shale oil in the Chang 7_(3) shale,but there may be enrichment opportunity for shale oil with good mobility in the areas where the sealing conditions are good without faults and fractures and oil reservoirs are formed off Chang 7_(1+2),Chang 6 and Chang 8.Furthermore,low–medium mature shale oil is believed to have great potential and is the major enrichment type of shale oil in the Chang 7_(3) shale.It is recommended to prepare relevant in-situ conversion technologies by pilot test and figure out the resource availability and distribution.展开更多
The process of development and calibration for the first Moon-based ex- treme ultraviolet （EUV） camera to observe Earth＇s plasmasphere is introduced and the design, test and calibration results are presented. The E...The process of development and calibration for the first Moon-based ex- treme ultraviolet （EUV） camera to observe Earth＇s plasmasphere is introduced and the design, test and calibration results are presented. The EUV camera is composed of a multilayer film mirror, a thin film filter, a photon-counting imaging detector, a mech- anism that can adjust the direction in two dimensions, a protective cover, an electronic unit and a thermal control unit. The center wavelength of the EUV camera is 30.2 nm with a bandwidth of 4.6nm. The field of view is 14.7° with an angular resolution of 0.08°, and the sensitivity of the camera is 0.11 count s-1 Rayleigh-1. The geomet- ric calibration, the absolute photometric calibration and the relative photometric cal- ibration are carried out under different temperatures before launch to obtain a matrix that can correct geometric distortion and a matrix for relative photometric correction, which are used for in-orbit correction of the images to ensure their accuracy.展开更多
The Chang＇e-3 Visible and Near-infrared Imaging Spectrometer （VNIS） is one of the four payloads on the Yutu rover. After traversing the landing site during the first two lunar days, four different areas are detecte...The Chang＇e-3 Visible and Near-infrared Imaging Spectrometer （VNIS） is one of the four payloads on the Yutu rover. After traversing the landing site during the first two lunar days, four different areas are detected, and Level 2A and 2B ra- diance data have been released to the scientific community. The released data have been processed by dark current subtraction, correction for the effect of temperature, radiometric calibration and geometric calibration. We emphasize approaches for re- flectance analysis and mineral identification for in-situ analysis with VNIS. Then the preliminary spectral and mineralogical results from the landing site are derived. After comparing spectral data from VNIS with data collected by the Ma instrument and samples of mare that were returned from the Apollo program, all the reflectance data have been found to have similar absorption features near 1000 nm except lunar sample 71061. In addition, there is also a weak absorption feature between 1750-2400nm on VNIS, but the slopes of VNIS and Ma reflectance at longer wavelengths are lower than data taken from samples of lunar mare. Spectral parameters such as Band Centers and Integrated Band Depth Ratios are used to analyze mineralogical features. The results show that detection points E and N205 are mixtures of high-Ca pyroxene and olivine, and the composition of olivineat point N205 is higher than that at point E, but the compositions of detection points S3 and N203 are mainly olivine-rich. Since there are no obvious absorption features near 1250 nm, plagioclase is not directly identified at the landing site.展开更多
The Chang＇e-3 （CE-3） lander and rover mission to the Moon was an in- termediate step in China＇s lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number o...The Chang＇e-3 （CE-3） lander and rover mission to the Moon was an in- termediate step in China＇s lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras （Landing Camera and Terrain Camera） for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth＇s plasmasphere, and a first-ever Moon-based ultravi- olet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle-induced X-ray Spectrometer, and pioneering measurements of the lunar sub- surface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing pro- cedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions.展开更多
The plasmapause locations determined from the Chang'e-3(CE-3) Extreme Ultraviolet Camera(EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program(DMSP) Special Sensor Ul...The plasmapause locations determined from the Chang'e-3(CE-3) Extreme Ultraviolet Camera(EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program(DMSP) Special Sensor Ultraviolet Spectrographic Imager(SSUSI) images are used to investigate the plasmaspheric evolutions during substorms. The most important finding is a nightside pointing plasmaspheric plume observed at 23:05 UT on 21 April 2014 under quiet solar wind and geomagnetic conditions, which drifted from the dusk sector. High correlations between the plasmapause evolutions and the auroral signatures exist during substorms. After substorm onset, the plasmapause erosion and the equatorward expansion of the auroral oval occur almost simultaneously in both MLT and UT, and then both the erosion and the expansion propagate westward and eastward. It is suggested that the plasmaspheric erosion and its MLT propagations are induced by the enhanced earthward plasma convection during substorm period, and the substorm dipolarization causes pitch-angle scattering of plasma sheet electrons and the resulting precipitation excites aurora emissions at the same time.展开更多
Chang'E-3 probe incorporates four landing gears to assure the soft-landing,which are stowed while launching and deployed after separated from rocket. Deployment reliability is quite crucial for this mission. The d...Chang'E-3 probe incorporates four landing gears to assure the soft-landing,which are stowed while launching and deployed after separated from rocket. Deployment reliability is quite crucial for this mission. The deployment reliability test( DRT) method and assessment method were developed in this paper. Then DRT was conducted and the deployment reliability estimate of Chang'E-3probe was used to verify the proposed methods.展开更多
This study proposes a detailed concept of how landscape changes can be transferred and communicated in a 3D environment using the storytelling approach. In 2018, Mocnik and Fairbairn argued that maps are good for repr...This study proposes a detailed concept of how landscape changes can be transferred and communicated in a 3D environment using the storytelling approach. In 2018, Mocnik and Fairbairn argued that maps are good for representing a geographic space but texts have a better benefit than maps for telling a story [1]. A framework is presented on how a landscape change can be retrieved out of textual descriptions. A prototype of a 3D model with a projection on top of it was developed. The case study tells the story of the landscape change in the city of Pristina. The key element of the visualization is a timeline. Several media like cadastral maps, orthophotos, texts, graphics, and background sound are used and combined in an animated light show and the visualization was evaluated within a user study.展开更多
Nomenclatures for lunar features always accompany the progresses of human lunar exploration,which has an important dual meaning in culture and science. The naming of lunar features not only can commemorate the outstan...Nomenclatures for lunar features always accompany the progresses of human lunar exploration,which has an important dual meaning in culture and science. The naming of lunar features not only can commemorate the outstanding contributions of academics,masters in various fields, and popularize the traditional cultures of ethnic groups all over the world, but also have a critical function of providing accurate indicative information on features with special morphology, origin, nature and scientific value. However, nomenclature for features at the Chang'e-3 landing site, which has a more arbitrary form without many constrains posed by a uniformed system, is unlike the features for other morphological units.This paper originated from the actual needs for the description of scientific exploration activities, interpretation of scientific research and dissemination of scientific results. Some prominent morphological units with great scientific importance and identification purpose were chosen from the images taken by the terrain camera, panorama cameras and landing camera onboard the Chang'e lander and Yutu rover. A nomenclature system was established under the three enclosures, four quadrants and twenty-eight lunar lodges' system of the Chinese ancient sky division method. Finally, a standard feature names set waspublished after some necessary approval procedures by the International Astronomical Union.展开更多
An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MO...An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MOF difficulties in computing solutions to problems in which surface tension forces are crucial for understanding salient flow mechanisms.The Continuous MOF(CMOF)method is motivated in this article.The CMOF reconstruction method inherently removes the"checkerboard instability"that persists when using the MOF method on surface tension driven multiphase(multimaterial)flows.The CMOF reconstruction algorithm is accelerated by coupling the CMOF method to the level set method and coupling the CMOF method to a decision tree machine learning(ML)algorithm.Multiphase flow examples are shown in the two-dimensional(2D),three-dimensional(3D)axisymmetric"RZ",and 3D coordinate systems.Examples include two material and three material multiphase flows:bubble formation,the impingement of a liquid jet on a gas bubble in a cryogenic fuel tank,freezing,and liquid lens dynamics.展开更多
基金supported by the PolyU RCDSE projects(Nos.P0049221 and P0041304)We would like to express our sincere gratitude to Prof.Feng Li and Dr.Siqi Zhou from Beihang University for providing us with the BH-1 simulant,which served as the crucial reference for the PolyU-1 simulant.We would like to thank the support from the National Natural Science Foundation of China(No.42241103)the Key Research Program of the Institute of Geology and Geophysics,Chinese Academy of Sciences(No.IGGCAS-202101)。
文摘Leading national space exploration agencies and private enterprises are actively engaged in lunar exploration initiatives to accomplish manned lunar landings and establish permanent lunar bases in the forthcoming years.With limited access to lunar surface materials on Earth,lunar regolith simulants are crucial for lunar exploration research.The Chang’e-5(CE-5)samples have been characterized by state-of-the-art laboratory equipment,providing a unique opportunity to develop a high-quality lunar regolith simulant.We have prepared a high-fidelity PolyU-1 simulant by pulverizing,desiccating,sieving,and blending natural mineral materials on Earth based on key physical,mineral,and chemical characteristics of CE-5 samples.The results showed that the simulant has a high degree of consistency with the CE-5 samples in terms of the particle morphology,mineral and chemical composition.Direct shear tests were conducted on the simulant,and the measured internal friction angle and cohesion values can serve as references for determining the mechanical properties of CE-5 lunar regolith.The PolyU-1 simulant can contribute to experimental studies involving lunar regolith,including the assessment of interaction between rovers and lunar regolith,as well as the development of in-situ resource utilization(ISRU)technologies.
基金CNSA for providing access to the lunar sample CE5C0200YJFM00302funding support from the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB 41000000)+5 种基金the National Natural Science Foundation of China (Nos. 42273042 and 41931077)the Youth Innovation Promotion Association Chinese Academy of Sciences (No. 2020395)Key Research Program of Frontier Sciences, Chinese Academy of Sciences (Nos. ZDBS-SSW-JSC00710 and QYZDY-SSW-DQC028)the Young and Middleaged Academic Technology Leader Reserve Talent Project of Yunnan Province (No. 2018HB009)the Science Fund for Outstanding Youth of Yunnan Province (No. 202101 AV070007)the "From 0 to 1" Original Exploration Cultivation Project, Institute of Geochemistry, Chinese Academy of Sciences (No. DHSZZ2023-3)
文摘Space metallurgy is an interdisciplinary field that combines planetary space science and metallurgical engineering.It involves systematic and theoretical engineering technology for utilizing planetary resources in situ.However,space metallurgy on the Moon is challenging because the lunar surface has experienced space weathering due to the lack of atmosphere and magnetic field,making the mi-crostructure of lunar soil differ from that of minerals on the Earth.In this study,scanning electron microscopy and transmission electron microscopy analyses were performed on Chang’e-5 powder lunar soil samples.The microstructural characteristics of the lunar soil may drastically change its metallurgical performance.The main special structure of lunar soil minerals include the nanophase iron formed by the impact of micrometeorites,the amorphous layer caused by solar wind injection,and radiation tracks modified by high-energy particle rays inside mineral crystals.The nanophase iron presents a wide distribution,which may have a great impact on the electromagnetic prop-erties of lunar soil.Hydrogen ions injected by solar wind may promote the hydrogen reduction process.The widely distributed amorph-ous layer and impact glass can promote the melting and diffusion process of lunar soil.Therefore,although high-energy events on the lun-ar surface transform the lunar soil,they also increase the chemical activity of the lunar soil.This is a property that earth samples and tradi-tional simulated lunar soil lack.The application of space metallurgy requires comprehensive consideration of the unique physical and chemical properties of lunar soil.
基金funded by the subproject of the National Science and Technology Major Project(No.2017ZX05036004).
文摘Through microscopic analyses(e.g.,organic macerals,thin section observation,scanning electron microscope(SEM)imaging of fresh bedding planes via argon ion milling,and energy spectrum tests)combined with Rock-Eval analyses,this study systematically investigated the organic matter and pyrites in the continental shales in the 3^(rd)submember of the Chang 7 Member(Chang 7^(3)submember)in the Yanchang Formation,Ordos Basin and determined their types and the formation and evolutionary characteristics.The results are as follows.The organic matter of the continental shales in the Chang 7^(3)submember is dominated by amorphous bituminites and migrabitumens,which have come into being since the early diagenetic stage and middle diagenetic stage A,respectively.The formation and transformation of organic matter is a prerequisite for the formation of pyrites.The Ordos Basin was a continental freshwater lacustrine basin and lacked sulphates in waters during the deposition of the Chang 7 Member.Therefore,the syndiagenetic stage did not witness the formation of large quantities of pyrites.Since the basin entered early diagenetic stage A,large quantities of sulfur ions were released as the primary organic matter got converted into bituminites and,accordingly,pyrites started to form.However,this stage featured poorer fluid and spatial conditions compared with the syndepositional stage due to withdraw of water,the partial formation of bituminites,and a certain degree of compaction.As a result,large quantities of pyrrhotite failed to transition into typical spherical framboidal pyrites but grew into euhedral monocrystal aggregates.In addition,pyrites are still visible in the migrabitumens in both microfractures and inorganic pores of mudstones and shales,indicating that the pyrite formation period can extend until the middle diagenetic stage A.
基金funded by the second phase of the Chinese Lunar Exploration Program
文摘Lunar Penetrating Radar （LPR） is one of the important scientific instru- ments onboard the Chang＇e-3 spacecraft. Its scientific goals are the mapping of lunar regolith and detection of subsurface geologic structures. This paper describes the goals of the mission, as well as the basic principles, design, composition and achievements of the LPR. Finally, experiments on a glacier and the lunar surface are analyzed.
基金Supported by the National Natural Science Foundation of China(U22B6004).
文摘The major enrichment type of shale oil in the Chang 7_(3) shale of Upper Triassic Yanchang Formation in the Ordos Basin is unknown.This paper analyzes the organic matter transformation ratio,hydrocarbon expulsion efficiency and roof/floor sealing conditions of the Chang 7_(3) shale,and evaluates the major enrichment type of shale oil in this interval.The average organic matter transformation ratio of the Chang 7_(3) shale is about 45%;in other words,more than 50%of the organic matters have not transformed to hydrocarbons,and the lower the maturity,the greater the proportion of untransformed organic matters.The cumulative hydrocarbon expulsion efficiency of the transformed hydrocarbon is 27.5% on average,and the total proportion of untransformed organic matters plus retained hydrocarbons is greater than 70%.The relative hydrocarbon expulsion efficiency of the Chang 7_(3) shale is 60%on average,that is,about 40% of hydrocarbons retain in the shale.The Chang 7_(3) shale corresponds to Chang 7_(1+2) and Chang 8 sandstones as the roof and floor,respectively,and is further overlaid by Chang 6 shale,where extensive low porosity and low permeability–tight oil reservoirs have formed in the parts with relatively good porosity and permeability.Moreover,the Chang 7_(3) shale is tested to be in a negative pressure system(the pressure coefficient of 0.80–0.85).Therefore,the roof/floor sealing conditions of the Chang 7_(3) shale are poor.The retained hydrocarbons appear mostly in absorbed status,with low mobility.It is concluded that the medium–high mature shale oil is not the major enrichment type of shale oil in the Chang 7_(3) shale,but there may be enrichment opportunity for shale oil with good mobility in the areas where the sealing conditions are good without faults and fractures and oil reservoirs are formed off Chang 7_(1+2),Chang 6 and Chang 8.Furthermore,low–medium mature shale oil is believed to have great potential and is the major enrichment type of shale oil in the Chang 7_(3) shale.It is recommended to prepare relevant in-situ conversion technologies by pilot test and figure out the resource availability and distribution.
文摘The process of development and calibration for the first Moon-based ex- treme ultraviolet （EUV） camera to observe Earth＇s plasmasphere is introduced and the design, test and calibration results are presented. The EUV camera is composed of a multilayer film mirror, a thin film filter, a photon-counting imaging detector, a mech- anism that can adjust the direction in two dimensions, a protective cover, an electronic unit and a thermal control unit. The center wavelength of the EUV camera is 30.2 nm with a bandwidth of 4.6nm. The field of view is 14.7° with an angular resolution of 0.08°, and the sensitivity of the camera is 0.11 count s-1 Rayleigh-1. The geomet- ric calibration, the absolute photometric calibration and the relative photometric cal- ibration are carried out under different temperatures before launch to obtain a matrix that can correct geometric distortion and a matrix for relative photometric correction, which are used for in-orbit correction of the images to ensure their accuracy.
基金Supported by the National Natural Science Foundation of China
文摘The Chang＇e-3 Visible and Near-infrared Imaging Spectrometer （VNIS） is one of the four payloads on the Yutu rover. After traversing the landing site during the first two lunar days, four different areas are detected, and Level 2A and 2B ra- diance data have been released to the scientific community. The released data have been processed by dark current subtraction, correction for the effect of temperature, radiometric calibration and geometric calibration. We emphasize approaches for re- flectance analysis and mineral identification for in-situ analysis with VNIS. Then the preliminary spectral and mineralogical results from the landing site are derived. After comparing spectral data from VNIS with data collected by the Ma instrument and samples of mare that were returned from the Apollo program, all the reflectance data have been found to have similar absorption features near 1000 nm except lunar sample 71061. In addition, there is also a weak absorption feature between 1750-2400nm on VNIS, but the slopes of VNIS and Ma reflectance at longer wavelengths are lower than data taken from samples of lunar mare. Spectral parameters such as Band Centers and Integrated Band Depth Ratios are used to analyze mineralogical features. The results show that detection points E and N205 are mixtures of high-Ca pyroxene and olivine, and the composition of olivineat point N205 is higher than that at point E, but the compositions of detection points S3 and N203 are mainly olivine-rich. Since there are no obvious absorption features near 1250 nm, plagioclase is not directly identified at the landing site.
文摘The Chang＇e-3 （CE-3） lander and rover mission to the Moon was an in- termediate step in China＇s lunar exploration program, which will be followed by a sample return mission. The lander was equipped with a number of remote-sensing instruments including a pair of cameras （Landing Camera and Terrain Camera） for recording the landing process and surveying terrain, an extreme ultraviolet camera for monitoring activities in the Earth＇s plasmasphere, and a first-ever Moon-based ultravi- olet telescope for astronomical observations. The Yutu rover successfully carried out close-up observations with the Panoramic Camera, mineralogical investigations with the VIS-NIR Imaging Spectrometer, study of elemental abundances with the Active Particle-induced X-ray Spectrometer, and pioneering measurements of the lunar sub- surface with Lunar Penetrating Radar. This special issue provides a collection of key information on the instrumental designs, calibration methods and data processing pro- cedures used by these experiments with a perspective of facilitating further analyses of scientific data from CE-3 in preparation for future missions.
基金supported by National Natural Science Foundation of China (41674155 and 41274147)Youth Innovation Promotion Association of Chinese Academy of Sciences (No.2017258)Key Research Project of Chinese Academy of Sciences:Application Research on the Scientific Data from Chang’E-3 Mission (KGZD-EW-603)
文摘The plasmapause locations determined from the Chang'e-3(CE-3) Extreme Ultraviolet Camera(EUVC) images and the auroral boundaries determined from the Defense Meteorological Satellite Program(DMSP) Special Sensor Ultraviolet Spectrographic Imager(SSUSI) images are used to investigate the plasmaspheric evolutions during substorms. The most important finding is a nightside pointing plasmaspheric plume observed at 23:05 UT on 21 April 2014 under quiet solar wind and geomagnetic conditions, which drifted from the dusk sector. High correlations between the plasmapause evolutions and the auroral signatures exist during substorms. After substorm onset, the plasmapause erosion and the equatorward expansion of the auroral oval occur almost simultaneously in both MLT and UT, and then both the erosion and the expansion propagate westward and eastward. It is suggested that the plasmaspheric erosion and its MLT propagations are induced by the enhanced earthward plasma convection during substorm period, and the substorm dipolarization causes pitch-angle scattering of plasma sheet electrons and the resulting precipitation excites aurora emissions at the same time.
基金National Science and Technology Major Project,China
文摘Chang'E-3 probe incorporates four landing gears to assure the soft-landing,which are stowed while launching and deployed after separated from rocket. Deployment reliability is quite crucial for this mission. The deployment reliability test( DRT) method and assessment method were developed in this paper. Then DRT was conducted and the deployment reliability estimate of Chang'E-3probe was used to verify the proposed methods.
文摘This study proposes a detailed concept of how landscape changes can be transferred and communicated in a 3D environment using the storytelling approach. In 2018, Mocnik and Fairbairn argued that maps are good for representing a geographic space but texts have a better benefit than maps for telling a story [1]. A framework is presented on how a landscape change can be retrieved out of textual descriptions. A prototype of a 3D model with a projection on top of it was developed. The case study tells the story of the landscape change in the city of Pristina. The key element of the visualization is a timeline. Several media like cadastral maps, orthophotos, texts, graphics, and background sound are used and combined in an animated light show and the visualization was evaluated within a user study.
基金provided by National Major Projects-GRAS Construction of China Lunar Exploration Project
文摘Nomenclatures for lunar features always accompany the progresses of human lunar exploration,which has an important dual meaning in culture and science. The naming of lunar features not only can commemorate the outstanding contributions of academics,masters in various fields, and popularize the traditional cultures of ethnic groups all over the world, but also have a critical function of providing accurate indicative information on features with special morphology, origin, nature and scientific value. However, nomenclature for features at the Chang'e-3 landing site, which has a more arbitrary form without many constrains posed by a uniformed system, is unlike the features for other morphological units.This paper originated from the actual needs for the description of scientific exploration activities, interpretation of scientific research and dissemination of scientific results. Some prominent morphological units with great scientific importance and identification purpose were chosen from the images taken by the terrain camera, panorama cameras and landing camera onboard the Chang'e lander and Yutu rover. A nomenclature system was established under the three enclosures, four quadrants and twenty-eight lunar lodges' system of the Chinese ancient sky division method. Finally, a standard feature names set waspublished after some necessary approval procedures by the International Astronomical Union.
基金supported by the National Aeronautics and Space Administration under grant number 80NSSC20K0352.
文摘An improved algorithm for computing multiphase flows is presented in which the multimaterial Moment-of-Fluid(MOF)algorithm for multiphase flows,initially described by Li et al.(2015),is enhanced addressing existing MOF difficulties in computing solutions to problems in which surface tension forces are crucial for understanding salient flow mechanisms.The Continuous MOF(CMOF)method is motivated in this article.The CMOF reconstruction method inherently removes the"checkerboard instability"that persists when using the MOF method on surface tension driven multiphase(multimaterial)flows.The CMOF reconstruction algorithm is accelerated by coupling the CMOF method to the level set method and coupling the CMOF method to a decision tree machine learning(ML)algorithm.Multiphase flow examples are shown in the two-dimensional(2D),three-dimensional(3D)axisymmetric"RZ",and 3D coordinate systems.Examples include two material and three material multiphase flows:bubble formation,the impingement of a liquid jet on a gas bubble in a cryogenic fuel tank,freezing,and liquid lens dynamics.
