Chang’E-4(CE-4)successfully landed on the floor of the Von Kármán crater within the South Pole-Aitken basin(SPA).One of its scientific objectives is to determine the subsurface structure and the thickness o...Chang’E-4(CE-4)successfully landed on the floor of the Von Kármán crater within the South Pole-Aitken basin(SPA).One of its scientific objectives is to determine the subsurface structure and the thickness of lunar regolith at the landing site and along the traverse route of the Yutu-2 rover.Using orbital data,we employed small craters(diameters<1 km)on the floor of the Von Kármán crater as probes to investigate the subsurface structure and stratigraphy of the CE-4 landing site.In this study,40 dark-haloed craters that penetrate through the surface Finsen ejecta and excavate underlying mare deposits were identified,and 77 bright ray craters that expose only the underlying fresh materials but do not penetrate through the surface Finsen ejecta were found.The excavation depths of these craters and their distances from the Finsen crater center were calculated,and the thickness distribution of Finsen ejecta on the Von Kármán floor was systematically investigated.The boundary between Finsen ejecta and underlying mare basalt at the CE-4 landing site is constrained to a depth of 18 m.We have proposed the stratigraphy for the CE-4 site and interpreted the origins of different layers and the geological history of the Von Kármán crater.These results provide valuable geological background for interpreting data from the Lunar Penetrating Radar(LPR)and Visible and Near-infrared Imaging Spectrometer(VNIS)on the Yutu-2 rover.The CE-4 landing site could provide a reference point for crater ejecta distribution and mixing with local materials,to test and improve ejecta thickness models according to the in situ measurements of the CE-4 LPR.展开更多
On 3 January 2019,the Chang’E-4 probe successfully landed in the Von Kármán crater in the South Pole-Aitken Basin on the far side of the Moon.On 4 January,the Yutu-2 rover was successfully separated from th...On 3 January 2019,the Chang’E-4 probe successfully landed in the Von Kármán crater in the South Pole-Aitken Basin on the far side of the Moon.On 4 January,the Yutu-2 rover was successfully separated from the lander and the scientific payloads were powered on to conduct scientific exploration.It was the first time that manmade probe achieved soft landing and roving on the far side of the Moon.Based on the data obtained by scientific payloads on the Chang’E-4,the research team obtained geological information such as landing area topography,structure and composition;demonstrated the existence of deep materials—mainly olivine and low-calcium pyroxene in the South Pole-Aitken Basin;achieved high-precision imaging of the layered structure of lunar subsurface in the roving area;discovered carbonaceous spheroidal meteorite residues and impact glass;preliminarily revealed the geological evolutionary history of the South Pole-Aitken Basin;for the first time,obtained information of the radiation dose of energetic particles at the lunar surface and the structure of the lunar neutral atomic energy spectrum;discovered the lunar mini-magnetosphere and contributed new knowledge of the radiation hazards at the lunar surface.This article summarizes the latest scientific achievement from the Chang’E-4 mission over the past three years.展开更多
China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of th...China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of the Moon in human history.Chang'E-5 was launched in December 2020,bringing back 1731 g of lunar soil samples.Through the detailed analysis of the samples,the scientists understand the history of late lunar volcanism,specifically extending lunar volcanism by about 800 million to 1 billion years,and proposed possible mechanisms.In addition,there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon.China's first Mars exploration mission Tianwen-1 was successfully launched in July 2021.Through the study of scientific data,a number of important scientific achievements have been made in the topography,water environment and shallow surface structure of Mars.This paper introduces the main scientific achievements of Chang'E-4,Chang'E-5 and Tianwen-1 in the past two years,excluding technical and engineering contents.Due to the large number of articles involved,this paper only introduces part of the results.展开更多
The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurfac...The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurface structures within a depth of approximately 50 m.However,it was still difficult to identify finer layers from the cluttered reflections and scattering waves.We applied deconvolution to improve the vertical resolution of the radar profile by extending the limited bandwidth associated with the emissive radar pulse.To overcome the challenges arising from the mixed-phase wavelets and the problematic amplification of noise,we performed predictive deconvolution to remove the minimum-phase components from the Chang’E-4 dataset,followed by a comprehensive phase rotation to rectify phase anomalies in the radar image.Subsequently,we implemented irreversible migration filtering to mitigate the noise and diminutive clutter echoes amplified by deconvolution.The processed data showed evident enhancement of the vertical resolution with a widened bandwidth in the frequency domain and better signal clarity in the time domain,providing us with more undisputed details of subsurface structures near the Chang’E-4 landing site.展开更多
China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard...China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard the lander and the rover,the researchers obtained the related information such as the geologic and tectonic setting of the landing area,compositional characteristics of the landing surface materials,dielectric permittivity and density of the lunar soil.The experiments confirmed the existence of materials dominated by olivine and low-calcium pyroxene in the SPA basin on the lunar far side,which preliminary revealed the geological evolution history of the SPA basin and even that of the early time lunar crust,as well as the tectonic setting and formation mechanism of the materials in the lunar interior.The researchers also investigated the particle radiation,Linear Energy Transaction(LET)spectrum,and so forth on the lunar surface.The low-frequency radio observations were carried out on the lunar far side for the first time as well.This article summarizes the latest scientific results in the past years,focusing on the Chang’E-4 mission.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos. 41490633 and 41590851)the open fund of the State Key Laboratory of Lunar and Planetary Sciences (Macao University of Science and Technology) (Macao FDCT Grant No. 119/2017/A3)+6 种基金the open fund of the Key Laboratory of Lunar and Deep Space Exploration, Chinese Academy of Sciencessupported by the National Natural Science Foundation of China (U1931211, 41972322 and 11941001)the Natural Science Foundation of Shandong Province (ZR2019MD008)Qilu (Tang) Young Scholars Program of Shandong University, Weihai (2015WHWLJH14)supported by the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT, 2017TD-26)the Focus on Research and Development Plan in Shandong Province (2018GGX101028)the Shandong Provincial Natural Science Foundation (ZR2019MD015)
文摘Chang’E-4(CE-4)successfully landed on the floor of the Von Kármán crater within the South Pole-Aitken basin(SPA).One of its scientific objectives is to determine the subsurface structure and the thickness of lunar regolith at the landing site and along the traverse route of the Yutu-2 rover.Using orbital data,we employed small craters(diameters<1 km)on the floor of the Von Kármán crater as probes to investigate the subsurface structure and stratigraphy of the CE-4 landing site.In this study,40 dark-haloed craters that penetrate through the surface Finsen ejecta and excavate underlying mare deposits were identified,and 77 bright ray craters that expose only the underlying fresh materials but do not penetrate through the surface Finsen ejecta were found.The excavation depths of these craters and their distances from the Finsen crater center were calculated,and the thickness distribution of Finsen ejecta on the Von Kármán floor was systematically investigated.The boundary between Finsen ejecta and underlying mare basalt at the CE-4 landing site is constrained to a depth of 18 m.We have proposed the stratigraphy for the CE-4 site and interpreted the origins of different layers and the geological history of the Von Kármán crater.These results provide valuable geological background for interpreting data from the Lunar Penetrating Radar(LPR)and Visible and Near-infrared Imaging Spectrometer(VNIS)on the Yutu-2 rover.The CE-4 landing site could provide a reference point for crater ejecta distribution and mixing with local materials,to test and improve ejecta thickness models according to the in situ measurements of the CE-4 LPR.
基金Supported by National Key Research and Development Program of China(2020YFE0202100)。
文摘On 3 January 2019,the Chang’E-4 probe successfully landed in the Von Kármán crater in the South Pole-Aitken Basin on the far side of the Moon.On 4 January,the Yutu-2 rover was successfully separated from the lander and the scientific payloads were powered on to conduct scientific exploration.It was the first time that manmade probe achieved soft landing and roving on the far side of the Moon.Based on the data obtained by scientific payloads on the Chang’E-4,the research team obtained geological information such as landing area topography,structure and composition;demonstrated the existence of deep materials—mainly olivine and low-calcium pyroxene in the South Pole-Aitken Basin;achieved high-precision imaging of the layered structure of lunar subsurface in the roving area;discovered carbonaceous spheroidal meteorite residues and impact glass;preliminarily revealed the geological evolutionary history of the South Pole-Aitken Basin;for the first time,obtained information of the radiation dose of energetic particles at the lunar surface and the structure of the lunar neutral atomic energy spectrum;discovered the lunar mini-magnetosphere and contributed new knowledge of the radiation hazards at the lunar surface.This article summarizes the latest scientific achievement from the Chang’E-4 mission over the past three years.
文摘China has successfully launched six lunar probes so far.From Chang'E-1 to Chang'E-4,they completed the circling,landing and roving exploration,of which Chang'E-4 was the first landing on the far side of the Moon in human history.Chang'E-5 was launched in December 2020,bringing back 1731 g of lunar soil samples.Through the detailed analysis of the samples,the scientists understand the history of late lunar volcanism,specifically extending lunar volcanism by about 800 million to 1 billion years,and proposed possible mechanisms.In addition,there are many new understandings of space weathering such as meteorite impacts and solar wind radiation on the Moon.China's first Mars exploration mission Tianwen-1 was successfully launched in July 2021.Through the study of scientific data,a number of important scientific achievements have been made in the topography,water environment and shallow surface structure of Mars.This paper introduces the main scientific achievements of Chang'E-4,Chang'E-5 and Tianwen-1 in the past two years,excluding technical and engineering contents.Due to the large number of articles involved,this paper only introduces part of the results.
基金supported by the National Natural Science Foundation of China(Grant Nos.42325406 and 42304187)the China Postdoctoral Science Foundation(Grant No.2023M733476)+3 种基金the CAS Project for Young Scientists in Basic Research(Grant No.YSBR082)the National Key R&D Program of China(Grant No.2022YFF0503203)the Key Research Program of the Institute of Geology and GeophysicsChinese Academy of Sciences(Grant Nos.IGGCAS-202101 and IGGCAS-202401).
文摘The Yutu-2 rover onboard the Chang’E-4 mission performed the first lunar penetrating radar detection on the farside of the Moon.The high-frequency channel presented us with many unprecedented details of the subsurface structures within a depth of approximately 50 m.However,it was still difficult to identify finer layers from the cluttered reflections and scattering waves.We applied deconvolution to improve the vertical resolution of the radar profile by extending the limited bandwidth associated with the emissive radar pulse.To overcome the challenges arising from the mixed-phase wavelets and the problematic amplification of noise,we performed predictive deconvolution to remove the minimum-phase components from the Chang’E-4 dataset,followed by a comprehensive phase rotation to rectify phase anomalies in the radar image.Subsequently,we implemented irreversible migration filtering to mitigate the noise and diminutive clutter echoes amplified by deconvolution.The processed data showed evident enhancement of the vertical resolution with a widened bandwidth in the frequency domain and better signal clarity in the time domain,providing us with more undisputed details of subsurface structures near the Chang’E-4 landing site.
基金Supported by National Key R&D Program of China(2020YFE0202100)Beijing Municipal Science and Technology Commission(Z181100002918003)。
文摘China’s Chang’E-4 probe successfully landed on 3 January 2019 in Von Kármán crater within the South Pole-Aitken(SPA)basin on the lunar far side.Based on the data acquired by the scientific payloads onboard the lander and the rover,the researchers obtained the related information such as the geologic and tectonic setting of the landing area,compositional characteristics of the landing surface materials,dielectric permittivity and density of the lunar soil.The experiments confirmed the existence of materials dominated by olivine and low-calcium pyroxene in the SPA basin on the lunar far side,which preliminary revealed the geological evolution history of the SPA basin and even that of the early time lunar crust,as well as the tectonic setting and formation mechanism of the materials in the lunar interior.The researchers also investigated the particle radiation,Linear Energy Transaction(LET)spectrum,and so forth on the lunar surface.The low-frequency radio observations were carried out on the lunar far side for the first time as well.This article summarizes the latest scientific results in the past years,focusing on the Chang’E-4 mission.
