China's Chang'e-4 probe soft-lands on moon's far side - Xinhua
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Still active. What a technological achievement.
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China Science @ChinaScience
China state-affiliated media
China’s #Mars probe Tianwen-1 had travelled over 10 mln km away from Earth as of 10:45 pm Tue. China's Chang'e-4 lunar probe has survived 600 Earth days and rover Yutu-2 has moved 519.25m after completing the 21st lunar day mission on the far side of the Moon.
2:00 PM · Aug 26, 2020
China state-affiliated media
China’s #Mars probe Tianwen-1 had travelled over 10 mln km away from Earth as of 10:45 pm Tue. China's Chang'e-4 lunar probe has survived 600 Earth days and rover Yutu-2 has moved 519.25m after completing the 21st lunar day mission on the far side of the Moon.
2:00 PM · Aug 26, 2020
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Chang'e-4 probe's 600 days on the Moon brings large scientific gains
2020-08-27 15:14:55 CGTN Editor : Gu Liping
The far side of the Moon. /CNSA
The Yutu-2 rover of China's Chang'e-4 lunar probe has set a record by traveling over 500 meters during its 600 days of work on the far side of the Moon, according to the China National Space Administration (CNSA) on Wednesday.
The lander and the rover finished their work for the 21st lunar day and switched to the dormant mode for the lunar night on Tuesday. By this day, the rover traveled 519.29 meters in a new record.
Queqiao (magpie bridge) the relay satellite is in normal working condition.
Scientists have carried out extensive research based on the data transferred by the scientific payloads on the rover and achieved positive results.
Through data from the visible/near-infrared imaging spectrometer, panoramic camera and lunar radar, they analyzed the spectrum, rock distribution, and shallow structure of the landing zone, and drew scientific conclusions on the morphology, material mineral composition, source and characteristics of the landing area.
For the first time, the composition of deep lunar materials was obtained directly through in-situ exploration, revealing the complex geological evolution of the far side of the Moon, especially the South Pole-Aitken Basin where the probe landed last year. It provides key evidence of the formation and evolution model of lunar soil, and also important reference for site selecting for future lunar missions' landing, inspection and exploration.
Scientists also carried out the study on the shallow lunar surface structure in the patrol area, which can greatly improve human's understanding of the "history of lunar impact and volcanic activity," and provide new insights into its evolution.
Other results have been achieved from research on neutrons, radiation dose and neutral atoms on lunar surface, and low-frequency radio astronomical observation.
2020-08-27 15:14:55 CGTN Editor : Gu Liping
The far side of the Moon. /CNSA
The Yutu-2 rover of China's Chang'e-4 lunar probe has set a record by traveling over 500 meters during its 600 days of work on the far side of the Moon, according to the China National Space Administration (CNSA) on Wednesday.
The lander and the rover finished their work for the 21st lunar day and switched to the dormant mode for the lunar night on Tuesday. By this day, the rover traveled 519.29 meters in a new record.
Queqiao (magpie bridge) the relay satellite is in normal working condition.
Scientists have carried out extensive research based on the data transferred by the scientific payloads on the rover and achieved positive results.
Through data from the visible/near-infrared imaging spectrometer, panoramic camera and lunar radar, they analyzed the spectrum, rock distribution, and shallow structure of the landing zone, and drew scientific conclusions on the morphology, material mineral composition, source and characteristics of the landing area.
For the first time, the composition of deep lunar materials was obtained directly through in-situ exploration, revealing the complex geological evolution of the far side of the Moon, especially the South Pole-Aitken Basin where the probe landed last year. It provides key evidence of the formation and evolution model of lunar soil, and also important reference for site selecting for future lunar missions' landing, inspection and exploration.
Scientists also carried out the study on the shallow lunar surface structure in the patrol area, which can greatly improve human's understanding of the "history of lunar impact and volcanic activity," and provide new insights into its evolution.
Other results have been achieved from research on neutrons, radiation dose and neutral atoms on lunar surface, and low-frequency radio astronomical observation.
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3.5 Billion Years Old, Geologic Age of Finsen Crater on Farside of Moon Determined----Chinese Academy of Sciences
Editor: LI Yuan | Sep 04, 2020
The absolute model age (AMA), or geologic age of Finsen crater on the Moon’s farside is determined to be about 3.5 billion years (Ga) based on crater counting method, according to a study published in Icarus.
The study is conducted by a research team led by Prof. DI Kaichang from the State Key Laboratory of Remote Sensing Sciences, Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences (CAS).
Based on this model age, the regolith growth rate at the Chang'e-4 landing site and the crater degradation rate within Finsen crater have also been estimated.
China's Chang'e-4 probe, including a lander and a rover, successfully touched down the floor of Von Kármán crater within the South Pole-Aitken (SPA) basin on the farside of the Moon on January 3, 2019. Since then, Chang'e-4 rover has been traversing on the floor of Von Kármán crater and has carried out a string of in situ measurements along traverse with equipped scientific payloads.
Context map of Chang'e-4 landing site (Image by AIR)
Although multiple studies have revealed that Finsen crater ejecta is the primary source of materials measured inside of Von Kármán crater, where Chang’e-4 rover landed, the formation age of Finsen crater, which has significant geologic implications, is still at odds within the planetary community.
The team used Chang'e-2 digital orthophoto map (DOM) and digital elevation model (DEM) data in their research. They outlined a flat and homogenous area on the floor of Finsen as crater count area, and manually mapped craters in the outlined area.
Finally, the AMA of Finsen crater was determined by fitting the obtained crater size-frequency distribution (CSFD) to standard lunar cratering chronology. Both cumulative and differential fits revealed an AMA of ~3.5 Ga, indicating Finsen crater was Imbrium-aged.
Radar images indicated that the thickness of the Finsen crater ejecta-sourced fine-grained regolith at Chang'e-4 landing site was about 12 m. The team thus estimated the average regolith growth rate at the Chang'e-4 landing site was about 3.4 m/Gyr.
Compared with Apollo landing sites of similar age, the regolith growth rate at Chang'e-4 landing site was greater, except for Apollo 16, suggesting a low weathering resistivity of Finsen crater ejecta to the harsh space environment.
There are many simple craters on the floor of Finsen crater, which are easily degraded by erosion of crater rim and infilling of crater interior through geologic processes. The team further calculated the current depth of 25 largest craters within the outlined area through a profile-average-depth method and the estimated crater degradation rate within Finsen was about 21 ± 3 m/Gyr.
This degradation rate has the same order of magnitude to that on the lunar maria (about 32 m/Gyr), indicating lunar craters might have a similar degradation rate on a global scale.
However, the rate is much slower than that on other airless rocky bodies, for example, average degradation rate on Vesta is 350 m/Gyr, and on Gaspra is 100-1000 m/Gyr. One of the most likely reasons is that craters on asteroids are easily degraded or even erased by mass movements caused by impact-induced global seismic shaking.
Editor: LI Yuan | Sep 04, 2020
The absolute model age (AMA), or geologic age of Finsen crater on the Moon’s farside is determined to be about 3.5 billion years (Ga) based on crater counting method, according to a study published in Icarus.
The study is conducted by a research team led by Prof. DI Kaichang from the State Key Laboratory of Remote Sensing Sciences, Aerospace Information Research Institute (AIR) of the Chinese Academy of Sciences (CAS).
Based on this model age, the regolith growth rate at the Chang'e-4 landing site and the crater degradation rate within Finsen crater have also been estimated.
China's Chang'e-4 probe, including a lander and a rover, successfully touched down the floor of Von Kármán crater within the South Pole-Aitken (SPA) basin on the farside of the Moon on January 3, 2019. Since then, Chang'e-4 rover has been traversing on the floor of Von Kármán crater and has carried out a string of in situ measurements along traverse with equipped scientific payloads.
Context map of Chang'e-4 landing site (Image by AIR)
Although multiple studies have revealed that Finsen crater ejecta is the primary source of materials measured inside of Von Kármán crater, where Chang’e-4 rover landed, the formation age of Finsen crater, which has significant geologic implications, is still at odds within the planetary community.
The team used Chang'e-2 digital orthophoto map (DOM) and digital elevation model (DEM) data in their research. They outlined a flat and homogenous area on the floor of Finsen as crater count area, and manually mapped craters in the outlined area.
Finally, the AMA of Finsen crater was determined by fitting the obtained crater size-frequency distribution (CSFD) to standard lunar cratering chronology. Both cumulative and differential fits revealed an AMA of ~3.5 Ga, indicating Finsen crater was Imbrium-aged.
Radar images indicated that the thickness of the Finsen crater ejecta-sourced fine-grained regolith at Chang'e-4 landing site was about 12 m. The team thus estimated the average regolith growth rate at the Chang'e-4 landing site was about 3.4 m/Gyr.
Compared with Apollo landing sites of similar age, the regolith growth rate at Chang'e-4 landing site was greater, except for Apollo 16, suggesting a low weathering resistivity of Finsen crater ejecta to the harsh space environment.
There are many simple craters on the floor of Finsen crater, which are easily degraded by erosion of crater rim and infilling of crater interior through geologic processes. The team further calculated the current depth of 25 largest craters within the outlined area through a profile-average-depth method and the estimated crater degradation rate within Finsen was about 21 ± 3 m/Gyr.
This degradation rate has the same order of magnitude to that on the lunar maria (about 32 m/Gyr), indicating lunar craters might have a similar degradation rate on a global scale.
However, the rate is much slower than that on other airless rocky bodies, for example, average degradation rate on Vesta is 350 m/Gyr, and on Gaspra is 100-1000 m/Gyr. One of the most likely reasons is that craters on asteroids are easily degraded or even erased by mass movements caused by impact-induced global seismic shaking.
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Published result of Chang'E-3
Source: In Situ Investigations of Dust Above the Lunar Terminator at the Chang'E‐3 Landing Site in the Mare Imbrium - Li - 2020 - Geophysical Research Letters - Wiley Online Library
Plain Language Summary
It was postulated for several decades that the lunar horizon glow observed during Apollo epoch was caused by forward scattering of sunlight by the electrostatically levitated dust particles above the sharp sunlight/shadow boundaries in the terminator zone. However, do high concentrations of charged dust particles really exist over the lunar terminator? This question cannot be definitively answered at present. China's Chang'E‐3 (CE‐3) mission provided a unique opportunity to address this long‐standing scientific question because an in situ dust detector was loaded onto the lander. In this letter, the results obtained by the dust detector were demonstrated. It is found that the recently proposed minimalist model is not suitable for the geologically young CE‐3 landing site. Within detector's detection limit, no putative high‐density population of lunar dust particles was found above the sharp sunlight/shadow boundaries. This research, being carried out on the lunar surface rather than in orbit, can provide important new insights into the generation mechanisms about lunar horizon glow.
Source: In Situ Investigations of Dust Above the Lunar Terminator at the Chang'E‐3 Landing Site in the Mare Imbrium - Li - 2020 - Geophysical Research Letters - Wiley Online Library
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Ground-breaking probe reveals secrets on the moon's far side
Xinhua 00:16 UTC+8, 2020-09-09
Based on data from China’s Chang’e-4 lunar probe, Chinese scientists have determined the thickness of the regolith — the soil layer that covers the rocks — and examined the fine subsurface structures and evolutionary history of the probe’s landing site on the moon’s far side.
The study revealed that the landing area of the probe, within the largest and oldest impact basin on the moon, had experienced multiple impacts and basalt magma eruptions.
The Chang’e-4 probe, launched on December 8, 2018, made the first-ever soft landing on the Von Karman Crater in the South Pole-Aitken Basin on the far side of the moon on January 3, 2019.
Carrying scientific instruments including a lunar penetrating radar, the rover Yutu-2 has conducted scientific detection on the compositions of lunar surface materials and the subsurface structures.
Scientists from the Institute of Geology and Geophysics under the Chinese Academy of Sciences, the Aerospace Information Research Institute under the CAS, the Macau University of Science and Technology and other institutes have carried out research on the lunar penetrating radar onboard Yutu-2 during the first three lunar days and obtained important findings on the subsurface structure of the landing area.
The results showed that the materials detected by Yutu-2 come from the nearby Finsen crater rather than the basalt that erupted from the lunar mantle, which filled the bottom of the Von Karman Crater. It showed the landing area had experienced multiple impactss and basalt magma eruptions.
The discoveries are of great significance to understanding the evolutionary history of the South Pole-Aitken basin, as well as to the following exploration and research on the composition and structure of the lunar interior, said Lin Yangting, a researcher with the IGG.
Asteroid impacts were an important driving force for the early evolution of the Earth. However, the long-term geological tectonic activities have erased most of the traces of the impact cratering events on Earth.
The internal evolution of the moon has long ceased due to its small mass. Therefore, impact craters and the deposit profile of crater ejecta from eruptions on the lunar surface have recorded the impact history of asteroids in the earth-moon system.
According to Lin, the subsurface structure of the moon recorded the number and scale of large-scale impact events and magma eruptions, as well as their temporal and spatial relationships. However, the fine structure of the moon’s shallow layers remains a mystery to humans.
The modification of lunar surface materials by asteroid impacts has a direct influence on the results obtained from orbital observations and landing site reconnaissance, and affects how scientists will implement future lunar missions.
Xinhua 00:16 UTC+8, 2020-09-09
Based on data from China’s Chang’e-4 lunar probe, Chinese scientists have determined the thickness of the regolith — the soil layer that covers the rocks — and examined the fine subsurface structures and evolutionary history of the probe’s landing site on the moon’s far side.
The study revealed that the landing area of the probe, within the largest and oldest impact basin on the moon, had experienced multiple impacts and basalt magma eruptions.
The Chang’e-4 probe, launched on December 8, 2018, made the first-ever soft landing on the Von Karman Crater in the South Pole-Aitken Basin on the far side of the moon on January 3, 2019.
Carrying scientific instruments including a lunar penetrating radar, the rover Yutu-2 has conducted scientific detection on the compositions of lunar surface materials and the subsurface structures.
Scientists from the Institute of Geology and Geophysics under the Chinese Academy of Sciences, the Aerospace Information Research Institute under the CAS, the Macau University of Science and Technology and other institutes have carried out research on the lunar penetrating radar onboard Yutu-2 during the first three lunar days and obtained important findings on the subsurface structure of the landing area.
The results showed that the materials detected by Yutu-2 come from the nearby Finsen crater rather than the basalt that erupted from the lunar mantle, which filled the bottom of the Von Karman Crater. It showed the landing area had experienced multiple impactss and basalt magma eruptions.
The discoveries are of great significance to understanding the evolutionary history of the South Pole-Aitken basin, as well as to the following exploration and research on the composition and structure of the lunar interior, said Lin Yangting, a researcher with the IGG.
Asteroid impacts were an important driving force for the early evolution of the Earth. However, the long-term geological tectonic activities have erased most of the traces of the impact cratering events on Earth.
The internal evolution of the moon has long ceased due to its small mass. Therefore, impact craters and the deposit profile of crater ejecta from eruptions on the lunar surface have recorded the impact history of asteroids in the earth-moon system.
According to Lin, the subsurface structure of the moon recorded the number and scale of large-scale impact events and magma eruptions, as well as their temporal and spatial relationships. However, the fine structure of the moon’s shallow layers remains a mystery to humans.
The modification of lunar surface materials by asteroid impacts has a direct influence on the results obtained from orbital observations and landing site reconnaissance, and affects how scientists will implement future lunar missions.
JSCh
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Payloads on China's retired lunar probe still operating
Xinhua | Updated: 2020-09-10 09:20
Screen shows the photos of the Chang'e-3 moon lander (L) and the Yutu moon rover during the mutual-photograph process, at the Beijing Aerospace Control Center in Beijing, Dec 15, 2013. [Photo/Xinnhua]
BEIJING -- After more than 2,400 days on the near side of the moon, China's Chang'e 3 lunar mission continues to help scientists unravel the unknown about the Earth's companion in space.
As of Sept. 1, the Chang'e-3 lunar mission has been on the moon for 2,453 Earth days, and some of the scientific payloads carried by the lander are still operating, according to the Lunar Exploration and Space Program Center of the China National Space Administration.
After analyzing the transmitted data, Chinese researchers recently reported finding multilayered young lava flows in the northeast of Mare Imbrium, also called Sea of Rains, where the Chang'e-3 mission made a soft landing in December 2013.
The surface of the Moon features numerous large basins caused by bombardments of asteroids about 3.9 billion years ago. They were filled with dark basalt lava flows from volcanic eruptions. The eruptions produced successive layers of basalt stacked in a vertical sequence, which, scientists believe, harbors the history of the moon.
The lunar penetrating radar on board helps see below the surface.
Researchers from China University of Geosciences, Yangtze University, and Ningbo University of Finance and Economics reported that they ascertained three layers of thin young mare basalts underlying the lunar soil at Chang'e-3's landing site.
In previous studies, the region is thought to be formed by one layer of a thick lava flow.
The researchers calculated the spatial variation and distribution of thickness of each layer and built a 3D stratigraphic model of young mare basalts.
According to the researchers, the young lava flows in the northern Mare Imbrium probably erupted from the same source as that in the southwest.
The research findings have been published in the journal Geophysical Research Letters.
China's Chang'e-3 moon mission delivered the rover Yutu, or Jade Rabbit, and a stationary lander to the lunar surface on Dec. 14, 2013, marking the first moon landing since the Soviet Union's Luna 24 mission in 1976.
It touched down on the northern Mare Imbrium, a region not directly sampled before and far from the U.S. Apollo lunar landing sites.
Yutu traveled a total of 114 meters following a zigzagging route, before coming to a halt due to technical glitches.
The findings based on the data gathered by the mission have been published in leading international scientific journals.
Scientists believe that the lunar probe will help in understanding the early history of the earth as the earth and the moon share similar experiences in their origins. The early history of the earth, which has been erased by frequent geological activities, can be studied on the moon.
Xinhua | Updated: 2020-09-10 09:20
BEIJING -- After more than 2,400 days on the near side of the moon, China's Chang'e 3 lunar mission continues to help scientists unravel the unknown about the Earth's companion in space.
As of Sept. 1, the Chang'e-3 lunar mission has been on the moon for 2,453 Earth days, and some of the scientific payloads carried by the lander are still operating, according to the Lunar Exploration and Space Program Center of the China National Space Administration.
After analyzing the transmitted data, Chinese researchers recently reported finding multilayered young lava flows in the northeast of Mare Imbrium, also called Sea of Rains, where the Chang'e-3 mission made a soft landing in December 2013.
The surface of the Moon features numerous large basins caused by bombardments of asteroids about 3.9 billion years ago. They were filled with dark basalt lava flows from volcanic eruptions. The eruptions produced successive layers of basalt stacked in a vertical sequence, which, scientists believe, harbors the history of the moon.
The lunar penetrating radar on board helps see below the surface.
Researchers from China University of Geosciences, Yangtze University, and Ningbo University of Finance and Economics reported that they ascertained three layers of thin young mare basalts underlying the lunar soil at Chang'e-3's landing site.
In previous studies, the region is thought to be formed by one layer of a thick lava flow.
The researchers calculated the spatial variation and distribution of thickness of each layer and built a 3D stratigraphic model of young mare basalts.
According to the researchers, the young lava flows in the northern Mare Imbrium probably erupted from the same source as that in the southwest.
The research findings have been published in the journal Geophysical Research Letters.
China's Chang'e-3 moon mission delivered the rover Yutu, or Jade Rabbit, and a stationary lander to the lunar surface on Dec. 14, 2013, marking the first moon landing since the Soviet Union's Luna 24 mission in 1976.
It touched down on the northern Mare Imbrium, a region not directly sampled before and far from the U.S. Apollo lunar landing sites.
Yutu traveled a total of 114 meters following a zigzagging route, before coming to a halt due to technical glitches.
The findings based on the data gathered by the mission have been published in leading international scientific journals.
Scientists believe that the lunar probe will help in understanding the early history of the earth as the earth and the moon share similar experiences in their origins. The early history of the earth, which has been erased by frequent geological activities, can be studied on the moon.
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China's Chang'e-4 probe switches to dormant mode
Source: Xinhua| 2020-09-24 14:04:45|Editor: huaxia
BEIJING, Sept. 24 (Xinhua) -- The lander and the rover of the Chang'e-4 probe have been switched to dormant mode for the lunar night after working stably for a 22nd lunar day, according to the Lunar Exploration and Space Program Center of the China National Space Administration.
The lander was switched to dormant mode at 7:30 a.m. on Thursday (Beijing Time) as scheduled, and the rover, Yutu-2 (Jade Rabbit-2), at 11:18 p.m. on Wednesday, said the center on its official social media platform accounts.
A lunar day is equal to 14 days on Earth, and a lunar night is the same length. The Chang'e-4 probe, switching to dormant mode during the lunar night due to the lack of solar power, has survived 630 Earth days on the far side of the moon as of Thursday, and the rover has traveled 547.17 meters.
During the 22nd lunar day, Yutu-2 explored an impact crater about 1.3 km northwest of the landing site.
The Chang'e-4 probe, launched on Dec. 8, 2018, made the first-ever soft landing on the Von Karman Crater in the South Pole-Aitken Basin on the far side of the moon on Jan. 3, 2019.
Source: Xinhua| 2020-09-24 14:04:45|Editor: huaxia
BEIJING, Sept. 24 (Xinhua) -- The lander and the rover of the Chang'e-4 probe have been switched to dormant mode for the lunar night after working stably for a 22nd lunar day, according to the Lunar Exploration and Space Program Center of the China National Space Administration.
The lander was switched to dormant mode at 7:30 a.m. on Thursday (Beijing Time) as scheduled, and the rover, Yutu-2 (Jade Rabbit-2), at 11:18 p.m. on Wednesday, said the center on its official social media platform accounts.
A lunar day is equal to 14 days on Earth, and a lunar night is the same length. The Chang'e-4 probe, switching to dormant mode during the lunar night due to the lack of solar power, has survived 630 Earth days on the far side of the moon as of Thursday, and the rover has traveled 547.17 meters.
During the 22nd lunar day, Yutu-2 explored an impact crater about 1.3 km northwest of the landing site.
The Chang'e-4 probe, launched on Dec. 8, 2018, made the first-ever soft landing on the Von Karman Crater in the South Pole-Aitken Basin on the far side of the moon on Jan. 3, 2019.
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