The Chang'e-5 lunar soil is the first lunar return sample obtained by humans in 44 years, and China has become the third country in the world to complete the lunar landing sample return.
Author: Yuan Chao
Close to the moon soil one gram, telemetry galaxy for ten thousand years. In 2004, China officially approved the "Chang'e" lunar exploration project. After completing the lunar exploration "orbit, fall, return" three-step lunar orbit and landing exploration, the Chang'e-5 probe landed near Mount Lümke in the northwest of the lunar storm ocean on December 1, 2020, collecting a total of 1731 grams of "lunar native products", and successfully returned to the Siziwangqi space landing site on December 17, 2020, completing China's first extraterrestrial object sampling and return mission, marking a major progress and breakthrough in China's lunar exploration project.
What scientific secrets are contained in the Chang'e-5 lunar soil samples? What research achievements have Chinese scientists achieved? Li Yang, deputy director of the Center for Lunar and Planetary Sciences at the Institute of Geochemistry of the Chinese Academy of Sciences, recently accepted an exclusive interview with the China News Agency's "East and West Question" to unveil the mysterious "veil" of the "Chang'e" lunar exploration.
The interview transcript is summarized below:
China News Service: What is the research value of the moon soil? How can we improve our understanding of the history of the moon's formation and evolution?
Li Yang: Lunar soil is a fine powder formed by the fragmentation, melting, vaporization, deposition, cementation, churning, etc. of rocks on the lunar surface under the action of small bodies, meteorite impacts, solar wind radiation, solar flare particles, Galactic cosmic rays and diurnal temperature differences. The average thickness of the lunar soil in the Lunar Sea area is about 5 meters, and the highland area is about 10 meters.
The lunar soil, which covers most of the lunar surface, is not only the direct object of human observation and remote sensing detection, but also the main carrier and target of landing and patrol detection and sampling return. Lunar soil research can not only provide us with a large amount of information on the history of lunar formation and evolution, but its physical, chemical and mechanical properties can also provide important support for the implementation of scientific and engineering tasks such as lunar landing and patrol exploration, as well as the construction of future lunar bases and the extraction and utilization of resources. At the same time, the results of the lunar research can also allow us to re-understand the formation and evolution process of the Earth and other celestial bodies in the solar system from the perspective of comparative planetology, and related analytical techniques can also be widely used in the research of samples such as Earth, Mars, and meteorites.
At the main event of the 2021 "China Space Day" held in Nanjing, Jiangsu Province, the lunar samples were physically exhibited. China News Service reporter Yang Bo photographed
China News Service: The Chang'e-5 probe landed near the Lyumk Mountains in the northern part of the lunar storm ocean, the largest lunar storm on the lunar surface, a place that landers from other countries have never visited. Could this also help us solve some of the big scientific questions that have been unanswered in the past?
Li Yang: The landing site of the Chang'e-5 probe is far from the sampling points of the previous Apollo and Soviet Luna lunar exploration projects in the United States, and according to the results of the previous impact crater statistical dating, there are relatively young lunar sea basalts exposed in the area. Therefore, through the study of the Chang'e-5 lunar soil, we can re-understand the formation and evolution history of the moon from the two dimensions of space and time.
Major scientific questions include how long the Moon's volcanic activity lasted, what factors contributed to the continuous eruption of basalt in the region, whether the region had the first appearance of Klipu Rock in the late stage of magmatic evolution, and what specific differences in the evolutionary process of the Chang'e-5 lunar soil compared to Apollo and Luna lunar soils.
According to the current research results, we know that the geological age of the lunar sea basalt in the Chang'e-5 landing area is about 2 billion years, which is about 800 million years later than the previous research results, refreshing the previous international understanding of the geological age of the lunar sea basalt. At the same time, further research results also show that there is no Klip rock outcrop in the area, and the radioactive elements and water content of the basalt are not significantly high. Therefore, the specific factors that cause the continuous eruption of lunar sea basalt in this area are still being studied.
The Chang'e-5 probe automatically samples on the lunar surface. Courtesy of China National Space Administration
China News Service: What research work is currently on the Chang'e-5 lunar samples? What are the key research directions of the Institute of Geochemistry, Chinese Academy of Sciences? What is the significance?
Li Yang: At present, three batches of Chang'e-5 lunar samples have been publicly applied for and distributed, involving a wide range of research contents. It mainly includes the determination of the geological age of the basalt mentioned above, etc., and also includes the mineral composition of the lunar soil, the composition of elements and isotopes, and the weathering characteristics. The Institute of Geochemistry of the Chinese Academy of Sciences has a good preliminary foundation in the study of extraterrestrial samples such as lunar soil, and the main research contents include: the formation and evolution of the lunar crust, the volcanicity of the moon and the eruption of basalt, the formation of lunar soil and the history of spatio-temporal evolution, the dust environment on the lunar surface, the lunar space environment and the process of surface matter, the solar wind genesis water, etc., and it is expected to achieve a series of innovative research results. The above research work will provide an important basis and support for us to understand the formation and evolution history of the moon, the evolution history of the space environment on the lunar surface, and the development of lunar exploration projects.
China News Service: Why is everyone more enthusiastic about the study of chang'e-5 lunar samples?
Li Yang: First of all, the lunar and deep space exploration projects are the concentrated embodiment of comprehensive national strength and the commanding heights of scientific and technological competition among space powers. The Chang'e-5 lunar soil is the first lunar return sample obtained by humans in 44 years, and China has become the third country in the world to complete the lunar landing sample return. Every Chinese is proud of the country's prosperity and technological progress. Secondly, as a scientific and technological worker, it is an honor and a responsibility to be able to personally participate in the research work of lunar samples, and using our country's own lunar samples to achieve first-class research results is an excellent opportunity to reflect the level of research. In addition, the lunar sample also has great scientific value, which can extensively and deeply stimulate the enthusiasm of the majority of citizens, especially college, middle and primary school students, to understand the moon and the solar system, and then cultivate reserve talents for the long-term development of China's planetary science and deep space exploration projects.
Visitors visit the "Lunar Sample 001" exhibited at the National Museum of China. Photo by Shi Chunyang, China News Service
China News Service: What are China's long-term plans for lunar exploration? What are the relevant international arrangements?
Li Yang: In the future, the fourth phase of China's lunar exploration project plans the chang'e 6, 7 and 8 lunar exploration projects, and the manned lunar landing mission is also actively and deeply demonstrated. The United States plans to explore the lunar polar region and the lunar orbital space station plan, while Russia plans to verify the landing and working environment of the lunar polar region through the lunar -25, 26 and 27 three-time exploration plan, laying the foundation for the future site selection and construction of the lunar base. In addition, the United Kingdom, the European Space Agency, India, Israel and other countries have also planned their own lunar exploration programs. We live in an era of prosperity and strength, and how to contribute our own strength in the fierce international competition is the unshirkable responsibility and obligation of each and every scientific and technological worker.
Respondent Profiles:
Yang Li is a project researcher. He graduated from the University of Chinese Academy of Sciences in May 2013 with a Doctor of Science degree in astrochemistry. In September 2013, he entered the Institute of Geochemistry of the Chinese Academy of Sciences, and is currently the deputy director of the Center for Lunar and Planetary Sciences and the director of the Public Technical Service Center of the Institute of Geochemistry of the Chinese Academy of Sciences. Deeply involved in China's lunar and asteroid exploration projects.
Source: China News Network