After 10 years of “imitation of the moon soil”
Approaching Lunar Soil Research ④
The lunar environment has no air circulation, no wind, frost, snow, rain, and no obstruction on its back. It is like a huge telescope, recording the composition and landing time of supernovae jets.
Therefore, by measuring the content of related nuclides in supernovae at different depths of the moon, it is possible to track the explosion history of near-Earth supernovae.
In late summer and early autumn, 200 milligrams of lunar scientific research samples came to the laboratory of China University of Geosciences (Wuhan), which made the researchers excited and excited.
"These samples are too precious, and they may bring many new breakthroughs to our research." said Wang Zaicong, a professor at the School of Earth Sciences, China University of Geosciences (Wuhan). Non-destructive experiments test certain physical properties of the lunar soil.
What is the composition of lunar soil?
What is the significance and value of studying the lunar soil?
What important information will the "young" lunar research samples provide for my country's lunar research?
Researchers hope to find the answer in the follow-up research that will be carried out immediately.
The "young" lunar soil is of great scientific value
"Most of the lunar samples obtained during the Apollo era are ancient samples more than 3 billion years ago. The lunar samples retrieved by my country's Chang'e-5 this time are likely to be very'young' (more than 1 billion years ago) "Wang Zaicong said that this is the second time that mankind has obtained direct lunar scientific research samples, and it has great scientific value for describing the deep process and evolutionary history of the moon.
In order to protect the precious lunar scientific research samples, Wang Zaicong and his colleagues immediately plastic-encapsulated the samples as soon as they received them. At the same time, put enough desiccant in the sealed box to prevent the moisture in the air from affecting the samples.
According to Wang Zaicong, the 200 mg lunar sample will be studied in accordance with normal procedures through a non-destructive, less-destructive, and destructive analysis process to ensure maximum scientific research output.
"The lunar soil is all-encompassing and has great research value, so detailed observation must be carried out under a laboratory microscope." Wang Zaicong said that the lunar soil sample applied for this time is different from the lunar soil sample brought back by the American Apollo. The particle size is very small, with an average diameter of about 20 to 30 microns, which is much finer than human hair. The lunar soil particles are invisible to the naked eye.
Wang Zaicong’s team mainly conducts research from two main directions: First, the surface of the moon has been hit by many meteorites and will also be affected by space storms. The formation and transformation process of the lunar soil can be studied through samples; at the same time, it can also be analyzed by composition and micro-area. Exploring the magma process and the evolution history of the moon’s mantle is an issue of concern to the whole world.
In this sample, 50 mg of lunar soil can be used for detrimental studies.
"If we want to study the average composition of the lunar soil, we need to conduct destructive research to maximize the value of scientific research." He said that the composition of the lunar soil previously inferred by remote sensing and indirect means was not accurate, and now it is based on the Chang'e-5 number. The samples brought back can be compared with previous data to figure out what the composition of the lunar soil is.
"Many teachers in our school are doing related research. With their own samples, there will be more and better research opportunities." Wang Zaicong said, the school organizes a research team to make detailed research plans and try to keep the samples as low as possible. Attrition, as much as possible to obtain more scientific research information.
Ten years of simulating the lunar soil and finally see the truth
In the laboratory of China University of Geosciences (Wuhan), the reporter saw lunar soil like black sand, but compared to the sand on the earth, their particles are finer.
To Professor Xiao Long, a member of the flight control expert group of the Chang'e-5 drill subsystem, and Professor Xiao Long from the School of Earth Sciences, China University of Geosciences (Wuhan), Lunar Land is both familiar and unfamiliar.
"We have developed simulated lunar soil for Chang'e missions for nearly 10 years, and provided engineering units with nearly 100 tons of simulated lunar soil." Xiao Long said that knowing the nature of the lunar soil is one of the key factors for the success of lunar surface sampling. Therefore, it is necessary to develop a simulated lunar soil with similar properties to the lunar soil for the verification of sampling engineering technology.
Xiao Long introduced that his team started to do analog sampling in 2009.
From the geological analysis of the pre-selected landing area, to the search for similar rock types on the earth, and subsequent simulation development, many challenges were encountered.
"We conducted thousands of experiments and failed many times, but we finally completed all the work in 2017," he said.
Xiao Long said that Chang'e 5 adopts two sampling methods, namely, mechanical arm surface extraction and drilling tool drilling, which are mutual backups.
The expected total mass of the sample is about 2 kg, of which 0.5 kg is drilled and 1.5 kg is taken from the table. The actual sample mass is 1731 g.
"The understanding and research of the lunar soil is an indispensable foundation for scientific exploration of the moon, the establishment of a lunar base and the use of lunar resources in the future." Xiao Long said bluntly.
What is proud of is that Chang'e 5 landed near the Rumke Mountains in the northern part of the Moon Sea Storm Ocean, the largest on the front of the moon, a place that has never been visited by probes from other countries.
In Xiao Long's view, the landing site is far away from the previous landing sampling area, which can answer scientific questions that have not been solved in the past. The Rumk Mountain area has the "youngest" volcanic rock on the moon, and the lunar soil sample research here is of great significance.
From landing on the moon to collect soil, to dividing the "soil" research, Xiao Long said with emotion that deep space research is a testimony to the comprehensive national strength. Hubei scientific researchers look forward to obtaining innovative scientific research results from the 200 mg sample as soon as possible and gaining more. Surprise.
Wang Zaicong believes that this is the first time that my country has drilled samples from the surface of the moon to return. It is a manifestation of my country's scientific and technological strength and a rare opportunity for our scientific research.
Or will reveal the mystery of the origin of the moon
For a long time, human beings have paid great attention to the origin of the moon. There are multiple theories such as the split theory, the capture theory, and the collision theory. Scientists at home and abroad are in disagreement.
Wang Zaicong said that researchers can reveal the hidden scientific secrets of the moon through lunar soil research.
Wang Zaicong believes that the isotope content analysis of the lunar soil samples obtained this time, especially the long-lived radionuclide content analysis, can obtain the lunar soil isotope composition and its formation time, and speculate on the evolution process of the moon, which provides the key to the study of the origin of the moon. Data support.
"We have a clear scientific research goal." Wang Zaicong said, relying on the university's State Key Laboratory of Geological Process and Mineral Resources and the Institute of Planetary Science, the research team can do this scientific research task.
In addition, studying the lunar soil has other planetary scientific research value.
The lunar environment has no air circulation, no wind, frost, snow, rain, and no obstruction on its back. It is like a huge telescope, recording the composition and landing time of supernovae jets.
Therefore, by measuring the content of related nuclides in supernovae at different depths of the moon, it is possible to track the explosion history of near-Earth supernovae.
According to reports, the Institute of Planetary Science of China University of Geosciences (Wuhan) has been established for more than ten years and is committed to cutting-edge scientific issues in lunar and planetary scientific research.
Wang Zaicong said that deep space exploration is a manifestation of the country's comprehensive strength and an aspect of planetary science research.
The content of planetary science research is promising, and research ideas on Earth can also be extended to other planets. At present, such research is still relatively limited.
"Now, more and more young people are joining planetary science research, and our country has also established a first-level discipline to promote its development." Wang Zaicong said that in the future, we will focus on cultivating more young talents to explore planetary science together, for my country's follow-up lunar and deep space exploration. Provide scientific and technological support.
Our reporter Wu Chunxin