One year since the moon was dug | A full explanation of my country's first lunar sample return mission

To celebrate the 100th anniversary of the founding of the Communist Party of China and encourage young people to learn about aerospace science, the China Aerospace Science Popularization Media Platform and Liaoning's "New Youth" magazine have launched the column "A Tribute to the 100th Anniversary of the Founding of the Party - A Tour of China's Aerospace Science and Technology Achievements" to tell young people about the achievements of China's aerospace science and technology.

On November 24, 2020, the Chang'e-5 lunar probe set off from the Wenchang Space Launch Center in Hainan and began its lunar sampling and return mission. On December 17, the Chang'e-5 lunar probe successfully landed in the designated area of ​​Siziwang Banner, Inner Mongolia, carrying 1,731 grams of lunar samples. my country's first lunar sampling and return mission was successfully completed. So, when did China start exploring the moon? Why explore the moon? What is Chang'e-5's lunar sampling and return journey like? Read on to find out.

Since ancient times, the Chinese nation has been full of fantasy and yearning for the moon. In ancient times, people could only look at the moon from the earth and observe it from afar. So they sang about the moon and expressed their feelings in poetry; they recorded that there were records of lunar eclipses in the oracle bones of the Shang Dynasty; they observed and formulated the lunar calendar and discovered that the tides were inseparable from the moon... It is even difficult for us today to imagine how our ancestors summarized and concluded after observing the moon thousands of times.

Although the long river of history has been rolling forward, the Chinese people have always had the same feelings for the moon. Today, China's space exploration has ranked among the world's top in lunar exploration, and has launched multiple lunar probes, completed orbiting the moon, landing on the moon, patrolling the moon, sampling the moon, and returning to the moon, with constant excitement and achievements. So, how did our journey to the moon begin?

It all started with a small rock from the moon

On May 28, 1978, Zbigniew Brzezinski, the US President's National Security Advisor, gave us a special gift when he visited China - a fingertip-sized lunar rock sample. This tiny lunar rock weighs only 1 gram and is a small part of the lunar rock samples brought back from the moon by astronauts carrying out the Apollo manned lunar mission.

This was the first time that the Chinese had come into contact with a real moon rock. Although it was only a small piece, it came from the moon, which made the Chinese people, who have accumulated thousands of years of lunar exploration, feel excited. They were eager to know which mission of the US Apollo project this moon rock came from, which part of the moon it was taken from, what its composition was, etc. The US did not provide detailed information on this information, as they wanted to use this moon rock to test our testing capabilities and research level.

So, which of the six manned lunar missions did this moon rock come from? You know, during these six manned lunar exploration missions, American astronauts brought back a total of 382 kilograms of moon rock and lunar soil samples.

To understand this moon rock, in-depth research is needed. Therefore, 1 gram of the moon rock was handed over to scientific research institutions for related research. At that time, there were still few scientists in my country who studied celestial rocks. After discussions among nearly 100 experts from various fields across the country, they decided to take only half of the moon rock for research, and the other half was sent to the Beijing Planetarium for exhibition. To this day, people can still see the other half of the moon rock that was preserved in the Beijing Planetarium.

A half-gram of moon rock preserved in the Beijing Planetarium

Experts carefully tested and analyzed the half-gram moon rock. They determined the mineral composition, structure, trace elements, chemical composition, physical properties, production environment and formation conditions of the moon rock. Finally, the experts concluded that the moon rock came from the sample collected by the Apollo 17 spacecraft. After referring to the data published by the United States, they also determined where on the moon the moon rock was collected and what the lighting conditions were.

Experts open the 1 gram moon rock donated by the United States

Despite the fruitful results, the Chinese people are more looking forward to exploring the moon with their own strength. After decades of unremitting efforts, in 2004, my country's lunar exploration project was finally approved! The Chinese lunar exploration project was named "Chang'e Project", and the Chinese people's thousand-year dream of exploring the moon was about to be realized.

The Chang'e Project logo is a dragon with calligraphy features

A pair of footprints outline the word "moon"

As the inheritors of Chinese civilization, we stand on the shoulders of our predecessors, constantly climbing to new heights and marching towards the moon! Over the past 17 years, step by step, the Chinese have relied on their own strength to complete the three steps of the lunar exploration project - "orbiting", "landing" and "returning", achieving lunar orbit exploration, lunar soft landing and patrol exploration, and lunar sampling and return exploration. After doing so much, why do we want to explore the moon? In addition to being a dream since ancient times, what can the huge cost and difficulty of lunar exploration bring us?

Why do we explore the moon?

1

National development needs

Lunar exploration is a reflection of a country's comprehensive national strength. The implementation of lunar exploration projects has great significance in terms of economy, science and technology, and national development strategy. At the same time, it can also inspire people's aspirations, boost national spirit, stimulate national pride, and enhance national cohesion.

2

Learn more about the Earth and the Moon

There is almost no atmosphere and geological activity on the moon, and it has not been transformed or destroyed. Therefore, lunar exploration activities can help us understand the formation, evolution and structure of the moon, and from this we can understand the origin and evolution of the earth, and deepen our understanding and knowledge of the earth and the moon.

3

Leading the development of high-tech

Lunar exploration can promote the innovation and development of disciplines, such as lunar science, space astronomy, materials science, etc., and drive the common development of more disciplines. Lunar exploration will also promote the development of aerospace engineering system integration, deep space exploration communications, space launch and other technologies, and drive the development of high-tech technologies such as information technology, artificial intelligence, remote sensing and telemetry, and new energy technologies, thereby indirectly driving the overall development of science and technology.

4

Preparing for the development of lunar resources

The development and utilization of lunar resources will have a profound impact on the sustainable development of human society. Lunar exploration can prepare for the future development and utilization of lunar resources by humans. For example, the helium-3 resource on the moon is a nuclear fusion fuel with a reserve of at least one million tons, which can be used by humans for more than 10,000 years, while there are only 10 to 15 tons on Earth.

5

Conducting space astronomical observations

Since there is no atmosphere on the moon, it is an ultra-vacuum environment, so astronomical observations can be easily carried out, such as ultraviolet astronomical observations that cannot be carried out on Earth. The back of the moon is always facing away from the Earth, and will not be disturbed by various activities on Earth, low-frequency noise, and human activities. It is a "pure land" that can obtain more real cosmic information.

There are so many benefits to lunar exploration, no wonder all the space powers are flocking to it! China's lunar exploration project also ushered in a "highlight moment" last year. The lunar probe Chang'e 5 completed my country's first lunar sampling and return mission, bringing back 1.7 kilograms of lunar samples for the first time. So, what was Chang'e 5's exciting lunar exploration journey like?

Chang'e 5's "digging" journey

On November 24, 2020, the Long March 5 carrier rocket carrying the Chang'e 5 lunar probe was successfully launched at the Wenchang Space Launch Center, marking the start of my country's first lunar sample return trip! So, what are the steps of this lunar exploration trip? Now, let's start a round-trip trip to the moon with Chang'e 5!

1

The first step of a journey is to reach your destination!

Chang'e 5 departed from the Wenchang Space Launch Center and directly entered the Earth-Moon transfer orbit and flew to the moon. After arriving near the moon, Chang'e 5 will first "brake", ignite the brakes and fly around the moon, gradually slowing down in preparation for landing on the moon.

Unlike Chang'e 3 and Chang'e 4, which only consist of a lander and a rover, Chang'e 5 consists of an ascender, a lander, an orbiter, and a returner. When landing on the moon, the ascender and lander combination first disconnected from the orbiter and returner combination, and headed towards the lunar surface from the orbit around the moon. Then, the lander carried the ascender to land in the Rumker Mountains in the northwest of the lunar front.

The composition of Chang'e 5

2

The second step of the trip is to shop, eat, and eat!

The Chang'e-5 lander uses a deep-hole drilling sampler and a shovel-type composite functional sampler to collect lunar samples, and then packages the samples. After packing the luggage, it's time for the ascender to work! The ascender is launched from the moon with the lunar samples and returns to the lunar orbit. There, the combination of the orbiter and the returner has been waiting for a long time.

Schematic diagram of Chang'e 5 sampling on the lunar surface

Afterwards, the ascender will dock with the orbiter and returner combination and transfer the samples to the interior of the returner. At this time, the ascender can retire, and after discarding the ascender, the orbiter and returner will leave the moon and embark on the journey home.

3

The last step of the trip is to bring home some souvenirs!

After Chang'e 5 flew back to the vicinity of the Earth, the orbiter also made a perfect curtain call. Finally, the returner took the samples and played "skipping stones" at the "doorstep" to reduce the flight speed, ensuring that the speed was not too high or too low, and could smoothly enter the Earth's atmosphere. After passing through the "passionate baptism" of the atmosphere and landing on the Inner Mongolia prairie, Chang'e 5's mission was successfully completed.

Schematic diagram of the separation of Chang'e 5 orbiter and returner

Doesn't Chang'e 5's lunar exploration look very interesting? After Chang'e 5, we will also launch Chang'e 6, Chang'e 7, and Chang'e 8, not only to "dig soil" on the moon again, but also to visit the South Pole of the moon.

In the future, we will work with other major space powers and space powers to jointly develop and build an international lunar research station that can operate autonomously for a long time. Are you looking forward to it?

Editor/Yang Sishuang

Review/Yang Jie

Producer/Cao Xiaoyong

Source: China Aerospace Science