27.06.2024

After the Chang'e-6 mission brought home the world's first samples collected from the moon's far side on Tuesday, Chinese scientists eagerly look forward to conducting research on the samples to uncover more mysteries of the moon.

"The Chang'e-6 mission represents a significant milestone in the history of human lunar exploration, and it will contribute to a more comprehensive understanding of lunar evolution," said Yang Wei, a researcher at the Institute of Geology and Geophysics of the Chinese Academy of Sciences (CAS).

"New samples will inevitably lead to new discoveries. Fascination with the moon is rooted in Chinese culture down the ages. Chinese scientists are eagerly anticipating the opportunity to contribute to lunar science," Yang added.

Lunar samples brought by the earlier Chang'e-5 mission have already drawn applications for access from international scholars, with the process well underway. The Chang'e-6 lunar probe carried four international payloads that were developed jointly by Chinese and foreign scientists. It is conceivable that the openness of Chinese lunar exploration activities will be mirrored in the study of Chang'e-6 lunar samples, Yang said.

As the moon's revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far side or "dark side" of the moon. This term doesn't refer to visible darkness, but rather the mystery shrouding the moon's largely unexplored terrain.

Remote-sensing images show the moon's two sides are very different, including lunar crust thickness, magma activities and compositions.

The reason why the near side and the far side of the moon are so different remains one of the greatest mysteries of the moon, said Lin Yangting, another scientist from the CAS Institute of Geology and Geophysics.

"Through the analysis and research of the Chang'e-6 samples, we could have a comprehensive understanding of the moon, filling many gaps in our knowledge and addressing significant scientific questions," Lin said.

The Chang'e-6 probe landed and collected samples in an impact crater known as the Apollo Basin, located within the South Pole-Aitken (SPA) Basin on the far side of the moon.

The colossal SPA Basin was formed by a celestial impact over 4.3 billion years ago and has a diameter of 2,500 km, equivalent to the distance from Beijing to Hainan, and a depth of about 13 km. It is believed to be the largest impact crater found in the inner solar system so far.

Compared to Chang'e-5, the landing and sampling site of Chang'e-6 has a complex geological structure, and the samples collected are likely to be mixtures, including in-situ basalt as well as materials ejected from surrounding areas due to the impact of small celestial bodies, Lin said.

"China's Chang'e-5 mission in 2020 initiated a new phase of in-depth studies on lunar samples after a 44-year hiatus, advancing our understanding of the moon's evolution," said Li Xianhua, an academician of the CAS.

However, prior to the Chang'e-6 mission, all ten lunar sampling missions in human history, including the Chang'e-5 mission, took place on the near side of the moon.

"Our current knowledge of the moon primarily comes from research on samples collected from its near side, which does not represent a comprehensive scientific understanding of the whole moon," Li said.

For the first time in human history, samples were retrieved from the far side of the moon. The international scientific community has shown unprecedented interest in the samples returned by the Chang'e-6 mission, Li said.

The Chang'e-6 samples will be of great significance in studying the two-faced moon, which is crucial for understanding this celestial body, according to Li.

"We have never conducted a detailed study of the SPA Basin before. The exact time of the impact that formed the SPA Basin and the consequences of the impact are subject to investigation. Scientists have numerous theoretical speculations, but need analysis of the samples to test these hypotheses," Li said.

The impact was so huge that materials from the lunar lower crust or even upper mantle deep beneath the surface might have been brought up, which were usually difficult to obtain. "The Chang'e-6 samples are of great significance for our understanding of the formation and early evolution of the moon," Li noted.

In addition, the landing site of the Chang'e-6 mission was on a basalt formed by volcanic activity. Volcanic activities on the far side of the moon were relatively rare compared with the near side, and it would be intriguing to study and compare the volcanic activities on both sides of the moon, Li said.

"We have long anticipated the samples from the far side of the moon. Since the beginning of this year, our institute has organized a team for the research on the Chang'e-6 samples. We held seminars every week to discuss the related scientific questions and plan our research in advance," Li added.

"We recently also invited experts from other institutions who specialize in lunar studies to join us for discussions. The venue, which can accommodate 200 people, was packed, with many enthusiastic participants standing," Li said.

Scientists have selected scientific problems they deemed most important, such as the origin of lunar asymmetry, the composition of the lunar deep crust or mantle, the formation time of the SPA Basin and the Apollo Basin, the volcanic history of the lunar far side, the water content, and discovery of new minerals or rocks on the moon.

Quelle: Xinhua

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Update: 15.08.2024

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Feature: China's "little photographer" on far side of the moon

On the desolate surface of the moon, a shimmering spacecraft with a long robotic arm appears dazzling against the backdrop of the black sky, while the faint line of a rut is visible on the lunar soil.

When the China National Space Administration released this picture after China's Chang'e-6 probe collected the first samples from the far side of the moon in June, it went viral across Chinese social media platforms, arousing people's curiosity as to how the photo was taken. Chinese space engineers recently revealed the "secret photographer."

The "photographer" is not a person, but an autonomous, intelligent mini robot weighing less than five kilograms that was attached to the lander of the Chang'e-6 during the mission's journey to the moon, according to the China Aerospace Science and Technology Corporation (CASC), its developer.

After Chang'e-6 collected its lunar samples, the mini robot autonomously detached from the lander, moved to a suitable position, selected an ideal angle for the photograph, and then captured the image.

As the world's first autonomous intelligent robot to land on the far side of the moon, it is highly capable and has significantly enhanced autonomous intelligence despite its compact size, according to the CASC.

Equipped with artificial intelligence technologies based on neural networks, the robot can think and judge like a human, said Xing Yan, a researcher with the CASC. It can accomplish many tasks that are not possible with traditional methods, such as adjusting the camera angle, she said.

Traditional lunar photography missions require meticulous calculations to determine the relative distance, position and ideal timing for capturing images. However, on the Chang'e-6 mission, the robot did not need exact computations. Instead, it autonomously assessed and refined its approach based on the quality of the images it captured, thereby ensuring the optimal visual outcome.

To accumulate the necessary experience, it requires extensive learning in autonomous intelligence development. The researchers prepared a variety of lights to help the robot learn and adapt to the unique lighting conditions on the far side of the moon, where the light source is singular and the backdrop is the inky expanse of space, said Huang Huang, another researcher of the CASC.

She still remembers her online shopping spree, purchasing a variety of lights such as fishing lamps, camping lamps, stage lights, all in an effort to broaden the mini robot's exposure to diverse lighting conditions.

The researchers developed a feature model of the environment based on the lights. By immersing the robot in this setting, they facilitated its learning process, ultimately achieving intelligent photographic decision-making.

Besides having a clever mind, the mini robot also boasts a robust "physique" to cope with the complex environment on the far side of the moon.

In contrast to the moon's near side, which is relatively flat, the far side features a more complex terrain, characterized by more mountains, deep valleys and craters.

Researchers conducted numerous simulation experiments with the mini robot working on special types of terrain.

The research team had to repeatedly adjust the structure and technical details of the mini robot to meet the requirements for the Chang'e-6 mission. At times, the relentless string of setbacks cast doubt on their design principles, Xing said.

"However, no matter how challenging, exhausting or stressful the situation was, we managed to calm ourselves down and address the issues first," she said.

Despite its great technological complexity, the mini robot is cost-effective to produce. As the technology matures, the potential applications for the future are diverse.

It can be reconfigured into a variety of forms, such as a floor-sweeping robot, a household assistant, a companion robot and an educational robot. It is also capable of performing inspections in confined spaces like narrow caves or pipelines, Xing said.

As deep-space exploration targets extend further and further away, autonomous intelligence will become a key technology in China's deep-space exploration endeavors, said Li Yong with the CASC.

For many deep-space missions, current telemetry and control technologies fall short of coverage. The uncertainty of the terrain to be explored dictates that many activities must be independently carried out by the probe itself, he said.

Quelle: Xinhua