Highlighting the work of Shanghai scientists on the Chang’e-5 mission

Ti Gong

Ti Gong

The world is now waiting for the return of the first lunar champions in 44 years. In the first attempt to return the sample to China, local researchers are putting their backs behind the wheel.

Traveling 380,000 kilometers in seven days, China’s sixth lunar mission Chang’e-5 landed on Oceanus Procellarum, or “Ocean of Storms,” ​​a previously unvisited area in a massive lava plain on the near side of the moon, on 1 December.

After a 19-hour operation, he finished collecting, packaging and sealing samples of lunar soil and rock. A spacecraft carrying the samples took off from the lunar surface on December 3 and is expected to return home in mid-late December.

If successful, China will also be the third nation to bring lunar champions to Earth after the United States and the former Soviet Union. Additionally, it will be the first to bring lunar samples to Earth in 44 years after the former Soviet Union’s Luna 24 mission in 1976.

The spectrometer developed by the Shanghai Institute of Technical Physics of the Chinese Academy of Sciences scanned the entire sampling area, providing scientific data useful for research in lunar science.

It works based on sunlight reflected on the moon. It can tell the distribution of minerals in the sampling area and reveal the mineral composition of the samples, according to He Zhiping, a researcher at the institute.

“No man has ever walked into the sampling area,” he said. “It is a virgin land that shows the moon in the wild. So, before and after sampling, the mineral composition of the lunar soil on the surface and subsoil may show some differences, the spectral data can help us understand the evolution of the moon.” .

Compared to the on-board predecessors Chang’e-3 and Chang’e-4, the latest generation features an extended wavelength range, which allows it to detect hydroxyl in hydrates.

“It probably provides a useful reference for finding traces of water and hydroxyl on the moon,” he said.

Also, it can automatically rotate to detect what it wants to detect in a certain range.

The other state-of-the-art payloads developed by the institute function as “laser radar to avoid obstacles” to ensure the probe’s soft landing, according to Shu Rong, deputy director of the institute.

Chang’e-5 successfully avoided hitting rocks and craters on the lunar surface by moving 6 meters parallel and made a stable and soft landing.

When it was about 20 kilometers above the moon, the laser range sensor began its work, mapping the height to the moon’s surface. When it was 2.5 kilometers above, the laser speed sensor began measuring the lander’s descent rate. When it was just 100 meters above, a 3D image sensor provided 3D images of the landing area, according to Xu Weiming, a researcher at the institute.

“This time, we have reduced the weight of other payloads by 30 percent to make room for the laser speed sensor,” he said. “It’s an emerging technology that can detect very small speed changes, even as low as 0.1 meters per second.”

Other Shanghai institutes under the DAC also contributed to the investigation.

CAS’s Shanghai Astronomical Observatory is using the Very Long Baseline Interferometry to track and position Chang’e-5 on its 23-day journey.

China’s VLBI system consists of a VLBI center and four stations in Shanghai, Beijing, Kunming in the southwestern province of Yunnan, and Urumqi in the northwestern Xinjiang Uyghur Autonomous Region. They form a gigantic “telescope” with a diameter of over 3,000 kilometers.

The system allows researchers on Earth to have immediate access to Chang’e-5’s exact location.

The journey to the moon is difficult. Spacecraft are exposed to an extremely harsh environment where temperatures can rapidly fluctuate from 100 degrees Celsius above zero to 100 degrees below zero.

Then, the CAS Shanghai Institute of Organic Chemistry designed thermal control coatings for the spacecraft. Coatings characterized by different levels of solar absorption and thermal emission.