Long rocket from March 5th

China has launched its most advanced mission to the moon to date

By Donna Lu

This March 5th long rocket will launch China’s Chang’e 5 lunar probe

Photo by STR / AFP via Getty Images

China launched its Chang’e 5 spaceship on November 23 in the first mission to return moon rocks to Earth in more than four decades.

The unscrewed Chang’e 5 probe will attempt to collect at least 2 kilograms of lunar dust and debris from the northern region of Oceanus Procellarum, a previously unvisited area on the near side of the moon.

If the Chang’e 5 return mission is successful, China will be the only third country after the US and the Soviet Union to have sampled the moon. The last sample return mission was carried out in 1976 by the Luna 24 robotic probe of the Soviet Union, which returned around 170 grams to Earth.

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Chang’e 5 was launched early Tuesday morning, Beijing time, from a March 5 rocket at a location in Wenchang on Hainan Island in the South China Sea. The spaceship consists of an orbiter, a re-entry capsule, and a lander and ascent stage. After Chang’e 5 reaches lunar orbit, the lander and ascent stage will separate from the main spaceship to touch down on the moon.

Given that many factors can affect the actual landing point of the probe, the Chinese space agency has selected a large potential landing area near Mons Rümker, a 1,300-meter-high volcanic formation, said Long Xiao of the Chinese University of Geosciences in Wuhan, who helped suggest candidate sites for the mission.

“The landing site comprises two different geological units,” says Xiao. In the west, the basalts – rock formed by the rapid cooling of the lava – are similar to those removed in the Apollo missions. Chang’e 5 aims to land east of Mons Rümker in an area that appears to contain much younger rock that is around 1.2 to 2 billion years old.

“These would be the most recent volcanic samples ever returned from the moon,” says Catherine Neish of Western University in Ontario, Canada. “This is an extremely exciting mission.”

In the Apollo missions, which consisted of six moon landings between 1969 and 1972, astronauts brought 382 kilograms of lunar rock back to earth. The samples returned from the Apollo missions are between 3.1 and 4.4 billion years old.

Once Chang’e 5 lands, two sampling methods will be used, a major improvement over Luna 24, says James Head of Brown University in Providence, Rhode Island. First, the lander will drill and collect a core of regolith about 2 meters deep – loose soil and broken stones. A robotic arm also picks up flat floors on the surface. While the goal is to collect at least 2 kilograms of samples, Chang’e 5 has a maximum sample capacity of around 4 kilograms.

The lander is also equipped with a visible near-infrared spectrometer and ground penetrating radar, which can be used to assess the composition of the ground below. “The moon’s ground penetrating radar is critical to correlating the structure and layers of the lunar soil and understanding its origin,” says Head.

Unlike the previous Chang’e spaceship, Chang’e 5 is not equipped with heating devices to withstand the extreme cold of the moonlit night. Therefore, the sampling has to be done on a single lunar day – approximately 14 earth days.

Once Chang’e 5 completes its surface operations, the samples will be stored in their ascent stage as they lift off from the moon and make contact with the orbiter again. The samples are then transferred to the re-entry capsule and the spacecraft exits lunar orbit. It is expected to land in Inner Mongolia in mid-December.

“Every time you land on the surface of another planet it is a challenge. However, this mission is more complex as a sample is collected, stowed and then lifted from the lunar surface to return to Earth,” says Kerri Donaldson Hanna of the University of Central Florida. “This is something that has not been done in the modern era of space exploration.”

If the Chang’e 5 mission is successful, the return of new samples will fill a large void in our understanding of the evolution of the moon.

“This will be really important information to understand the thermal evolution of the interior of the moon,” says Marc Norman of the Australian National University in Canberra.

If analysis shows the samples are as young as we believe – 2 billion years or less – that would shed some light on what happened on the moon at a time when it was cooling down and also turning off its magnetic field, says Neish.

The samples will also help researchers better calibrate the age of the moon’s surfaces based on the density of the impact craters. Older surfaces tend to have more and larger craters than younger surfaces.

“If we can tie an absolute age to the crater densities in this environment on the moon, we will have a really useful data point for geological mapping of other planets in the solar system,” says Norman.

Once the samples have returned to Earth, they will be stored in the National Astronomical Observatories of China in Beijing. “As part of the retention strategy, some samples are being kept permanently at Hunan University to avoid possible loss due to natural disasters,” says Head.

Due to the limited amount of lunar material, research laboratories that are successfully granted samples may be limited to certain types of analysis, e.g. B. Minerology or isotope studies, whereby non-destructive research methods must be applied first, says Xiao.

Chang’e 5 is part of the Chinese government’s four-phase lunar exploration program and likely a preparatory step to send Chinese taikonauts to the moon in the future, perhaps around 2030. “The Chinese are thinking about this very long term and very strategically about what they want to achieve by going to the moon and Mars,” says Norman.

Phase one – Chang’e 1 and 2 – involved orbital missions, while Chang’e 3 and 4 missions in phase two used soft landers and rovers. Phase three, sample return, consists of Chang’e 5 and Chang’e 6, which are scheduled to start in 2023 or 2024. In phase four the south pole of the moon is explored.

“The Chinese have had a good success rate on their Chang’e missions so far,” says Lionel Wilson of Lancaster University in the UK. “The Chang’e 4 landing was on the other side of the moon, where there was absolutely no way to make realistic last-minute corrections to the landing process from Earth, confirming that they have a robust landing system. I assume they will land successfully. ”

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