China brought a capsule filled with lunar soil from the far side of the Moon to Earth on Tuesday, scoring the latest success in an ambitious program to explore the Moon and other parts of the solar system.
The sample, recovered by the China National Space Administration’s Chang’e-6 lander after a 53-day mission, highlights China’s growing capabilities in space and marks another victory in a series of lunar missions that began in 2007 and have so far been almost executed. flawless.
“Chang’e-6 is the first mission in human history to return samples from the far side of the Moon,” Long Xiao, a planetary geologist at the University of Geosciences of China, wrote in a letter. electronic. “This is a major event for scientists around the world,” he added, and “a cause for celebration for all humanity.”
Such sentiments and the prospects of international exchanges of lunar samples have highlighted hopes that Chinese robotic missions to the Moon and Mars will serve to advance scientific understanding of the solar system. Those possibilities are contrasted by views in Washington and elsewhere that Tuesday’s achievement constitutes the latest milestone in a 21st-century space race with geopolitical overtones.
In February, a private American spacecraft landed on the Moon. NASA is also continuing the Artemis campaign to return Americans to the lunar surface, even though its next mission, an astronaut flight around the Moon, has been delayed due to technical problems.
China is also looking to expand its presence on the Moon, landing more robots, and possibly human astronauts, there in the coming years.
To achieve this goal, she took a slow and steady approach, executing a robotic lunar exploration program that she designed decades in advance. Named after the Chinese moon goddess Chang’e (pronounced “chong-uh”), the program’s first two missions orbited the moon to photograph and map its surface. Then came Chang’e-3, which landed on the lunar side in 2013 and deployed a rover, Yutu-1. It was followed in 2019 by Chang’e-4, which became the first vehicle to visit the far side of the Moon and land the Yutu-2 rover on the surface.
A year later, it landed on Chang’e-5, which sent nearly four pounds of lunar regolith close to Earth. The feat made China the third country – after the United States and the Soviet Union – to complete the complex orbital choreography of collecting a sample from the Moon.
According to Yuqi Qian, a lunar geologist at the University of Hong Kong, the Chang’e-5 and Chang’e-6 maneuvers are both tests for China’s future crewed missions to the Moon, which, like the China’s Apollo missions, 1960s and 1970s, required landing and then launching humans from the lunar surface.
While aiming to send astronauts to the Moon, China’s long-term strategy brings scientific benefits to understanding the solar system.
The Chang’e-5 sample was younger than lunar material collected by the Americans or Soviets in the 1960s and 1970s. It is made mostly of basalts or cooled lava from ancient volcanic eruptions.
Two Chinese-led research teams concluded that the basalts were about two billion years old, suggesting that volcanic activity on the Moon extended at least a billion years beyond the period inferred from American Apollo and Soviet Luna samples.
Other studies of this material ruled out theories that the Moon’s interior had warmed enough to generate volcanic activity. A research group found that the amounts of radioactive elements inside the Moon, which could decay and produce heat, were not high enough to cause the flares. Another result ruled out water in the mantle as a potential source of interior melt that led to volcanism.
Chang’e-6 was launched on May 3 with even greater scientific ambitions: to bring back material from the far side of the Moon. The visible side of the Moon is dominated by large, dark plains where ancient lava once flowed. But the other side has fewer of these plains. It also has more craters and a thicker crust.
And because this half never faces Earth, it is impossible to communicate directly with landers on the far side of the Moon, making it difficult to reach. China’s space agency relied on two satellites it had previously launched into orbit around the Moon, Queqiao and Queqiao-2, to stay in contact with Chang’e-6 during its visit.
The spacecraft used the same technique as Chang’e-5 to reach the Moon and then return its sample to Earth.
He then hid the material. The mission deployed a miniature rover that took a photo of the lander with a small Chinese flag raised. Then, on June 3, a rocket returned the sample canister to lunar orbit. The materials then returned to a spacecraft on June 6 that remained in orbit and was ready to begin the journey back to Earth.
On Tuesday, the sample container re-entered Earth’s atmosphere, then parachuted to the surface of the Siziwang Banner region of Inner Mongolia, where ground teams worked to recover it.
When scientists take possession of the soils on the far side of the Moon, they will compare the composition of the newly recovered basalts with those on the near side of the Moon. This could help them deduce how the Moon’s volcanic activity caused its two halves to evolve differently.
The mission team will also search for material from surrounding regions, carried far from its original sites by impacts with comets and asteroids. If strong enough, these collisions could have excavated material from the Moon’s lower crust and upper mantle, Dr. Qian said. This could lead to information about the structure and composition of the lunar interior.
The molten rock resulting from these impacts could also provide clues to the age of the South Pole-Aitken basin and the era in which it formed, during which scientists believe a barrage of asteroids and of comets bombarded the inner solar system.
This period “totally changed the geological history of the Moon,” Dr. Qian said, and was also “a critical period for the evolution of the Earth.”
Clive Neal, a planetary geologist at the University of Notre Dame, called the goals ambitious, but he looks forward to the discoveries that follow the sample’s return. Referring to China’s string of lunar successes so far, “it’s excellent,” he said. “More power to them.”
However, tense political relations will make it difficult for American scientists to collaborate with Chinese researchers on the study of samples from the dark side.
The Wolf Amendment, signed into law in 2011, prohibits NASA from using federal funds for bilateral cooperation with the Chinese government. Federal authorities recently granted an exemption to the space agency, which allowed NASA-funded researchers to request access to the nearby sample recovered by Chang’e-5. But another bill passed by the U.S. House of Representatives in June would prohibit universities with research ties to Chinese institutions from receiving funding from the U.S. Department of Defense.
Looking ahead, China has its eyes on the lunar south pole, where Chang’e-7 and 8 will explore the environment and search for water and other resources. It hopes to send crewed missions to the Moon by 2030. Ultimately, China plans to build an international base at the South Pole.
NASA’s Artemis campaign is also targeting the lunar south pole. Bill Nelson, the space agency’s administrator, has previously called the parallel programs a race between the United States and China.
Many scientists reject this formulation. Resources needed to study the Moon plummeted after American astronauts beat the Soviets to the lunar surface in 1969, Dr. Neal said. “I don’t like international space races because they are not sustainable,” he said. “A race must be won. Once you earn it, so what?
He added: “I think it’s important to look at space as something that can bring us together rather than drive us apart. »
Several countries provided payloads that flew with the Chang’e-6 mission, including France and Pakistan. Chinese researchers considered this a good sign for the future.
“Lunar exploration is a common effort for all humanity,” said Dr. Xiao, adding that he hopes for increased international collaboration, “especially among major space nations like China and the United States.”