Lunar probe has transferred samples for return trip to Earth

Lunar samples collected from the moon's far side by China's Chang'e 6 mission have been delivered to their final carrier, which will later bring them to Earth, according to the China National Space Administration.

After flying in a lunar orbit for about 56 hours, the sample-loaded ascender of the Chang'e 6 probe docked with the orbiter-reentry capsule combination at 2:48 pm on Thursday and then transferred a sealed container holding the precious lunar samples to the reentry capsule, the administration said.

The operation was the second automated rendezvous and docking of any spacecraft in lunar orbit. The first was made during the Chang'e 5 mission in December 2020.

The administration said that before the docking, the ascender carried out four orbital adjustment maneuvers.

Next, the ascender will depart from the orbiter-reentry capsule combination, which will then continue orbiting the moon until ground control gives it the order to leave lunar orbit and head back to Earth.

After arriving in Earth orbit, the orbiter and reentry capsule will eventually separate, and the reentry capsule will conduct a series of complicated maneuvers to return to a preset landing site in North China's Inner Mongolia autonomous region in late June.

As one of the world's most notable space missions this year, the Chang'e 6 is an unprecedented endeavor aimed at retrieving samples from the lunar far side for scientific studies.

So far, all of the lunar substances on Earth were collected from the near side of the moon through the United States' six Apollo manned landings, the former Soviet Union's three Luna robotic missions and China's Chang'e 5 unmanned mission.

The landscapes and physical characteristics of the far side, which permanently faces away from Earth, are very different from those of the near side, which is visible from Earth, according to scientists.

Analyzing the samples will help to better understand the origins of the moon and the solar system, they said.

The 8.35-metric-ton Chang'e 6 spacecraft, consisting of an orbiter, a lander, an ascender and a reentry capsule, was launched by a Long March 5 heavy-lift carrier rocket on May 3 from the Wenchang Space Launch Center in Hainan province. It entered lunar orbit on May 8.

After a host of sophisticated steps, the lander touched down at the South Pole-Aitken Basin, one of the largest known impact craters in the solar system, on Sunday morning.

During the 49-hour surface operation, which lasted from Sunday morning to Tuesday morning, a mechanical arm and a drill operated to collect surface and underground materials, which were then placed in a special container on the ascender. Meanwhile, several scientific apparatus were activated to conduct survey and analysis assignments.

After the tasks were completed, the ascender lifted off from the lunar surface and reached lunar orbit on Tuesday morning.

Wang Yanan, chief editor of Aerospace Knowledge magazine, said the successful docking and sample transfer marked another step closer to the full success of the Chang'e 6 adventure.

"Robotic rendezvous and docking between spacecraft require cutting-edge technologies, excellent planning and exceptionally high precision," he said. "Before Chang'e 5, all rendezvous and docking operations between two spacecraft components in lunar orbit took place during the Apollo missions, and those were monitored and controlled by astronauts with support from ground controllers."