Chang’e-6 Retrieves Soil Samples from the Far Side of the Moon

On June 2, China’s Chang’e-6 spacecraft landed on the Moon’s far side for a second time, and was able, for the first time, to collect rock samples from the oldest lunar basin to bring back to Earth (cf. SAS 19/24). After successfully touching down in the northeastern part of the South Pole-Aitken basin, which was created more than four billion years ago, and going through initial checks, the Chang’e-6 lander began using its robotic arm to drill and scoop up materials from the lunar surface weighing up to 2 kg. Once returned to Earth, they will become the first samples ever retrieved from the Moon’s mysterious far side, given that name because it always faces away from us.

The 8.35-ton spacecraft – which consists of a lander, ascender, orbiter, and return capsule – entered lunar orbit about four days after its May 3 launch, and had been circling the Moon since then, looking for the best spot and time to land. On May 30, the lander and ascender separated from the orbiter and return capsule. The lander then fired its 7,500-Newton-thrust engine to slow down and began to descend from about 15 km above the lunar surface.

In this process, the cameras on the lander snapped photos of the landing area and transmitted them to computers on the lander to identify possible hazards on the surface, such as large rocks, so that the craft could maneuver to avoid them.

At about 100 meters above the lunar surface, the combined vehicle suspended its descent and hovered for a moment to conduct accurate detection of smaller obstacles and determine the final landing spot before continuing to descend at a slower, steady speed.

As the craft came to just several meters above the surface, it shut off its engine and touched down on the lunar surface, making China now the only country to have soft landed on the far side for a second time. The soil samples were gathered over the next two days, after which the Chang’e-6 mission began the journey back on June 4. It is expected to reach the Earth around June 25.

The mission has received relatively little attention from the Western press, given the abundance of new knowledge it’s expected to produce. Indeed, the material retrieved will give researchers the unique opportunity to examine matter that has been continually bombarded from the surrounding cosmos, matter that should help us understand the origins of the solar system, and perhaps give us a greater clue to the development of the Earth itself.