Exploration

Chang’e 6 Brings Back Samples from the Far Side of the Moon

Published on 25 June 2024

The Chinese Chang'e 6 probe landed on the far side of the Moon on June 1. It took a sample and the upper stage took off again. On June 25, the capsule, loaded with 2 kg of samples, returned to Earth.

It’s done! On June 25, the box bringing back 2 kg of samples from the far side of the Moon landed on Earth. After having succeeded for the second time in landing on that side of the Moon, China demonstrated its capabilities in exploring our satellite. Remember that Chang’e 6 took off on May 3.

The Chang’e 6 capsule loaded with the precious samples landed in the Chinese Autonomous Region of Inner Mongolia.

The Return to Earth

The Capsule, Loaded with Samples, Successfully Re-Entered the Atmosphere

It touched down at 8:07 a.m. Paris time. Before that, the Chang’e-6 capsule, weighing about 300 kilos, separated from the mission’s service module 5,000 kilometres from Earth, completing a 53-day mission. The capsule began its return to the atmosphere over the Atlantic Ocean around 7:41 a.m. to decelerate, before landing in the vast prairies of the Siziwang Banner, a region of the Chinese Autonomous Territory of Inner Mongolia. The capsule should contain nearly 2 kg of samples from the far face of the Moon taken by Chang’e 6’s arm.

Better Understand the Composition of the Moon

Samples of rocks and regolith from the Apollo crater, located in the southern part of the far side of the Moon. “The South Polar Aitken (the region where Chang’e 6 landed) is an impact basin, which, in the early history of the Moon, made it possible to excavate rocks from the mantle,” explained Pierre-Yves Meslin, the head of the French Dorn instrument at IRAP, who participated in the Chang’e 6 mission, before take-off. “By going to collect samples in this region, we hope to be able to collect both fragments of rock from the highlands and the rocks of the mantle.” The study of these samples should, therefore, allow us to know more about the composition of this part of the Moon.

Images of Surface Operations

Successful Sampling and Activation of DORN

On June 2, the Chang’e 6 mission lander successfully arrived in the Apollo crater on the far side of the Moon (see below). The Chinese space agency CNSA has since confirmed the success of surface operations. First and foremost was what the CNSA called in a statement “intelligent rapid sampling“. The video opposite summarises this process carried out with a robotic arm which takes the samples and then deposits them in the upper section of the lander. The use of a drill capable of going up to 2 m deep in the ground was part of the automatic procedures provided. The commissioning and proper operation of the French DORN instrument was also highlighted.

The Chang’e 6 lander photographed by a small rover which moved away from it. Inset, the Chinese flag deployed on the machine shortly after arrival.© CNSA

Chang’e 6 Photographed by a Small Rover

Before the departure of this mission, several observers of Chinese space activities suggested that the lander could well be equipped with a small rover. Photos of it during its preparation on Earth had even circulated on the web. The mobile robot, after moving away, took a picture of the Chinese lander on the surface of the dark side, an image that will certainly illustrate China’s new success in the coming years. Still in symbolic mode, the lander did indeed display a small flag of the country.

The Return of the Samples Has Begun

As was the case with the previous Chinese lunar sample return mission (Chang’e 5 in 2020, but from the visible side), all surface operations took place in two days. On June 4 at 7:38 a.m. (Beijing time, 11:38 p.m. on June 3 in Universal Time), the upper section of the lander took off, taking the samples. The video opposite shows this departure filmed by a camera installed on the lower part of the lander, which remained on the moon.

A delicate stage was therefore approaching, that of the
rendezvous around our natural satellite between the upper section which took
off and Chang’e 6’s ship (still in lunar orbit) which contains the capsule
that will be used to return the samples to Earth. After a mooring manoeuvre,
the samples were to be transferred there in a robotically. The arrival on Earth
of the capsule is scheduled for June 25.

The Chinese space agency CNSA indicated in a statement the success of the rendezvous and the transfer of the samples to the return capsule.

Panorama of the surface of the dark side within the Apollo crater where the Chang’e 6 lander landed.

2 kg of Samples and a French Instrument

While the moon landing was expected around midnight Universal Time on June 1 (2 a.m. on June 2 in French time) on the southern portion of the Apollo crater, the Chinese space agency CNSA (China National Space Administration) announced in a statement that its lander had landed at 10:23 p.m. Universal Time on June 1 (i.e. 6:23 a.m. Beijing time on June 2). As with previous Chinese arrivals on our natural satellite, the procedure was fully automatic.

The CNSA declared that the French DORN instrument designed at the IRAP in Toulouse (see our article for all the details) is “about to operate“. As part of international scientific cooperation, Chang’e 6 also brings to the Moon instruments provided by Italy and Sweden. These are respectively the INRRI (INstrument for landing-Roving laser Retroreflector Investigations) and the NILS (Negative Ions on Lunar Surface) laser retroreflector.

The CNSA indicates that this image of the dark side of the Moon was taken by Chang’e 6 during its landing phase.

Illustration of Chang’e 5 which automatically brought samples from the Moon in 2020. Chang’ 6 is similar.

First Return of Samples from the Far Side of the Moon

Within 48 hours of its arrival, Chang’e 6 will take samples of the lunar surface, the goal being to obtain 2 kg. The upper part of the craft will then take off and join the other section of the spacecraft in Moon orbit to place the precious harvest in a capsule that will begin a journey back to our planet. Its parachute landing is planned around June 25.

Several samples from the Moon have in the past been brought back to Earth by NASA’s Apollo missions and automatically by the Soviets and the Chinese (Chang’e 5 in 2020). On the other hand, Chang’e 6 will mark the first return of lunar samples from the far side.

This video posted on YouTube by the SciNews account is from the Chinese space agency CNSA. This video has been accelerated. Around 0:43, there is a pause in the descent. This is the usual procedure by which the on-board computer analyses the images from the camera to avoid any possible obstacles. We can also see the surface dust raised by the propulsion just before the moon landing (at 0:46).