First ever rocks from the Moon’s far side have landed on Earth

The first rocks from the far side of the Moon have just landed safely on Earth and scientists can’t wait to study them.

China’s Chang’e-6 re-entry capsule, containing up to two kilograms of materials scooped and drilled from the Moon’s most ancient basin, touched down in the grasslands of Siziwang Banner in the Chinese northern autonomous region of Inner Mongolia at 2.07 p.m. Beijing time on Tuesday, according to the China National Space Administration (CNSA).

“The samples are going to be different from all previous rocks collected by the US, Soviet Union and China,” which came from the Moon’s near side, says Yang Wei, a geochemist at the Institute of Geology and Geophysics in Beijing. “We have very high expectations for them,” Yang says.

Chang’e-6 launched on 3 May and arrived at the Moon five days later, where it stayed in lunar orbit to prepare for landing. On 2 June, it touched down at a preselected site inside the South Pole–Aitken (SPA) basin, which is covered in dark-coloured cooled lava rocks known as basalt, and conducted intense sampling using a drill and a robotic arm for two days. The precious cargo then lifted off from the Moon, docked with the re-entry capsule in lunar orbit and headed towards Earth.

At about 1.20 p.m. Beijing time on Tuesday, the landing procedure kicked off. The capsule skipped off the atmosphere to reduce its speed, before diving down at 11.2 kilometres a second. A parachute was deployed to assist with the descent. A recovery team located the capsule shortly after it landed. Once the team has processed the capsule on site, it will be transported to Beijing, where it will be opened and the samples removed for scientific analysis and storage, says the CNSA.

Patrick Pinet, a lunar geologist at the Research Institute in Astrophysics and Planetology (IRAP) in Toulouse, France, watched the mission unfold in real time from a control room in Beijing. “I’ve seen an incredible technical efficiency and professional mastering of all these very complex steps along the way,” he says.

“China’s ability to carry out highly complex missions at lunar distance is robust,” says Jonathan McDowell, an astronomer at the Harvard–Smithsonian Center for Astrophysics in Cambridge, Massachusetts. The technologies to control a spacecraft and communicate with it, and to manoeuvre in lunar orbit, land, take off and rendezvous “will be important to have well in control for a human lunar mission in the near future”, he says.

Scientific priorities

Earlier this month, more than 200 scientists from Chinese universities and research institutes met in Beijing to discuss the scientific questions they hope to address by analysing the Chang’e-6 samples. Participants voted for three problems they considered the most important. The top question to explore is why the Moon’s two faces are so different, followed by what the composition of deeper lunar structures is and when the SPA basin formed.

International researchers are hoping to work on Chang’e-6 samples, too. Qing-zhu Yin, a geochemist at the University of California, Davis, wants to use them to work out the timing of the initiation and termination of the lunar magma ocean in the aftermath of the giant impact that formed the Moon.

International cooperation

Chang’e-6 carried four international instruments to the lunar orbit or surface. Among them was the European Space Agency’s Negative Ions at the Lunar Surface (NILS) detector and a French instrument called the Detection of Outgassing RadoN (DORN).

NILS detected negative ions on the Moon for the first time. Studying these particles will help scientists to understand the lunar surface environment and design robotic and crewed missions in the future. “A lot more work is needed before we could talk about the species and quantities of the ions,” says NILS project manager Neil Melville, who is based in The Hague, the Netherlands.

Pierre-Yves Meslin, a principal investigator on DORN at IRAP, says his team recorded 19 hours of good-quality data during the surface operations. “We are now working on the calibration and analysis of the scientific data, but we can already tell that the performance of the instrument has been met,” he says. “The Chinese and French members of the DORN team had very successful teamwork, and we received great support from the China National Space Administration and the Beijing Aerospace Flight Control Center, among others. We really felt part of the mission.”

Future missions

China is now developing its Chang’e-7 and Chang’e-8 missions, which are more complex and are scheduled to launch in 2026 and 2028, respectively. They will hunt for water ice near the lunar south pole and conduct other surveys and experiments. Water ice can be used to make oxygen and rocket fuels, and local supplies will be crucial for establishing a long-term human presence on the Moon.

The three missions are part of China’s larger lunar programme to establish a Moon base by the mid-2030s, says Namrata Goswami, a space-policy researcher at Arizona State University in Phoenix. “The ability of China to execute their space missions on time means it will realistically establish the first ever permanent presence on the Moon,” she says.