China Brings Samples From the Moon’s Far Side to Earth in First-Ever Feat

In a global first, the China National Space Administration (CNSA) has successfully retrieved rock and soil samples from the far side of the moon, a feat that will offer scientists an unprecedented opportunity to study the lesser-understood lunar face that is never visible from Earth.

The samples re-entered Earth’s atmosphere on Tuesday and landed via parachute in rural Inner Mongolia, an autonomous region in northern China. They were secured in a re-entry capsule that detached from a larger spacecraft, called Chang’e-6. The entire mission, the sixth leg of the Chinese space agency’s Chang’e project, lasted nearly two months and marked a milestone for lunar research.

“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 China University of Geosciences, tells the New York Times’ Katrina Miller. “This is a major event for scientists worldwide… a cause for celebration for all humanity.”

Launched on May 3, the Chang’e-6 spacecraft consisted of four modules: an ascender, an orbiter, a lunar lander and a return capsule. It reached lunar orbit five days later, where it remained for several weeks. On June 1, the lander successfully descended and touched down on the far side of the moon in its oldest and largest impact crater, known as the South Pole-Aitken basin.

This itself was no small feat: Directing the movement of a spacecraft on the far side of the moon is difficult, because the moon blocks radio signals from Earth. To get around this problem, CNSA engineers used two relay satellites, Queqiao and Queqiao-2, launched ahead of this mission, to communicate with the spacecraft.

Once on the moon, Chang’e-6 used a robotic arm’s scoop and drill to collect 4.4 pounds of lunar material from impact crater. Compared to the lunar face we can see, the far side of the moon has a thicker crust, fewer ancient lava plains called maria and a greater number of craters and debris from collisions.

“Recovering samples from the far side is tremendously exciting scientifically, as we only have very limited information on the geology there,” Martin Barstow, an astrophysicist at the University of Leicester in England, tells the Guardian’s Ian Sample. “It has been processed very differently to the side of the moon facing us, which has been extensively resurfaced by volcanic activity in the past, creating the maria from which most samples have been obtained.”

The collection of rocks launched from the lunar surface in the spacecraft’s ascender on June 3, then united with the orbiter days later. It began its Earth-bound journey on June 21, culminating in its arrival to China this week.

Scientists hope the newly secured material will offer clear evidence of the history of lunar asteroid impacts, which could, in turn, shed light on impacts to the early Earth. Most known basins on the moon formed from a barrage of space rocks some 3.9 billion years ago, during a period known as the Late Heavy Bombardment. It is likely, astronomers say, that asteroid showers that hit the moon also hit our home planet.

“This also has implications for understanding the origins of life on Earth,” the Planetary Society’s Jason Davis wrote earlier this year. “It’s possible that asteroids carried water and organic materials to Earth during the Late Heavy Bombardment. Understanding the timing and circumstances of this event is critical for unpacking our origin story.”

There is also a possibility, because the South Pole-Aitken basin is so deep, that the lunar mantle is exposed within it. If sediment from this layer were contained in the Chang’e-6 samples, scientists could uncover significant clues about the moon’s interior and origins.

“It’s a long shot, but it’s worth looking,” Ian Crawford, a planetary scientist at Birkbeck, University of London, tells the Guardian.

A number of countries—including the U.S., China and Russia—have been ramping up their planned exploration of, and human presence on, the lunar surface. The possibility for extraction of the moon’s untapped resources—and its location as a launching-off point toward Mars—remain incentives for nations to go to the moon.

Christian Thorsberg | READ MORE

Christian Thorsberg is an environmental writer and photographer from Chicago. His work, which often centers on freshwater issues, climate change and subsistence, has appeared in Circle of Blue, Sierra magazine, Discover magazine and Alaska Sporting Journal.