WashU Expert: China probe returns with ‘treasure trove’ of moon rocks

A graphic simulation shows the orbiter and returner combination of China's Chang'e-5 probe after its separation from the ascender. (Image: CNSA)

The Chinese space agency announced Dec. 16 the return of a lunar probe bringing back the first fresh samples of rock and debris from the moon in more than 40 years.

Bradley Jolliff

Bradley L. Jolliff, the Scott Rudolph Professor of Earth and Planetary Sciences in Arts & Sciences at Washington University in St. Louis and director of the McDonnell Center for the Space Sciences, said that the Chang’e-5 lunar probe landed in a scientifically very important location on the moon.

“The samples collected and returned to Earth by Chang’e-5 are of one of the youngest volcanic surfaces on the moon,” Jolliff said of the probe that returned to Earth around 2 a.m. Beijing time Dec. 17 (noon Central Dec. 16). “Of course, ‘young’ is relative. If the impact-crater chronology is correct, the samples will be between 1 and 2 billion years old, and determining the exact age will provide critical information for a part of the lunar chronology that is now missing.

“All of the volcanic rocks collected by Apollo were older than 3 billion years. And all of the young impact craters whose ages have been determined from the analysis of samples are younger than 1 billion years. So the Chang’e-5 samples will fill a critical gap.”

The samples, which were collected in a location known as northwestern Oceanus Procellarum, may also help address other big big science questions, such as how the moon remained volcanically active for so long.

“Also, because of the impact process, which is so effective at distributing material across the lunar surface, the returned samples may contain bits and pieces of debris tossed in by the even younger (200-300 million years old) Aristarchus impact crater,” Jolliff noted. “That material would contain another important age determination for the cratering chronology as well as samples of rare silicic volcanism on the moon.

“These samples will be a treasure trove!”

Automated sample return from the moon is a tremendous technological feat by the China National Space Administration (CNSA), requiring many different spacecraft elements and involving tremendous risk.

But there are important advantages for future manned space exploration at stake.

“The moon has critical resources for use in space, namely hydrogen and oxygen,” Jolliff said. “While water ice may be abundant at the poles, H and O are readily available everywhere on the moon, but likely concentrated and easy to harvest in the Aristarchus pyroclastic deposit to the south of the Chang’e-5 landing site and in the ilmenite-rich basalts at the landing site itself.

“These materials can be further evaluated for their resource potential,” Jolliff added. “And having this sample-return capability means that other resource-rich parts of the moon are now accessible to CNSA by automated sample return.”