An article by Smriti Mallapaty on nature.com reminds me that we’re less than 2 weeks away from the launch of the Chang’e-5 lunar sample return mission. I am so excited to see this mission happen, because it’ll be the first time we’ve returned samples from the Moon since the Apollo and Luna missions. Why is that important? It has to do with what we learned from Apollo.
When I was editor of The Planetary Report I invited Long Xiao, who is one of China’s top scientists on the lunar program, to write a feature article on the Chang’e-4 and -5 missions. He explained the choice of the Mare Procellarum landing site for Chang’e-5:
“The region includes the Procellarum KREEP Terrane, a prominent geochemically anomalous area on the Moon. It is characterized by high concentrations of radiogenic heat-producing elements (such as thorium, uranium, and potassium) in a thin crust. It has also had much more recent volcanic activity than most of the rest of the Moon, the end of a long, complex geologic history. It may include some of the youngest material on the Moon. (For the Moon, “young” means younger than 3 billion years old.)…
“The Moon is the only cratered terrestrial world from which we have returned samples. Lunar geologists have matched cratering chronology with absolute ages measured from returned lunar samples, building a bridge between crater chronology and absolute ages. The chronology of the rest of the solar system is pinned to lunar chronology. So, Chang’e-5’s success will not only teach us more about the Moon; it will also assist in our understanding of the geological evolution of planetary bodies throughout the solar system.”
Chang’e-5 is going to drill as deep as 2 meters. This isn’t quite the deepest that’s ever been drilled; Russia’s Luna 24 got samples from deeper than that, from 223 centimeters below the surface. Still, it’s a nice depth and hopefully below some of the worst-weathered material.
Unfortunately, it will be difficult for U.S. scientists to get their hands on samples. The Wolf Amendmentprohibits them from using federal funding to collaborate with Chinese scientists, and China will likely not be feeling too generous with U.S. scientists who have other funding sources, given the lack of U.S. cooperation. But European scientists will be able to.
If Chang’e-5 is successful, the payoff for lunar science is going to be huge. Next year’s Lunar and Planetary Science Conference in March should be thrilling, though it might be a bit early for much in the way of science results. Since LPSC will be virtual, for the first time no Chinese speaker will have to get a visa to participate. It’s going to be a fun year for lunar science!
(Thanks so much to Barbara Cohen for answering my questions about lunar sample drilling!)
Graphic at the top of this article by Loren Roberts for The Planetary Society.