In the two-way race between the United States and China to return humans to the Moon, the lunar south pole is widely considered the most popular place to land. The region is relatively rich in resources, dotted with dark craters that harbor water ice and are exposed almost constantly to sunlight around their respective edges – both desirable features for lunar bases. The South Pole-Aitken basin, the largest and oldest impact structure on the Moon, dominates the region. Located on the far side of the Moon, it is protected from terrestrial radio communications, which makes it an ideal site For ultrasensitive astronomy observations.
But this promise comes with considerable perils: Compared to other landing sites, the south polar region is more difficult to reach and its craters are more dangerous. And without a relay in orbit around the moonthe hidden side is cut off from communication with Earth.
However, the United States chose nine candidate sites there for a landing attempt planned for 2028 within the framework of NASA’s Artemis program. But a new paper published yesterday in Natural astronomy reinforces the arguments that China defends an easier initial crewed landing site the one closer to the equator and on the side closest to the Moon, with a plan to put boots on the surface by 2030.
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Using data from U.S., Chinese, Indian and Japanese lunar missions, as well as archival observations from the Arecibo ground-based radio telescope, the authors argue that Rimae Bode, a relatively flat region north of the equator on the Earth-facing side of the Moon, is a prime location for China’s first moonwalking astronauts.
“Rimae Bode is a high-priority ‘sweet spot,'” says Jun Huang, a planetary geologist at China Wuhan University of Geosciences and co-lead author of the new study. “Think of it as prime lunar real estate: its location near the equator provides much flatter and safer terrain for landing, as well as constant sunlight for energy. [during the lunar day] and a direct line of sight to Earth for easy communication.
Jim Head, a professor emeritus at Brown University who helped select landing sites for NASA’s Apollo moon missions and trained astronauts in geology field work, agrees that the region is one of the best candidates. He regularly collaborates with Chinese scientists who are developing that country’s lunar exploration program but was not involved in this study.
“Rimae Bode would be on my ‘short list of human lunar exploration landing sites,'” Head said, adding that the region was considered an Apollo mission destination. “More than 50 years after Apollo, the importance of Rimae Bode’s multiple essential scientific objectives remains! »
Rimae Bode is located between Mare Vaporum, a basin filled with dark, cooled lava, and the lighter-colored, older, and more rugged central lunar highlands. “Scientifically, it’s like an ‘all-you-can-eat geological buffet’ that the South Pole cannot offer,” says Huang.
He and his team identify five features of interest: a large, dark layer of glassy volcanic ash; a basalt plain called Sinus Aestuum; two basalt terrains of Rimae Bode proper, one of which is dotted with volcanic trenches called rills, and finally the surrounding highlands.
The article describes the complex geology of the region: the authors analyze its mineralogy and topography, as well as the distribution of craters across the landscape. The ash layer, for example, likely emerged from the lunar mantle billions of years ago, providing a unique window into lunar history.
Tiny glass beads in the ashes are Rimae Bode’s “crown jewels,” Huang says: These “time capsules” could help reveal the moon’s mysterious interior. “By studying them, we can finally understand what the Moon is really made of, deep within ourselves, and piece together the full story of how its volcanic activity evolved over time, transforming the Moon from a fiery, active world into the quiet neighbor we see today,” he says.
Orbital observations suggest that the ash could also “contain significant water resources,” says Clive Neal, a planetary scientist at the University of Notre Dame who was not involved in the new study. Water is essential for survival on a lunar mission and for making rocket fuel. “And none of these deposits have been sampled before – another [potential] first for China.
The water-rich minerals in the ash could mean the lunar mantle is wetter than scientists thought, Neal says. “But most important in this age of human exploration is resource potential. Could we have an easier-to-access human outpost at the equator rather than at the poles?”
Based on their analysis, Huang and his co-authors propose four potential landing sites within Rimae Bode; they also chart paths that Chinese astronauts could use to explore and study the surrounding terrain more safely. Huang’s favorite of the four is Landing Site 2 (LS2), a flat area north of Rimae Bode that is within a few kilometers of several scientific targets. “LS2 poses a triple scientific threat,” he says, giving astronauts access to volcanic glass beads, a massive lunar trench and “unique high-thorium materials that are critical to understanding the chemical evolution of the Moon.”
Obtaining samples from Rimae Bode would allow comparisons with lunar material collected in other regions, Head says. The Apollo missions brought back collectively nearly 400 kilograms of material recovered from mid-to-low latitudes on the near side of the Moon, while China Chang’e 5 And Chang’e 6 robotic missions returned smaller samples from the near and far sides of the moon, respectively.
If China makes a first crewed landing near the equator, that doesn’t mean its astronauts won’t later explore the lunar south pole or other harder-to-reach places, Head says. Launch of China’s Chang’e 7 spacecraft later this yearshould land at the South Pole, on the edge of Shackleton Craterwhere he will look for water ice. And those of 2029 Mission Chang’e 8 is also designed to target the South Pole as a precursor to China’s crewed base, called the International Lunar Research Stationwhich is being planned in partnership with Russia and other countries. The American Apollo missions followed a similar progression, progressing steadily in difficulty and success, Head explains: “The Chinese are following a safer, sequential path, as was the case with Apollo.” »
There is of course a lot of work to be done before anyone heads to Rimae Bode. Huang and his co-authors are particularly eager to higher resolution images of the region to better characterize its geology and assess how well astronauts could navigate its terrain – which could come from a new lunar mapping satellite that China announcement last year.
