Caves are one of the first shelters of mankind. Who knows what our distant ancestors were thinking by taking shelter there, gathering together and cooking meat over the fire, or perhaps drawing animals on the walls. Caves protected our ancient ancestors from natural conditions as well as from predators and rivals, at a time when our only technology was sticks, stones, furs and fire.

So, there is a poetic parallel between us and primitive people. We are revisiting the Moon, and just as caves housed our ancestors on Earth, lunar caves may house us.

On the Moon, astronauts will need protection from different dangers. They will have to fight with cosmic and solar radiation, meteors, extreme temperature fluctuations and even emissions. The Lunar Reconnaissance Orbiter (LRO) has found hundreds of lunar “hatch” sites where the roof of a lava tube has collapsed, creating a natural opening in the tube. It’s hard to say anything without research, but there may be lava tubes a few hundred meters in diameter on the Moon. That’s a lot of space to work with, and they could provide the shelter astronauts would need. The idea is to build a base inside the lunar lava tube, where astronauts would have additional protection against the thick rock ceiling above their heads.

China, like other countries before them, is currently considering this idea. Lunar lava caves may be too valuable a resource to ignore.

Lava pipes are also called pyroproducts. They were formed when the lava flowing on the lunar surface began to cool. The top of the flowing lava formed a solidified crust, but molten lava continued to flow beneath it and eventually flowed out, leaving an empty pipe. They are here on Earth too.

Scientists aren’t sure when volcanism on the moon ended. It may have happened about a billion years ago, but some evidence suggests little volcanism in the last 50 million years. In any case, these lava tubes are old and intact.

On the Moon, astronauts will have to deal with temperature fluctuations. Earth’s natural satellite is a world of extreme temperatures. One side of the Moon is in direct sunlight half the time, with surface temperatures reaching 127°C (260°F). The side engulfed in darkness drops to -173°C (-280°F). .) These drastic temperature changes make it difficult to work on the lunar surface and to design and manufacture equipment that can be effective over such a wide range. Lava tubes create a naturally stable temperature environment that cannot be found anywhere else on the Moon.

Radiation is also dangerous on the Moon’s surface. It may be 150 times stronger than the Earth’s surface. It’s deadly, but in lunar caves, astronauts will find shelter several feet above their heads. This is a thick enough barrier to provide effective protection.

The risk of collision and impact debris is much lower, but this must be taken into account. Apparently lava tubes protect against minor impacts.

Different groups of scientists from different countries and institutions have worked on the idea of ​​using lava tubes as shelters. At a recent conference in China, Zhang Chunfeng from the Shanghai Academy of Space Technology presented his research on the underground world of lava tubes. Chinese researchers conducted field studies to understand how to use Chinese lava tubes on the moon.

According to Zhang, there are enough similarities between lunar and terrestrial lava tubes that one is an analogue of the other. It starts with two types of entrances: vertical and inclined. Both worlds have both types.

Most of what we find on the Moon are pipes with vertical openings, but that may be due to our view from above. Openings where the ceiling collapses, causing a buildup of debris on the floor of the pipe directly below, are called skylights. Entry from these requires flight or some form of vertical climbing equipment.

Sloped entrances make getting in and out much easier. Although some debris will probably need to be cleared, rovers can easily enter them. According to Zhang, this is the best introduction to facilitate research. China favors lunar lava tubes in Mare Tranquillitatis (Sea of ​​Tranquility) and Mare Fecunditatis (Sea of ​​Fertility) for exploration.

China plans to build a robotic system that can explore caves like the one in Mare Tranquillitatis. The main probe will have wheels or legs and will be designed to adapt to difficult terrain and overcome obstacles. It will also carry a scientific payload.

Support vehicles can be detached from the main probe to perform further reconnaissance and assist with communications and “power support.” They can be varied so that the task can meet different challenges. These can include multi-legged crawling probes, rolling probes, and even jumping probes. These rovers will also carry scientific instruments to study lunar dust, radiation and the presence of water ice in tubes.

China is also planning a flying robot that could autonomously find its way through lava tubes using microwave and laser radar.

After successful exploration, China’s future plan is to establish a manned base. There will be a long-term underground research base in one of the lunar lava tubes, with a power backup and communications center at the entrance to the tube. The area will be landscaped and the base will contain both living and research facilities inside the tube.

China doesn’t have the enthusiasm for information sharing that an organization like NASA has, so details are harder to disclose. But there is no doubt that China’s space activities are currently on the rise; Many successful missions have been completed, some are still ongoing, and there are others planned for the future. In the spring of 2023, China announced that it planned to begin construction of a moon base by 2028, but it is unclear whether the announcement referred to a lava tube moon base. This appears to contradict the recent announcement that China plans to “put a man on the moon by 2030.”

But no matter when they start, China seems to agree with the idea. Ding Lieyun, a leading scientist at Huazhong University of Science and Technology, told China Science Daily: “After all, the construction of an extra-Earth settlement is important not only for all humanity’s pursuit of space exploration, but also for China’s strategic needs .as a space power This language almost exactly mirrors the language NASA uses when talking about the Artemis program.

Preparing for new moon missions and a possible base, Chinese researchers studied both Mare Tranquillitatis and Mare Fecunditatis. In 2022, a team of scientists published a study on the volcanic features of Mare Fecunditatis in a journal. Remote sensing.

Mare Fecunditatis is rich in volcanic features, including lava tubes. The 2022 document notes that no mission to the lunar surface has gone further than 40 km (25 mi), but this will change in the future. The researchers behind the study propose a five-year flight similar to NASA’s Mars rover missions. In five years, the Chinese rover was able to explore Mare Fecunditatis, covering 1,400 km (870 mi). By examining volcanic features such as lava tubes, domes and vents, they can gain a more comprehensive understanding of the moon’s regional geology. They can also choose a location for the moon base.

China is not the first to consider lava tubes as a foundation. The idea has been around for a long time. But soon China and other space countries will be able to discover them and seriously approach the creation of such a thing.

Space exploration and politics are intertwined, and more so in China than in other countries. The inner workings of both are sometimes hidden behind an opaque wall, and the details are not always readily available. It’s like people are afraid of saying the wrong thing. But China’s intentions are clear, and if history is any indication, they will go to the moon and build a base.

Perhaps some of the Chinese taikonauts who have finally taken shelter in these lunar caves will take a moment or two to think about our ancient ancestors and how the caves housed them. Perhaps one of them will be the first to put a mark on the wall of a lunar lava tube. Then one day, when humanity is extinct, future alien explorers may find these signs and ponder their meaning.