China develops materials to build highways on the Moon

The team at Beihang University improved old materials and combined them with 3D printing technology to build roads on the Moon in the future.

Chinese scientists are developing and testing technology to build highways on the Moon, SCMP reported on May 13. The new study was published in the China Journal of Highway and Transport.

China's Jade Rabbit 2 robot in the photo taken from the Chang'e 4 ship.

"I often dream of building a road on the Moon," said Zhou Siqi, lead author of the study and a PhD student at Beihang University's school of traffic science and engineering. She also said that, despite using complex technologies, the scene at the construction site can be quite simple with the robot using one hand to shovel the Moon dust and the other to stack bricks.

Under the guidance of Professor Li Feng, Zhou and colleagues looked at geopolymer materials discovered in the 1950s to solve the problem of building infrastructure on the Moon.

Soviet scientist Viktor Glukovsky accidentally discovered this material - originally called "earth cement" - in a physicochemical reaction that turns soft rock powder into a hard, ceramic-like material. Unlike conventional cement, which needs to be combined with a large amount of water, geopolymer only needs a small amount to promote the reaction between rock powder and sodium hydroxide - a cheap chemical used to flush dirty pipes.

As the bricks harden, the chemical process releases all the water molecules to collect and reuse in the next stage of the manufacturing cycle. As a result, it became possible to build roads between stations on the Moon.

Researchers around the world have made many proposals over the past decades for how to build infrastructure on the Moon, including melting lunar dust at extremely high temperatures and collecting sulfur from the soil layer. surface for making cement.

But some space scientists think the problem is too difficult to solve. Instead, they argue that more practical alternatives should be found, such as building mobile stations, stone transport systems, powerful all-terrain vehicles, even cable cars.

Geopolymer tiles made with 3D printing technology could be used to build roads on the Moon.

Zhou's team combined old materials with modern 3D printing technology and experimented with simulated lunar soil to find the right recipe for a lunar highway. This road needs to provide a fast, safe and dust-free travel experience. Fine Moon dust not only causes wheels to slip, but it can also get in the way of solar panels and damage equipment.

The Moon vehicle on the Apollo mission only reached speeds of 18km/h on relatively flat terrain. An unmanned vehicle, such as China's Jade Rabbit, must crawl at less than 200m per hour to avoid pits or rocks.

The team at Beihang University said that preliminary research results suggest that road construction on the Moon may be possible. They also encountered some difficulties, for example adding too much water made the finished product too soft, while lack of water made it sticky and jammed the printer. They also found that producing geopolymer at different times of the day also affected quality due to temperature differences.

It takes about 20 minutes to produce a brick in the lab using a desktop-sized 3D printer, Zhou said, but the process is much faster with a full-size printer. A well-designed hollow structure will also help save materials and increase productivity.

According to the team of experts, sodium hydroxide makes up less than 1% of the materials needed. It can be obtained from Earth or produced on the Moon, where sodium is abundant. The team also found that adding a third of a gram of water to every gram of lunar soil at 80 degrees Celsius would make the bricks strong enough to build roads without clogging the printer.

However, Zhou's desire to build a road on the Moon faces a major challenge. "We don't know for sure if there's water on the Moon," she said.

Remote sensing data and computer models have shown that ice exists at the bottom of some of the dark wormholes near the Moon's south pole. Over the next few years, China plans to conduct a number of robotic expeditions in the area in search of direct evidence.

China has been working with Russia to build an international research station on the Moon for about a decade, but the first step will be to determine water supplies. A space nuclear reactor capable of producing one megawatt of electricity is also being developed to provide an abundant and stable source of energy for lunar settlements.