Scientists extracted water and oxygen from moon dust using sunlight. Could it work on the lunar surface?

科学家利用阳光从月球尘埃中提取水和氧气。它能在月球表面工作吗？

Soil excavated from the moon could be used to produce oxygen and methane, which could be used by lunar settlers for breathing and for rocket fuel.

从月球上挖掘出来的土壤可以用来制造氧气和甲烷，这些氧气和甲烷可以被月球定居者用来呼吸和火箭燃料。

This is the conclusion of a team of scientists from China who have found a one-step method of doing all this. Whether it is economically viable, however, is up for debate.

这是一个来自中国的科学家团队的结论，他们找到了一种一步到位的方法来完成这一切。然而，它在经济上是否可行还有待商榷。

But the Chinese team thinks that it is. "The biggest surprise for us was the tangible success of this integrated approach," said team-member Lu Wang, who is a chemist from the Chinese University of Hong Kong, in a statement. "The one-step integration of lunar water extraction and photothermal carbon dioxide catalysis could enhance energy utilization efficiency and decrease the cost and complexity of infrastructure development."

但中国队认为是。“对我们来说，最大的惊喜是这种综合方法取得了切实的成功，”团队成员、香港中文大学化学家王陆在一份声明中说。“月球水提取和光热二氧化碳催化的一步集成可以提高能源利用效率并降低基础设施开发的成本和复杂性。”

They point out that studies have shown that transporting supplies from Earth to any future moon base would be expensive because the greater the mass of cargo, the harder a rocket has to work to launch into space. Studies have indicated that it would cost $83,000 to transport just one gallon of water from Earth to the moon, and yet each astronaut would be expected to drink 4 gallons of water per day.

他们指出，研究表明，将物资从地球运送到任何未来的月球基地都将是昂贵的，因为货物的质量越大，火箭发射到太空就越困难。研究表明，从地球运送一加仑水到月球需要83,000美元，然而每个宇航员每天要喝4加仑水。

Fortunately, the moon has plentiful water, although it is not automatically apparent. Brought to the moon by impacts of comets, asteroids and micrometeoroids, and even by the solar wind, water lurks in permanently shadowed craters at the lunar poles, trapped within minerals such as ilmenite.

幸运的是，月球有丰富的水，尽管它不会自动显现。彗星、小行星和微流星体的撞击，甚至太阳风带到月球上，水潜伏在月球两极永久阴影的陨石坑中，被困在钛铁矿等矿物中。

Extracting the water for drinking is relatively easy and there are numerous technologies that describe how this can be done, including heating the regolith by focusing sunlight onto it. However, the Chinese team has been able to take this one step further.

提取饮用水相对容易，有许多技术描述了如何做到这一点，包括通过将阳光聚焦在风化层上来加热风化层。不过，中国队已经能够在这方面更进一步。

"What's novel here is the use of lunar soil as a catalyst to crack carbon dioxide molecules and combine them with extracted water to produce methane," Philip Metzger, a planetary physicist from the University of Central Florida, told Space.com. Metzger was not involved in the new research, but he is the co-founder of the NASA Kennedy Space Center's 'Swamp Works', a research lab for designing technologies for construction, manufacturing and mining on planetary (and lunar) surfaces.

中佛罗里达大学的行星物理学家菲利普·梅茨格(Philip Metzger)告诉Space.com：“这里的新颖之处在于使用月球土壤作为催化剂来裂解二氧化碳分子，并将它们与提取的水结合以产生甲烷。”梅茨格没有参与这项新研究，但他是美国宇航局肯尼迪航天中心“沼泽工程”的联合创始人，这是一个研究实验室，旨在设计行星（和月球）表面的建筑、制造和采矿技术。

Methane would be more desirable than liquid hydrogen as a potential rocket fuel because it is easier to keep stable, thereby requiring less machinery and less cost to keep on the moon. Liquid methane, when mixed with oxygen as an oxidizer, is a potent rocket fuel. Many commercial companies such as China's Landspace are already launching methane-powered rockets.

甲烷比液氢更适合作为潜在的火箭燃料，因为它更容易保持稳定，从而在月球上保持所需的机械和成本更低。液态甲烷当与氧气混合作为氧化剂时，是一种有效的火箭燃料。中国国土空间等许多商业公司已经在发射甲烷动力火箭。

The water-bearing ilmenite is also a useful catalyst for reacting the water with carbon dioxide to produce oxygen and methane, and the Chinese team have developed a one-step process for doing so. First, they heat the regolith to 392 degrees Fahrenheit (200 degrees Celsius) by focusing sunlight to release the water inside. Then, carbon dioxide such as that which could be breathed out by astronauts is added to the mix, causing the ilmenite to catalyze the reaction between the extracted water and the carbon dioxide. Researchers tested this process, known as photothermal catalysis, in the laboratory using a simulant based on samples of lunar regolith returned to Earth by China's Chang'e 5 mission (the lunar samples are far too previous to destroy in such experiments, which is why a simulant is used instead).

含水钛铁矿也是水与二氧化碳反应产生氧气和甲烷的有用催化剂，中国团队开发了一种一步法工艺。首先，他们通过聚焦阳光将风化层加热到392华氏度（200摄氏度）以释放其中的水分。然后，将宇航员呼出的二氧化碳添加到混合物中，使钛铁矿催化提取的水和二氧化碳之间的反应。研究人员在实验室中测试了这一被称为光热催化的过程，使用了一种基于中国嫦娥五号任务返回地球的月球风化层样本的模拟物（月球样本太早了，无法在此类实验中销毁，这就是为什么使用模拟物来代替）。

While previous technologies have also been able to accomplish this, they required more steps and more machinery, and used a catalyst that would have to be transported up from Earth. This, the research team believe, makes their process more efficient and less expensive than the alternatives.

虽然以前的技术也能够实现这一点，但它们需要更多的步骤和更多的机器，并且使用了必须从地球上运输的催化剂。研究小组认为，这使得他们的过程比替代方案更有效、更便宜。

However, Metzger is not wholly confident that it will work. For one thing, lunar regolith is a proficient thermal insulator, so heating a sample all the way through would not be easy.

然而，梅茨格并不完全相信它会起作用。首先，月球风化层是一种熟练的绝缘体，因此完全加热样品并不容易。

"The heat does not spread effectively deeper into the soil, and this greatly reduces the amount of water that can be produced in a given time," Metzger said. One option could be to 'tumble' the regolith, turning it over repeatedly so that the heat is more evenly applied, but this slows the extraction of water and increases the mechanical complexity of the process. In an environment where lunar dust gets into every nook and cranny, and where temperature fluctuations between night and day can be as great as 482 degrees Fahrenheit (250 Celsius), the risk of breakdown only increases as more moving parts enter the equation.

“热量不能有效地扩散到土壤深处，这大大减少了在给定时间内可以产生的水量，”梅茨格说。一种选择是“翻滚”风化层，反复翻转，以便更均匀地施加热量，但这会减慢水的提取速度并增加该过程的机械复杂性。在月球尘埃进入每个角落和缝隙的环境中，昼夜温度波动高达482华氏度（250摄氏度），随着更多的运动部件进入等式，故障的风险只会增加。

"It may be doable, but more maturation of the technology is needed to show that it is actually competitive," said Metzger.

“这可能是可行的，但需要技术更加成熟才能表明它实际上具有竞争力，”梅茨格说。

There's also a problem with the application of carbon dioxide, something recognized by both the Chinese team and Metzger. Specifically, there's a question mark over whether astronauts could produce enough carbon dioxide through their normal exhalation. Metzger calculates that astronauts could only provide a tenth of the carbon dioxide required. Alternatively, carbon dioxide could be shuttled up from Earth, but this would rather defeat the purpose of the proposed technique, which was to develop a lot-cost means of obtaining water, oxygen and methane with resources largely already available on the moon.

二氧化碳的应用也存在问题，这是中国队和梅茨格都认识到的。具体来说，宇航员是否能通过正常呼气产生足够的二氧化碳是一个问号。梅茨格计算出，宇航员只能提供所需二氧化碳的十分之一。或者，二氧化碳可以从地球上运送上来，但这将违背拟议技术的目的，即开发一种成本高昂的方法，利用月球上已经有的资源获取水、氧气和甲烷。

However, in the long-run, perhaps shipping some materials up from Earth will be beneficial. Metzger points out a similar experiment that used an exotic granular catalyst – nickel-on-kieselguhr (kieselguhr is a kind of sedimentary rock) – rather than lunar regolith. Metzger suspects that a material specifically designed to be a catalyst, such as nickel-on-kieselguhr, would be more efficient than lunar regolith. Plus, although it would be expensive to transport from Earth, the nickel-on-kieselguhr can be re-used so you would only need to transport it to the moon once. In a cost-benefit analysis, in the long term it might be more efficient to do this instead.

然而，从长远来看，也许从地球上运送一些材料会是有益的。梅茨格指出了一个类似的实验，该实验使用了一种奇特的颗粒催化剂——硅藻土上的镍（硅藻土是一种沉积岩）——而不是月球风化层。梅茨格怀疑，一种专门设计为催化剂的材料，如硅藻土上的镍，会比月球风化层更有效。此外，虽然从地球运输会很昂贵，但硅藻土上的镍可以重复使用，所以你只需要将它运输到月球一次。在成本效益分析中，从长远来看，这样做可能更有效。

Regardless, the research team has convincingly shown that using lunar regolith as a catalyst to produce fuel and water works. The next step is to show that the technology can be scaled up to sustain a base on the moon more efficiently than other techniques, and that it can operate in lunar conditions where the gravity is weaker, the temperature swings to large extremes, and there is intense radiation from space.

无论如何，研究小组已经令人信服地表明，使用月球风化层作为催化剂来生产燃料和水是可行的。下一步是证明该技术可以扩大规模，比其他技术更有效地维持月球基地，并且它可以在重力较弱、温度波动较大且存在强烈辐射的月球条件下运行来自太空。

"I think these are highly interesting results and there may be additional applications to use lunar soil as a photocatalyst," said Metzger. "More work will be needed to show whether this concept can be economically competitive. I am skeptical, but all good ideas have their detractors and you can never really know until somebody does the work to prove it."

“我认为这些是非常有趣的结果，使用月球土壤作为光催化剂可能还有其他应用，”梅茨格说。“需要更多的工作来证明这个概念是否具有经济竞争力。我对此表示怀疑，但所有好的想法都有批评者，除非有人努力证明它，否则你永远无法真正知道。”

There is certainly no immediate rush for the technology. With NASA's Artemis III mission, which aims to finally return astronauts to the surface of the moon in 2027 at the earliest, and funding made available for Artemis IV and V at some indeterminate time in the future, we're not yet in a position to build a permanent lunar base.

当然，人们不会立即急于获得这项技术。随着美国宇航局的阿耳忒弥斯三号任务（目标是最早在2027年将宇航员送回月球表面）以及在未来某个不确定的时间为阿耳忒弥斯四号和五号提供资金，我们还没有能力建造一个永久的月球基地。

However, the Artemis missions are the perfect opportunity to trial some of these technologies and will be greatly important for showing whether we really can live on the moon or not.

然而，阿耳忒弥斯任务是试验其中一些技术的绝佳机会，对于展示我们是否真的可以在月球上生活非常重要。

The research was published on July 16 in the journal Joule.

这项研究发表在7月16日的《焦耳》杂志上。