How to make oxygen on the moon

Sierra Space, a private aerospace company, is currently developing a groundbreaking device aimed at producing oxygen under conditions that closely resemble those found on the moon. A team of three engineers from Sierra Space is diligently working on this innovative machine, which is designed to operate in an environment similar to that of the lunar surface. Inside a large spherical chamber, the engineers meticulously examined their equipment. At the center of their efforts stood a sleek, metallic apparatus adorned with a multitude of colorful wires. This box-like device is what they aspire will eventually facilitate the generation of oxygen on the moon. Once the engineers completed their preparations, they initiated the experiment. The machine began to process small amounts of a dusty substance that serves as a substitute for moon dust. This material, known as regolith, is a combination of fine dust and sharp particles that mimics the chemical composition of actual lunar soil. Before long, the regolith was transformed into a viscous substance, heated to temperatures exceeding 1,650 degrees Celsius. With the introduction of specific reactants, oxygen-rich molecules began to emerge in bubbling form. Brant White, a program manager at Sierra Space, stated, 'We’ve tested everything we can on Earth now. The next step is going to the moon. ' This experiment took place at NASA’s Johnson Space Center during the summer months. It is important to note that Sierra Space is not alone in this endeavor; numerous researchers are actively developing technologies that could provide essential resources for astronauts residing on a future lunar base. These astronauts will require oxygen not only for breathing but also for producing rocket fuel for spacecraft that may launch from the moon to explore further destinations, including Mars. Additionally, inhabitants of a lunar base may need metals, which could potentially be extracted from the dusty grey debris scattered across the moon's surface. The success of these efforts largely hinges on our ability to construct reactors capable of efficiently extracting such resources. Mr. White emphasized the potential cost savings, stating, 'It could save billions of dollars from mission costs. ' He explained that the alternative—transporting large quantities of oxygen and spare metals from Earth—would be both labor-intensive and financially burdensome. The chamber in which the experiments were conducted is designed to replicate the pressures and temperatures found on the moon. Inside this spherical chamber, the machine operates under conditions that simulate the lunar environment. Fortunately, lunar regolith is rich in metal oxides. However, while the science behind extracting oxygen from metal oxides is well understood on Earth, performing this process on the moon presents significant challenges. The primary difficulty arises from the unique conditions present on the lunar surface. The large spherical chamber that hosted Sierra Space’s tests in July and August was engineered to create a vacuum and simulate the extreme temperatures and pressures of the moon. The company has had to continually refine the machine's functionality to ensure it can withstand the abrasive and jagged texture of the regolith. Mr. White noted, 'It gets everywhere, wears out all sorts of mechanisms. ' One critical aspect that cannot be tested on Earth or even in low Earth orbit is the moon's gravity, which is approximately one-sixth that of Earth's. It may not be until 2028 or later that Sierra Space can conduct tests on the moon using actual regolith in low-gravity conditions. NASA's Artemis mission is scheduled to land astronauts on the moon in 2027. The moon’s gravity could pose significant challenges for certain oxygen-extraction technologies unless engineers design them specifically for this environment, according to Paul Burke from Johns Hopkins University. In April, he and his colleagues published findings from computer simulations that indicated how a different oxygen-extraction method might be hindered by the moon’s relatively weak gravitational pull. This method, known as molten regolith electrolysis, involves using electricity to separate lunar minerals containing oxygen to extract the oxygen directly. The challenge lies in the fact that this process generates bubbles of oxygen on the surface of electrodes submerged deep within the molten regolith. Dr. Burke explained, 'It is the consistency of, say, honey. It is very, very viscous. ' This viscosity means that the bubbles may not rise quickly and could become trapped. However, there are potential solutions to this issue. One approach could involve vibrating the oxygen-producing machine to help dislodge the bubbles. Additionally, using smoother electrodes might facilitate the detachment of the oxygen bubbles. Dr. Burke and his team are currently exploring these possibilities. Sierra Space’s technology employs a different method known as the carbothermal process. In this case, when oxygen-containing bubbles form in the regolith, they do so freely, rather than being restricted to the surface of an electrode. This design reduces the likelihood of the bubbles becoming stuck, according to Mr. White. Highlighting the importance of oxygen for future lunar missions, Dr. Burke estimates that an astronaut would require the equivalent of two to three kilograms of regolith per day to meet their oxygen needs, depending on their level of physical activity. However, life support systems on a lunar base would likely recycle the oxygen exhaled by astronauts, meaning that not as much regolith would need to be processed solely for survival. The primary application for oxygen-extraction technologies, Dr. Burke adds, lies in providing the oxidizer for rocket fuels, which could enable ambitious space exploration endeavors. Palak Patel, a PhD student at the Massachusetts Institute of Technology, is also investigating methods to extract oxygen and metals from lunar dust. She stated, 'We’re really looking at it from the standpoint of, ‘Let’s try to minimize the number of resupply missions. ’ In designing their system, Ms. Patel and her colleagues addressed the challenges posed by low gravity, which could impede the detachment of oxygen bubbles from electrodes. To overcome this, they utilized a device called a sonicator, which emits sound waves to dislodge the bubbles. Ms. Patel believes that future resource-extraction machines on the moon could yield valuable materials such as iron, titanium, or lithium from regolith. These resources could assist lunar astronauts in creating 3D-printed spare parts for their moon base or replacing components for damaged spacecraft. The potential applications of lunar regolith extend beyond resource extraction. Ms. Patel has also conducted experiments that involve melting simulated regolith into a durable, glass-like material. She and her team have discovered methods to transform this substance into strong, hollow bricks, which could be utilized for constructing structures on the moon.