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Artificial Photosynthesis Could Help Astronauts Breathe on Mars
That seems important.
In SYFY’s The Ark (streaming now on Peacock), the crew of the Ark One is farther from home than anyone has ever been before. Adrift between star systems, they must create, recycle, and maintain critical resources for their survival. Key among them is oxygen; without air to breathe, any long-term survival plans are irrelevant. If real world humans want to make a go of it in space, we’re going to need to figure out how to get hold of food, water, and air at our destination. Fortunately, a recent study published in the journal Nature Communications explores the possibility of creating oxygen from scratch through artificial photosynthesis.
The Second Leg of the Space Race
NASA is only one among a growing list of global space agencies and commercial companies with their sights set on the rest of the solar system. With the Artemis program in full swing, it won’t be long before people are back on the Moon. Once a more permanent presence is established on the Moon, it will be used as a jumping off point for Mars and beyond, in the coming decades. To pull that off, scientists, engineers, and explorers are going to need to build a lot of infrastructure along the way.
Meanwhile, commercial companies are working toward a tourism and mining economy in low-Earth orbit, all of which will require basic survival resources to maintain. While pitstops in low-Earth orbit have the benefit of quick resupplies from the ground, the same can’t be said of more distant locales. Getting to Mars takes months at the best of times, you can’t exactly order up a batch of oxygen for next-day delivery.
On the International Space Station (ISS), astronauts utilize the Environmental Control and Life Support System (ECLSS) to provide oxygen. It works by using electricity from the station’s solar panels to break water into hydrogen and oxygen gas. Then a separate system pulls carbon dioxide out of the air and turns it into water and methane. Those systems take up a lot of space and they’re power hungry, gobbling up about a third of all the power that the station’s impressive solar arrays produce.
The ISS can afford to be inefficient because it’s so close to home, but that won’t be true of astronauts setting up shop on the Red Planet. They’re going to need a better solution.
Taking Space Travel Cues From Plants
There was almost no oxygen in the atmosphere of the early Earth. When the first lifeforms emerged, they gobbled up CO2 in the atmosphere, combining it with water and sunlight to create sugar for them to live on. They also created oxygen as a chemical biproduct. Over the course of millions of years, those simple life forms became so successful that they transformed the atmosphere, filling it with enough oxygen for more complex life to evolve.
Those photosynthesizing lifeforms stuck around and evolved, too, becoming every form of grass, flower, tree, moss, and algae. And we owe them every breath we take. Without plants, it’s estimated the world’s supply of oxygen would vanish in about 5,000 years. Of course, we’d have bigger problems if there were no plants.
On Mars, unfortunately, there are no plants. So, if we want to make oxygen from scratch, we’ll have to do it artificially. Instead of chlorophyll, which plants use to absorb sunlight, scientists propose a photoelectrochemical (PEC) device which would use semiconductor materials coated with metallic catalysts. That allows for the conversion of CO2 and water into oxygen gas and hydrogen or carbon-based fuels.
The atmosphere on Mars is much thinner than on Earth, but it’s almost 96% CO2, giving astronauts plenty of atmospheric material to work with. The only other ingredient, sunlight, is delivered freely to the surface. However, the amount of sunlight Mars receives is also considerably lower than on Earth, which will have an impact on the system’s efficacy. Scientists took that into account, however, and when they crunched the numbers, they found that solar radiation on Mars is sufficient to power their system and generate oxygen. That said, astronauts may need to set up a system of solar mirrors to gather sunlight from a wider area and concentrate it on the device.
Researchers essentially want to shortcut nature’s photochemical process so we can use it on other worlds. At least until we get the Martian agricultural system set up. Mars could use a little color.
Catch up on Season 1 of The Ark, streaming now on Peacock!