If humans survive on Mars, it will mean maximizing all available sources, including astronauts' urine. Scientists have come up with an idea of a recycling system that uses sunlight to produce rocket fuel from this wastewater.
They propose using a reactor that will produce space propellant on Mars using the air on the Red Planet, which is 95% made up of carbon dioxide. This reactor will be powered by sunlight and urine of astronauts in a process that would also detoxify the water used, serving as a recycling method like what Matt Damon did in his film "The Martian."
The First Reactor to Produce Eco-Friendly Rocket Fuel
A Spanish team of engineers from Tekniker is developing the recycling reactor, ESA reported. Borja Pozo from Tekniker said they aim to make the first reactor to produce a space propellant on Mars using the carbon dioxide in the planet's atmosphere.
European Space Agency's (ESA) technical officer Jean-Christophe Berton said that the outcome of the project could provide the space agency with important input on producing rocket fuel for Mars exploration or to power remote ground stations on Earth. Also, it could potentially offer input on how to decarbonize Earth's atmosphere.
The engineers explained that the photoelectrochemical system would be using high-efficiency catalytic materials to create hydrocarbons, like methane, carbon monoxide, and alcohols from the atmosphere carbon dioxide and astronaut urine.
Pozo pointed out that carbon dioxide has been proven a valuable resource to produce chemicals and fuel in space missions where materials are scarce. This proposed technological approach has caught the attention and interest of scientists for future deep space missions, particularly on Mars, where carbon dioxide is abundant in the atmosphere.
The idea is a sign of progress for photoelectrochemical (PEC) system, which is associated with reactor design, process control, and the development of innovative photoelectrodes. Pozo added that it would be interesting to combine sewage treatment with fuel production to provide an improved PEC system that will reduce carbon dioxide in the atmosphere.
"In this sense, the oxidation in a PEC cell of the organic content (including pathogens) of the sewage would allow detoxify the water and make it also reusable for other purposes," Pozo told ESA. The reduced electrons from this process would subtract carbon dioxide in the cathode to produce fuels by directly converting sunlight as a source of energy.
Other Innovations to Produce Rocket
According to MailOnline, Tekniker is not the first company to come up with the idea of producing alternative rocket fuel for the Mars mission. It is estimated that the crewed mission to the Red Planet will cost about $8 billion to ferry at least 30 tons of methane and liquid oxygen used to power rockets.
In October last year, Georgia Institute of Technology researchers proposed a novel method to generate rocket fuel using Martian natural resources. They aim to grow bacteria from these sources to transform them into rocket fuel.
The process involves building a giant photobioreactor, as big as a football field, on the Martian surface that will harness the power of sunlight and use carbon dioxide to create cyanobacteria that will produce sugars. The resultant Martain propellant will be called 2,3-butanediol, which is being used to make polymers for producing rubber on Earth.
Furthermore, another team from Washington University in St. Louis also expressed their interest in developing a system that transforms unstable water on Mars into fuel and oxygen. In 2020, they presented their concept that uses electricity to break the salty water on Mars into oxygen and hydrogen.
Researchers claim that this brine electrolyzer could generate 25 times more oxygen than the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) of NASA that was also launched to the Red Planet aboard the Mars Perseverance rover in July 2020.
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