New research describes in detail the biological solution for the production of rocket fuel on Mars, but significant obstacles need to be overcome for this intriguing idea to succeed.
With plans to visit Mars in the next decade, NASA is still tackling the fuel situation; launching a rocket to the Red Planet is not a problem – it is a challenge to get the vehicle off the surface to return home. Abundant amounts of methane and liquid nitrogen will be needed to produce the required propellant, but these key components of rocket fuel are rare on Mars as are refineries.
New research published in Nature Communications estimates the cost of $ 8 billion to ship the required 30 tons of methane and liquid oxygen to Mars. And only for one launch with a carrying capacity of 500 tons! With the financial support of NASA’s Innovative Advanced Concepts program, the authors of the new work came up with a completely different solution, in which the key ingredients needed to produce propellant can be obtained directly on the Red Planet.
These ingredients include carbon dioxide, frozen water and sunlight. Cyanobacteria, also known as blue-green algae, and a bioengineered strain E. coli the bacteria would be brought to Mars from Earth, along with the materials needed to build a large array of photobioreactors. Nick Kruyer, the first author of a new study and researcher at Georgia Tech School of Chemical and Biomolecular Engineering, and his colleagues outlined a production strategy in which cyanobacteria, driven by sunlight and carbon dioxide, produce sugars that E. coli it is then converted to a sustainable propellant.
Called 2,3-butanediol, it is not the most energetic propellant ever invented, but in a relatively low-gravity environment on Mars, this rocket fuel will do the job, the researchers claim. As a compound, 2,3-butanediol is already well known, because it is used in the production of rubber, but scientists have never thought of using it as a propellant.
Other scientists have suggested that methane is the only solution, “because it is a high-energy fuel that can be chemically produced from carbon dioxide, which is abundant on Mars,” Pamela Peralta-Yahya, co-author of the study and associate professor at the School of Chemistry and Biochemistry at Georgia Tech, he explained to Gizmoda in an email. “A key insight of this paper is that a wider range of chemicals can be considered for use as propellant because Mars has one-third of Earth’s gravity – so you can use lower-energy rocket fuel.”
Plastic materials shipped to Mars would be assembled into a photobioreactor array the size of four football fields. Photosynthesis and carbon dioxide would allow the growth of cyanobacteria, while enzymes in a special reactor would break down microorganisms into sugar. As Kruyer pointed out in a press release, “biology is particularly good at converting CO2 into useful products,” making it “well suited to making rocket fuel.” On E. coli phase, separating the propellant from the fermentation broth would result in a purity of 95%, the paper states.
Bioproduction of Martian rocket fuel would require 32% less energy than NASA’s proposed chemical solution – that is, the plan to ship large quantities of methane to Mars. That it would produce 44 tons of excess pure oxygen, which astronauts would make good use of. Moreover, the proposed chemical solution would create carbon monoxide as a by-product, “which should be purified,” Peralta-Jahja said. “Electrolysis of water is planned, but that chemical … strategy is at a lower level of technological readiness,” she added.
As for the reduction of the total cost of the venture, it is less obvious, because this solution would require 2.8 times more mass of cargo than the proposed chemical strategies, scientists say. That is significant. Researchers will need to reduce the weight of the equipment, such as minimizing the size of the photobioreactor.
In addition, the “key contribution” of the new work is the “identification of achievable” optimization solutions to reduce payload while using 59% less energy than NASA’s methane. plan, explained Peralta-Yahya. “Such optimizations include improving the growth rate of cyanobacteria at low temperatures, which would lead to smaller cyanobacterial farms,” she added.
Georgia Tech engineer and study co-author Matthew Realff said the team will have to conduct experiments to show that cyanobacteria can indeed be grown on Mars. The team should consider the difference in the solar spectrum on Mars both because of the distance from the Sun and the lack of atmospheric filtering of sunlight, “he explained in an e-mail, while noting that” high levels of ultraviolet radiation can damage cyanobacteria. “
Researchers will also need to be careful about contaminating Mars with our microbes. It certainly contains cyanobacteria and E. coli it will be a necessary step in ensuring that astrobiologists can continue to look for signs of past life on Mars without the interference of terrestrial organisms.
NASA’s current planetary protection guidelines explicitly prohibit the sending of microbes to the surface of another planet, but as Peralta-Yahya explained, “biotechnological applications on Mars have the potential to provide clear advantages over chemical processes.” To make their solution safe, the team would develop and test a number of retention strategies, such as physical barriers, killing switches, and projected microbes that are unable to survive outside the reactor.
Scientists have proposed a fascinating solution to a serious problem. Yes, there is a lot of work left, but it is a good start. Mars may be a barren desert, but it is not completely resourceless. We just have to find ways to use them to our best advantage.
More: Martian colonists could use their own blood to produce concrete, new research suggests.
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