The biggest challenge for a sustained human presence on Mars or the moon is how to bring enough supplies to sustain humans. One of the biggest challenges is bringing enough fuel for the rocket transporting the crew to Mars and having enough left over for the return trip. Many scientists believe the answer to that question is to harvest some of the materials needed for a sustained presence on the Red Planet from the planet itself.
Scientists at the Georgia Institute of technology have a new concept that will allow the manufacturing of rocket fuel on Mars that could be used to send the crew back to Earth when their mission is over. The bioproduction concept would leverage resources already native to the planet, including carbon dioxide, sunlight, and frozen water. However, the process would require the transportation of a pair of microbes to Mars.
One of the microbes is cyanobacteria (or algae) which would be leveraged to gather CO2 from the atmosphere of Mars and combined with sunlight to create sugars. The process also requires a special type of engineered E. coli bacteria to convert the sugar created by the algae into propellant for rockets and other devices. The rocket fuel created by the process is 2,3-butanediol, a propellant that exists already and can be created on Earth. However, on Earth, the propellant is required for making polymers to produce rubber.
NASA had proposed using a chemical catalyst for converting carbon dioxide into liquid oxygen. Still, that idea would have required methane to be transported to Mars along with the crew and other materials for the mission. The Georgia Tech process, on the other hand, would use resources already available on Mars and can reduce mission costs and complexity.
Another benefit of the process would be the generation of clean oxygen needed for sustained human presence. According to the researchers, their bio-ISRU process would generate 44 tons of clean oxygen for other purposes. Researchers outlined a process that would require NASA to send plastic materials to Mars that could be assembled into photobioreactors about four football fields in size. The cyanobacteria would grow inside the reactors utilizing carbon dioxide. The cyanobacteria would then be broken down into sugars fed to the E. coli to produce propellant. Finally, the propellant would be separated from the E. coli using advanced separation methods.