One of the challenges we face in our quest to colonize Mars is a lack of fuel. If humans on Mars want to return to Earth, they’ll need enough fuel for the launch and return trip, which will be a huge logistical challenge due to the weight of rocket fuel.
Fortunately, scientists believe that microbes may hold the key to producing the fuel required on Mars. Georgia Institute of Technology researchers have developed a concept for producing Martian rocket fuel on Mars, which could be used to launch future astronauts back to Earth.
According to a press release from Georgia Tech, the researchers’ study, published in Nature Communications, discovered that cyanobacteria, along with a strain of E. coli bacteria, could be used to create rocket biofuel. The microbe could produce sugars that E. coli could convert into a usable propellant called 2,3-butanediol with the help of a photobioreactor built on the Martian surface (2,3-BDO).
On Mars, you need a lot less energy for lift-off, which gave us the flexibility to consider different chemicals that aren’t designed for rocket launch on Earth. We began to think about how we could use the planet’s lower gravity and lack of oxygen to create solutions that aren’t relevant for Earth launches.
Pamela Peralta-Yahya
The bioproduction process would make use of three resources found on Mars: carbon dioxide, sunlight, and frozen water. It would also entail sending two microbes to Mars. The first would be cyanobacteria (algae), which would take CO2 from the Martian atmosphere and convert it into sugars using sunlight. An E. coli engineered on Earth would convert those sugars into a Mars-specific propellant for rockets and other propulsion devices. The Martian propellant, known as 2,3-butanediol, is currently in existence, can be produced by E. coli, and is used to make polymers for the production of rubber on Earth.
Low Gravity Boost
Though 2,3-BDO isn’t as powerful a propellant as what we typically use in launches, the paper’s authors believe that due to Mars’ lower gravity, it could be enough to get the job done.
“On Mars, you need a lot less energy for lift-off, which gave us the flexibility to consider different chemicals that aren’t designed for rocket launch on Earth,” said Pamela Peralta-Yahya, coauthor of the study and an associate professor of chemistry and biochemistry at Georgia Tech, in a press release. “We began to think about how we could use the planet’s lower gravity and lack of oxygen to create solutions that aren’t relevant for Earth launches.”
Although 2,3-butanediol is a weaker rocket fuel than methane, Mars’ gravity is only one-third that of Earth. “Lift-off on Mars requires a lot less energy, which gave us the flexibility to consider different chemicals that aren’t designed for rocket launch on Earth,” Peralta-Yahya said in a statement. “We began to think about how we could use the planet’s lower gravity and lack of oxygen to create solutions that aren’t relevant for Earth launches.”
This strategy also necessitates the shipment of enzymes to Mars in order to digest the cyanobacteria and liberate their sugars. To extract the 2,3-butanediol from the E. coli fermentation broth, industrial separation techniques are also required.
Building Bioreactors
According to the release, the process of producing enough propellant for the trip back to Earth would necessitate the construction of a photobioreactor the size of four football fields. The system would run on carbon dioxide and sunlight, both of which are abundant on Mars.
According to the release, the process would also drastically reduce mission costs while producing 44 tons of excess clean oxygen that could be used to keep the humans alive.
The team’s research was funded and supported by NASA’s Innovative Advanced Concepts Award in 2020, indicating that the agency takes the idea seriously. If successful, it will make trips to Mars — as well as returns — more affordable than ever.
