The U.S. Naval Research Lab (NRL) has just won a grant from NASA to pursue creating Mars rovers powered by microbes. Researchers are hoping this would tackle the problem of providing a safer and more reasonably sized fuel cell to handle the long term needs of powering a rover and sending data all the way back to Earth.
It seems when it comes to rovers, bigger isn't necessarily better.
Why? Consider the fact the current fuel system is a bit like sending a nuclear reactor to Mars. They operate by generating electricity by harvesting the heat from the radioactive breakdown of a piece of plutonium. While they have been successful so far, they are bulky and could be safer…
Microbial fuel cells (MFC's) would generate electricity by harvesting power from the electron production occurring when a microbial metabolic process happens within bacteria stored within a fuel cell. The downsized fuel cells could provide continuous power, or charge a battery or capacitor to drive the more power hungry equipment.
With smaller fuel cells NASA could send an army of tiny rovers — each weighing no more than a kilogram — to more efficiently explore Mars.
While their smaller size is a benefit, there are some challenges posed by the MFC's.
The current prototype would work with the bacteria Geobacter sulfurreducens — an anaerobic organism that breaks down metal. That means the research thus far has focused on the energy created when a microbial community eats — not when they reproduce. Eating produces waste that would have to be disposed of so the colony isn't destroyed.
And while microbes aren't nuclear reactors, scientists will have to work on creating adequate protection to the microbial cells to protect them from the rigors of space travel. If the fuel cells are compromised there is the chance the microbes could die — or even introduce alien bacteria to another planet with unknown consequences.
The Navy has already successfully tested a form of microbial fuel cells by using the gas emitted from their metabolic processes to move sensors up and down in water, so they have a good head start on finding solutions to protect microbes in different environments.
With that in mind it may not be too long before we see these tiny little workhorses headed towards our favorite red planet.