Forget space-traveling robots powered by solar panels or nuclear energy. That's so 2011. Scientists at the U.S. Naval Research Laboratory are investigating whether naturally occurring bacteria found in soil could be used to power mini robots -- or microrovers -- sent on long research missions to explore distant planetary bodies.
The NRL is working to design a 2-pound microrover robot (or nearly one kilogram) that is powered by advanced microbial fuel technology and can operate in environments like space where the option for human intervention is non-existent, space robotics scientist Dr. Gregory Scott said in a release this week describing the project.
Energy generated by the microbial fuel cell will be used to operate onboard electronics and control systems. The remaining energy will be used to slowly charge a battery or capacitator. Once enough power has been stored, the robot can tap into it to operate an energy-intensive scientific instrument or propel itself forward with a hopping or tumbling motion, according to the NRL.
Using microbes as a power source isn't as unbelievable as it might sound. All microbes have the potential to create electricity because biological processes, such as digesting food, work by passing electrons. Scientists at the NRL have honed in on the anaerobic bacterium (meaning it doesn't require oxygen) Geobacter sulfurreducens as the core of its microbial fuel cell-based system.
The Geobacter species have rather novel electronic capabilities, including the ability to harvest electricity from waste organic matter and renewable biomass, according to the Geobacter Project out of the University of Massachusetts Amherst.
Geobacter form thick conductive films -- a property that makes them very well suited as anode catalysts for use in fuel cells -- enabling power generation from biomass derived fuels that are relatively high in energy, but non explosive, Dr. Leonard Tender, a research chemist at NRL Center of Biomolecular Science & Engineering, explained in a recent email.
NRL scientists chose to use microbial fuel cell technology because of its long-term durability -- thanks to the ability of microorganisms to reproduce -- and the bacterium's high energy density compared with traditional lithium-ion power sources.
Still, there are challenges to using microbial fuel cells as a power source. Namely, that they emit a low flow of power. Scott told me in a phone interview that in they'll work on improving the efficiency of the microbial fuel cell; develop the locomotion system that is lightweight and functional, even on a low flow of power; and finally, on the electronics used in the system itself. It's critical, for example, for the team to reduce the bulky infrastructure and equipment -- like large, power intensive pump and organic material-holding tanks -- used in microbial fuel cells.
As exciting as the project is, the microrover is still a very long way from exploring space. The research project is one of 30 funded by NASA Innovative Advanced Concepts program. Of those, only a handful will receive funding for another two years. Qualified projects will then receive funding to complete their projects. Scott expects in 10 years the scientists will develop a fully capable system.
The Naval Research Laboratory isn't the only institution working on using microbes to power devices. University of Saskatchewan grad student Jonathan Godwin is improving the technology and hopes to make a microbe-based fuel cell that is cheap and non-toxic.
Photo: U.S. Naval Research Laboratory