Electron microscope image of the microbe, Geobacter sulfurreducens, the core of the microbial fuel cell-based system. Image: U.S. Naval Research Laboratory
Robotic exploration to remote regions, to include distant
planetary bodies, is often limited by energy requirements to perform, in
repetition, even the simplest tasks. With this in mind, researchers at the U.S.
Naval Research Laboratory (NRL) are looking into a novel approach that could
some day aid scientific space and planetary research without the need for
power-intense options often used today.
Integrating the NRL developed technologies in microrobotics,
microbial fuel cells, and low power electronics, space robotics scientist Gregory
P. Scott at NRL’s Spacecraft Engineering Department inspires a novel autonomous
microrover, weighing in at nearly 1 kg and powered by an advanced microbial
fuel cell (MFC) technology.
“The goal is to demonstrate a more efficient and
reliable energy source for use in powering small robotic vehicles in
environments where the option for human intervention is non-existent,”
said Scott. “Microbial fuel cells coupled with extremely low-power
electronics and a low energy requirement for mobility addresses gaps in power
technology applicable to all robotic systems, especially planetary
The MFC was selected because of its long-term durability
owing to the ability of microorganisms to reproduce and the bacterium’s high
energy density compared with traditional lithium-ion power sources. This
research explores in more detail the use of microbes as a power source and
moves to eliminate the existing bulk associated with MFC infrastructure, such
as large, power intensive pump systems and MFC mass and volume requirements.
A portion of the energy generated by the MFC will be used to
maintain onboard electronics and control systems with the remaining energy
directed toward slowly charging a battery or capacitor until a sufficient
amount of electricity is collected. Once sufficient power is stored, the system
can then discharge this collected energy to activate a more power intensive
scientific instrument or to propel the rover forward using a novel tumbling or
hopping locomotion system.
Focusing on a pure culture anaerobic bacterium, such as Geobacter sulfurreducens, as the core of
the microbial fuel cell-based system, the power generation technology for this
research would have an exceptionally long lifetime, beneficial for recharging
onboard batteries or capacitors and providing for long-duration scouting
“As we move forward in the utilization of MFCs as an
energy generation method, this research begins to lay the groundwork for low
powered electronics with a long-term potential for space and robotic
applications,” adds Scott.