Microbial Robots in Outer Space!

NASA's Martian rover Curiosity is five times larger than its predecessors — about the size of an SUV — says Wired UK's Mark Brown. The energy needed to power it comes from a radioisotope power system. But researchers at the US Naval Research Laboratory would like to develop rovers about the size of a bag of sugar, and as such, need a smaller way to power the machines, Brown says. Well, you can't get much smaller than a microbe. "Gregory Scott at NRL's Spacecraft Engineering Department has been awarded a NASA Innovative Advanced Concepts research grant to investigate the initial phase of tiny planetary robots that are powered by bacteria," Brown reports. "Micro-robotic explorers, powered by microbial fuel cells, could represent an efficient and reliable energy source on a planet without human intervention." Such a microbial fuel cell would use the bacteria's metabolic processes to harvest electrons, and then send those through a circuit to generate electricity. Some of the energy produced by the bacteria could be used to maintain the rover's electronics and controls, while the rest could go toward charging a battery or capacitor, Brown says. With a fully charged battery, the rover could be able to perform more complicated tasks. NRL's Scott plans to focus his research on anaerobic bacteria like Geobacter sulfurreducens, Brown says.