Every resource carried onto a manned spaceship is precious, because it costs hundreds of dollars to lift each pound of material past Earth's surly bonds. Now that NASA is in the process of planning a trip to Mars that might take up to two years, no type of recycling can be overlooked. One thing that can provide three basic raw materials (water, energy, and fertilizer) needed for a long space journey: human waste.
Most methods of recycling organic waste involve the production of methane, a flammable gas that can easily turn a closed spaceship into a roman candle. That's why NASA awarded a $100,000 (US) grant to Bruce Rittmann, an environmental engineer at Northwestern University, Evanston, to build a microbial fuel cell that generates electricity from sewage.
Such fuel cells function like a conventional fuel cell, except that individual bacterial cells split electrons from a food source and transfer them ...
