COULD WE EAT OUR OWN POO?
Scientists at Penn State University have developed a novel way of making food, which would save us having to lug all of our food with us into space. Yesterday’s human waste is transformed into tomorrow’s lunch.
Urine is already recycled into drinkable water on the ISS, but faeces are sent away in a cargo vessel to burn up in Earth’s atmosphere. Dr Lisa Steinberg, who worked at Penn State before becoming a school science technician, saw this as a wasted opportunity, and developed a system to reuse all of our bodily outgoings.
“The system is composed of two reactors,” she says. “The first takes urine and faeces and converts part of the carbon [in the waste] into methane, which is fed to a second reactor growing a methane-consuming bacterial biomass.” The result is a high-protein, high-fat food supplement. Steinberg points out that the food can be grown within a few days – much quicker than plant-based protein sources such as soybeans. However, she cautions that it “would likely complement, not replace, vegetable matter in an astronaut’s diet.”
Is it safe? “[The reactors] only transfer gaseous products, which can be easily filtered to remove pathogens,” she says. “Safety was an important priority.” As for the taste, Steinberg’s team weren’t able to sample the food due to lab protocol, but the texture has been described as similar to Marmite. Whether astronauts can be convinced to eat it is another matter.
One of the International Space Station’s two toilets