Scientists are slowly tackling the roadblocks to human life in space, including how to breathe without oxygen, how to build without bricks, and how to find food where there is none. In terms of the latter, a team from Canada's Western University has come up with what they say is a "promising" approach to feeding astronauts in space that won't require a link to Mother Earth: Have them feed on asteroids. Well, not asteroids exactly: Researchers suggest "potentially human-edible biomass" can be created from microbes and organic compounds found in asteroids, Live Science reports. The approach uses the process of pyrolysis, in which organic material is broken down when subjected to high heat in the absence of oxygen.
Though researchers haven't tested this with actual asteroid samples, they say heating organic compounds in carbonaceous chondrites—a type of asteroid containing lots of organic matter and up to 10.5% water, of which the near-Earth asteroid Bennu is one—would create hydrocarbons that could be fed to microbes found within the asteroid. "When the bacteria finish feeding, they themselves become the food," per the New York Times. "Researchers estimate that asteroids like Bennu could be used to produce about 50 to 6,550 metric tons of edible biomass with enough calories to support between 600 and 17,000 astronaut life years," depending on whether some or all organic matter can be converted into food, Live Science reports.
Astronauts aboard the International Space Station get food delivered from Earth. But "to deeply explore the solar system, it will be necessary to become less reliant on the resupply tether to Earth," reads the study published earlier this month in the International Journal of Astrobiology. It's not yet known how asteroids might be mined and processed in space, or whether the resulting biomass will be safe to eat. "This approach of using carbon in asteroids to provide a distributed food source for humans appears promising, but there are substantial areas of future work," the study notes. Luckily, samples from Bennu, returned to Earth last year, are now available for research. (Space farming is another possibility.)