Could we really mix feces into Martian dirt and grow potatos?
In the bestselling sci-fi novel and upcoming movie "The Martian," astronaut and botanist Mark Watney survives on Mars for over a year, largely thanks to his ingenious potato crop.
But is it possible to actually grow food in Martian soil? Yes, and not just potatoes, says Bruce Bugbee, a real-life botanist and NASA scientist.
In "The Martian," Watney grows his own food by planting potato eyes in the ground. He fertilizes the plants with human waste and creates liquid water out of rocket fuel. There's no reason why this wouldn't work, says Bugbee, director of the crop physiology lab at Utah State University, with one critical caveat:
"The book (and probably the movie) suggests that the human waste is put right on the plants," Bugbee told Tech Insider in an email. "This would be microbiologically dangerous and probably toxic to the plants. The waste has to be composted first - usually for several months in a rotating drum."
Jim Green, director of planetary science at NASA and a consultant on the film, said there's probably an easier method than the one used by Watney, played by Matt Damon in the upcoming movie (due out Friday, Oct. 2).
We know that Mars has frozen water and the soil contains nitrate, which is "a great fertilizer," Green told Tech Insider. With so much nitrate, he may have not needed all that "homemade" fertilizer.
Green also noted Watney also could have skipped the dangerous chemical reaction needed to transform rocket fuel into water. Instead, Watney could have figured out a way to extract water from below the surface - now more of a certainty, thanks to recent news of flowing water on Mars - or suck it right out of the air.
In fact, NASA has already grown food in soil designed to mimic what we know so far about the pH and chemical makeup of real Martian dirt. Scientists have successfully grown over a dozen kinds of crops in the simulated grit.
It's worth nothing that a typical diet on Earth is the product of around 1,000 crops, Bugbee said. While we can't grow all those on Mars right away, it's a good start.
And crops on Mars would have other uses beyond food. Mars' thin atmosphere has a lot of carbon dioxide, which plants use to store energy from the sun. Plants take in carbon dioxide and release oxygen, so crops could be critical if humans ever attempt to transform Mars into a more hospitable planet - one with a breathable atmosphere.
Maybe something similar to Watney's precious potato crop will get us started.