In The Martian, Matt Damon used his own shit to fertilize potatoes and survive the Red Planet. While we all know Matt Damon isn’t actually an astronaut, we do know that human excrement is very much real—and it could be integral to getting real humans to Mars in the near future.
Researchers from Clemson University are studying how molecules from astronauts’ sweat and pee can be converted into plastics that can be used for tools aboard a spacecraft. The team is focusing on a strain of yeast called Yarrowia lipolytica, which astronauts would hypothetically feed with the carbon and nitrogen in their excrements. The yeast would then act like a “space recycler,” creating oils and fats that can eventually be crafted into bioplastics. Their work will be presented this week at the 254th National Meeting and Exposition of the American Chemical Society (ACS).
If all goes according to plan, the Yarrowia lipolytica will be engineered to create polyester, which we know as the stuff that makes kind of uncomfortable clothing. But on the long trip to Mars, this plastic can be fed into 3D printers, which will hypothetically be able to create tools for astronauts on demand. So if something breaks along the way—no worries! Something can whip up a pee tool in no time.
Astronauts on long missions won’t be able to pack a ton of extra gear for their trips, since this would make the ship heavier and add to fuel costs needed to blast the spacecraft out of Earth’s orbit. Because long-duration spaceflight will require astronauts to be extra thrifty, recycling pee actually makes a lot of sense when you think about it—in fact, astronauts are already doing this in a different capacity aboard the International Space Station (ISS).
“We currently drink our processed pee and sweat on the ISS,” former NASA astronaut and STEAM educator Leland Melvin told Gizmodo. “Things like pee, poo, [and] hygiene are so important. They are the basic things that—if you don’t get right—kills the mission because people can get sick. But on the flip side, it cuts down on your consumables when what has historically been your trash basically becomes your treasure.”