Human waste could soon be engineered to 3D print equipment for long space journeys

Researchers have developed a way that could help astronauts recycle their waste for producing products needed for long space journeys.

The experts from Clemson University presented their work at the National Meeting and Exposition of the American Chemical Society in a bid to change how astronauts handle their waste in space. According to them, unlike people on Earth, spacefarers - on journeys spanning several years - won't want to throw any waste, because waste molecules can be repurposed to produce something useful for such trips, for instance, polyesters and nutrients.

With that in mind, the team started exploring various ways to treat and recycle waste - generated primarily by eating, breathing, and using materials. They soon discovered that biological waste such as urine and exhaled air can be used to fuel a yeast called Yarrowia lipolytica for creating polymers.

A variety of yeast strains, according to their work, can grow using nitrogen from untreated urine and carbon from the exhaled air. The engineered strains can then be used to produce nutrients such as omega-3 fatty acids, which contribute to heart, eye and brain health, and monomers that can be linked to create polyester polymers.

The nutrients, which last only for a few years, can be produced during the journey or after reaching the destination, but the polymers can be 3D printed during the journey to produce plastic parts needed for different purposes.

Carrying added weight on long space trips - such as to Mars - has been a longstanding issue for spaceflight experts. The more weight (space parts and other equipment) astronauts take on board, the more fuel they'll need to sustain the journey. However, the ability to recycle waste into useful products or parts could be a smarter way to maximize the utility of everything that's on board.

"Having a biological system that astronauts can awaken from a dormant state to start producing what they need, when they need it, is the motivation for our project," Mark Blenner, a researcher working on the project, told Phys.org.

Though Blenner and his teammates can only engineer small amounts of polyesters and nutrients at this moment, the group believes they can boost the output in coming years. The system could be used on Earth for human nutrition and fish farming. They also plan to produce a variety of monomers for creating different types of polyesters with varying physical properties.