In the fictional world, Matt Damon used his own poop to grow potatoes on Mars. In the real world, scientists just figured out another way human waste—in this case, urine—could benefit future astronauts. Their new study suggests astronauts could build shelters with lunar soil and human urine, reports CNET. More specifically, they would use urea, a component of urine, as a plasticizer, "helping to soften concrete-type mixes and make them more pliable before hardening," per a post at the Engineer. The researchers tested the idea while making "mud cylinders" from a substance similar to moon soil. They discovered that the urea compound "supported heavy weights" and remained largely stable, per a release from the Spanish Foundation for Science and Technology.
Both NASA and the European Space Agency (the latter was involved with this study) hope to build moon bases eventually, and a key part of that is reducing the prohibitive cost of shipping building materials up there. The current estimate to ship just 15.8 ounces of material to space is about $10,000. Using lunar soil and water from lunar ice would help. But "with this study we have seen that a waste product, such as the urine of the personnel who occupy the moon bases, could also be used," Ramon Pamies of Polytechnic University of Cartagena. He is one of the authors of the study in the Journal of Cleaner Production. One of the next steps is to figure out how astronauts would extract the urea from urine, or whether they could just use the urine itself. (Read more moon stories.)