Human waste mixed with simulated lunar and Martian soil can release key plant nutrients that are otherwise locked inside inorganic minerals, according to new research from Texas A&M University and NASA’s Kennedy Space Center. The findings suggest a practical, low-import path toward growing food on other worlds.
The study, led by Harrison Coker of Texas A&M, tested whether processed sewage effluent could chemically “weather” regolith simulants, freeing nutrients that plants need to grow. “In lunar and Martian outposts, organic wastes will be key to generating healthy, productive soils,” Coker said in a statement. “By weathering simulant soils from the moon and Mars with organic waste streams, it was revealed that many essential plant nutrients can be harvested from surface minerals.”
The Problem With Extraterrestrial Dirt
The surface material on the moon and Mars is called regolith, not soil, for a reason. It is entirely inorganic. While regolith does contain nutrients bound inside minerals, those nutrients remain chemically inaccessible to plant life in their natural state. Without intervention, nothing grows in it.
Previous attempts to solve this included heat treatment, hydroponics, ionic liquids, and electro-deoxidation. Each method showed some promise, but all share a fundamental problem: they require chemicals, energy, or technology continuously imported from Earth, making them expensive and logistically fragile for deep-space settlements.
Mars compounds this problem significantly. The travel time and cost between Earth and Mars make routine resupply of fertilizers or specialist chemicals effectively impossible at any meaningful scale. Any long-term settlement has to produce what it needs on-site.
What the Experiment Actually Did
Coker and co-researcher Julie Howe, also of Texas A&M, partnered with NASA Kennedy’s bio-regenerative life support team, which operates a prototype system called the Organic Processing Assembly (OPA). The OPA runs sewage through a series of bioreactors and filters, producing a nutrient-rich effluent with toxins removed.
The team used simulated sewage and two regolith simulants, one representing lunar surface material and one representing Martian. Real Martian regolith does not exist on Earth, and genuine lunar samples are too rare and scientifically valuable to use in bulk experiments.
The effluent from the OPA was combined with each simulant and placed in a shaker for 24 hours to mimic the weathering process. Results showed the lunar regolith simulant released significant quantities of sulfur, calcium, and magnesium when exposed to the organic effluent.
Why This Approach Is Different
The core appeal of this method is self-sufficiency. Astronauts produce waste continuously. Regolith is available on the surface of both the moon and Mars in essentially unlimited quantities. Beyond the initial processing technology, neither input needs to come from Earth.
The concept echoes a now-famous plot point from Andy Weir’s novel and the subsequent film “The Martian,” in which a stranded astronaut fertilizes Martian regolith with human waste to grow potatoes. The science fiction scenario, it turns out, had more grounding in practical chemistry than it may have seemed.
The research points toward a closed-loop system where human biological output directly feeds agricultural input, reducing dependency on supply chains that span tens of millions of miles. Whether the nutrient yields are sufficient to sustain a growing crop at scale remains a question the team’s work has yet to fully answer.
Photo by Nicolas Lobos on Unsplash
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