In the future, farmers on the Moon and Mars will face a major challenge: how to grow healthy food in two extremely unhealthy environments. That’s because the soil in both worlds is completely unsuitable for plants and animals. The same applies to other conditions. Both are irradiated worlds, with Mars having a thin atmosphere and the Moon having none at all. So how would future colonists of either world grow food?
We can look to the example Matt Damon gave in “The Martian.” A stranded Martian astronaut finds a way to grow potatoes using his own sewage. Experiment conducted by the International Potato Center and NASA years ago. More recently, researchers led by Texas A&M’s Harrison Coker collaborated with a team at NASA to test recycled wastewater product solutions and how they interact with simulated lunar and Martian regolith. A NASA team headquartered at Kennedy Space Center is taking a closer look at so-called bioregenerative life support systems (BLiSS). These bioreactors and filters turn man-made forms of sewage into a solution rich in the types of nutrients needed for plant growth. This research has a direct impact on the people who will live and work on the Moon and Mars in the future. This is because people can easily provide the waste they need. In the upcoming Artemis mission to the moon, The issue of food production is considered a high priority for long-term residents.
“Organic waste may be key to producing healthy, highly productive soils on a lunar or Martian outpost. By weathering a simulated lunar or Martian soil with an organic waste stream, we show that many essential plant nutrients can be harvested from surface minerals,” said Coker, lead author of the study of such systems.
A mock lunar greenhouse at NASA Kennedy Space Center is helping scientists solve the problem of growing food on the Moon, and eventually Mars. Courtesy of NASA.
What do plants need?
Plants on Earth require complex nutrients to thrive. For example, corn requires large amounts of nitrogen. Peas like potassium and phosphorus. Potatoes like both phosphorus and nitrogen. And every planet needs water. The researchers considered what it would take to “enrich” the regolith on Mars and the Moon. As it turns out, they need a lot of stuff. That’s because the soil is irradiated and, in the case of Mars, rich in sulfur, ferric oxide, silicon dioxide, and magnesium. It also contains high concentrations of toxic perchlorate.
The first inhabitants of these worlds brought their own food and sewage systems, and then must work to make the local soil conducive to plant life. That takes time and a lot of effort, on top of all the other projects that need to be accomplished, such as exploration and habitat construction.
Of course, future residents may rely on hydroponics as a growing medium, and a huge amount of research is being conducted on such water-based systems. However, producing large amounts of food requires large amounts of water and a very high nutrient load. At least on the moon, astronauts could send supplies back to Earth, but that would be expensive and time-consuming. Therefore, the first explorers likely relied on food from “home.” But that’s not a permanent solution, so scientists are looking for ways to make local soils suitable for agriculture in the long term.
*Research on growing food in space goes back many years. A red potato variety called Norland was grown in a biomass production room in Hangar L at Cape Canaveral Air Force Station, Florida, during a 1992 research study. Credit: NASA*
Better agriculture through sewage and chemistry
In the study led by Coker and others at NASA, the scientists combined the BLiSS effluent they created with simulated Mars or lunar regolith (called simulants, respectively). The two different solutions were then stored in a shaker for 24 hours. The goal was to determine whether BLiSS effluent could essentially “weatherize” the regolith and provide a nutrient-rich growth solution.
It turns out that weathered analogues provided plants with large amounts of essential nutrients. They include sulfur, calcium, magnesium, and other metals when interacting with both water and BLiSS solutions. Furthermore, when particles of the pseudomaterial were observed under a microscope, weathered features were revealed, such as the formation of small holes in the lunar pseudomaterial and the covering of nanoparticles in the Mars pseudomaterial. Both help reduce the abrasiveness of the sharp minerals found in the imitations, indicating successful weathering and a step toward more earth-like materials.
So is recycling human waste the solution to making extraterrestrial gardens better? Not completely. Despite promising initial results, next steps must include testing on actual lunar and Martian regolith. They are completely different from similar substances that scientists have tested. But it’s a good start and provides important insight into processes critical to sustaining human colonies in outer space. It may not be long before Moon residents are snacking on watercress sandwiches and Mars colonists are using their own runoff to grow corn, beans, and, yes, potatoes.
For more information
How recycled sewage could make the moon and Mars suitable for growing crops
Human exploration beyond low Earth orbit: the gradual evolution of BLiSS technology