Dreams of reaching distant planets or even colonizing our own moon are dependent on being able to grow vast quantities of food. Growing it hydroponically is an option but that technology requires a lot of water, which presumably will also be in short supply in outer space. The easiest solution would be the ability to grow food on other planets or satellites. For the first time, researchers have been able to grow plants in the Moon’s equivalent to soil, called regolith, which produced some unexpected results.
The surface of the Moon as well as other planets is far different than what’s found on Earth. The soil, called “regolith,” is a loose, dusty material devoid of any organic matter. Since the Moon lacks any sort of an atmosphere, the upper few layers of the regolith are exposed to the bombardment of micrometeorites and to solar wind irradiation.
NASA scientists began using simulated Moon “soil” to prepare for the first Apollo mission in 1968. After acquiring actual samples from the Moon on several of the following missions, researchers were able to produce fake soil materials that simulate the real thing. The simulated Moon soil NASA uses today is called JSC-1A. There are key chemical and physical differences between JSC-1A and real lunar regolith, however, and a group of researchers at the University of Florida wanted to find out what those differences could mean for growing plants.
Real lunar regolith is an extremely rare substance here on Earth so they were only able to secure a minuscule 12 grams or less than 3 teaspoons. To accommodate the tiny amount of regolith, the researchers used thimble-sized wells in plastic plates normally used to culture cells. Each well functioned as a pot. Once they filled each “pot” with approximately a gram of lunar soil, the scientists moistened the soil with a nutrient solution and added a few seeds from the Arabidopsis plant. As a control, the researchers also planted Arabidopsis in JSC-1A.
Before the experiment, the researchers weren’t sure if the seeds planted in the lunar regolith would even sprout but to their amazement, nearly all of them did. “That told us that the lunar soils didn’t interrupt the hormones and signals involved in plant germination,” study co-author Anna-Lisa Paul explains.
However, as time went on, the researchers observed differences between the plants grown in lunar soil and the control group. For example, some of the plants grown in the lunar soils were smaller, grew more slowly or were more varied in size than their counterparts. All of the lunar soil plants also had altered pigmentation. These are all signs that the plants were working to cope with the chemical and structural make-up of the Moon’s soil, Paul explained. This was further confirmed when the researchers analyzed the plants’ gene expression patterns.
The plants grown in lunar soil activated many of the genes involved with stress responses, including those involved with phosphate starvation, metal toxicity, and reactive oxygen problems. The plants with the most signs of stress were those grown in what lunar geologists call mature lunar soil. These mature soils are those exposed to more cosmic wind. Plants grown in comparatively less mature soils did fare better but still showed extreme signs of stress.
The big takeaway is that soils on the Moon or other planets would likely need a massive amount of amendments in order to provide any significant food supplies. The soil composition would also need to be changed in more and different ways than initially believed based on the poorer performance against NASA’s soil simulate. Meaning we either need a lot more lunar regolith or a better soil simulate in order to figure it out. Some researchers also believe it might be possible to genetically engineer crops that are more suited to these harsh environments. Researchers are also curious how growing plants on the lunar surface might change the regolith itself.
Follow-up studies will build on these questions and more. For now, the scientists say they are celebrating having taken the first steps toward growing food on the Moon. The UF researchers have a YouTube video explaining more about the experiment HERE. (Sources: NASA, ArsTechnica, SpaceRef, Nature)
