TWhile there were many obstacles in the Apollo missions, they did not have enough food. The longest any of the crews spent on the surface was the three days logged by Apollo 17 in 1972, and even in the astronauts’ tiny lunar module, there was enough room for the shrink-wrapped, pre-packaged provisions they’d need for such a brief camping trip. Things will change the next time.
As part of NASA’s Artemis program, which aims to return American astronauts to the moon after a half-century hiatus, crews won’t be coming just to visit, but to stay, establishing a long-term presence in permanent lunar bases. That means not carrying all of the crews’ food along, but growing at least some of it on-site—using the moon’s regolith, or soil, itself as a growth medium inside lunar greenhouses.
However, the question is whether this soil can sustain plant growth in a way that the loamy, rich soil on Earth, which has been bathed by solar radiation for many epochs, is the right answer. According to a recent study, the answer is yes. Communication Biology Maybe. Researchers tried for the first time to grow plants using lunar soil that was brought back from the Apollo missions. The success of your plant depends on which part of the moon it is.
The concept of extraterrestrial farming was widely popularized in Andy Weir’s book The Martian, in which a marooned astronaut grows potatoes in Martian soil, using human waste as a fertilizer—but Weir is by no means the first person to come up with the idea of tilling alien soil.
“This concept of growing crops and other plants in soil or regolith from the moon or from Mars has been around longer than I’ve been alive, so it’s hardly a new concept,” he tells TIME. Although it may not be true, this idea has been explored but never before.
This new research was the result of a lengthy process that involved two geologists from the University of Florida and one horticulturist. Over the last 11 years, the scientists had applied three times to NASA for soil samples that they’d brought back from the Apollo landings. Two times they were turned down. The third refusal was made 18 months later.
“With NASA prepping themselves to go back to the moon for longer excursions, it became much more relevant that we understand how resources that are in situ on the moon can be used to further exploration,” said horticulturist and lead author of the paper Anna-Lisa Paul, at a May 11 press conference announcing the release of the results.
The space agency didn’t turn over any of its soil, however. NASA gave the researchers 12 gm (or 0.42 oz) total soil from Apollos 11, 12, 17 and 18. Just 382kg (842lb.) was returned from the Apollo landings missions. of lunar rocks and soil—which sounds like a lot but actually makes the material exceedingly rare. “These samples are precious natural treasures,” said Paul.
This resulted in a small amount of crop. They used thimble-sized, plastic plates to plant their cell cultures. Each well got a gram of soil—or about a teaspoon—with four wells apiece for each of the three Apollo missions. The four remaining wells were then filled with a fake lunar soil, mainly made of fine volcanic ash. This was used to control. Researchers chose the thale cress as the plant to study.Arabidopsis ThaianaThis was selected for its durability and complete genetic sequencing.
“We know an awful lot about this plant from every nucleotide in its genome to what genes are expressed in different nutrient conditions,” said horticulturist and co-author Rob Ferl at the press event. “So there’s a huge database.” That basic knowledge would make it possible to determine exactly what was allowing the plant to thrive—or preventing it from doing so—within the medium of the lunar soil.
The seeds were then sown and irrigated. They were placed in ventilated boxes with growth lights. Within 48 to 60 hours, all of the seeds in all of the mini-pots began to germinate—but with very different results depending upon the soil used.
The best results came from the volcanic terrestrial soil. They had fast growth and healthy, broad leaves. However, the seeds planted in lunar soil produced a different result. All of the seeds did grow and they all grew well, but the overall effect was that the plants grew smaller and more slowly than the controls. Some of the leaves displayed black or red discoloration that was indicative of overall metabolic stress.
In general, Apollo 11 was the worst-performing plant, Apollo 12 followed, and Apollo 17 finally produced the best crop. Arabidopsis ThaianaAccording to researchers, this is because soil age plays a significant role in the development of earthworms. The older—or more mature—lunar regolith is, the longer it’s been exposed to cosmic energy and solar wind, and the greater the micrometeorite bombardment is that produces the glassy shards in the soil.
Apollo 11’s Sea of Tranquility site is older geologically speaking than Apollo 12’s Ocean of Storms soil, which experienced more-recent lava flows than Tranquility. And both are more mature than Apollo 17’s Taurus-Littrow site, a mountainous region whose surface was shaped by meteorite and asteroid bombardment more recently in geological time.
“What we found was that the regoliths that were more mature were indeed more toxic to the plants, or at least they presented a more toxic response,” said Paul.
This point was further supported by genetic research on plants. There are over 1,000 genes found in this genome Arabidopsis Thaianaactivated in order to aid the plant’s response to stress. The alien soil presented 465 genes that responded to the stresses in the Apollo 11 sample. The numbers for Apollos 12-17 were 235, 113 and 113. In other words, the thale cress’s DNA had to fight harder to adapt to the foreign soil gathered during the Apollo 11 mission. That’s bad news for future farming in the Sea of Tranquility, the Ocean of Storms, and even Taurus-Littrow, but potentially good news for future lunar crews overall.
“What we could simply do in the absence of other constraining factors, is land and establish a habitat on a lunar surface that is significantly younger than the Apollo 11, 12, and 17 sites,” said geologist and co-author Stephen Elardo. Elardo believes that immature flows of lava could be particularly beneficial to sites. “If you look at lava flow areas here on Earth—look at Hawaii for example, look at Iceland—those areas are quite green.”
This could mean that astronauts will be able to live on the moon in the future. Weir thinks so. “If you’re talking about a further future where you have actual lunar colonists, then I would say yes, because shipping food there is prohibitively expensive,” he says.
Although lunar agriculture is still in development, it must wait until the Artemis program can reach its goal of landing astronauts on the Moon by 2024. NASA’s best assurance of a successful mission to the moon will be made sometime during this decade. Once that promise is kept, this study brings future explorers one step closer to visiting the moon and calling it home.
Here are more must-read stories from TIME