Food made from asteroids may help future astronauts live in space for years without supplies from Earth, according to research from Western University’s Institute for Earth and Space Exploration.
With help from a DARPA-funded process that uses bacteria to turn plastic waste into food, Western University (WU) researchers say the process could theoretically support hundreds or even thousands of astronauts for a year.
The researchers note that the process has challenges, including the sheer volume of asteroid material needed to generate enough edible biomass. However, they believe their study shows that making food from space rocks is a potentially viable solution to feeding astronauts on deep space missions or colonists living on Mars.
“What if humanity could acquire the raw materials to make food in space?” the study authors write. “This article investigates ways to do just that using new techniques developed to recycle plastic waste into food on Earth and extrapolating these techniques to the theoretical application of converting asteroidal material into food.”
Food Made From Asteroids Contains Valuable Nutritional Profile
In a series of experiments, the WU research team fed organic material similar to material found on asteroids to a strain of bacteria designed to use it for food. As expected, the bacteria consumed the material, growing into a significant biomass. According to the study’s lead researcher, Joshua Pierce, the team’s newly grown biomass had the texture and appearance of a caramel milkshake.
After harvesting the biomass, the team sent it to Eurofins Food Chemistry Testing Madison, Inc., for a nutritional analysis. The results showed that the organic, edible biomass contained roughly 45% carbohydrates, 35% of which were dietary fiber, 15% fat, 32% protein, 7% ash, and 1% moisture. Although not a perfectly balanced ratio, humans eating the 2,500 calories per day used in NASA calculations could survive on this nutritional profile.
The study authors point out that if humans want to explore the depths of the solar system and beyond, “it will be necessary to become less reliant on the resupply tether to Earth.”
For example, they explain that sending enough food to Mars for six astronauts on a one-year mission will weigh around 12 tons “without packaging.” For colonists looking to set up a permanent settlement on Mars or someplace else in the solar system, the need for food independence from Earth only increases.
Since humans need variety in their diet, the team explored altering the biomass to create more palatable alternatives. One test resulted in a yogurt-like substance that could be mixed with flavorings or seasonings. Attempts to dry out the biomass resulted in a nutrient-dense powder that could be used in various culinary applications.
Bennu-Sized Asteroid Could Feed 17,000 Astronauts for a Year
Although the team’s lab results were promising, the researchers say they were forced to use a simulated asteroid instead of a real one. They made some overtures to space rock owners to see if they could use them to make food out of asteroids. However, since the process destroys the asteroid, Pearce said, “The people that collect rocks were not happy when we made these proposals.”
Fortunately, Pearce says that the hydrocarbons and other organic molecules found in asteroids “matches up pretty reasonably” with the products we already know the bacteria used in the experiments can eat. The team says a wide range of hydrocarbons and other organic compounds found in asteroids could affect the amount available for the bacteria to convert to edible biomass.
In this study, the team looked at two forms of organic material found in asteroids, Bennu and the Murchison meteorite. The most readily available compounds were aliphatic hydrocarbons, setting a mathematical “floor” for the amount of food made of asteroids a rock like Murchison could generate.
The second and most prevalent carbon molecule found in these types of asteroids is solvent-insoluble organic matter (IOM). In theory, the researchers say that the combination of aliphatic compounds and IONs represents “the maximum amount of organic matter that could theoretically be attributed to food production.”
After doing some calculations, the team found a wide range of food production capabilities depending on how much carbon material in the asteroids can be accessed “assuming NASA’s standard diet of 2500 calories per day is maintained.”
When only the aliphatic hydrocarbons can be converted, the team found that an asteroid the size of Bennu could support around 600 astronauts for one year. However, if the process could convert all of the carbon, a Bennu-sized space rock could support around 17,000 astronauts over that same amount of time.
“The average results for the minimum scenario (only aliphatic hydrocarbons are converted into biomass) is over 631 astronaut life years, and the average results for the maximum scenario (all IOM are converted into biomass) is over 17 000 astronaut life years,” the study authors write.
A Path For Human Space Exploration
In the study’s conclusion, the authors highlight several challenges to creating food made from asteroids. For example, Pearce said that future space explorers would need a “super machine” designed to break down the asteroid rock and manage the growth of the bacteria efficiently.
Scaling the process is also a significant barrier; smaller missions may manage this better than larger ones. However, large, permanent settlements like those planned for the Moon and Mars would require industrial-scale facilities to produce enough food made from asteroids to support thousands of humans without resupply missions from Earth.
“The values obtained for the amount of asteroid mass that need to be processed to provide food for a single astronaut are large, but if human exploration of the solar system is to be done, it provides a potential path to doing so,” the study authors write. “Based on the results of this study, this approach appears promising but there are substantial areas of future work.”
The study “How we can mine asteroids for space food” was published in the International Journal of Astrobiology.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.