Our vision for farming in space was well received by people at the Mars City Design competition; they were already dedicated to achieving space settlement. However, we recently spoke at an urban farming forum in Ireland where we found that some people are very incredulous about whether geeking out on all this space stuff is a good use of time and resources. A lot of Irish people that we spoke with expressed that they saw space exploration as merely a remnant of Cold War muscle flexing and doesn’t really serve any useful purpose to humanity. These people questioned whether it is wise to invest public funds into space exploration projects. They look at Mars and think:
“There can’t be anything for us in space. Look at the conditions compared to Earth: Mars is a hostile wasteland and where we live is already immediately habitable. Besides, there are a lot of problems on Earth that need to be addressed first. Our energy and resources should be directed towards improving conditions here, rather than wasted trying to figure out how to colonize other planets.”
I can see the validity in this argument. Indeed, space exploration is an extremely costly endeavor that currently yields no immediate benefits, beyond the philosophical joy of knowing that humans have accomplished something incredible. Currently, colonization of Mars will only be beneficial to future generations and this type of risk taking for the sake of potential altruism doesn’t really resonate with a lot of people. If we are to enlist the support of people with this point of view, we need to prove that research directed at space exploration has additional applications that are immediately beneficial to humanity. Fortunately, this research happens to be very applicable for resource conservation and sustainable agricultural issues facing humanity today.
Resource conservation is obviously a very fraught topic. It has been an uphill battle to get business and government on board for this much needed paradigm shift. This is where space colonization motivates us. The technology needed to survive and adapt to climate change is deeply lacking in funding and respect. However, space exploration is sexy and exciting. If people aren’t motivated by stewardship of their planet, then maybe we can motivate them to achieve conservation by harnessing the very powerful human drive for expansion. We can use the discoveries geared towards space exploration to inspire sustainable practices here on Earth.
Attempting to solve problems for closed-loop systems like a space station allows us to rethink conservation in a way that has not been necessary in our resource-rich past. By removing the idea that unlimited inputs from the Earth’s natural resources is a given, this forces us to design our food systems in a resource conservative manner.
In response to those who think that trying to get to Mars is a waste of energy, let me say this: think of how much better we will need to be at conserving energy to even get there. The constraints of living on a space station will force us to develop methods for extreme energy and resource conservation, and these techniques will undoubtedly have application on Earth as we inch closer to the end of the fossil fuel era.
Recently Galactic Farms won the agricultural award at the Mars City Design competition for our submission inspired by Cyprien Verseux, a PhD student from the University of Rome. Under the guidance of Daniela Billi, Verseux published a review paper in the International Journal of Astrobiology that describes how it may be possible to grow cyanobacteria on Mars, using Martian regolith (i.e. undeveloped soil) as a substrate. For our submission to the competition, we supposed that it may be possible to use the cyanobacteria biomass as a nitrogen source, much like manure is used in compost for generating a soil-like substrate.
Although technically bacteria, cyanobacteria are effectively similar to plants in their ecological role: they are what ecologists call producers. This means that rather than needing to find something living to eat, like all animals do, producers are able to eat non-living minerals and gases and convert them into a biomass that can be eaten by other organisms.
They transform non-living matter into complex molecules that are a part of a living organism that exists within a food chain, and that within an ecosystem. Producers use energy obtained from the sun to power their nutrient extraction and bioaccumulation from non-living matter in their environment.
Species of cyanobacteria, like Spirulina, are special because they not only sequester carbon dioxide from the atmosphere through photosynthesis (like all plants do), but they are also able to sequester atmospheric nitrogen as well. When nitrogen is converted from the atmospheric form into the form found in biomass, it is called fixed nitrogen. In nature, there are very few organisms that are able to take nitrogen from the atmosphere and fix it into a living biomass. There are bacteria that live in the little root nodules of legumes (e.g. beans) that are able to fix nitrogen, but they can not be cultured as easily as cyanobacteria.
Fixed nitrogen is very important because this is the form that plants can uptake and convert into protein. The biomass generated by this method could potentially be used as a food source directly, for example the cyanobacteria species Spirulina is used worldwide as a complete protein source in survival situations.
But rather than eating the cyanobacteria directly, we hypothesized that the nitrogen rich cyanobacteria biomass could be used instead to develop a soil-like substrate for growing higher plants. By capturing these materials in a cyanobacteria biomass, nutrients in the Martian regolith that were less available to plants could be microbially converted into a form that can be made available to a wide variety of crops.
Using traditional composting practices that require the addition of a carbon source, the cyanobacteria biomass could be digested microbially, releasing minerals into a bioavailable form. These nutrients would be converted into a soil-like substrate can be used to grow higher plants for human consumption.
Alternatively, this soil-like substrate could then be leached of those plant nutrients using pH adjusted water to create a hydroponic nutrient solution that could be used to grow food crops for Martian colonists. At Galactic Farms, we have been able to grow leafy greens and culinary herbs using a method very similar to the one described in our competition submission.
The missing piece of the puzzle, however, is finding a species of cyanobacteria that not only does well under reduced gravity conditions like on Mars, but also accumulates minerals in ratios that are conducive to plant growth. For example, Spirulina may be a good candidate as a nutrient source for humans, but it would make a poor substrate for higher plants. This is because the species Spirulina accumulates the sodium chloride salt at levels that inhibit the growth of higher plants.
How quickly the sodium chloride levels accumulate to inhibitory levels depends on the mineral composition of the regolith and whether astronaut urine is used as a supplemental mineral source. Currently, there are no known methods for removing sodium chloride salt without also removing other important minerals that are necessary for plant growth. To accomplish our goal, we instead must find a species of nitrogen fixing cyanobacteria that does not accumulate sodium chloride at inhibitory levels.
At Galactic Farms, we have been inspired by research in the field of agricultural engineering for applications in space exploration. For our submission to the Mars City Design competition, we took what the scientific community knows about culturing cyanobacteria on Martian-like substrate and ran with it. We imagined a way to incorporate known methods with a technique we have used to produce leafy greens and culinary herbs indoors using controlled environment agriculture methods. We are currently designing an experiment to test our hypothesis put forth during the Mars City Design Competition. Keep checking in for updates as we explore this topic.
Hexgardens in a Harsh Environment
After several years of working with experimental aquaponic systems, including the SPACE 200 and the Hi-SEAS X-30 systems, we began plans to build a system scaled to production volumes. To better understand the logistics for growing off-season produce in our region, we built a small demonstration system in our home shop. Our shop space has a fairly small footprint (12’ x 12’) with high ceilings (13’).
To capitalize on our headspace, we built the system to suspend from the ceiling which allowed us to conserve floor space for seed starting. Although this allowed us to make the most of the floor space, it turned out to be a dangerous and tedious arrangement for managing plants. To check on our crops, we had to climb a very tall ladder to see them and then climb down to move the ladder to check the next tower over. Although we saved space by building high, we were wasting a lot of time and energy due to inaccessibility, not to mention the safety risks involved with working on a ladder so often.
To solve this problem, Jeff implemented a winch system that raises and lowers the towers when we need check on the plants. There are still some balance issues to work out with the winch, which becomes messy when the rows are full of water. Perhaps we should have hung the towers at eye level from the beginning, but hopefully our mistakes will inform future developments.
We had some really interesting results with our Zero-G system. Basil grew quite well and definitely has potential for commercial production. Herbs are generally thought to do poorly in controlled environment systems. This is usually because the environment is too accommodating to induce the stresses required to stimulate essential oil production in herbs. Nonetheless, we were able to grow some very fragrant rosemary, basil and lavender. Perhaps the frequency of our LED lights helped stimulate essential oil production.
We also grew a few varieties of leafy greens, but they exhibited a very strange growth pattern of elongated nodes. I have read that this growth pattern occurs in soybeans when there is a non-ideal ratio of red to far red light used. The article stated that a certain threshold of blue light can remedy this problem. The next time we grow leafy greens I will try using a more complete spectrum. The leafy greens also had heavy issues with whiteflies and aphids. We didn’t see any insects on the herbs, probably because their essential oil production acted as a herbivore deterrence.
We shut the system down at the end of the winter when we started to focus our attention on outdoor crops. If we were to reboot the Zero-G, I would definitely want to adjust the aforementioned issues. But the most important change I would want to implement is USDA compliance practices so that we can feel more confident about the safety of the food we are producing.
We learned a lot and collected a lot of really great data with the Zero-G experimental system. We considered applying for the Growth Through Agriculture grant again this year, but when I was writing our proposal for a container sized production facility, I kept waking up in the middle of the night with a voice saying “Don’t do this!” After some soul searching, Jeff and I realized that we don’t necessarily want our lives to be about large scale crop production. We love to research, experiment and create. We decided to shift our focus and continue to experiment with controlled environment agriculture while sharing our experiences with the world.