Agriculture is an essential part of our daily lives, whether we’re directly involved with it or not. It is what provides us food, nutrients, and nourishment, and is crucial to our survival. But what happens when you take a human who is not on Earth, and instead on either a long journey to another planet or just on another celestial body. We then need to start looking into agriculture in space, or in other words, space farming.
Space farming is described as the plants but not on Earth, meaning either in outer space itself or on another celestial body. As I mentioned before, it is important to explore this topic since we’re slowly approaching an era of a lot of deep space exploration. These crewed missions will definitely need to utilize space farming in order to have an efficient and affordable energy source.
Why is this important? Well, let’s look at the facts. Resupply missions can be expensive, and will only cost more when sending them to another planet, and in addition, takes a lot of time. NASA says that each meal for an astronaut on the International Space Station (ISS) weighs about 2 pounds, including packaging. 3 meals a day equals 6 pounds. Now for a 6 month ISS mission, that’s about 1100 pounds for just one person. Now, let’s consider a 2.5 crewed Mars mission with 4 people. That number now becomes almost 15,000 pounds or 6800 kg, and this isn’t even including the extras that NASA would include in the mission. This is why we need to consider astronauts producing their own crops on the spaceship or at the destination itself.
Space farming can also provide both physiological and psychological benefits. Having astronauts eat freshly grown crops instead of the freeze-dried food they constantly eat currently on the ISS would help with them getting all the necessary nutrients they might have been missing. Also, it is known that plants and gardening help improve one’s mood and relieves stress and anxiety. This is important, especially during a deep space mission, because it is keeping up the morale on the mission.
So, what is exactly involved in space farming? What are the challenges we face? It is thought that a space farm would be extremely efficient and also sustainable since it would utilize recycled materials, mainly due to its limiting environment. One of the first limitations that need to be overcome is being in an environment of either lower gravity or microgravity. Plants have a direct response to the gravitational pull here on Earth called gravitropism. It affects root growth and stem orientation, which are both essential to general plant growth.
Something else to consider is that plants in space can suffer from waterlogging. On Earth when we water plants, it usually would trickle down into the coil and towards the roots. But in microgravity at least, water will encase the roots and form just a huge bubble, and this can actually kill the plant. To combat this, scientists have experimented with using some sort of special porous clay instead of regular soil.
Lastly, seeds produced in different gravities can lead to different nutritional value compared to ones produced here on Earth, which can definitely throw off some of the plants being grown. So yeah, gravity is a huge factor to consider when thinking about space agriculture.
The next issue is dealing with artificial lighting, which is more of an issue on space station farming than it is on lunar or martian farming. Scientists have to basically figure out how to trick plants into using this artificial lighting like it would sunlight. We need efficient lightbulbs that don’t produce excessive amounts of heat that would later need to be accounted for, and also wouldn’t add much to the weight of a mission. Light-emitting diodes (LEDs) are a solution to this issue. The lighting would also be responsible for establishing day-night cycles for plants like how it exists here on Earth.
These plants that are being grown also have more to offer than just a food source, and that is air filtration. Crops would be utilizing CO2 from our air and produce oxygen, meaning astronauts would be able to have nice fresh breathable air while these crops filter out the CO2. Giant greenhouses could provide thousands of pounds of air in a given year.
Now, let’s discuss specific instances of space farming, first on the ISS. The ISS has sone numerous experiments regarding agriculture, not only helping with Earth with it but also learning how to do it in space. The research being done on the space station will be crucial for future deep space exploration missions. In 2015, astronauts made history by eating food grown in space, specifically red romaine lettuce. Let’s talk about some of the current experiments happening on the ISS:
The Plant Habitat-01 experiment has the goal of learning more about the gravitational effects on plants in microgravity and will be looking at growing large plants in a controlled environment. It utilizes the Advanced Plant Habitat on the ISS.
The VEG-03G experiment is dedicated to learning more growing pick-and-eat plants such as lettuce and cabbage. The experiment is also trying to learn more about the effects of microgravity on these plants and sends them back to Earth for testing. It utilizes the VEGGIE instrument on the ISS.
Onto space farming on celestial bodies. All space farming done on these bodies would have to occur in domes that have some form of regulation. Scientists and engineers could definitely get creative with how exactly we regulate the domes. For example, certain domes can represent different seasons, meaning that they would each have specific conditions permanently set in each of them for the plants. Now, let’s move on to specific celestial bodies, aka the main ones in question, the Moon and Mars.
There have been many proposed methods of having a space farm on the moon, and it will most likely be the first body that is not Earth to have farming done on it. It is thought that a farm at the poles of the moon would make the most sense. Since there is water trapped inside some of the craters, it can be utilized for the plants that astronauts would be growing. It is also thought that burying these farms could help with protection from radiation and micrometeorites that could damage the domes.
Next, let’s talk about Mars, the true prime candidate for space farming. It is the most talked about since missions to the red planet will be extremely long, and once on the surface, understanding how to utilize the Martian soil will be important.
Many people see Mars as a completely dead planet where no life can grow whatsoever, and while that may be partially true, it isn’t for agriculture. The Martian soil actually contains a majority of the necessary macronutrients and micronutrients needed for successful farming. The issue is that it doesn’t have the necessary biological components, which is where humans and outside materials will need to come into play. Martian soil also contains a type of salt called perchlorate that is hazardous to the human body and can also inhibit plant growth. Turns out though that you can just wash these salts out, and things should be fine.
There are also many other concepts of growing plants on Mars that doesn’t involve using its soil, including hydroponics or aeroponics, but this would take more money, time, and infrastructure. This is why we’re focused on agriculture, and not new technologies that will take too much effort to develop (maybe for the future though).
An additional issue that comes with growing plants on Mars is the low-pressure environment caused by the thin Martian atmosphere. This can lead to issues with photosynthesis and evapotranspiration, but it has been observed that high levels of CO2 can mitigate this issue.
What other research has been done on all of this? A lot actually. There was a research group in the Netherlands that actually did a study on growing different plants in earth soil, lunar soil, and martian soil, the latter two being simulated versions. They were mainly testing out what a second-generation crop cycle grown on the Moon or Mars would look like, and they did this by collecting organic material (cut up ryegrass) from a past cycle, and introduced them into these regoliths. They found that the total biomass produced was similar in the Earth and Martian soils, but was slightly lower for the lunar soil, meaning extra steps would need to be taken.
There was another study that did an analysis of feeding a Martian colony of 1 million people, giving us insight on how feasible all of this space farming is. Unfortunately, it turns out that the colony would heavily rely on Earth resupply missions for around a century, and then after that would it be self-sustaining through its own farming.
Nonetheless, the idea of eating food entirely grown in space sounds like something I myself would definitely be first in line for. How about you?