Mark Watney’s unflinching determination to survive on Mars and NASA’s dramatic rescue plan to bring him home kept us all on the edge of our seats throughout the movie. When a massive dust storm engulfs the Ares III’s MAV, the crew is forced to evacuate without Watney (who is presumably dead after being struck by the storm). However, Watney not only survives the storm but also Mars’ inhabitable atmosphere through Science (and fiction).
What stands out the most throughout the film is this botanist’s potato farm inside the Hab. He fertilizes the soil with the crew’s bio-waste and manufactures water from leftover rocket fuel. Using slices of previously grown potatoes and his faeces, he manages to generate a stock to last for hundreds of days. While the plot can be lauded for being artistically unique, scientifically we can raise many questions. In reality, the Mars ‘soil mixture’ he made doesn’t have the complex food web of microbes that we have on Earth. Further, what about the pathogens in human faeces? What about perchlorates in Mars’ soil? Moreover, recycling of nutrients between soil and plants and atmosphere can be difficult to control owing to Mars’ extreme condition with respect to soil, water, gravity and weather. Could the faecal bacteria even thrive on Mars? Not to forget the array of solar energy particles and galactic cosmic rays on the surface of Mars…
So where are we now? A lot of research is focused on space farming. Researchers have tried simulating Lunar and Martian regolith, by mixing it with organic matter to mimic the addition of residues of previous harvests. Not only did 9 out of 10 species grow, it was also possible to harvest edible parts of these samples. Seeds from these were then germinated to further experiment with self-sustainability.
Yet another option is hydroponics but the inert material will have to be replaced after every few cycles. There is also aeroponics (a plant-cultivation technique in which the roots hang suspended in the air while nutrient solution is delivered to them in the form of a fine mist). Optimizing nutrient delivery methods in different gravitational settings is the challenge with this method. NASA has been testing and improving its inflatable low-mass aeroponic system for use in space stations since over two decades now. Vertical farming, along with aeroponics, also seems a promising combination. Vertical farming, an indoor agriculture setup, is where crops are cultivated in stacked systems with lighting, water and nutrient sources controlled by artificial intelligence.
A recently published paper(Shannon N. Nangle et al., 2021) outlines stepwise integration of Biotechnology to address problems concerning settlement on Mars. To summarize their study, they focused on food, materials, therapeutics and waste reclamation. From testing food production strategies, production of bio-based polymers from carbon dioxide, evaluating systems for water stream with transient crew in Stage 0 to large scale production of crops, pharmaceuticals and therapeutics with more than 10,000 people: this paper is a must read.
To conclude, while we do not know when we can start growing potatoes on the red planet, we do know this isn’t exactly a sci-fi plot after all.