If future residents of Mars have to choose between beer or cannabis, which is easier to grow in space?
That's one of many questions considered by the Mars Farm Odyssey, a group of urban farmers, food entrepreneurs, bio-hackers, and others who want to figure out how space farming should work.
Shipping food to Mars could cost nearly $1 billion per person per year—so if people want to live there, growing food on the planet is a necessary step.
It's a challenge that NASA, the European Space Agency, and others are working on. But Mars Farms thinks that its own scientists, engineers, and entrepreneurs—focused on vertical farming on Earth—can also play a role in finding solutions.
"The collective hive of humanity has more ideas to offer than a research team buried in a bunker somewhere," says Karin Kloosterman, cofounder of Flux, a startup currently developing a plant-monitoring device for urban farmers. "And this know-how can be applied on Earth, too, so young researchers can employ the hive to start experimentation even without the gravity or resource limitations one would experience in space."
In a recent meeting in Tel Aviv, Mars Farm debated some of the details of space farming. One workshop focused on developing a citizen science kit that will crowdsource how particular plants grow, making it possible to build controlled "food computers" that robotically recreate the climate and nutrients that a crop needs.
"With a complete model of the plant, and knowledge of these environmental factors (pH of the water, temperature, relative humidity, etc.) you would be able to predict the growth of a plant, and also steer the growth," says Thieme Hennis, an Amsterdam-based researcher and designer who came to the meeting.
A food computer could help precisely recreate the flavors people expect from Earth. "We could grow strawberries that taste like the ones you had at home as a child," says Kloosterman.
While NASA is developing Mars food bars, the group in Tel Aviv concluded that nutrition bars aren't a long-term solution.
"We debated how this is no way to live," Kloosterman says. "That food must fit humanity. It must evoke passions, our creativity, and our senses." (NASA is also testing growing space crops, and successfully raised lettuce on the International Space Station in 2015.)
Growing a diversity of crops using food computers will require massive data storage. "It's not only about the plants but a complex interaction and array of biochemical signals between individuals and other organisms such as other plants and bacteria, fish, and shrimp," she says.
While growing food in a hydroponic greenhouse on Mars might bear some resemblance to vertical farming in a city on Earth, there are challenges: Mars gets about half the sunlight of Earth, the gravity is much lower, and though there's water on the planet, it might not be drinkable.
"My guess is that Mars, because there is at least some gravity, would be suitable to grow in a similar way we do here on Earth in controlled closed-loop systems," says Hennis. "Everything will be controlled, but where here on Earth we get rid of the disposable waste/biomass, the conditions in space are such that you don't want to rely on external input—hence all must be recycled and reused."
When the group debated the merits of whether beer or cannabis should be the preferred intoxicant on Mars at the recent meeting in Tel Aviv, they landed on cannabis, though they also agreed that it would be possible to use recycling to make a little beer.
"We'd let a small craft beer system on board and we'd make beer from recycled urine, but cannabis is, by far, getting the first vote by me," says Kloosterman.
A European Space Agency consortium called MELiSSA (The Micro-Ecological Life Support System Alternative) is developing closed-loop systems that can recycle plant waste, urine, CO2, and other waste to keep a greenhouse running. "It's a holistic approach toward living in space, not just surviving in space," says Hennis, who is part of a group collaborating with MELiSSA.
All of this could also be useful on an increasingly resource-constrained Earth. "The most important reason for us to be involved is that space farming is a perfect lens toward sustainability on our planet," says Hennis. "Ultimately, you need to [re]create a completely closed-loop system, with solar energy as the only external output. We're not seeking refuge and preparing for that—we're exploring, and by doing that facilitating new solutions for the food crisis on Earth."