Solar-Powered Autonomous Greenhouse Could Produce Fresh Spinach On Mars
As plans for a Mars colony are underway, at least preliminarily and tentatively, scores of questions arise about the logistics of supporting such a colony. Will people live under a dome? (Yes, until/unless we terraform Mars) What about radiation? And, most importantly, what will the Mars colonists have for dinner?
The answer: spinach.
A team from Greece recently won NASA’s Deployable Greenhouse Space Apps challenge. The challenge was for teams to design a deployable greenhouse small and light enough to stow aboard a spacecraft, that would require as few resources as possible, could function at low pressure, and could store plant-generated oxygen. Ideally, the greenhouse would also have a growing system, a system for recycling water, and a thermal control system.
The winning greenhouse, called “Popeye on Mars,” has an aeroponic system that can operate autonomously for 45 days, which is all the time needed for it to produce spinach. It can stabilize its internal environment, store oxygen, and harvest the spinach at the end of the 45-day cycle. It’s powered by photovoltaic panels that convert that pesky solar radiation into electricity via semiconductors, and is protected against the extreme conditions on the red planet.
The question of how to feed astronauts isn’t a new one. The tubes, packets, and pouches previously used won’t provide enough sustenance to avoid serious muscle loss, so one of the practical problems of colonizing Mars or any other planet is to figure out a stable food source that will help mitigate the muscle and weight loss typically experienced by astronauts. Earlier this year, scientists undertook a four-month simulated Mars mission where they experimented with possible long-term foods. Since there’s some gravity on Mars, it’s possible that astronauts could cook basic grains, but over time they’d miss their veggies. The “Popeye on Mars” greenhouse would provide some much-needed leafy greens.
The greenhouse is designed to be sent ahead of human colonists, and deploy into a dome near Mars’ equator. It has a cover that opens during the day, allowing the photovoltaic panels to harness solar energy. By using solar energy and the relatively mild weather conditions near the equator, it could begin the autonomous process of aeroponically growing the spinach plants. The circular dome has a diameter of roughly three meters, and could produce a healthy spinach crop in 45 days. The greenhouse could continue functioning for up to 65 days if the plants need more time. After that, the stored oxygen and the seeds from the plants need to be collected. After performing relatively simple maintenance on the dome and planting the next patch of seeds, the greenhouse would begin the next cycle.
If growing spinach in a deployable greenhouse sounds more fun than growing it in your garden, you could check out the source code and make your own dome. Or you could just stop by the supermarket and grab some spinach. Just remember that while canned spinach might have worked for Popeye, surely colonists on the Red Planet deserve better.