"It's hard to explore the galaxy on an empty stomach." That's not mine; that's a quote from a plant engineer and friend, which stuck with me. I found it amusing, the juxtaposition of the grandeur of deep space exploration with basic, mundane human needs. We can have the biggest, fastest rockets, but without a food production system, we won't go very far. So, what's our current progress on this?
Carte Du Jour
As the photo hints, astronauts are currently growing edible plants in space. Why experiment with plants? Mainly because of the difficulty to access fresh fruits and vegetables in space, their great nutritional value, and the potential of the gained knowledge to solve agricultural challenges on earth. So, on the menu we can find several kinds of leafy greens like lettuce and cabbage, bulbous plants like onions and garlic, species of wheat, and even herbs like dill and parsley.
Space Gardens
Space plants grow in space gardens. We are really doing our best to simulate a "garden" as we know it, without gravity as we know it. In these "controlled environment systems", as they are called, plants grow on pillows filled with clay and fertilizers. The pillow helps the water move around between the roots - otherwise, without gravity, it would just form a bubble, drowning some roots and being completely unreachable for other roots. Most plants need plenty of light, too, and LED lights are used to this end. Other important parameters, like temperature and moisture, are constantly measured and, if there is no video camera installed, pictures are being taken all the time.
Harvested Goods
One of the first rules of a laboratory is to never taste anything in a laboratory, and the ISS is basically a giant laboratory. Even though the plants grow in a controlled environment, we still need to make sure that they are 100% safe and there is no risk of food poisoning. Thus, there used to be a time when the harvest was ready, but for research purposes, not for eating purposes. Samples were being collected, frozen or chemically fixed, and sent back down to earth for tests. Now, thankfully, we have grown out of this phase! Astronauts can safely eat a variety of the plants they grow. However, they can only eat half of the harvest; the other half is still sent back down to earth, for more tests that will determine how being in space affects a plant's growth.
Body and Soul
Astronaut diets consist mainly of pre-packaged foods with an expiration date really far in the future. Such long shelf-life is achieved through processing which most of the times destroys essential vitamins, kills beneficial microorganisms, and introduces high amounts of salt in the food. Having a source of fresh produce can prevent nutritional deficiencies and bring some balance to the space diets.
On top of that, fresh produce can have a positive impact on mental health as well. Plants are reminiscent of life on Earth; their look, feel, and smell can keep a nostalgic astronaut happy and reduce their anxiety. Astronauts have reported that caring for a plant boosts their mood and productivity. And we shouldn't underestimate the escape plants offer from the "menu fatigue" experienced when one has to eat the same pre-packaged food over and over again.
Future Prospects
So, what would make a cool space garden even cooler? From a nutrition scientist's point of view, I'd want to see food that is fortified with vitamins and minerals. Yes, plants are already packed with these elements, but nutrient absorption in space is weird. Astronauts would be benefited from eating plants that have been modified to contain even more vitamin D, even more calcium, even more antioxidants.
Another thing we could do would be to break the space garden out of the constraints of the ISS. It could be part of a moon base, or a Mars base. It could be a little satellite that would support an entire community of space explorers.
But the ultimate upgrade, the epitome of innovation will be achieved once the food production is coupled with oxygen production and waste management. Such a closed-loop food production system will be a breakthrough, not only because it will be able to sustain space missions of multiple years, but also because it can find applications on earth! With many communities already struggling to secure enough food, and with climate change threatening to render even more areas of our earth infertile, there are many things to learn from a food production system that is based on recycling and reusing.