Why Are Closed Systems Used In Space Farming

If humans want to survive long in space, or inhabit Mars, one of the most prominent steps would be learning or inventing new methods of growing plants in space. On Earth, we have favorable conditions like the presence of oxygen, sunlight, water, soil with nutrients, organic matter and microbes, optimum gravity, and other factors. But space is not so welcoming for living organisms. The ozone layer present in our stratosphere not only protects humans and animals from harmful radiations, but it also protects flora

In space, scientists are carrying out various experiments to grow plants inside the International Space Station. Till date, we have been able to grow three types of lettuce, Chinese cabbage, mizuna mustard, red Russian kale, and zinnia flowers in the Vegetable Production System, known as Veggie, in the ISS. But why grow them in a closed system? Why not in an open system?

Well, to know why, you should read these points.

Why Are Closed Systems Used In Space Farming

1. To Control Atmospheric Condition: Unlike Earth where favorable atmospheric condition is available to plants, in space we need to create them, or else maintain them. Closed system helps to maintain CO₂ levels, temperature and atmospheric pressure to support plant growth.

2. To Deliver Water and Nutrients in Microgravity: In low or zero-gravity conditions in space, water and air bulges form unpredictably, which can suffocate roots. In closed systems, hydroponics, aeroponics, or porous tubes are used to ensure roots receive both water and oxygen consistently.

3. To Prevent Gas Stratification: Unlike Earth, where air flows carry gases from one place to another, in space, O₂ builds up around leaves and CO₂ is depleted, which affects photosynthesis in plants. Growing plants in a closed system in space solves this problem.

4. To Regulate Temperature: The presence of atmosphere on Earth helps regulate temperature, but in space, there is no atmosphere. That’s why a closed system is required to provide the optimum temperature needed for the growth of the plant.

5. To Provide Adequate Light: In the absence of natural sunlight like on Earth, LEDs can be used in closed systems to provide light of specific wavelengths—mostly red (660 nm) and blue (450 nm)—which are the most efficient for photosynthesis.

6. To Prevent Contamination: Even on Earth, we’re not able to completely eradicate the possibility of contamination that could harm our environment. Therefore, growing plants in space can become a breeding ground for undesirable bacteria, fungi, etc. And with conditions so hostile, we can’t afford to let any mishap occur. In a closed system, scientists can easily eradicate or control any contamination.

7. To Recycle Waste: BLSS designs, like ESA’s MELiSSA, integrate microbial reactors, algae, and crops to recycle urine, feces, and CO₂ into oxygen and fertilizer in space. Hence, they solve the problem of waste recycling in space.

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