As mankind looks to the vastness of the universe, the key challenge is how to grow plants sustainably in a space environment. In the weightless space of the universe, water is no longer bound by gravity, and traditional irrigation methods are completely ineffective - water droplets float around, plant roots have difficulty in capturing water, and may even be covered by a film of water leading to root rot due to lack of oxygen.
This problem not only threatens the food supply of astronauts but also affects the life support system of long-term space missions. To break through this bottleneck, technological innovation must address three core issues:
1. Uncontrolled and wasted water resources under weightlessness
On Earth, gravity allows water to naturally seep into the soil and be absorbed by plant roots. However, in a space capsule or space station, water is randomly dispersed in the form of suspended droplets and cannot be transported to plant roots in a directional manner. With traditional watering methods, not only is the water utilisation rate extremely low, but the floating droplets can also damage delicate equipment. More seriously, the plant root system is in the extreme state of ‘alternating wet and dry’ for a long time, which will directly lead to crop yield reduction or even death.
2. The fatal threat of liquid water film to the root system
Under the weightless environment, the excess water film attached to the surface of the root system can not be discharged, will form a barrier to isolate the oxygen, this ‘drowning root effect’ makes the plant in space than the earth environment is more likely to rot the root phenomenon.NASA's public report shows that in the international space station VEGGIE project between 2014-2019 years of a number of lettuce NASA public reports show that in many lettuce growing experiments on the VEGGIE project on the International Space Station between 2014 and 2019, root rot occurred in 47 per cent of cases (compared to 12 per cent in similar hydroponic systems on Earth) due to a thick film of water on the roots.
3. Closed ecosystems have very low tolerance for error
Space growing systems must achieve a resource recycling rate of over 98%, which means that every drop of water needs to be precisely controlled. Traditional microgravity irrigation programmes rely on complex piping and pumping systems, but equipment failure can lead to the collapse of the entire ecological module.
With the advancement of deep space exploration, ultrasonic atomizing technology may reshape mankind's perception of space agriculture. Perhaps one day, when astronauts pick fresh strawberries at an alien base, we will not only see the resilience of life condensed in these fruits, but also the wisdom of mankind to redefine nature with technology.
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