My Background
Hello! My name is Anthony Neil Tan and I am a UC Berkeley Bioengineering undergraduate. Last year, I competed in NASA's Growing Beyond Earth (GBE) maker contest with the goal of becoming a better engineer. 1 Meter of Pi is surprisingly similar to GBE, but this time around, 1 Meter of Pi is an individual challenge. I won't have engineering team members to fall back on, but instead I will have the opportunity to face challenges head-on and develop a newfound confidence in my engineering skills.
Entering this contest and being chosen as a sponsored challenger is a huge milestone for me, someone who always wanted to try out engineering projects in high school, but felt too daunted to start. As I progress through this challenge, I hope I can inspire fellow engineers to cast aside the fear of failure and pursue their interests with confidence in personal growth.
View my team’s winning GBE design here.
1 Meter Of Pi Design Challenge
The goal of this challenge is to design a microgravity-compatible plant growth chamber that uses 1m3 of space efficiently to maximize food production. Its purpose is to feed and nourish a rocket ship crew during a trip to Mars; the crew needs help ASAP so the design and working prototype must be completed within 10 weeks!
Based on the prompt, I will consider the following:
What factors are essential for plant growth and how are they influenced by microgravity?
How will my design produce enough food to feed and nourish the entire crew?
How will I design and build a functional prototype within 10 weeks?
How will I incorporate the kit so that the system is automated?
Available Technologies: NASA's Veggie
Researching available technologies is a great way to start a technical challenge. Chances are, a technology similar to the one I'm looking to create already exists. Lo and behold, I came across NASA's Veggie, shorthand for The Vegetable Production System. I found two insightful research papers: "Plant Pillow Preparation for the Veggie Plant Growth System on the International Space Station" and "VEG-01: Veggie Hardware Validation Testing on the International Space Station" (PDFs attached). The first research paper highlights the importance of containing the grow medium, fertilizer, and water as there is no gravity in outer space to anchor these elements. The second research paper describes the experimental results of Veggie aboard the International Space Station and suggests that automation of processes such as irrigation is the next logical step in developing robust plant growth chambers.
Outredgeous red romaine lettuce plants grow inside a prototype Veggie flight pillow.
Photo Credits: NASA/Dr. Gioia Massa
Now that we have a good understanding of available technologies, we can dive into the first consideration: What factors are essential for plant growth and how are they influenced by microgravity?
Five Factors Essential For Plant Growth
Having been gardening since I was four, I have a strong intuition of what goes into nurturing plants.. on Earth that is. Growing plants under microgravity conditions is a whole different game. So in this section, I'll methodically review the five factors essential for plant growth and I'll synthesize what I've learned from the NASA research papers to infer how these factors may change in outer space.
Light
Light provides plants with energy to grow. In microgravity conditions, directionality of plant growth is solely dictated by light since gravitropism, directionality according to gravity, is not present. Thus I can orient plants in any direction using light. I will use artificial lighting (i.e. LEDs) so I can develop customized light recipes and program optimal photoperiods (periods of light and darkness) for different plants.
Air
Plant leaves need carbon dioxide to perform photosynthesis. However, in microgravity there are no natural convection currents and air stagnates, causing plants to suffocate in bubbles of oxygen produced by photosynthesis. To circulate carbon dioxide to plant leaves, I will install a fan.
Plant roots need oxygen to perform cellular respiration. To ensure aeration in the roots, I will use calcined clay as the growing substrate. Calcined clay is very porous and absorbent, making it excellent at providing air and delivering water to the roots.
Temperature
In optimal temperatures, plants thrive and in suboptimal temperatures, plant growth is delayed or stunted. Rocket ships and spacecraft like the International Space Station have temperature-controlled environments in which plants can grow well so heating and cooling components are not necessary.
Nutrients
Plants need nutrients to grow. Since nutrient application is messy (especially in microgravity), nutrients should be applied prior to space travel. Slow release fertilizer can be mixed in with the growing substrate before rocket ship launch.
Water
Plants require water to grow. In microgravity, water can easily escape from the plant pot and can be messy when applied so it is important to design self-contained pots which can be easily injected with water.
In the next blog, I'll introduce my design: The Space Salad System! Until then, keep learning and have fun! Click the arrow to navigate to the next blog.
 | Plant_Pillow_Preparation_for_the_Veggie_Plant_Grow.pdf |
 | VEG-01_Veggie_Hardware_Validation_Testing_on_the_I.pdf |
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