Introduction: Astronaut's Garden
This is an entry in Phase I of the Growing Beyond Earth maker contest, and as a freshman in high school I'm entering in the High School category. This was a one-person project.
I am incredibly excited to have this be my first Instructable.
This has been my first real engineering project, so there are a bunch of things I could have done better, or more efficiently looking back. However, I hope you'll forgive my lack of experience.
I have designed and started to build an aeroponics system, specially modified to grow plants in a microgravity and maximize space as much as possible to grow more veggies. For any earthlings, you could easily modify this so you can aeroponically grow your own plants.
As per the competition's guidelines, this system fits within a 50x50cm cube, provides the plants with nutrient water, fresh air, and light, and also maximizes the space in the cube so there is hardly ever any unused space.
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Step 1: Introduction
Before we get into the main bits of this Instructable, there are a few key things you need to know.
First, what is an aeroponics system? Well, it's a way of growing plants that requires no dirt. It's similar to hydroponics in that the nutrients that plants need to live is distributed through water, but aeroponics differs from hydroponics in that it is distributed through mist. This is why it's one of the most feasible ways to grow plants in space.
Secondly, I chose to only have 2 growing surfaces for its efficiency and simplicity. When growing on opposite sides of a cube, plants can cover the entire 50cm surface on both ends, and not have to compete for light from plants growing at different angles. No plants get stuck in the corner, per se. The plants don't have to compete to grow.
Step 2: Adaptability Is Key
The Astronaut's Garden fits inside of a 50x50 cm cube.
What makes it unique is that it maximizes space that the plants occupy ranging from when they start to sprout to when they are ready to harvest.
It has the potential to grow anything from micro greens that take up very little vertical space, to large heads of lettuce, that can grow 48 cm high. No one wants to eat the same vegetable over and over again (especially if that vegetable happens to be Brussels sprouts). This design allows for plants of all sizes, because the height of the chamber is adjustable, and so is the plant spacing because my design does not limit seed spacing to growing cups or pods.
The two features that allow such options are the fiber growing mat, and the adjustable LEDs.
Step 3: The LED Platform
This component of my design is what truly maximizes the growing space. In microgravity, plants will grow towards the light. There is no upside down or right-side up.
So while the current plant chambers of the ISS have plants growing on the 'bottom' and grow lights at the 'top', my design has plants growing on the 'top' and 'bottom' with grow lights in the middle.
Plants are growing on both ends towards the light, but in order to maximize the grow space, the level and position of the lights has to be adjusted.
For example, on one end you have some 3-day-old seedlings, taking up only a few centimeters of vertical space. Well that means the LEDs can also be a few centimeters away from the grow bed. On the other end, you can have some mature plants taking up 20 cm of space and the lights will need to be over 20 cm away. Because the lights are in the middle and the plants on either end, you can fit two crops into a 50cm cube and yield twice the vegetables.
Furthermore, if you were to use programmable LEDs, you could adjust the light frequencies on either side. Certain plants prefer certain wavelengths to use for photosynthesis, and that will allow the plants to grow more efficiently and faster.
I'd also like to add that the process of adjusting the height of the LED panel can also be automated. There's a lot of science that shows it can be beneficial for people's mental health to be around plants, but if the astronauts are busy, it can be a programed task. Using belts that move along a y-axis the LEDs can be moved up and down with a motor and some code.
Step 4: Growing Bed
I refer to the medium on which the plants will grow as a 'grow bed'. In my design, the grow bed is a simple piece of flat medium.
So, putting stuff into space is expensive. Really, really expensive. That's just one reason why growing food in space makes so much sense. It's cheeper, yummier, and more sustainable for long voyages. So, to lessen the weight of the payload, my design has the seeds and growing medium both packaged together.
Most aeroponics systems use either grow cups or another growing medium, and you can poke the seeds into the medium so they start growing there. It's easy enough on Earth, but in microgravity it could be time consuming and difficult to keep seeds from floating away.
Instead, if the seeds are sandwiched in-between layers of the growing medium or in-between the fibers, then the seeds would be pre-measured and ready to go. It's almost like if they got 'baked into the pancake batter of the growing medium'. All the astronauts would have to do is put in the growing medium, and it would get hydrated with the aeroponic mist.
I got this idea from a craft I did in elementary school, where you'd dunk paper towels into a mix of cornstarch and water, and lay seeds out on it. You'd fold the paper towel over the seeds creating a little burrito that you'd dry out, and in spring could plant it in your garden. It was easy and simple to plant it in the spring because you didn't have to worry about spacing the seeds out evenly, because the paper would decompose and the seeds were already spaced out neatly.
This same concept could be translated to the grow beds. Putting the seeds in a nutrient-rich medium, and dehydrating it so that the seeds were preserved and the grow medium becomes very light and thin. It makes the whole process of starting seedlings much more time-efficient, accurate, and measurable than if the whole thing had to be done by astronauts themselves.
Although as a student I have no way of implementing this within a few months for this contest, I hope that Fairchild and NASA will take it into consideration.
Step 5: The Basic Components
12 Volt Fan: I bought this online, and it will serve as air circulation. In a microgravity, if the air isn't constantly being circulated, then gasses will start to coalesce into 'bubbles'. Since the photosynthetic process takes in CO2 and gives off oxygen, it's important that the air keeps moving, and that fresh air is provided to the plants
Water Bladder: Using a water bladder (like the ones used in camelbacks) means that the Garden doesn't have to be hooked up to pipes. The bladder can be filled at a potable water station, have nutrient concentration added to it, and then connected to the pump.
Pump: Ideally, aeroponics systems use high-pressure pumps, because they can make water droplets the ideal size for plant root systems to absorb. However, they're really expensive.
Tube System: This connects to the pump and water bladder. It turns the water into a fine mist in the root chamber where the plant roots absorb it.
Step 6: Conclusion
Looking back, I've learned much much more than I expected to. I developed a bunch of new skills like 3D modeling and laser cutting and very importantly how to stay on task, which doesn't come easily :P.
Of course this design can be improved, so that's the next step. I'm going to update some of my materials (Like using acrylic, whoo!) In future models of my design, I expect to add an element of automation to it. Now, time to learn programming and circuit boards.
Thank you for reading my Instructable!
Participated in the
Growing Beyond Earth Maker Contest