Introduction: GAIA - Growing Beyond Earth Maker Contest
High School Category Entry
As members of the STEEEM Club (Science, Technology, Engineering, Environment, Entrepreneurship, Math) at Palmer Trinity School in Miami, Florida, we are more than delighted to take on this project because it fits so well with multiple goals that our club prioritizes. Our group is comprised of 9th and 10th graders. After working tirelessly many days after school, we believe we have come up with the optimal design for a plant box on the I.S.S. We believe we accomplished this difficult feat using aeroponics, which research conducted by NASA (Griffin 2006) shows to be the most efficient growing technique in space. Our idea is to use a four-sided growth system to cultivate plants on an offset weekly cycle to produce 8 heads of lettuce per week, equaling 32 heads of lettuce per month. Comparatively, the original technique used in Veggie only allowed for 6 plants per month. We hope the astronauts enjoy their delicious space salads. Aeroponics has revolutionized our idea of efficiency. With that in mind, we look forward to continuing to work on this project because it encourages our passion for space, engineering, and the environment.
After some research, we discovered that NASA names many things after Greek mythology. That is why we decided to name our box GAIA after the Greek goddess of the Earth. GAIA stands for Growth Apparatus in Astro-environment. If GAIA is brought to space, it will bridge the gap between Earth and space. GAIA represents mother Earth, and as the human race expands into space, we need to remember where we came from and bring a little piece of our home with us. Maybe 1000's of years in the future when humans are living on a new planet, people would see a highly modified form of GAIA and remember their ancestors' home.
Step 1: Gather Materials
Polycarbonates (0.5cm thickness)
- 2 x 50cm by 50 cm Polycarbonate sheets
- 2 x 50cm by 49 cm Polycarbonate sheets
- 2 x 49cm by 49 cm Polycarbonate sheets
- 2 x 48cm by 40 cm Polycarbonate sheets
- 2 x 48cm by 39 cm Polycarbonate sheets
- 8 x 48cm by 4cm Polycarbonate sheets
- 4 x 28cm by 1.5 cm Tubes
- 4 x 3.5cm by 1.5 cm Tubes
- Methylene Chloride and Ethylene Dichloride (we won’t know how much we’ll need until we try this method)
- 3D printed fan connector
- Miniature 5V Cooling Fan with Molex PicoBlade Connector from Adafruit
- LED light strips that produce 300-400 𝜇mol/M2/s within PAR (400-700nm)
- Hollow 3d printed plastic pipe with a 2 cm diameter
Light and Fan System
- 2 small motors
- 6 rods
- 12 specialized gears
- 4 chain gears
- small 100psi diaphragm water pressure pump with a built-in pressure switch
- small waterproof electric solenoid
- 1 cm diameter plastic tubing
- fine-mesh filter
- Orifice capable of producing water droplet of 30 microns
- Air Stone
- Arduino Mega
- All sensors listed in the electronics section
- Piano/continuous hinge 40 cm
- Neodymium Magnets
CAD file linked below or can be found on Tinkercad under the name "STEEEM Club"
Step 2: Gather Tools
- Laser cutter
- 3D Printer (Make sure that the print bed is large enough for the parts mentioned later on)
- Circular saw
- Square layout tool
Step 3: Outer Frame
For bonding the sheets together refer to these instructions:
- Clean the areas that need to be joined with lukewarm, soapy water and a gentle sponge (wiping in the direction of the grain).
- Apply a small line of 60-40% mixture of Methyl Chloride and Ethylene Dichloride along the edges of one sheet.
- Wait for the mixture to soak into the sheet and become slightly sticky.
- Apply a light pressure on the sheets to strengthen the bond.
- To make a right angle use right-angle things.
- Let it dry for at least 48 hours in a well-ventilated area.
Making the Frame
- Laser-cut larger polycarbonate sheets into the correct sizes listed in the materials above.
- The 50cm by 50cm sheets are the top and bottom.
- The 49cm by 50cm sheets are the left and right sides.
- Bond the left and right side to the bottom as shown in picture 1.
- Note: Numbers are in the top left corner.
- Then bond one of the 49cmx49cm sheets to the back as shown in picture 2.
- Note: Bonding the top and front will happen last.
The outer framework will be made from polycarbonate sheets. The sides will be fused using a 60-40% mixture of Methylene Chloride and Ethylene DiChloride. This mixture will increase the curing time compared to using Methylene Chloride alone, which will allow more time to get the parts in their correct positions. Fusing the sheets like this will provide exceptional strength and allow the structure to be waterproof. All will be fused except the front flap (which will be connected with a continuous hinge and magnets). Another benefit of using polycarbonate is that it is transparent, so astronauts can observe their plants without opening the box.
For more details about fusing:
Step 4: Water Reservoir
- Cut out 8 x 48cm by 4cm polycarbonate slices.
- Laser-cut a hole that is 1.5cm in diameter in each of the 8 x 48cm by 4cm Polycarbonate sheets, 5cm away from the side closest to the front, as shown in picture 3.
- Laser-cut a hole that is 1.5 cm in diameter in each of the 8 x 48cm by 4cm Polycarbonate sheets, 15cm away from the side closest to the front, as shown in picture 4.
- Bond them to the box as shown in picture 5.
- The measurements are the same on all sides.
- Using the PVC pipe connect all the water reservoirs and plant root zones as shown in picture 6.
- The orange pipes represent the water reservoir pipes.
- The light blue pipes represent the mist delivery pipes.
- Note: Connections are not included in photo 6 and dimensions are the same for all sides.
Step 5: Assembling the Aeroponic System
- Attach the pump in the spot shown in picture 7
- The pump that we have found is probably not NASA grade so we should use a smaller, more capable pump.
- SEAFLO 12V DC 1.3 GPM 100 PSI 22-Series Diaphragm Water Pressure Pump
- Other motors can be used, but they must be 100 PSI and extremely similar, or preferably smaller than the one listed.
- Using the larger pump above will require minor changes to the section of polycarbonate it is under.
- The change will require added polycarbonate pieces that will be bonded around the motor.
- Note: For the changes 3 and 4 above, the changes to the polycarbonate will be on the bottom left of the inner frame mentioned next. We assumed that no change will be needed because there could be smaller pumps available that we have not found yet.
An experiment conducted by NASA astronauts aboard the International Space Station in the 1990s concluded that aeroponics with a droplet size of 5 - 50 microns are the most efficient way to grow plants in space. Due to the size and reusability of the system, it will reduce cargo costs for NASA. According to NASA’s research on aeroponics, it saves 98% of water and uses a third of the nutrients compared to traditional growing techniques. The water/nutrients basin will be filled up by astronauts with water and liquid nutrient mixture. Using normal liquid water, a full-grown plant needs 100ml of water a day. However, our system uses water vapor which will reduce water usage by a significant amount. We believe that the astronauts will only need to fill the water basin once per month further decreasing astronaut intervention.
Our high-pressure aeroponics system will use an interval/duration spray technique to produce healthier roots. Using this method, the roots will be more resilient. In the case of system failure, the system will go into "save the plant" mode, both lowering the light intensity and temperature. The orifice will be capable of producing drop sizes of 30 microns. This means that the drops will act the same way on earth as in microgravity, therefore reducing or even eliminating the use of meshes to control the capillary action of the water in microgravity. The air stone will provide the root zone with sufficient oxygen. (Clawson 2000)
Step 6: Assembling the Inner Frame
- For the top and bottom of the inner frame, take the 2 x 40cm x 48cm sheets and laser cut out a 24.5cm x 46.5cm rectangle in each one. They should look like picture 8.
- For the left and right sides of the inner frame, take the 2 x 39cm x 48 cm sheets and cut out a 23.5cm x 46.5cm rectangle in each.
- Bond these together. They should now look like the picture 9.
- Bond the sheets to the back of the box. There should be a 4cm gap between the newly added box and the original. It should look like picture 10.
- Cut out a 40cm x 40cm square from the 49cmx49cm sheet. It should look like picture 11.
- Save the 40cm x 40cm square for later.
- Cut out a hole with the diameter of the one-way water valve.
- Note: We do not know the size of the nozzle Portable Water Dispenser the ISS uses.
- Bond that square to the main box as shown in picture 12.
- Note: In picture 12 there is a hole for the water valve.
- Make sure that everything is sealed.
In order to avoid overcrowding, our design prevents plants from converging at a corner.
Step 7: The Light and Fan System
Our 2 in 1 light and fan system is specifically designed to save as much space as possible. The approximation of how the system will look is shown in picture 13.
- Using a CAD model, print the light-to-fan connector out of plastic in the picture above.
- Note: The fan we used in our prototype was a normal desk fan, but we recommend using a smaller high-efficiency fan such as a computer cooling fan like the Miniature 5V Cooling Fan with Molex PicoBlade Connector from Adafruit. With a smaller fan, the CAD model will need to be adjusted accordingly.
Movable light system
- Note: The following is best represented by the pictures of the 3D printer above since the mechanism will be almost identical just more compact. Measurements cannot be confirmed yet. Some materials are not listed in the materials section because we do not know enough about them.
- Glue the 3D printed cover and connector around the fan to the 3D printed plate that will attach to the following mechanism.
- Four rods will be placed on four sides and the gears will be connected at each end of the rod.
- The rubber treads will then be added on to the gears so they can rotate.
- Two rods will make a plus in the middle through the light fan connector.
- The motor will move the treads which will orient the lights at any point in an x-y axis in our box.
- To eliminate the problem of astronauts potentially breaking the system they should cut the pipe about 5cm away from where it meets the 3D printed fan to light connector and glue them together using a minimal amount of glue. Now, if the pipe breaks it can easily be fixed rather than breaking the entire system.
- Connect the LED light strips around the pipe equally.
- The pipe will have holes that allow for adequate airflow around the box so make sure that the lights are not on the holes.
- Slide the pipe into the 3D printed connector.
The lights in our prototype model picture are mounted on a white tube made of cardboard coming out from the back sheet of the box. In real life, if our design were to be approved, this system would be made mostly from 3D printed parts. It will have UV lights mounted in a circular form around the tube. This will provide light for the plants that will be placed around the box. The pole that the fan and lights are attached to will be moved by an x-y axis motor similar to the one used in a 3D printer so that the plants don’t accidentally grow into the pole. The system will be controlled by our Arduino program and will adjust itself around the box for the optimum distance away from the plants. The Arduino will also reduce the power in different sections of the light system to help prevent tip burn. To save space, this system will have to be previously calibrated instead of using a sonar sensor to help find distances. To make this movable light and fan system, we chose to model our system after a 3D printer. Many components can be bought from Adafruit.
Step 8: Electronics
- Put the Arduino Mega in its case.
- Connect it to the upper left part using Loctite. It should now look like picture 14.
- Connect all of the electronics to the Arduino using the appropriate wires.
- Note: For the Aeroponic system, this might involve drilling into the polycarbonate and sliding the wires out to the Arduino.
- Drill a hole through the back polycarbonate sheet, but above the water reservoir to fit a wire through for power.
The focus of this phase of the project is to use the 3D growing space efficiently to grow plants in space, so we were not required to program an Arduino yet. However, using an Arduino, all the electronics in the system will be managed and controlled. The Arduino will control the pump to circulate mist throughout the system, release the mist when it is needed, and turn the fans and lights on and off when needed. All the electronics in the box will be connected by the appropriate wires. The sensors/components that we will need to attach to the Arduino are listed below. Many sensors can be bought from Adafruit.
- Temperature Sensor
- Humidity sensors
- Electrical-Solenoid connected to an adjustable relay timer
- A volt converter (we don’t know how many volts the system will run on yet)
- LED Strips
- Bluetooth module for connection to onboard screens
- The motors for the light system
- Small fan
- The water pump
- Air Stone
Step 9: Grow Medium
- Place the air stone in the bottom grow area.
- An air pump/stone will be connected to the outside environment (to intake air).
- Connect the intake of the airstone to the box's open spot in the back and wire to the Arduino.
- Cut the rock wool into a 24.5cm x 46.5cm piece.
- Cut the rock wool horizontally across in half so that it is a thinner layer and the roots reach the water more quickly.
- Secure the rock wool in place using glue on the edges.
- Note: The rockwool's top should be flush with the top of the water reservoir next to it. This will leave enough room underneath for the plants' roots.
Rock wool is our growth medium of choice to implement in the aeroponics system. But, there are other options for the growth medium. We can also design our own system to hold the seeds in place. After speaking to local hydroponic experts, lots of research, and some testing we believe that our "grow zone" will work in microgravity.
Step 10: Adding the Plants
Note: We recommend doing this step last, after you have finished the box and checked all of the components. We decided to include it here since the growth medium is as fresh in your mind as the lettuce the astronauts will be eating.
- Each seed will then be placed root side down, 10cm apart, as shown in our actual test picture above.
- The plants will then be 2 by 4 resulting in 8 plants per side.
- There should be 10 cm of space between the plant and the inner wall.
- According to NASA, harvesting will take place when plants reach full maturity after 28 days. Therefore, the plants will be put on a weekly cycle, so astronauts can munch on 8 full lettuce heads a week.
- We recommend not harvesting the entire lettuce all at once, but rather letting some leaves remain, so the astronauts don't need to replant.
On earth, red romaine lettuce grows well with this spacing technique so that is why we chose to implement it.
Step 11: The Door
- Attach the magnets to the spot in the box with Loctite as shown in picture 15.
- The width is 0.5 cm.
- Attach the other magnets to the door with Loctite as shown in picture 16.
- The door is transparent in the photo and the magnets have to line up exactly with the other magnets on the box.
- Put the door aside after this is done.
Step 12: The Roof
- Bond the final piece to the top as shown in picture 19.
Step 13: Future Automation Plans
If we make it to phase 2 (fingers crossed!), we plan to incorporate a completely automated plant harvesting system that will only require astronauts to fill up the water reservoir. That won't be necessary if there's a connection to the onboard water system. But, there will still be an option for astronauts to interact with the plants. Because we’re using rockwool, however, it might need to be replaced every couple of months in an aeroponic system.
Step 14: Conclusion
We are so grateful to have the opportunity to participate in this contest and we hope that we can move on to see our vision grow. We have learned so much about plants, space, engineering, and communication. As humans expand their presence in space, we are excited to be a part of the effort to make space travel sustainable.
Step 15: Bibliography
Aeroponics DIY. Web. January 20, 2020 https://aeroponicsdiy.com/make-your-own-high-pres...
Clawson, J. M; Hoehn, A; Stodieck L.S.; and Todd, P. Aeroponics DIY. 2000. Web. January 17, 2020. https://aeroponicsdiy.com/nasa-review-of-aeroponi....
Frog, Tree. Maximum Yield 18 September 2017. Web. November 20, 2019. https://www.maximumyield.com/fogponics-a-new-spin....
Griffin, Michael, and Mckenzie, Merle. NASA. 2006. Web. January 15, 2020 https://www.nasa.gov/pdf/164449main_spinoff_06.pd....
Third Prize in the
Growing Beyond Earth Maker Contest