Introduction: Fogponics/Aeroponics in Microgravity
Fogponics/Aeroponics in Microgravity
Growing Lettuce for the International Space Station.
This is a professional entry into the Growing Beyond Earth Maker Contest.
The concepts in this Instructable address the following:
1. Maximizing space use to grow lettuce and other plants on the International Space Station by grouping/spacing plants based on the age/size.
2. Addresses water needs through a novel sealed Fogponics/Aeroponics system that can even water the plants varying amounts based upon their needs.
3. Configured to provide 5 heads of lettuce every week with only one weekly interaction by the astronauts.
~24' of 1"x1" wood
11 white 1/8" hardboard panels 19.5" square
#8 x 1" wood screws
Silver Spray Paint
Aluminized Mylar (Space/Emergency Blanket)
3M 77 Spray Adhesive
5/16" thick closed cell foam
1-1/8"diameter foam disks; 1/2" lengths (Foam Hair Curlers at Dollar Tree)
1" dia PVC Electrical Conduit (25 - 7cm lengths)
1/4" barbed 'T's and 'Elbows' (drip irrigation supplies)
1/4" OD vinyl tubing
Nebulizer - The kind the doctor provides to inhale vaporized medicine (see eBay)
Computer Power Supply
Automotive Air Compressor
Refillable Ennema Bag with tubing (non rigid reservoir for water/nutrient)
LED grow light; 16.5', 5050 4:1 Red/Blue
3D printed locking ring; Qty 25
Computer Fans (to keep air circulating)
Control system to cycle lamps
Step 1: Maximum Space Utilization
The plants are organized in 5 groups of 5. This provides 5 lettuce plants to consume each week; taking 5 weeks to go from seed to head. 25 plants at any given time.
In the diagram the new seeds start at the far right close together. The plants are contained in removable tubes that can be moved from station to station. As the plants mature and need more space they are moved to the next station that provides the needed extra space; both side to side space and also more overhead space to grow.
A streamlining concept would provide a slot as wide as the tube from station to station to allow the plant tubes to be unlocked and then slid to the next station, rather than being pulled out, where they would be locked in place.
An automated system to advance the plants from station to station is in the preliminary concept stage.
Step 2: Plant Carrier Tubes
The plants are contained in moveable open-bottom plant tubes. The tubes, when installed on a 'station' location, twist lock in place and make a seal to a nebulizer at the bottom.
Carrier tubes are provided with a 3D printed locking ring at the top that secures the plant tube onto the carrier tray. The plants are held in place in the tube by a foam ring. Seeds are held in place between two pieces of coffee filter material which extend down into the carrier tube to pull water up to the seeds. As the plants grow they displace the foam.
The tubes are 1" diameter PVC electrical conduit. The pink foam ring is from foam hair curlers found at the dollar store. They foam is cut into disks about 1/2" thick.
Plants are watered by nebulizer generated fog from below. Because the plants are located in removable tubes any seeds that fail to germinate or plants that are poor performers can be easily replaced.
Step 3: Fogponics/Aeroponics Closed System
Fogponics/Aeroponics is a growing system where the roots of the plants are never submerged in liquid and are not provided with a growth medium. The roots hang free in space.. The roots are bathed in spray or mist; or in this case fog (atomized solution).
Each plant is watered by a nebulizer at the bottom of the plant 'station' location. This nebulizer is the same type the medical doctor provides to atomize medications for inhalation. The nebulizer is provided with compressed air and a water/nutrient solution that is fed by capillary acton. The action of the compressed air creates a venturi that pulls the solution into the nebulizer where it is vaporized.
The plant tube is also provided with a drain tube connection next to the nebulizer to allow the compressed air to escape. The drain can also be used to remove excess water vapor by blowing air through the nebulizer without allowing solution to flow. The drain system can return liquid/vapor to a centrifugal separator to pull the liquid out and recycle the nutrient solution.
Since each plant has its own nebulizer the plant can receive custom tailored watering programs either individually or as groups. Multiple plant stations can be grouped to be watered simultaneously or singled out to receive specific amounts of water/nutrient based on water line and valve configuration.
The nebulizer was modified to add the water-in connection on the side and provide a closed-loop system.
Only one nebulizer assembly was fully built as a test bed for the concept.
Step 4: 50 Cm on a Side Cube
The cube is constructed with a 1"x1" wood frame. The frame was spray painted silver. The frame is covered with 5 panels composed of 1/8" white hardboard with aluminized mylar attached to the non-white side. The mylar was attached by spraying the panels with 3M 77 Spray Adhesive and smoothing the mylar onto the adhesive.
Step 5: Plant Trays With 'Stations'
The plant trays were laid out on cardboard templates to adjust the spacing of the plants to increase as the plants progressed from seed to harvest. A drill was used to drill a small hole to mark the center of the holes on the templates. A hole saw was used to drill the large holes for the plant tubes.
Notches were provided on sides of the holes to allow the tabs on the locking ring to engage. The stations were installed into the cube. LED lights were installed.
Water reservoir, air compressor and control valves can be located under the bottom tray between the plant tubes.
Step 6: Operation
Each week the astronauts can harvest 5 heads of lettuce and install 5 new plant tubes with seeds in them at the starting side. Each week as 5 lettuce plants are harvested all the plants are shifted up 5 spots and twist locked into place over a nebulizer. The new seeds are installed in the 5 new openings.
Happy growing - Enjoy!
Runner Up in the
Growing Beyond Earth Maker Contest