Space Flora Systems

This is an entry in the high school level for the Growing Beyond Earth Contest.

After a thorough review of the Instructable contest requirements and parameters, I prototyped and designed an automated moisture control plant pillow and a plant grow box or Space Flora System.

The parameters for this contest are:

· Adhere to the volumetric constraints (a 50cm cube)

· Contain all necessary features for plant growth (light, water, etc.)

· Use 3d-dimensional space in an inventive and effective manner

They also noted that the users should have easy access to the top and the 4 sides of the cube system for easy maintenance and harvesting.

Space Flora System:

The current Veggie Plant Growth System consists of a root mat on the bottom, which, six plant pillows sit upon. To create an environment within the current system, expandable bellows attach to an LED roof or cap. One problem with this system is that it only allows for six plants to be grown at a time and doesn’t optimize the plant’s size during different stages. When a plant is in its germination stage, it requires much less room than a plant in a mature stage. So, to optimize the space in the 50cm cube, I designed a system that uses the plant’s varying size to its advantage. The way the system works is by having expandable bellows, like the existing system, which can move to fit the plant’s needs. In between the bellows (which can be made of clear Mylar) is a printed circuit board, in which blue and red led lights sit and provide light to plants on both sides of the board. The blue and red lights emit light required by the plant. This circuit board (FR4) is lightweight and the LED emitters can be attached directly, to optimize space. Also attached to the circuit board are temperature and humidity sensors, which can be monitored for future experiments. On the top and bottom of the circuit boards are fans, two inlet fans and two exhaust fans. The inlet fans pull in air from outside the system, while exhaust fans push out air from inside the system. These fans are required to remove any CO2 bubbles that form around a plant in microgravity. The fans also help cool the growing chambers caused by the heat from the LEDs. The circuit board also contains a microcontroller and serial communications interface. The microcontroller will run the necessary growing profile required by the particular pants. The circuit board and all of the attachments are secured on a rope on all four corners and can slide up or down when a plant grows and when it germinates. To provide water to the plant pillows in the system, that are described later in my Instructable. A timed constant low pressure supply tube will be attached to the system and fed to the plant pillows to provide sufficient water to the plant. In total on my prototype, there are twelve plants, six of the top and six on the bottom. Plants require more room when they are mature, than those that have just germinated, so you can stagger the start times of the plants to then use the space more effectively. When the top plants are mature, the printed circuit board attached to the ropes can be moved down so the plants can grow fully. When the top plants are in their germination phase, the printed circuit board can be moved upwards, provide more space for the mature plants on the bottom to grow. The material of the top and bottom of the Space Flora System is aluminum because of its lightweight and sturdiness. See models above for info.

Automated Moisture Control Plant Pillow:

One thing that I believe that can be optimized on the current ISS plant environment, is the plant pillow itself. Currently, they use “pillows” or, Teflon-coated Kevlar, box-like shapes with a wick inserted to guide a glued seed out of the pillow. Water is then fed straight to the soil in a quick disconnect feed line. The problem with feeding water straight to the soil is that overwatering can cause root-rot and a loss of a plant, conversely, under watering the plant, causes it to wilt. My solution to this problem is to create a plant pillow which automates the moisture control, to prevent all of the problems listed above. The way this improved plant pillow works is by having three layers inside the pillow, each with an intended purpose. The bottom layer, has a direct water feed line and transfers water to the 2nd layer. In the 2nd layer, there is hydro-gel and cotton from a diaper, which soaks up water and stores excess water, simultaneously feeding it to the soil in the top layer. The 3rd layer, in the plant pillow, has soil and fertilizer, and is the layer that the plant grows. After the water is soaked up by the hydro-gel, it is slowly drawn up to the 3rd layer, when it is needed by the plant, therefore not flooding the soil. By having two layers that transfer water, it forms a valve, that opens when in the 2nd layer contracts (there is less water) and closes when the 2nd layer expands (when it has more water,) automating the irrigating (and moisture control) process. The 3rd layer has a soil and fertilizer mix, but the fertilizer can be also be fed directly from the water reservoir, in a liquid fertilizer state, much like what is used on the space station currently. This plant pillow is only a prototype, so I decided to use only gravitational force to run the water reservoir, however in space this will need to be run off a constant pressure pump, as shown in my Space Flora System. This pump can run on a timed basis for a few min once or twice a week. The required pressure is very low at around 10 cm water column (~0.14 psi).

The key benefit of this automated moisture control plant pillow is that the plants water effectively determines whether the pillow will allow more water into the pillow during the next irrigation. If the plant has consumed the moisture in the soil and the hydrogel, the pillow will open the inlet valve and allow more water to enter the pillow. If the plant has not consumed the water, no more water will enter. The ratio of soil and hydrogel determines how much water will be stored between irrigation cycles and will accommodate the moisture need accordingly.

*Not all of these materials are space approved, as they are only used in a prototype*

· Anti-Static Electronics Bags

· Kapton Tape

· Packing Tape

· Soil

· Fertilizer

· Hydro-gel and cotton (from diapers)

· Plastic Tubing

· Water bottle or water reservoir

· Miscellaneous Wood/screws

Tools to Make an Automated Irrigation Plant Pillow:

· Exacto Knife

· Sharpie

· Ruler

· Scissors

· Drill

· Drill Bits

· Hand saw

· Plastic or small cutting board

1. Take an anti-static electronics bag and cut the resealing section of the top of the bag. Then insert a piece of thick plastic or a small cutting board in between the two layers of the bag. Slowly cut nine x-shaped slits, on only one layer of the bag, ensuring you don’t cut through the bottom. Space out the slits into three rows of three slits, or nine in total, in the center of the bag. The slits are about 1 cm by 1 cm.

2. Take another anti-static electronics bag, cut the resealing section and insert your plastic or board as done with previous bag. Now, carefully cut four squares, that sit in the center of the bag, in a square pattern, not cutting through the other layer. These squares should be approximately 1 cm by 1 cm.

*Refer to the pictures above.

1. Place the two bags so the sides that are cut face each other. The bag with the nine slits is your bottom bag, while the bag with the four squares cut out, is your top bag. Make sure to orientate the bags so the sides that you cut the resealing section face the same way.

2. Take the Kapton tape and tape the two bags together, making sure it is water tight. Then tape two more sides, leaving one side of the bag open.

*Refer to the pictures above

The bags should ideally be sealed using heat to bond the bags together, but as this is only a prototype, tape works just fine.

1. Leave the 1st layer empty, this will be the valve layer and will conduct the water to the hydrogel in the 2nd layer when it requires replenishing.

2. Fill the 2nd layer with the hydro-gel and cotton from a diaper so it covers bottom of the bag.

3. Fill the final, 3rd layer with soil and fertilizer. The soil I used, is a generic potting mix, which, already had fertilizer in it.

4. Tape the open end together with the packing tape, or you could alternatively use a wide strip of Kapton tape, removing all wrinkles in the tape, ensuring a water tight seal.

*Refer to the pictures above

1. Cut your plastic tube to a taper, so it can sit flat in the bag.

2. Make a small incision in the bottom layer of the pillow (the 1st layer) and insert the tube so it runs parallel to the tape seam. Then hot glue the tube in place on the outside of the bag. By doing so, you can utilize surface tension to draw to water evenly throughout the bag and automate the irrigation process, that is explained earlier. In the actual version, the tube inlet should be a flat heat sealed inlet on the outer bag layer.

3. On the top layer (the layer with the soil,) make a 2 cm by 2 cm slit in an x-shape. This is where the plant grows out.

*Refer to the pictures above

1. Take your plastic bottle and cut the bottom of it off, or alternatively drill small holes into it, this will let the water flow into the plant pillow. Drill a small hole on one side of the bottle approximately 3cm from where you cut the bottom off.

2. Drill a hole into the cap of the water bottle that is a tight fit when you squeeze the tube in and hot glue to seal it.

3. Cut the tube so about 3cm of it sticks into the bottle when it is resting. This completes the water reservoir.

4. Use two pieces of scrap wood to create a holder for your water reservoir. One piece of wood should stick up about 30cm high, with holes drilled every 5cm. Attach this piece of wood to a flat piece of wood or plastic, so they are perpendicular to each other.

5. Use the screw or bolt to attach the bottle to the wood, and move it up or down to adjust the water pressure.

*Refer to the pictures above

The plant I used is for show and was not grown in the plant pillow, as it was transplanted.

1. Insert a seed or transplant into the plant pillow. I recommend, to add at least two seeds, in case there is germination failure, as mentioned in a webinar with NASA. Currently, “Outredgeous” red leaf lettuce, is a popular plant choice by astronauts, but other plants are compatible with space.