The known Universe is 92 billion lightyears in size. Yet, ironically, volume available for plant experiments in space is often limited to mere centimeters. This presents a challenge for growing plants in space for food, research and other purposes.
Consequently, inspired by the cube sat movement, SustainSpace has been developing a suite of 1U–2U cube form plant growth chambers involving minimal volume and mass. Ultimately intended for space research, SustainSpace is also developing an inexpensive STEM version for educational use on Earth, using “off-the-shelf” components.
A goal of this project is to introduce students to concepts related to growing pants in space, such as inputs and outputs, constrained volume, sensing and controlling. Another goal is to eventually produce a chamber that is better optimized to actually grow plants.
Sustainspace has developed version 1.0 of the STEM version chamber. This version is a baseline STEM chamber intended to demonstrate key concepts and be relatively simple to construct. It requires no soldering, but patience is helpful.
It contains colored LEDs for illuminating plants and signaling growth direction and several. It is built around a 1U (10 cm^3) translucent plastic frame. In one configuration, plants are contained in open air in a pullout square petri dish tray, but could be placed in other enclosures (sealed or open air).
An Arduino controls multicolor LEDs and monitors temperature and humidity sensors. Data transmission is through a cable attached to a computer. However, the chamber LEDs can be operated by connecting a simple 9 Volt battery to the Arduino. LEDs are pulsed to provide red light to give the plants energy (via photosynthesis) and blue light to communicate desired growth direction.
This version is not intended to provide the necessities of growing plants, aside from a small proportion of required light. The 1U frame is translucent with large openings to allow air and light to enter the cube. The plants will also need to be watered. This chamber is only 10 cm tall, so plants may periodically need to be trimmed to fit inside.
Our baseline test plant is chives. They can germinate in a media-filled petri dish and grow in the chamber. Periodic trimming provides a nice food garnish. If protection against evaporation is provided, the chives can be neglected for weeks, allowing them to survive school breaks. A square petri dish can slide in and out of the chamber like a drawer. For simplicity, soil can be used as the root media, but gel and netting can be used if the chamber is rotated to simulate microgravity.
For further information, please see the Project Page.