Higher plants are an integral part of strategies for sustained human presence in space. Space-based greenhouses have the potential to provide closed-loop recycling of oxygen, water and food. Plant monitoring systems with the capacity to remotely observe the condition of crops in real-time within these systems would permit operators to take immediate action to ensure optimum system yield and reliability. One such plant health monitoring technique involves the use of reporter genes driving fluorescent proteins as biological sensors of plant stress. In 2006 an initial prototype green fluorescent protein imager system was deployed at the Arthur Clarke Mars Greenhouse located in the Canadian High Arctic. This prototype demonstrated the advantageous of this biosensor technology and underscored the challenges in collecting and managing telemetric data from exigent environments. We present here the design and deployment of a second prototype imaging system deployed within and connected to the infrastructure of the Arthur Clarke Mars Greenhouse. This is the first imager to run autonomously for one year in the un-crewed greenhouse with command and control conducted through the greenhouse satellite control system. Images were saved locally in high resolution and sent telemetrically in low resolution. Imager hardware is described, including the custom designed LED growth light and fluorescent excitation light boards, filters, data acquisition and control system, and basic sensing and environmental control. Several critical lessons learned related to the hardware of small plant growth payloads are also elaborated.

Ensuring high plant yields is critical for the application of higher plants to spacebased biological life support systems. An imager capable of monitoring several fluorescent biological markers in real-time would provide a robust health monitoring system and allow growers to minimize environmental stressors. This article reports the results of the design and development of a multispectral plant health imager prototype, employed in a lowpressure plant growth chamber as a test of its functionality in spaceflight systems. Images were collected every four hours with a monochromatic camera and a commercial liquid crystal tunable filter. This arrangement permitted the monitoring of emission from introduced green fluorescent proteins as well as chlorophyll fluorescence. Data were saved locally and accessed in real-time from the exterior of the chamber.