Plant Research Unit - Program Overview and Update 2002-01-2279

The Plant Research Unit (PRU) is the Space Station Biological Research Program plant growth facility being developed for the International Space Station. The plant habitat is designed for experiments in near-zero gravity or it can be rotated by the ISS Centrifuge for experiments at any gravity level from microgravity to twice Earth's gravity. Plant experimentation will be possible in multiple Plant Research Units at one time, isolating the effect of gravity on the biological specimens. The PRU will provide and control all aspects of a plant's needs in a nearly closed system. In other words, the shoot and root environments will not be open to the astronaut's environment except for experiment maintenance such as planting, harvesting and plant sampling. This also means that all lighting, temperature and humidity control, nutrient delivery, and air filtering and cleaning must be done in a very small volume, with very little mass and power usage and with minimal crew time. The PRU will be a fourteen-panel unit experiment interfacing with the Habitat Holding Rack and Centrifuge Rotor. The PRU will provide continuous data logging of the environment including video images of the plants. The system will be robust enough for 10 years of life and dozens of trips to and from orbit. The Plant Research Unit will provide a significant new science capability that could accelerate biotechnology and controlled agriculture applications on Earth. This paper will review the status of the program. Discussions will encompass the prototype testing that has taken place, expected capabilities of the flight unit, and research preparations that could be conducted using the Science Evaluation Unit.