Advanced System for Growing Plants in Microgravity

John F. Kennedy Space Center, Florida

The figure depicts the Biomass Production System (BPS), which is an advanced system that provides controlled conditions for growing, manipulating, sampling, and harvesting plants in microgravity for both commercial purposes and scientific research. The design of the BPS incorporates lessons learned from the operation of prior plantgrowth systems aboard spacecraft in flight. Examples of uses for the BPS include (1) metabolic experiments that can include photosynthesis, respiration, and transpiration; (2) biotechnological plant investigations; and (3) side-by-side comparison of multiple plant-growth techniques and conditions. Plant biomass is easily accessible during all phases of operation.

The Biomass Production System is a modular system that provides controlled conditions for growing plants in microgravity.

The subsystems of the BPS feature modular designs. The BPS currently includes four plant-growth chambers with independent monitoring and control of temperature, humidity, lighting, the concentration of CO₂ for each chamber, and nutrient delivery. The chambers are sealed for gas-exchange measurements, and there are multiple gas/liquid-sampling ports. By modifying the design, the chamber configuration can be changed from four independent chambers to two tall, two wide, or one large chamber.

The overall operation of the BPS is coordinated by an advanced electronic control and monitoring subsystem with a capability for automated diagnosis. Features of this subsystem include one video camera (with expansion capabilities to two cameras) in each chamber for observation in real time, a fully equipped computer with a serial port and an Ethernet interface for direct transfer of data, enhanced capabilities for acquisition and storage of data (including image data), fuzzy logic for control of temperature and humidity, front-panel controls with full command authority, a high-resolution color front-panel display, indicators of operational status, an interface key pad, a standard floppy-disk drive, a standard keyboard interface, programmability of data-handling functions, and menu-driven software with optional displays defined by the user.

The BPS includes modular lighting and active metered nutrient- delivery subsystems that can be controlled separately or together. The temperature-control subsystem includes a highperformance thermoelectric controller. The lighting-control subsystem includes an efficient sold-state ballast light-controller/ driver circuit. Other subsystems include a replenishable CO₂ supply, a regenerative H₂O-recovery loop, and a replenishable H₂O supply.

This work during the SBIR Phase I and Phase II efforts included contributions from Ronald J. Anderson, Thomas M. Crabb, John G. Frank, Steven M. Guetschow, Jeffrey T. Iverson, Olaf Meding, Robert C. Morrow, E. Don Peissig, Ross W. Remiker, Robert C. Richter, David Smith, Jon D. Van Roo, Anton G. Vermaak, and John C. Vignali of Orbital Technologies Corp. for Kennedy Space Center. For more information, contact the Kennedy Commercial Technology Office at (321) 867-6224.

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