The use of plants for bioregenerative life support for space missions was first studied by the US Air Force in the 1950s and 1960s. Extensive testing was also conducted from the 1960s through the 1980s by Russian researchers located at the Institute of Biophysics in Krasnoyarsk, Siberia, and the Institute for Biomedical Problems in Moscow. NASA initiated bioregenerative research in the 1960s (e.g., Hydrogenomonas) but this research did not include testing with plants until about 1980, with the start of the Controlled Ecological Life Support System (CELSS) Program. The NASA CELSS research was carried out at universities, private corporations, and NASA field centers, including Kennedy Space Center (KSC). The project at KSC began in 1985 and was called the CELSS Breadboard Project to indicate the capability for “plugging in” and testing various life support technologies; this name has since been dropped but bioregenerative testing at KSC has continued to the present under the NASA’s Advanced Life Support (ALS) Program. A primary objective of the KSC testing was to conduct pre-integration tests with plants (crops) in a large, atmospherically closed test chamber called the Biomass Production Chamber (BPC). Test protocols for the BPC were based on observations and growing procedures developed by university investigators, as well as procedures developed in plant growth chamber studies at KSC. Growth chamber studies to support BPC testing focused on plant responses to different carbon dioxide (CO2) concentrations, different spectral qualities from various electric lamps, and nutrient film hydroponic culture techniques. This Technical Memorandum (TM) gives an overview of activities leading up to the KSC Breadboard Project, a description of the BPC, and summaries of crop test data, including the following: • Environmental and horticultural approaches. • Observations on growth and development. • Crop biomass and oxygen yields. • Proximate composition of biomass. • Whole stand photosynthesis and respiration rates and responses. • Nutrient solution measurements, including water use, nutrient uptake, and acid additions for pH control. • Ethylene and other volatile organic compound production by plants. Because of the extent and diversity of crop testing at KSC during the 1985 to 2002 time frame, the results and discussion are limited primarily to BPC studies with wheat, potatoes, soybeans, lettuce, and tomato. An expanded bibliography of plant-related CELSS/ALS research is included at the end of the document. The intent of this TM is to provide both a general summary of the crop studies at KSC as well as a template for compiling a user’s guide or handbook for growing crops for Advanced Life Support systems in space. Because knowledge on growing plants for life support is continually expanding, the specific set points and outputs from ALS cropping systems will continue to be refined and improved. A crop handbook detailing these outputs and horticultural approaches may one day provide an invaluable reference for sustaining life support “farms” and the success of future space missions.

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