Plant culture system as a water recycling device in space

Plant growth in space has recently been of greater concern as the possibility of realizing manned space activity over a long duration increases. The feasibility of achieving long-duration manned space missions for moon and other planets will be highly dependent on plants in space farming within Controlled Ecological Life Support Systems. Plants will play important roles in food production, CO2/O2 conversion and water purification. In this study, I focused on capabilities of a plant culture system for water purification and recycling, and also food production and CO2/O2 conversion. As a result of a ground-based experiment with sweetpotato, it was shown that 54 m2 culture area can produce food and oxygen necessary for securing one person and 180 L of clean water per day through evapotranspiration. The effect of low gravity on the transpiration was also observed in an airplane parabolic flight experiment and limitation of transpiration due to restricted free air convection under low gravity conditions was suggested.