Engineering Design Analysis of a Microgravity Chamber with Expandable Boundaries for Root Crops

A closed nutrient delivery chamber with expandable boundaries has been developed to support the growth of root crops, with potential applications in microgravity. The chamber is completely enclosed, separating the root zone from the foliage zone with a padded sealant through which the plant stem passes. The expandable boundary chamber (EBC) allows for expansion of the root zone volume, through longitudal pleats, as the plant grows. Two units have been evaluated with a trial crop of sweetpotato (Tuskegee Univ. breeding clone TU-82-155) for 120 days in a greenhouse environment. Storage root yield per plant in the EBC averaged 1.33 kg in comparison to 0.3 kg for the conventional Nutirent Film Technique (NFT) grown plants. This excellent yield warrants further design refinement and serious consideration of the system for earth use and microgravity applications.