Optimizing the Structural Subsystem of the AG-Pod Crop Production Unit

The Autonomous Garden Pod (AG-Pod) is a modular crop production system that can lower the equivalent system mass (ESM) for bioregenerative life support systems. AG-Pod combines existing technologies, many of which are at the technology readiness level (“TRL”) 8 or 9, into a flight-ready system adaptable to many needs from Space Station microgravity plant research to interplanetary transit and planetary surface food production systems. The plant-rated module resides external to the spacecraft pressurized volume and can use natural direct solar illumination. This reduces the ESM of crop production systems by eliminating the use of spacecraft internal pressurized volume and by reducing power and heat rejection resources that would be needed for full artificial lighting. However, lowering of the crop production ESM is also achieved from the use of lightweight structures including composite and inflatable technology. AG-Pod's baseline external structure incorporates an inflatable cylinder section capped on either end by rigid ellipsoidal end-caps, one transparent for harvesting direct sunlight. In this paper we outline the configuration options for these main structural components. In each case, applicable materials are identified along with operational and environmental factors that influence their selection. Finally, engineering estimating relationships are developed to enable system sizing trade studies for application to various mission scenarios.