3D printed aeroponic tray nutrient delivery system for bioregenerative life support systems

Abstract

Bioregenerative systems incorporating higher plants are recognized as a promising life support system option for future long-duration space missions. Aeroponic nutrient delivery systems have been regarded as a suitable method to grow plants in space due to their low mass penalty compared to soil cultivation and traditional hydroponics. Presently the German Aerospace Center’s EDEN research team has been utilizing standard Euro boxes/trays as aeroponic root zone compartments. The boxes have been modified to incorporate aeroponic tubing with misters and include manually constructed covers to hold the plants. Several limitations with this approach have been identified including seed pinching, presence of stray light, and adaptation to plant spacing over time. A new custom tray is designed firstly utilizing strong plastic holders replacing rubber holders to be plugged into traytop holes. Pressure surrounding the seed is eliminated to prevent pinching. Black coloured body is chosen together with side protrusion on its traytop to block stray light. The new design is also complete with traytop variants to accommodate growing plants and increased canopy cover. The variants include 4-hole, 2-hole and single-hole traytops. The root compartment also includes several added sections to cope with growing plant roots. Feedlines for the misters are placed outside the container to facilitate better cleaning and the container floor is elevated with a 3° angle to direct water to its drain hole. Seal rings and rubber strips are added onto the plastic pucks and their insert location on the traytop to seal off against water leakage. Extra parts, rock-wool holders and crop-stands, are also made for cultivating various other target plants. 3D printing was chosen to build test prototypes. Acrylonitrile Butadiene Styrene was selected as the build material for its good surface finish, robustness, durability and water resistance. Issues with the current aeroponic trays are solved through the custom designed aeroponic trays. Further developments can be done through implementing a technique for better surface finish on angled surfaces and larger printing sizes. These aeroponic trays are planned to be utilized in the EDEN ISS Antarctic greenhouse module project and within future microgravity/planetary surface plant production systems.