Design, Build and Testing of Hardware to Safely Harvest Microgreens in Microgravity

Abstract In long-duration space missions, crops will supplement the astronaut diet. One proposed crop type is microgreens, the young seedlings of edible plants that are known for their high nutritional levels, intense flavors, colorful appearance, and variety of textures. While these characteristics make microgreens promising for space crop production, their small size presents a unique challenge within the microgravity environment. To address this challenge, a microgreen planting box was developed to improve microgreen harvest techniques both in 1 g and in microgravity without concern for contamination by roots. Using this microgreen planting box, three parabolic flights were conducted where two different bagging methods (attached and manual) and three different microgreen cutting methods (Guillotine, Pepper Grinder, Scissors) were tested. In flight, the microgreens were contained within a glovebox and footage of all microgreen harvests was recorded. Statistical and trade analyses revealed that the combination of Cutting & Bagging method that performed the best was the Pepper Grinder with attached bagging. This was based on the following criteria: (1) average execution time, (2) microgreen debris, (3) biomass yield, (4) root debris, (5) microgreens left on the hardware, (6) number of seedlings growing under the lids, (7) hardware failure, and (8) perceived ease of use. This process allowed us to identify weaknesses and strengths of all hardware types and helped us identify major points of improvement within the hardware design to harvest microgreens in microgravity. Future directions include microgreen harvests in analog environments and further development of microgreen Cutting & Bagging method.