Pick-and-eat space crop production flight testing on the International Space Station

Fresh, nutritious, palatable produce for crew consumption on long-duration spaceflight missions may provide health-promoting, bioavailable nutrients and enhance the dietary experience. VEG-04A and VEG-04B explored growing leafy greens on the International Space Station using the Veggie Vegetable Production System. Two flight tests with ground controls were conducted in 2019 growing mizuna mustard, where Veggie chambers were set to different red-to-blue-to-green light formulations. Light quality affects plant growth, nutrition, microbiology, and organoleptic characteristics on Earth, and we examined how these vary in microgravity and under different harvest scenarios. Astronauts harvested and weighed mizuna and completed organoleptic evaluations. Flight samples were returned to Earth for nutritional quality and microbial food safety analyses. Yield and chemistry differed between ground and flight samples and light treatments, and bacterial and fungal counts were lower in ground than in flight samples. This research helps increase our understanding of the requirements for growing high-quality crops in spaceflight. The Veggie system can provide astronauts with nutritious, safe-to-eat produce that they enjoy eating, which can help crews stay healthy during long-duration space missions.The duration and method of growing and harvesting crops can influence the yield, organoleptic acceptability, microbial load and food safety, nutritional content, and resources required. A decision on optimum methods will likely involve trade-offs and needs to be weighed against mission objectives.The light spectrum used to grow plants impacts the growth and nutritional content of leafy green crops.Continued research in this area is recommended to test additional crops and to increase research sample sizes.