Space Crop Considerations for Human Exploration

Why Plants? As humanity prepares to extend its presence beyond Earth, an exploration food system that ensures the physical and psychological health and performance of the crews will be required. In 1964, the NASA Associate Administrator of the Office of Advanced Research and Technology, Raymond Bisplinghoff, stated, “We may develop boosters and guidance and control systems and reentry systems of exceptional efficiency, but unless we can at the same time sustain life in space we cannot have a manned space flight program”. This is arguably one of NASA’s first statements that focuses on food systems for astronauts. Experience with the current food system on the International Space Station (ISS) shows that some vitamins degrade and quality declines in the existing prepackaged food over multiple years of storage at 21°C. Additionally, the ISS prepackaged food system contains approximately 46% water. Based on current assumptions, logistics for a Mars mission requires a 5-year or longer shelf life and a significant mass reduction. The Human Research Program (HRP) has been evaluating methods to increase shelf life, which includes a resource impact in the need for cold storage, while the Mars Campaign Office (MCO) is seeking to reduce the water content of prepackaged food to 30%, which may result in a resource savings, but would require evaluation of impacts to variety, choice, and nutritional intake prior to implementation. In light of these issues, HRP and MCO are also investigating supplemental crop systems, which includes evaluation of crop growth within the challenges of spaceflight, resource requirements including mass, volume, power, crew time, cleaning and safety testing, and impacts to other resources, such as water, and how this trades with contributions to human health and performance. In support of these investigations, MCO is investing in the development of a supplemental crop production capability called Ohalo III. On board the ISS, Ohalo III may be used as a testbed for the development of crop growth systems and technologies, as well as implementation of a food safety program for pick-and-eat crops. Ohalo III may also be used to test candidate crops that meet spaceflight resource and safety requirements and provide continuous supplementation of astronaut nutrition, while validating the psychosocial benefits of having plants accompany astronauts on long duration exploration missions.