Toward the Development of a “Salad Machine”

During the past three decades, both the Russian and American space programs have demonstrated that human presence in space can be sustained for either short or long durations as long as essential life support expendables are regularly resupplied from Earth. In the last decade, increasing attention has been placed on the development of bioregenerative life support systems which minimize resupply requirements in order to sustain long-duration human exploration of the Moon or Mars and eventually human settlement beyond Earth. Bio-regenerative life support systems, however, remain among the most challenging of all the critical elements required for long duration human space missions. In the near term, the in-space cultivation of salad-type vegetables for crew consumption has been proposed as critical first step towards using bioregenerative technologies to effectively reduce the total reliance by crewmembers on the resupply of food.

Recent advances in the development of space flight plant growth facilities, such as the Plant Generic Bioprocessing Apparatus (PGBA), have established a sound technical basis upon which the implementation of the ‘Salad Machine’ concept may be achieved. Recent plant growth experiments conducted in space indicate that the fundamental biological processes of photosynthesis and growth appear to be essentially the same in space as on Earth. What is currently lacking in making a compelling argument for the development of a ‘Salad Machine’ is information on whether the nutritional content of space-grown salad vegetables is comparable to those grown on Earth. This paper proposes a low cost, near-term approach which would provide these data. A discussion of the preliminary ground-based studies required for determining if the PGBA can successfully function in a salad crop production mode is provided.