ABSTRACT

As space missions become longer and longer, a point will be reached at which a system that will produce food at least partly from metabolic wastes will be necessary. In general, the mass of stored food increases as a linear function of crew size and mission length. The physiological requirement is, of course, not for food but for nutrients. All potential on-board food production systems have in common the requirement to meet the nutritional needs of human beings living and working in space for extended periods. Volume, good assimilability, and ease of preparing food from them; the possibility of automatic regulation and control; and the relative independence of physicochemical processes from such significant spaceflight factors as weightlessness and ionizing radiation. In closed systems, there exists the added danger of toxicity at high levels of nutrient elements. There is often a narrow tolerance between the minimum requirement level and the toxic level.