Closed ecological systems for space travel and extraterrestrial habitation(Reprinted from Developments in Industrial Microbiology, vol 3, pg 5-13, 1962)

Man's requirements for provision of oxygen. food and removal of carbon diox ide and body wastes dictate the necessity for reliable life-support systems aboard a space vehicle or in sedentary habitations on extraterrestrial bod ies. That these basic needs may best be met by expendable systems for rimes up to 30 days has been adequately demonstrated. Extension of navel and hab itation past 30 days imposes the need for nonexpendable or regenerative lif e-support systems. Numerous compelling reasons dictate that management of t hese Life-support logistics can best be accomplished by biological organism s. Thus, the most rational approach appears to he synthesis of an ecologica l system modeled on the balance of terrestrial nature, which is biologicall y dosed but thermodynamically open. The current status of knowledge and res earch in this approach is briefly reviewed. Unexpected problems are discuss ed and the delineation of major unsolved problems undertaken. Problems deal ing with the basic biology of photosynthetic organisms, geometry of culture -vessel configurations, weightlessness, effects of space radiations, generi c stability, and illumination and intermittency effects are considered Clea r differentiation between bio-engineering and design engineering is shown a nd reviewed.