The future of manned space exploration will be determined through a process which balances the innate need of humanity to explore its surroundings and the costs associated with accomplishing these goals. For NASA this balance is derived from economics and budgetary constraints that hold it accountable for the expenditure of public funds. These budgetary realities demand a reduction in cost and expenditures of exploration and research activities. For missions venturing out to the edge of habitability, the development of cost effective life support approaches will have a significant influence on mission viability.Over the past several years a variety of mission scenarios for Lunar and Mars missions have been developed. The most promising of these attempt to provide basic mission requirements at a minimum cost. As a result these missions are extremely power limited. For Closed Environment Life Support System (CELSS) applications these realities impose both limitations and direction for future research. This paper presents a summary of these mission scenarios and an evaluation of the potential of CELSS based life support systems to impact the costs of these missions.