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This paper reviews the preliminary definition of integrated life support system configurations based on a single criterion decision-making task (SCDMT). Comparative analysis results are shown for currently used effectiveness models based on SCDMT. Possible areas of application for those models are determined. It is also proven that well-known effectiveness model, which uses an equivalent mass approach to determine system expenditures, can be used only in cases where useful effect from system operation is the same. The article proposes the use of a global thermodynamic effectiveness criterion based on the exergy method to account for ECLSS functional expenditures, i.e. functional costs. Exergy is a concept that fuses energy and material quality information in a measure that is both descriptive and physically significant. This method accounts for nonequivalence of different forms of energy and allows measuring technological flows in the system using same measuring units.

This paper reviews a Crew Simulation Model (CSM) for Space Vehicle Integrative Life Support System (ILSS) operation study. It is designed to simulate crew metabolic reaction mass and energy flows in accelerated time mode with each crew member specifics consideration. This CSM formally is based on human body general simulation, which includes main functional systems like: the cardiac-vascular, external respiration, thermal regulation and water/mineral balance. Work and rest time schedules are also considered as well as each crew member presence in a particular module. The CSM considers trace contaminants in metabolic products due to nutrition and environment temperature. This simulations' formal review is shown in the paper as well as formal implementation with computed experiment results. Some of the possible applications are also approached.

Among the challenges of designing and constructing Space Station Freedom is the development of the water system. A review of past efforts in reclaiming waste water in enclosed environments reveals that there are many gaps in the biomedical understanding of this process. Some of the key uncertainties of human interaction with a closed water system include determining potential contaminants and establishing safe levels of multiple compounds in the enclosed system of Space Station. Another uncertainty is the microbial constituency of such a system and what impact it could have on crew health and performance. The use of iodine as the passive biocide may have both an indirect and direct impact on the crew. In this paper the initial results of the Water Recovery Test are reviewed from a biomedical perspective, revealing areas where more information is needed to develop the ECLSS water system.

Throughout the history of manned space flight the supply of potable water to the astronauts has presented unique problems. Of particular concern has been the microbiological quality of the potable water. This has required the development of both preflight water system servicing procedures to disinfect the systems and inflight disinfectant addition and monitoring devices to ensure continuing microbiological control. The disinfectants successfully used to date have been aqueous chlorine or iodine. Because of special system limitations the use of iodine has been the most successful for inflight use and promises to be the agent most likely to be used in the future. Future spacecraft potable, hygiene, and experiment water systems will utilize recycled water. This will present special problems for water quality control. NASA is currently conducting research and development to solve these problems.