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The paper systematizes typical hydrodynamic and heat-and-mass transfer chemical engineering processes realized in water recovery systems. The impact of micro-gravity on the processes is analyzed and general principles of the process organization in gas/liquid fluids are described. As examples, some typical separation processes in a coccurred flow channel with liquid suction through a porous wall, liquid evaporation into a vapour/gas fluid and vapour condensation from the vapour/gas mixture are considered for water recovery systems. A versatile approach based on an extended analogy between friction, heat transfer and mass transfer and on limited relative laws of a boundary layer at the permeable surface is suggested for an analysis and calculation of the friction resistance of a two-phase flow, heat transfer and mass transfer on evaporation and condensation. Recommendations for an analysis of the influence of free convection are made.

A concept of LSS building for planetary stations is suggested on the basis of experience in the development, research and testing of physical/chemical regenerative LSS for long-duration ground-based bio-technical complexes of habitat support and for orbiting space stations. A gradual transition from integrated physical/chemical regenerative LSS to hybrid integrated physical/chemical and bio-technical LSS and finally to integrated bio-technical regenerative LSS, is suggested. It is shown that at all phases of integrated LSS development, the systems based on physical/chemical processes will be critical for correlating the interfaces between the biological components that process the products obtained in the bio-components, and enabling the vitality of integrated LSS under emergency situations. The interface of integrated LSS with base power supply system is outlined.

Humidity condensate collected and processed in-flight is an important component of a space station drinking water supply. Water recovery systems in general are designed to handle finite concentrations of specific chemical components. Previous analyses of condensate derived from spacecraft and ground sources showed considerable variation in composition. Consequently, an investigation was conducted to collect condensate on the Shuttle while the vehicle was docked to Mir, and return the condensate to Earth for testing. This scenario emulates an early ISS configuration during a Shuttle docking, because the atmospheres intermix during docking and the condensate composition should reflect that. During the STS-89 and STS-91 flights, a total volume of 50 liters of condensate was collected and returned. Inorganic and organic chemical analyses were performed on aliquots of the fluid.