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At the initial phase of the construction of the international space station (ISS) water supply will be provided by the systems located in the Russian segment. The paper reviews the systems for water recovery from humidity condensate and urine to be incorporated in the Russian segment of the ISS. The similar systems have been successfully operated on the Mir space station. The updates aim at enhancing system cost-effectiveness and reliability. The system for water recovery from humidity condensate (WRS-C) features an added assembly for the removal of organic contaminants to be catalytically oxidized in an air/liquid flow at ambient temperature and pressure. The system for water reclamation from urine (WRS-U) incorporates a new distillation subsystem based on vacuum distillation with a multistage rotary distiller and a vapor compression or thermoelectric heat pump. The updating of the WRS-C system will enable an increase in the multifiltration bed's life at least two fold.

The paper presents the results of ground and flight (on OSS Mir) tests of an updated purification assembly of the WRS-C system outfitted with a filter-reactor. The tests have proved that the filter-reactor oxidizes effectively basic organic contaminants in humidity condensate including ethyleneglycol to ones that easily undergo sorption, enables the operation of the recovery system in the event of an off-design increase in organic contaminants in condensate and significantly improves the lifetime of the purification assembly. The data obtained confirm a wise selection of the purification assembly hardware for the system for water recovery from humidity condensate WRS-CM for the ISS service module.

The paper deals with possible performance enhancement of the system for water reclamation from urine based on a principle of atmospheric distillation. It is shown by way of example using the system operating on Mir that the introduction of heat energy recuperation, an increase in heat-and-mass transfer efficiency on evaporation and the optimization of the air flowrate in the distillation cycle allow a rise in the capacity of the distillation assembly and a reduction in specific energy. The system outfitted with a rotary evaporator/separator and a thermoelectric heat pump is reviewed. The design and experimental data verify the feasibility and benefits of the system updating.

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.

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.

Development of closed life support systems for water recovery, oxygen generation and food processing is achievable in the future. However, currently the possibility of partial reproduction of food components from metabolic products and biocomplex waste should be taken into account when advanced life support system development is under consideration. Studies on carbohydrate synthesis from products of life are of particular interest because carbohydrates hold the first place in terms of mass in the food. The paper discusses possible ways of carbohydrate synthesis by physical/chemical means. Separate stages of a carbohydrate synthesis process are considered.

The paper deals with some aspects and results of research in major processes and hardware of a system for hygiene waste water recovery and its architecture concepts. A principal system schematic and its functions on Mir space station are presented. It is shown that physico-chemical means ensure cost-effective recovery with minimum energy demand and resupply which is particulary important for long-duration space missions.