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Biofilms form rapidly on surfaces in contact with the water reclamation systems proposed for long-term space travel. These microbial populations pose a potentially serious hazard to the astronauts, the engineering systems and to the function of plant growth chambers. Human pathogens present in grey water survive for long periods on surfaces, protected against disinfection by the presence of a biofilm matrix. In addition, some of the materials being proposed for use in water reclamation systems for the orbiting space station are highly susceptible to microbial degradation. Both blockage and corrosion can occur as a result of the interactions between the microorganisms and the materials. Chemicals produced by microbial processes during growth on surfaces include both metals and organic toxins. These by-products of metabolic activity are potential hazards to astronaut health and growth of plants being considered as part of the life support system.

Microbial film formation throughout the water reclamation systems proposed for use in the NASA Space Station Freedom poses serious corrosion risks. Choice of materials for construction of these systems must include evaluation of the potential for microbially influenced corrosion. The development of an active and therefore potentially corrosive microbial biofilm on metal surfaces is influenced by the nature of the metal substratum. This has been shown by scanning electron microscopy, isolation and identification of attached bacteria and measurements of biomass and activity. However, these techniques do not allow direct ‘ real-time’ measurement of biofilm formation and subsequent materials degradation. This is necessary to assess the efficacy of biocides and alternative remedial measures. This paper presents potential fouling and corrosion problems associated with water reclamation system design for the NASA orbiting space station.

The purpose of this research is to determine the survival of human pathogens within a water distribution system proposed for the orbiting space station. Initially we investigated the survival of opportunistic pathogenic microorganisms in water under nutrient limiting conditions. A strain of Pseudomonas aeruginosa and two strains of Staphylococcus aureus were grown to mid-log phase then transferred to a starvation regime of sterile deionized water. Cultures were incubated at 10°, 25° or 37° C and were sampled at 24 hr, 1 week, 4 weeks and 6 weeks. The viable cell density was determined by enumerating colony forming units and by directly counting cells stained with acridine orange. Neither of the Staphylococcus strains tested were detected after 1 week of starvation. Our data indicate that Pseudomonas aeruginosa can survive in deionized water at all three temperatures tested at levels exceeding 104 cells per ml.

In 1985, the Man-Systems Division at the Johnson Space Center initiated a program for the development of a whole body shower suitable for operation in a microgravity environment. Supporting this development effort has been a systematic research program focused on four critical aspects of the design (i.e., human factors engineering, biomedical, mechanical, and electrical) and on the interfaces between the whole body shower system and the other systems to be aboard the Space Station (e.g., the water reclamation and air revitalization systems). A series of tests has been conducted to help define the design requirements for the whole body shower. Crew interface research has identified major design parameters related to enclosure configurations, consumable quantities, operation timelines, displays and controls, and shower and cleanup protocols.