Characterization of Condensate from the Research Animal Holding Facility (RAHF) 941506

Life Sciences research on Space Station will utilize rats to study the effects of the microgravity environment on mammalian physiology and to develop countermeasures to those effects for the health and safety of the crew. The animals will produce metabolic water which must be reclaimed to minimize logistics support. The condensate from the Research Animal Holding Facility (RAHF) flown on Spacelab Life Sciences-2 (SLS-2) in October 1993 was used as an analog to determine the type and quantity of constituents which the Space Station (SS) water reclamation system will have to process. The most significant organics present in the condensate were 2-propanol, glycerol, ethylene glycol, 1,2-propanediol, acetic acid, acetone, total proteins, urea and caprolactam while the most significant inorganic was ammonia. Microbial isolates included Xanthomonas, Sphingobacterium, Pseudomonas, Penicillium, Aspergillus and Chrysosporium. Previous testing of the SS Water Processor has shown that all chemical and microbial contaminants present in the RAHF condensate can be adequately removed.

ONE OF THE PRIMARY USES of the Space Station will be to investigate the effect of the microgravity environment on biological processes. This will necessitate the maintenance of both plants and animals on the Space Station (SS). In the Shuttle program rats are housed either in the Animal Enclosure Module (AEM) or in the Research Animal Holding Facility (RAHF). In both systems, the urine produced by the animals is adsorbed onto a filter in the waste tray and the water is evaporated from the urine by a stream of air flowing continuously through the filters. In the AEM the evaporated water is exhausted into the cabin while in the RAHF, the evaporated water is condensed and stored in a condensate bag (1). The condensed water is then returned to Earth in the bags. Missions using either the AEM or RAHF are typically less than fourteen days and house comparatively few animals (5 in the AEM and 24 in each RAHF) so the volume of condensate is relatively small. For Space Station, new rodent habitats will be built as part of the Centrifuge Facility (CF) (2) with missions as long as 90 days and housing as many as 72 rats. The Phase A concept for the Centrifuge Facility rodent habitats (3) uses a condensate system similar to that in the RAHF where the evaporated urine is condensed and collected. However, because of the longer mission duration and larger animal population planned for Space Station, a much larger volume of condensate will be collected than in the Shuttle missions. The Centrifuge Facility Project Office (CFPO) has requested that the condensate be processed by the SS Water Processor. Reclamation of the condensate by the Water Processor for reuse is preferable to storage and return of the condensate to Earth because it will significantly reduce the logistics support required for the maintenance of the animals. Because the Centrifuge Facility Phase A hardware design concept for condensate recovery and storage is similar to the RAHF design, it was felt that condensate from the RAHF would provide a valid model for determining if the condensate could be reclaimed by the SS Water Processor. Accordingly, ARC and MSFC have been involved in a cooperative effort to collect RAHF condensate from the October 1993 SLS-2 mission, analyze the condensate for chemical, physical, and microbial constituents and assess the impact on the Water Processor of processing the condensate.