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Disinfection and maintenance of an acceptable level of asepsis in spacecraft potable water delivery systems is a formidable task. The major area of research for this project has been to monitor the formation and growth of biofilm, and biofilm attached microorganisms, on stainless steel surfaces (specifically coupons), and the use of ozone for the elimination of these species in a closed loop system. A number of different techniques have been utilized during the course of a typical run. Scraping and sonication of coupon surfaces with subsequent plating as well as epifluorescence microscopy have been utilized to enumerate biofilm protected Pseudomonas aeruginosa. In addition, scanning electron microscopy is the method of choice to examine the integrity of the biofilm. For ozone determinations, the indigo decolorization spectrophotometric method seems most reliable. Both high- and low-nutrient cultured P. aeruginosa organisms were the target species for the ozone disinfection experiments.

An approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment has been previously described (Reference 1). The Volatile Organics Concentrator (VOC) system was designed for attachment to a gas chromatograph/mass spectrometer (GC/MS) for analysis of the volatile organics in water on Space Station Freedom. The VOC concept utilizes a primary solid sorbent for collection and concentration of the the organics from water, with subsequent transfer using nitrogen gas through a permeation dryer tube to a secondary solid sorbent tube. The secondary solid sorbent is thermally desorbed to a gas chromatograph for separation of the volatiles which are detected using a mass spectrometer.

The Microbial Check Valve (MCV) is used on the Space Shuttle to impart an iodine residual to the drinking water to maintain microbial control. Approximately twenty MCV locations have been identified in the Space Station Freedom design, each with a 90 day life. This translates to 2400 replacement units in 30 years of operation. An in situ regeneration concept has been demonstrated that will reduce this replacement requirement to less than 300 units based on data to date and potentially fewer as further regenerations are accomplished. A totally automated system will result in significant savings in crew time, resupply requirements and replacement costs. An additional feature of the device is the ability to provide a concentrated biocide source (200 mg/liter of I2) that can be used to superiodinate systems routinely or after a microbial upset. This program was accomplished under NASA Contract Number NAS9-18113.

One of the unique aspects of the Space Station is that it will be a totally encapsulated environment and the air and water supplies will be reclaimed for reuse. The Environmental Health System, a subsystem of CHeCS (Crew Health Care System), must monitor the air and water on board the Space Station Freedom to verify that the quality is adequate for crew safety. Specifically, the Water Quality Subsystem will analyze the potable and hygiene water supplies regularly for organic, inorganic, particulate, and microbial contamination. The equipment selected to perform these analyses will be commercially available instruments which will be converted for use on board the Space Station Freedom. Therefore, the commercial hardware will be analyzed to identify the gravity dependent functions and modified to eliminate them.

The process used to identify, select and design an approach to the isolation and concentration of volatile organic compounds from a water sample prior to chemical analysis in a microgravity environment is described. The Volatile Organics Concentrator (VOC) system described in this paper has been designed for attachment to a gas chromatograph/mass spectrometer (GC/MS) for analysis of volatile organics in water on Space Station. In this work, in order to rank the many identified approaches, the system was broken into three critical areas. These were gases, volatile separation from water and water removal/GC/MS interface. Five options involving different gases (or combinations) for potential use in the VOC and GC/MS system were identified and ranked. Nine options for separation of volatiles from the water phase were identified and ranked. Seven options for use in the water removal/GC column and MS interface were also identified and included in overall considerations.

The Space Station Freedom (SSF), with a 30-year projected lifetime and a completely closed-loop Environmental Control and Life Support System (ECLSS), is perhaps the ultimate “Tight Building.” Recognizing the potential for the development of “Tight Building Syndrome” (TBS), and initiating actions to minimize possible TBS occurrences on SSF, requires a multidisciplinary approach that begins with appropriate design concerns and ends with detection and control measures on board SSF. This paper will present a brief summary of current experience with TBS on Earth. While many of the circumstances and methodologies garnered from investigating tight buildings on Earth are similar to those that might be encountered aboard SSF, the Station also presents a unique environment and a special set of constraints which will require an adaptation of previous protocols. Air contamination, including volatile organic compounds and microorganisms, will be the focus of the discussion.

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.

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.

A shower test was conducted recently at NASA-JSC in which waste water was reclaimed and reused. Test subjects showered in a prototype whole body shower following a protocol similar to that anticipated for Space Station. The waste water was purified using reverse osmosis followed by filtration through activated carbon and ion exchange resin beds. The reclaimed waste water was maintained free of microorganisms by using both heat and iodine. This paper discusses the test results, including the limited effectiveness of using iodine as a disinfectant and the evaluation of a Space Station candidate soap for showering. In addition, results are presented on chemical and microbial impurity content of water samples obtained from various locations in the water recovery process.

This paper provides an assessment of functional characteristics needed in the microbial water analysis system being developed for Space Station. Available technology is reviewed with respect to performing microbial monitoring, isolation, or identification functions. An integrated system composed of three different technologies is presented.

Iodine is a flight-proven disinfectant which because of its unique properties, will probably be used on the Space Station and future manned spaceflight applications. However, present knowledge of and experience with iodination is insufficient to assess crew safety when used in conjunction with reclamation or recycle systems, especially if the reclaimed water is consumed.

A microgravity whole body shower (WBS) and a waste water recovery system (WWRS) were used in a closed loop test at the Johnson Space Center. The WWRS process involved chemical pretreatment, phase change distillation and post-treatment. A preprototype Thermoelectric Integrated Hollow Fiber Membrane Evaporation Subsystem (TIMES) was used for distillation after pretreatment and the post-treatment was accomplished with activated carbon, mixed ion exchange resin beds and microbial check valve (MCV) iodine bactericide dispensing units. The purposes of this test were to evaluate a NASA approved Shuttle soap for whole body showering comfort; evaluate the effects of the shower water on the WBS and the TIMES; and evaluate purification qualities of the recovered water in a closed loop operation.