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Twenty-nine recycled water, eight stored (ground-supplied) water, and twenty-eight humidity condensate samples were collected on board the Mir Space Station during the Phase One Program (1995-1998). These samples were analyzed to determine potability of the recycled and ground-supplied water, to support the development of water quality monitoring procedures and standards, and to assist in the development of water reclamation hardware. This paper describes and summarizes the results of these analyses and lists the lessons learned from this project. Results show that the recycled water and stored water on board Mir, in general, met NASA, Russian Space Agency (RSA), and U.S. Environmental Protection Agency (EPA) standards.

The development of a spectrophotometric analyzer for use on water samples in microgravity environments is discussed. The instrument is constructed around a commercial spectrophotometer, the Hewlett-Packard HP8453, with a separate turbidimetric analyzer, here a modified Hach 2100P ratio turbidimeter. Flow-through sample cells were constructed for each instrument to support microgravity use and sample deaeration. Spectrophotometric analyses on aqueous samples on orbit are sensitive to the presence of undissolved gases in the samples. In a micro-g environment, free gas in samples can and does remain suspended, clouding the mixture and interfering with spectral optical density measurements. This paper discusses the design of a spectrophotometric analyzer, with particular emphasis on the merits of two approaches to eliminating free gas interferences in on-orbit water analyses: hyperbaric gas redissolution and deaeration across a hydrophobic membrane.

Iodine is the disinfectant used in U.S. spacecraft potable water systems. Recent long-term testing on human subjects has raised concerns about excessive iodine consumption. Efforts to reduce iodine consumption by Shuttle crews were initiated on STS-87, using hardware originally designed to deiodinate Shuttle water prior to transfer to the Mir Space Station. This hardware has several negative aspects when used for Shuttle galley operations, and efforts to develop a practical alternative were initiated under a compressed development schedule. The alternative Low Iodine Residual System (LIRS) was flown as a Detailed Test Objective on STS-95. On-orbit, the LIRS imparted an adverse taste to the water due to the presence of trialkylamines that had not been detected during development and certification testing. A post-flight investigation revealed that the trialkylamines were released during gamma sterilization of the LIRS resin materials.

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.

Archival sampling of potable water and condensate for ground laboratory analysis has been an important part of the Shuttle-Mir program because of coolant leaks and other events on Mir that have affected water quality. We report here the development of and preliminary results from a novel device for single phase humidity condensate collection at system pressures. The sampler consists of a commercial-off-the-shelf Teflon® bladder and a custom reinforced Nomex® restraint that is sized properly to absorb the stress of applied pressures. A plastic Luer-Lock disconnect, with poppet actuated by a mating Luer-Lock fitting, prevents the contents from being spilled during transport. In principle, a sampler of any volume can be designed. The empty mass of the reusable one-liter sampler is only 63 grams. Several designs were pressure tested and found to withstand more than 3 atmospheres well in excess of typical spacecraft water or wastewater system pressures.

On the International Space Station (ISS), atmospheric humidity condensate and other waste waters will be recycled and treated to produce potable water for use by the crews. Space Station requirements include an on-orbit capability for real-time monitoring of key water quality parameters, such as total organic carbon (TOC), total inorganic carbon (TIC), total carbon (TC), pH, and conductivity, to ensure that crew health is protected during consumption of reclaimed water. The Crew Health Care System (CHeCS) for ISS includes an analyzer that has been designed to meet this requirement. The analyzer is adapted from commercially successful technology, and it measures TOC and TIC throughout the range from 1 to 50,000 μg/L, and TC from 1 to 100,000 μg/L. It measures pH between 2.0 and 12.0 pH units, and conductivity from 0.1 to 300 μmho/cm. The analyzer is scheduled for launch to ISS on mission 2A.1.

On the International Space Station (ISS), atmospheric humidity condensate and other waste waters will be recycled and treated to produce potable water for use by the crews. Space station requirements include an on-orbit capability for real-time monitoring of key water quality parameters, such as total organic carbon, total inorganic carbon, total carbon, pH, and conductivity, to ensure that crew health is protected for consumption of reclaimed water. The Crew Health Care System for ISS includes a total organic carbon (TOC) analyzer that is currently being designed to meet this requirement. As part of the effort, a spacecraft TOC analyzer was developed to demonstrate the technology in microgravity and mitigate risks associated with its use on station. This analyzer was successfully tested on Shuttle during the STS-81 mission as a risk mitigation experiment. A total of six ground-prepared test samples and two Mir potable water samples were analyzed in flight during the 10-day mission.

The primary source of potable water planned for the International Space Station will be generated from the reclamation of humidity condensate, urine, and hygiene waters. It is vital to crew health and performance that this reclaimed water be safe for human consumption, and that health risks associated with recycled water consumption be identified and quantified. Only recently has data been available on the chemical constituents in reclaimed waters generated in microgravity. Results for samples collected during Mir-21 reveal that both the reclaimed water and stored water are of potable quality, although the samples did not meet U.S. standards for total organic carbon (TOC), total phenols, and turbidity.

This report describes the first two parts of a three-phase project to develop and test a spacecraft-compatible capillary electrophoresis (CE) instrument. This instrument is designed to monitor the quality of recycled potable water aboard spacecraft such as the International Space Station. Phase I involved selecting and validating methods for low mass-to-charge ratio (m/z) cations and anions by using a slightly modified commercial CE instrument as a model. The analytical performance of several published CE methods was assessed for their ability to detect targeted anions and cations listed in a NASA water quality standard. Direct and indirect UV absorption detection at a single wavelength (214 nm) was used, and separation selectivity and sensitivity were optimized at the expense of analysis time. Phase II focused on building a breadboard CE instrument and flight-testing it on NASA's KC-135 parabolic aircraft.

To satisfy a requirement to supply water to Mir station, a process for treating iodinated water on the Shuttle was developed and implemented. The treatment system consists of packed columns for removing iodine and a syringe-based injection system for adding ionic silver, the biocide used in Mir water. Technical and potable grade water is produced and transferred in batches using collapsible 44-liter contingency water containers (CWCs). Silver is added to the water via injection of a solution from preloaded syringes. Minerals are also added to water destined for drinking. During the previous four Shuttle-Mir docking missions a total of 2781 liters (735 gallons) of water produced by the Shuttle fuel cells was processed using this method and transferred to Mir. To verify the quality of the processed water, samples were collected during flight and returned for chemical analysis.

The Water and Food Analytical Laboratory, at the Johnson Space Center is developing an alternative to EPA Method 625 for analyzing semivolatile organic compounds in water. The current EPA method uses liquid-liquid extraction. The alternative method being developed differs in the sample preparation phase by replacing gravity-dependent liquid-liquid extraction with solid phase extraction (SPE). The ultimate goal is to incorporate the optimum SPE conditions into an automated sample preparation process. The method shows promise with regard to anticipated polar compounds. Fourteen SPE resins and nine elution solvents were compared. For typical analytes encountered by our laboratory, a styrene-divinylbenzene SPE resin and an elution solvent mixture of methylene chloride and ethyl ether were found to give the highest extraction recoveries. A study is in progress to remove water from the extracts before GC/MS analysis.

An important milestone in the ongoing effort by NASA to develop and refine closed-loop water recycling systems for human space flight was reached during the summer of 1996 with the successful completion of Phase II of the Lunar Mars Life Support Testing Program at Johnson Space Center. Part of Phase II involved testing a water-recycling system in a closed test chamber continuously occupied by four human subjects for thirty days. The Phase II crew began the test with a supply of water that had been processed and certified for human use. As the test progressed, humidity condensate, urine, and wastewater from personal hygiene and housekeeping activities were reclaimed and reused several times. Samples were collected from various points in the reclamation process during the thirty day test. The data verified the water-processing hardware can reliably remove wastewater contaminants and produce reclaimed water that meets NASA standards for hygiene- and potable-quality water.

The ability to aseptically remove samples and products, and the capability for addition of materials to sterile or otherwise microbially susceptible systems have always been compromised by the lack of a reliable means of sterilizing the mating fixtures. Cultures of mammalian cells are particularly vulnerable to microbial contamination due to the complexity of nutrient media and the lengthy periods required for cell growth. The Microwave Sterilizable Access Port has been developed to overcome this limitation. The system consists of three primary components: a microwave power source, a combined sterilization chamber/in-line valve port assembly, and a specimen transfer interface. Microwave energy is transmitted via coaxial cable to a small pressurized chamber that serves as a sterile transition between the surrounding environment and the system during transfer of materials.

Potable- and hygiene-quality water will be supplied to crews on the International Space Station through the recovery and purification of spacecraft wastewaters, including humidity condensate, urine, and wash water. Contaminants released into the cabin air from human metabolism, hardware offgassing, flight experiments, and routine operations will be present in spacecraft humidity condensate; normal constituents of urine and bathing water will be present in urine and untreated wash water. This report describes results from detailed analyses of Mir reclaimed potable water, ground-supplied water, and humidity condensate. These results are being used to develop and test water recycling and monitoring systems for the International Space Station (ISS); to evaluate the efficiency of the Mir water processors; and to determine the potability of the recycled water on board.

A Total Organic Carbon (TOC) Analyzer has been developed for a Life Sciences Risk Mitigation Flight Experiment to be conducted on Spacehab and the Russian space station, Mir. Initial launch is scheduled for December 1996 (flight STS-81). The analyzer will be tested on the Orbiter in the Spacehab module, including when the Orbiter is docked at the Mir space station. The analyzer is scheduled to be launched again in May 1997 (STS-84) when it will be transferred to Mir. During both flights the analyzer will measure the quality of recycled and ground-supplied potable water on the space station. Samples will be archived for later return to the ground, where they will be analyzed for comparison to in-flight results. Water test samples of known composition, brought up with the analyzer, also will be used to test its performance in microgravity. Ground-based analyses of duplicates of those test samples will be conducted concurrently with the in-flight analyses.

On the International Space Station (ISS), humidity condensate will be collected from the atmosphere and treated by multifiltration to produce potable water for use by the crews. Ground-based development tests have demonstrated that multifiltration beds filled with a series of ion-exchange resins and activated carbons can remove many inorganic and organic contaminants effectively from wastewaters. As a precursor to the use of this technology on the ISS, a demonstration of multifiltration treatment under microgravity conditions was undertaken. On the Space Shuttle, humidity condensate from cabin air is recovered in the atmosphere revitalization system, then stored and periodically vented to space vacuum. A Shuttle Condensate Adsorption Device (SCAD) containing sorbent materials similar to those planned for use on the ISS was developed and flown on STS-68 as a continuation of DSO 317, which was flown initially on STS-45 and STS-47.

A computer interfaced instrument designed to quantify ammonia and other nitrogenous species that are important regenerative life support water quality parameters is described in this paper. Measurements can be made either discretely by Flow Injection Analysis (FIA) or continuously using a split stream from a process flow. The monitor exhibits a predictable quadratic response for ammonia injections between 10 μg/L to 20 mg/L with a response time less than six minutes. A full description of the ammonia monitor's response to a variety of challenge solutions including real sewage treatment plant effluent is given. In addition, the response time characteristics, the effects of temperature, and interferences are described.

One of the proposed methods for monitoring the microbial quality of the water supply aboard the International Space Station is membrane filtration. We adapted this method for space flight by using an off-the-shelf filter unit developed by Millipore. This sealed unit allows liquid to be filtered through a 0.45 μm cellulose acetate filter that sits atop an absorbent pad to which growth medium is added. We combined a tetrazolium dye with R2A medium to allow microbial colonies to be seen easily, and modified the medium to remain stable over 70 weeks at 25°C. This hardware was assembled and tested in the laboratory and during parabolic flight; a modified version was then flown on STS-66. After the STS-66 mission, a back-up plastic syringe and an all-metal syringe pump were added to the kit, and the hardware was used successfully to evaluate water quality aboard the Russian Mir space station.

Controlling microbial growth and biofilm formation in spacecraft water-distribution systems is necessary to protect the health of the crew. Methods to decontaminate the water system in flight may be needed to support long-term missions. We evaluated the ability of iodine and ozone to kill attached bacteria and remove biofilms formed on stainless steel coupons. The biofilms were developed by placing the coupons in a manifold attached to the effluent line of a simulated spacecraft water-distribution system. After biofilms were established, the coupons were removed and placed in a treatment manifold in a separate water treatment system where they were exposed to the chemical treatments for various periods. Disinfection efficiency over time was measured by counting the bacteria that could be recovered from the coupons using a sonication and plate count technique. Scanning electron microscopy was also used to determine whether the treatments actually removed the biofilm.

The objective of this study was to investigate combining GC/MS and CE methods to allow sub-mg/L levels of organic acids to be determined in various water samples. This study also served as a basis for evaluating these instruments for in-flight spacecraft water-quality monitoring and to help determine the modifications needed to convert terrestrial hardware for use in microgravity environments. This paper reports on current GC/MS and CE method development and data generated from some recent spacecraft-related water samples. Plans for further method development are also discussed.