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Space Station Freedom (SSF) will be operational for up to 30 years with missions lasting up to 180 days. Because of the need for large amounts of potable and hygiene water for the crews, it will not be practical to supply water from the ground (as was done for Skylab) or to generate water from fuel cells (as is done for the Shuttle). Hence, waste and metabolic waters will be reclaimed and recycled in SSF. Because of the unique nature of the water sources and the closed loop recycling processes, providing safe water will be a challenging task. Developing a program for the verification of SSF water quality to ensure crew health is the responsibility of NASA's Medical Sciences Division at the Johnson Space Center (JSC). This program is being implemented through the Environmental Health System (EHS). This paper will describe the strategy for the development of water quality criteria and standards, and the associated monitoring requirements.

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 lessons of past and present manned space programs are clear. Successful design and operation of a spacecraft water system is contingent upon consideration of traditional sanitary engineering principles in the context of unique mission requirements. However, the aerospace solution to the traditional terrestrial problem often requires an innovative design approach to succeed in the spacecraft environment. Future long duration space missions will require the same attention to basic principles, the same degree of innovation, and an extra measure of caution, because of the lack of terrestrial experience with direct human reuse of reclaimed water.

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.

Potable water for the Shuttle orbiter is generated as a by-product of electricity production by the fuel cells. Water from the fuel cells flows through a Microbial Check Valve (MCV), which releases biocidal iodine into the water before it enters one of four storage tanks. Potable water is dispensed on-orbit at the rehydration unit of the galley. Due to crew health concerns, iodine removal hardware is installed in the chilled water inlet line to the galley to remove the iodine from the potable water before it is consumed by the crew. The Shuttle water system is sampled to ensure water quality is maintained during all operational phases from the disinfection of the ground servicing equipment through the completion of each mission. This paper describes and summarizes the Shuttle water quality requirements, the servicing of the Shuttle water system, the collection and analysis of Shuttle water samples, and the results of the analyses.

The crews of Expeditions 12 and 13 aboard the International Space Station (ISS) continued to rely on potable water from two different sources, regenerated humidity condensate and Russian ground-supplied water. The Space Shuttle launched twice during the 12-months spanning both expeditions and docked with the ISS for delivery of hardware and supplies. However, no Shuttle potable water was transferred to the station during either of these missions. The chemical quality of the ISS onboard potable water supplies was verified by performing ground analyses of archival water samples at the Johnson Space Center (JSC) Water and Food Analytical Laboratory (WAFAL). Since no Shuttle flights launched during Expedition 12 and there was restricted return volume on the Russian Soyuz vehicle, only one chemical archive potable water sample was collected with U.S. hardware and returned during Expedition 12. This sample was collected in March 2006 and returned on Soyuz 11.

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.

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.

Microbial proliferation in the STS potable water system is prevented by maintaining a 2-5 ppm iodine residual. The iodine is added to fuel cell water by an iodinated ion exchange resin in the Microbial Check Valve (MCV). Crew comments indicated excessive iodine in the potable water. To better define the problem, a method of in-flight iodine analysis was developed. Inflight analysis during STS-30 and STS-28 indicated iodine residuals were generally in the 9-13 ppm range. It was determined that the high iodine residual was caused by MCV influent temperatures in excess of 120 °F. This is well above the MCV operating range of 65-90 °F. The solution to this problem was to develop a resin suitable for the higher temperatures. Since 8 months were required to formulate a MCV resin suitable for the higher temperatures, a temporary solution was necessary. Two additional MCV's were installed on the chilled and ambient water lines leading into the galley to remove the excess iodine.

The water supply for the International Space Station (ISS) consists partially of excess fuel-cell water that is treated on the Shuttle and stored on ISS in 44 L collapsible Contingency Water Containers (CWCs). Iodine is removed from the source water, and silver biocide and mineral concentrates are added by the crewmember while the CWCs are filled. Potable (mineralized) CWCs are earmarked for drinking and food hydration, and technical (non-mineralized) CWCs are reserved for waste system flushing and electrolytic oxygen generation. Representative samples are collected in Teflon® bags and returned to Earth for chemical analysis. The parameters typically measured include pH, conductivity, total organic carbon, iodine, silver, calcium, magnesium, fluoride, trace metals, formate and alcohols. The Nylon monomer caprolactam is also measured and tracked since it is known to leach slowly out of the plastic CWC bladder material.

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.

We are developing a drinking water test kit based on colorimetric-solid phase extraction (C-SPE) for use onboard the International Space Station (ISS) and on future Lunar and/or Mars missions. C-SPE involves measuring the change in diffuse reflectance of indicator disks following their exposure to a water sample. We previously demonstrated the effectiveness of C-SPE in measuring iodine in microgravity. This analytical method has now been extended to encompass the measurement of total I (i.e., iodine, iodide, and triiodide). This objective was accomplished by introducing an oxidizing agent to convert iodide and triiodide to iodine, which is then measured using the indicator disks previously developed for iodine. We report here the results of a recent series of C-9 microgravity tests of this method. The results demonstrate that C-SPE technology is poised to meet the total I monitoring requirements of the international space program.

Phase separation is one of the most significant obstacles encountered during the development of analytical methods for water quality monitoring in spacecraft environments. Removing air bubbles from water samples prior to analysis is a routine task on earth; however, in the absence of gravity, this routine task becomes extremely difficult. This paper details the development and initial ground testing of liquid metering centrifuge sticks (LMCS), devices designed to collect and meter a known volume of bubble-free water in microgravity. The LMCS uses centrifugal force to eliminate entrapped air and reproducibly meter liquid sample volumes for analysis with Colorimetric Solid Phase Extraction (C-SPE). Previous flight experiments conducted in microgravity conditions aboard the NASA KC-135 aircraft demonstrated that the inability to collect and meter a known volume of water using a syringe was a limiting factor in the accuracy of C-SPE measurements.

Collapsible bladder tanks called Contingency Water Containers (CWCs) have been used to transfer water from the Shuttle to the Mir and the International Space Station (ISS). Because their use as potable water storage on the ISS is planned for years, efforts are underway to improve the containers, including the evaluation of new materials. Combitherm®, a multi-layer plastic film, is a material under evaluation for use as the CWC bag material. It consists of layers of linear low density polyethylene, ethylene-vinyl alcohol copolymer, nylon, and a solvent- free adhesive layer. Long term studies of the quality of water stored in Combitherm bladders indicate a gradual but steady increase in the total organic carbon value. This suggests a leaching or breakdown of an organic component of the Combitherm.

Liquid Chromatography / Mass Spectrometry / Mass Spectrometry (LC/MS/MS) is a powerful technique for identifying unknown non-volatile organic compounds dissolved in liquids. One type of LC/MS/MS that is gaining popularity is quadrupole-time-of-flight (QqTOF) mass spectrometry. This technique is now in use at the Johnson Space Center for identification of unknown nonvolatile organics in water samples from the space program. An example of the successful identification of an unknown peak in U.S. Lab Condensate is reviewed in detail in this paper. Each step of the procedure is described in the identification of triethylene glycol mono-n-butyl ether (TGBE) as the unknown analyte. The advantages of time-of-flight instrumentation are demonstrated through this example as well as the strategy employed in using time-of-flight data to identify unknowns. The use of the instrument for quantitative analysis is also demonstrated.

The Crew Health Care System (CHeCS) is responsible for providing environmental monitoring to protect crew health, including in-flight chemical water quality analysis. To meet this objective, Total Organic Carbon Analyzer (TOCA) Serial Number (SN) 1002 was launched to the International Space Station (ISS) in April of 2001 as part of the CHeCS hardware. Since that time it has been used to evaluate the quality of the potable water supplies consisting of reprocessed atmospheric condensate water, Shuttle-transferred water, and ground-supplied water. Potable water is available for crew use from the Service Module System for Regeneration of Water from Condensate (SRV-K) galley hot and warm ports and the Stored Potable Water System (SVO-ZV) port. Potable water samples are periodically collected from each of these ports for in-flight analysis with the TOCA.

Potable water supplies onboard the International Space Station (ISS) include both reclaimed water from treatment of atmospheric humidity condensate and stored water that is either Shuttle-transferred or ground-supplied. Space station medical operations requirements call 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 from unsafe drinking water. A Total Organic Carbon Analyzer (TOCA) designed to meet these requirements was developed as part of the Crew Health Care System and launched to the ISS in April of 2001. The initial design of the ISS TOCA was previously presented at this conference in 1998. The current design of the instrument includes an improved reagent system and upgraded software to enhance accuracy through the capability to measure organic contamination of the reagents and correct analytical results.

Ever since the first crew arrived at the International Space Station (ISS), archival potable water samples have been collected and returned to the ground for detailed chemical analysis in order to verify that the water supplies onboard are suitable for crew consumption. The Columbia tragedy, unfortunately, has had a dramatic impact on continued ISS operations. A major portion of the ISS water supply had previously consisted of Shuttle-transferred water. The other two remaining sources of potable water, i.e., reclaimed humidity condensate and Russian-launched ground water, are together insufficient to maintain 3-person crews. The Expedition 7 crew launched in April of 2003 was, therefore, reduced from three to two persons. Without the Shuttle, resupply of ISS crews and supplies is dependent entirely on Russian launch vehicles (Soyuz and Progress) with severely limited up and down mass.

The International Space Station (ISS) drinking water supply consists of water recovered from humidity condensate, water transferred from Shuttle, and groundwater supplied from Russia. The water is dispensed from both the stored water dispensing system (SVO-ZV) and the condensate recovery system (SRV-K) galley. Teflon bags are used periodically to collect potable water samples, which are then transferred to Shuttle for return to Earth. The results from analyses of these samples are used to monitor the potability of the drinking water on board and evaluate the efficiency of the water recovery system. This report provides results from detailed analyses of samples of ISS recovered potable water, Shuttle-supplied water, and ground-supplied water taken during ISS Expeditions 4 and 5. During Expedition 4, processing of U.S. Lab condensate through the Russian condensate recovery system was initiated. Results indicate water recovered from both Service Module and U.S.

During the twelve month period comprising Expeditions 10 and 11, the chemical quality of the potable water onboard the International Space Station (ISS) was verified through the return and ground analysis of water samples. The two-man Expedition 10 crew relied solely on Russian-provided ground water and reclaimed cabin humidity condensate as their sources of potable water. Collection of archival water samples with U.S. hardware has remained extremely restricted since the Columbia tragedy because of very limited return volume on Russian Soyuz vehicles. As a result only two such samples were collected during Expedition 10 and returned on Soyuz 9. The average return sample volume was only 250 milliliters, which limited the breadth of chemical analysis that could be performed. Despite the Space Shuttle vehicle returning to flight in July 2005, only two potable water samples were collected with U.S. hardware during Expedition 11 and returned on Shuttle flight STS-114 (LF1).