Browsing by Author "Rector, Tony"
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Item Design and Delivery of Filter for Removal of Siloxanes from ISS Atmosphere(46th International Conference on Environmental Systems, 2016-07-10) Carter, Donald; Kayatin, Matthew; Wilson, Mark; Perry, Jay; Rector, Tony; Agui, Juan; Gentry, Gregory; Bowman, Elizabeth; Greene, RobertDimethylsilanediol (DMSD) has been identified as a problematic organic on ISS. This contaminant was initially identified in the ISS condensate and in the Water Processor Assembly (WPA) product water in 2010 when the Total Organic Carbon Analyzer (TOCA) detected an increasing TOC trend in the water produced by the WPA. DMSD is not a crew health hazard at the levels observed in the product water, but it may degrade the performance of the Oxygen Generation System (OGS) which uses the WPA product water for electrolysis. In addition, it can prevent the effective operation of the WPA catalytic reactor, and necessitates early replacement of Multifiltration Beds in the WPA. An investigation into the source of DMSD has determined that polydimethylsiloxanes (PDMSs) are hydrolyzing in the Condensing Heat Exchanger (CHX) to form DMSD. PDMSs are prevalent on ISS from a variety of sources, including crew hygiene products, adhesives, caulks, lubricants, and various nonmetallics. These PDMSs are also known to contribute to degradation of the CHX hydrophilic coating, rendering it hydrophobic and therefore adversely affecting its ability to effectively transmit water to the condensate bus. Eventually this loss in performance results in water droplets in the air flow out of the Heat Exchanger, which can lead to microbial growth in the air ducts and can impact the performance of downstream systems. Design concepts have now been developed for removing PDMS in the air stream before it can reach the CHX coating, thus preventing degradation of the coating and decomposition of the PDMS to DMSD. This paper summarizes the current status of the effort to deliver filters to ISS for removing PDMSs from the atmosphere before they can adversely impact the performance of the CHX coating and the WPA.Item Design of an On-orbit Point-of-use Adsorbent Filter for the Extravehicular Mobility Unit Influent Feed-water(47th International Conference on Environmental Systems, 2017) Steele, John; Peyton, Barbara; Rector, Tony; Etter, Dave; Zupan, Doug; Johnston, StephanieTrace film-forming organic contaminants in water have historically been shown to adversely impact EMU (Extravehicular Mobility Unit) Sublimator performance. EMU feed-water quality requirements and strict controls over wetted materials used for feed-water storage and transfer are in place to minimize the risk of introduction of such contaminants. These controls are becoming increasingly difficult to manage for the ISS (International Space Station) mission where the EMU hardware must be repeatedly recharged on-orbit for up to 6-years with feed-water, most of which will be generated or provided from new sources. The supply of water on orbit that was previously transferred from the Space Shuttle to PWR (potable water reservoir) storage containers had previously been under increased scrutiny due to water quality concerns. In one case, EMU hardware (SEMU 3015) feed-water was found to have out-of-family contaminants (polyamides, siloxanes, organic acids) in water supplied from on-orbit stored water. SEMU 3015 experienced Sublimator performance problems on its first EVA which led to the hardware being returned to the ground for refurbishment after only one use The source of the polyamides, siloxanes and organic acids was never determined, but the on-orbit storage containers and transfer lines remain candidates for the source of the contaminants. Efforts are underway to develop an on-orbit scrubber bed for EMU feed-water to circumvent such risks in the future. The scrubber bed is envisioned as being external to the EMU and used to purify all water as it is charged into the EMU feed-water bladders. A sorbent or sorbents would be selected to remove relatively high molecular weight film-forming organic compounds of the type known to adversely impact Sublimator performance. The intent of this paper is to provide a status of efforts to identify the optimal adsorbent material/materials for this application and to detail the design activity underway relative to implementation.Item Design of an On-orbit Point-Of-Use Adsorbent Filter for the Extravehicular Mobility Unit Influent Feed-Water(48th International Conference on Environmental Systems, 2018-07-08) Steele, John; Zupan, Doug; Johnston, Stephanie; Etter, David; Peyton, Barbara; Rector, TonyTrace film-forming organic contaminants in water have historically been shown to adversely impact EMU (Extravehicular Mobility Unit) Sublimator performance. EMU feed-water quality requirements and strict controls over wetted materials used for feed-water storage and transfer are in place to minimize the risk of the introduction of such contaminants. These controls are becoming increasingly difficult to manage for the ISS (International Space Station) mission where the EMU hardware must be repeatedly recharged on-orbit for up to 6-years with feed-water, most of which will be generated or provided from new sources. The supply of water on orbit that was previously transferred from the Space Shuttle to PWR (potable water reservoir) storage containers had previously been under increased scrutiny due to water quality concerns. In one case, EMU hardware (SEMU 3015) feed-water was found to have out-of-family contaminants (polyamides, siloxanes, organic acids) in water supplied from on-orbit stored water. SEMU 3015 experienced Sublimator performance problems on its first EVA which led to the hardware being returned to the ground for refurbishment after only one use The source of the polyamides, siloxanes and organic acids was never determined, but the on-orbit storage containers and transfer lines remain candidates for the source of the contaminants. Efforts are underway to develop, certify and implement an on-orbit Feed-water Supply Filter to circumvent such risks in the future. The EMU Feed-water Supply Filter (EFSF) will be external to the EMU and will be used to purify all water as it is charged into the EMU feed-water bladders. Sorbents were selected to remove relatively high molecular weight film-forming organic compounds of the type known to adversely impact Sublimator performance. This paper provides the status of efforts to develop, certify and implement the EFSF for this application.Item An Evaluation of Technology to Remove Problematic Organic Compounds from the International Space Station Potable Water(44th International Conference on Environmental Systems, 2014-07-13) Rector, Tony; Metselaar, Carol; Peyton, Barbara; Steele, John; Michalek, William; Bowman, Elizabeth; Wilson, Mark; Gazda, Daniel; Carter, LayneSince activation of the Water Processor Assembly (WPA) on the International Space Station (ISS) in November of 2008, there have been three events in which the TOC (Total Organic Carbon) in the product water has increased to approximately 3 mg/L and has subsequently recovered. Analysis of the product water in 2010 identified the primary component of the TOC as dimethylsilanediol (DMSD). An investigation into the fate of DMSD in the WPA ultimately determined that replacement of both Multifiltration (MF) Beds is the solution to recovering product water quality. The MF Beds were designed to ensure that ionic breakthrough occurs before organic breakthrough. However, DMSD saturated both MF Beds in the series, requiring removal and replacement of both MF Beds with significant life remaining. Analysis of the MF Beds determined that the adsorbent was not effectively removing DMSD, trimethylsilanol, various polydimethylsiloxanes, or dimethylsulfone. Coupled with the fact that the current adsorbent is now obsolete, the authors evaluated various media to identify a replacement adsorbent as well as media with greater capacity for these problematic organic contaminants. This paper provides the results and recommendations of this collaborative study.Item Failure Analysis Results and Corrective Actions Implemented for the Extravehicular Mobility Unit 3011 Water in the Helmet Mishap(45th International Conference on Environmental Systems, 2015-07-12) Steele, John; Metselaar, Carol; Peyton, Barbara; Rector, Tony; Rossato, Robert; Macias, Brian; Weigel, Dana; Holder, DonWater entered the Extravehicular Mobility Unit (EMU) helmet during extravehicular activity (EVA) #23 aboard the International Space Station on July 16, 2013, resulting in the termination of the EVA approximately 1-hour after it began. It was estimated that 1.5 liters of water had migrated up the ventilation loop into the helmet, adversely impacting the astronaut’s hearing, vision, and verbal communication. Subsequent on-board testing and ground-based test, tear-down, and evaluation of the affected EMU hardware components determined that the proximate cause of the mishap was blockage of all water separator drum holes with a mixture of silica and silicates. The blockages caused a failure of the water separator degassing function, which resulted in EMU cooling water spilling into the ventilation loop, migrating around the circulating fan, and ultimately pushing into the helmet. The root cause of the failure was determined to be ground-processing shortcomings of the Airlock Cooling Loop Recovery (ALCLR) Ion Filter Beds, which led to various levels of contaminants being introduced into the filters before they left the ground. Those contaminants were thereafter introduced into the EMU hardware on-orbit during ALCLR scrubbing operations. This paper summarizes the failure analysis results along with identified process, hardware, and operational corrective actions that were implemented as a result of findings from this investigation.Item Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator(44th International Conference on Environmental Systems, 2014-07-13) Rector, Tony; Peyton, Barbara M.; Steele, John W.; Maniken, Janice; Bue, Grant C.; Campbell, ColinWater loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a recirculating control loop which had no water quality maintenance. Results show that periodic water maintenance can improve performance of the SWME. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage of this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the evaluation of water recirculation maintenance components was to enhance the robustness of the SWME through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A patented bed design that was developed for a United Technologies Aerospace System military application provided a low pressure drop means for water maintenance in the SWME recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for the ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.Item Process Development for Removal of Siloxanes from ISS Atmosphere(45th International Conference on Environmental Systems, 2015-07-12) Carter, Layne; Perry, Jay; Kayatin, Matthew J.; Wilson, Mark; Gentry, Gregory J.; Bowman, Elizabeth; Monje, Oscar; Rector, Tony; Steele, JohnDimethylsilanediol (DMSD) has been identified as a problematic organic contaminant aboard the ISS. This contaminant was initially identified in humidity condensate and in the Water Processor Assembly (WPA) product water in 2010 when routine water quality monitoring an increasing total organic carbon (TOC) trend in the WPA product water. Although DMSD is not a crew health hazard at the levels observed in the product water, it can degrade the WPA catalytic reactor’s effectiveness and cause early replacement of Multifiltration Beds. DMSD may also degrade the performance of the Oxygen Generation System (OGS) which uses the WPA product water for electrolysis. An investigation into the source of DMSD has determined that polydimethylsiloxane (PDMS) compounds are likely hydrolyzing in the Condensing Heat Exchangers (CHX) to form DMSD. PDMS compounds are prevalent aboard ISS from a variety of sources, including crew hygiene products, adhesives, caulks, lubricants, and various nonmetallic materials. PDMS compounds are also known to contribute to CHX hydrophilic coating degradation by rendering it hydrophobic and therefore adversely affecting its ability to effectively transmit water to the condensate bus. Eventually this loss in performance results in water droplets in the air flow exiting the CHX, which may lead to microbial growth in the air ducts and may impact the performance of downstream systems. Several options have been evaluated to address these concerns. Modifications to the Water Processor Multifiltration Beds and Catalytic Reactor for removal of DMSD were not considered viable, and did not address the issue with PDMS compound degradation of the CHX coating. Design concepts are now in development for removing PDMS compounds from the air stream before they can reach the CHX coating, thus preventing coating degradation and hydrolysis of the PDMS compounds to DMSD. This paper summarizes the current status of the effort to treat these contaminants on ISS.Item Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly(46th International Conference on Environmental Systems, 2016-07-10) Steele, John; Peyton, Barbara; Rector, Tony; Jennings, Mallory; Elms, TheresaDuring EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR (Airlock Cooling Loop Recovery) Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to scrub the failed EMU cooling water loop on-orbit during routine scrubbing operations. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation is being investigation. A simplified means to acquire on-orbit EMU cooling water samples have been designed. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin are undergoing evaluation. These efforts are undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit.Item Status of the Redesign of the Extravehicular Mobility Unit Airlock Cooling Loop Recovery Assembly(47th International Conference on Environmental Systems, 2017) Steele, John; Arnold, Dane; Peyton, Barbara; Rector, Tony; Jennings, MalloryDuring EVA (Extravehicular Activity) 23 aboard the ISS (International Space Station) on 07/16/2013 an episode of water in the EMU (Extravehicular Mobility Unit) helmet occurred, necessitating a termination of the EVA (Extravehicular Activity) shortly after it began. The root cause of the failure was determined to be ground-processing short-comings of the ALCLR Ion Beds which led to various levels of contaminants being introduced into the Ion Beds before they left the ground. The Ion Beds were thereafter used to scrub the failed EMU cooling water loop on-orbit during routine scrubbing operations. The root cause investigation identified several areas for improvement of the ALCLR Assembly which have since been initiated. Enhanced washing techniques for the ALCLR Ion Bed have been developed and implemented. On-orbit cooling water conductivity and pH analysis capability to allow the astronauts to monitor proper operation of the ALCLR Ion Bed during scrubbing operation have been investigated and are being incorporated into the design. A simplified means to acquire on-orbit EMU cooling water samples has been designed as well. Finally, an inherently cleaner organic adsorbent to replace the current lignite-based activated carbon, and a non-separable replacement for the separable mixed ion exchange resin have been selected. These efforts are undertaken to enhance the performance and reduce the risk associated with operations to ensure the long-term health of the EMU cooling water circuit. The intent of this paper is to provide an update of the effort to re-design the ALCLR (Airlock Cooling Loop Recovery) hardware. Last year, this effort was in the early stages of concept development and test which was reported in ICES Paper ICES-2016-221. Those phases are now complete, and the final outcome, as well as plans to build and field the hardware, is reported on.