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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

To Biocide or not to Biocide? Exploring the "No Biocide" Option in Spacecraft Potable Water Systems

Residual biocide has been used to protect against microbial growth in spacecraft potable water systems since the Gemini program. Iodine, the biocide currently used on the International Space Station (ISS) has a long history of use but presents a few challenges for exploration: it must be removed using a consumable absorbent before crew consumption and is known to lose its biocidal concentration due to interactions with wetted components, especially during periods of dormancy. Biocidal silver is being considered for exploration missions as it is safe for crew consumption, but it too has challenges with proper material design to maintain sufficient disinfection residuals. An idea proposed by some in the Environmental Control and Life Support System (ECLSS) community has been that the biocide does not provide a true barrier against microbial growth, and therefore, perhaps the challenges of maintaining a residual biocide in the system could be best overcome by removing the biocide altogether. In this argument, they point to the regenerative water treatment system on the ISS which produces high purity water that theoretically meets the microbiological requirements before the iodine is added. Exploration water processing systems are expected to have similar water processing capabilities. This paper will discuss the role that residual biocide may play in controlling microbial growth and presents perspectives on the potential risks associated with removing it from exploration water systems.

biocide↗
NASA NTRSDate not supplied

To Biocide or not to Biocide? Exploring the "No Biocide" Option in Spacecraft Potable Water Systems

Residual biocide has been used to protect against microbial growth in spacecraft potable water systems since the Gemini program. Iodine, the biocide currently used on the International Space Station (ISS) has a long history of use but presents a few challenges for exploration: it must be removed using a consumable absorbent before crew consumption and is known to lose its biocidal concentration due to interactions with wetted components, especially during periods of dormancy. Biocidal silver is being considered for exploration missions as it is safe for crew consumption, but it too has challenges with proper material design to maintain sufficient disinfection residuals. An idea proposed by some in the Environmental Control and Life Support System (ECLSS) community has been that the biocide does not provide a true barrier against microbial growth, and therefore, perhaps the challenges of maintaining a residual biocide in the system could be best overcome by removing the biocide altogether. In this argument, they point to the regenerative water treatment system on the ISS which produces high purity water that theoretically meets the microbiological requirements before the iodine is added. Exploration water processing systems are expected to have similar water processing capabilities. This paper will discuss the role that residual biocide may play in controlling microbial growth and presents perspectives on the potential risks associated with removing it from exploration water systems.

biocide↗
NASA NTRSDate not supplied

To Biocide or Not to Biocide? Exploring the "No Biocide" Option in Spacecraft Potable Water Systems

Residual biocide has been used to protect against microbial growth in spacecraft potable water systems since the Gemini program. Iodine, the biocide currently used on the International Space Station (ISS) has a long history of use but presents a few challenges for exploration: it must be removed using a consumable absorbent before crew consumption and is known to lose its biocidal concentration due to interactions with wetted components, especially during periods of dormancy. Biocidal silver is being considered for exploration missions as it is safe for crew consumption, but it too has challenges with proper material design to maintain sufficient disinfection residuals. An idea proposed by some in the Environmental Control and Life Support System (ECLSS) community has been that the biocide does not provide a true barrier against microbial growth, and therefore, perhaps the challenges of maintaining a residual biocide in the system could be best overcome by removing the biocide altogether. In this argument, they point to the regenerative water treatment system on the ISS which produces high purity water that theoretically meets the microbiological requirements before the iodine is added. Exploration water processing systems are expected to have similar water processing capabilities. This paper will discuss the role that residual biocide may play in controlling microbial growth and presents perspectives on the potential risks associated with removing it from exploration water systems.

biocide↗
NASA NTRSDate not supplied

To Biocide or Not to Biocide? Exploring the "No Biocide" Option in Spacecraft Potable Water Systems

Residual biocide has been used to protect against microbial growth in spacecraft potable water systems since the Gemini program. Iodine, the biocide currently used on the International Space Station (ISS) has a long history of use but presents a few challenges for exploration: it must be removed using a consumable absorbent before crew consumption and is known to lose its biocidal concentration due to interactions with wetted components, especially during periods of dormancy. Biocidal silver is being considered for exploration missions as it is safe for crew consumption, but it too has challenges with proper material design to maintain sufficient disinfection residuals. An idea proposed by some in the Environmental Control and Life Support System (ECLSS) community has been that the biocide does not provide a true barrier against microbial growth, and therefore, perhaps the challenges of maintaining a residual biocide in the system could be best overcome by removing the biocide altogether. In this argument, they point to the regenerative water treatment system on the ISS which produces high purity water that theoretically meets the microbiological requirements before the iodine is added. Exploration water processing systems are expected to have similar water processing capabilities. This paper will discuss the role that residual biocide may play in controlling microbial growth and presents perspectives on the potential risks associated with removing it from exploration water systems.

biocide↗
NASA NTRS2008

Crew Exploration Vehicle (CEV) Potable Water System Verification Description

The Crew Exploration Vehicle (CEV), also known as Orion, will ferry a crew of up to six astronauts to the International Space Station (ISS), or a crew of up to four astronauts to the moon. The first launch of CEV is scheduled for approximately 2014. A stored water system on the CEV will supply the crew with potable water for various purposes: drinking and food rehydration, hygiene, medical needs, sublimation, and various contingency situations. The current baseline biocide for the stored water system is ionic silver, similar in composition to the biocide used to maintain quality of the water transferred from the Orbiter to the ISS and stored in Contingency Water Containers (CWCs). In the CEV water system, the ionic silver biocide is expected to be depleted from solution due to ionic silver plating onto the surfaces of the materials within the CEV water system, thus negating its effectiveness as a biocide. Since the biocide depletion is expected to occur within a short amount of time after loading the water into the CEV water tanks at the Kennedy Space Center (KSC), an additional microbial

Peterson, Laurie↗
NASA NTRS1975

Potable water recovery for spacecraft application by electrolytic pretreatment/air evaporation

A process for the recovery of potable water from urine using electrolytic pretreatment followed by distillation in a closed-cycle air evaporator has been developed and tested. Both the electrolytic pretreatment unit and the air evaporation unit are six-person, flight-concept prototype, automated units. Significantly extended wick lifetimes have been achieved in the air evaporation unit using electrolytically pretreated, as opposed to chemically pretreated, urine feed. Parametric test data are presented on product water quality, wick life, process power, maintenance requirements, and expendable requirements.

Wells, G. W.↗
NASA NTRS1989

Electrochemical control of iodine disinfectant for space transportation system and space station potable water

An electrochemical microbial check valve method (EC-MCV) for controlling the iodine disinfectant in potable water (PW) for NASA's space operations was proposed. The factors affecting the design and performance of the unit were analyzed. This showed that it would be feasible to construct a recyclable unit in a small volume that will operate in either an iodine removal or addition mode. The EC-MCV should remove active iodine species rapidly from PW, but the rapid delivery rates at end-use may make complete removal of excess I(-) difficult under some conditions. Its performace change with AgI buildup needs to be investigated, as this controls the time for recycling the unit. The EC-MCV has advantages over the passive microbial check valve (MCV) method currently in use, as it would allow precise control of the I2 level and would not introduce excess I(-) to the water. The presence of oxygen in the EC-MCV needs to be investigated as it could affect the efficiency of I2 addition and excess I(-) removal.

Geer, Richard D.↗
NASA NTRS2024

Graphene-Based Filtration Media for Spacecraft Potable Water Systems: An Early Investigation

Graphene-based materials have allowed fundamental advances in fields such as energy storage, electronics development, material science, optics, medicine, and water processing due to their unique two-dimensional structure, mechanical robustness, large surface, and high conductivity. However, little to no effort has been devoted to exploiting and studying these materials to develop new water technologies suited for spacecraft applications. One such application is the potential use of graphene-based materials as filtration media for reclaimed water. Therefore, studying the adsorptive performance of these new materials becomes crucial in identifying the opportunity to replace/upgrade state-of-the-art filtration media currently used in space vehicles with water recovery capability; especially if consumable requirements can be lessened as a result of extended filtration capacity. This early Life-Support-Systems investigation pioneers in graphene research by testing a number of graphene-based materials in comparative adsorption and antimicrobial experiments where contaminant removal efficiency, maximum adsorption capacity, and bacterial reduction are probed. This preliminary investigation informs on the practicality of using graphene-based materials as filtration media and provides a discussion on the scaling-up and optimization of this prospective filtration technology for spacecraft potable water systems.

graphene↗
NASA NTRSDate not supplied

Graphene-Based Filtration Media for Spacecraft Potable Water Systems: An Early Investigation

Graphene-based materials have allowed fundamental advances in fields such as energy storage, electronics development, material science, optics, medicine, and water processing due to their unique two-dimensional structure, mechanical robustness, large surface, and high conductivity. However, little to no effort has been devoted to exploiting and studying these materials to develop new water technologies suited for spacecraft applications. One such application is the potential use of graphene-based materials as filtration media for reclaimed water. Therefore, studying the adsorptive performance of these new materials becomes crucial in identifying the opportunity to replace/upgrade state-of-the-art filtration media currently used in space vehicles with water recovery capability; especially if consumable requirements can be lessened as a result of extended filtration capacity. This early Life-Support-Systems investigation pioneers in graphene research by testing a number of graphene-based materials in comparative adsorption and antimicrobial experiments where contaminant removal efficiency, maximum adsorption capacity, and bacterial reduction are probed. This preliminary investigation informs on the practicality of using graphene-based materials as filtration media and provides a discussion on the scaling-up and optimization of this prospective filtration technology for spacecraft potable water systems.

graphene↗
NASA NTRS1974

Potable water taste enhancement

An analysis was conducted to determine the causes of and remedies for the unpalatability of potable water in manned spacecraft. Criteria and specifications for palatable water were established and a quantitative laboratory analysis technique was developed for determinig the amounts of volatile organics in good tasting water. Prototype spacecraft water reclamation systems are evaluated in terms of the essential palatability factors.

Source record↗
NASA NTRS2010

Crew Exploration Vehicle Potable Water System Verification Description

A stored water system on the crew exploration vehicle (CEV) will supply the crew with potable water for: drinking and food rehydration, hygiene, medical needs, sublimation, and various contingency situations. The current baseline biocide for the stored water system is ionic silver, similar in composition to the biocide used to maintain the quality of the water, transferred from the orbiter to the International Space Station, stored in contingency water containers. In the CEV water system, a depletion of the ionic silver biocide is expected due to ionic silver-plating onto the surfaces of materials within the CEV water system, thus negating its effectiveness as a biocide. Because this may be the first time NASA is considering a stored water system for long-term missions that do not maintain a residual biocide, a team of experts in materials compatibility, biofilms and point-of-use filters, surface treatment and coatings, and biocides has been created to pinpoint concerns and perform the testing that will help alleviate concerns related to the CEV water system.

Tuan, George↗
NASA NTRSDate not supplied

The potable water system in Skylab

Description of the medical requirements, development, system operation, and in-flight performance of the Skylab potable water system. Emphasized is the description of the unique features involving new space-flight concepts, procedures, and design incorporated in Skylab. The water supplied to the three Skylab missions was preloaded in stainless-steel tanks. These tanks were fitted with positive expulsion stainless-steel bellows. In-flight iodination of the water, for bacterial control, was accomplished as required. An in-flight bactericide monitor was used periodically to determine the level of bactericide in the water. Prior to the delivery of the water to the crewmen for consumption, the water was passed through a cation exchange resin for metallic ion removal and then heated for food reconstitution or chilled for drinking.

R. L. Sauer↗
NASA NTRS1972

Development of a method for the determination of iodine in spacecraft potable water

A one-reagent indicator solution has been prepared for the analysis of iodine concentrations in the range of 0.5 to 12 mg/1 of I2 for use on the potable water proposed for the Skylab project. The indicator solution was formulated to contain the minimum concentrations of reagents for optimum analytical performance. Performance tests indicated that the reagent is stable for at least six months and is reliable for the determination of I2 under a variety of conditions of I(-) concentrations and sample temperatures. Visual estimations as low as 0.5 mg/1 were obtained without difficulty and the stability of the developed color allows visual determinations from 0.5 to 12 mg/1 of I2 with a relatively small error.

Whittle, G. P.↗
NASA NTRS2007

Overview of Potable Water Systems on Spacecraft Vehicles and Applications for the Crew Exploration Vehicle (CEV)

Providing water necessary to maintain life support has been accomplished in spacecraft vehicles for over forty years. This paper will investigate how previous U.S. space vehicles provided potable water. The water source for the spacecraft, biocide used to preserve the water on-orbit, water stowage methodology, materials, pumping mechanisms, on-orbit water requirements, and water temperature requirements will be discussed. Where available, the hardware used to provide the water and the general function of that hardware will also be detailed. The Crew Exploration Vehicle (CEV or Orion) water systems will be generically discussed to provide a glimpse of how similar they are to water systems in previous vehicles. Conclusions on strategies that could be used for CEV based on previous spacecraft water systems will be made in the form of questions and recommendations.

Peterson, Laurie J.↗
NASA NTRSDate not supplied

Double ChemFET for the In-Line Monitoring of Silver Dosing in Potable Water Systems

With NASA Advanced Exploration Systems (AES) Life Support Systems (LSS)baselining ionic silver (Ag+) as the biocide of choice, development in silver monitoring technologies becomes necessary to monitor and control Ag+ release. Ion-selective field effect transistors (ISFETs) and chemically-sensitive field effect transistors (ChemFETs) are capable of selective detection of Ag+ with reversible and low detection limit responses. However, one major hurdle to ChemFET technologies is the requirement of a reference electrode, which can leak its fill solution into the potable water system and is prone to drift requiring frequent calibration. To circumvent this issue, a double chemically-sensitive field effect transistor (dChemFET) is proposed. The dChemFET uses a second ChemFET to selectively monitor the counter ion and serves in place of the reference electrode. This work reports on the development of the dChemFET, starting with the development of the Ag+ andNO3- ion selective membranes (ISMs) to be used in the ChemFETs. The Ag+ ISM was tested in 50-105 ppb Ag+ and showed linear, sub-Nernstian response. The NO3- ISM was tested in50-500 ppb silver ion equivalents of nitrate ion (Ag+ equiv. of NO3-) and shows linear, sub-Nernstian response as well . However, the Ag+ and NO3- ISMs face significant challenges in terms of drift that obstruct its application for long-term monitoring, but it can serve as a starting point for demonstrating the dChemFET proof of concept.

John Abdou↗
NASA NTRS2012

Antimicrobial Resources for Disinfection of Potable Water Systems for Future Spacecraft

As human exploration adventures beyond low earth orbit, life support systems will require more innovation and research to become self-sustaining and durable. One major concern about future space travel is the ability to store and decontaminate water for consumption and hygiene. This project explores materials and technologies for possible use in future water systems without requiring point-of-use (POU) filtering or chemical additives such as iodine or silver that require multiple doses to remain effective. This experimentation tested the efficacy of a variety of antimicrobial materials against biofilm formation in a high shear CDC Biofilm Reactor (CBR) and some materials in a low shear Drip Flow Reactor (DFR) which(also utilizes ultra violet light emitting diodes (UVLEDs) as an antimicrobial resource. Most materials were tested in the CBR using the ASTM E 2562-07 1method involving the Pseudomonas aeruginosa and coupon samples that vary in their antimicrobial coatings and surface layer topographies. In a controlled environmental chamber (CEC), the CBR underwent a batch phase, continuous flow phase (CFP), and a harvest before analysis. The DFR portion of this experimentation was performed in order to assess the antimicrobial capabilities of ultraviolet-A LEDs (UV-A) in potable water systems. The ASTM E 2647-08 was modified in order to incorporate UV-A LEDs and to operate as a closed, re-circulating system. The modified DFR apparatus that was utilized contains 4 separate channels each of which contain 2 UV-A LEDs (1 chamber is masked off to serve as a control) and each channel is equipped with its own reservoir and peristaltic pump head. The 10 DFR runs discussed in this report include 4 initial experimental runs that contained blank microscope slides to test the UVA LEDs alone, 2 that incorporated solid silver coupons, 2 that utilized titanium dioxide (Ti02) coupons as a photocatalyst, and 2 runs that utilized silver coated acrylic slides. Both the CBR and DFR experiments were analyzed for microbial content via heterotrophic plate counts (HPC) and acridine orange direct counts (AODC). Ofthe materials used in the CBR, only two materials performed as anti~icrobials under high shear conditions (a reduction of 5 or more logs) showing a>7 log reduction in viable microbes.

Morford, Megan A.↗
NASA NTRS1972

Electrochemical approach for passivating steel and other metals and for the simultaneous production of a biocide to render water potable

Potentiostatic polarization curves indicated that the cathodic reactions in deaerated KI-I2 water solutions were due to iodine reduction and hydrogen evolution. In the presence of oxygen an additional reduction wave appeared. Anodic polarization curves revealed that iodine could be produced in the region of potential from +600 to +1000 nv vs. SCE.

Source record↗