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At least 235 records · Page 13

All sources NASA NTRS DOE OSTI

NASA NTRS2009

Environmental Control and Life Support Integration Strategy for 6-Crew Operations Stephanie Duchesne

The International Space Station (ISS) crew compliment has increased in size from 3 to 6 crew members . In order to support this increase in crew on ISS, the United States on-orbit Segment (USOS) has been outfitted with a suite of regenerative Environmental Control and Life Support (ECLS) hardware including an Oxygen Generation System(OGS), Waste and Hygiene Compartment (WHC), and a Water Recovery System (WRS). The WRS includes the Urine Processor Assembly (UPA) and the Water Processor Assembly (WPA). With this additional life support hardware, the ISS has achieved full redundancy in its on-orbit life support system between the USOS and Russian Segment (RS). The additional redundancy created by the Regenerative ECLS hardware creates the opportunity for independent support capabilities between segments, and for the first time since the start of ISS, the necessity to revise Life Support strategy agreements. Independent operating strategies coupled with the loss of the Space Shuttle supply and return capabilities in 2010 offer new and unique challenges. This paper will discuss the evolution of the ISS Life Support hardware strategy in support of 6-Crew on ISS, as well as the continued work that is necessary to ensure the support of crew and ISS Program objectives through the life of station.

Duchesne, Stephanie M.↗

NASA NTRS2010

Environmental Control and Life Support Integration Strategy for 6-Crew Operations

The International Space Station (ISS) crew complement has increased in size from 3 to 6 crew members. In order to support this increase in crew on ISS, the United States on-orbit Segment (USOS) has been outfitted with a suite of regenerative Environmental Control and Life Support (ECLS) hardware including an Oxygen Generation System (OGS), Waste and Hygiene Compartment (WHC), and a Water Recovery System (WRS). The WRS includes the Urine Processor Assembly (UPA) and the Water Processor Assembly (WPA). With this additional life support hardware, the ISS has achieved full redundancy in its on-orbit life support system between the t OS and Russian Segment (RS). The additional redundancy created by the Regenerative ECLS hardware creates the opportunity for independent support capabilities between segments, and for the first time since the start of ISS, the necessity to revise Life Support strategy agreements. Independent operating strategies coupled with the loss of the Space Shuttle supply and return capabilities in 2010 offer new and unique challenges. This paper will discuss the evolution of the ISS Life Support hardware strategy in support of 6-Crew on ISS, as well as the continued work that is necessary to ensure the support of crew and ISS Program objectives through the life of station

Duchesne, Stephanie M.↗

NASA NTRS2013

Functional Performance of an Enabling Atmosphere Revitalization Subsystem Architecture for Deep Space Exploration Missions

A subsystem architecture derived from the International Space Station's (ISS) Atmosphere Revitalization Subsystem (ARS) has been functionally demonstrated. This ISS-derived architecture features re-arranged unit operations for trace contaminant control and carbon dioxide removal functions, a methane purification component as a precursor to enhance resource recovery over ISS capability, operational modifications to a water electrolysis-based oxygen generation assembly, and an alternative major atmospheric constituent monitoring concept. Results from this functional demonstration are summarized and compared to the performance observed during ground-based testing conducted on an ISS-like subsystem architecture. Considerations for further subsystem architecture and process technology development are discussed.

Perry, Jay L.↗

NASA NTRS2015

Continued Development of Compact Multi-Gas Monitor for Life Support Systems Control in Space

Miniature optic gas sensors (MOGS) based on luminescent materials have shown great potential as alternatives to NIR-based gas sensor systems for the Portable Life Support System (PLSS). The unique capability of MOGS for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of MOGS humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages of MOGS over both traditional and advanced Non-Dispersive Infrared (NDIR) gas sensors, which have shown so far longer life than luminescent sensors. In this paper we present the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted at Intelligent Optical Systems laboratories, a United Technology Corporation Aerospace Systems (UTAS) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems and the advantages and limitations found through detailed sensor validation are discussed.

Delgado, Jesus↗

NASA NTRS2016

Continued Development of Compact Multi-gas Monitor for Life Support Systems Control in Space

Miniature optic gas sensors (MOGS) based on luminescent materials have shown great potential as alternatives to Near-Infrared-based gas sensor systems for the advanced space suit portable life support system (PLSS). The unique capability of MOGS for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of MOGS humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages of MOGS over both traditional and advanced Non-Dispersive Infrared (NDIR) gas sensors, which have shown so far longer life than luminescent sensors. This paper presents the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted at Intelligent Optical Systems laboratories, a United Technology Corporation Aerospace Systems (UTAS) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems and the advantages and limitations found through detailed sensor validation are discussed.

Delgado-Alonso, Jesús↗

NASA NTRS2016

Continued Development of Compact Multi-Gas Monitor for Life Support Systems Control in Space

Miniature optical gas sensors based on luminescent materials have shown great potential as alternatives to NIR-based gas sensor systems for the Portable Life Support System (PLSS). The unique capability of luminescent sensors for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages over both traditional and advanced non-dispersive infrared (NDIR) gas sensors, which have so far shown longer life than luminescent sensors. In this paper we present the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted in Intelligent Optical Systems laboratories, a United Technologies Corporation Aerospace Systems (UTC) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems, and the advantages and limitations found through detailed sensor validation are discussed.

Delgado-Alonso, Jesus↗

NASA NTRS2013

Investigation of DMSD Trend in the ISS Water Processor Assembly

The ISS Water Recovery System (WRS) is responsible for providing potable water to the crew, to the Oxygen Generation System (OGS) for oxygen production via electrolysis, to the Waste & Hygiene Compartment (WHC) for flush water, and for experiments on ISS. The WRS includes the Water Processor Assembly (WPA) and the Urine Processor Assembly (UPA). The WPA processes condensate from the cabin air and distillate produced by the UPA. In 2010, an increasing trend in the Total Organic Carbon (TOC) in the potable water was ultimately identified as dimethylsilanediol (DMSD). The increasing trend was ultimately reversed after replacing the WPA's two multifiltration beds. However, the reason for the TOC trend and the subsequent recovery was not understood. A subsequent trend occurred in 2012. This paper summarizes the current understanding of the fate of DMSD in the WPA, how the increasing TOC trend occurred, and the plan for modifying the WPA to prevent recurrence.

Carter, Layne↗

DOE OSTI2023

Degradation and recovery of solid oxide fuel cell performance by control of cathode surface acidity: Case study – Impact of Cr followed by Ca infiltration

Solid oxide fuel cells (SOFC) have attracted attention as clean and efficient energy conversion devices with low emissions. However, several degradation mechanisms limit the electrochemical performance of current SOFCs, with cathode degradation due to Cr-poisoning from metal interconnects particularly problematic. The acidity/basicity of binary additives has been found to be a sensitive descriptor of the oxygen exchange kinetics, indicating that acidic Cr-species/basic Ca-species can be expected to deactivate/activate the cathode surface, respectively. Inspired by recent advances, the feasibility of relative acidity as a tool for reviving degraded SOFCs is demonstrated by neutralizing Cr-poisoned SOFCs by subsequent serial infiltration of Ca-species. Furthermore, a model mixed ionic and electronic conducting oxide, Pr 0.1 Ce 0.9 O 2-δ (PCO), is selected as the cathode material. Area-specific resistances (ASR) of symmetric cells obtained by electrochemical impedance spectroscopy show that Cr-infiltration results in a seven-fold increase in ASR, while subsequent infiltration of Ca-species leads to complete recovery. Performance degradation and recovery are attributed to depressed/enhanced redox properties at the PCO surface, as supported by XPS analysis. Experiments using anode-supported fuel cells show a reduction in peak power density by 26% upon Cr-infiltration, reversed following Ca-infiltration, after which no degradation is observed during subsequent operation for 100 h.

(Pr,Ce)O2-δ↗

NASA NTRS2010

Microwave Plasma Hydrogen Recovery System

A microwave plasma reactor was developed for the recovery of hydrogen contained within waste methane produced by Carbon Dioxide Reduction Assembly (CRA), which reclaims oxygen from CO2. Since half of the H2 reductant used by the CRA is lost as CH4, the ability to reclaim this valuable resource will simplify supply logistics for longterm manned missions. Microwave plasmas provide an extreme thermal environment within a very small and precisely controlled region of space, resulting in very high energy densities at low overall power, and thus can drive high-temperature reactions using equipment that is smaller, lighter, and less power-consuming than traditional fixed-bed and fluidized-bed catalytic reactors. The high energy density provides an economical means to conduct endothermic reactions that become thermodynamically favorable only at very high temperatures. Microwave plasma methods were developed for the effective recovery of H2 using two primary reaction schemes: (1) methane pyrolysis to H2 and solid-phase carbon, and (2) methane oligomerization to H2 and acetylene. While the carbon problem is substantially reduced using plasma methods, it is not completely eliminated. For this reason, advanced methods were developed to promote CH4 oligomerization, which recovers a maximum of 75 percent of the H2 content of methane in a single reactor pass, and virtually eliminates the carbon problem. These methods were embodied in a prototype H2 recovery system capable of sustained high-efficiency operation. NASA can incorporate the innovation into flight hardware systems for deployment in support of future long-duration exploration objectives such as a Space Station retrofit, Lunar outpost, Mars transit, or Mars base. The primary application will be for the recovery of hydrogen lost in the Sabatier process for CO2 reduction to produce water in Exploration Life Support systems. Secondarily, this process may also be used in conjunction with a Sabatier reactor employed to stockpile life-support oxygen as well as propellant and fuel production from Martian atmospheric CO2

Atwater, James↗

DOE OSTI2024

Photocatalytic water splitting for large-scale solar-to-chemical energy conversion and storage

Sunlight-driven water splitting allows renewable hydrogen to be produced from abundant and environmentally benign water. Large-scale societal implementation of this green fuel production technology within energy generation systems is essential for the establishment of sustainable future societies. Among various technologies, photocatalytic water splitting using particulate semiconductors has attracted increasing attention as a method to produce large amounts of green fuels at low cost. The key to making this technology practical is the development of photocatalysts capable of splitting water with high solar-to-fuel energy conversion efficiency. Furthermore, advances that enable the deployment of water-splitting photocatalysts over large areas are necessary, as is the ability to recover hydrogen safely and efficiently from the produced oxyhydrogen gas. This lead article describes the key discoveries and recent research trends in photosynthesis using particulate semiconductors and photocatalyst sheets for overall water splitting, via one-step excitation and two-step excitation (Z-scheme reactions), as well as for direct conversion of carbon dioxide into renewable fuels using water as an electron donor. We describe the latest advances in solar water-splitting and carbon dioxide reduction systems and pathways to improve their future performance, together with challenges and solutions in their practical application and scalability, including the fixation of particulate photocatalysts, hydrogen recovery, safety design of reactor systems, and approaches to separately generate hydrogen and oxygen from water.

30 DIRECT ENERGY CONVERSION↗

NASA NTRS2002

Oxygen Penalty for Waste Oxidation in an Advanced Life Support System: A Systems Approach

Oxidation is one of a number of technologies that are being considered for waste management and resource recovery from waste materials generated on board space missions. Oxidation processes are a very effective and efficient means of clean and complete conversion of waste materials to sterile products. However, because oxidation uses oxygen there is an "oxygen penalty" associated either with resupply of oxygen or with recycling oxygen from some other source. This paper is a systems approach to the issue of oxygen penalty in life support systems and presents findings on the oxygen penalty associated with an integrated oxidation-Sabatier-Oxygen Generation System (OGS) for waste management in an Advanced Life Support System. The findings reveal that such an integrated system can be operated to form a variety of useful products without a significant oxygen penalty.

Pisharody, Suresh↗

NASA NTRS2010

Impact of Water Recovery from Wastes on the Lunar Surface Mission Water Balance

Future extended lunar surface missions will require extensive recovery of resources to reduce mission costs and enable self-sufficiency. Water is of particular importance due to its potential use for human consumption and hygiene, general cleaning, clothes washing, radiation shielding, cooling for extravehicular activity suits, and oxygen and hydrogen production. Various water sources are inherently present or are generated in lunar surface missions, and subject to recovery. They include: initial water stores, water contained in food, human and other solid wastes, wastewaters and associated brines, ISRU water, and scavenging from residual propellant in landers. This paper presents the results of an analysis of the contribution of water recovery from life support wastes on the overall water balance for lunar surface missions. Water in human wastes, metabolic activity and survival needs are well characterized and dependable figures are available. A detailed life support waste model was developed that summarizes the composition of life support wastes and their water content. Waste processing technologies were reviewed for their potential to recover that water. The recoverable water in waste is a significant contribution to the overall water balance. The value of this contribution is discussed in the context of the other major sources and loses of water. Combined with other analyses these results provide guidance for research and technology development and down-selection.

Fisher, John W.↗

NASA NTRS1987

Hyperbaric hyperoxia reversibly inhibits erythrocyte phospholipid fatty acid turnover

The effect of hyperbaric hyperoxia on the acylation of membrane phospholipid was studied by measuring the rates of activation of exogenous tritiated oleic acid to acyl thioester and of transesterification of the thioester into membrane phospholipids in intact human erythrocytes obtained 1 h after an exposure of the subjects to a hyperbaric oxygen atmosphere (3.5 h, 100 pct O2, 3 ATA). Exposure to pure oxygen was found to inhibit both the acylation and transesterification reactions by more than 30 percent, with partial recovery detected 24 h later. On the other hand, no rate changes were observed when isolated membranes from the same batches of cells were used in similar experiments. It is suggested that the decrease in the incorporation of tritiated oleic acid after hyperbaric hyperoxia may reflect an early event in the pathogenesis of oxygen-induced cellular injury and that it may be a useful index for the assessment of the tolerance of tissues to hyperoxia.

Dise, Craig A.↗

NASA NTRS1994

Results from LDEF experiment A0114: The interaction of atomic oxygen with materials surfaces at orbital altitudes

In 1975 the University of Alabama in Huntsville proposed an experiment for the Long Duration Exposure Facility (LDEF) designed to investigate the effects of the collision of the ambient orbital atmosphere, mainly consisting of atomic oxygen, with satellite surfaces travelling at about 8 km per second. In 1989, the potential for recovery of significant data from A0114 on a wide variety of materials was recognized and funding for three years of data analysis was appropriated. Some significant or unique findings from the experiment A0114 include: numerous measurements of oxidation rates of surfaces under fast O atom bombardment, including Si, Ge, GaAs, SiC, and optical quality metal films; measurement of the stable attitude of the LDEF spacecraft in orbit using the gas dynamics pinhole camera; description of the formation of thick oxide films on copper at 20 C with fast oxygen; measurement of erosion rates of Kapton and other polymers at space station lifetime atomic oxygen fluences (10(exp 22) atoms/sq cm); and measurement of the cosmogenic isotopes Be-7 on spacecraft surfaces.

Gregory, John C.↗

NASA NTRS2024

Reliable and Efficient Electrochemical Recovery of O 2 from Metabolic CO 2 at the International Space Station (ISS)

Maximum O 2 recovery from metabolic carbon dioxide (CO 2 ) is desired for future long-duration missions beyond Low Earth Orbit (LEO). The O 2 recovery for the Environmental Control and Life Support System (ECLSS) at the International Space Station (ISS), presently limited to 50% (Sabatier), must be highly reliable and efficient and recover a minimum of 75% oxygen (O 2 ) from metabolic CO 2 . An alternative technology development effort currently underway at NASA Marshall Space Flight Center (MSFC) via a Microfluidic Electrochemical Reactor (MFECR) approach has the potential to increase O 2 recovery significantly and reduce the complexity of the ECLSS O 2 recovery at the ISS as it would replace three pieces, the CO 2 Reduction Assembly (CRA) (Sabatier reactor), the Oxygen Generation Assembly (OGA), and the Plasma Pyrolysis Assembly (PPA). The MFECR's electrochemical process generates ethylene (C 2 H 4 ) and carbon moxide (CO) instead of methane (CH 4 ) (Sabatier) as a byproduct, eliminating the need for further dehydrogenation through the PPA. As in the OGA, the MFECR's electrochemical process generates O 2 and hydrogen (H 2 ) from the water electrolysis process. MSFC and the University of Texas in Arlington (UTA) have jointly designed and fabricated an MFECR's single cell that operates at ambient conditions and utilizes a proprietary catalysis highly selective on reducing CO 2 to C 2 H 4 and CO at the cathode. This MFECR's single cell consists of gas diffusion layers at the cathode and anode for respective intake of CO 2 and output of O 2 from the catalytic layer. This approach is expected to substantially improve the ISS ECLSS sustainability and reduce power and weight requirements as the MFECR would replace three units currently installed in the ISS. In this paper, the authors discuss the outcome of preliminary tests, the current development, and the evaluation efforts on different alternatives for the cathode and the anode configurations, the setup of the MFECR at an engineering development unit (EDU) scale, and the O 2 recovery performance, and evaluation efforts on different alternatives on not only the configuration and setup of the MFECR at an Engineering Design Unit (EDU) scale but also the selection of component materials.

Jesus A Dominguez↗

DOE OSTI2023

Interface-independent sound speed and thermal conductivity of atomic-layer-deposition-grown amorphous AlN / Al 2 O 3 multilayers with varying oxygen composition

Dielectric amorphous multilayers (AMLs) play a critical role in a wide array of technologies such as optical coatings, nanoelectronics, energy harvesting, and recovery devices. However, despite their wide applications, a robust understanding of the effect of the interplay between chemical and structural disorder on the thermal properties of AMLs is still lacking. Therefore, in this paper, we experimentally and numerically investigate the effects of composition and interface density on the sound speed and thermal conductivity of a series of amorphous aluminum nitride and aluminum oxide multilayers grown via plasma-enhanced atomic layer deposition. To systematically change the composition, the oxygen content of the AMLs is proportionally varied with interface density during growth. We find that the longitudinal sound speed of these AMLs is dictated by the oxygen content instead of the number of interfaces. The thermal conductivity, in contrast, is dictated by both interface density and oxygen content. The interfaces act to decrease the thermal conductivity, whereas the oxygen content increases the thermal conductivity. Due to the competing influence of the interfaces and oxygen content, the thermal conductivity of the AMLs remains nearly constant as a function of interface density. Furthermore, our study provides crucial insights into the effect of the interplay of composition and interfaces on the sound speed and thermal conductivity of AMLs.

36 MATERIALS SCIENCE↗

NASA NTRSDate not supplied

Status of ISS Water Management and Recovery

Water management on ISS is responsible for the provision of water to the crew for drinking water, food preparation, and hygiene, to the Oxygen Generation System (OGS) for oxygen production via electrolysis, to the Waste & Hygiene Compartment (WHC) for flush water, and for experiments on ISS. This paper summarizes water management activities on the ISS US Segment as of March 2022 and provides a status of the performance and issues related to the operation of the Water Processor Assembly (WPA) and Urine Processor Assembly (UPA).

Water Recovery System↗

NASA NTRSDate not supplied

Status of ISS Water Management and Recovery

Water Recovery↗