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DOE OSTI2022

Oxygen-Plasma-Induced Hetero-Interface NiFe2O4/NiMoO4 Catalyst for Enhanced Electrochemical Oxygen Evolution

The electrolysis of water to produce hydrogen is an effective method for solving the rapid consumption of fossil fuel resources and the problem of global warming. The key to its success is to design an oxygen evolution reaction (OER) electrocatalyst with efficient conversion and reliable stability. Interface engineering is one of the most effective approaches for adjusting local electronic configurations. Adding other metal elements is also an effective way to enrich active sites and improve catalytic activity. Herein, high-valence iron in a heterogeneous interface of NiFe 2 O 4 /NiMoO 4 composite was obtained through oxygen plasma to achieve excellent electrocatalytic activity and stability. In particular, 270 mV of overpotential is required to reach a current density of 50 mA cm -2 , and the overpotential required to reach 500 mA cm -2 is only 309 mV. The electron transfer effect for high-valence iron was determined by X-ray photoelectron spectroscopy (XPS). The fast and irreversible reconstruction and the true active species in the catalytic process were identified by in situ Raman, ex situ XPS, and ex situ transmission electron microscopy (TEM) measurements. This work provides a feasible design guideline to modify electronic structures, promote a metal to an active oxidation state, and thus develop an electrocatalyst with enhanced OER performance.

36 MATERIALS SCIENCE↗

NASA NTRSDate not supplied

Unbounded Learning Environments as an Approach to Preserving Design Flexibility Demonstrated With Nasa Stem Enhancement in Earth Science (SEES) Students

The Artemis Lunar program is providing opportunity for young scientists and engineers to contribute towards leading edge design concepts regarding early on-surface work areas that are aligned with major national initiatives. Therefore, it is imperative in any discovery process that those young scientists and engineers be provided the bandwidth or operating in a ‘greenfield’ technology environment that encourages new ideas, and perhaps the discovery of ideas that would not be realized within typical structured engineering constraints. To facilitate this concept, the use of unbounded teaching methods was utilized to provide a low-constraint environment from which students can design and discover the requirements that are bounded by the natural environment of the lunar surface, and then build up design requirements un-hindered by budgetary and/or logistics realizations of the moment funding capabilities. Specifically, this design exercise provided the students to operate with unlimited budgets, and unlimited up-mass lifts to the lunar surface to develop a preliminary feasible process for establishing a working lunar research based upon the near-area permanently shadowed regions within the lunar surface. In concept, working near PSRs will be advantageous as they receive near eternal shielding from solar radiation and may potentially host numerous volatile substances such as water ice, methane, hydrogen sulfide and helium-3 that will be the target of scientific investigation and in-situ resource utilization ISRU. The advantage of an upstream working area is that the quality of return materials could potentially be exponential when including an upstream analysis prior to earth-return missions. Furthermore, it’s well known within the scientific and engineering community that working with the base materials in front of human eyes elucidates new features and observations that may not survive when stored and shipped to Earth. Finally, it is theorized that these methods and techniques developing on the lunar surface would be applicable to other planets or cometary surfaces.

Education↗

DOE OSTI2023

Heat Pump Water Heater Guide for Small Businesses

This guide is intended for building owners and facility managers interested in electrifying commercial building water heating systems via new building systems or system retrofits. This guide is also a resource for contractors becoming familiar with commercial heat pump water heaters (HPWHs). This guide focuses on integrated air-source HPWH equipment, and background information, best practices, and key considerations are included here. A building owner or facility manager should review project considerations with an engineer or contractor.

decarbonization↗

NASA NTRS2006

Working Group Reports and Presentations: Asteroids

The study and utilization of asteroids will be an economical way to enable exploration of the solar system and extend human presence in space. There are thousands of near-earth objects (NEOs) that we will be able to reach. They offer resources, transportation, and exploration platforms, but also present a potential threat to civilization. Asteroids play a catastrophic role in the history of the Earth. Geological records indicate a regular history of massive impacts, which astronomical observations confirm is likely to continue with potentially devastating consequences. However, study and exploration of near earth asteroids can significantly increase advanced warning of an Earth impact, and potentially lead to the technology necessary to avert such a collision. Efforts to detect and prevent cataclysmic events would tend to foster and likely require international cooperation toward a unified goal of self-preservation. Exploration of asteroids will help us to understand our history and perhaps save our future. Besides the obvious and compelling scientific and security drivers for asteroid research and exploration, there are numerous engineering and industrial applications for near-term asteroid exploration. We have strong evidence that some asteroids are metal rich. Some are water and organic rich. They can be reached with a very low fuel cost compared to other solar system destinations. Once we reach them, there are efficient, simple extraction technologies available that would facilitate utilization. In addition, the costs of returning extracted resources from asteroids will be a fraction of the cost to return similar resources from the moon to Low Earth Orbit (LEO). These raw materials, extracted and shipped at relatively low cost, can be used to manufacture structures, fuel, and products which could be used to foster mankind s further exploration of the solar system. Asteroids also have the potential to offer transport to several destinations in the solar system. In addition to Mars and the Asteroid belt, it is possible to nudge the orbits of NEOs to provide convenient transport to other destinations. Resources to support life on these long voyages may be gathered from the host asteroid itself. As asteroids travel over a wide range of inclinations and ranges, they offer possible platforms to perform scientific investigations. These include unique vantage point observations of the sun and planets. These observations can help us to understand solar activity and space weather. They also afford us an opportunity to see how the earth looks from afar with different perspectives. When we look for planets outside of our solar system, these observations will help us to calibrate our data. Asteroids may also be used as platforms to support very long baseline interferometry with unprecedented angular resolutions.

Lewis, John↗

DOE OSTI2025

Primer to SWIFt 2.0 Technical Information Sheets

More than 16,000 publicly owned municipal wastewater treatment plants (WWTPs) in the U.S. treat a wide range of wastewater (WW) flows ranging from <0.5 to >200 MGD. Municipal WWTPs act as the last barrier before exposure to water-borne diseases and contaminants, thus serving as a critical infrastructure protecting human health and the environment. A recent survey by the American Society of Civil Engineers assigned the U.S.’s WW infrastructure a grade of D+ because of the number of improvements needed for end-of-life infrastructure with operating conditions being over or under design capacities. With increasing population growth and urbanization, the municipal WW sector needs to grow resiliently and sustainably to accommodate increasing sewer flows in the wake of new infrastructure needs and global priorities. In addition, this growth will be affected by rising concerns over constrained resources (e.g., electricity, energy, and water) and regulations. This necessitates molding the WW sector toward sustainability- and resiliency-related planning and innovations to address current and future needs while simultaneously producing profitable by-products.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

NASA NTRSDate not supplied

Case Study for Lunar ISRU Systems Utilizing Polar Water

In-Situ Resource Utilization (ISRU) is key to long term presence at any extraterrestrial destination. Current NASA direction is to achieve a sustainable presence on the lunar surface by 2028. Mission plans currently target the lunar South Pole to leverage the extended periods of solar illumination and allows for potential access to water ice in the permanently shadowed areas around the poles. With water, it is possible to produce both fuel and oxidizer to fully refuel a vehicle. In order to address ISRU infusion into mission planning, a study of an end-to-end ISRU propellant production system was initiated to assess ISRU architectures and obtain mass and power estimates for each. The results of these case studies will be presented. For this study, The ISRU system architecture involved two sites; the mine site in a shadowed crater where water ice is excavated and extracted from the regolith and the propellant production site at an illuminated ridge where the water is processed into liquefied O2 and H2 propellants. Fixed hardware would be emplaced at each site, with two alternating water tankers to transport water between them. Notional lunar sites were identified for this architecture for baseline environmental parameters. Technology solutions for each subsystem were selected based on those with the highest fidelity models or those that have empirical laboratory data to anchor to. While power needs were identified for each location, a power solution was not prescribed, therefore the masses presented do not include surface power systems. The baseline case in this study assumed that 10 mT of oxygen, along with enough hydrogen to support a propulsion mixture ratio of 6, must be produced in 225 days. Therefore 15 mT of water would need to be collected and processed. The baseline solution resulted in a system mass of5 mT and a total required power of 68kW. The majority of the mass was split between the ridge site system and the two water tankers (2.6 mTand 1.8mTrespectively). The majority of the required power was with three subsystems at approximately 20 kW each: hydrogen liquefaction, electrolysis, and the water extractor subsystem. Trades for four key variables are also presented, namely production rate, water concentration, dry overburden depth, and number of water transport trips. This can be compared to a system that targets oxygen from the minerals in the surface regolith material. A carbothermal reduction reactor system was used for this comparison. The use of direct solar thermal energy to process the regolith and the ease of access of the resource resulted in significantly lower values for the oxygen case: approximately 2.7 mT and 11.8 kW. However, the mass trade would favor the water case over successive missions where the hydrogen up-mass of 2 mT per mission will accrue against the oxygen system.1Aerospace Research Engineer, Chemical and Thermal Propulsion Systems Branch, Senior Member.2Mechanical Engineer, Propulsion and Power Division/Energy Conversion Systems, 2101 Nasa Pkwy/Mailcode EP3 Houston, TX 77058, AIAA member.

Lunar↗

DOE OSTI2020

A mass-transfer particle-tracking method for simulating transport with discontinuous diffusion coefficients

The problem of a spatially discontinuous diffusion coefficient (D(x)) is one that may be encountered in hydrogeologic systems due to natural geological features or as a consequence of numerical discretization of flow properties. To date, mass-transfer particle-tracking (MTPT) methods, a family of Lagrangian methods in which diffusion is jointly simulated by random walk and diffusive mass transfers, have been unable to solve this problem. This manuscript presents a new mass-transfer (MT) algorithm that enables MTPT methods to accurately solve the problem of discontinuous D(x). To achieve this, we derive a semi-analytical solution to the discontinuous D(x) problem by employing a predictor-corrector approach, and we use this semi-analytical solution as the weighting function in a reformulated MT algorithm. Furthermore, this semi-analytical solution is generalized for cases with multiple 1D interfaces as well as for 2D cases, including a 2 × 2 tiling of 4 subdomains that corresponds to a numerically-generated diffusion field. The solutions generated by this new mass-transfer algorithm closely agree with an analytical 1D solution or, in more complicated cases, trusted numerical results, demonstrating the success of our proposed approach.

42 ENGINEERING↗

NASA NTRS2010

Microbiological Tests Performed During the Design of the International Space Station Environmental Control and Life Support Systems. Part 1, Bulk Phase: Bulk Phase - Part 1

The design and manufacturing of the main Environmental Control and Life Support Systems (ECLSS) for the United States segments of the International Space Station (ISS) was an involved process that started in the mid 1980s, with the assessment and testing of competing technologies that could be used to clean the air and recycle water. It culminated in 2009 with the delivery and successful activation of the Water Recovery System (WRS) water processor (WP). The ECLSS required the work of a team of engineers and scientist working together to develop systems that could clean and/or recycle human metabolic loads to maintain a clean atmosphere and provide the crew clean water. One of the main goals of the ECLSS is to minimize the time spent by the crew worrying about vital resources not available in the vacuum of space, which allows them to spend most of their time learning to live in a microgravity environment many miles from the comforts of Earth and working on science experiments. Microorganisms are a significant part of the human body as well as part of the environment that we live in. Therefore, the ISS ECLSS design had to take into account the effect microorganisms have on the quality of stored water and wastewater, as well as that of the air systems. Hardware performance issues impacted by the accumulation of biofilm and/or microbiologically influenced corrosion were also studied during the ECLSS development stages. Many of the tests that were performed had to take into account the unique aspects of a microgravity environment as well as the challenge of understanding how to design systems that could not be sterilized or maintained in a sterile state. This paper will summarize the work of several studies that were performed to assess the impacts and/or to minimize the effects of microorganisms in open, semi-closed and closed loop life support system. The biofilm and biodeterioration studies that were performed during the design and test periods will be presented in a future publication.

Roman, Monsi C.↗

NASA NTRS2010

Overview of Microbiological Tests Performed During the Design of the International Space Station Environmental Control and Life Support Systems

The design and manufacturing of the main Environmental Control and Life Support Systems (ECLSS) for the United States segments of the International Space Station (ISS) was an involved process that started in the late 1980's, with the assessment and testing of competing technologies that could be used to clean the air and recycle water. It culminated in 2009 with the delivery and successful activation of the Water Recovery System (WRS) water processor (WP). The ECLSS required the work of a team of engineers and scientist working together to develop systems that could clean and/or recycle human metabolic loads to maintain a clean atmosphere and provide the crew clean water. One of the main goals of the ECLSS is to minimize the time spent by the crew worrying about vital resources not available in the vacuum of space, which allows them to spend most of their time learning to live in a microgravity environment many miles from the comforts of Earth and working on science experiments. Microorganisms are a significant part of the human body as well as part of the environment that we live in. Therefore, the ISS ECLSS design had to take into account the effect microorganisms have on the quality of stored water and wastewater, as well as that of the air systems. Hardware performance issues impacted by the accumulation of biofilm and/or microbiologically influenced corrosion were also studied during the ECLSS development stages. Many of the tests that were performed had to take into account the unique aspects of a microgravity environment as well as the challenge of understanding how to design systems that could not be sterilized or maintained in a sterile state. This paper will summarize the work of several studies that were performed to assess the impacts and/or to minimize the effects of microorganisms in the design of a closed loop life support system.

Roman, Monsi C.↗

DOE OSTI2025

Alaska Liquid Natural Gas Pipeline Front-End Engineering & Design (Final Technical Report)

The Alaska Gasline Development Corporation (AGDC) is Alaska’s natural gas infrastructure development corporation established in 2013. AGDC’s mission is to maximize the benefit of Alaska’s vast North Slope natural gas resources for Alaskans through the development of infrastructure necessary to move the gas into local and international markets. AGDC was identified for a Congressionally Directed Spending (CDS) project for funding in the Energy and Water Development and Related Agencies Appropriations Act, 2023 under the heading: “Congressionally Directed Energy Efficiency and Renewable Energy Projects.” The CDS included $\$$4,000,000 of direct funding, with required match funds, to move the project forward. Alaska’s North Slope holds America’s largest proven and conventional natural gas supply. The integrated Alaska LNG Project will deliver 3.5 billion cubic feet of natural gas per day from Alaska’s North Slope gas fields to Alaskans as well as to a marine terminal located at tidewater in Cook Inlet. Alaska LNG is an integrated gas infrastructure project with three major components: a gas treatment plant (GTP) located at Prudhoe Bay, an 807-mile (1,287 km) gas pipeline (Mainline Pipeline) to Southcentral Alaska with interconnections for in-state gas use, and a natural gas liquefaction facility (LNG Facility) in Nikiski, Alaska. The integrated Alaska LNG Project has several strategic advantages including proven gas resources, existing upstream infrastructure, an advantageous arctic climate for LNG production, proximity to LNG markets, a track record of reliability from a state that first began exporting LNG to Japan in 1969, and broad support from Alaskans. North Slope natural gas is a conventional resource and can be produced with minimal drilling at a fraction of the carbon dioxide emissions of shale gas from the Lower 48 states. Through the development of the Alaska LNG Project, Alaska can provide energy security to Alaskans and a stable source of LNG to the Asia-Pacific region for generations. The Alaska LNG Project has been progressed through Pre-Front-End Engineering Design (Pre-FEED) and has obtained all major federal and State of Alaska permits and authorizations to construct the project, including the Federal Energy Regulatory Commission (FERC) Order Granting Authorization Under Section 3 of the Natural Gas Act. On September 5, 2024, the U.S. Department of Energy (DOE), National Energy Technology Laboratory (NETL) awarded Project No. DE-FE0032307 to AGDC with the objective to progress the project to Front-End Engineering Design (FEED) entry for the Alaska LNG Project Phase 1 Pipeline. The award Start Date was made effective July 1, 2023, with a Period of Performance through June 30, 2025. On March 27, 2025, AGDC announced the execution of definitive commercial agreements with Glenfarne Alaska LNG, LLC, an affiliate of Glenfarne Group, LLC, (together as “Glenfarne”), to lead the development of the Alaska LNG Project and enter FEED for the Phase 1 Pipeline. Project activities are now funded and directed by this private sector partner who holds a 75% interest in 8 Star Alaska, LLC (8 Star). 8 Star holds the assets of the Alaska LNG Project. As planned, AGDC continues to hold 25% minority interest in 8 Star and will play a governance role moving forward with Alaska LNG. This definitive commercial agreement milestone led to the successful completion of AGDC’s Statement of Project Objectives (SOPO) for FEED entry and led to the completion of DOE Project No. DE-FE0032307. At conclusion of the SOPO, AGDC also reached the award’s maximum federal cost share of $\$$4,000,000. AGDC is, therefore, providing Final Technical Report to close out DOE Project No. DE-FE0032307.

02 PETROLEUM↗

DOE OSTI2020

Sustainability assessment of alternative jet fuel for the U.S. Department of Defense

The United States Department of Defense (DoD) is considering replacing the 2.8 billion gallons of petroleum jet fuel consumed within the continental United States (CONUS) annually with alternative jet fuels to reduce vulnerability to price and supply fluctuations and improve sustainability. We evaluate the feasibility of replacing DoD CONUS jet fuel with alternative jet fuel from domestic feedstocks and assess the cost, greenhouse gas (GHG) emissions, energy balance, land, water, and fertilizer impacts of nine alternative jet fuel pathways. The feedstocks include terrestrial crops (soy, corn, wood, and grass), marine microalgae, and by-products (forestry residue, municipal solid waste, and waste oil) converted by extraction, fermentation, or thermo-chemical conversion, paired with upgrading steps. We found that domestic biomass feedstocks can meet the DoD CONUS jet fuel demand without significantly affecting food supply. Alternative pathways cost more than petroleum jet fuel ($0.78 l -1 and emitting 89 g CO 2 equivalent (CO 2e ) MJ -1 ), but many lowered GHG emissions. The forestry residue and waste oil pathways yielded the lowest costs ($\$0.92$ and $\$0.82$ l -1 , respectively), decreased emissions (23 and 35 g CO 2 e MJ -1 , respectively), and had negligible effects on land, water, and fertilizer resources. Finally, tradeoffs among sustainability metrics are further explored with a sensitivity analysis and by evaluating carbon-cost scenarios.

09 BIOMASS FUELS↗

DOE OSTI2025

Genetically engineered poplar wood effectively enhances the efficiency of deep eutectic solvent-mediated one-pot processing

Although lignocellulosic biomass is a renewable resource with the potential to replace fossil-derived fuels and chemicals, its recalcitrance, largely due to lignin, limits its utilization. Recent advancements in genetic engineering have produced transgenic trees with reduced lignin content and/or modified lignin structure without compromising growth traits. Here, three engineered poplar varieties are evaluated as feedstocks using a biocompatible one-pot deep eutectic solvent-mediated process that integrates biomass fractionation and enzymatic saccharification within a single reactor, eliminating water washing and reconditioning. All transgenic poplars exhibit higher fermentable sugar yields than wild-type (WT) trees. Notably, QsuB poplar, incorporating 3,4-dihydroxybenzoate in lignin, achieves the highest glucose conversion yield of 91.3% (vs. 73.0% from WT). AT5 and MdCHS3 poplars, incorporating ferulate esters and naringenin, also demonstrate improved glucose yields (86.7 and 84.7%, respectively), confirming reduced biomass recalcitrance. Additionally, residual lignins are valorized via hydrogenolysis into phenolic compounds, with comparable alkylphenol production across all lines. These findings demonstrate that the transgenic poplar lines not only serve as superior feedstocks for sugar conversion but also provide a rich resource for phenolic compound production, enhancing the operational and economic viability of integrated biorefinery processes.

biomasses↗

DOE OSTI2025

Fossil Energy in the Hydrogen Economy – A Carbon-Water-Energy Nexus Adaptive Evaluation Platform

This project develops tools to evaluate fossil energy within the hydrogen economy. In particular, the project seeks to explore the Carbon-Water-Energy Nexus and develop adaptive evaluation tools. The primary goal of this project was to evaluate fossil-based hydrogen production methods with an emphasis on their sustainability, particularly with respect to carbon emissions and water use. The overall technical objectives that guided this evaluation consisted of 1) technology assessment, which sought to establish a comprehensive baseline of existing and emerging technologies for the generation, transportation, storage, and end use of hydrogen derived from fossil fuels, 2) carbon footprint analysis through quantification and analysis of carbon emissions associated with these hydrogen technologies, and identification of novel strategies and technologies that can effectively mitigate the carbon footprint, 3) water intensity assessment by evaluating the water needs (water-energy nexus) associated with different fossil fuel-based hydrogen technologies and proposing strategies to reduce water use, thus ensuring sustainable resource management, and 4) review of regulatory, policy and economic trends were examined to provide an overview of the factors influencing the adoption and integration of fossil fuel-derived hydrogen technologies into current energy markets. Beyond the technical outcomes, this project contributed to 5) education and workforce development through targeted training and educational opportunities for engineering students, preparing the next generation of professionals with technical, economic, and regulatory expertise in the hydrogen economy. Ultimately, this effort was intended to train the future workforce to provide useful insights to policymakers, industry stakeholders, and the broader energy community to facilitate informed decisions and responsible development within the hydrogen economy.

08 HYDROGEN↗

DOE OSTI2022

Large-Scale Simulation of Regional Demand Flexibility Implementation and Customer Economic Impact

The Distribution System Operator with Transactive (DSO+T) study conducted a large-scale simulation of over 60,000 customers in a region the size of Texas to demonstrate the effective coordination of distributed energy resources (DERs) in commercial and residential buildings. The integrated simulation included both the bulk (wholesale generation and transmission) and distribution systems. The DERs (including batteries, electric vehicles, air conditioning, and water heaters) participated in a transactive energy retail market that was integrated into an existing competitive wholesale market. The engineering and economic performance of the resulting demand flexibility was evaluated over annual simulations for both moderate and high renewable generation scenarios. A detailed parametric cost model was developed to enable detailed economic analysis of key stakeholders. In addition, fixed and dynamic customer tariffs were designed and applied to the customer population. This allowed the impact on annual customer bills to be analyzed for various building types (residential versus commercial; single- versus multi-family). This paper presents results showing the relative flexibility of batteries, electric vehicles, and building loads throughout the year and under different renewable scenarios. This feeds a detailed breakdown of the impact this flexibility has on the operating costs of the grid and the resulting net economic benefit. Finally, the study showed that practically all customer classes (including non-participating customers) save money under the proposed demand flexibility scheme. The study found overall net annual economic savings of $3.3-5.0B for a region the size of Texas equating to average customer bill savings of 10-16%.

Reeve, Hayden M.↗

NASA NTRS2005

Challenges in Predicting Planetary Granular Mechanics

Through the course of human history, our needs in agriculture, habitat construction, and resource extraction have driven us to gain more experience working with the granular materials of planet Earth than with any other type of substance in nature, with the possible exception being water. Furthermore, throughout the past two centuries we have seen a dramatic and ever growing interest among scientists and engineers to understand and predict both its static and rheological properties. Ironically, however, despite this wealth of experience we still do not have a fundamental understanding of the complex physical phenomena that emerge even as just ordinary sand is shaken, squeezed or poured. As humanity is now reaching outward through the solar system, not only robotic ally but also with our immediate human presence, the need to understand and predict granular mechanics has taken on a new dimension. We must learn to farm, build and mine the regoliths of other planets where the environmental conditions are different than on Earth, and we are rapidly discovering that the effects of these environmental conditions are not trivial. Some of the relevant environmental features include the regolith formation processes throughout a planet's geologic and hydrologic history, the unknown mixtures of volatiles residing within the soil, the relative strength of gravitation, ~d the atm9spheric pressure and its seasonal variations. The need to work with soils outside our terrestrial experience base provides us with both a challenge and an opportunity. The challenge is to learn how to extrapolate our experience into these new planetary conditions, enabling the engineering decisions that are needed right now as we take the next few steps in solar system exploration. The opportunity is to use these new planetary environments as laboratories that will help us to see granular mechanics in new ways, to challenge our assumptions, and to help us finally unravel the elusive physics that lie behind complex granular phenomena. Toward these goals, a workshop was held recently at NASA's John F. Kennedy Space Center, attracting over a hundred scientists and engineers from around the world and from a broad crosssection of scientific and engineering disciplines. This talk will provide an out-briefing from that workshop, communicating some of its early findings in regard to lunar and Martian exploration: (1) the requirements for working with granular materials, (2) the challenges that granular materials will pose, (3) the environmental conditions that affect granular mechanics, (4) instruments and measurements that are needed on the Moon and Mars to support granular material research, and (5) some of the possible research avenues that should be pursued.

Metzger, Philip T.↗

NASA NTRS2012

Nanoporous Materials in Atmosphere Revitalization

Atmospheric Revitalization (AR) is the term the National Aeronautics and Space Administration (NASA) uses to encompass the engineered systems that maintain a safe, breathable gaseous atmosphere inside a habitable space cabin. An AR subsystem is a key part of the Environmental Control and Life Support (ECLS) system for habitable space cabins. The ultimate goal for AR subsystem designers is to 'close the loop', that is, to capture gaseous human metabolic products, specifically water vapor (H2O) and Carbon dioxide (CO2), for maximal Oxygen (o2) recovery and to make other useful resources from these products. The AR subsystem also removes trace chemical contaminants from the cabin atmosphere to preserve cabin atmospheric quality, provides O2 and may include instrumentation to monitor cabin atmospheric quality. Long duration crewed space exploration missions require advancements in AR process technologies in order to reduce power consumption and mass and to increase reliability compared to those used for shorter duration missions that are typically limited to Low Earth Orbit. For example, current AR subsystems include separate processors and process air flow loops for removing metabolic CO2 and volatile organic tract contaminants (TCs). Physical adsorbents contained in fixed, packed beds are employed in these processors. Still, isolated pockets of high carbon dioxide have been suggested as a trigger for crew headaches and concern persists about future cabin ammonia (NH3) levels as compared with historical flights. Developers are already focused on certain potential advancements. ECLS systems engineers envision improving the AR subsystem by combining the functions of TC control and CO2 removal into a single regenerable process and moving toward structured sorbents - monoliths - instead of granular material. Monoliths present a lower pressure drop and eliminate particle attrition problems that result from bed containment. New materials and configurations offer promise for lowering cabin levels of CO2 and NH3 as well as reducing power requirements and increasing reliability. This chapter summarizes the challenges faced by ECLS system engineers in pursuing these goals, and the promising materials developments that may be part of the technical solution for challenges of crewed space exploration beyond LEO.

Hernandez-Maldonado, J.↗

NASA NTRS2019

Current NASA In-Situ Resource Utilization (ISRU) Strategic Vision

Perform development to TRL 5/6 through ground demonstration in relevant environment. Perform component/subscale subsystem flight demonstrations on small/mid-size landers. Assess and characterize water in volatiles in lunar polar shadowed regions and craters. Reduce risk of ISRU for mission critical consumables through Integrated End-to-End Flight Demonstrations (pilot scale). Establish initial Human Mission Scale production capability to promote sustainable operations and as anchor for commercial involvement. Identify and characterize polar region environment and resources/volatiles for Science and future Exploration/Commercial applications. Provide ground-truth physical, mineral, and water/volatile resource characteristic information at multiple locations to provide geological context for science-focused theories of volatile placement and initial mining assessments.Test technologies and processes to reduce risk of future extraction/mining systems. Quantify concentration and lateral/vertical distribution of resources/volatiles. Utilize ISRU capabilities to Extend and Enhance Human Lunar Exploration Missions. Provide oxygen (and fuel) to enable reusable human lunar lander (10+ MT/yr O2)Process carbon-based crew waste/trash into gases and propellants; can reduce logistics while minimizing public perception issues (alternative is conversion to radiation shielding). Scavenge unused propellants and hardware from spent landers. Metal extraction from regolith as feedstock for in situ and in space manufacturing demonstrations. Civil engineering and construction aimed at future outpost/infrastructure build-up. Develop and Demonstrate ISRU for Human Mars Missions. ISRU for propellant production (10-15 MT/yr); Liquefy, store, transfer, and refuel ascent vehicle. Use Moon for operational experience and mission validation for Mars: Pre-deployment & remote activation and operation without crew. Storing and transferring mission consumables Landing crew with empty tanks with ISRU propellants already made and waiting. Support/Promote Commercialization of Space. Large scale polar ice mining (100+ MT/yr water)O2/H2 propulsion for landers/cis-lunar transportation with surface and in space depots. In situ construction and energy expansion at mining and human outpost site(s). ISRU Ground Development. Develop and advance ISRU technologies to enable acquisition of resources and processing into mission consumables. Utilize Multi-center collaboration with a portfolio that includes internal NASA work, external contracts, and collaborative agreements/partnerships. Where appropriate, develop lunar ISRU components and subsystems with a Mars-forward application. Engage industry through public-private partnerships to lay the foundation for long-term lunar and space economic development. Spin-in/spin-out technologies for terrestrial applications and industry (mining, oil & gas, alternative energy, construction). Flight Demonstration Path to Operational ISRU. Utilize small demonstrations with near off-the-shelf hardware to obtain critical information quickly on lunar resources and operations. Demonstrate critical technologies and processes that interact with lunar materials and environments. Perform 'pilot plant' demonstrations at architecture relevant scales and durations to reduce the risk for ISRU-provided products for critical human mission applications.

In-situ Resource Utilization↗

DOE OSTI2023

Water resource recovery modelling 2021 (WRRmod2021 conference)

Our society is transitioning fast into the digital age, spurred by development of cheap and new sensing technology, breakthroughs in computing, and development of efficient algorithms for optimization. This transition is also visible in the field of wastewater treatment and is driving new model developments, especially by exploiting the large data sets available with many utilities. Not surprisingly, WRRmod2021 had featured a strong session on ‘data-driven models and digitalization’ focused on this hot topic. At the same time, engineering practice calls for more robust models for performance evaluation and optimization of both conventional facilities and innovative processes. As a result, the WRRmod2021 program also exhibited sessions on modelling of new process units (e.g., aerobic granular sludge), modelling of the nitrogen cycle, and integrated/plant-wide modelling.

54 ENVIRONMENTAL SCIENCES↗