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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS2000

Separation Control at Flight Reynolds Numbers: Lessons Learned and Future Directions

Active separation control, using periodic excitation, was studied experimentally at high Reynolds numbers. The effects of compressibility, mild sweep, location of excitation slot and steady momentum transfer on the efficacy of the method were identified. Tests conducted at chord Reynolds numbers as high as 40 x 10(exp 6) demonstrated that active control using oscillatory flow excitation can effectively delay flow separation from, and reattach separated flow to aerodynamic surfaces at flight conditions. The effective frequencies generate one to four vortices over the controlled region at all times, regardless of the Reynolds number. The vortices are initially amplified by the separated shear-layer, and after initiating reattachment, the strength of the vortices decay as they are convected downstream. Large amplitude, low frequency vortices break down to smaller ones upon introduction at the excitation slot. The effects of steady mass transfer were compared to those of periodic excitation. It was found that steady blowing is significantly inferior to periodic excitation in terms of performance benefits and that the response to steady blowing is abrupt, and therefore undesirable from a control point of view. Steady suction and periodic excitation are comparable in effectiveness and both exhibit a gradual response to changes in the magnitude of the control input. The combination of weak steady suction and periodic excitation is extremely effective while the addition of steady blowing could be detrimental. Compressibility effects are weak as long as separation is not caused by a shock-wave/boundary-layer interaction. The undesirable effects of the shock-induced separation could be alleviated by the introduction of periodic excitation upstream of the shock wave, inside the region of supersonic flow. The effects of mild sweep were also studied and periodic excitation was found to be very effective in reattaching three-dimensional separated flow. Scaling laws that correlate 2D and 3D controlled flows were tested and verified. Several performance benefits could be gained by applying the method to existing configurations, but it is expected that the full potential of the method can only be realized through the design of new configurations. A comprehensive, fully turbulent, database was generated in order to guide the development, and enable validation, of candidate unsteady CFD design tools.

Pack, LaTunia G.↗
DOE OSTI2018

Toward a Multimodal-Deep Learning Retrieval System for Monitoring Nuclear Proliferation Activities

As the amount of available data increases, the human ability to locate, process, and analyze it is strained and eventually overwhelmed. To address this challenge for nonproliferation analysts, the authors have been creating a large-scale multimodal retrieval system to help analysts triage and search open source science, technology, and news data for indicators of nuclear proliferation capabilities and activities. The system relies on a set of deep neural networks (DNNs) trained to evaluate conceptual similarities across data modalities, such as text, image, and video. These DNNs can be used to search and prioritize data, according to a nuclear fuel cycle (NFC) process template, that are conceptually closest to the seed query items regardless of data modality. The DNNs have been trained to map conceptually related words, sentences, and images to nearby points in a multimodal feature space, enabling intra- and intermodal retrieval via nearest-neighbor calculations to seed query points. The authors evaluate the system’s ability to retrieve NFC-related data that have been purposely hidden in collections of unrelated background data. They demonstrate quantitative and qualitative results for text-to-image, image-to-image, and image-to-video retrievals. This paper discusses data challenges confronting nonproliferation analysts, describes the DNNs designed to retrieve multimodal data that are proximal in the semantic space, and demonstrates their effectiveness by applying the DNNs to nonproliferation-specific multimodal data sets.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2015

German research and development for high level waste in light of the new site selection process - 15516

The German government decided 50 years ago, that radioactive waste is to be disposed of in Deep Geologic Repositories, preferably in a salt rock formation. Soon after, in 1967, research in the Asse salt mine was initiated. Since then substantial progress has been achieved in the development of the radioactive waste disposal programme in Germany. For a geologic repository for High Level Waste in salt a reference concept has been developed, which represented the radioactive waste management processes from transport of High Level Waste and Spent Nuclear Fuel to an interim storage site, waste conditioning and repackaging for disposal, to emplacement of the waste packages. The feasibility of the reference concept has been proven by demonstration tests for all relevant equipment: a pilot conditioning plant has been built as well as the main equipment for the entire transport chain including the shaft transport and emplacement technologies for heavy loads fulfilling strict requirements for nuclear and mining safety. Also the backfilling technology has been optimised for the purposes of a repository for radioactive waste. Finally, tests have been performed to verify thermo-mechanical models for the host rock. The demonstration tests have been performed to an extent which even would allow immediate licensing of the repository and the employed equipment. The Research and Development work was completed by further optimisation of the reference concept. Construction and operation of deep geologic repositories for low and intermediate level radioactive wastes in Germany benefited from the above mentioned but also stimulated the knowledge and experience build-up for the repositories for High Level Waste. Despite the well progressed work for a deep geologic repository in salt R and D work in Germany for already a long time also considered other host rock formations. While work for crystalline rock mainly consisted of relatively small contributions to international research projects due to the limited occurrence of suitable sites in Germany, projects and developments for repositories in clay formations have had an increasing contribution to the overall Research and Development work for radioactive waste repositories in Germany. In July 2013 a new site selection act was put into force, which set the initiating conditions for the German programme on radioactive waste management. Principally, a process was initiated to search for a site for a deep geologic repository for High Level Waste independent from earlier decisions. This means that a site shall be determined without predetermination by earlier decisions. Nevertheless, to enable a sound decision for a site selection it is necessary to be able draw back on the knowledge and experience from earlier activities. Otherwise, tedious learning processes would have to be experienced again. Since efforts to open up a site selection process again grew since the late 1990's projects had been implemented timely to capture existing knowledge. The paper at hand describes the achievements of R and D activities in Germany, the change of radioactive waste management policy and the endeavours to maintain the achievements. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

A Molecular View of Methane Activation on Ni(111) through Enhanced Sampling and Machine Learning

A combination of machine learned interatomic potentials (MLIPs) and enhanced sampling simulations is used to investigate the activation of methane on a Ni(111) surface. The work entails the development and iterative refinement of MLIPs, initially trained on a dataset constructed via ab initio molecular dynamics (AIMD) simulations, supplemented by adaptive biasing forces, to enrich the sampling of catalytically relevant configurations. Our results reveal that by incorporating collective variables that capture the behavior of the reactant molecule, as well as additional frames that describe the dynamic response of the catalytic surface, it is possible to enhance considerably the accuracy of predicted energies and forces. By employing enhanced sampling schemes in the refinement of the MLIP, we systematically explore the potential energy surface, leading to a refined MLIP capable of predicting DFT-level energies and forces and replicating key geometric characteristics of the catalytic system. The resulting free energy landscapes at several temperatures provide a detailed view of the thermodynamics and dynamics of methane activation. Specifically, as methane approaches and dissociates on the catalytic surface, the process involves the dynamic interplay of CH 4 and the Ni catalyst that includes both enthalpic and entropic contributions. The progression towards the transition state involves an CH 4 moiety that is increasingly restrained in its ability to rotate or translate, while the stage following the transition state is characterized by a notable rise of the Ni atom that interacts with the cleaved C–H bond. Furthermore, this leads to an increase in the mobility of the adsorbed species, a feature that becomes more pronounced at higher temperatures.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2004

Winds, Water Budgets and Stable Isotopes in Tropical Cyclones using TRMM and QUICKSCAT

Water vapor is the most abundant greenhouse gas in the atmosphere. Changes in its concentration and distribution are controlled by the hydrologic cycle. Because of its capacity to absorb and emit long wave radiation, release latent heat during condensation in storms and reflect short wave radiation when clouds form it has a major impact on Global climate change. The stable isotope ratios of water are H20 H2l6O and H0 H2l6O. These ratios change whenever water undergoes a phase change. They also change in both rain and water vapor whenever an air parcel is exposed to rain. In addition the relative changes in the two ratios differ as a &nction of the relative humidity. In short, the stable isotope ratios in water vapor in the atmosphere contain an integrated history of the processes affecting the concentration and distribution of water vapor in the atmosphere. Therefore the measurement and interpretation of changes in these stable isotope ratios are a powerful tool matched by no other method in tracing the transport history of water in the atmosphere. Our initial studies under this grant focused on the changes of the stable isotope ratios of precipitation and water vapor in tropical cyclones. The changes in time and space were found to be very large and to trace the transport of water in the storms reflecting changes in basic structural features. Because the stable isotope ratios of rains from tropical cyclones are so low flooding associated with land falling tropical cyclones introduces a negative isotopic spike into the coastal surface waters. In addition the stable isotope ratios of water vapor in the vicinity of tropical cyclones is anomalously low. This suggests that carbonate shelled organisms such as ostracoda living in coastal waters have the potential to record the isotopic spike and thereby provide a long term record of tropical storm activity in sediment cores containing fossil shells. Likewise, tree rings in coastal environments offer a similar potential. We have analyzed the oxygen isotopic composition of ostrcoda shells formed in the floodwaters of Tropical Storm Allison (2001) and discovered the negative isotopic 1 16 spike. Because we had learned that storm activity has a major impact on the stable isotope ratios of water vapor in the tropics and sub-tropics we decided to analyze the isotopic compositions of water vapor in different locations in the tropics. We did this in Puerto Escondido, Mexico in July 1998, near Kwajalein Island in the Pacific in 1999 as part of a TRMM summer field program and in 2001 in Key West, Florida as part of the CAMEX 4 summer field program. Our isotopic studies along with our earlier tropical cyclone studies showed that the low isotopic ratios in water vapor induced by exposure to rains the storms persisted for 48 hours often far away from the original storm site. We also noted that positive isotopic spikes were introduced into atmospheric water vapor if winds were high and extensive sea spray was present. These findings have a significant impact on the interpretation of the stable isotope studies of tropical ice cores found in the high mountain regions of the tropics. The assumption made in interpreting the ice core record is that the source water vapor evaporated from the sea surface is in near isotopic equilibrium with the seawater and undergoes a decrease during its transport that reflects the change in temperature from the sea surface to the site of the ice core. Because an additional isotopic depletion occurs at the sea surface source area that depends on the intensity, duration and size of the tropical rain system the isotopic variations found in the ice cores must take into account changes in past storm activity in the tropics. These systems must be an important source of water vapor to the ice cores because they charge the troposphere with water vapor to a far greater vertical height than evaporation in quiescent regions. Finally, an interest in increased heat transfer in thnterior of tropical cyclones resulting from greater amounts of sea spray is a topic of considerable interest to the research community. Increases in sea spray may be related to rapid changes in the intensity of hurricanes, a feature of hurricanes that currently is very poorly forecast. Project CBLAST of the Hurricane Research Division of NOAA is an active program that uses P3 research aircraft to evaluate this problem. An instrument has been designed and built at the University of Houston that will be placed on the P3 research aircraft during the 2004 hurricane season. It continuously measures the salt content of rain in hurricanes. Changes in the salt content of the rains should reflect the abundance of sea spray at the sea surface. In this way maps of sea spray intensity in hurricanes may be forthcoming. This should help computer modelers who simulate hurricanes to better understand the potential of changes in sea spray to change the intensity of hurricanes. The cost of designing, building and installing this instrument was borne largely by funding from this NASA grant. A list of presentations at national meetings and publications that were as the result of funding from this NASA grant are found in the report.

Lawrence, James R.↗
DOE OSTI2024

Deep Learning for Full Waveform Inversion of Elastic Active-Source Seismic Data to Estimate P-Wave Velocity Models

Seismic imaging methods are critical for Global Security and Energy & Homeland Security missions and activities that rely on subsurface characterization, but traditional methods remain computationally expensive and require significant labor hours and expertise to execute. Within the past few years, machine learning (ML), namely deep learning (DL), has been used to develop data-driven end-to-end full waveform inversion (FWI) methods to estimate 2D P-wave velocity (Vp) models in a fraction of the time as conventional FWI. These methods, however, are trained on simplistic acoustic wave seismic data and Vp models that are not realistic nor representative of real-world observations, leaving a large gap between the state-of-the-art and deployable, feasible, and practical DL FWI methods. Here, we generate a synthetic active-source, 3D, elastic wave seismic data set and a variety of Vp models with realistic geologic structure for training DL FWI methods. We evaluate six different methods that have performed well for acoustic DL FWI or medical imaging tasks using our more realistic dataset. We find that these six trained models do not match the performance of published acoustic end-to-end DL FWI methods, indicating more training data may be needed, physics may need to be incorporated to achieve good accuracy at the sacrifice of the end-to-end advantage, and/or novel methods need to be developed to enable end-to-end DL FWI methods to perform well for real-world seismic data.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2021

The phylogenetic roots of addiction: compulsive drug seeking, natural and drug-sensitive reward, and the acquisition of learned habits

Our rational faculties permit us humans to maximize the utility of our actions. We perform a fundamental type of cost-benefit analysis in which we frame a problem, assign values to the different paths, and then choose from among a set of available options, the course that promises the most favorable outcome. So why then does addiction appear to be so impervious to the associated costs, so unaffected by undesired consequences, and ultimately so resistant to cognitive oversight? The answer may likely be found in the fact that the drivers for compulsive drug seeking and drug taking are located in affective brain circuits, circuits that are structured and patterned by learning with repeated activation. These deep processes exhibit significant resistance to control by our cognitive faculties. The general consensus is that addiction arises from mechanisms that overvalue the magnitude of reward, discount the associated risks, and thereby bias individuals towards compulsive pursuit of addictive drugs. Behavioral disruption and dependence appear to arise at the intersection of a number of connected but separate phenomena: expectations for the occurrence of specific events, behaviors that seek encounters with them, the ability to notice and learn nonrandom, co-occurring conditions, the prediction and valuation of consequences, the forming of enduring memories, and the drivers of focused behavior through compulsion, habits, and acquired routines. It is important to recognize that each one of these individual faculties are present and well developed across the entire phylogenetic tree of bilateral metazoans. The goal of this special volume is dedicated to exploring the degree to which inherent elements can account for addiction and addiction-associated phenomena. In much of the literature on addiction, the underlying processes are often viewed as distinctly mammalian, arising, in part, from the strong cognitive capacities of this taxon. Some phenomena may even be regarded to exist only in primates, or even solely in humans. This supposition arises from the fact that studies are conducted almost exclusively in mammals and primates, while evolutionary antecedents of the behavior are rarely considered. A more comprehensive perspective that examines drug reward and reinforcement in a wider range of organisms demonstrates that many of the component traits are actually well developed across the greater metazoan lineage, and they may well predate the emergence of a mammalian clade by a wide margin. The collection of papers assembled here supports the notion that the capacity to associate cues and quences has not arisen in mammals de novo. Rather, the neural mechanisms for detecting contingencies and for predicting future outcomes are very deeply rooted across broad phylogenetic divisions. Our understanding of an ability to associate paired events has been enriched by work in invertebrate preparations in both classical and operant conditioning scenarios [Cook and Carew, 1986, 1989a, 1989b]. The ability to learn allows us to connect cues and behavioral actions to their associated consequences. Pavlovian conditioning enriches surrounding cues with predictive value. Outcomes with positive valence generate appetitive responses and approach to the associated cues, while those perceived as aversive bring cue avoidance and withdrawal. Humans are not the only life forms capable of such short- and long-term modulations of behavior

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2023

The Trash Compaction Processing System (TCPS) Technology Demonstrations Science Objectives and Requirement Definitions

Throughout the Next STEP Phase A and Phase B, the Trash Compaction Processing System (TCPS) is being developed for a technology demonstration (TD) on the International Space Station (ISS) in 2025. For Phase A, two contractors built proof-of-concept hardware. One contractor was chosen to build the TD hardware for Phase B. Both Phase A lessons learned and risk reduction activities at Ames Research Center (ARC) were used to write the TD science objectives, scope, and requirements. The work at ARC aims to retire technical risks and provide design data to TCPS developers and the ISS system integrators. This paper will summarize the lessons learned from the proof-of-concept hardware, the risk reduction activities, and how these lessons learned form the basis of the TD requirement matrix.

TCPS↗
DOE OSTI2025

Biosynthesis of bioprivileged, linear molecules via novel carboligase reactions

Over the award period, we made progress on the three aims. We screened twenty-five carboligases for activity coupling twenty-one possible -keto acids (Aim 1). The carboligases were selected across a diverse set of protein sequences. Using Q-Exactive UHPLC-MS, we tested a total of 210 coupled products per enzyme and generated a dataset of 5250 enzyme-substrate activity relationships. We identified multiple enzymes that had activity for synthesizing suberic acid and heptanoic acid (Aim 2). We built a random forest model for predicting the activity of each enzyme toward substrates on which it was not tested using the data from Aim 1. Finally, we evaluated growth defects that occurred due to expression of different carboligases in E. coli (Aim 3). We were able to identify specific metabolites and putative pathways that, when supplemented in the media, recovered the growth defect associated with the presence of specific carboligases. We are in the process of publishing two manuscript describing the methods for high-throughput screening of enzyme promiscuity, using machine learning to predict activity on untested substrates, and enzyme activity data we collected. This project has produced enabling data for biosynthesis of a range of new-to-nature compounds to support biomanufacturing.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

2021 ROMANIA TRANSPORT SECURITY TABLE-TOP EXERCISE (TTX) – LESSONS LEARNED AND GOOD PRACTICES

During the period of 15-18 March 2021, the IAEA conducted a national workshop addressing the security of radioactive material in transport. The workshop was jointly hosted by the Romanian regulatory authority and the General Inspectorate of Romanian Gendarmerie. The workshop assisted Romania in improving its capability to evaluate the ability of response forces to counter a malicious act against radioactive material in transport. The event consisted of briefings, exercises, a demonstration of transport security equipment, and a transport security table-top exercise (TTX). The workshop was conducted in a virtual-hybrid format in such a way as to meet the COVID-19 related requirements in compliance with Romania’s guidelines. This paper provides an overview of the workshop’s activities, lessons-learned, and good practices related to the transport security TTX exercises.

Maican, Catalin↗
DOE OSTI2023

Product Consistency Test Results for the LAW ML1 Glasses

This report summarizes the chemical analysis of Product Consistency Test (PCT) leachates received from Pacific Northwest National Laboratory (PNNL). The leachates are from a series of quenched simulated nuclear waste glasses designated Low-Activity Waste Machine Learning (LAW ML1) glasses that were designed and fabricated at PNNL. The reported data will be used in the development, validation, and implementation of enhanced property/composition models for waste glass vitrification at Hanford. The elemental release for the study glasses is reported as normalized concentration NCi. NCi of several elements was computed for both the target and measured glass compositions, which were similar, resulting in no significant differences. Several of the glasses exhibited NC B , NC Na , and/or NC Si values that were greater than the Waste Treatment Plant (WTP) low-activity waste constraint of 4 g/L. All reference glasses included with the study glasses had measurements that fell within the expected ranges.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2010

The Evolution of Extravehicular Activity Operations to Lunar Exploration Based on Operational Lessons Learned During 2009 NASA Desert RATS Field Testing

This paper will present options to evolutionary changes in several philosophical areas of extravehicular activity (EVA) operations. These areas will include single person verses team EVAs; various loss of communications scenarios (with Mission Control, between suited crew, suited crew to rover crew, and rover crew A to rover crew B); EVA termination and abort time requirements; incapacitated crew ingress time requirements; autonomous crew operations during loss of signal periods including crew decisions on EVA execution (including decision for single verses team EVA). Additionally, suggestions as to the evolution of the make-up of the EVA flight control team from the current standard will be presented. With respect to the flight control team, the major areas of EVA flight control, EVA Systems and EVA Tasks, will be reviewed, and suggested evolutions of each will be presented. Currently both areas receive real-time information, and provide immediate feedback during EVAs as well as spacesuit (extravehicular mobility unit - EMU) maintenance and servicing periods. With respect to the tasks being performed, either EMU servicing and maintenance, or the specific EVA tasks, daily revising of plans will need to be able to be smoothly implemented to account for unforeseen situations and findings. Many of the presented ideas are a result of lessons learned by the NASA Johnson Space Center Mission Operations Directorate operations team support during the 2009 NASA Desert Research and Technology Studies (Desert RATS). It is important that the philosophy of both EVA crew operations and flight control be examined now, so that, where required, adjustments can be made to a next generation EMU and EVA equipment that will complement the anticipated needs of both the EVA flight control team and the crews.

Bell, Ernest R., Jr.↗
NASA NTRS2019

UAS Service Supplier Checkout: How UTM Confirmed Readiness of Flight Tests with UAS Service Suppliers

NASA collaborated with industry partners to develop and test the small Unmanned Aircraft System (sUAS) Traffic Management (UTM) research platform, a software prototype used for developing airspace integration requirements for sUAS operations. The lessons learned from these activities will help inform the Federal Aviation Administration (FAA) on what is needed to safely manage sUAS operations. A core component of the UTM platform is the UAS Service Supplier (USS), which acts as a communications bridge to meet the regulatory and operational requirements. As the UTM partners began USS flight tests, NASA found that it was difficult to get all USSs functioning at comparable quality levels to ensure successful flight tests. Also, NASA anticipated that the FAA would encounter similar challenges when they begin to register USSs for operational use. These realizations led to the development of USS Checkout, a set of processes and tools designed to increase flight test efficiency. We learned that a good USS Checkout process is balanced for simplicity versus test coverage, and is amenable to automation. We also learned that when USS Checkout is a USS prerequisite for flight tests, flight tests were more efficient and effective.

Smith, Irene Skupniewicz↗
NASA NTRSDate not supplied

Advancing Open Source Science Initiatives Through Public-Private Partnerships

Collaboration is fundamental to advancing open science within the science community. With the recent developments in technology and research, the establishment of formal partnerships between the private sector and government agencies are needed to bridge the knowledge gaps and expedite the time to actionable science. NASA’s Interagency Implementation and Advanced Concepts Team (IMPACT) seeks to address this challenge by establishing non-reimbursable Space Act Agreements with industry leaders in cloud computing, artificial intelligence (AI) and machine learning. The purpose of these agreements is to advance open source science initiatives in the areas of data discovery, access and use of high value NASA science data sets on the cloud. As well as, jointly work on common research problems to accelerate the development and adoption of new AI technologies. Current success stories include co-locating NASA datasets from multiple science disciplines on one platform using Amazon Web Services Open Data Registry, developing AI Foundation Models for Science with IBM and co-hosting training workshops and tutorials for the science community aimed at providing hands-on experience with using NASA data and AI models on the cloud. In summary, we will present an overview of our partnerships supporting open source science initiatives, describe current activities and lessons learned that may be useful to others considering similar partnerships with the private sector.

Elizabeth Fancher↗
NASA NTRSDate not supplied

2023 NASA SmallSat In-Person LEARN Forum: Announcements

NASA’s SmallSat LEARN Forum is an activity aimed at providing the NASA SmallSat Community with collaboration resources. LEARN stands for Learning from Experiences, Achievements, and Resolution Navigation and through the forum attendees share and learn together as a community to become smarter implementers of small spacecraft missions. Held October 11-12, the Annual In-Person LEARN Forum announcements presentation summarizes current and upcoming events and solicitations for the community.

Bruce D Yost↗
DOE OSTI2018

Integrated pre-feasibility study for CO 2 geological storage in the Cascadia Basin, offshore Washington State, British Columbia

The Cascadia CarbonSAFE project conducted a pre-feasibility study to evaluate technical and nontechnical aspects of storing 50 million metric tons (MMT) of carbon dioxide in a safe, ocean basalt reservoir offshore Washington State and British Columbia. Sub-seafloor basalts are very common on Earth and enable geological mineralization as a long-term storage mechanism, permanently sequestering the carbon in solid rock form. This project evaluated the offshore storage complex, developed potential industrial source/transport scenarios, built an inventory of existing geophysical/geological data and environmental monitoring capabilities, conducted laboratory studies and reservoir modeling to determine storage capacity, and analyzed economic factors, regulatory requirements, and project management risks. Our team included researchers at Columbia University in New York, Pacific Northwest National Laboratory (PNNL) in Washington, University of Victoria in British Columbia, University of California at Santa Cruz, and GHG Underground in Maine, as well as collaborators at University of Iceland in Reykjavik and University of Washington in Saint Louis. In the study region, large emitters (>100,000 MT/year) generate a total of approximately 40 MMT annually from stationary sources, such as power plants, refineries, ammonia production, and mineral processing plants. Five potential industry source/transport scenarios were identified (three in U.SA S. and two in Canada) to potentially provide 50 MMT of carbon dioxide to the offshore reservoir. One scenario included net carbon-negative sources that would reduce atmospheric levels. The inventory of existing data illustrated that basalt properties in the region are potentially beneficial for long-term storage. Permeability is on the order of 0.1 to 1 Darcies within the uppermost 600 m of ocean crust and density-derived porosity reaches 10–20% in thin layers that provide act as flow channels and provide access to porous and permeable basalt. Fine-grained sediments overlying basalt provide a low-permeability barrier separating the storage reservoir from the overlying ocean. Subsurface monitoring of the storage complex benefits from a unique opportunity close proximity of to the nearby NEPTUNE cabled seafloor observatory, which actively transmits data to shore and could be used to monitor reservoir properties. Injection pressure changes, reservoir chemistry, seismicity, well head corrosion, and potential leakage monitoring would be feasible in real time. Using existing data and published models, the STOMP-CO 2 modeling code developed at PNNL was used to simulate carbon dioxide injection, storage, and mineralization in the reservoir. Preliminary simulations indicate that a 50 MMT carbon dioxide plume injected over a 20-year period remains well within the reservoir area, both laterally and vertically, for at least a 50-year period of post-injection monitoring. Laboratory studies on core samples from Cascadia measured dissolution rates in CO 2 –basalt–seawater mixtures and indicated large variability in rates with the potential for complete mineralization. Compared to published data, the dissolution rate measured in these samples is faster, decreasing the time until full conversion to carbonate minerals would occur. Adding geochemical reactivity in the STOMP-CO 2 model indicates that carbon dioxide would be fully converted to carbonate minerals in 135 years or less after injection ceases. The project assessed the viability and costs for the five scenarios using either dedicated offshore pipelines or shipping vessels. Carbon dioxide capture costs were not considered. Shipping incurred lower upfront CAPEX costs, and because most viable sources were located near the shore and waterways, shipping is preferred; no dedicated carbon dioxide pipelines exist in the region. The project also considered potential risks from mixed-use impacts on surrounding lands and ocean areas, such as active use by commercial and recreational fisherman, and other community considerations in planning for public engagement in the future. Other project risks were identified, including project management, permitting and compliance, and financing, as well as technical issues such as long-term instrumentation, plume migration, and model development. Geological concerns like reservoir permeability, seal, and induced seismicity held relatively low risk. The regulatory framework for offshore storage in the U.S. and Canada may be covered by general legal/regulatory programs, but is not yet fully defined. Existing programs appear to restrict the transportation of carbon dioxide across national boundaries (e.g., Canada to U.S.) and its sub-seabed disposal in some circumstances. Our assessment suggests that developing specific and separate pilot projects will help to advance the technical feasibility and regulatory requirements in each country, and lessons learned from such activities may be transferable elsewhere around the globe.

42 ENGINEERING↗
NASA NTRS2003

Conceptual Design of In-Space Vehicles for Human Exploration of the Outer Planets

During FY-2002, a team of engineers from TD30/Advanced Concepts and TD40/Propulsion Research Center embarked on a study of potential crewed missions to the outer solar system. The study was conducted under the auspices of the Revolutionary Aerospace Systems Concepts activity administered by Langley Research Center (LaRC). The Marshall Space Flight Center (MSFC) team interacted heavily with teams from other Centers including Glenn Research Center, LaRC, Jet Propulsion Laboratory, and Johnson Space Center. The MSFC team generated five concept missions for this project. The concept missions use a variety of technologies, including magnetized target fusion (MTF), magnetoplasmadynamic thrusters, solid core reactors, and molten salt reactors in various combinations. The Technical Publication (TP) reviews these five concepts and the methods used to generate them. The analytical methods used are described for all significant disciplines and subsystems. The propulsion and power technologies selected for each vehicle are reviewed in detail. The MSFC team also expended considerable effort refining the MTF concept for use with this mission. The results from this effort are also contained within this TP. Finally, the lessons learned from this activity are summarized in the conclusions section.

Adams, R. B.↗