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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
DOE OSTI2017

Post-Closure Environmental Sampling and Inspection at the Amchitka Island, Alaska, Site - 17251

In the 1960's and early 1970's, three underground nuclear tests were conducted on Amchitka Island, Alaska. In 1965, the US Department of Defense-in conjunction with the US Atomic Energy Commission (AEC)-conducted the first of these nuclear tests, Long Shot, to provide data that would improve US capabilities for detecting underground nuclear explosions. In 1969, AEC conducted the second test, Milrow, to explore the feasibility of detonating a much larger device. In 1971, AEC conducted the third test, Cannikin, which was the largest underground test ever conducted by the US. The Long-Term Surveillance Plan (LTSP) for the Amchitka, Alaska, Site details how the US Department of Energy Office of Legacy Management (LM) intends to fulfill its mission to protect human health and the environment at and around the Amchitka Island site. The LTSP calls for monitoring to be performed every 5 years, at least during the initial phase of the project. The purpose of the monitoring is to develop a baseline of activity concentrations for selected radionuclides in biota, water, and soil, both on Amchitka Island and at the reference location on Adak Island, approximately 322 kilometers (200 miles) northeast of Amchitka. In addition to the environmental monitoring activities, seven mud pit caps that contain diesel-contaminated soils are inspected. The plan for biological and water sampling (both seawater and freshwater) during the May 2016 sampling event was developed through close coordination with the primary stakeholders, including the Alaska Department of Environmental Conservation, the Aleutian Pribilof Islands Association, and the US Fish and Wildlife Service. The environmental sampling in 2016 is a continuation of LM's evaluation of Amchitka Island's environment. Previous results from similar monitoring programs in 2004 and 2011 indicate that the environment is not being impacted by radionuclide migration and uptake from the underground nuclear testing conducted beneath Amchitka Island; consequently, subsistence and commercial-catch seafood is safe for human consumption. The collection of biota samples (rockfish, Irish lords, greenling, and rockweed) for cesium-134 ({sup 134}Cs), cesium-137 ({sup 137}Cs), plutonium-239 ({sup 239}Pu), plutonium-240 ({sup 240}Pu), and freshwater and seawater samples for {sup 134}Cs, {sup 137}Cs, and tritium ({sup 3}H) was the primary objective of the 2016 sampling effort. Rockfish, Irish lords, and greenling are resident, nonmigratory fish species that spend their entire life cycle in the marine environment, and rockweed is an inter-tidal species that may concentrate cesium. The seawater samples were collected primarily to determine if leakage from the Long Shot detonation could be detected and, secondarily, to compare with the background seawater samples collected from Adak Island. Cesium isotopes are also being analyzed to better understand the potential impact that the Fukushima-Daiichi release might have on the Amchitka and Adak environments. The target detection limits used for the 2016 sampling are lower than those used in previous studies. The lower detection limits make it possible for LM to delineate background activity levels for the radionuclides of interest. Data from the 2016 sampling event go beyond assessing food safety and focus on detecting leakage from the underground nuclear explosions. Additionally, the baseline activity concentrations obtained for the reference area (Adak Island) will enable identification of quantitative statistical trends in the results of future sampling programs. Sampling programs conducted in 2021 and beyond will have an objective to assess the statistical trends of radioactivity levels in the Amchitka Island environment. (authors)

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

Optimization and Experimental Validation of Annular Finned PCM-HX for a Domestic Hot Water Heater Application

The load profile for domestic water heating is time-dependent and can result in high energy demand during peak operating times. Shifting this peak load can have significant environmental and economic impacts. Phase change material (PCM)-based thermal energy storage (TES) is a potentially useful technology for peak load shifting in domestic hot water (DHW) applications thanks to its high latent heat and energy density. In this study, an annular finned-tube PCM-HX design concept was optimized for a load-shifting TES unit to meet the Department of Energy standard for a medium-usage DHW heater using a resistance-capacitance model (RCM) integrated with a Multi-Objective Genetic Algorithm. The optimized design comprised 70 identical annular finned-tube PCM-HX units connected in parallel and utilizing RT62HC as the PCM. A single PCM-HX unit was prototyped and tested in a vertically oriented setup with upward heat transfer fluid (HTF) flow. The hot water supply time was defined based on a cutoff temperature of 51.7°C. The as-designed mass flow rate (1.5 g/s) was tested to assess the performance of the prototyped PCM-HX unit for RCM validation. For the experimental investigation, RTD sensor bundles measured HTF temperature at the PCM-HX inlet and outlet, and a Coriolis flow meter accurately measured the HTF mass flow rate. The simulated discharging power underpredicted the experimental result by about 12%, and the simulated hot water supply time underpredicted the experimental result by approximately 13% for the as-designed mass flow rate (1.5 g/s). The average deviation of the hot water supply temperature between the experimental and RCM results during the complete PCM solidification process was 1.3 K for the as-designed mass flow rate. The overall good agreement between the experimental and RCM results provides confidence that computationally efficient models such as RCM can be utilized for design optimization of PCM-HXs.

42 ENGINEERING↗
NASA NTRS2017

Characterizing DebriSat Fragments: So Many Fragments, So Much Data, and So Little Time

To improve prediction accuracy, the DebriSat project was conceived by NASA and DoD to update existing standard break-up models. Updating standard break-up models require detailed fragment characteristics such as physical size, material properties, bulk density, and ballistic coefficient. For the DebriSat project, a representative modern LEO spacecraft was developed and subjected to a laboratory hypervelocity impact test and all generated fragments with at least one dimension greater than 2 mm are collected, characterized and archived. Since the beginning of the characterization phase of the DebriSat project, over 130,000 fragments have been collected and approximately 250,000 fragments are expected to be collected in total, a three-fold increase over the 85,000 fragments predicted by the current break-up model. The challenge throughout the project has been to ensure the integrity and accuracy of the characteristics of each fragment. To this end, the post hypervelocity-impact test activities, which include fragment collection, extraction, and characterization, have been designed to minimize handling of the fragments. The procedures for fragment collection, extraction, and characterization were painstakingly designed and implemented to maintain the post-impact state of the fragments, thus ensuring the integrity and accuracy of the characterization data. Each process is designed to expedite the accumulation of data, however, the need for speed is restrained by the need to protect the fragments. Methods to expedite the process such as parallel processing have been explored and implemented while continuing to maintain the highest integrity and value of the data. To minimize fragment handling, automated systems have been developed and implemented. Errors due to human inputs are also minimized by the use of these automated systems. This paper discusses the processes and challenges involved in the collection, extraction, and characterization of the fragments as well as the time required to complete the processes. The objective is to provide the orbital debris community an understanding of the scale of the effort required to generate and archive high quality data and metadata for each debris fragment 2 mm or larger generated by the DebriSat project.

Shiotani, B.↗
NASA NTRS2005

A Methodology for Quantifying Certain Design Requirements During the Design Phase

A methodology for developing and balancing quantitative design requirements for safety, reliability, and maintainability has been proposed. Conceived as the basis of a more rational approach to the design of spacecraft, the methodology would also be applicable to the design of automobiles, washing machines, television receivers, or almost any other commercial product. Heretofore, it has been common practice to start by determining the requirements for reliability of elements of a spacecraft or other system to ensure a given design life for the system. Next, safety requirements are determined by assessing the total reliability of the system and adding redundant components and subsystems necessary to attain safety goals. As thus described, common practice leaves the maintainability burden to fall to chance; therefore, there is no control of recurring costs or of the responsiveness of the system. The means that have been used in assessing maintainability have been oriented toward determining the logistical sparing of components so that the components are available when needed. The process established for developing and balancing quantitative requirements for safety (S), reliability (R), and maintainability (M) derives and integrates NASA s top-level safety requirements and the controls needed to obtain program key objectives for safety and recurring cost (see figure). Being quantitative, the process conveniently uses common mathematical models. Even though the process is shown as being worked from the top down, it can also be worked from the bottom up. This process uses three math models: (1) the binomial distribution (greaterthan- or-equal-to case), (2) reliability for a series system, and (3) the Poisson distribution (less-than-or-equal-to case). The zero-fail case for the binomial distribution approximates the commonly known exponential distribution or "constant failure rate" distribution. Either model can be used. The binomial distribution was selected for modeling flexibility because it conveniently addresses both the zero-fail and failure cases. The failure case is typically used for unmanned spacecraft as with missiles.

Adams, Timothy↗
NASA NTRS2009

A Comparative Study of a 1/4-Scale Gulfstream G550 Aircraft Nose Gear Model

A series of fluid dynamic and aeroacoustic wind tunnel experiments are performed at the University of Florida Aeroacoustic Flow Facility and the NASA-Langley Basic Aerodynamic Research Tunnel Facility on a high-fidelity -scale model of Gulfstream G550 aircraft nose gear. The primary objectives of this study are to obtain a comprehensive aeroacoustic dataset for a nose landing gear and to provide a clearer understanding of landing gear contributions to overall airframe noise of commercial aircraft during landing configurations. Data measurement and analysis consist of mean and fluctuating model surface pressure, noise source localization maps using a large-aperture microphone directional array, and the determination of far field noise level spectra using a linear array of free field microphones. A total of 24 test runs are performed, consisting of four model assembly configurations, each of which is subjected to three test section speeds, in two different test section orientations. The different model assembly configurations vary in complexity from a fully-dressed to a partially-dressed geometry. The two model orientations provide flyover and sideline views from the perspective of a phased acoustic array for noise source localization via beamforming. Results show that the torque arm section of the model exhibits the highest rms pressures for all model configurations, which is also evidenced in the sideline view noise source maps for the partially-dressed model geometries. Analysis of acoustic spectra data from the linear array microphones shows a slight decrease in sound pressure levels at mid to high frequencies for the partially-dressed cavity open model configuration. In addition, far field sound pressure level spectra scale approximately with the 6th power of velocity and do not exhibit traditional Strouhal number scaling behavior.

Khorrami, Mehdi R.↗
NASA NTRS2016

Effects of Different Heave Motion Components on Pilot Pitch Control Behavior

The study described in this paper had two objectives. The first objective was to investigate if a different weighting of heave motion components decomposed at the center of gravity, allowing for a higher fidelity of individual components, would result in pilot manual pitch control behavior and performance closer to that observed with full aircraft motion. The second objective was to investigate if decomposing the heave components at the aircraft's instantaneous center of rotation rather than at the center of gravity could result in additional improvements in heave motion fidelity. Twenty-one general aviation pilots performed a pitch attitude control task in an experiment conducted on the Vertical Motion Simulator at NASA Ames under different hexapod motion conditions. The large motion capability of the Vertical Motion Simulator also allowed for a full aircraft motion condition, which served as a baseline. The controlled dynamics were of a transport category aircraft trimmed close to the stall point. When the ratio of center of gravity pitch heave to center of gravity heave increased in the hexapod motion conditions, pilot manual control behavior and performance became increasingly more similar to what is observed with full aircraft motion. Pilot visual and motion gains significantly increased, while the visual lead time constant decreased. The pilot visual and motion time delays remained approximately constant and decreased, respectively. The neuromuscular damping and frequency both decreased, with their values more similar to what is observed with real aircraft motion when there was an equal weighting of the heave of the center of gravity and heave due to rotations about the center of gravity. In terms of open- loop performance, the disturbance and target crossover frequency increased and decreased, respectively, and their corresponding phase margins remained constant and increased, respectively. The decomposition point of the heave components only had limited effects on pilot manual control behavior and performance.

manual control↗
DOE OSTI2019

Validation of Numerical Models of the Offshore Wind Turbine from the Alpha Ventus Wind Farm Against Full-Scale Measurements Within OC5 Phase III: Preprint

The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project, is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project validates OWT models against the measurements recorded on Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. The following operating conditions of the wind turbine were chosen for the validation: (1) Idling below the cut-in wind speed; (2) Rotornacelle assembly (RNA) rotation maneuver below the cut-in wind speed; (3) Power production below and above the rated wind speed; and (4) Shut-down. A number of validation load cases were defined based on these operating conditions. The following measurements were used for validation: (1) Strains and accelerations recorded on the support structure; (2) Pitch, yaw, and azimuth angles, generator speed, and electrical power recorded from the RNA. Strains were not directly available from the majority of the OWT simulation tools. Therefore, strains were calculated based on out-of-plane bending moments, axial forces, and geometrical properties of the structural members. Also, a number of issues arose during the validation: (1) The need for a thorough quality check of sensor measurements; (2) The sensitivity of the turbine loads to the controller and airfoil properties, which were only approximated in the modeling approach; (3) The importance of estimating and applying an appropriate damping value for the structure; and (4) The importance of wind characteristics beyond turbulence on the loads. The simulation results and measurements were compared in terms of time series, discrete Fourier transforms (DFTs), power spectral densities (PSDs), probability density functions (PDFs) of strains and accelerometers. A good match was achieved between the measurements and models set up by OC5 Phase III participants.

17 WIND ENERGY↗
DOE OSTI2019

Validation of Numerical Models of the Offshore Wind Turbine From the Alpha Ventus Wind Farm Against Full-Scale Measurements Within OC5 Phase III

The main objective of the Offshore Code Comparison Collaboration Continuation, with Correlation (OC5) project is validation of aero-hydro-servo-elastic simulation tools for offshore wind turbines (OWTs) through comparison of simulated results to the response data of physical systems. Phase III of the OC5 project validates OWT models against the measurements recorded on a Senvion 5M wind turbine supported by the OWEC Quattropod from the alpha ventus offshore wind farm. The following operating conditions of the wind turbine were chosen for the validation: (1) Idling below the cut-in wind speed; (2) Rotor-nacelle assembly (RNA) rotation maneuver below the cut-in wind speed; (3) Power production below and above the rated wind speed; and (4) Shutdown. A number of validation load cases were defined based on these operating conditions. The following measurements were used for validation: (1) Strains and accelerations recorded on the support structure; (2) Pitch, yaw, and azimuth angles, generator speed, and electrical power recorded from the RNA. Strains were not directly available from the majority of the OWT simulation tools. Therefore, strains were calculated based on out-of-plane bending moments, axial forces, and cross-sectional properties of the structural members. Also, a number of issues arose during the validation: (1) The need for a thorough quality check of sensor measurements; (2) The sensitivity of the turbine loads to the controller and airfoil properties, which were only approximated in the modeling approach; (3) The importance of estimating and applying an appropriate damping value for the structure; and (4) The importance of wind characteristics beyond turbulence on the loads. The simulation results and measurements were compared in terms of time series, discrete Fourier transforms, power spectral densities, probability density functions of strains and accelerometers. A good match was achieved between the measurements and models set up by OC5 Phase III participants.

17 WIND ENERGY↗
DOE OSTI2019

Clustering in structure and reactions using configuration interaction techniques

Atomic nuclei are remarkable quantum many-body systems where clustering properties develop naturally from underlying interactions between the constituent nucleons. Clustering degrees of freedom manifest themselves in multiple structure and reaction observables. Our goal is to study nuclear clustering and its emergence in many-nucleon dynamics from nucleon-nucleon interactions. Clustering is a phenomenon that is known to emerge on the boundary between structure and reactions, therefore developing appropriate techniques that bridge the structure-reaction divide and establishing connections to observables is among our principal objectives. Showing consistency and how the new techniques can be reduced to well established other methods is an important part of this work. Here, the configuration-interaction technique based on second quantization is used to treat the quantum many-body problem assuring that fermionic antisymmetry is fully satisfied. The use of the harmonic oscillator single-particle basis allows for the center-of-mass coordinate to be separated and prepared in a desired oscillator state for each cluster. The relative motion reaction basis channels are constructed by coupling clusters in different harmonic oscillator states with respect to their relative motion. Finally, using a resonating group method strategy we solve the generalized eigenvalue problem to obtain scattering channels. Structural clustering characteristics are discussed and the modified harmonic oscillator representation for scattering equations method is used to extract scattering observables. New methods for treating clustering problems have been put forward. We demonstrate broad applicability of the developed techniques. Examples highlight connections with algebraic techniques, and the role of approximations leading to algebraic limits is assessed using realistic examples. Various types of clustering characteristics are used to study alpha clustering in light nuclei that are relevant to currently ongoing experimental efforts. We demonstrate the emergence of strongly clustered bands of states in beryllium, triple alpha channels in 12 C, and molecular type clustering in 21 Ne. Starting from nucleon-nucleon interactions without any additional assumptions scattering phase shifts for alpha-alpha scattering are determined and shown to be consistent with those observed. In this work we put forward a new configuration-interaction-based method that targets the physics of clustering, and further unifies nuclear structure and reactions. We provide detailed discussions and many examples highlighting features and advantages of the approach.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2017

Bench Scale Process for Low Cost CO 2 Capture Using a PhaseChanging Absorbent: Techno-Economic Analysis Topical Report

The objective of this project is to design and build a bench-scale process for a novel phase-changing CO 2 capture solvent. The project will establish scalability and technical and economic feasibility of using a phase-changing CO 2 capture absorbent for post-combustion capture of CO 2 from coal-fired power plants with 90% capture efficiency and 95% CO 2 purity at a cost of $40/tonne of CO 2 captured by 2025 and a cost of <$10/tonne of CO 2 captured by 2035. This report presents system and economic analysis for a process that uses a phase changing aminosilicone solvent to remove CO 2 from pulverized coal (PC) power plant flue gas. The aminosilicone solvent is a pure 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (GAP-0). Performance of the phase-changing aminosilicone technology is compared to that of a conventional carbon capture system using aqueous monoethanolamine (MEA). This analysis demonstrates that the aminosilicone process has significant advantages relative to an MEA-based system. The first-year CO 2 removal cost for the phase-changing CO 2 capture process is $52.1/tonne, compared to $66.4/tonne for the aqueous amine process. The phase-changing CO 2 capture process is less costly than MEA because of advantageous solvent properties that include higher working capacity, lower corrosivity, lower vapor pressure, and lower heat capacity. The phase-changing aminosilicone process has approximately 32% lower equipment capital cost compared to that of the aqueous amine process. However, this solvent is susceptible to thermal degradation at CSTR desorber operating temperatures, which could add as much as $88/tonne to the CO 2 capture cost associated with solvent makeup. Future work is focused on mitigating this critical risk by developing an advanced low-temperature desorber that can deliver comparable desorption performance and significantly reduced thermal degradation rate.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1993

Mapping the stability region of the 3:2 Neptune-Pluto resonance

Pluto and Charon are most likely the remnants of a large number of objects that existed in the Uranus-Neptune region at early epochs of the solar system. Numerical integrations have shown that, in general, such objects were ejected from the planetary region on timescales of approximately 10(exp 7) years after Neptune and Uranus reached their current masses. It is thought that the Pluto-Charon system survived to current times without being dynamically removed in this way because it is trapped in a set of secular and mean motion resonances with Neptune. The best-known Pluto-Neptune orbit coupling is the 3:2 mean motion resonance discovered almost 30 years ago by C. Cohen and E. Hubbard. These workers showed that the resonance angle, delta is equivalent to 3(lambda(sub P)) - 2(lambda(sub N)) - omega-bar(sub P) where omega-bar(sub P) is the longitude of perihelion of the Pluto-Charon system, and lambda(sub N) and lambda(sub P) are the mean longitude of Neptune and Pluto-Charon respectively, librates about 180 deg with an amplitude, A(sub delta), of 76 deg. A numerical simulation project to map out the stability region of the 3:2 resonance is reported. The results of these simulations are important to understanding whether Pluto's long-term heliocentric stability requires only the 3:2 resonance, or whether it instead requires one or more of the other Pluto-Neptune resonances. Our study also has another important application. By investigating stability timescales as a function of orbital elements, we gain insight into the fraction of orbital phase space which the stable 3:2 resonance occupies. This fraction is directly related to the probability that the Pluto-Charon system (and possibly other small bodies) could have been captured into this resonance.

Levison, H. F.↗
NASA NTRS1992

Life sciences recruitment objectives

The goals of the Life Sciences Division of the Office of Space Sciences and Application are to ensure the health, well being and productivity of humans in space and to acquire fundamental scientific knowledge in space life sciences. With these goals in mind Space Station Freedom represents substantial opportunities and significant challenges to the Life Sciences Division. For the first time it will be possible to replicate experimental data from a variety of simultaneously exposed species with appropriate controls and real-time analytical capabilities over extended periods of time. At the same time, a system for monitoring and ameliorating the physiological adaptations that occur in humans subjected to extended space flight must be evolved to provide the continuing operational support to the SSF crew. To meet its goals, and take advantage of the opportunities and overcome the challenges presented by Space Station Freedom, the Life Sciences Division is developing a suite of discipline-focused sequence. The research phase of the Life Sciences Space Station Freedom Program will commence with the utilization flights following the deployment of the U.S. laboratory module and achievement of Man Tended Capability. Investigators that want the Life Sciences Division to sponsor their experiment on SSF can do so in one of three ways: submitting a proposal in response to a NASA Research Announcement (NRA), submitting a proposal in response to an Announcement of Opportunity (AO), or submitting an unsolicited proposal. The scientific merit of all proposals will be evaluated by peer review panels. Proposals will also be evaluated based on relevance to NASA's missions and on the results of an Engineering and Cost Analyses. The Life Sciences Division expects that the majority of its funding opportunities will be announced through NRA's. It is anticipated that the first NRA will be released approximately three years before first element launch (currently scheduled for late 1995). Subsequent NRA's will be released on a rotating two year cycle.

Keefe, J. Richard↗
NASA NTRS1999

Growth of Compound Semiconductors in a Low Gravity Environment: Microgravity Growth of PbSnTe

The growth of the alloy compound semiconductor lead tin telluride (PbSnTe) was chosen for a microgravity flight experiment in the Advanced Automated Directional Solidification Furnace (AADSF), on the United States Microgravity Payload-3 (USNP-3) in February, 1996 and on USNW- 4 in November, 1997. The objective of these experiments was to determine the effect of the reduction in convection, during the growth process, brought about by the microgravity environment. The properties of devices made from PbSnTe, an alloy of PbTe and SnTe, are dependent on the ratio of the elemental components in the starting crystal. Compositional uniformity in the crystal is only obtained if there is no significant mixing in the liquid during growth. The technological importance of PbSnTe lies in its band gap versus composition diagram which has a zero energy crossing at approximately 40% SnTe. This facilitates the construction of long wavelength (greater than 6 gm) infrared detectors and lasers. The properties and utilization of PbSnTe are the subject of other papers. 1,2 PbSnTe is also interesting from a purely scientific point of view. It is, potentially, both solutally and thermally unstable due to the temperature and density gradients present during growth. Density gradients, through thermal expansion, are imposed in directional solidification because temperature gradients are required to extract heat. Solutal gradients occur in directional solidification of alloys due to segregation at the interface. Usually the gradients vary with both experiment design and inherent materials properties. In a simplified one dimensional analysis with the growth axis parallel to the gravity vector, only one of the two instabilities work at a time. During growth, the temperature in the liquid increases ahead of the interface. Therefore the density, due to thermal expansion, is decreasing in that direction. However, the phase diagram shows that the lighter SnTe is preferentially rejected at the interface. This causes the liquid density to increase with distance away from the interface.

Fripp, A. L.↗
NASA NTRS2002

Ion Storage Tests with the High Performance Antimatter Trap (HiPAT)

The NASA/Marshall Space Flight Centers (NASA/MSFC) Propulsion Research Center (PRC) is evaluating an antiproton storage system, referred to as the High Performance Antiproton Trap (HiPAT). This interest stems from the sheer energy represented by matter/antimatter annihilation process with has an energy density approximately 10 order of magnitude above that of chemical propellants. In other terms, one gram of antiprotons contains the equivalent energy of approximately 23 space shuttle external tanks or ET's (each ET contains roughly 740,000 kgs of fuel and oxidizer). This incredible source of stored energy, if harnessed, would be an enabling technology for deep space mission where both spacecraft weight and propulsion performance are key to satisfying aggressive mission requirements. The HiPAT hardware consists of a 4 Tesla superconductor system, an ultra high vacuum test section (vacuum approaching 10(exp -12) torr), and a high voltage confinement electrode system (up to 20 kvolts operation). The current laboratory layout is illustrated. The HiPAT designed objectives included storage of up to 1 trillion antiprotons with corresponding lifetimes approaching 18 days. To date, testing has centered on the storage of positive hydrogen ions produced in situ by a stream of high-energy electrons that passes through the trapping region. However, due to space charge issues and electron beam compression as it passes through the HiPAT central field, current ion production is limited to less then 50,000 ions. Ion lifetime was determined by counting particle populations at the end of various storage time intervals. Particle detection was accomplished by destructively expelling the ions against a micro-channel plate located just outside the traps magnetic field. The effect of radio frequency (RF) stabilization on the lifetime of trapped particles was also examined. This technique, referred to as a rotating wall, made use of a segmented electrode located near the center of the trap on which various phases of a particular frequency were applied. Various experiments were performed illustrating the ability of an RF drive to both prolong and reduced the lifetimes of various ion species depending on the selected frequency. HiPAT is now being reconfigured for testing with an ion source that will provide both positive and negative hydrogen ions from an external source. This ion system shall provide higher fill capacity (order of million of ions per shot), stacking of multiple shots, and injection schemes typical of a realistic antiproton delivery system.

Martin, James J.↗
NASA NTRS1994

Detection of CO Cameron band emission in comet P/Hartley 2 (1991 XV) with the Hubble Space Telescope

Ultraviolet (UV) spectra of comet P/Hartley 2 (1991 XV) taken with the Faint Object Spectrograph (FOS) on the Hubble Space Telescope (HST) in 1991 September reveal several bands of the Cameron system of CO (a 3 Pi-X 1 Sigma). These band are most likely due to 'prompt' emission from CO2 and, thus, provide a direct tracer of the CO2 abundance in the nucleus. Photodissociative excitation of CO2 is probably the largest contributor to the Cameron band emission, but significant contributions from electron impact excitation of CO, electron impact dissociation of CO2, and dissociative recombination of CO2(+), are also possible. Using our estimate that photodissociative excitation is responsible for approximately 60% of the total excitation of the Cameron system, we derive Q(sub CO2) approximately 2.6 x 10(exp 27) molecules/s, which implies CO2/H20 approximately 4%. If all of the Cameron band emission is due to photodissociative excitation, then CO2/H2O = 7 +/- 2%. For the largest possible contributions from the other excitation mechanisms considered, the CO2 abundance could be as a small as aproximately 2-3%. We did not detect CO Fourth Positive Group emission in our data and derive an upper limit of CO/H2O less than or equal to 1% (3 sigma) for CO coming directly from the nucleus. Comparison of the relative CO2 and CO abundances in P/Hartley 2 to those in P/Halley (CO2/H2O approximately 3%-4%, CO/H20 approximately 4% for the nucleus source) indicates that selective devolatilization of the nucleus may have occurred for P/Hartley 2. A relatively large CO2/CO ratio (i.e., approximately greater than 1) seems to be a common property of cometary nuclei. Since gas phase chemistry, in either the solar nebula or the interstellar medium (ISM), appears incapable of producing large relative CO2 abundances, the CO2 in cometary nuclei is probably produced either by UV and/or cosmic ray irradiation of ISM grains prior to the formation of the Solar System, or by condensation fractionation in the solar nebula.

Weaver, H. A.↗
NASA NTRS2024

Test and Analysis of the 8-foot Diameter Cylindrical Sandwich Composite Test Article CTA8.2B: As part of the NASA Engineering and Safety Center Shell Buckling Knockdown Factor Project

The buckling response of thin-walled cylindrical structures have long been shown to be sensitive to various imperfections. That is, imperfections related to load introduction, boundary conditions, material property variation, and geometric deviations can all contribute to experimentally obtained buckling loads being lower than the buckling loads predicted for perfect representations of the same thin-walled cylindrical structure. To account for the influence of geometry-based imperfections of a thin-walled cylindrical structure on buckling response, a design factor (also known as a buckling knockdown factor) is used during the design phase. Guidelines for buckling knockdown factors are readily available in NASA SP-8007, Buckling of Thin Walled Circular Cylinders, which was updated in 2020. Prior to this recent update, NASA SP-8007 had not been updated since 1969, and since that time, computational analysis, experimental testing, and manufacturing methods have significantly improved. The NASA Engineering and Safety Center (NESC) Shell Buckling Knockdown Factor Project (SBKF, NESC Assessment 07-010-E) had the goal of developing buckling design recommendations for select classes of metallic and composite launch-vehicle structures [3]. Specifically, the test and analysis results from the fourth SBKF composite test article SBKF-P3-CYL-CTA8.2B, which is referred to as CTA8.2B, are described in this paper. This test was the fourth in a series of four tests on sandwich composite cylinders that will be used to experimentally validate analysis methods, which in turn can be used to develop new analysis-based shell buckling design guidelines for typical sandwich composite launch vehicle cylindrical structures. Publications describing previous test validation with analysis are available in Refs. CTA8.2B was designed to occupy one corner of the design space with approximately equal bending stiffnesses in the axial and transverse directions and have a larger ratio of radius to effective shell thickness. Each test article had a unique design and was designed to occupy a specific region of the design space. CTA8.2B was an 8-foot diameter honeycomb-core sandwich cylinder that was fabricated and tested at the NASA Marshall Space Flight Center (MSFC). The primary objectives of this test were to interrogate the structural capability of a composite test article, and to verify the test article design and analysis approach for cylinders subjected to axial compression and combined axial and bending loads. First, descriptions of the test article design and test are given in Section 2.0, and modeling and analysis methods used in support of the test article design and testing activities are described briefly in Section 3.0. Then, select test results are presented and compared to predicted results in Section 4.0, and concluding remarks are presented in Section 5.0. Finally, drawings of CTA8.2B and references used to support the test and analysis are provided in the Appendix.

Nonlinear analysis↗
NASA NTRS2006

A Lunar Communications and Navigation Satellite Concept for the Robotic Lunar Exploration Program

The Second Robotic Lunar Exploration Program (RLEP) mission has two primary objectives. Broadly stated, they are "To See the Light" and "To Touch the Ice", meaning one mission objective is to survey the lighting conditions on the rim of a candidate crater over the course of a year, and the second objective is to descend into th.! s crater to search for water ice. The Space Communications Program Office at NASA/GSFC is supporting the RLEP-2 Project by developing a communications and navigation architecture for the mission. The primary candidate crater studied is the Shackleton Crater near the South Pole of the Moon. The rim of this crater has approximately 14 contiguous days of visibility to the Earth over the course of a month, while mission elements in the crater have no line of sight to either the Earth or potentially an element on the rim of the crater. One solution studied is to launch a relay spacecraft with RLEP-2 to provide communications and navigation services to the elements on the lunar surface. To support operations concepts requiring long duration contacts between the relay and the elements in the crater, an inclined elliptical orbit originally conceived by Todd Ely a t JPL was chosen for the relay. The orbit was adjusted to lower the maximum range while maintaining its "frozen" nature, meaning once placed in this orbit little delta-V is required for orbit maintenance. The orbital parameters were adjusted such that the relay has visibility into the crater for approximately 8.7 hours of the 12 hour orbital period. The relay satellite design draws heavily upon heritage concepts and hardware to achieve a very low risk implementation. The design concept is a 3-axis spacecraft that is capable of supporting return communication links from multiple surface elements concurrently through a four-element S-Band Multiple Access phased array with two forward links provided through single dedicated elements. The payload is a bent-pipe relay with beamforming performed on the ground (Earth). To mitigate concerns with multipath observed during Mars missions, the preliminary design employs PN-spread signal structures which have been used successfully by Tracking and Data Relay Satellite System (TDRSS) users for simultaneous real-time and recorded data playback. Details of the relay communication trade studies and rationale for the selected design elements are discussed in the paper.

Gramling, Jeffrey J.↗
DOE OSTI2023

Multi-Sourced Collaboration for the Production and Refining of Rare Elements and Critical Metals (Final Technical Report)

The project objective was to develop a feasible and cost-effective method for recovering rare earth elements (REEs) and critical materials (CMs) from coal and coal byproducts, resulting in high-purity individually separated REEs and CMs. The targeted REEs included Y, Pr, Nd, Gd, Dy, and Sm, with a purity of over 99.5%, while the CMs included Co, Mn, Ga, Sr, Li, Ni, Zn, and Ge, with a purity of over 90%. The project aimed to design a prototype facility capable of producing 1-3 tonnes/day of high-purity REO mixes. The work was divided into four designated circuits: 1) REE extraction and concentration, 2) REE separation and purification, 3) RE metal production, and 4) CM production. To achieve these goals, the project involved 11 tasks, including technology reviews, research, process flow diagram development, mass balance estimation, and preliminary technical-economic analysis. The project team included researchers from the University of Kentucky, University of Alabama and Virginia Tech as well as process specialists from Argonne National Laboratory. MP Materials provided technical support regarding rare earth markets and processing while Alliance Coal performed resource assessment. The project included a market analysis for Nd/Pr, Tb, Dy, Gd, Y, Co, Mn, Li, Sr, Ga, Ni, Zn, and Ge. These analyses provided insights into the supply and demand trends as well as historic and future projections of market price relative to purity requirements for these elements. Two coal resources were selected for the project: the West Kentucky No. 13 (Baker) Seam and an undisclosed lignite resource in the Illinois coal basin. The estimated quantities of REEs in these resources were calculated based on production samples and drilling data. It was estimated that there is adequate supply for an operation producing one metric ton daily of higher purity mixed rare earth oxides (MREO) for approximately 20 years at a site located in western Kentucky. In Circuit 1, project data was obtained from a pilot heap leach and REE concentration facility. It was concluded that the existing circuit, which generated a MREO concentrate, two types of CM mixed products, and Li- and Sr-containing waters, would be suitable feed for circuits 2-4. Data from the first-of-its-kind coal coarse refuse heap leach pilot pad played a crucial role in estimating reliable elemental concentrations of the pregnant leaching solution (PLS). The average total REE concentration in the PLS was found to be 28.6 ppm. In Circuit 2, several concepts were explored including a novel process referred to as solvent-assisted chromatography (SAC). This concept involved a novel columnar reactor that incorporated multiple mixer/settlers, thereby enabling the operation of counter-flowing aqueous and organic phases. Unfortunately, due to project time constraints, a complete fundamental modeling analysis could not be completed to fully evaluate the technology. Molten salt electrowinning was considered as an alternative for circuit 3 following circuit 2 purification circuit utilizing the novel SAC process. A mass and energy balance of Nd reduction to metal in a fluoride containing molten salt electrolyte was conducted. Comparisons were made with the current state of Asian molten salt electrorefining, and potential improvements in siphoning rare earth metals (REM) from the reactor were presented. A cost estimate was performed for the production of 1 tonne per day, which yielded a total of $2.29 million for the nine electrowinning (EW) cells required. The selected option for circuits 2 and 3 was a plasma distillation process, which initially separates rare earth elements (REEs) from other elements. This is followed by selective electrowinning in various ionic liquids. The selection was made on the basis of thermodynamic modeling and experimental data previously published by a project partner. The combination offers an innovative approach to integrated refining and RE metal production. For Circuit 4, an extensive literature review was conducted for the processing of the CMs. The ultimate decision was to utilize a combined plasma and ionic liquid process as well to produce individual high-purity concentrates of Zn, Ni, Co, Mn, and Mg. A separate flowsheet for Li and Sr was recommended, which would yield carbonates of these elements. Due to the lack of suitable experimental data at this time, a process recommendation could not be provided but several methods have been proposed for consideration. Lastly, a techno-economic analysis (TEA) was conducted to assess the effectiveness of the proposed process for further investigation. The TEA results revealed a capital expense (CapEx) of $737 million and an annual operational expense (OpEx) of $220 million. Due to the selected elements, the hypothetical heap leach pad can produce 1 metric tonne per day of REO equivalent, but a conscious decision was made to only treat targeted REEs, resulting in the production of 0.4 metric tonne of REM. An estimated annual revenue of $90.87 million was projected based on standard market pricing information provided by the funding agency. During the TEA, ten different modules were evaluated for costing purposes. The precipitation circuit was identified as the largest single operational expense, followed by the Mg/Mn process due to the amount of treated metal. In terms of capital expenditures, the heap leach process incurred the highest cost, followed by the Mg/Mn process. The scalability of the plasma process is a crucial consideration since the reactors cannot be scaled beyond the largest demonstrated size due to their reliance on surface area of the slag and vapor phase. The purity estimate for the REEs are generally 98%±2% to produce a metal. The purity level being lower than the project objective was due to the lack of specific experimental data needed to tighten the tolerance of the estimates. Based on literature and previous experience, the CMs are estimated as follows; Ga (95%+, metal), Sr (95%+, carbonate), Li (95%+, carbonate), Ni (98%±2%, metal), Zn (95%+, metal sponge), Ge (95%+, metal), Co (98%±2%, metal), and Mn (98%±2%, metal).

01 COAL, LIGNITE, AND PEAT↗