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At least 199 records · Page 11

All sources NASA NTRS DOE OSTI

NASA NTRS2007

Inadvertent Earth Reentry Breakup Analysis for the New Horizons Mission

The New Horizons (NH) spacecraft was launched in January 2006 aboard an Atlas V launch vehicle, in a mission to explore Pluto, its moons, and other bodies in the Kuiper Belt. The NH spacecraft is powered by a Radioisotope Thermoelectric Generator (RTG) which encases multiple General Purpose Heat Source (GPHS) modules. Thus, a pre-launch vehicle breakup analysis for an inadvertent atmospheric reentry in the event of a launch failure was required to assess aerospace nuclear safety and for launch contingency planning. This paper addresses potential accidental Earth reentries analyzed at the Jet Propulsion Laboratory (JPL) which may arise during the ascent to parking orbit, resulting in a suborbital reentry, as well as a departure from parking orbit, resulting in an orbital reentry.

Ling, Lisa M.↗

NASA NTRS2016

Conceptual Drivers for an Exploration Medical System

Interplanetary spaceflight, such as NASA's proposed three-year mission to Mars, provides unique and novel challenges when compared with human spaceflight to date. Extended distance and multi-year missions introduce new elements of operational complexity and additional risk. These elements include: inability to resupply medications and consumables, inability to evacuate injured or ill crew, uncharted psychosocial conditions, and communication delays that create a requirement for some level of autonomous medical capability. Because of these unique challenges, the approaches used in prior programs have limited application to a Mars mission. On a Mars mission, resource limitations will significantly constrain available medical capabilities, and require a paradigm shift in the approach to medical system design and risk mitigation for crew health. To respond to this need for a new paradigm, the Exploration Medical Capability (ExMC) Element is assessing each Mars mission phase-transit, surface stay, rendezvous, extravehicular activity, and return-to identify and prioritize medical needs for the journey beyond low Earth orbit (LEO). ExMC is addressing both planned medical operations, and unplanned contingency medical operations that meld clinical needs and research needs into a single system. This assessment is being used to derive a gap analysis and studies to support meaningful medical capabilities trades. These trades, in turn, allow the exploration medical system design to proceed from both a mission centric and ethics-based approach, and to manage the risks associated with the medical limitations inherent in an exploration class mission. This paper outlines the conceptual drivers used to derive medical system and vehicle needs from an integrated vision of how medical care will be provided within this paradigm. Keywords: (Max 6 keywords: exploration, medicine, spaceflight, Mars, research, NASA)

Antonsen, Erik↗

NASA NTRS2005

Flight Data Analysis of HyShot 2

The development of scramjet propulsion for alternative launch and payload delivery capabilities has comprised largely of ground experiments for the last 40 years. With the goal of validating the use of short duration ground test facilities, the University of Queensland, supported by a large international contingency, devised a ballistic re-entry vehicle experiment called HyShot to achieve supersonic combustion in flight above Mach 7.5. It consisted of a double wedge intake and two back-to-back constant area combustors; one supplied with hydrogen fuel at an equivalence ratio of 0.33 and the other un-fueled. Following a first launch failure on October 30th 2001, the University of Queensland conducted a successful second launch on July 30th, 2002. Post-flight data analysis of the second launch confirmed the presence of supersonic combustion during the approximately 3 second test window at altitudes between 35 and 29 km. Reasonable correlation between flight and some pre-flight shock tunnel tests was observed.

Hass, Neal E.↗

NASA NTRSDate not supplied

Optimizing Consumable Gas Tank Usage while Maintaining Emergency Reserves Between Two Pressure Control Systems on Gateway

Two of NASA’s Lunar Space Station (Gateway) modules, the Habitation and Logistics Outpost (HALO) and International Habitat (IHAB) contain a pressure control system (PCS) that is used to supply Nitrogen (N2) and Oxygen (O2) to maintain a habitable environment within Gateway, with only one of the PCS active at any given time. To protect the crew during a contingency that is affecting pressure control and therefore gas consumables, Gateway is required to have sufficient amount of reserve consumable gas across the entire habitable Gateway stack of modules until the gas can be replenished by crew changing out a gas tank. This will occur in a non-contingency setting either on the current mission or on the next mission. To access the stack reserve Gateway features a Nitrogen Oxygen Transfer System (NOTS) between HALO and IHAB that allows each module’s PCS to access the gas tanks in the other module. The PCS designs are different between the two modules and lack interchangeable tanks so which module has active PCS must be accounted for in logistics planning. This paper describes the logistics resupply planning analysis used to determine the most efficient use of the tanks within each PCS, and a method for switching which module is active for PCS while maintaining the stack reserve that preserves enough gas to cover contingency cases.

Rachel Anne Sturtz↗

DOE OSTI2025

Derivation of A Representative Elementary Volume (REV) for Upscaled Two-Phase Flow in Porous Media

Relative permeability plays an important role in the upscaling of multiphase flow in porous media from the pore scale to the Darcy scale. The entire concept of relative permeability is contingent on the existence of a representative elementary volume (REV). As we move to smaller samples to measure relative permeability, such as with digital core analysis, the concept of a classical REV has become increasingly unlikely when using the conventional approach to defining a representative volume. The “‘conventional”’ understanding of an REV is that a large enough volume must be considered such that spatial variability averages out. In digital rock methods, such as pore-scale simulations based on micro-computed tomography (CT) images, the domain size is typically 2 to 4 mm. This is approximately the length scale of a single-phase flow REV using the classic REV approach. However, the single-phase perspective does not consider the complex dynamics and fluctuations often observed in multiphase flow systems, even at centimeter-scale experiments and/or simulations. A fundamental question is, therefore, whether the domain size commonly used in digital rock simulations can provide a consistent energy budget such that the concept of relative permeability exists. Based on first principles, relative permeability accounts for the rate of energy dissipated in a stationary process. If the dynamics are fluctuating, the energy dissipated can vary but will average out over a long enough timescale. The key to determining the validity of the relative permeability is the timescale of the measurement, not the spatial scale. The conventional REV theory assumes that spatial, temporal, and ensemble averages are equivalent in an ergodic system, but it does not provide a way to test this assumption. We provide a formal way to identify the timescale where the relative permeability accurately captures energy dissipation as a way to validate relative permeability measurements and quantitatively assess their accuracy. This result will be tested for a practical SCAL test, determining how long a flow experiment needs to be run to accurately characterize the rate of energy dissipation by the flow. The outcome will be a best practice guide for the determination of relative permeability from core-scale experiments and/or digital core simulations that ensure the energy budget is fully accounted for in the relative permeability coefficient.

Mcclure, James [Virginia Tech, Blacksburg]↗

DOE OSTI2023

Grid Strength Analysis for Integrating 30 GW of Offshore Wind Generation by 2030 in the U.S. Eastern Interconnection

Offshore wind is a key player in the transition to a decarbonized electric gird, and the United States has set ambitious goals of integrating 30 GW of offshore wind capacity by 2030 and 110 GW by 2050. To facilitate this integration, the National Renewable Energy Laboratory and the Pacific Northwest National Laboratory are conducting the Atlantic Offshore Wind Transmission Study to assess transmission solutions. To achieve the 110-GW target by 2050, meticulous planning for network expansion and resource allocation is essential; however, meeting the 2030 goals requires integrating offshore wind power with minimal system upgrades, thus necessitating a careful study of grid strength and stability. The study team developed the Automated System-wide Strength Evaluation Tool (ASSET) to assess system strength under various operating conditions and contingencies, focusing on the proposed integration of 30 GW of offshore wind power by 2030. In this paper, we provide a summary of key features of the ASSET software and results of the grid strength analysis for integrating 30 GW of offshore wind generation by 2030 in the U.S. Eastern Interconnection.

Automated System-wide Strength Evaluation Tool (AS↗

DOE OSTI2023

Opportunities for wave energy in bulk power system operations

Wave energy resources have high, yet largely untapped potential as candidate generation technology. In this paper, we perform a data-driven analysis to characterize the impact of wave energy integration on bulk-scale power systems and market operations. Through data-driven sensitivity studies centered on an optimization-based production cost modeling formulation, our work characterizes the inflection point beyond which wave integration starts impacting power system operations, considering present day transmission infrastructure. Furthermore, our analysis also considers the joint effects of wave energy integration and system-wide transmission expansion. Finally, potential resilience scenarios such as wildfire-driven transmission contingencies and heat wave events are investigated, whereby the contributions of grid-integrated wave energy in alleviating the effects of the resilience events are analyzed. As our demonstration test bed, we consider a reduced-order network topology for the U.S. Western Interconnection with wave energy generation integrated at carefully selected sites across the coastal areas of Washington, Oregon, and northern California. Our results indicate that over a representative year of operations, wave energy integration systematically reduces locational marginal prices (LMPs) of energy and price volatility, especially during periods of high wave resource availability (winter months for the U.S. west coast). Average, maximum, and minimum of hourly LMPs over a typical year of operation was reduced by 2.95, 51.28, and 1.13 $\$$/MWh respectively (over a baseline scenario with no wave energy integration), when the selected network model had a total of 5000 MW wave power installed capacity during the representative year of study. The effects of wave energy integration can remain localized with existing transmission infrastructure (identified to be most pronounced in the Pacific Northwest region in the example we studied). However, with concurrent transmission expansion, the impacts of wave energy integration are likely to have a higher geographical spread. Our results also indicate that wave energy may be able to assist power system operations during resilience events such as major transmission contingencies and heat wave events, although such benefits might be dependent on factors such as proximity of affected area to wave resources, availability of adequate resource potential and adequate transmission capacity.

16 TIDAL AND WAVE POWER↗

NASA NTRS2016

Conceptual Drivers for an Exploration Medical System

Interplanetary spaceflight provides unique challenges that have not been encountered in prior spaceflight experience. Extended distance and timeframes introduce new challenges such as an inability to resupply medications and consumables, inability to evacuate injured or ill crew, and communication delays that introduce a requirement for some level of autonomous medical capability. Because of these challenges the approaches used in prior programs have limited application to a proposed three year Mars mission. This paper proposes a paradigm shift in the approach to medical risk mitigation for crew health and mission objectives threatened by inadequate medical capabilities in the setting of severely limited resources. A conceptual approach is outlined to derive medical system and vehicle needs from an integrated vision of how medical care will be provided within this new paradigm. Using NASA Design Reference Missions this process assesses each mission phase to deconstruct medical needs at any point during a mission. Two operational categories are proposed, nominal operations (pre-planned activities) and contingency operations (medical conditions requiring evaluation) that meld clinical needs and research needs into a single system. These definitions are used to derive a task level analysis to support quantifiable studies into a medical capabilities trade. This trade allows system design to proceed from both a mission centric and ethics-based approach to medical limitations in an exploration class mission.

Antonsen, E.↗

NASA NTRS2007

Space Shuttle MMOD Threat Mitigation Techniques

Prior to each shuttle mission, threat assessments are performed to determine the risk of critical penetration, payload bay door radiator tube leak and crew module window replacement from Micrometeoroid and Orbital Debris (MMOD). Mission parameters, such as vehicle attitude, exposure time and altitude are used as inputs for the analysis. Ballistic limit equations, based on hypervelocity impact testing of shuttle materials are used to estimate the critical particle diameters of the outer surfaces of the vehicle. The assessments are performed using the BUMPER computer code at the NASA/JSC Hypervelocity Impact Technology Facility (HITF). The most critical involves the calculation of Loss of Crew and Vehicle (LOCV) risk. In recent years, NASA has implemented several techniques to reduce the risk to the Shuttle from MMOD impacts. This paper will describe on-orbit inspection of the reinforced carbon-carbon (RCC) regions and the methods used discern hypervelocity impact damage. Impact damage contingency plans and on-orbit repair techniques will also be discussed. The wing leading edge impact detection system (WLEIDS) and it's role in the reduction of on-orbit risk reduction will be presented. Finally, an analysis of the effectivity of alternative shuttle flight attitudes on MMOD risk will be demonstrated.

Hyde, Justin L.↗

DOE OSTI2024

Unveiling Morphology and Crystallinity Dynamics in Ni x Mn 1– x CO 3 Cathode Precursors through Batch-Mode Coprecipitation

This study delves into the synthesis and control of Ni x Mn 1–x CO 3 , a critical class of Mn-rich, Co-free precursors vital for cathode-oxide materials in energy storage and conversion technologies. Employing batch-mode coprecipitation, we systematically generated samples with varying Ni concentrations (x = 0, 0.1, 0.3, 0.5, 0.7, and 0.9) and conducted a comprehensive analysis of their compositions, crystallinities, transition-metal distributions, and particle morphologies through both experimental and computational methods. A significant variation in particle size and crystallinity was observed, contingent on the Ni content. Further, a pivotal transition emerged at Ni concentrations above x = ~0.5, transforming uniform morphologies, such as spherical, monodisperse, pseudo-single-crystalline particles, into bimodal, polycrystalline structures. Furthermore, the study highlights the role of Ni–ammonia complexes leading to Ni-deficient precipitates and underscores the importance of ammonia concentration in achieving precise Ni content control. This study unveils critical reaction conditions governing Mn-rich precursor properties that are vital for cathode-oxides, emphasizing the need for meticulous synthetic control and offering the potential for practical applications in advanced energy storage and conversion systems.

25 ENERGY STORAGE↗

NASA NTRS1981

Thermal investigation of nuclear waste disposal in space

A thermal analysis has been conducted to determine the allowable size and response of bare and shielded nuclear waste forms in both low earth orbit and at 0.85 astronomical units. Contingency conditions of re-entry with a 45 deg and 60 deg aeroshell are examined as well as re-entry of a spherical shielded waste form. A variety of shielded schemes were examined and the waste form thermal response for each determined. Two optimum configurations were selected. The thermal response of these two shielded waste configurations to indefinite exposure to ground conditions following controlled and uncontrolled re-entry is determined. In all cases the prime criterion is that waste containment must be maintained.

Wilkinson, C. L.↗

NASA NTRS1998

Lunar prospector mission design and trajectory support

The Lunar Prospector mission is the first dedicated NASA lunar mapping mission since the Apollo Orbiter program which was flown over 25 years ago. Competitively selected under the NASA Discovery Program, Lunar Prospector was launched on January 7, 1998 on the new Lockheed Martin Athena 2 launch vehicle. The mission design of Lunar Prospector is characterized by a direct minimum energy transfer trajectory to the moon with three scheduled orbit correction maneuvers to remove launch and cislunar injection errors prior to lunar insertion. At lunar encounter, a series of three lunar orbit insertion maneuvers and a small circularization burn were executed to achieve a 100 km altitude polar mapping orbit. This paper will present the design of the Lunar Prospector transfer, lunar insertion and mapping orbits, including maneuver and orbit determination strategies in the context of mission goals and constraints. Contingency plans for handling transfer orbit injection and lunar orbit insertion anomalies are also summarized. Actual flight operations results are discussed and compared to pre-launch support analysis.

Lozier, David↗

NASA NTRS2013

Thermal Performance Testing of EMU and CSAFE Liquid Cooling Gannents

Future exploration missions require the development of a new liquid cooling garment (LCG) to support the next generation extravehicular activity (EVA) suit system. The new LCG must offer greater system reliability, optimal thermal performance as required by mission directive, and meet other design requirements including improved tactile comfort. To advance the development of a future LCG, a thermal performance test was conducted to evaluate: (1) the comparable thermal performance of the EMU LCG and the CSAFE developed engineering evaluation unit (EEU) LCG, (2) the effect of the thermal comfort undergarment (TCU) on the EMU LCG tactile and thermal comfort, and (3) the performance of a torso or upper body only LCG shirt to evaluate a proposed auxiliary loop. To evaluate the thermal performance of each configuration, a metabolic test was conducted using the Demonstrator Spacesuit to create a relevant test environment. Three (3) male test subjects of similar height and weight walked on a treadmill at various speeds to produce three different metabolic loads - resting (300-600 BTU/hr), walking at a slow pace (1200 BTU/hr), and walking at a brisk pace (2200 BTU/hr). Each subject participated in five tests - two wearing the CSAFE full LCG, one wearing the EMU LCG without TCUs, one wearing the EMU LCG with TCUs, and one with the CSAFE shirt-only. During the test, performance data for the breathing air and cooling water systems and subject specific data was collected to define the thermal performance of the configurations. The test results show that the CSAFE EEU LCG and EMU LCG with TCU had comparable performance. The testing also showed that an auxiliary loop LCG, sized similarly to the shirt-only configuration, should provide adequate cooling for contingency scenarios. Finally, the testing showed that the TCU did not significantly hinder LCG heat transfer, and may prove to be acceptable for future suit use with additional analysis and testing.

Rhodes, Richard↗

NASA NTRS1979

Probabilistic analysis of air carrier accidents

In order to estimate the potential risks due to carbon fibers (CF) released from aircraft accidents, it was necessary to quantify the probability of an accident or incident at a major hub airport. This probability was contingent upon various conditions surrounding the incident including the phase of operation, aircraft type, and the weather conditions. The type of accident predicted was categorized according to its location relative to the runway and the severity of damage sustained. The methodology utilized to estimate the probability of a specific type of accident is outlined and the various models that were developed in the course of this work are described.

Source record↗

NASA NTRSDate not supplied

Effect of Carbon Dioxide Exposure on Physical and Cognitive Performance in A Simulated Spaceflight Contingency Scenario

INTRODUCTION: Carbon dioxide (CO2) produced by astronauts inside space suits can accumulate to levels that may affect health and performance. The human health and performance risks associated with different levels of CO2 exposure in the flight environment remain an area of debate. The purpose of this study is to characterize the limit of acceptable performance (cognitive and physical) decrements and symptom severity for mission operations when subjected to elevated inspired CO2 levels in simulated contingency lunar extravehicular activity (EVA) scenarios. METHODS: This study will create a simulation of a 1-hour, ~2km contingency EVA walk back to a habitat, incorporating a passive treadmill and a fully immersive virtual reality (VR) simulation of a lunar EVA environment. Subjects will be asked to walk on a treadmill while breathing partial pressures of CO2 of 0, 5, 10, 15, 20, 25, 30mmHg for 1 hour at a time. Cognitive performance will be quantified using validated cognitive tests and measures of functional task performance embedded within the VR environment. Test subject symptoms and self-assessment of performance will be evaluated via survey. RESULTS: This study currently has approval from NASA’s Institutional Review Board and has completed the Test Readiness Review process. Next steps for this research study include test subject recruitment, data collection, and analysis. Data collection is planned for calendar year 2023 and 2024. DISCUSSION: This study will provide valuable information regarding how various partial pressures of CO2 exposure impact acute health, as well as cognitive and physical performance during simulated contingency lunar EVA. This information will enable assessment of health and performance risk associated with spacesuit systems and operations concepts for future exploration missions as well as informing definition of future standards and requirements.

D. M. Nusbaum↗

NASA NTRSDate not supplied

Effect of Carbon Dioxide Exposure on Physical and Cognitive Performance in A Simulated Spaceflight Contingency Scenario

carbon dioxide↗

DOE OSTI2025

Leveraging public AI tools to explore systems biology resources in mathematical modeling

Predictive mathematical modeling is an essential part of systems biology and is interconnected with information management. Systems biology information is often stored in specialized formats to facilitate data storage and analysis. These formats are not designed for easy human readability and thus require specialized software to visualize and interpret results. Therefore, comprehending modeling and underlying networks and pathways is contingent on mastering systems biology tools, which is particularly challenging for users with no or little background in data science or system biology. To address this challenge, we investigated the usage of public Artificial Intelligence (AI) tools in exploring systems biology resources in mathematical modeling. We tested public AI’s understanding of mathematics in models, related systems biology data, and the complexity of model structures. Our approach can enhance the accessibility of systems biology for non-system biologists and help them understand systems biology without a deep learning curve.

59 BASIC BIOLOGICAL SCIENCES↗

NASA NTRS1972

Application of new radio tracking data types to critical spacecraft navigation problems

Earth-based radio tracking data types are considered, which involve simultaneous or nearly simultaneous spacecraft tracking from widely separated tracking stations. These data types are conventional tracking instrumentation analogs of the very long baseline interferometry (VLBI) of radio astronomy-hence the name quasi-VLBI. A preliminary analysis of quasi-VLBI is presented using simplified tracking data models. The results of accuracy analyses are presented for a representative mission, Viking 1975. The results indicate that, contingent on projected tracking system accuracy, quasi-VLBI can be expected to significantly improve navigation performance over that expected from conventional tracking data types.

Ondrasik, V. J.↗