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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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NASA NTRS2018

The Influence of Mental Workload in Causes of System Degradation in Air Traffic Control

System safety and resilience is a critical concern in the air traffic domain. An important element of maintaining system safety and resilience is the ability of systems to ‘degrade gracefully’. However, previous research on the causes of system degradation in the air traffic domain are sporadic, and the potential interaction between the causes of degradation, and the resulting possible compound effect on the entire system, has been under-researched. An interview study was conducted with 12 retired controllers as participants. The results of a thematic analysis revealed the key causes of system degradation, and the associated impact on the ability of the controllers to prevent system degradation or recover the system. Findings have direct implications for identifying and mitigating potential risks of increasingly automated air traffic control systems.

Edwards, Tamsyn E.↗
NASA NTRS2018

The Influence of Mental Workload in Causes of System Degradation in Air Traffic Control

System safety and resilience is a critical concern in the air traffic domain. An important element of maintaining system safety and resilience is the ability of systems to ‘degrade gracefully'. However, previous research on the causes of system degradation in the air traffic domain are sporadic, and the potential interaction between the causes of degradation, and the resulting possible compound effect on the entire system, has been under-researched. An interview study was conducted with 12 retired controllers as participants. The results of a thematic analysis revealed the key causes of system degradation, and the associated impact on the ability of the controllers to prevent system degradation or recover the system. Findings have direct implications for identifying and mitigating potential risks of increasingly automated air traffic control systems.

Edwards, Tamsyn↗
NASA NTRS2022

Near-Earth Object Surveyor Overview

The Near-Earth Object (NEO) Surveyor is designed to detect, categorize and characterize Near-Earth Objects (NEOs) using infrared imaging. The project was approved to enter the preliminary design phase (Phase B) in FY21 after an extended Concept Development Phase (Phase A). The NEO Surveyor project responds to US Public Law 109-155[1], National Research Council’s report “Defending Planet Earth: Near-Earth Object Surveys & Hazard Mitigation Strategies (2010)”[2], the U. S. National Near-Earth Object Preparedness Strategy and Action Plan (June 2018)[3], and the objectives of NASA’s Planetary Defense Coordination Office (PDCO). The goals of the NEO Surveyor project are to: (1) identify impact hazards to the Earth posed by NEOs (defined as asteroids and comets that come within 1.3 AU of the Sun) by performing a comprehensive survey of the NEO population; (2) obtain detailed physical characterization data for individual objects that are likely to pose an impact hazard; (3) characterize the entire population of potentially hazardous NEOs to inform potential mitigation strategies. The mission will make significant progress toward the George E. Brown, Jr. NEO Survey Program objective defined by the U. S. Congress of detecting, tracking, cataloging, and characterizing at least 90% of NEOs equal to or larger than 140 m in diameter. The project is a collaboration between NASA-JPL, the University of Arizona (UA) and industry, with Ball Aerospace notably providing the spacecraft and key instrument elements. This paper will describe the overall NEO Surveyor Project objectives, initial spacecraft and instrument design and development plans and mission concept.

Veto, Michael↗
NASA NTRS2017

Using Information from Rendezvous Missions for Best-Case Appraisals of Impact Damage to Planet Earth Caused by Natural Objects

The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions about potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size range of 160 to 290 m in diameter to be discussed at the PDC 2017 is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) what is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its structure and heterogeneity from the surface and throughout its interior? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as inputs for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, andor cratering. Topics presented in this paper include: (i) the devastation predicted by 2017 PDCs impact on land based on initial observations using ATAPs risk assessment capability, (ii) how information corresponding to items (1) to (3) could be obtained from a rendezvous mission, and (iii) how information from a rendezvous mission could be used, along with that from ground observations and data from the literature to provide input for a new risk analysis capability that is emerging from ATAPs research. It is concluded that this approach would result in the creation of an appraisal of the threat from 2017 PDC with the least uncertainty possible, herein called the best-case.

Asteroid Impact Appraisals↗
NASA NTRS1991

An RF interference mitigation methodology with potential applications in scheduling

Software tools for interference analysis and mitigation were developed in the Communications Link Analysis and Simulation System (CLASS) environment for: communications performance evaluation; and mission planning. Potential applications are seen in analysis, evaluation, and optimization of user schedules. Tools producing required separation angles and potential interference intervals can be used as an aid to mutual interference mitigation within a scheduling system.

Wong, Yen F.↗
NASA NTRS2017

Using Information from Rendezvous Missions For Best-Case Appraisals of Impact Damage to Planet Earth Caused By Natural Objects

The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions on potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size of 160 to 290 m in diameter to be discussed at the PDC 2017 meeting is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) What is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its sub and interior structure? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as input for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, and/or cratering. Topics presented in this paper include: (i) The devastation predicted by 2017 PDCs impact based on initial observations using ATAPs risk assessment capability, (ii) How information corresponding to items (1) to (3) could be obtained from a rendezvous mission, and (iii) How information from a rendezvous mission could be used, along with that from ground observations and data from the literature, could provide input for an new risk analysis capability that is emerging from ATAPs research. It is concluded that this approach would result in appraisal with the least uncertainty possible (herein called the best-case) using simulation capabilities that are currently available or will be in the future.

Arnold, James O.↗
NASA NTRS2017

Using Information from Rendezvous Missions For Best-Case Appraisals of Impact Damage to Planet Earth Caused By Natural Objects

The Asteroid Threat Assessment Project (ATAP), a part of NASAs Planetary Defense Coordination Office (PDCO) has the responsibility to appraise the range of surface damage by potential asteroid impacts on land or water. If a threat is realized, the project will provide appraisals to officials empowered to make decisions on potential mitigation actions. This paper describes a scenario for assessment of surface damage when characterization of an asteroid had been accomplished by a rendezvous mission that would be conducted by the international planetary defense community. It is shown that the combination of data from ground and in-situ measurements on an asteroid provides knowledge that can be used to pin-point its impact location and predict the level of devastation it would cause. The hypothetical asteroid 2017 PDC with a size of 160 to 290 m in diameter to be discussed at the PDC 2017 meeting is used as an example. In order of importance for appraising potential damage, information required is: (1) where will the surface impact occur? (2) What is the mass, shape and size of the asteroid and what is its entry state (speed and entry angle) at the 100 km atmospheric pierce point? And (3) is the asteroid a monolith or a rubble pile? If it is a rubble pile, what is its sub and interior structure? Item (1) is of first order importance to determine levels of devastation (loss of life and infrastructure damage) because it varies strongly on the impact location. Items (2) and (3) are used as input for ATAPs simulations to define the level of surface hazards: winds, overpressure, thermal exposure; all created by the deposition of energy during the objects atmospheric flight, andor cratering. Topics presented in this paper include: (i) The devastation predicted by 2017 PDCs impact based on initial observations using ATAPs risk assessment capability, (ii) How information corresponding to items (1) to (3) could be obtained from a rendezvous mission, and (iii) How information from a rendezvous mission could be used, along with that from ground observations and data from the literature, could provide input for an new risk analysis capability that is emerging from ATAPs research. It is concluded that this approach would result in appraisal with the least uncertainty possible (herein called the best-case) using simulation capabilities that are currently available or will be in the future.

Arnold, J. O.↗
NASA NTRS2014

Space Radiation and the Challenges Towards Effective Shielding Solutions

The hazards of space radiation and their effective mitigation strategies continue to pose special science and technology challenges to NASA. It is widely accepted now that shielding space vehicles and structures will have to rely on new and innovative materials since aluminum, like all high Z materials, are poor shields against the particulate and highly ionizing nature of space radiation. Shielding solutions, motivated and constrained by power and mass limitations, couple this realization with "multifunctionality," both in design concept as well as in material function and composition. Materials endowed with effective shielding properties as well as with some degree of multi‐functionality may be the kernel of the so‐called "radiation‐smart" structures and designs. This talk will present some of the challenges and potential mitigation ideas towards the realization of such structures and designs.

Barghouty, Abdulnasser↗
NASA NTRS2006

WIse-2005: Combined Aerobic and Resistive Exercise May Help Mitigate Bone Loss During 60-D Simulated Microgravity in Women

Exercise can attenuate bone loss associated with disuse during bed rest (BR), an analog of space flight. Previous studies have examined the efficacy of aerobic or resistive exercise countermeasures, but not in combination. We sought to determine the effect of a combined resistive and aerobic exercise regimen on bone metabolism during BR. After a 20-d ambulatory adaptation to confinement and diet, 16 women participated in a 60-d head-down-tilt BR. Control subjects (CN, n=8) performed no countermeasures. Exercise subjects, (EX, n=8) participated in exercise alternating daily between supine treadmill exercise within lower body negative pressure and resistive fly-wheel exercise (6-d wk(sup -1)). In the last week of BR, bone resorption was greater (p less than 79 plus or minus 44%, mean plus or minus SD) and EX groups (64 50%). N-telopeptide also increased (CN: 51 plus or minus 34%; EX: 43 plus or minus 56%). However, bone-specific alkaline phosphatase, a bone formation marker, tended to be higher in EX (26 plus or minus 18%) than in CN (8 plus or minus 33%) groups. The combination of resistive and aerobic exercise does not prevent bone resorption, but may promote formation, potentially mitigating the net bone loss associated with simulated microgravity. This study was supported by CNES, CSA, ESA, NASA, and NASA grant NNJ04HF71G to ARH. MEDES (French Institute for Space Medicine and Physiology) organized the study.

Smith, Scott M.↗
NASA NTRS2014

NASA's Newest Orbital Debris Ground-based Telescope Assets: MCAT and UKIRT

NASA's Orbital Debris Program Office (ODPO) will break ground on Ascension Island in 2014 to build the newest optical (0.30 - 1.06 micrometers) ground-based telescope asset dedicated to the study of orbital debris. The Meter Class Autonomous Telescope (MCAT) is a 1.3m optical telescope designed to track objects in orbits ranging from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO). Ascension Island is located in the South Atlantic Ocean, offering longitudinal sky coverage not afforded by the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) network. With a fast-tracking dome, a suite of visible wide-band filters, and a time-delay integration (TDI) capable camera, MCAT is capable of multiple observing modes ranging from tracking cataloged debris targets to surveying the overall debris environment. Access to the United Kingdom Infrared Telescope (UKIRT) will extend our spectral coverage into the near- (0.8-5 micrometers) and mid- to far-infrared (8-25 micrometers) regime. UKIRT is a 3.8m telescope located on Mauna Kea on the Big Island of Hawaii. At nearly 14,000-feet and above the atmospheric inversion layer, this is one of the premier astronomical sites in the world and is an ideal setting for an infrared telescope. An unprecedented one-third of this telescope's time has been allocated to collect orbital debris data for NASA's ODPO over a 2-year period. UKIRT has several instruments available to obtain low-resolution spectroscopy in both the near-IR and the mid/far-IR. Infrared spectroscopy is ideal for constraining the material types, albedos and sizes of debris targets, and potentially gaining insight into reddening effects caused by space weathering. In addition, UKIRT will be used to acquire broadband photometric imaging at GEO with the Wide Field Camera (WFCAM) for studying known objects of interest as well as collecting data in survey-mode to discover new targets. Results from the first stage of the debris campaign will be presented. The combination of these ground-based telescope assets will yield spectral coverage ranging from 0.3 - 25 micrmeters, allowing orbital debris to be studied in depth across a wider wavelength range in the visible and IR than ever previously studied by ODPO. Located on opposite sides of the world and in opposite hemispheres, they offer access to nearly the entire GEO belt on any given night, allowing immediate coverage of nearly any time-critical break-up event. By expanding the methods for surveying, detecting, and characterizing orbital debris, we can better model the debris environment and ultimately gain insight into how to mitigate potential collisions for future missions.

Lederer, S. M.↗
NASA NTRS2010

J-2X Turbopump Cavitation Diagnostics

The J-2X is the upper stage engine currently being designed by Pratt & Whitney Rocketdyne (PWR) for the Ares I Crew Launch Vehicle (CLV). Propellant supply requirements for the J-2X are defined by the Ares Upper Stage to J-2X Interface Control Document (ICD). Supply conditions outside ICD defined start or run boxes can induce turbopump cavitation leading to interruption of J-2X propellant flow during hot fire operation. In severe cases, cavitation can lead to uncontained engine failure with the potential to cause a vehicle catastrophic event. Turbopump and engine system performance models supported by system design information and test data are required to predict existence, severity, and consequences of a cavitation event. A cavitation model for each of the J-2X fuel and oxidizer turbopumps was developed using data from pump water flow test facilities at Pratt & Whitney Rocketdyne (PWR) and Marshall Space Flight Center (MSFC) together with data from Powerpack 1A testing at Stennis Space Center (SSC) and from heritage systems. These component models were implemented within the PWR J-2X Real Time Model (RTM) to provide a foundation for predicting system level effects following turbopump cavitation. The RTM serves as a general failure simulation platform supporting estimation of J-2X redline system effectiveness. A study to compare cavitation induced conditions with component level structural limit thresholds throughout the engine was performed using the RTM. Results provided insight into system level turbopump cavitation effects and redline system effectiveness in preventing structural limit violations. A need to better understand structural limits and redline system failure mitigation potential in the event of fuel side cavitation was indicated. This paper examines study results, efforts to mature J-2X turbopump cavitation models and structural limits, and issues with engine redline detection of cavitation and the use of vehicle-side abort triggers to augment the engine redline system.

Santi, I. Michael↗
NASA NTRS2022

Clean Air Policies Are Key for Successfully Mitigating Arctic Warming

A tighter integration of modeling frameworks for climate and air quality is urgently needed to assess the impacts of clean air policies on future Arctic and global climate. We combined a new model emulator and comprehensive emissions scenarios for air pollutants and greenhouse gases to assess climate and human health co-benefits of emissions reductions. Fossil fuel use is projected to rapidly decline in an increasingly sustainable world, resulting in far-reaching air quality benefits. Despite human health benefits, reductions in sulfur emissions in a more sustainable world could enhance Arctic warming by 0.8 °C in 2050 relative to the 1995–2014, thereby offsetting climate benefits of greenhouse gas reductions. Targeted and technically feasible emissions reduction opportunities exist for achieving simultaneous climate and human health co-benefits. It would be particularly beneficial to unlock a newly identified mitigation potential for carbon particulate matter, yielding Arctic climate benefits equivalent to those from carbon dioxide reductions by 2050.

Atmospheric chemistry↗
NASA NTRS1980

Satellite Power System (SPS) laser studies. Volume 2: Meteorological effects on laser beam propagation and direct solar pumped lasers for the SPS

The primary emphasis of this research activity was to investigate the effect of the environment on laser power transmission/reception from space to ground. Potential mitigation techniques to minimize the environment effect by a judicious choice of laser operating parameters was investigated. Using these techniques, the availability of power at selected sites was determined using statistical meteorological data for each site.

Beverly, R. E., III↗
NASA NTRS1990

Inhomogeneities of stratocumulus liquid water

There is a growing body of observational evidence on inhomogeneous cloud structure, most recently from the extensive measurements of the FIRE field program. Knowledge of cloud structure is important because it strongly influences the cloud radiative properties, one of the major factors in determining the global energy balance. Current atmospheric circulation models use plane-parallel radiation, so that the liquid water in each gridbox is assumed to be uniform, which gives an unrealistically large albedo. In reality cloud liquid water occupies only a subset of each gridbox, greatly reducing the mean albedo. If future climate models are to treat the hydrological cycle in a manner consistent with energy balance, a better treatment of cloud liquid is needed. FIRE concentrated upon two cloud types of special interest: cirrus and marine stratocumulus. Cirrus tend to be high and optically thin, thus reducing the effective radiative temperature without increasing the albedo significantly, leading to an enhanced greenhouse heating. In contrast, marine stratocumulus are low and optically thick, thus producing a large increase in reflected radiation with a small change in emitted radiation, giving a net cooling which could potentially mitigate the expected greenhouse warming. The FIRE measurements in California stratocumulus during June and July of 1987 show variations in cloud liquid water on all scales. Such variations are associated with inhomogeneous entrainment, in which entrained dry air, rather than mixing uniformly with cloudy air, remains intact in blobs of all sizes, which decay only slowly by invasion of cloudy air. Two important stratocumulus observations are described, followed by a simple fractal model which reproduces these properties, and finally, the model radiative properties are discussed.

Cahalan, Robert F.↗
NASA NTRS1999

Triboelectric Charging in Simulated Mars Environment

Triboelectric charging of nonconducting materials followed by sudden electrostatic discharge (ESD) can damage electronic equipment and become ignition hazard to combustible materials. Mars atmosphere has near zero humidity and therefore natural charge bleeding to surroundings is anticipated to be limited. Potential mitigation of ESD problems has been conjectured based upon strong extraterrestrial radiation on Mars compared to earth. A hypothesis was formulated that ESD problem is less significant in simulated Mars condition since strong radiation and presence of argon will generate an ionized environment; this will be conducive to rapid bleeding of static charge into the surroundings.

Lee, R.↗
NASA NTRS2004

SUV Rollover Test

The National Highway Traffic Safety Administration (NHTSA) approached NASA to evaluate vehicle rollover resistance using the High Capacity Centrifuge Facility. Testing was planned for six different sport utility vehicles. Previous methods for simulating the rollover conditions were considered to be not indicative of the true driving conditions. A more realistic gradual application of side loading could be achieved by using a centrifuge facility. A unique load measuring lower support system was designed to measure tire loading on the inboard tires and to indicate tire liftoff. This lower support system was designed to more closely emulate the actual rollover conditions. Additional design features were provided to mitigate potential safety hazards.

Chambers, William V.↗
NASA NTRS2006

Synthetic Vision Enhanced Surface Operations and Flight Procedures Rehearsal Tool

Limited visibility has been cited as predominant causal factor for both Controlled-Flight-Into-Terrain (CFIT) and runway incursion accidents. NASA is conducting research and development of Synthetic Vision Systems (SVS) technologies which may potentially mitigate low visibility conditions as a causal factor to these accidents while replicating the operational benefits of clear day flight operations, regardless of the actual outside visibility condition. Two experimental evaluation studies were performed to determine the efficacy of two concepts: 1) head-worn display application of SVS technology to enhance transport aircraft surface operations, and 2) three-dimensional SVS electronic flight bag display concept for flight plan preview, mission rehearsal and controller-pilot data link communications interface of flight procedures. In the surface operation study, pilots evaluated two display devices and four display modes during taxi under unlimited and CAT II visibility conditions. In the mission rehearsal study, pilots flew approaches and departures in an operationally-challenged airport environment, including CFIT scenarios. Performance using the SVS concepts was compared to traditional baseline displays with paper charts only or EFB information. In general, the studies evince the significant situation awareness and enhanced operational capabilities afforded from these advanced SVS display concepts. The experimental results and conclusions from these studies are discussed along with future directions.

Arthur, Jarvis J., III↗
NASA NTRS2004

Thermal and Quantum Mechanical Noise of a Superfluid Gyroscope

A potential application of a superfluid gyroscope is for real-time measurements of the small variations in the rotational speed of the Earth, the Moon, and Mars. Such rotational jitter, if not measured and corrected for, will be a limiting factor on the resolution potential of a GPS system. This limitation will prevent many automation concepts in navigation, construction, and biomedical examination from being realized. We present the calculation of thermal and quantum-mechanical phase noise across the Josephson junction of a superfluid gyroscope. This allows us to derive the fundamental limits on the performance of a superfluid gyroscope. We show that the fundamental limit on real-time GPS due to rotational jitter can be reduced to well below 1 millimeter/day. Other limitations and their potential mitigation will also be discussed.

Chui, Talso↗