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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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At least 487 records · Page 27
All sourcesNASA NTRSDOE OSTI
NASA NTRS2012

Resolving Off-Nominal Situations in Schedule-Based Terminal Area Operations: Results from a Human-in-the-Loop Simulation

A recent human-in-the-loop simulation in the Airspace Operations Laboratory (AOL) at NASA's Ames Research Center investigated the robustness of Controller-Managed Spacing (CMS) operations. CMS refers to AOL-developed controller tools and procedures for enabling arrivals to conduct efficient Optimized Profile Descents with sustained high throughput. The simulation provided a rich data set for examining how a traffic management supervisor and terminal-area controller participants used the CMS tools and coordinated to respond to off-nominal events. This paper proposes quantitative measures for characterizing the participants responses. Case studies of go-around events, replicated during the simulation, provide insights into the strategies employed and the role the CMS tools played in supporting them.

Mercer, Joey↗
NASA NTRS2016

AF-M315E Propulsion System Advances and Improvements

Even as for the GR-1 awaits its first on-orbit demonstration on the planned 2017 launch of NASA's Green Propulsion Infusion Mission (GPIM) program, ongoing efforts continue to advance the technical state-of-the-art through improvements in the performance, life capability, and affordability of both Aerojet Rocketdyne's 1-N-class GR-1 and 20-N-class GR-22 green monopropellant thrusters. Hot-fire testing of a design upgrade of the GR-22 thruster successfully demonstrated resolution of a life-limiting thermo-structural issue encountered during prototype testing on the GPIM program, yielding both an approximately 2x increase in demonstrating life capability, as well as fundamental insights relating to how ionic liquid thrusters operate, thruster scaling, and operational factors affecting catalyst bed life. Further, a number of producibility improvements, related to both materials and processes and promising up to 50% unit cost reduction, have been identified through a comprehensive Design for Manufacturing and Assembly (DFMA) assessment activity recently completed at Aerojet Rocketdyne. Focused specifically on the GR-1 but applicable to the common-core architecture of both thrusters, ongoing laboratory (heavyweight) thruster testing being conducted under a Space Act Agreement at NASA Glenn Research Center has already validated a number of these proposed manufacturability upgrades, additionally achieving a greater than 40% increase in thruster life. In parallel with technical advancements relevant to conventional large spacecraft, a joint effort between NASA and Aerojet Rocketdyne is underway to prepare 1-U CubeSat AF-M315E propulsion module for first flight demonstration in 2018.

Liquid propulsion↗
NASA NTRS2000

Cyclic Oxidation Testing and Modelling: A NASA Lewis Perspective

The Materials Division of the NASA Lewis Research Center has been heavily involved in the cyclic oxidation of high temperature materials for 30 years. Cyclic furnace and burner rig apparati have been developed, refined, and replicated to provide a large scale facility capable of evaluating many materials by a standard technique. Material behavior is characterized by weight change data obtained throughout the test, which has been modelled in a step-wise process of scale growth and spallation. This model and a coupled diffusion model have successfully described cyclic behavior for a number of systems and have provided insights regarding life prediction and variations in the spalling process. Performance ranking and mechanistic studies are discussed primarily for superalloys and coating alloys. Similar cyclic oxidation studies have been performed on steels, intermetallic compounds, thermal barrier coatings, ceramics, and ceramic composites. The most common oxidation test was performed in air at temperatures ranging from 800 deg. to 1600 C, for times up to 10000 h, and for cycle durations of 0.1 to 1000 h. Less controlled, but important, test parameters are the cooling temperature and humidity level. Heating and cooling rates are not likely to affect scale spallation. Broad experience has usually allowed for considerable focus and simplification of these test parameters, while still revealing the principal aspects of material behavior and performance. Extensive testing has been performed to statistically model the compositional effects of experimental alloys and to construct a comprehensive database of complex commercial alloys.

Smialek, J. L.↗
NASA NTRS2011

Summary of Results from Space Shuttle Main Engine Off-Nominal Testing

This paper is a summary of Space Shuttle Main Engine (SSME) off-nominal testing that occurred during 2008 and 2009. During the last two years of planned SSME testing at Stennis Space Center, Pratt & Whitney Rocketdyne worked with their NASA MSFC customer to systematically identify, develop, assess, and implement challenging test objectives in order to expand the knowledge of one of the world s most reliable and highly tested large rocket engine. The objectives successfully investigated three main areas of interest expanding engine performance margins, demonstrating system operational capabilities, and establishing ground work for new rocket engine technology. The testing gave the Space Shuttle Program new options to safely fly out the flight manifest and provided Pratt & Whitney Rocketdyne and NASA new insight into the operational capabilities of the SSME, capabilities which can be used in assessing potential future applications of the RS-25 engine.

Horton, James F.↗
NASA NTRS2024

Assessment of Secondary Pitot Probe Locations on a Small UAS

Urban Air Mobility (UAM) and Advanced Air Mobility (AAM) have been at the forefront of many aeronautical discussions because of the potential revolutionary improvement to urban transportation. In this study, a representative Research Aircraft for eVTOL Enabling techNologies, Sub-scale Wind Tunnel Flight Test (RAVEN SWFT) nosecone was placed inside the NASA Langley Research Center’s 12-Foot Low-Speed Wind Tunnel with a pitot-static assembly installed. The study aimed to determine a suitable location and orientation of the pitot-static assembly on the nose of the vehicle, which consists of two airspeed sensors: one for the flight controller and one for data collection. The dynamic pressure was varied from 0.5 to 5psf for each test point. Additionally, three different offset distances from the center boom and three different angles for the flight controller pitot tube were tested. The data from both of the pitot tube assemblies were compared to the wind tunnel and the Aeroprobe pitot tube. The results show the flight controller pitot tube performs better when it is placed further away from the nosecone, regardless of the angle. The results also show that the angle does not affect the accuracy of the pitot tube when the vehicle yaws or pitches regardless of the mounting angle and location. The study provides useful insights for the design of the airspeed measurement systems on small Uncrewed Aerial Systems (sUAS), which can be applied to other UAM and AAM applications.

AAM↗
NASA NTRS1997

National Institutes of Health, Rodent 4 (NIH.R4); Calcium Metabolism and Vascular Function After Spaceflight: A Collaborative Series with NASA and NIH

The NIH.R4 payload was a collaborative experiment conducted by NASA's Ames Research Center in conjunction with the National Institutes of Health (NIH). This middeck payload was the fourth in a series of experiments focusing on developmental biology and the effects of microgravity on mammalian systems. The NIH.R4 payload was flown onboard STS-80, which launched November 19, 1996, and landed at Kennedy Space Center on December 7, 1996, and was the longest shuttle mission to date. Fourteen male Spontaneously Hypertensive rats (SHR) were flown; seven in each of two Animal Enclosure Modules (AEM) in the shuttle middeck. The flight animals were exposed to 18 days of microgravity. Two synchronous control groups were utilized for this study in addition to an asynchronous post-flight AEM control study conducted at the PI lab. The animals were fed two different calcium diets in the NASA food bar (2.0% and 0.2%) three weeks prior to launch and insight. Blood pressures were taken at pre-determined intervals and were the basis for flight selection. Upon recovery Dwight animals blood pressure was measured and a variety of tissues were collected. Project testing and data will be presented.

Reiss-Bubenheim, Debra↗
NASA NTRS2010

An Analysis of Rocket Propulsion Testing Costs

The primary mission at NASA Stennis Space Center (SSC) is rocket propulsion testing. Such testing is commonly characterized as one of two types: production testing for certification and acceptance of engine hardware, and developmental testing for prototype evaluation or research and development (R&D) purposes. For programmatic reasons there is a continuing need to assess and evaluate the test costs for the various types of test campaigns that involve liquid rocket propellant test articles. Presently, in fact, there is a critical need to provide guidance on what represents a best value for testing and provide some key economic insights for decision-makers within NASA and the test customers outside the Agency. Hence, selected rocket propulsion test databases and references have been evaluated and analyzed with the intent to discover correlations of technical information and test costs that could help produce more reliable and accurate cost projections in the future. The process of searching, collecting, and validating propulsion test cost information presented some unique obstacles which then led to a set of recommendations for improvement in order to facilitate future cost information gathering and analysis. In summary, this historical account and evaluation of rocket propulsion test cost information will enhance understanding of the various kinds of project cost information; identify certain trends of interest to the aerospace testing community.

Ramirez, Carmen↗
NASA NTRS2011

Orbital Debris Characterization via Laboratory Optical Measurements

Optical observations of orbital debris offer insights that differ from radar measurements (specifically the size parameter,wavelength regime,and altitude range). For example, time-dependent photometric data yield lightcurves in multiple bandpasses that aid in material identification and possible periodic orientations. These data can also be used to help identify shapes and optical properties at multiple phase angles. Capitalizing on optical data products and applying them to generate a more complete understanding of orbital objects is a key objective of NASA's Optical Measurement Program, and the primary reason for the creation of the Optical Measurements Center(OMC). The OMC attempts to emulate space-based illumination conditions using equipment and techniques that parallel telescopic observations and source-target-sensor orientations.

Cowardin, Healther↗
NASA NTRS2002

Measurements of Turbulent Flow Field in Separate Flow Nozzles with Enhanced Mixing Devices - Test Report

As part of the Advanced Subsonic Technology Program, a series of experiments was conducted at NASA Glenn Research Center on the effect of mixing enhancement devices on the aeroacoustic performance of separate flow nozzles. Initial acoustic evaluations of the devices showed that they reduced jet noise significantly, while creating very little thrust loss. The explanation for the improvement required that turbulence measurements, namely single point mean and RMS statistics and two-point spatial correlations, be made to determine the change in the turbulence caused by the mixing enhancement devices that lead to the noise reduction. These measurements were made in the summer of 2000 in a test program called Separate Nozzle Flow Test 2000 (SFNT2K) supported by the Aeropropulsion Research Program at NASA Glenn Research Center. Given the hot high-speed flows representative of a contemporary bypass ratio 5 turbofan engine, unsteady flow field measurements required the use of an optical measurement method. To achieve the spatial correlations, the Particle Image Velocimetry technique was employed, acquiring high-density velocity maps of the flows from which the required statistics could be derived. This was the first successful use of this technique for such flows, and shows the utility of this technique for future experimental programs. The extensive statistics obtained were likewise unique and give great insight into the turbulence which produces noise and how the turbulence can be modified to reduce jet noise.

Bridges, James↗
NASA NTRS2015

An Integrated Physics-Based Risk Model for Assessing the Asteroid Threat

Although most asteroids and other near-Earth objects (NEOs) do not pose a threat to Earth’s inhabitants, impacts from objects that are just tens of meters in diameter can cause significant damage if they occur over a populated area. This paper forms the foundation of an effort at NASA Ames Research Center to quantify these risks and identify the greatest risk-driving parameters and uncertainties. An integrated risk model that couples dynamic probabilistic simulations of strike occurrences with physics-based models of NEO impact damage factors has been developed to generate casualty estimates for a range of NEO impact properties. Currently, the model focuses on the risk due to blast overpressure damage from airbursts and impacts on land. The model is first used to reproduce results from established sources, and then is extended to perform sensitivity studies that yield greater insights into risk driving parameters. Results show that meteor strength and entry angle play a role for small to mid-size NEOs, and that accounting for the specific target location significantly affects casualty estimates and dominates the risk. Future work will continue to refine and expand the models to better characterize key impact risk factors, include additional types of threats such as tsunamis and climate effects, and ultimately support assessments of potential asteroid mitigation strategies.

Asteroid Threat↗
NASA NTRSDate not supplied

Multidimensional Data Aggregation in the Cloud with Application to Geostationary Satellite-based Air Quality Monitoring

Scientists use satellite data for studying Earth's systems, and the remote sensing data that these satellites collect are typically separated into files of a size small enough for efficient network transfer and storage. However, researchers usually prefer to analyze the data based on real-world dimensions like time, space, or elevation. To help with this, NASA's Atmospheric Science Data Center (ASDC) developed a new cloud-based tool that combines these smaller data chunks into larger, more useful datasets. The tool works on Network Common Data Form (netCDF4) and some HDF5 formatted files, and it is available as a service in NASA's Earthdata Cloud. In this presentation, we showcase this service using data from the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument. By combining TEMPO's continuous observations over time, we create longer and more informative analysis-ready time series to facilitate the study of air quality patterns. Insights gained will provide a more comprehensive understanding of pollution sources, transport patterns, and their effects on the environment and human health.

Daniel Kaufman↗
NASA NTRS1994

Hormonal and metabolic responses of hypophysectomized rats with head-down suspension

The primary purpose of this investigation was to secure select anatomical and physiological measurements from hypophysectomized rats and their sham-operated control to determine how various endocrine influences could be modified by conditions of simulated microgravity. The focal point of the study was the exercise responses after head-down suspension; however, we were also interested in obtaining insights on nonexercise-related mechanisms. Since more details and information concerning this study will be published elsewhere, we will highlight those findings which warrant further research.

NASA Program Space Physiology and Countermeasures↗
NASA NTRS2003

Opening Loads Analyses for Various Disk-Gap-Band Parachutes

Detailed opening loads data is presented for 18 tests of Disk-Gap-Band (DGB) parachutes of varying geometry with nominal diameters ranging from 43.2 to 50.1 ft. All of the test parachutes were deployed from a mortar. Six of these tests were conducted via drop testing with drop test vehicles weighing approximately 3,000 or 8,000 lb. Twelve tests were conducted in the National Full-Scale Aerodynamics Complex 80- by 120-foot wind tunnel at the NASA Ames Research Center. The purpose of these tests was to structurally qualify the parachute for the Mars Exploration Rover mission. A key requirement of all tests was that peak parachute load had to be reached at full inflation to more closely simulate the load profile encountered during operation at Mars. Peak loads measured during the tests were in the range from 12,889 to 30,027 lb. Of the two test methods, the wind tunnel tests yielded more accurate and repeatable data. Application of an apparent mass model to the opening loads data yielded insights into the nature of these loads. Although the apparent mass model could reconstruct specific tests with reasonable accuracy, the use of this model for predictive analyses was not accurate enough to set test conditions for either the drop or wind tunnel tests. A simpler empirical model was found to be suitable for predicting opening loads for the wind tunnel tests to a satisfactory level of accuracy. However, this simple empirical model is not applicable to the drop tests.

Cruz, J. R.↗
NASA NTRS2005

Overview of Advanced Electromagnetic Propulsion Development at NASA Glenn Research Center

NASA Glenn Research Center s Very High Power Electric Propulsion task is sponsored by the Energetics Heritage Project. Electric propulsion technologies currently being investigated under this program include pulsed electromagnetic plasma thrusters, magnetoplasmadynamic thrusters, helicon plasma sources as well as the systems models for high power electromagnetic propulsion devices. An investigation and evaluation of pulsed electromagnetic plasma thruster performance at energy levels up to 700 Joules is underway. On-going magnetoplasmadynamic thruster experiments will investigate applied-field performance characteristics of gas-fed MPDs. Plasma characterization of helicon plasma sources will provide additional insights into the operation of this novel propulsion concept. Systems models have been developed for high power electromagnetic propulsion concepts, such as pulsed inductive thrusters and magnetoplasmadynamic thrusters to enable an evaluation of mission-optimized designs.

Pencil, Eric J.↗
NASA NTRS2010

Metal/Silicate Partitioning at High Pressures and Temperatures

The behavior of siderophile elements during metal-silicate segregation, and their resulting distributions provide insight into core formation processes. Determination of partition coefficients allows the calculation of element distributions that can be compared to established values of element abundances in the silicate (mantle) and metallic (core) portions of the Earth. Moderately siderophile elements, including W, are particularly useful in constraining core formation conditions because they are sensitive to variations in T, P, oxygen fugacity (fO2), and silicate composition. To constrain the effect of pressure on W metal/silicate partitioning, we performed experiments at high pressures and temperatures using a multi anvil press (MAP) at NASA Johnson Space Center and laser-heated diamond anvil cells (LHDAC) at the University of Maryland. Starting materials consisted of natural peridotite mixed with Fe and W metals. Pressure conditions in the MAP experiments ranged from 10 to 16 GPa at 2400 K. Pressures in the LHDAC experiments ranged from 26 to 58 GPa, and peak temperatures ranged up to 5000 K. LHDAC experimental run products were sectioned by focused ion beam (FIB) at NASA JSC. Run products were analyzed by electron microprobe using wavelength dispersive spectroscopy. Liquid metal/liquid silicate partition coefficients for W were calculated from element abundances determined by microprobe analyses, and corrected to a common fO2 condition of IW-2 assuming +4 valence for W. Within analytical uncertainties, W partitioning shows a flat trend with increasing pressure from 10 to 16 GPa. At higher pressures, W becomes more siderophile, with an increase in partition coefficient of approximately 0.5 log units.

Shofner, G.↗
NASA NTRS2026

Pulsed Electroacoustic Analysis Capabilities at NASA Glenn Research Center

The High Voltage Testing Laboratory at NASA Glenn Research Center is equipped with a pulsed electroacoustic (PEA) analyzer to study space charge phenomena in dielectric materials. Dielectric materials such as those used in high voltage insulation systems are of great interest due to their crucial role in withstanding high voltages and avoiding electrical breakdown in electrified aircraft power systems. Current research is underway for the development of novel lightweight electrical insulation and the thorough evaluation of these materials is required. The PEA instrumentation at NASA GRC is a nondestructive method to evaluate the space charge phenomena which can give a unique insight on the feasibility and lifetime of material systems. The instrumentation capability and initial results are reported here.

pulsed electroacoustic↗
NASA NTRS2015

Development of an Infrared Lamp Array for the Smap Spacecraft Thermal Balance Test

NASA launched the SMAP observatory in January 2015 aboard a Delta II into a sun-synchronous orbit around Earth. The science payload of a radar and a radiometer utilizes a shared rotating six-meter antenna to provide a global map of the Earth's soil moisture content and its freeze/thaw state on a global, high-resolution scale in this three-year mission. An observatory-level thermal balance test conducted in May/June 2014 validated the thermal design and demonstrated launch readiness as part of the planned environmental test campaign. An infrared lamp array was designed and used in the thermal balance test to replicate solar heating on the solar array and sunlit side of the spacecraft that would normally be seen in orbit. The design, implementation, and operation of an infrared lamp array used for this nineteen-day system thermal test are described in this paper. Instrumental to the smooth operation of this lamp array was a characterization test performed in the same chamber two months prior to the observatory test to provide insight into its array operation and flux uniformity. This knowledge was used to identify the lamp array power settings that would provide the worst case predicted on-orbit fluxes during eclipse, cold, and hot cases. It also showed the lamp array variation when adjustments in flux were needed. Calorimeters calibrated prior to testing determined a relationship between calorimeter temperature and lamp array flux. This allowed the team to adjust the lamp output for the desired absorbed flux on the solar array. Flux levels were within 10% of the desired value at the center of the solar array with an ability to maintain these levels within 5% during steady state cases. All tests demonstrated the infrared lamp array functionality and furthered lamp array understanding for modeling purposes. This method contributed to a high-fidelity environmental simulation, which was required to replicate the extreme on-orbit thermal environments.

Miller, Jennifer R.↗
NASA NTRSDate not supplied

Thermal Protection System P50 Cork Char Response Characterization to Ascent Flight Shear and Heating Environments

NASA’s Space Launch System (SLS) experienced deflagration of the acreage of the Core Stage base heat shield during the Green Run hot-fire test campaigns and Artemis I flight. The burning products from the base heat shield during Green Run hot-fire test operation led to concerns in aerothermal environments and thermal protection system (TPS) performance prior to Artemis I flight. Updated design thermal environments accounting for cork combustion were developed using Green Run measurements and assessed prior to Artemis I, resulting in increased TPS thickness for the base heat shield. This work documents a highly controlled ground test within the NASA Marshall Space Flight Center’s Propulsion Test Branch Hot Gas Facility (HGF) and investigates the P50 cork TPS response due to sensitivity changes in radiative heat rates and surface shear stress. Prior to testing at the HGF, most of the P50 cork panels had a thick layer of char due to the cork combustion process replicated in a thermal vacuum chamber. SLS ascent shear stress and heating rate profile were simulated within the HGF by running the combustion-driven wind tunnel at off-nominal conditions and Mach numbers below 1. This test data provided insight into aerothermal measurements from Artemis I flight as well as informing updated base heating design environments for Artemis II. An in-depth understanding of the TPS P50 cork char response and observations is presented for launch vehicle flight ascent environments.

aerothermodynamics↗