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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS2017

Ground-Based Observing Campaign of Briz-M Debris

In 2015, NASA's Orbital Debris Program Office (ODPO) completed the installation of the Meter Class Autonomous Telescope (MCAT) on Ascension Island. MCAT is a 1.3m optical telescope designed with a fast tracking capability for observing orbital debris at all orbital regimes (Low-Erath orbits to Geosyncronous (GEO) orbits) from a low latitude site. This new asset is dedicated year-round for debris observations, and its location fills a geographical gap in the Ground-based Electro Optical Space Surveillance (GEODSS) network. A commercial off the shelf (COTS) research grade 0.4m telescope (named the Benbrook telescope) will also be installed on Ascension at the end of 2016. This smaller version is controlled by the same master software, designed by Euclid Research, and can be tasked to work independently or in concert with MCAT. Like MCAT, it has a the same suite of filters, a similar field of view, and a fast-tracking Astelco mount, and is also capable of tracking debris at all orbital regimes. These assets are well suited for targeted campagins or surveys of debris. Since 2013, NASA's ODPO has also had extensive access to the 3.8m infrared UKIRT telescope, located on Mauna Kea. At nearly 14,000-ft, this site affords excellent conditions for collecting both photometery and spectroscopy at near-IR (0.9 - 2.5 micrometers SWIR) and thermal-IR (8 - 25 micrometers; LWIR) regimes, ideal for investigating material properties as well as thermal characteristics and sizes of debris. For the purposes of understanding orbital debris, taking data in both survey mode as well as targeting individual objects for more in-depth characterizations are desired. With the recent break-ups of Briz-M rocket bodies, we have collected a suite of data in the optical, near-infrared, and mid-infrared of in-tact objects as well as those classified as debris. A break-up at GEO of a Briz-M rocket occurred in January, 2016, well timed for the first remote observing survey-campaign with MCAT. Access to the 3.8m UKIRT telescope has also allowed for investigating this break-up in the near-infrared at wavelengths where debris is often much more reflective, allowing for the potential detection of a smaller population of these debris. In addition, a suite of near-IR reflectance spectroscopy (0.8-2.5 micrometers) and thermal-IR (8-15 micrometers) of individual in-tact and debris Briz-M objects has been collected. Analysis of the survey data will be discussed.

Lederer, S. M.↗
NASA NTRS1973

Introduction to Voigt's wind power plant

The design and operation of a 100 kilowatt wind driven generator are reported. Its high speed three-bladed turbine operates at a height of 50 meters. Blades are rigidly connected to the hub and turbine revolutions change linearly with wind velocity, maintaining a constant speed ratio of blade tip velocity to wind velocity over the full predetermined wind range. Three generators installed in the gondola generate either dc or ac current. Based on local wind conditions, the device has a maximum output of 720 kilowatts at a wind velocity of 16 meters per second. Total electrical capacity is 750 kilowatts, and power output per year is 2,135,000 kilowatt/hours.

Tompkin, J.↗
NASA NTRS1979

Effects of steady-state pressure distortion on the stall margin of a J85-21 turbojet engine

The effects of the inlet pressure distortions, induced by five screen patterns, on the performance of a J85-21 turbojet engine was conducted at the NASA Lewis Research Center. Testing was in support of the HiMAT RPRV program at Dryden Flight Research Center. Distortion patterns were chosen based on anticipated application of test results of the HiMAT installation. Tests were conducted at a simulated Mach number and altitude condition of 0.9 and 10 973 meters. Results are presented in terms of distortion levels and standard compressor performance parameters.

Bobula, G. A.↗
NASA NTRS1987

Effects of Structural Errors on Parameter Estimates

Paper introduces concept of near equivalence in probability between different parameters or mathematical models of physical system. One in series of papers, each establishes different part of rigorous theory of mathematical modeling based on concepts of structural error, identifiability, and equivalence. This installment focuses upon effects of additive structural errors on degree of bias in estimates parameters.

Hadaegh, F. Y.↗
NASA NTRS1986

Multipurpose aircraft monitoring with a smart recorder

This paper describes a microprocessor-based flight recorder the 'Smart Recorder' - which was developed and installed on a King Air aircraft used for commercial charter service. The recorder is used as a research tool for developing monitoring strategies and processing algorithms to: (1) characterize the typical flight environment encountered by the host aircraft, (2) develop technology for automated engine trend monitoring, and (3) implement a crash recording capability. Initially the recorder was used as an adaptive data acquisition system, monitoring engine sensors and flight instruments and then modifying its data acquisition in response to the perceived aircraft situation. Data collected in this manner were stored in a removable bubble memory and subsequently analyzed in the laboratory. Later, on-board processing was implemented to better utilize the available storage capacity.

White, J. H.↗
NASA NTRS1993

Conversion of the proprietary ROLM (tm) inter-node link from multimode to singlemode operation

Many NASA centers have selected ROLM(TM) Computerized Branch Exchanges (CBX's) as their standard telephone exchange. The ROLM 9751 CBX Model 70 with ROLM software release 9005 can inter-communicate as a 'multi-node' system over a multimode fiber optic link of 450 to 6,000 meters. Singlemode fiber installations are not supported by ROLM. Two New Mexico-based NASA satellite ground terminals were already connected via a 6 kilometer singlemode fiber optic link. The ROLM Inter-Node Link (INL) was converted from multimode LED transmitters to singlemode laser transmitters and two ROLM CBX systems were interconnected using the modified INL. On activation, the system operated normally and has done so for six months. System testing indicates sufficient margin to drive 45 kilometers of singlemode fiber, an important benefit for widely separated facilities.

Boucher, Larry↗
NASA NTRS1996

Performance Evaluation in Network-Based Parallel Computing

Network-based parallel computing is emerging as a cost-effective alternative for solving many problems which require use of supercomputers or massively parallel computers. The primary objective of this project has been to conduct experimental research on performance evaluation for clustered parallel computing. First, a testbed was established by augmenting our existing SUNSPARCs' network with PVM (Parallel Virtual Machine) which is a software system for linking clusters of machines. Second, a set of three basic applications were selected. The applications consist of a parallel search, a parallel sort, a parallel matrix multiplication. These application programs were implemented in C programming language under PVM. Third, we conducted performance evaluation under various configurations and problem sizes. Alternative parallel computing models and workload allocations for application programs were explored. The performance metric was limited to elapsed time or response time which in the context of parallel computing can be expressed in terms of speedup. The results reveal that the overhead of communication latency between processes in many cases is the restricting factor to performance. That is, coarse-grain parallelism which requires less frequent communication between processes will result in higher performance in network-based computing. Finally, we are in the final stages of installing an Asynchronous Transfer Mode (ATM) switch and four ATM interfaces (each 155 Mbps) which will allow us to extend our study to newer applications, performance metrics, and configurations.

Dezhgosha, Kamyar↗
NASA NTRS1997

Microfabricated Ice-Detection Sensor

Knowledge of ice conditions on important aircraft lift and control surfaces is critical for safe operation. These conditions can be determined with conventional ice-detection sensors, but these sensors are often expensive, require elaborate installation procedures, and interrupt the airflow. A micromachined, silicon-based, flush-mounted sensor which generates no internal heat has been designed, batch fabricated, packaged, and tested. The sensor is capable of distinguishing between an ice-covered and a clean surface. It employs a bulk micromachined wafer with a 7 micrometer-thick, boron-doped, silicon diaphragm which serves as one plate of a parallel-plate capacitor. This is bonded to a second silicon wafer which contains the fixed electrodes, one to drive the diaphragm by application of a voltage, the other to measure the deflection by a change in capacitance. The diaphragm sizes ranged from 1x1 mm to 3x3 mm, and the gap between parallel-plate capacitors is 2 micrometers. A 200 V d.c. was applied to the driving electrode which caused the capacitance to increase approximately 0.6pf, from a nominal capacitance of 0.6pf, when the surface was ice free. After the sensor was cooled below the freezing point of water, the same voltage range was applied to the drive electrode. The capacitance increased by the same amount. Then a drop of water was placed over the diaphragm and allowed to freeze. This created an approximately 2mm-thick ice layer. The applied 200V d.c. produced no change in capacitance, confirming that the diaphragm was locked to the ice layer. Since the sensor uses capacitive actuation, it uses very little power and is an ideal candidate for inclusion in a wireless sensing system.

DeAnna, Russell G.↗
NASA NTRS2000

Interferometric Techniques for Gravitational Wave Detection in Space

The Laser Interferometer Space Antenna (LISA) mission will detect gravitational waves from galactic and extragalactic sources, most importantly those involving supermassive black holes. The primary goal of this project is to investigate stability and robustness issues associated with LISA interferometry. We specifically propose to study systematic errors arising from: optical misalignments, optical surface errors, thermal effects and pointing tolerances. This report covers the first fiscal year of the grant, from January 1st to December 31st 1999. We have employed an optical modeling tool to evaluate the effect of misplaced and misaligned optical components. Preliminary results seem to indicate that positional tolerances of one micron and angular tolerances of 0.6 millirad produce no significant effect on the achievable contrast of the interference pattern. This report also outlines research plans for the second fiscal year of the grant, from January 1st to December 31st 2000. Since the work under NAG5-6880 has gone more rapidly than projected, our test bed interferometer is operational, and can be used for measurements of effects that cause beam motion. Hence, we will design, build and characterize a sensor for measuring beam motion, and then install it. We are also planning a differential wavefront sensor based on a quadrant photodiode as a first generation sensor.

Stebbins, Robin T↗
NASA NTRSDate not supplied

A Warm Garage for a Lunar Rover

Approach: One approach to heating a rover during the lunar night is the so-called thermal wadis concept [1]. This involves heating the regolith with solar concentrators and placing the rover on the heated surface for the night. Since the regolith is heated by a relatively weak heat flux, a high thermal conductivity is required for heating a sufficiently large mass of regolith. However, lunar regolith has a low thermal conductivity. Therefore, the concept involves increasing the conductivity by sintering the regolith, which requires a significant energy input and complex procedures. Here we propose an alternative approach where the low thermal conductivity of regolith is an advantage. Specifically, we propose to use a highly exothermic combustible mixture for heat generation. The mixture pellets are placed in the surface layer of regolith and ignited. The combustion forms condensed products and releases heat, which then slowly spreads to the surrounding regolith. Heat can also be transferred, for example, by heat pipes, into radiant heating surfaces installed on the ground. A greenhouse that transmits sunlight during the day and decreases the radiative heat losses during the night can also be installed. Selection of the Heat-generating Mixture: The reactive mixture should have a high specific energy and generate only condensed products since gases could disturb the regolith layer, carry enthalpy out of the system, and lead to an explosion. There are mixtures, (sometimes called pyrolants) that possess very high specific energies. One example is magnesium-Teflon-Viton mixtures used in flares. However, they produce gases and may cause explosions. Other mixtures that include magnesium cannot be used either because of the high vapor pressure of Mg at temperatures well below the combustion temperature. Recently, mixtures that involve lithium peroxide (Li2O2) have been proposedfor using in space power systems [2]. However, they produce lithium oxide (Li2O), which boils at 2800 K at 1 atm and hence at a lower temperature in vacuum. Fortunately, there exist many mixtures that release a lot of heat and form only condensed products during the combustion. Many such mixtures have been used for self-propagating high-temperature synthesis (SHS) of various materials [3, 4]. For the application discussed here, t itanium/boron (1:2 mole ratio) mixture appears to be particularly promising. The specific energy is 4.0 MJ/kg (1.1 kWh/kg), the adiabatic flame temperature is about 3200 K, and the reaction forms solid titanium diboride (TiB2, melting point: 3500 K). The mixture can be ignited easily with a heated tungsten wire, and it has been used widely as a booster to ignite the main mixture in the SHS process.Estimates: Assuming that specific heat of regolith is 500 J/(kg∙K) [5] and all generated heat is transferred to regolith, 12.5 kg of the Ti/B mixture would increase the temperature of 1000 kg of regolith by 100 K. To evaluate the rate of heat transfer in the regolith, a spherical model was analyzed where the heat released by a 12.5 kg Ti/B core propagates by thermal conduction through a 1000 kg regolith shell with no heat loss from its outer surface. At a bulk density of 1500 kg/m3 [5], the radius of the shell was 54 cm, while the radius of the core was about 11 cm. The calculations were conducted using Thermal Desktop SINDA/FLUINT (Cullimore and Ring Technologies) software at two constant values of bulk thermal conductivityk of the regolith: 0.001 and 0.01 W/(m∙K). The results show that after 14.5 days the core lost 31% of the released heat at the lower k and 77% at the higher k. At a distance of 20 cm from the core surface, the temperature of the regolith increased by only 1 K at the lower k and by 132 K at the higher k. In reality, the regolith near the heat source will be melted, so its thermal conductivity will increase significantly. Nevertheless, the conducted estimates indicate that combustion-based heat generators, placed directly in the regolith, could provide heat during a rather long period such as the lunar night.Conclusion: Heat generators based on gasless combustion of highly energetic reactive mixtures could be installed directly in the surface layer of lunar regolith. Because of the low thermal conductivity of the regolith, such generators would keep thermal energy for days and gradually supply heat to a rover/lander.Acknowledgment: The material presented in this work is based upon the work supported by National Aeronautics and Space Administration (NASA) under Grant #80NSSC20K0293.References: [1] Balasubramaniam R. et al. (2011) J. Thermophys. Heat Trans., 25,130−139. [2] Blair R.G. and Vasu S.S. (2022) Conf. Advanced Power Systems for Deep Space Exploration. [3] Varma A. et al. (1998) Adv. Chem. Eng., 24,79−226. [4] Levashov E.A. et al. (2017) Int. Mater. Rev., 62,203−239. [5] Wood-Robinson R. et al. (2019) J. Geophys. Res. Planets, 124, 1989−2011.

lunar↗
NASA NTRS1976

MINIS: Multipurpose Interactive NASA Information System

The Multipurpose Interactive NASA Information Systems (MINIS) was developed in response to the need for a data management system capable of operation on several different minicomputer systems. The desired system had to be capable of performing the functions of a LANDSAT photo descriptive data retrieval system while remaining general in terms of other acceptable user definable data bases. The system also had to be capable of performing data base updates and providing user-formatted output reports. The resultant MINI System provides all of these capabilities and several other features to complement the data management system. The MINI System is currently implemented on two minicomputer systems and is in the process of being installed on another minicomputer system. The MINIS is operational on four different data bases.

Source record↗
NASA NTRS2007

NASA Tech Briefs, December 2007

Topics include: Ka-Band TWT High-Efficiency Power Combiner for High-Rate Data Transmission; Reusable, Extensible High-Level Data-Distribution Concept; Processing Satellite Imagery To Detect Waste Tire Piles; Monitoring by Use of Clusters of Sensor-Data Vectors; Circuit and Method for Communication Over DC Power Line; Switched Band-Pass Filters for Adaptive Transceivers; Noncoherent DTTLs for Symbol Synchronization; High-Voltage Power Supply With Fast Rise and Fall Times; Waveguide Calibrator for Multi-Element Probe Calibration; Four-Way Ka-Band Power Combiner; Loss-of-Control-Inhibitor Systems for Aircraft; Improved Underwater Excitation-Emission Matrix Fluorometer; Metrology Camera System Using Two-Color Interferometry; Design and Fabrication of High-Efficiency CMOS/CCD Imagers; Foam Core Shielding for Spacecraft CHEM-Based Self-Deploying Planetary Storage Tanks Sequestration of Single-Walled Carbon Nanotubes in a Polymer PPC750 Performance Monitor Application-Program-Installer Builder Using Visual Odometry to Estimate Position and Attitude Design and Data Management System Simple, Script-Based Science Processing Archive Automated Rocket Propulsion Test Management Online Remote Sensing Interface Fusing Image Data for Calculating Position of an Object Implementation of a Point Algorithm for Real-Time Convex Optimization Handling Input and Output for COAMPS Modeling and Grid Generation of Iced Airfoils Automated Identification of Nucleotide Sequences Balloon Design Software Rocket Science 101 Interactive Educational Program Creep Forming of Carbon-Reinforced Ceramic-Matrix Composites Dog-Bone Horns for Piezoelectric Ultrasonic/Sonic Actuators Benchtop Detection of Proteins Recombinant Collagenlike Proteins Remote Sensing of Parasitic Nematodes in Plants Direct Coupling From WGM Resonator Disks to Photodetectors Using Digital Radiography To Image Liquid Nitrogen in Voids Multiple-Parameter, Low-False-Alarm Fire-Detection Systems Mosaic-Detector-Based Fluorescence Spectral Imager Plasmoid Thruster for High Specific-Impulse Propulsion Analysis Method for Quantifying Vehicle Design Goals Improved Tracking of Targets by Cameras on a Mars Rover Sample Caching Subsystem Multistage Passive Cooler for Spaceborne Instruments GVIPS Models and Software Stowable Energy-Absorbing Rocker-Bogie Suspensions

Source record↗
NASA NTRS2010

A GPS-Based Pitot-Static Calibration Method Using Global Output-Error Optimization

Pressure-based airspeed and altitude measurements for aircraft typically require calibration of the installed system to account for pressure sensing errors such as those due to local flow field effects. In some cases, calibration is used to meet requirements such as those specified in Federal Aviation Regulation Part 25. Several methods are used for in-flight pitot-static calibration including tower fly-by, pacer aircraft, and trailing cone methods. In the 1990 s, the introduction of satellite-based positioning systems to the civilian market enabled new inflight calibration methods based on accurate ground speed measurements provided by Global Positioning Systems (GPS). Use of GPS for airspeed calibration has many advantages such as accuracy, ease of portability (e.g. hand-held) and the flexibility of operating in airspace without the limitations of test range boundaries or ground telemetry support. The current research was motivated by the need for a rapid and statistically accurate method for in-flight calibration of pitot-static systems for remotely piloted, dynamically-scaled research aircraft. Current calibration methods were deemed not practical for this application because of confined test range size and limited flight time available for each sortie. A method was developed that uses high data rate measurements of static and total pressure, and GPSbased ground speed measurements to compute the pressure errors over a range of airspeed. The novel application of this approach is the use of system identification methods that rapidly compute optimal pressure error models with defined confidence intervals in nearreal time. This method has been demonstrated in flight tests and has shown 2- bounds of approximately 0.2 kts with an order of magnitude reduction in test time over other methods. As part of this experiment, a unique database of wind measurements was acquired concurrently with the flight experiments, for the purpose of experimental validation of the optimization method. This paper describes the GPS-based pitot-static calibration method developed for the AirSTAR research test-bed operated as part of the Integrated Resilient Aircraft Controls (IRAC) project in the NASA Aviation Safety Program (AvSP). A description of the method will be provided and results from recent flight tests will be shown to illustrate the performance and advantages of this approach. Discussion of maneuver requirements and data reduction will be included as well as potential applications.

Foster, John V.↗
NASA NTRS2016

Experimental, Numerical, and Analytical Slosh Dynamics of Water and Liquid Nitrogen in a Spherical Tank

Understanding, predicting, and controlling fluid slosh dynamics is critical to safety and improving performance of space missions when a significant percentage of the spacecraft's mass is a liquid. Computational fluid dynamics simulations can be used to predict the dynamics of slosh, but these programs require extensive validation. Many experimental and numerical studies of water slosh have been conducted. However, slosh data for cryogenic liquids is lacking. Water and cryogenic liquid nitrogen are used in various ground-based tests with a spherical tank to characterize damping, slosh mode frequencies, and slosh forces. A single ring baffle is installed in the tank for some of the tests. Analytical models for slosh modes, slosh forces, and baffle damping are constructed based on prior work. Select experiments are simulated using a commercial CFD software, and the numerical results are compared to the analytical and experimental results for the purposes of validation and methodology-improvement.

slosh↗
NASA NTRS1958

Experimental Study of Ballistic-Missile Base Heating with Operating Rocket

A rocket of the 1000-pound-thrust class using liquid oxygen and JP-4 fuel as propellant was installed in the Lewis 8- by 6-foot tunnel to permit a controlled study of some of the factors affecting the heating of a rocket-missile base. Temperatures measured in the base region are presented from findings of three motor extension lengths relative to the base. Data are also presented for two combustion efficiency levels in the rocket motor. Temperature as high as 1200 F was measured in the base region because of the ignition of burnable rocket gases. combustibles that are dumped into the base by accessories seriously aggravate the base-burning temperature rise.

BALLISTIC MISSILE↗
NASA NTRS2002

Development and Flight Demonstration of a HUMS-Based Helicopter Limit Cueing (HLC) System

A prototype helicopter limit cueing (HLC) system was designed, installed, and evaluated in flight test in early 2002. This paper describes the design, cueing methodology, and interim flight test results of this project. The system described in this paper used available Health and Usage Monitoring System (HUMS) parameters and a simple and cost-effective mechanical spring/electric motor combination to achieve a tactile cue that warned the pilot of impending exceedences of the transmission torque limit. Three high-workload maneuvers were used to evaluate the prototype HLC system. Results indicate that with an appropriate design, inadvertent over-torque events could be eliminated with a HLC system while reducing pilot workload.

Augustin, M.↗
NASA NTRS2004

Electromagnetic Detection of Fatigue Cracks under Protruding Head Ferromagnetic Fasteners

The detection of fatigue cracks under installed fasteners has been a major goal of the aging aircraft NDE community. The Sliding Probe, Magneto-Optic Imager, Rotating Self-Nulling Probe, Low Frequency Eddy Current Array, and Eddyscan systems are among the instruments developed for this inspection. It has been verified that the detection of fatigue cracks under flush head aluminum and titanium fasteners can be accomplished with a high resolution by the above techniques. The detection of fatigue cracks under ferromagnetic and protruding head fasteners, however, has been found to be much more difficult. For the present work, the inspection for fatigue cracks under SAE 4340 Steel Hi-Lok fasteners is explored. Modifications to the Rotating Self-Nulling Eddy Current Probe System are presented which enable the detection of fatigue cracks hidden under the protruding head of the ferromagnetic fastener. Inspection results for samples with varying length EDM notches are shown, as well as a comparison between the signature from an EDM notch and an actual fatigue crack. Finite Element Modeling is used to investigate the effect of the ferromagnetic fastener on the induced eddy current distribution in order to help explain the detection characteristics of the system. This paper will also introduce a modification to the Rotating Probe System designed specifically for the detection of deeply buried flaws in multilayer conductors. The design change incorporates a giant magnetoresistive (GMR) sensor as the pickup device to improve the low frequency performance of the probe. The flaw detection capabilities of the GMR based Self- Nulling Probe are presented along with the status of the GMR based Rotating Probe System for detection of deeply buried flaws under installed fasteners.

Wincheski, Buzz↗
NASA NTRS2018

Analytical Performance, Loads, and Aeroelastic Stability of a Full-Scale Isolated Proprotor

The prediction of the performance and loads of a full-scale isolated proprotor and the calculation of whirl flutter stability of the rotor installed in a wind tunnel are considered in this study. The comprehensive analysis CAMRAD II is used. The test article is a research proprotor based on the Bell 609 rotor and the wind tunnel test apparatus is the newly developed Tiltrotor Test Rig (TTR) installed in the USAF NFAC 40- by 80-Foot Wind Tunnel. The performance and loads predictions and the stability calculations cover the following operating conditions: hover, cruise, conversion, and helicopter mode. These pre-test analytical results are being obtained to identify test operating limits, ensure a safe wind tunnel test and predict test results. Eventually, the goal is to perform a correlation study, identify shortfalls in the analytical model and introduce improvements to the analytical model. Performance and loads test results to date show that rotor torque (and yoke lag moment) may limit the test envelope. Shake test data based stability analysis shows that the TTR/609 is solidly stable within the test envelope.

Proprotor↗