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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 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

A workload model and measures for computer performance evaluation

A generalized workload definition is presented which constructs measurable workloads of unit size from workload elements, called elementary processes. An elementary process makes almost exclusive use of one of the processors, CPU, I/O processor, etc., and is measured by the cost of its execution. Various kinds of user programs can be simulated by quantitative composition of elementary processes into a type. The character of the type is defined by the weights of its elementary processes and its structure by the amount and sequence of transitions between its elementary processes. A set of types is batched to a mix. Mixes of identical cost are considered as equivalent amounts of workload. These formalized descriptions of workloads allow investigators to compare the results of different studies quantitatively. Since workloads of different composition are assigned a unit of cost, these descriptions enable determination of cost effectiveness of different workloads on a machine. Subsequently performance parameters such as throughput rate, gain factor, internal and external delay factors are defined and used to demonstrate the effects of various workload attributes on the performance of a selected large scale computer system.

Kerner, H.↗
NASA NTRS1974

Outer planet mission guidance and navigation for spinning spacecraft

The orbit determination accuracies, maneuver results, and navigation system specification for spinning Pioneer planetary probe missions are analyzed to aid in determining the feasibility of deploying probes into the atmospheres of the outer planets. Radio-only navigation suffices for a direct Saturn mission and the Jupiter flyby of a Jupiter/Uranus mission. Saturn ephemeris errors (1000 km) plus rigid entry constraints at Uranus result in very high velocity requirements (140 m/sec) on the final legs of the Saturn/Uranus and Jupiter/Uranus missions if only Earth-based tracking is employed. The capabilities of a conceptual V-slit sensor are assessed to supplement radio tracking by star/satellite observations. By processing the optical measurements with a batch filter, entry conditions at Uranus can be controlled to acceptable mission-defined levels (+ or - 3 deg) and the Saturn-Uranus leg velocity requirements can be reduced by a factor of 6 (from 139 to 23 m/sec) if nominal specified accuracies of the sensor can be realized.

Paul, C. K.↗
NASA NTRS1979

Energy from aquatic plant wastewater treatment systems

Water hyacinth (Eichhornia crassipes), duckweed (Spirodela sp. and Lemma sp.), water pennywort (Hydrocotyle ranunculoides), and kudzu (Pueraria lobata) were anaerobically fermented using an anaerobic filter technique that reduced the total digestion time from 90 days to an average of 23 days and produced 0.14-0.28 cu m CH4/kg (dry weight) (2.3-4.5 cu ft/lb) from mature filters. The anaerobic filter provided a large surface area for the anaerobic bacteria to establish and maintain an optimum balance of facultative, acid-forming, and methane-producing bacteria. Consequently the efficiency of the process was greatly improved over prior batch fermentations.

Wolverton, B. C.↗
NASA NTRS1980

Automatic technique for accurately locating planet centers in Voyager images

An algorithm has been developed for locating with sub-pixel accuracy planet centers in the Voyager images of the Jovian system based upon automatic recognition of the planet limb. The planet center finder, called FARENC (for far encounter imaging mode), is a single VICAR program operating on IBM 360/65 computer. FARENC is designed to handle images of the order of 800 to 1000 pixels, to operate unaided in a batch environment, and to complete the process reliably in 2 minutes or less. The procedure is outlined step by step and limitations of the algorithm are discussed.

Lorre, J. J.↗
NASA NTRS1981

The effect of data analysis techniques on the interpretation of wide-angle longwave radiation measurements

Three different data analysis techniques - shape factor, parameter estimation, and deconvolution - have been applied to the same set of satellite radiation measurements to determine their effect on the estimated radiation field. The measurements are from a wide-angle, horizon-to-horizon, nadir-pointing sensor. The shape factor technique reduces each measurement to a radiant exitance at the top of the atmosphere by simple division by a constant. The parameter estimation technique processes all measurements together as a batch and defines the radiant exitance as a least-squares fit to the data. The deconvolution technique takes advantage of the fact that spherical harmonics are the eigenfunctions of the measurement operator. All three techniques are derived, and their assumptions, advantages and disadvantages are discussed. Their results are compared globally, zonally, regionally and on a spatial spectrum basis. All three techniques give comparable results for global parameters; however, results on a regional scale were quite different. The standard deviations of the regional differences in radiant exitance varied from 7.4 to 13.5 W/sq m. Of the three techniques, the parameter estimation technique produced the best regional results and is the choice of the author.

Green, R. N.↗
NASA NTRS1988

GOES dynamic propagation of attitude

The spacecraft in the next series of Geostationary Operational Environmental Satellites (GOES-Next) are Earth pointing and have 5-year mission lifetimes. Because gyros can be depended on only for a few years of continuous use, they will be turned off during routine operations. This means attitude must, at times, be determined without benefit of gyros and, often, using only Earth sensor data. To minimize the interruption caused by dumping angular momentum, these spacecraft have been designed to reduce the environmental torque acting on them and incorporate an adjustable solar trim tab for fine adjustment. A new support requirement for GOES-Next is that of setting the solar trim tab. Optimizing its setting requires an estimate of the unbalanced torque on the spacecraft. These two requirements, determining attitude without gyros and estimating the external torque, are addressed by replacing or supplementing the gyro propagation with a dynamic one, that is, one that integrates the rigid body equations of motion. By processing quarter-orbit or longer batches, this approach takes advantage of roll-yaw coupling to observe attitude completely without Sun sensor data. Telemetered momentum wheel speeds are used as observations of the unbalanced external torques. GOES-Next provides a unique opportunity to study dynamic attitude propagation. The geosynchronous altitude and adjustable trim tab minimize the external torque and its uncertainty, making long-term dynamic propagation feasible. This paper presents the equations for dynamic propagation, an analysis of the environmental torques, and an estimate of the accuracies obtainable with the proposed method.

Markley, F. Landis↗
NASA NTRS1989

Estimation and filtering techniques for high-accuracy GPS applications

Techniques for determination of very precise orbits for satellites of the Global Positioning System (GPS) are currently being studied and demonstrated. These techniques can be used to make cm-accurate measurements of station locations relative to the geocenter, monitor earth orientation over timescales of hours, and provide tropospheric and clock delay calibrations during observations made with deep space radio antennas at sites where the GPS receivers have been collocated. For high-earth orbiters, meter-level knowledge of position will be available from GPS, while at low altitudes, sub-decimeter accuracy will be possible. Estimation of satellite orbits and other parameters such as ground station positions is carried out with a multi-satellite batch sequential pseudo-epoch state process noise filter. Both square-root information filtering (SRIF) and UD-factorized covariance filtering formulations are implemented in the software.

Lichten, S. M.↗
NASA NTRS1990

Estimation and filtering for high-precision GPS positioning applications

Estimation of GPS satellite orbits and other parameters for high-accuracy geodetic and tracking applications is carried out with a multi-satellite batch sequential pseudo-epoch state process noise filter. Both square-root information filtering and UD factorized covariance filtering and smoothing formulations are implemented in the software to enhance numerical stability. The filtering algorithms have been arranged to take advantage of sparse matrices and other characteristics of the GPS measurement scenarios. The filter includes unique error evaluation capabilities to assess effects from mismodeling. Process noise plays a key role in the orbit determination for stochastic behavior of transmitter/receiver clocks, atmospheric-induced delay fluctuations, and unmodeled spacecraft accelerations. Present GPS orbit accuracy is better than 1 m, with ground baselines determined simultaneously to relative accuracy of 1.5 parts in 10 to the 8th over several thousand km distance.

Lichten, Stephen M.↗
NASA NTRS2013

Analysis of the Impedance Resonance of Piezoelectric Multi-Fiber Composite Stacks

Multi-Fiber CompositesTM (MFC's) produced by Smart Materials Corp behave essentially like thin planar stacks where each piezoelectric layer is composed of a multitude of fibers. We investigate the suitability of using previously published inversion techniques for the impedance resonances of monolithic co-fired piezoelectric stacks to the MFCTM to determine the complex material constants from the impedance data. The impedance equations examined in this paper are those based on the derivation. The utility of resonance techniques to invert the impedance data to determine the small signal complex material constants are presented for a series of MFC's. The technique was applied to actuators with different geometries and the real coefficients were determined to be similar within changes of the boundary conditions due to change of geometry. The scatter in the imaginary coefficient was found to be larger. The technique was also applied to the same actuator type but manufactured in different batches with some design changes in the non active portion of the actuator and differences in the dielectric and the electromechanical coupling between the two batches were easily measureable. It is interesting to note that strain predicted by small signal impedance analysis is much lower than high field stains. Since the model is based on material properties rather than circuit constants, it could be used for the direct evaluation of specific aging or degradation mechanisms in the actuator as well as batch sorting and adjustment of manufacturing processes.

Multi-fiber composites↗
NASA NTRS2021

Radio Frequency Plasma Synthesis of Boron Nitride Nanotubes (BNNTs) for Structural Applications: Part III

The emergence of commercial quantities of BNNTs facilitates the exploration of structural material applications. BNNT-reinforced composites must exhibit extraordinary mechanical properties in order to justify the cost premium. Prevailing theory indicates that suitable BNNTs must possess an aspect ratio (AR= length/diameter) approaching 10,000 to provide effective discontinuous reinforcement under tensile loading. A survey of commercial products shows that although the quantities are sufficient, lots of uniform morphology are unavailable. Therefore, the opportunity exists to supplement procedures either during synthesis operations or post-synthesis processing in order to deliver homogeneous batches of high AR BNNTs. An assessment of relevant technologies reveals established methods compatible with sorting of BNNTs by physical dimensions, i.e., size and/or shape. Electrostatic fractionation emerges as the leading candidate, with the potential to isolate high-purity, low-defect, high AR product. The adaptation of existing equipment to the handling of fibrous particulate on the nanoscale will be paramount to success. Although currently focused on BNNTs, the concepts outlined may be applied to nanotubes synthesized from any organic or inorganic compounds. This survey sets the stage for delivering reproducible lots of BNNTs that satisfy the dimensional requirements for use in acreage structural materials.

induction plasma, BNNT, aspect ratio, fractionatio↗
NASA NTRS1978

AOIPS - An interactive image processing system

The Atmospheric and Oceanographic Information Processing System (AOIPS) was developed to help applications investigators perform required interactive image data analysis rapidly and to eliminate the inefficiencies and problems associated with batch operation. This paper describes the configuration and processing capabilities of AOIPS and presents unique subsystems for displaying, analyzing, storing, and manipulating digital image data. Applications of AOIPS to research investigations in meteorology and earth resources are featured.

Bracken, P. A.↗
NASA NTRS1977

Image data-processing system for solar astronomy

The paper describes an image data processing system (IDAPS), its hardware/software configuration, and interactive and batch modes of operation for the analysis of the Skylab/Apollo Telescope Mount S056 X-Ray Telescope experiment data. Interactive IDAPS is primarily designed to provide on-line interactive user control of image processing operations for image familiarization, sequence and parameter optimization, and selective feature extraction and analysis. Batch IDAPS follows the normal conventions of card control and data input and output, and is best suited where the desired parameters and sequence of operations are known and when long image-processing times are required. Particular attention is given to the way in which this system has been used in solar astronomy and other investigations. Some recent results obtained by means of IDAPS are presented.

Wilson, R. M.↗
NASA NTRS1998

Effects of Fiber Coating Composition on Mechanical Behavior of Silicon Carbide Fiber-Reinforced Celsian Composites

Celsian matrix composites reinforced with Hi-Nicalon fibers, precoated with a dual layer of BN/SiC by chemical vapor deposition in two separate batches, were fabricated. Mechanical properties of the composites were measured in three-point flexure. Despite supposedly identical processing, the composite panels fabricated with fibers coated in two batches exhibited substantially different mechanical behavior. The first matrix cracking stresses (sigma(sub mc)) of the composites reinforced with fibers coated in batch 1 and batch 2 were 436 and 122 MPa, respectively. This large difference in sigma(sub mc) was attributed to differences in fiber sliding stresses(tau(sub friction)), 121.2+/-48.7 and 10.4+/-3.1 MPa, respectively, for the two composites as determined by the fiber push-in method. Such a large difference in values of tau(sub friction) for the two composites was found to be due to the difference in the compositions of the interface coatings. Scanning Auger microprobe analysis revealed the presence of carbon layers between the fiber and BN, and also between the BN and SiC coatings in the composite showing lower tau(sub friction). This resulted in lower sigma(sub mc) in agreement with the ACK theory. The ultimate strengths of the two composites, 904 and 759 MPa, depended mainly on the fiber volume fraction and were not significantly effected by tau(sub friction) values, as expected. The poor reproducibility of the fiber coating composition between the two batches was judged to be the primary source of the large differences in performance of the two composites.

Bansal, Narottam P.↗
NASA NTRS1980

A description of a system of programs for mathematically processing on unified series (YeS) computers photographic images of the Earth taken from spacecraft

A description of a batch of programs for the YeS-1040 computer combined into an automated system for processing photo (and video) images of the Earth's surface, taken from spacecraft, is presented. Individual programs with the detailed discussion of the algorithmic and programmatic facilities needed by the user are presented. The basic principles for assembling the system, and the control programs are included. The exchange format within whose framework the cataloging of any programs recommended for the system of processing will be activated in the future is displayed.

Zolotukhin, V. G.↗
NASA NTRS2009

A Study on Advanced Lithium-Based Battery Cell Chemistries to Enhance Lunar Exploration Missions

NASA's Exploration Technology Development Program (ETDP) Energy Storage Project conducted an advanced lithium-based battery chemistry feasibility study to determine the best advanced chemistry to develop for the Altair lunar lander and the Extravehicular Activities (EVA) advanced lunar surface spacesuit. These customers require safe, reliable energy storage systems with extremely high specific energy as compared to today's state-of-the-art batteries. Based on customer requirements, the specific energy goals for the development project are 220 watt-hours per kilogram (Wh/kg) delivered at the battery level at 0 degrees Celsius (degrees Celcius) at a C/10 discharge rate. Continuous discharge rates between C/5 and C/2, operation over 0 to 30 degrees C, and 200 cycles are targeted. The team, consisting of members from NASA Glenn Research Center, Johnson Space Center, and Jet Propulsion laboratory, surveyed the literature, compiled information on recent materials developments, and consulted with other battery experts in the community to identify advanced battery materials that might be capable of achieving the desired results with further development. A variety of electrode materials were considered, including layered metal oxides, spinel oxides, and olivine-type cathode materials, and lithium metal, lithium alloy, and silicon-based composite anode materials. lithium-sulfur systems were also considered. Hypothetical cell constructs that combined compatible anode and cathode materials with suitable electrolytes, separators, current collectors, headers, and cell enclosures were modeled. While some of these advanced materials are projected to obtain the desired electrical performance, there are risks that also factored into the decision making process. The risks include uncertainties due to issues such as safety of a system containing some of these materials, ease of scaling-up of large batches of raw materials, adaptability of the materials to processing using established or reasonable cost manufacturing techniques, manufacturability of the materials in dimensions required for integration into battery cells of practical capacities, low Technology Readiness levels (TRl), and the ability to achieve the desired performance by the customer need dates. The advanced cell chemistry options were evaluated with respect to multiple quantitative and qualitative attributes while considering their projected performance at the end of the available development timeframe. Following a rigorous ranking process, a chemistry that combines a lithiated nickel manganese cobalt oxide (lithium NMC) cathode with a silicon-based composite anode was selected as the technology that can offer the best combination of safety, specific energy, energy density, and likelihood of success. Tasks over the next three years will focus on development of electrode materials, compatible electrolytes, and separator materials, and integration of promising components to assess their combined performance in working cells. Cells of the chosen chemistry will be developed to TRl 6 by 2014 and will then be transferred to the customers for infusion into their mission paths.

Reid, Concha↗
NASA NTRSDate not supplied

Microwave Structure Construction Capability Year One Accomplishments

The Microwave Structure Construction Capability (MSCC) element, part of the Moon to Mars Planetary Autonomous Construction Project (MMPACT) was initiated in 2020. MSCC is responsible for creating horizontal and vertical infrastructure on the moon using microwave energy. Microwave energy was selected since it is the only method to volumetrically heat the regolith. All other sintering/melting methods rely on thermal conduction through the very low conductivity surface, resulting in an inefficient process. Advances were achieved in materials characterization and understanding, microwave sintering in vacuum, and microwave design and analyses. Two dielectric property testing systems have been developed at Radiance Technologies and JPL. These will examine dielectric properties at cryogenic temperatures and over a broad frequency range. Permittivity and permeability testing at -60 ̊C in vacuum from 0.05 to 3 GHz has been generated at JPL. Additional modifications will be made to go to -190 ̊C (LN2). Radiance Technologies created a test system to measure dielectric properties at greater than 10 GHz and initiated work on developing a vacuum capable, portable test system to measure dielectric properties of Apollo regolith and simulants from 100 MHz to 18 GHz. These tests are to identify optimal heating frequencies and protocols. During microwave sintering at about 1100 ̊C, volatiles were creating difficulty in achieving a reasonably dense specimen. Due to processing in vacuum and the nature of the lunar regolith, some volatiles and porosity are expected. However, the Earth produced simulants have non-lunar materials in them that create volatiles that aren’t representative of lunar regolith. Therefore, a five month effort was conducted to establish a heat treat method to remove these non-lunar materials. Tests were conducted using TGA mass spectrometry, heating in vacuum and conducting mass spectrometry, dielectric and DTA, Raman, BET, particle size analysis, morphological analysis, carbon and sulfur chemical content determination and microscopy. The process has been scaled-up to 6 kg batch size and undergoing evaluation. A 36 kg batch size is the target for JSC-1A and other limited availability simulants. These calcining protocols will be standard for NASA and beyond. MSCC has also created scalable processes for fabricating synthetic lunar materials. Processes to fabricate Anorthite (plagioclase CaAl2Si2O8), Diopside (pyroxene CaMgSi₂O₆), and Enstatite (pyroxene Mg2Si2O6) have been generated. These materials will enable generation of microwave sintering models to bound various composition ranges anticipated on the Moon, therefore mitigating the need for a precise simulant with respect to location on the Moon. Successful microwave sintering in air using a horn applicator was demonstrated. All previous microwave vacuum sintering in the literature was at small scale and in a contained enclosure thus taking advantage of reflections. This is the first to use a lunar like microwave applicator to sinter ceramic in a bed as it would be done on the Moon. Small scale and inert sintering were conducted to assist in developing protocols with quicker turnaround times than larger scale testing. Testing has anchored thermal analysis predicting heat flow in vacuum during microwave sintering. Thermal conductivity testing was also initiated. Microwave coupling to the regolith has been modeled by multiple organizations and with different software packages. At least six horn designs and applicator configurations for both magnetron and solid state sources are being examined. Optimal simulant container designs for microwaves have also been generated. The power and electronics design for the solid state microwave system has been initiated. Concept designs for a lander based microwave sintering have been evaluated.

microwave↗
NASA NTRS1974

Titanium honeycomb acoustic lining structural and thermal test report

The results are presented of static, fatigue and thermal testing of titanium honeycomb acoustic panels representing the acoustic tailpipe for the Pratt and Whitney Aircraft JT8D Refan engine which is being studied for use on the Boeing 727-200 airplane. Test specimens represented the engine and tailpipe flange joints, the rail to which the thrust reverser is attached and shear specimens of the tailpipe honeycomb. Specimens were made in four different batches with variations in configuration, materials and processes in each. Static strength of all test specimens exceeded the design ultimate load requirements. Fatigue test results confirmed that aluminum brazed titanium, as used in the Refan tailpipe design, meets the fatigue durability objectives. Quality of welding was found to be critical to life, with substandard welding failing prematurely, whereas welding within the process specification exceeded the panel skin life. Initial fatigue testing used short grip length bolts which failed prematurely. These were replaced with longer bolts and subsequent testing demonstrated the required life. Thermal tests indicate that perforated skin acoustic honeycomb has approximately twice the heat transfer of solid skin honeycomb.

Joynes, D.↗
NASA NTRS1975

Use of graphics in the design office at the Military Aircraft Division of the British Aircraft Corporation

The CAD/CAM interactive computer graphics system was described; uses to which it has been put were shown, and current developments of the system were outlined. The system supports batch, time sharing, and fully interactive graphic processing. Engineers using the system may switch between these methods of data processing and problem solving to make the best use of the available resources. It is concluded that the introduction of on-line computing in the form of teletypes, storage tubes, and fully interactive graphics has resulted in large increases in productivity and reduced timescales in the geometric computing, numerical lofting and part programming areas, together with a greater utilization of the system in the technical departments.

Coles, W. A.↗