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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 829 records · Page 46
All sourcesNASA NTRSDOE OSTI
NASA NTRS2004

Generic Hypersonic Inlet Module Analysis

A computational study associated with an internal inlet drag analysis was performed for a generic hypersonic inlet module. The purpose of this study was to determine the feasibility of computing the internal drag force for a generic scramjet engine module using computational methods. The computational study consisted of obtaining two-dimensional (2D) and three-dimensional (3D) computational fluid dynamics (CFD) solutions using the Euler and parabolized Navier-Stokes (PNS) equations. The solution accuracy was assessed by comparisons with experimental pitot pressure data. The CFD analysis indicates that the 3D PNS solutions show the best agreement with experimental pitot pressure data. The internal inlet drag analysis consisted of obtaining drag force predictions based on experimental data and 3D CFD solutions. A comparative assessment of each of the drag prediction methods is made and the sensitivity of CFD drag values to computational procedures is documented. The analysis indicates that the CFD drag predictions are highly sensitive to the computational procedure used.

Cockrell, Chares E., Jr.↗
NASA NTRS1974

Evaluation of localized muscle fatigue using power spectral density analysis of the electromyogram

Surface electromyograms (EMGs) taken from three upper torso muscles during a push-pull task were analyzed by a power spectral density technique to determine the operational feasibility of the technique for identifying changes in the EMGs resulting from muscular fatigue. The EMGs were taken from four subjects under two conditions (1) in shirtsleeves and (2) in a pressurized space suit. This study confirmed that frequency analysis of dynamic muscle activity is capable of providing reliable data for many industrial applications where fatigue may be of practical interest. The results showed significant effects of the pressurized space suit on the pattern of shirtsleeve fatigue responses of the muscles. The data also revealed (1) reliable differences between muscles in fatigue-induced responses to various locations in the reach envelope at which the subjects were required to perform the push-pull exercise and (2) the differential sensitivity of muscles to the various reach positions in terms of fatigue-related shifts in EMG power.

Lafevers, E. V.↗
NASA NTRS1972

Shuttle free-flying teleoperator system experiment definition. Volume 3: program development requirements

The planning data are presented for subsequent phases of free-flying teleoperator program (FFTO) and includes costs, schedules and supporting research and technology activities required to implement the free-flying teleoperator system and associated flight equipment. The purpose of the data presented is to provide NASA with the information needed to continue development of the FFTO and integrate it into the space shuttle program. The planning data describes three major program phases consisting of activities and events scheduled to effect integrated design, development, fabrication and operation of an FFTO system. Phase A, Concept Generation, represents a study effort directed toward generating and evaluating a number of feasible FFTO experiment system concepts. Phase B, Definition, will include preliminary design and supporting analysis of the FFTO, the shuttle based equipment and ground support equipment. Phase C/D, Design, Development and Operations will include detail design of the operational FFTO, its integration into the space shuttle, hardware fabrication and testing, delivery of flight hardware and support of flight operations. Emphasis is placed on the planning for Phases A and B since these studies will be implemented early in the development cycle. Phase C/D planning is more general and subject to refinement during the definition phase.

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NASA NTRS1973

Engineering studies related to geodetic and oceanographic remote sensing using short pulsed techniques

Theoretical basis is presented for a feasibility study of measuring global ocean surface current pattern from satellites and aircraft. The analysis is supported by some preliminary laboratory experiments. Since the ultimate goal is to establish an operational routine for monitoring the global current pattern, a nondisturbing remote sensing device using a laser probe was developed. Detailed construction of the measuring system and the results of some preliminary observations are also presented.

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NASA NTRS1975

Identification and interpretation of tectonic features from Skylab imagery

The author has identified the following significant results. Two alternate models for the extension of the Texas zone through the Mojave Desert block have been developed: (1) along the Pisgah Line, and (2) along the eastern Transverse Ranges; this model suggests a counterclockwise rotation of the Mojave block. Analysis of S190B photographs of the western Mojave Desert provides strong evidence for the feasibility of identifying recent fault breaks.

Abdel-Gawad, M.↗
NASA NTRS1976

Economic analysis of standard interface modules for use with the multi-mission spacecraft, volume 1

A preliminary technical and economic feasibility study was made of the use of Standardized Interstate Modules (SIM) to perform electual interfacing functions that were historically incorporated into sensors. Sensor interface functions that are capable of standardization from the set of missions planned for the NASA Multi-Mission Spacecraft (MMS) in the 1981 to 1985 time period were identified. The cost savings that could be achieved through the replacement of nonstandard sensor interface flight hardware that might be used in these missions with SIM were examined.

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NASA NTRS1980

Comparative thermal analysis of alternate Cryogenic Fluid Management Experiment (CFME) configurations

The Cryogenic Fluid Management Experiment (CFME) was analyzed to assess the feasibility and advisability of deleting the vapor cooled shield (VCS) from the baseline CFME insulation and pressure control system. Two alternate concepts of CFME insulation and pressure control, neither of which incorporated the VCS, were investigated. The first concept employed a thermodynamic vent system (TVS) to throttle the flow through an internal wall mounted heat exchanger (HX) within the pressure vessel to decrease boiloff and pressure rise rate, while the second concept utilized a TVS without an internal heat exchanger. Only the first concept was viable. Its performance was assessed for a seven day mission and found to be satisfactory. It was also concluded that VCS development costs would be greater than for an internal HX installation. Based upon the above comparisons, the HX was recommended as a replacement for the VCS.

Merino, F.↗
NASA NTRS1984

A methodology for collecting valid software engineering data

An effective data collection method for evaluating software development methodologies and for studying the software development process is described. The method uses goal-directed data collection to evaluate methodologies with respect to the claims made for them. Such claims are used as a basis for defining the goals of the data collection, establishing a list of questions of interest to be answered by data analysis, defining a set of data categorization schemes, and designing a data collection form. Feasibility of the data collection methodology was demonstrated by applying it to five different projects in two different environments (other NRL Reports). The application showed that the methodology was both feasible and useful.

Basili, V. R.↗
NASA NTRS1985

Containerless Processing of Glass Forming Melts in Space

The major objectives of this work are: (1) obtain quantitative evidence for the suppression of heterogeneous nucleation/crystallization in containerless melts in micro-g; (2) study melt homogenization in the absence of gravity driven convection; (3) develop the procedures for preparing precursor samples suitable for flight experiments; (4) perform comparative property analysis of glasses melted on Earth and in micro-g; (5) determine the feasibility of preparing glass shells in micro-g for use as laser fusion targets; and (6) assess the operational performance of the single axis acoustic levitator/furnace apparatus for processing multicomponent, glass forming melts in micro-g. Ways of obtaining these goals are discussed.

Day, D. D.↗
NASA NTRS1986

Flight Experiment Demonstration System (FEDS) analysis report

The purpose of the Flight Experiment Demonstration System (FEDS) was to show, in a simulated spacecraft environment, the feasibility of using a microprocessor to automate the onboard orbit determination functions. The software and hardware configuration used to support FEDS during the demonstration and the results of the demonstration are discussed.

Shank, D. E.↗
NASA NTRS1987

Light funnel concentrator panel for solar power

The solar concentrator design concept provides a theoretical concentration efficiency of 96 percent with power-to-weight ratios as high as 50 W/kg. Further, it eliminates the need for fragile reflective coatings and is very tolerant to pointing inaccuracies. The concept differs from conventional reflective mirrors and lens design in that is uses the principle of total internal reflection in order to funnel incident sunlight into a concentrator photovoltaic cell. The feasibility of the light funnel concentrator concept was determined through a balanced approach of analysis, development, and fabrication of prototypes, and testing of components. A three-dimensional optical model of the light funnel concentrator and photovoltaic cell was developed in order to assess the ultimate performance of such systems. In addition, a thermal and structural analysis of a typical unit was made. Techniques of fabricating the light funnel cones, optically coupling them to GaAs concentrator cells, bonding the funnels to GaAs cells, making electrical interconnects, and bonding substrates was explored and a prototype light funnel concentrator unit was fabricated and tested. Testing of the system included measurements of optical concentrating efficiency, optical concentrator to cell coupling efficiency, and electrical efficiency.

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NASA NTRS1988

Cryogenic propulsion for lunar and Mars missions

Future missions to the moon and Mars have been investigated with regard to propulsion system selection. The results of this analysis show that near state-of-the-art LO2/LH2 propulsion technology provides a feasible means of performing lunar missions and trans-Mars injections. In other words, existing cryogenic space engines with certain modifications and product improvements would be suitable for these missions. In addition, present day cryogenic system tankage and structural weights appear to scale reasonably when sizing for large payload and high energy missions such as sending men to Mars.

Redd, Larry↗
NASA NTRS1990

NASA's HITEMP program for UHBR engines

NASA's High Temperature Engine Materials Program (HITEMP) is concerned with the laboratory-scale technology development and feasibility demonstration of high-temperature composite materials, in conjunction with the requisite structural analysis models and test methods for their validation. HITEMP encompasses research on metallic/intermetallic, ceramic, and polymer matrix composites, and is giving attention to high-temperature component composites applicable to future widebody commercial aircraft ultrahigh bypass ratio (UHBR) engines. The UHBR components for which advanced composites are envisioned are fan, compressor, and turbine rotor blades, stator vanes, disks, and shafts, thrust bearings, gearbox bearings and linings, combustor cases and linings, nacelles, and thrust-reversers.

Stephens, Joseph R.↗
NASA NTRS1991

A comparison of airborne wake vortex detection measurements with values predicted from potential theory

An analysis of flight measurements made near a wake vortex was conducted to explore the feasibility of providing a pilot with useful wake avoidance information. The measurements were made with relatively low cost flow and motion sensors on a light airplane flying near the wake vortex of a turboprop airplane weighing approximately 90000 lbs. Algorithms were developed which removed the response of the airplane to control inputs from the total airplane response and produced parameters which were due solely to the flow field of the vortex. These parameters were compared with values predicted by potential theory. The results indicated that the presence of the vortex could be detected by a combination of parameters derived from the simple sensors. However, the location and strength of the vortex cannot be determined without additional and more accurate sensors.

Stewart, Eric C.↗
NASA NTRS1991

Real-time earthquake monitoring: Early warning and rapid response

A panel was established to investigate the subject of real-time earthquake monitoring (RTEM) and suggest recommendations on the feasibility of using a real-time earthquake warning system to mitigate earthquake damage in regions of the United States. The findings of the investigation and the related recommendations are described in this report. A brief review of existing real-time seismic systems is presented with particular emphasis given to the current California seismic networks. Specific applications of a real-time monitoring system are discussed along with issues related to system deployment and technical feasibility. In addition, several non-technical considerations are addressed including cost-benefit analysis, public perceptions, safety, and liability.

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NASA NTRS1999

CFD Predictions of Sonic-Boom Characteristics for Unmodified and Modified SR-71 Configurations

Shaped sonic-boom signatures refer to signatures that look something other than the typical N-waves. Shaped sonic-boom signatures such as "flat-top," "ramp-type," or "hybrid-type" waveforms have been shown to reduce the subjective loudness without requiring reductions in overpressure peaks. The shaping of sonic-boom signatures requires increasing the shock rise time and changes in frequency spectra. So far, a flat-top waveform was shown to be achievable in wind tunnels; however, the influence of long propagation distance and real atmosphere on shaped signatures should be addressed using flight tests. Two different approaches have been proposed for sonic-boom minimization flight tests. The first approach, proposed by Eagle Aerospace, is for a flight test using a modified BQM-34 "FIREBEE" remotely piloted vehicle. The 30-foot long FIREBEE has a steady state flight condition at the Mach number and altitude of interest, and it can be recovered by helicopter from the water. As an alternative approach, a modified SR-71 vehicle has been proposed by the McDonnell Douglas Corporation. Benefits of the SR-71 include its variable geometry supersonic inlets, small cockpit bulge, higher Mach number capabilities, slender design, and longer length (105 foot). The present investigation addresses the sonic-boom analysis for the second vehicle.The objective of the current investigation is to assess the feasibility of a modified SR-71 configuration, with McDonnell Douglas-designed fuselage modifications, intended to produce shaped sonic-boom signatures on the ground. The present study describes the use of a higher-order computational fluid dynamics (CFD) method to predict the sonic-boom characteristics for both unmodified and modified SR-71 configurations. An Euler unstructured grid methodology is used to predict the near-field, three-dimensional pressure patterns generated by both SR-71 models. The computed near-field pressure signatures are extrapolated to specified distances below the aircraft down to impingement on the ground using the code MDBOOM. Comparisons of the near-field pressure signatures with available flight-test data are presented in the current paper.

Fouladi, Kamran↗