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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 1,567 records · Page 87
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Aerodynamic Performance of a 0.27-Scale Model of an AH-64 Helicopter with Baseline and Alternate Rotor Blade Sets

Performance of a 27 percent scale model rotor designed for the AH-64 helicopter (alternate rotor) was measured in hover and forward flight and compared against and AH-64 baseline rotor model. Thrust, rotor tip Mach number, advance ratio, and ground proximity were varied. In hover, at a nominal thrust coefficient of 0.0064, the power savings was about 6.4 percent for the alternate rotor compared to the baseline. The corresponding thrust increase at this condition was approx. 4.5 percent which represents an equivalent full scale increase in lift capability of about 660 lbs. Comparable results were noted in forward flight except for the high thrust, high speed cases investigated where the baseline rotor was slightly superior. Reduced performance at the higher thrusts and speeds was likely due to Reynolds number effects and blade elasticity differences.

Kelley, Henry L.↗
NASA NTRS1990

Flight set 360L001 (STS-26) igniter, post flight

Space Transportation System (STS-26) was launched from KSC pad 39B. Two of the Redesigned Solid Rocket Motors (RSRM) were part of the launch system and are designated RSRM-1A and RSRM-1B. Each of these motors were initiated by an 1U75164 igniter. The post flight condition of the igniters and associated components is documented. The overall performance of the igniter components was excellent. No damage or heat affected areas were noted. The sealing elements of the igniter functioned as expected with no evidence of erosion or blowby. The thermal protection system protected all areas adequately. No excessive erosion was noted. Corrosion was found in the special bolt holes in the igniter chamber. The corrosion will not affect refurbishment of the chamber. Beginning with flight 5 grease has been added to the chamber holes to prevent this erosion.

Hale, Elgie J.↗
NASA NTRS1990

Flight motor set 360L001 (STS-26R). Volume 1: System overview, revision A

The NASA space shuttle flight STS-26R, launched at 11:37.00.009 am, EDT on 29 Sep. 1988, used the redesigned solid rocket motors (RSRM) 360L001A and 360L001B. Evaluation of the ground environment instrumentation (GEI) data recorded prior to flight showed no launch commit criteria violations; that the field joint heater and aft skirt thermal conditioning systems performed adequately; and that the GEI data showed good agreement with thermal model predictions. Evaluation of the developmental flight instrumentation (DFI) revealed excellent agreement with both the predicted and required ballistic specifications. All parameters were well within the GEI specification requirements including propellant burn rates, specific impulse values, and thrust imbalance. Recorded strain values also indicated satisfactory radial growth and stress levels, as well as verification of adequate safety factors. Postflight inspection of the insulation, seals, case, and nozzles showed overall excellent performance. Some thermal DFI protective cork was missing, and inoperative field joint vent valves on the thermal protection cork allowed water entry into the field joints upon splashdown. Evaluation of these anomalies, as well as complete evaluation of all Redesigned Solid Rocket Motor components, is contained.

Garecht, Diane M.↗
NASA NTRS1990

Flight set 360H005 (STS-28) seals, volume 4

The performance is assessed of the 360H005, Fifth flight, Redesigned Solid Rocket Motors (RSMR) in respect to joint sealing issues as seen from post flight inspection of the seals and sealing surfaces. The factory joint disassembly inspections have resumed for 360H005. The new factory joint grease application is in effect and now can be assessed during the disassembly process. The RSRM is illustrated consisting of capture feature field joints as is the J-joint insulation configuration. The nozzle-to-case joint design is also illustrated, which includes 100, 7/8 inch radial bolts in conjunction with a wiper O-ring and modified insulation design. The ignition system seals and a cross section of the igniter are illustrated. The configuration of all the internal nozzle joints are also shown. The postflight inspection of both motors showed the seal components to be in excellent condition except for the indentation found on the inner primary seal of the right hand inner igniter gasket, aft face. Detailed inspection results, and inspections performed by the O-ring Inspection Team are presented.

Curry, Jeffrey T.↗
NASA NTRS1990

Upper limit set for level of lightning activity on Titan

Because optically thick cloud and haze layers prevent lightning detection at optical wavelength on Titan, a search was conducted for lightning-radiated signals (spherics) at radio wavelengths using the planetary radioastronomy instrument aboard Voyager 1. Given the maximum ionosphere density of about 3000/cu cm, lightning spherics should be detectable above an observing frequency of 500 kHz. Since no evidence for spherics is found, an upper limit to the total energy per flash in Titan lightning of about 10 to the 6th J, or about 1000 times weaker than that of typical terrestrial lightning, is inferred.

Desch, M. D.↗
NASA NTRS1989

An expert system for setting time steps in dynamic finite element programs

An expert system, ETUDES - Expert Time integration control Using Deep and Surface Knowledge System, which addresses the determination of the timestep for time integration of linear structural dynamic equations is described. This timestep may also be applicable for a moderately nonlinear simulation of the same structure. The program also determines whether an explicit or implicit method is most efficient for the particular simulation. A production rule programming system written in OPS5 is used for the implementation of this prototype expert system. Issues relating to the expert system architecture for this application, such as knowledge representation and structure, as well as domain knowledge are discussed. The prototype is evaluated by measuring its performance in various benchmark model problems.

Ramirez, Martin R.↗
NASA NTRS1990

Geologic setting of diverse volcanic materials in northern Elysium Planitia, Mars

Geologic mapping of high-resolution (30-50 m/pixel) Viking Orbiter images of northern Elysium Planitia has identified seven sites where current problems in martian volcanology, chronology, and stratigraphy can be resolved. These sites, which are discussed in the context of a potential Mars rover/sample return mission, would permit the following investigations: (1) the dating of Lower Amazonian lava flows from Elysium Mons (thereby providing absolute calibration for global crater size/frequency relative chronologies, (2) the petrologic investigation of long run-out lava flows, (3) the geologic interpretation of materials that may either be lava flows or lahar deposits, (4) the analysis of materials believed to be ash deposits produced by explosive eruptions of Hecates Tholus, and (5) the investigation of the stratigraphy of fractured terrain along the boundary between northern Elysium Planitia and southern Utopia Planitia.

Mouginis-Mark, P. J.↗
NASA NTRS1990

A comparison of two major earth radiation budget data sets

Temporally overlapping data from earth-radiation-budget instruments on the Nimbus-7, ERBS, and NOAA-9 satellites during 1984-1986 are compiled in extensive tables and graphs and analyzed comparatively. It is found that Nimbus-7 top-of-the-atmosphere wide-FOV short-wave measurements are about 2.5 percent higher than those by the ERBS instruments, and that Nimbus-7 total-spectrum measurements are about 1 percent higher than ERBS measurements near noon but 1 percent lower near midnight. The combined NOAA-9/ERBS scanner data products are shown to agree with the Nimbus-7 global averages and the NOAA-9/ERBS wide-FOV products to within 0.16 and 0.17 percent, respectively, in outgoing longwave radiation and to within 0.03 percent and 3.55 percent in albedo.

Kyle, H. Lee↗
NASA NTRS1990

A study of the Baldwin effect in the IUE data set

The paper investigates the controversial relation between the continuum luminosity and the C IV 1550 emission-line strength in the spectra of quasars, commonly referred to as the Baldwin effect, as a possible indicator of absolute luminosity. It is concluded that the Baldwin effect does represent a physical correlation between the continuum and the C IV 1550 equivalent width rather than a consequence of selection effects. In addition to the C IV results, a similar relation is found for the Lyman-alpha emission line.

Kinney, A. L.↗
NASA NTRS1990

Flight motor set 36OH005 (STS-28R). Volume 5: (Nozzle component)

A review of the performance and post flight condition of the STS-28 redesigned solid rocket motor (RSRM) nozzles is presented in this document. Applicable discrepancy reports (DR's) and process departures (PD's) are presented in section 5.0. The nozzle component program team (NCPT) performance evaluation and the redesign program review board (RPRB) assessment is included in section 6.0. The STS-28 nozzle assemblies were flown on the RSRM fifth flight (Space Shuttle Columbia). The nozzles were a partially submerged convergent/divergent movable design with an aft pivot point flexible bearing. The nozzle assemblies incorporated the following features: (1) RSRM forward exit cone with snubber assembly; (2) RSRM fixed housing; (3) structural backup outer boot ring (OBR); (4) RSRM cowl ring; (5) RSRM nose inlet assembly; (6) RSRM throat assembly; (7) RSRM forward nose and aft inlet ring; (8) RSRM aft exit cone assembly with linear-shaped charge (LSC); (9) RTV backfill in joints 1, 3, and 4; (10) use of EA913 NA adhesive in place of EA913; (11) redesigned nozzle plug; and (12) carbon cloth phenolic (CCP) with 750 ppm sodium content. The RSRM fifth flight test objectives are as follows: (1) verify that flexible bearing seals operate within the specified temperature range; (2) verify that flexible bearing maintained a positive gas seal between its internal components; (3) inspect flexible bearing for damage due to water impact; (4) verify performance of the nozzle liner; (5) verify that nozzle parts are reusable; (6) verify through flight demonstration and a postflight inspection that the flexible bearing is reusable; (7) verify by inspection the remaining nozzle ablative thicknesses; and (8) verify the nozzle performance margins of safety.

Smith, Dan M., Jr.↗
NASA NTRS1990

Calibration of long term satellite ozone data sets using the space shuttle

Trends in atmospheric ozone continue to be an environmental concern. Drifts in satellite observations are the major obstacle in the detection of changes in global ozone over the long term. Careful re-analysis of satellite ozone data along with groundbased observations have more or less corroborated photochemical models which predict ozone depletion. However, there remains the margin of error in the observations that is as large as the trend itself. The National Plan for Stratospheric Monitoring calls for monitoring global ozone for at lease the next ten years employing the NOAA polar orbiting satellites. Ozone observations will be made with the Solar Backscatter Ultraviolet Spectral Radiometer Mod 2 (SBUV/2) which ia a refinement of the SBUV instrument flying on NASA's Nimbus-7 satellite. The first instrument in the operational series began taking data from the NOAA-9 spacecraft in February 1985. A second instrument was launched on NOAA-11 in September 1988. Both continue to operate. Earlier attempts to calibrate satellite data relied on comparisons with ground based observations. However, differences in instrumental techniques severely complicated these efforts. This problem will be over come by regular flights, about once per year, of the Shuttle Solar Backscatter Ultraviolet radiometer (SSBUV). The data from the SSBUV instrument will be compared with nearly coincident data taken by the NOAA satellite instruments. This procedure will permit a direct calibration transfer in space, since the two instruments observe the same qualities thereby bypassing the inversion algorithm which converts the observations to ozone amounts.

Hilsenrath, Ernest↗
NASA NTRS1991

Analysis of energy balance models using the ERBE data set

A review of Energy Balance Models is presented. Results from the Outgoing Longwave Radiation parameterization are discussed. The albedo parameterizations and the consequences of the new parameterizations are examined.

Graves, Charles E.↗
NASA NTRS1989

Flight motor set 360T004 (STS-30R). Volume 1: System overview

The fourth NASA space shuttle flight incorporating redesigned solid rocket motors began on 4 May 1989. The flight motors were designated 360Q004A (left-hand) and 360H004B (right-hand); the mission was designated STS-30R. Overall engine performance was excellent. The low sample rate data that was available showed exceptional propulsion performance. All ballistic and mass property parameters closely matched the predicted values and were well within the required contract end item specification levels that could be assessed. No strain, vibration, or aft skirt heating environments could be addressed due to developmental flight instrumentation deletion. Infrared readings from the shuttle thermal imager were considered very good when compared with ground environment instrumentation readings taken during both the aborted and the actual countdowns. However, hand-held infrared gun reading/ground environment instrumentation comparisons were considered poor during both countdowns, with the exception of the T - 3 hour timeframe during the actual launch. Postflight inspection again verified superior performance of the insulation, phenolics, metal parts, and seals. All combustion gas was contained by the insulation in the field and case-to-nozzle joints. Inadequate parachute performance on the left-hand booster caused high splashdown loads, which resulted in a displaced nozzle and factory joint weatherseal unbond anomalies. Recommendations were made concerning improved thermal modeling and instruments. The rationale for these recommendations, the dispositions of all anomalies, and complete result details are given.

Ricks, Glenn A.↗
NASA NTRS1989

Ocean color - Availability of the global data set

The use of satellite observations of ocean color to provide reliable estimates of marine phytoplankton biomass on synoptic scales is examined. An overview is given of the Coastal Zone Color Scanner data processing system. The archiving and distribution of ocean color data are discussed, and NASA-sponsored archive sites are listed.

Feldman, Gene↗
NASA NTRS1990

Differential geometry techniques for sets of nonlinear partial differential equations

An attempt is made to show that the Cartan theory of partial differential equations can be a useful technique for applied mathematics. Techniques for finding consistent subfamilies of solutions that are generically rich and well-posed and for introducing potentials or other usefully consistent auxiliary fields are introduced. An extended sample calculation involving the Korteweg-de Vries equation is given.

Estabrook, Frank B.↗
NASA NTRS1991

Representation of vegetation by continental data sets derived from NOAA-AVHRR data

Images of the normalized difference vegetation index (NDVI) are examined with specific attention given to the effect of spatial scales on the understanding of surface phenomena. A scale variance analysis is conducted on NDVI annual and seasonal images of Africa taken from 1987 NOAA-AVHRR data at spatial scales ranging from 8-512 km. The scales at which spatial variation takes place are determined and the relative magnitude of the variations are considered. Substantial differences are demonstrated, notably an increase in spatial variation with coarsening spatial resolution. Different responses in scale variance as a function of spatial resolution are noted in an analysis of maximum value composites for February and September; the difference is most marked in areas with very seasonal vegetation. The spatial variation at different scales is attributed to different factors, and methods involving the averaging of areas of transition and surface heterogeneity can oversimplify surface conditions. The spatial characteristics and the temporal variability of areas should be considered to accurately apply satellite data to global models.

Justice, C. O.↗