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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

X-rays from an auroral substorm at altitudes of 60-80 km and 15-20 km

A technique for the measurement of high altitude X-rays associated with auroral events is described. The instrument package is boosted to the lower D region by a rocket and descends slowly by parachute. This arrangement facilitates coordination with the launching of other rocket probes during events of interest. A flight on Feb. 2, 1973 from the Churchill Research Range provided 17 minutes of X-ray data above 28 km. The flight was made into an intense break-up event and X-ray fluxes were observed during two episodes of the explosive phase. The reduction of auroral absorption during the later phases of the event suggests precipitation of energetic electrons unaccompanied by the lower energy precipitation responsible for the absorption earlier in the substorm.

Sheldon, W. R.↗
NASA NTRS1974

Plasma and energetic particles in the magnetotail at 60 earth radii

Particle measurements made by the lunar-orbiting Apollo subsatellites have shown that electron energy spectra in the range 0.55-320 keV in the high-latitude magnetotail often fit a power law with an exponent of -3 and a flux at .5 keV of 200,000 to 700,000 el/sq cm s sr keV. In the magnetosheath, electron energy spectra are similar to the high-latitude magnetotail spectra. In the plasma sheet, electron energy spectra often fit the high-energy tail of a Maxwellian distribution with Eo of about 200-500 eV. During times of substorms a number of cases where the plasma sheet appears to thin at onset have been observed. In addition, cases of plasma sheet expansion at onset have also been observed.

Chase, L. M.↗
NASA NTRS1975

Dawn-dusk magnetosheath plasma asymmetries at 60 earth radii

A study of data from the Apollo lunar surface suprathermal ion detector experiment (Side) package shows that plasma flow and energy parameters in the dusk magnetosheath are much better correlated with geomagnetic activity than those in the dawn magnetosheath. This result is in agreement with a dawn-dusk asymmetry in the magnetosheath magnetic field and in the bow shock configuration. The different orientations between the mean interplanetary magnetic field direction and the shock normal for the magnetosheaths suggest an explanation of the difference in the plasma parameters on the two sides.

Fenner, M. A.↗
NASA NTRS1975

Poppet valve control of throat stability bypass to increase stable airflow range of a Mach 2.5. inlet with 60 percent internal contraction

The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. System variations included several stability bypass entrance configurations. Poppet valves controlled the bypass airflow. The inlet stable airflow range achieved with each configuration was determined for both steady state conditions and internal pulse transients. Results are compared with those obtained without a stability bypass system. Transient results were also obtained for the inlet with a choke point at the diffuser exit and for the inlet with large and small stability bypass plenum volumes. Poppet valves at the stability bypass exit provided the inlet with a stable airflow range of 20 percent or greater at all static and transient conditions.

Mitchell, G. A.↗
NASA NTRS1976

Results of heat transfer tests of a 0.0175-scale space shuttle vehicle 5 model (60-OTS) in the NASA-Ames Research Center 3.5-foot hypersonic wind tunnel (test IH48)

Heat transfer data are presented for a .0175-scale model of the Rockwell International Space Shuttle Vehicle 5. The primary purpose of these tests was to obtain aerodynamic interference heating data on the external tank in the tank alone, second-, and first-stage configurations. Data were also obtained on the Orbiter and solid rocket boosters. Nominal Mach Nos. of 5.2 and 5.3 at nominal freestream unit Reynolds numbers of 1.5 and 5.0 million per foot, respectively, were investigated. Photographs of the tested configurations and test equipment are shown.

Dye, W. H.↗
NASA NTRS1976

Kitt Peak 60-cm vacuum telescope

A major new solar-research telescope conceived and built during a time of budget restraint is described. The observation of magnetic and velocity (circulation) field structure on a synoptic basis and with diffraction-limited resolution is the aim. New optical features include the use of oversize mirrors and windows to avoid thermal edge effects and the placement of the coelostat feed outside the vacuum, mainly for economy. The site selected has prevailing winds that clear thermals from these mirrors. Test data in the form of the system MTF and optical transmission, together with examples of full disk magnetograms and photoheliograms, show present performance capability. Measured MTF indicates a response of 0.2 at 1 sec of arc (whereas diffraction-limited response would be about 0.8). System transmission, including the accompanying spectrograph, is only 2-3% (wavelength 0.44-1.1 microns). Thus, both the optical quality and efficiency are subject to improvement.

Livingston, W. C.↗
NASA NTRS1976

Diurnal stratospheric tide in meridional wind, 30 to 60 km, by season

The diurnal component in meridional wind is estimated for each season at twelve rocket stations. Amplitudes and phases are presented as a function of height-latitude or as vertical profiles. Many of the gross features of the tide persist throughout the year, but as they migrate in height and latitude the amplitude or phase at a given location may undergo large changes with season. Longitudinal variations in the diurnal tide are found in the mid-stratosphere, and it is suggested they are coupled with longitudinal variations in the tropospheric temperature structure.

Nastrom, G. D.↗
NASA NTRS1978

Nitronic 60: a new alloy

Report presents test demonstrations of mechanical and stress-corrosion properties at very low temperatures. Included are design details of alloy specimens and test procedures.

Montano, J. W.↗
NASA NTRS1978

From sunlight in space to 60 Hz on earth - The losses along the way

The space-to-ground links for the Solar Power Satellite System are discussed in terms of worst, best, and nominal efficiency used in the development of the preliminary design. An uncertainty analysis of this design illustrates the effect of link efficiency on SPS size and mass. It is shown that a solar power satellite can deliver power to a ground-based utility for 4 to 5 cents per kWh, depending on the efficiency of the solar cells available in 1987. The overall efficiency of converting sunlight in space to electric power delivered to utilities ranged from 3.83% for the worst combination of efficiencies to 9.5% for the best, with a nominal efficiency of 7.12%.

Denman, O. S.↗
NASA NTRS1979

Development of a severe local storm prediction system: A 60-day test of a mesoscale primitive equation model

The progress and problems associated with the dynamical forecast system which was developed to predict severe storms are examined. The meteorological problem of severe convective storm forecasting is reviewed. The cascade hypothesis which forms the theoretical core of the nested grid dynamical numerical modelling system is described. The dynamical and numerical structure of the model used during the 1978 test period is presented and a preliminary description of a proposed multigrid system for future experiments and tests is provided. Six cases from the spring of 1978 are discussed to illustrate the model's performance and its problems. Potential solutions to the problems are examined.

Paine, D. A.↗
NASA NTRS1979

The 60-MW Shuttle Interaction Heating Facility

An arc-heated wind-tunnel system described in the present paper will simulate aerodynamic heating in large-scale tests of the thermal protection system of the Shuttle Orbiter Vehicle during entry. The system provides for large-scale subsystem tests in high-enthalpy streams with boundary layer flows at high Reynolds numbers and for large test-body sizes in stagnation flows. The discussion covers the design concept of the arc-jet systems, the extensive hardware developments of the arc heater to provide reliable operation, and verification and performance measurements of the system's operating envelopes.

W Winovich↗
NASA NTRS1981

Engine condition monitoring: CF6 family 60's through the 80's

The on condition program is described in terms of its effectiveness as a maintenance tool both at the line station as well as at home base by the early detection of engine faults, erroneous instrumentation signals and by verification of engine health. The system encompasses all known methods from manual procedures to the fully automated airborne integrated data system.

Kent, H. J.↗