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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 163 records · Page 9
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NASA NTRS1987

A correlation between the IRAS infrared cirrus at 60 or 100 microns and neutral atomic hydrogen in the outer galaxy

A linear correlation was found between the infrared cirrus at 100 or 60 microns and neutral atomic hydrogen near the galactic plane. Infrared Astronomy Satellite (IRAS) Sky Brightness images were compared to the 0.5 deg resolution Weaver-Williams HI survey in two regions of the outer Galaxy near l = 125 deg and l = 215 deg. The dust temperature inferred is nearly uniform and in reasonable agreement with theoretical predictions of thermal dust emission.

Terebey, Susan↗
NASA NTRS1987

Spatial deconvolution of IRAS galaxies at 60 UM

Using IRAS in a slow scan observing mode to increase the spatial sampling rate and a deconvolution analysis to increase the spatial resolution, several bright galaxies were resolved at 60 micron. Preliminary results for M 82, NGC 1068, NGC 3079 and NGC 2623 show partially resolved emission from 10 to 26 arcsec., full width at half maximum, and extended emission from 30 to 90 arcsec. from the center. In addition, the interacting system, Arp 82, along with Mark 231 and Arp 220 were studied using the program ADDSCAN to average all available survey mode observations. The Arp 82 system is well resolved after deconvolution and its brighter component is extended; the two most luminous objects are not resolved with an upper limit of 15 arcsec. for Arp 220.

Low, Frank J.↗
NASA NTRS1986

The 1984 solar oscillation program of the Mt. Wilson 60-foot tower

The instrumentation, data, and preliminary results from the summer, 1984, solar oscillation observing program which was carried out using the 60-foot tower telescope of the Mt. Wilson Observatory are described. This program was carried out with a dedicated solar oscillation observing system and obtained full-disk Dopplergrams every 40 seconds for up to 11 hours per day. Between June and September, 1984, observations were obtained with a Na magneto-optical filter on 90 different days. The data analysis has progressed to the point that spherical harmonic filter functions were employed to generate a few one-dimensional power spectra from a single day's observations.

Rhodes, Edward J., Jr.↗
NASA NTRS1986

A comparison of three types of pulse tube refrigerators - New methods for reaching 60 K

The three types of pulse tube refrigerator, namely the resonant, basic, and orifice designs, are compared with each other and with such common refrigerators as the Joule-Thomson and Stirling types, using an apparatus able to measure their intrinsic behavior from 30 to 300 K. Orifice pulse tubes are found capable of reaching 60 K temperature drops in a single stage. Additional advantages of the type are (1) a single, room-temperature moving part, (2) the use of moderate pressures and pressure ratios, (3) good intrinsic efficiency, and (4) the ability to operate several stages from the same pressure wave generator. The low refrigeration rate/unit mass flow means, however, that better regenerator units are required.

Radebaugh, Ray↗
NASA NTRS1988

Use of diphosphonates to correct disorders in calcium metabolism and mineral composition of bone tissue with 60-day hypokinesia in rats

Compounds of the diphosphonate group suppress bone resorption and bone tissue metabolism, from which it was assumed that they can be used for the prevention of osteoporosis and disorders of calcium homeostasis in humans during space flight. Two compounds of this group were used for preventive purposes in 60 day hypokinesia in rats. The results showed that diphosphonates have a marked effect on calcium metabolism and the condition of the bone tissues under conditions of long term hypokinesia: they reduce the content of ionized calcium in blood, delay the loss of calcium and phosphorus by the bone tissue, and to a considerable degree prevent reduction of bone density. This confirms the possibility of using compounds of this group for correcting and preventing changes of bone tissue and mineral metabolism during long term hypokinesia.

Morukov, B. V.↗
NASA NTRS1988

A 60-meter erectable assembly concept for a control of flexible structures flight experiment

A flight experiment which proposes to use a 60-m deployable/retractable truss beam attached to the Space Shuttle to study dynamic characterization and control of flexible structures is being studied by NASA. The concept requires a relatively complex mechanism for deploying and retracting the truss on-orbit. Development of such a mechanism having a high degree of reliability will be expensive. An alternative method for constructing the truss is discussed requiring no new technology development or complex mechanisms and has already been demonstrated on-orbit. The alternative method proposes an erectable truss beam which can be assembled by two astronauts in EVA. The EVA crew would have to manually assemble the beam from 468 struts and 165 nodes, and install 7 instrumentation platforms with signal and power cabling. The predicted assembly time is 3 hr and 23 min. The structure would also have to be disassembled and restowed following testing, thus 2 EVA days would be required. To allow 25 hr for data collection (probably a bare minimum to accomplish meaningful tests), current Shuttle operations policy dictates a 9-day mission. The design, assembly procedure and issues associated with the alternative concept are discussed.

Watson, Judith J.↗
NASA NTRS1988

A low speed wind tunnel investigation of Reynolds number effects on a 60-deg swept wing configuration with leading and trailing edge flaps

A low-speed wind tunnel test was performed to investigate Reynolds number effects on the aerodynamic characteristics of a supersonic cruise wing concept model with a 60-deg swept wing incorporating leading-edge and trailing-edge flap deflections. The Reynolds number ranged from 0.3 to 1.6 x 10 to the 6th, and corresponding Mach numbers from .05 to 0.3. The objective was to define a threshold Reynolds number above which the flap aerodynamics basically remained unchanged, and also to generate a data base useful for validating theoretical predictions for the Reynolds number effects on flap performance. This report documents the test procedures used and the basic data acquired in the investigation.

Rao, Dhanvada M.↗
NASA NTRS1988

A full-potential theory analysis of the supersonic aerodynamics of a 60-deg delta wing-body configuration

Experimental spanwise pressure distributions for a 60-deg delta wing/body of approximate fineness ratio 7.6 have been obtained and compared to predictions using full-potential theory. Analysis was performed at Mach 1.6 for angles of attack in the range 0.8 to 10 deg, and for Mach numbers ranging from 1.4 to 1.8 at lift coefficients 0.3 and 0.4. The intent of the study was to examine an attached flow approach for maneuver wing design in the presence of a fuselage. For the Mach number, angle-of-attack conditions considered, the full-potential theory accurately modeled the pressure distributions provided the flow remained attached. By combining the full-potential theory results with an empirical shock-induced separation criterion, it was found that the onset of shock-induced separation can be predicted. The investigation showed that, if an attached-flow approach is used with an empirical method of indicating shock-induced separation, the full-potential method is capable of being used as an effective tool for designing maneuver wings.

Rose, O. C.↗
NASA NTRS1988

Shuttle high resolution accelerometer package experiment results - Atmospheric density measurements between 60-160 km

Indirect or inferred values of atmospheric density encountered by the Shuttle Orbiter during reentry have been calculated from acceleration measurements made by the High Resolution Accelerometer Package (HiRAP) and the Orbiter Inertial Measurement Unit (IMU) liner accelerometers. The atmospheric density data developed from this study represent a significant gain with respect to the body of data collected to date by various techniques in the altitude range of 60 to 160 km. The data are unique in that they cover a very wide horizontal range during each flight and provide insight into the actual density variations encountered along the reentry flight path. The data, which were collected over about 3 years, are also characterized by variations in solar activity, geomagnetic index, and local solar time. Comparison of the flight-derived densities with various atmospheric models have been made, and analyses have attempted to characterize the data and to show correlation with selected physical variables.

Blanchard, R. C.↗
NASA NTRS1987

Estimates of the solar internal angular velocity obtained with the Mt. Wilson 60-foot solar tower

Estimates are obtained of the solar internal angular velocity from measurements of the frequency splittings of p-mode oscillations. A 16-day time series of full-disk Dopplergrams obtained during July and August 1984 at the 60-foot tower telescope of the Mt. Wilson Observatory is analyzed. Power spectra were computed for all of the zonal, tesseral, and sectoral p-modes from l = 0 to 89 and for all of the sectoral p-modes from l = 90 to 200. A mean power spectrum was calculated for each degree up to 89. The frequency differences of all of the different nonzonal modes were calculated for these mean power spectra.

Rhodes, Edward J., Jr.↗
NASA NTRS1989

Design of a 60 GHz beam waveguide antenna positioner

A development model antenna positioner mechanism with an integral 60 GHz radio frequency beam waveguide is discussed. The system features a 2-ft diameter carbon-fiber reinforced epoxy antenna reflector and support structure, and a 2-degree-of-freedom elevation over azimuth mechanism providing hemispherical field of view. Emphasis is placed on the constraints imposed on the mechanism by the radio frequency subsystems and how they impacted the mechanical configuration.

Emerick, Kenneth S.↗
NASA NTRS1988

Development of a 75-watt 60-GHz traveling-wave tube for intersatellite communications

This program covers the initial design and development of a 75 watt, 60 GHz traveling-wave tube for intersatellite communications. The objective frequency band was 59 to 64 GHz, with a minimum tube gain of 35 dB. The objective overall efficiency at saturation was 40 percent. The tube, designated the 961H, used a coupled-cavity interaction circuit with periodic permanent magnet beam focusing to minimize the weight. For efficiency enhancement, it incorporated a four-stage depressed collector capable of radiation cooling in space. The electron gun had a low-temperature (type-M) cathode and an isolated anode. Two tubes were built and tested; one feasibility model with a single-stage collector and one experimental model that incorporated the multistage collector.

Rousseau, A. L.↗
NASA NTRS1988

Initial high-degree p-mode frequency splittings from the 1988 Mt. Wilson 60-foot Tower Solar Oscillation Program

The initial frequency splitting results of solar p-mode oscillations obtained from the 1988 helioseismology program at the Mt. Wilson Observatory are presented. The frequency splittings correspond to the rotational splittings of sectoral harmonics which range in degree between 10 and 598. They were obtained from a cross-correlation analysis of the prograde and retrograde portions of a two-dimensional (t - v) power spectrum. This power spectrum was computed from an eight-hour sequence of full-disk Dopplergrams obtained on July 2, 1988, at the 60-foot tower telescope with a Na magneto-optical filter and a 1024x1024 pixel CCD camera. These frequency splittings have an inherently larger scatter than did the splittings obtained from earlier 16-day power spectra. These splittings are consistent with an internal solar rotational velocity which is independent of radius along the equatorial plane. The normalized frequency splittings averaged 449 + or - 3 nHz, a value which is very close to the observed equatorial rotation rate of the photospheric gas of 451.7 nHz.

Rhodes, Edward J., Jr.↗
NASA NTRS1989

Photoelectric observations of asteroids 3, 24, 60, 261, and 863

Observations of the five asteroids designated 3 Juno, 24 Themis, 60 Echo, 261 Prymo, and 863 Benkoela over the 1978-1984 period have been subjected to Fourier analysis to obtain composite lightcurves. The method yields a rotation-period value, mean absolute magnitudes for each night of observation, and Fourier coefficients that define composite-lightcurve shape, with formal error estimates for all quantities. The first three of the asteroids listed exhibit significant variation in surface albedo.

Harris, A. W.↗
NASA NTRS1960

Experimental Determination of the Effects of Frequency and Amplitude of Oscillation on the Roll-Stability Derivatives for a 60 Degree Delta-Wing Airplane Model

A 60' delta-wing airplane model was oscillated in roll for several frequencies and amplitudes of oscillation to determine the effects of the oscillatory motion on the roll-stability derivatives for the model. The derivatives were measured at a Reynolds number of 1,600,000 for the wing alone, the wing-fuselage combination, and the complete model which included a triangular-plan-form vertical tail. Both rolling and yawing moments due to rolling velocity exhibited large frequency effects for angles of attack higher than 16 degrees. Variations in these derivatives were measured for the lowest frequencies of oscillation; as the frequency increased, the derivatives because more nearly linear with angle of attack. Both velocity derivatives were considerably different at high angles of attack from the corresponding derivatives measured by the steady-state rolling-flow technique. Rolling and yawing moments due to rolling acceleration were measured and similarly found to be highly dependent on frequency at high angles of attack. Some period and time-to-damp computations, which were made to reveal the significance of the acceleration derivatives, indicated that inclusion of the measured derivatives in the equations of motion lengthened the period of the lateral oscillation by 10 percent for a typical delta-wing airplane and increased the time to damp to one-half amplitude by 50 percent.

Fisher, Lewis R.↗
NASA NTRS1989

Pre-pulses: Signature of a trigger process in short (less than 60 secs) solar hard x ray flares

The continuing study of short hard x ray events (less than 60 sec duration) from the Solar Maximum Mission (SMM) Hard X ray Burst Spectrometer (HXRBS) instrument has revealed a unique feature. A well-separated distinctly identifiable, narrow (2 to 6 sec wide) pulse occurs prior to the start of the longer-flare lasting emission activity. Light curves are presented for eight events showing this feature. The pre-pulses show symmetrical rise and fall times. Spectral evolution of the pre-pulses are presented and their evolution compared to that of the main event spectra. It is argued that this feature be the elementary flare burst (de Jager, 1978). These pre-pulses could be a signature of the magnetic reconnection phenomenon discussed by Sturrock et al., (1984).

Deasi, U.↗
NASA NTRS1989

Analysis of the 60-Hz power system at KSC: The Orsino substation

An analysis of the Orsino Substation, a component (50 percent) of the 60-Hertz electric power system at the Kennedy Space Center, is presented. Presented here are separate single-line diagrams of the sixteen feeder circuits to permit easy access to information on the individual feeders for future planning. The load condition of each feeder and load break switch are presented and a heuristic reliability analysis of the system is performed. Information is given about the system fashion useful for decision making purposes. The beauty of it is in the simplified manner by which information about the system can be obtained.

Kalu, Alex O.↗
NASA NTRS1986

NASA 60 GHz intersatellite links definition study. Final Review

Viewgraphs are presented which outline the overall system and component concepts for a 60 GHz intersatellite communications link system (ICLS). The ICLS was designed to augment the capabilities of the current Tracking and Data Relay Satellite System (TDRSS), providing a data rate capacity large enough to accommodate the expected rates for user satellites (USAT's) in the post-1995 timeframe. Two methods of data relay on-board the planned TDAS (Tracking and Data Acquisition) satellites are described. One is an all-baseband system with a bi-directional 2 Gbps data stream; the other is a channelized crosslink system wherein some of the channels are baseband and others are merely frequency translated before re-transmission. The general system and technology design drivers are outlined along with the acquisition architecture design. Descriptions of the TDAS antenna, transmitter, receiver, and mechanical hardware are presented.

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