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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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NASA NTRS1974

The cosmic ray electron spectrum and its modulation from 1968 through 1972

Over the past five years we have measured the energy spectrum of primary cosmic ray electrons with both a balloon-borne and a satellite absorption spectrometer. All of the balloon flights used identical equipment that was launched each summer from Fort Churchill, Manitoba, Canada. The satellite, OGO-5, has been in an eccentric orbit since March 1968. Together these instruments provide the electron spectrum over a range of energy from 20 MeV to 20 GeV. This wide range and the substantial span of time covered by the measurements permit a detailed study of the solar modulation of electrons. These results are compared with the modulation of the nuclear components as observed by a neutron monitor and interpreted using the cosmic ray transport equation.

Fulks, G.↗
NASA NTRS1974

An investigation of wave-particle interactions and particle dynamics using electron beams injected from sounding rockets

Electrons with energy up to 40 kV have been injected into semi-trapped orbits from sounding rockets at Wallops Island, Virginia, and at Fort Churchill, Manitoba, Canada. By directing the rocket trajectory to have a horizontal component which in direction and speed matched the bounce displacement of the injected electrons, it was possible to detect conjugate echoes at Wallops and possibly at Churchill, and to study the distribution of the echoes in space, time and energy. By combining observations of many echoes, a composite picture can be obtained of the beam patterns. Atmospheric scattering at the conjugate point of Wallops Island has been extensively studied, and the process produces a scale width of 5-10 m, but with an echo intensity which is only 10% of theoretical estimates.

Winckler, J. R.↗
NASA NTRS1973

Ionospheric effects on one-way timing signals

A proposed navigation concept requires that a user measure the time-delay that satellite-emitted signals experience in traversing the distance between satellite and user. Simultaneous measurement of the propagation time from four different satellites permits the user to determine his position and clock bias if satellite ephemerides and signal propagation velocity are known. A pulse propagating through the ionosphere is slowed down somewhat, giving an apparent range that is larger than the equivalent free space range. The difference between the apparent range and the true range, or the free space velocity and the true velocity, is the quantity of interest. This quantity is directly proportional to the total electron content along the path of the propagating signal. Thus, if the total electron content is known, or is measured, a perfect correction to ranging could be performed. Faraday polarization measurements are continuously being taken at Fort Monmouth, N. J., using beacon emissions of the ATS-3 (137.35 MHz) satellite. Day-to-day variability of the diurnal variation of total electron content values is present with differences of up to 50% or more not being uncommon. In addition, superposed on the overall diurnal variation are smaller scale variations of approximately 5 to 10% of the total content which are attributed to ionospheric density irregularities.

Soicher, H.↗
NASA NTRS1974

Ground effects on Loran-C signals

In conjunction with the test and evaluation of the position fixing capabilities of the Army Manpack Loran Receiver AN/PSN-6, an extensive series of time difference and signal amplitude measurements were made within a 100 km map grid square encompassing Fort Monmouth, New Jersey. The test location is within the coverage area of the East Coast Loran-C Chain. The data were used to develop a simple smooth-earth model for the test area as well as to estimate the magnitude and distributions of deviations from this model. Local propagation processes associated with topographic features and the grid of overhead wires in the test area are shown to contribute to the deviations from the model.

Pearce, D. C.↗
NASA NTRS1974

Near-simultaneous measurement of low-energy electrons by sounding rocket and satellite

An auroral sounding rocket was launched from Fort Churchill at 0453 UT on April 24, 1968. At the time of the rocket flight, the Vela 3B satellite was passing through the magnetotail plasma sheet at very nearly the same magnetic local time. Electron spectra obtained from experiments on these vehicles are well described by central Maxwell-Boltzmann populations, with indications of a high-energy tail; the satellite spectra also suggest the presence of a low-energy tail. The higher-temperature spectra measured on the rocket may be derived from the satellite spectra by adiabatic compression.

Rearwin, S.↗
NASA NTRS1974

Investigations of acoustic-seismic effects at long range - Early-arriving seismic waves from Apollo 16

A reasonably comprehensive technical effort is described dealing with the investigations of acoustically generated seismic waves of Apollo 16 and Apollo 17 origin along the eastern seabord of the United States. This expanded effort is a continuation of earlier, rather successful detections of rocket-generated seismic disturbances on Skidaway Island, Georgia. The more recent effort has yielded few positive results other than a recording of an early-arriving seismic wave from Apollo 16 that was detected in Jacksonville. Evaluation of the negative results obtained in the Fort Monmouth area, with earlier studies of infrasound, local weather conditions, and geology, could be advantageous in the process of trying to gain a better insight into the acoustic-seismic resonance mechanism requiring phase-velocity matching at the atmosphere-ground interface.

Dalins, I.↗
NASA NTRS1975

A measurement of cosmic-ray positron and negatron spectra between 50 and 800 MV

A balloon-borne spark chamber magnetic spectrometer has been used to measure the spectra of cosmic-ray positrons and negatrons at energies between 50 and 800 MV. The data reported here were obtained during two flights from Fort Churchill, Manitoba, in July 1972. The present results indicate that the dominance of negatrons from primary sources, found in earlier experiments above 200 MV, extends down to at least 50 MV. Solar modulation of the positron component is found to be consistent with that of the total electron spectrum, assuming that the positron component is entirely attributable to collisions between cosmic-ray nuclei and the interstellar gas.

Daugherty, J. K.↗
NASA NTRS1975

Small-scale imagery: A useful tool for mapping geological features in the Texas Gulf Coastal plain

A sample of satellite imagery includes photographs and multispectral scanner imagery from the Apollo, LANDSAT, and Skylab spacecraft over an area west of Houston, Texas. Large circular features and lineaments can readily be mapped. One of the circular features identified by drainage, vegetation, and soil-tone anomalies, occurs in Fort Bend County, Texas, and covers an area about 25 miles in diameter. Another circular feature lies to the north, immediately west of Houston, and is about 15 miles in diameter. These features represent the surface expression of deeply-buried positive structures. It is recommended that regional geological studies begin with photointerpretations of high-altitude aircraft and synoptic space imagery, space imagery provides the synoptic view of rapid evaluation of large-scale features, and, at enlarged scales, the resolution required for detailed study of selected areas of structures.

Amsbury, D. L.↗
NASA NTRS1975

Data set for background investigation of atmospheric constituents for Cape Henry site: August 5-22, 1974

The laboratory was located within the Fort Story Military Reservation at Cape Henry between 5 August and 21 August 1974. Total sulfur, total hydrocarbons, NO, NO2, Nox, and O3 were monitored and reported as hourly averages. Visibility was measured using an integrating nephelometer and reported as hourly averages. Twenty-four hour averaged mass loading was determined using two high volume air samplers located on different levels (25' and 50') at the site. Temperature, wind speed, relative humidity, barometric pressure and solar radiation intensity were measured at the site or supplemented by readings taken by the U. S. Coast Guard at the Cape Henry Light House.

Source record↗
NASA NTRS1975

Observations of an intense field-aligned thermal ion flow and associated intense narrow band electric field oscillations

An investigation is conducted concerning the conditions encountered during a Javelin sounding rocket experiment conducted on Apr. 3, 1970 at Fort Churchill, Canada. Evidence is presented that near the equatorward edge of the auroral arc an intense beam of cold plasma ions was flowing parallel to the earth's magnetic field. The beam was associated with intense narrow band electric field oscillations near the local ion gyrofrequency. The data support the hypothesis that intense electrostatic ion cyclotron waves were driven unstable by field-aligned currents.

Bering, E. A.↗
NASA NTRS1975

Measurement of auroral Birkeland currents

Results are presented for measurements of the auroral current made with a rocket-borne experiment over Fort Churchill, Canada, during the February-May period in 1968. On the upward leg of the rocket flight there were detected a westward auroral current of 10,000 A near 96 km altitude and two oppositely directed Birkeland currents of about 0.00005 A per sq m at about 160 km altitude. On the downward leg there were revealed a westward filament of current of about 0.0008 A per sq m at about 220 km altitude, two oppositely directed Birkeland sheet currents of about 0.00014 A per sq m at about 230 km altitude, and two oppositely directed Birkeland currents of about 0.00007 A per sq m which fed a westward auroral electrojet of about 0.0010 A per sq m at about 100 km altitude and were associated with a bright rayed arc. A reversal in the Birkeland current system near midnight was also observed. These observations are probably manifestations of the complex nature of small-scale currents associated with complicated auroral forms.

Ifedili, S. O.↗
NASA NTRS1977

Lightweight, low compression aircraft diesel engine

The feasibility of converting a spark ignition aircraft engine to the diesel cycle was investigated. Procedures necessary for converting a single cylinder GTS10-520 are described as well as a single cylinder diesel engine test program. The modification of the engine for the hot port cooling concept is discussed. A digital computer graphics simulation of a twin engine aircraft incorporating the diesel engine and Hot Fort concept is presented showing some potential gains in aircraft performance. Sample results of the computer program used in the simulation are included.

Gaynor, T. L.↗
NASA NTRS1978

Initial test results with a single-cylinder rhombic-drive Stirling engine

A 6 kW (8 hp), single-cylinder, rhombic-drive Stirling engine was restored to operating condition, and preliminary characterization tests run with hydrogen and helium as the working gases. Initial tests show the engine brake specific fuel consumption (BSFC) with hydrogen working gas to be within the range of BSFC observed by the Army at Fort Belvoir, Virginia, in 1966. The minimum system specific fuel consumption (SFC) observed during the initial tests with hydrogen was 669 g/kW hr (1.1 lb/hpx hr), compared with 620 g/kWx hr (1.02 lb/hpx hr) for the Army tests. However, the engine output power for a given mean compression-space pressure was lower than for the Army tests. The observed output power at a working-space pressure of 5 MPa (725 psig) was 3.27 kW (4.39 hp) for the initial tests and 3.80 kW (5.09 hp) for the Army tests. As expected, the engine power with helium was substantially lower than with hydrogen.

Cairelli, J. E.↗
NASA NTRS1977

A multispectral analysis of algal bloom in the Gulf of Mexico

Skylab multispectral scanner data acquired on January 21, 1974, were used to study the spectral characteristics of an algal bloom in the Gulf of Mexico west of Fort Myers, Florida. Radiance profiles of the water and algae were prepared with data from ten bands of the S192 scanner covering the spectral range from .42 to 2.35 micrometers. The high spectral response in the near-infrared spectral bands implies a possible classification and discrimination parameter for detection of blooms of phytoplankton concentrations such as the so-called red tides of Florida.

Johnson, W. R.↗
NASA NTRS1978

The McDonald Observatory lunar laser ranging project

A summary of the activities of the McDonald lunar laser ranging station at Fort Davis for the FY 77-78 fiscal year is presented. The lunar laser experiment uses the observatory 2.7m reflecting telescope on a thrice-per-day, 21-day-per-lunation schedule. Data are recorded on magnetic tapes and sent to the University of Texas at Austin where the data is processed. After processing, the data is distributed to interested analysis centers and later to the National Space Science Data Center where it is available for routine distribution. Detailed reports are published on the McDonald operations after every fourth lunation or approximately once every 115 days. These reports contain a day-by-day documentation of the ranging activity, detailed discussions of the equipment development efforts, and an abundance of other information as is needed to document and archive this important data type.

Silverberg, E. C.↗
NASA NTRS1979

Analyses of mean and turbulent motion in the tropics with the use of unequally spaced data

Wind velocities from 25 km to 60 km over Ascension Island, Fort Sherman and Kwajalein for the period January 1970 to December 1971 are analyzed in order to achieve a better understanding of the mean flow, the eddy kinetic energy and the Eulerian time spectra of the eddy kinetic energy. Since the data are unequally spaced in time, techniques of one-dimensional covariance theory were utilized and an unequally spaced time series analysis was accomplished. The theoretical equations for two-dimensional analysis or wavenumber frequency analysis of unequally spaced data were developed. Analysis of the turbulent winds and the average seasonal variance and eddy kinetic energy of the turbulent winds indicated that maximum total variance and energy is associated with the east-west velocity component. This is particularly true for long period seasonal waves which dominate the total energy spectrum. Additionally, there is an energy shift for the east-west component into the longer period waves with altitude increasing from 30 km to 50 km.

Kao, S. K.↗
NASA NTRS1979

Vertical motions in the equatorial middle atmosphere

A single station vertical velocity equation which considers ageostrophic and diabatic effects derived from the first law of thermodynamics and a generalized thermal wind relation is presented. An analysis and verification procedure which accounts for measurement and calculation errors as well as time and space continuity arguments and theoretical predictions are described. Vertical velocities are calculated at every kilometer between 25 and 60 km and for approximately every three hours for the above diurnal period at Kourou (French Guiana), Fort Sherman (Panama Canal Zone), Ascension Island, Antigua (British West Indies) and Natal (Brazil). The results, plotted as time series cross sections, suggest vertical motions ranging in magnitude from 1 or 2 cm/sec at 30 km to as much as 15 cm/sec at 60 km. Many of the general features of the results agree well with atmospheric tidal predictions but many particular features suggest that both smaller time scale gravity waves (periods less than 6 hours) and synoptic type waves (periods greater than 1 day) may be interacting significantly with the tidal fields. The results suggest that vertical motions can be calculated for the equatorial middle atmosphere and must be considered a significant part of the motion for time scales from 8 to 24 hours.

Weisman, M. L.↗
NASA NTRS1979

Lunar laser ranging data identification and management

Activity under the subject grant during the first half of fiscal year 1979 at the University of Texas at Austin is reported. Raw lunar laser ranging data submitted by McDonald Observatory, Fort Davis, Texas and by the Australian Division of National Mapping at Orroral Valley, Australia were processed. This processing includes the filtering of signal events from noise photons, normal point formation, data archive management, and data distribution. System-wide program maintenance and up-grade carried out wherever and whenever necessary. Lunar laser ranging data is being transmitted from Austin to Paris for the extraction of earth rotation information during the EROLD campaign.

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