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  • Other Sources  (5,457)
  • ENERGY PRODUCTION AND CONVERSION  (2,381)
  • ASTROPHYSICS  (2,156)
  • SPACECRAFT DESIGN, TESTING AND PERFORMANCE  (920)
  • Life and Medical Sciences
  • 1975-1979  (5,453)
  • 1960-1964  (4)
  • 1955-1959
  • 1950-1954
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  • 1
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    DSN energy data base preliminary design (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-01
    Description: The design and implementation of a computerized data base created to support the DSN Energy Conservation Project with data relating to energy use at Goldstone Deep Space Communications Complex are described. The results of development work to date, are presented along with work currently in progress or in the planning stage.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: The Deep Space Network; p 167-181
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  • 2
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    Further development of the multipactor discharge electron source (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A modification to the multipactor electron source used in the study of the behavior of spacecraft insulating materials is described. The electron accelerating system was included within the source, freeing the region between the source and the target of fields produced by the source electrodes.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 881-886
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  • 3
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    The Qualification of a large electron irradiation facility for telecommunication satellite differential charging simulation (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The definition and procurement program is presented for the set up of a test simulating an electron environment on a model of a communication satellite to study the degradation of the thermal insulation materials during electron bombardment.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 819-833
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  • 4
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    Secondary electron effects on spacecraft charging (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Calculations were conducted to determine the effects of electron-produced secondary electrons on the net charging current and the equilibrium voltage of spacecraft surfaces immersed in hot (keV) plasmas. The effects of secondary electrons produced by the primary plasma electrons were examined for aluminum, Teflon, Mylar, and Kapton. The results indicate that it is the primary electron energy region over which the secondary electrons are emitted (rather than the ratio of secondary to primary electrons) which determines the effectiveness of the secondary electrons in limiting the net charging current. While the electron-produced secondary electrons decreased the charging current, they had little effect upon the equilibrium voltages attained.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 756-768
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  • 5
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    Parameter dependence of equilibrium charging potentials (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Equilibrium surface potentials for slab configurations (representative e.g. of a large solar power satellite) are determined under extensive parametric variations of materials, solar exposure and substorm characteristics. The dependence of the charging process for dielectric surfaces on the various material response characteristics is described. The results are used as a guide to the material selection and design of large space systems to minimize dielectric breakdowns and reduce parasitic leakage currents on SPS.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA Lewis Res. Center Spacecraft Charging Technol., 1978; p 711-733
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  • 6
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    Thermal blanket metallic film groundstrap and second surface mirror vulnerability to arc discharges (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Available data on the geosynchronous orbit energetic plasma environment were examined, and a crude model was generated to permit an estimation to be made of the number of arc discharges per year to which a thermal blanket groundstrap would be subjected. Laboratory experiments and a survey of the literature on arc discharge characteristics were performed to define typical and worst case arc discharge current waveforms. In-air tests of different groundstrap configurations to a standardized test pulse were performed and a wide variability of durability values were found. A groundstrap technique, not used thus far, was found to be far superior than the others.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 657-681
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  • 7
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    Secondary emission effects on spacecraft charging: Energy distribution considerations (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The conditions under which multiple valued solutions occur by computing the floating potential of an isolated eclipses surface on a geosynchronous orbit spacecraft were examined. Different approximations for the electron spectra during a geomagnetic substorm were used. The result indicates that if the incident electron flux has a Maxwellian energy distribution, the ratio of the secondary emitted current to the incident electron current is independent of the spacecraft potential. In this case a single value solution to the current equation occurs.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 747-755
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  • 8
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    Model for breakdown process in dielectric discharges (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A heuristic model to explain the blowoff of charge during an electron-induced dielectric discharge is presented. It is proposed that blowoff of charge is initiated by a punchthrough or a flashover. The discharge time is assumed to be governed by an LC time constant where L is the inductance of the electrons flowing in the branches of the Lichtenberg figures at an electron range below the irradiated surface and C is the capacitance between the trapped electrons and the substrate for the discharged area. Experiments to verify that blowoff is a consequence of punchthrough or flashover and to measure the punchthrough current and the variation of discharge time with the sample area and thickness were conducted.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 704-710
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  • 9
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    Area scaling investigations of charging phenomena (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The charging and discharging behavior of square, planar samples of silvered, fluorinated ethylene-propylene (FEP) Teflon thermal control tape was measured. The equilibrium voltage profiles scaled with the width of the sample. A wide range of discharge pulse characteristics was observed, and the area dependences of the peak current, charge, and pulse widths are described. The observed scaling of the peak currents with area was weaker than that previously reported. The discharge parameters were observed to depend strongly on the grounding impedance and the beam voltage. Preliminary results suggest that measuring only the return-current-pulse characteristics is not adequate to describe the spacecraft discharging behavior of this material. The seams between strips of tape appear to play a fundamental role in determining the discharging behavior. An approximate propagation velocity for the charge cleanoff was extracted from the data. The samples - 232, 1265, and 5058 square centimeters in area - were exposed at ambient temperature to a 1- to 2-nA/sq cm electron beam at energies of 10, 15, and 20 kilovolts in a 19-meter-long by 4.6-meter-diameter simulation facility at the Lewis Research Center.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 485-506
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  • 10
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    Plasma particle trajectories around spacecraft propelled by ion thrusters (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The thruster plasma is assumed to be described by a collimated energetic beam and a cloud of ionized thermal propellant produced by charge-exchange. A simple adiabatic model is used to describe the expansion of these neutral plasmas away from the source. As the pressure falls, shielding currents dissipate, and the geomagnetic field takes control of the particles. In low earth orbit, it is concluded that the vehicle easily outruns its thruster plasma. At geosynchronous altitude, the local electric fields around high voltage surfaces collect return current from the thermal plasma that appears to be limited only by the available space charge. Results appropriate to proposed electric propulsion missions and the solar power satellite are presented and operational considerations are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 419-436
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  • 11
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    Effect of parasitic plasma currents on solar-array power output (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Solar-array voltage-current curves are calculated by assuming the existence of parasitic loads that consist of local currents of charged particles collected by the array. Three cases of interest are calculated to demonstrate how the distribution and magnitude of parasitic currents affect output. Solar array performance degradation became significant when the total parasitic current plus the load current exceeded the short-circuit current. Approximate graphical methods were useful for many applications. Power loss, which was calculated by summing the product of parasitic current and the local potential, underestimated the loss in maximum power.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 358-375
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  • 12
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    Magnetic shielding of large high-power-satellite solar arrays using internal currents (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Present concepts for solar power satellites involve dimensions up to tens of kilometers and operating internal currents up to hundreds of kiloamperes. A question addressed is whether the local magnetic fields generated by these strong currents during normal operation can shield the array against impacts by plasma ions and electrons (and from thruster plasmas) which can cause possible losses such as power leakage and surface erosion. One of several prototype concepts was modeled by a long narrow rectangular panel 2 km wide and 20 km long. The currents flow in a parallel across the narrow dimension (sheet current) and along the edge (wire currents). The wire currents accumulate from zero to 100 kiloamp and are the dominant sources. The magnetic field is approximated analytically. The equations of motion for charged particles in this magnetic field are analyzed. The ion and electron fluxes at points on the surface are represented analytically for monoenergetic distributions and are evaluated.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 376-387
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  • 13
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    Spacecraft potential control on ISEE-1 (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Active control of the potential of the ISEE-1 satellite by the use of electron guns is reviewed. The electron guns contain a special cathode capable of emitting an electron current selectable between 10 to the -8th power and 10 to the -3rd power at energies from approximately .6 to 41 eV. Results obtained during flight show that the satellite potential can be stabilized at a value more positive than the normally positive floating potential. The electron guns also reduce the spin modulation of the spacecraft potential which is due to the aspect dependent photoemission of the long booms. Plasma parameters like electron temperature and density can be deduced from the variation of the spacecraft potential as a function of the gun current. The effects of electron beam emission on other experiments are briefly mentioned.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 256-267
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  • 14
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    Electron transport model of dielectric charging (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A computer code (SCCPOEM) was assembled to describe the charging of dielectrics due to irradiation by electrons. The primary purpose for developing the code was to make available a convenient tool for studying the internal fields and charge densities in electron-irradiated dielectrics. The code, which is based on the primary electron transport code POEM, is applicable to arbitrary dielectrics, source spectra, and current time histories. The code calculations are illustrated by a series of semianalytical solutions. Calculations to date suggest that the front face electric field is insufficient to cause breakdown, but that bulk breakdown fields can easily be exceeded.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 209-238
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  • 15
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    Design, development, and flight of a spacecraft charging sounding rocket payload (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Results of the flight of the spacecraft charging sounding rocket payload are given. The payload was designed to create charging by the emission of both positive ions and electrons. The relationship between environmental parameters and changes in vehicle potential during periods of emission was also studied.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 80-90
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  • 16
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    Precise determination of the distances of galaxies (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The use of the Space Telescope in the determination of the distances of galaxies is examined. The Space Telescope can check the local extragalactic distance scale to within 10-15 percent. The determination of relative distances of cosmic standard candles, viz. brightest M-supergiants and SNe I in E galaxies, is discussed. The M-supergiants map the velocity field out to v sub o approx. 3000 km s(-1) thus providing a firm basis for the determination of H sub o (global) from local distances, and the possibility to derive precise distances of all nearby field galaxies from their recession velocities. Photometry of the SNe I out to z = 0.5 leads to a direct determination of q sub o via the Hubble diagram, and the form of their light curves offers a fundamental test on the nature of redshifts. Other calculations are discussed.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 263-293
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  • 17
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    Development of the Transient Pulse Monitor (TPM) for Scatha/P78-2 (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: An instrumentation system developed for the detection of electrical transients on space vehicles is presented. The pulse monitor measures the electron pulse environment on a spacecraft at synchronous altitude, and characterizes signals produced by arcing between differentially charged elements on the spacecraft.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 876-880
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  • 18
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    A combined spacecraft charging and pulsed X-ray simulation facility (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A spacecraft charging simulation facility constructed to investigate the response of satellite materials in a typical geomagnetic substorm environment is described. The conditions simulated include vacuum, solar radiation, and substorm electrons. A nuclear threat environment simulation using a flash X ray generator is combined with the spacecraft charging facility. Results obtained on a solar cell array segment used for a preliminary facility demonstration are presented with a description of the facility.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 854-867
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  • 19
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    Investigation of electrostatic discharge phenomena on conductive and non-conductive solar reflectors (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A sample composed of non conductive optical solar reflectors (OSR) was irradiated with low energy electrons at the DERTS facility to study the effects of charge build up on thermal control coating materials. The degration effects on this panel due to electrostatic discharges were investigated to find possible alternatives to limit the amount of damage. The following systems are evaluated: (1) non conductive OSR (non conductive adhesive) (2) non conductive OSR (conductive adhesive); and conductive OSR (conductive adhesive).
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol.; p 682-703
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  • 20
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    Effects of electron irradiation on large insulating surfaces used for European Communications Satellites (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Samples of aluminized Kapton used for passive thermal control on the VHF shield and the antenna dish of ESA's OTS satellite and its derivatives were subjected to an incident electron beam of 25 keV and irradiated for 8 hours at room temperature and at -173 C under a vacuum of the 10 to the minus 6 th power torr. Visual observations during electron irradiation, measurements of leakage current and discharge characteristics, and material degradation following completion of irradiation are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 570-586
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  • 21
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    Electric fields in irradiated dielectrics (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: An existing model for quantitatively predicting electric field build-up in dielectrics is used to demonstrate the importance of material parameters. Results indicate that electron irradiation will produce 10 to the 6th power V/cm in important materials. Parameters which can alter this build-up are discussed. Comparison to known irradiation induced dielectric charging experiments is discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 554-569
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  • 22
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    Interactions between spacecraft and the charged-particle environment (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Spacecraft-environment interactions are defined as the responses of a spacecraft surface to a charged-particle environment. This response can influence spacecraft system performance. Interactions can be divided into two broad categories: spacecraft passive, in which the environment acts on the spacecraft; and spacecraft active, in which the spacecraft causes the interaction. Passive interactions include the spacecraft-charging phenomenon. Active interactions include the relatively new interactions arising from the use of very large spacecraft and space power systems in future missions. To illustrate active interactions, a large power system operating at elevated voltages is considered. Possible interactions are described, available experimental data are reviewed, and the effect on power system performance is estimated.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 268-294
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  • 23
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    The calculation of spacecraft potential: Comparison between theory and observation (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A simple charge balance model based on the work of DeForest was adapted for the calculation of spacecraft potentials. The model was calibrated with ATS 5 plasma data. Once calibrated, the model was used to calculate the time-varying potential that was observed as a spacecraft passes in and out of eclipse. Errors on the order of + or - 800 volts were observed over a range of 0 to -10,000 volts. Possible applications of the model to large space structures are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 239-255
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  • 24
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    Spacecraft charging results for the DSCS-3 satellite (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Spacecraft charging results are presented for the DSCS-3 satellite for a severe geomagnetic substorm. Spacecraft charging results were obtained by the use of the electrostatic charging analysis program (ESCAP). The ESCAP computer code which can determine both the transient or steady state differential charging potentials was an engineering design tool that utilized a circuit theory approach to spacecraft charging. Using the ESCAP code, the steady state (static) differential potentials of the outer spacecraft surfaces and metallic structure were obtained for the DSCS-3 satellite when under the influence of a severe geomagnetic substorm during the local midnight-to-dawn quadrant of its geosynchronous orbital path. The results indicated that, in the steady state, most of the DSCS-3 outer surface materials will not achieve differential potentials large enough to produce an electrostatic discharge.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 158-178
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  • 25
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    Comparison of NASCAP predictions with experimental data (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The NASA charging analyzer program (NASCAP) is a three dimensional, finite element computer code capable of simulating the electrostatic charging of an arbitrary body either in a ground test tank or in the space environment. The code incorporated surface property parameters needed to simulate insulating and conducting materials. These parameters are being updated as required to bring the NASCAP predictions into correspondence with data from ground tests. NASCAP predictions are also being compared with data from the ATS 5 spacecraft. The significance of these results is discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 144-157
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  • 26
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    Description of the Space Test Program P78-2 spacecraft and payloads (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The P78-2 spacecraft and its payloads are designed to measure the environment at near synchronous altitude and the interactions of the environment on the spacecraft. A brief description of each payload is provided.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 4-10
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  • 27
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    Average plasma environment at geosynchronous orbit (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The average plasma environment at geosynchronous orbit (GSO) is derived from a whole year's worth of plasma data obtained by the UCSD electrostatic electrometer on board ATS 5. The result is primarily intended for use as a general reference for engineers designing a large spacecraft to be flown at GSO. A simple mathematical formula using a 3rd order polynomial is found to be adequate for representing the yearly averaged particle energy spectrum from 70 to 41,000 eV under different geomagnetic conditions. Furthermore, correlation analyses with the geomagnetic planetary index Kp and with the auroral electrojet index AE were carried out in the hope that the ground observations of the geomagnetic field variations can be used to predict the plasma variations in space. Unfortunately, the results indicate that such forecasting is not feasible by use of these two popular geomagnetic parameters alone.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 23-37
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  • 28
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    Requirements for predictions and real-time monitoring for the study of travelling interplanetary phenomena (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Physical processes within quiescent as well as disturbed flows of solar wind plasma, energetic particles, and magnetic and electric fields from the Sun are considered. Specifically, travelling interplanetary phenomena to be studied during the years of the solar maximum of solar cycle 21 are covered. It is noted that predictions, while needed for long range, logistical planning, is secondary to the requirements of synoptic real time monitoring over a wide range of particle energies and spectral bandwidths.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 340-345
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  • 29
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    Potential prediction needs in support of energy systems (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The relationship between emerging energy systems and the natural environment is discussed, including selected examples to show that energy systems are tied to global solar terrestrial processess. The interdependence of resources, technology, and environmental impact is considered in terms of needed geophysical, atmospheric, and solar terrestrial data inputs. The need for long term basic research on the solar terrestrial system is emphasized.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 198-202
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  • 30
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    Prediction of spacecraft potentials at geosynchronous orbit (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Two relatively straightforward techniques are outlined for determining spacecraft potentials in the limit of a 'thick sheath' surrounding the spacecraft. A statistical model of the various features of the geosynchronous environment based on ATS-5 and ATS-6 data and an analytic model capable of detailed simulation of the low energy geosynchronous environment are also discussed. The results from these two environmental models are then combined with the charging models in order to provide estimates of the relationships between the geomagnetic index and spacecraft potential. The results are compared with actual potential measurements from ATS-5 and ATS-6.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 104-118
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  • 31
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    The problems of cosmology (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Three examples that illustrate the expected role of the Space Telescope in cosmological investigations are described addressing the distribution of globular star clusters, universe expansion, and other classical cosmological problems.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 295-312
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  • 32
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    The central regions of active galaxies and quasars (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Theories describing the central regions of nonthermal extragalactic sources (radio galaxies, Seyfert nuclei, quasars, etc.) are examined in the light of the experimental possibilities afforded by the Space Telescope. In particular, the theory which proposes the accretion of stars or gas onto a black hole as the explanation of the central engine is discussed. Planned observations directed towards the problem of the mass, size, and structure of the central engine, and the phenomenological questions regarding the general environment of the central engine are outlined.
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 197-214
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    Luminosity functions and evolution of globular clusters (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The stellar dynamics of globular clusters are addressed in terms of luminosity functions, chemical topics, and dynamical topics
    Keywords: ASTROPHYSICS
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 139-150
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    TDRSS solar array arc discharge tests (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Solar array design guidelines for immunity to the geomagnetic substorm environment at geosynchronous altitudes are summarized. The preliminary design guidelines and recommended practices based on these test results are given. It is concluded that specific design and immunity verification problems on each spacecraft program have to be solved on an individual basis until the technology matures to an adequate level.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 834-852
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  • 35
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    Charging rates of metal-dielectric structures (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Metal plates partially covered by 0.01-centimeter-thick fluorinated ethylene-propylene (FEP) Teflon were charged in the Lewis Research Center's geomagnetic substorm simulation facility using 5-, 8-, 10-, and 12-kilovolt electron beams. Surface voltage as a function of time was measured for various initial conditions (Teflon discharged or precharged) with the metal plate grounded or floating. Results indicate that both the charging rates and the levels to which the samples become charged are influenced by the geometry and initial charge state of the insulating surfaces. The experiments are described and the results are presented and discussed. NASA charging analyzer program (NASCAP) models of the experiments have been generated, and the predictions obtained are described. Implications of the study results for spacecraft are discussed.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 507-523
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  • 36
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    Test results for electron beam charging of flexible insulators and composites (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Flexible solar-array substrates, graphite-fiber/epoxy - aluminum honeycomb panels, and thin dielectric films were exposed to monoenergetic electron beams ranging in energy from 2 to 20 keV in the Lewis Research Center's geomagnetic-substorm-environment simulation facility to determine surface potentials, dc currents, and surface discharges. The four solar-array substrate samples consisted of Kapton sheet reinforced with fabrics of woven glass or carbon fibers. They represented different construction techniques that might be used to reduce the charge accumulation on the array back surface. Five honeycomb-panel samples were tested, two of which were representative of Voyager antenna materials and had either conductive or nonconductive painted surfaces. A third sample was of Navstar solar-array substrate material. The other two samples were of materials proposed for use on Intelsat V. All the honeycomb-panel samples had graphite-fiber/epoxy composite face sheets. The thin dielectric films were 2.54-micrometer-thick Mylar and 7.62-micrometer-thick Kapton.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 457-484
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  • 37
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    Environmental interaction implications for large space systems (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Large Space Systems (LSS) comprise a new class of spacecraft, the design and performance of which may be seriously affected by a variety of environmental interactions. The special concerns associated with spacecraft charging and plasma interactions from the LSS designer's viewpoint are addressed. Survivability of these systems under combined solar U.V., particle radiation and repeated electrical discharges is of primary importance. Additional questions regard the character of electrical discharges over very large areas, the effects of high current/voltage systems and magnitude of induced structural disturbances. A concept is described for a large scale experiment platform.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 388-407
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  • 38
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    Plasma sheath effects and voltage distributions of large high-power satellite solar arrays (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Knowledge of the floating voltage configuration of a large array in orbit is needed in order to estimate various plasma-interaction effects. The equilibrium configuration of array voltages relative to space depends on the sheath structure. The latter dependence for an exposed array is examined in the light of two finite-sheath effects. One effect is that electron currents may be seriously underestimated. The other is that a potential barrier for electrons can occur, restricting electron currents. A conducting surface is assumed on the basis of a conductivity argument. Finite-sheath effects are investigated. The results of assuming thin-sheath and thick-sheath limits on the floating configuration of a linearly connected array are studied. Sheath thickness and parasitic power leakage are estimated. Numerically computed fields using a 3-D code are displayed in the thick-sheath limit.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 341-357
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  • 39
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    Status of materials characterization studies (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: In the context of the spacecraft charging technology investigation, studies were made to characterize the response of typical spacecraft surface materials to the charging environment. The objective is to obtain an understanding of the charging and discharging behavior of such materials for the reliable prediction of spacecraft response to charging environments and as a guide for the design of future spacecraft. Materials were characterized in terms of such basic properties as resistivity and secondary emission and in terms of charging and discharging behavior in simulated charging environments.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 437-456
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  • 40
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    Space environmental effects and the solar power satellite (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Some preliminary findings regarding the interactions between the space plasma at GEO and the Marshall Space Flight Center January 1978 baseline Satellite Power Systems (SPS) design are summarized. These include the following: (1) the parasitic load will be dominated by photoelectrons and will amount to about 34 MW; (2) material of higher conductivity than kapton should be used for the solar reflector substrate and the solar cell blanket support material; (3) the satellite structure and solar reflector should be tied electrically to midpoint voltage of each solar cell array; and (4) tests should be run on the proposed solar cell cover glass material (synthetic sapphire) to determine if breakdown is expected.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 408-418
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  • 41
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    Sheath effects observed on a 10 meter high voltage panel in simulated low earth orbit plasma (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A large (1m x 10m) flat surface of conductive material was biased to high voltage (+ or - 3000 V) to simulate the behavior of a large solar array in low earth orbit. The model array was operated in a plasma environment of 1,000 to 1,000,000/cu cm, with sufficient free space around it for the resulting plasma sheaths to develop unimpeded for 5-10 meters into the surrounding plasma. Measurements of the resulting sheath thickness were obtained. The observed thickness varied approximately as V to the 3/4 power and N to the 1/2 power. This effect appears to limit total current leakage from the test array until sheath dimensions exceed about 1 meter. Total leakage current was also measured with the array.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 315-340
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  • 42
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    Plasma Interaction Experiment (PIX) flight results (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: An auxiliary payload package called PIX (plasma interaction experiment) was launched on March 5, 1978, on the LANDSAT 3 launch vehicle to study interactions between the space charged-particle environment and surfaces at high applied positive and negative voltages. Three experimental surfaces were used in this package: a plain disk to act as a control, a disk on a Kapton sheet to determine the effect of surrounding insulation on current collection, and a small solar-array segment to evaluate the effect of distributing biased surfaces among an array of insulators. Only half of the results from the 4 hours of PIX operations were recovered. The results did verify effects found in ground simulation testing. The results of this experiment are discussed in detail.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 295-314
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  • 43
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    ATS-5 and ATS-6 potentials during eclipse (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The ATS 5 and ATS 6 data for spacecraft charging during eclipse conditions is analyzed. The ATS 5 and ATS 6 charged to voltages greater than 100 volts for about 55 percent of the eclipse periods examined. The mean spacecraft potential during eclipse was 2 keV for ATS 5, and the highest potential measured was 10 kilovolts. For ATS 6, the mean potential during eclipse was 4 keV, the highest potential measured 20 keV. The average measured spacecraft potentials for both ATS 5 and 6 depend approximately linearly upon Kp. This relationship is due mainly to the dependence of electron current density on Kp near midnight. Spacecraft potentials at geosynchronous orbit may, to a rough approximation, thus be inferred from ground-based measurements of Kp, the planetary 3-hour index.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 38-43
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  • 44
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    Modeling of the geosynchronous plasma environment (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: An analytic simulation of the geosynchronous environment in terms of local time and the daily A sub P index is presented. The simulation is compared with actual statistical data from approximately 50 days of ATS 5 plasma data and 50 days of ATS 6 plasma data. At low levels of activity the model adequately simulates the local time variations of the plasma parameters. At high values of geomagnetic activity, the predicted magnitudes of the plasma parameters agree with the statistical results but the effects of multiple injections are evident in both the data and the simulation, biasing the local time variations.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Lewis Res. Center Spacecraft Charging Technol., 1978; p 11-22
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  • 45
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    Summary of the two year NASA program for active control of ATS-5/6 environmental charging (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: Experiments conducted on the ATS 5 and ATS 6 which have demonstrated the feasibility of modifying or clamping the environmentally induced potential of these spacecraft are described. The results of these experiments indicate that a thermionic electron source is capable of replacing photo-emitted electrons during eclipse. However, the utility of this type of device is limited if its emission is suppressed by local electric fields. On the other hand, it is shown that a plasma source will not only serve as a substitute for photo-emitted electrons but will also suppress differential charging of isolated elements of the spacecraft which would tend to suppress electron emission. This later device is therefore capable of clamping the potential of a spacecraft without special considerations of its coupling to the ambient plasma.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Spacecraft Charging Technol., 1978; p 44-58
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  • 46
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    The X-ray spectrum of 3C 273 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 232
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    Interstellar C2 molecules toward Zeta Persei (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A search for absorption by interstellar C2 molecules, conducted at the (2-0) Phillips band near 8760 A, is reported for three stars. No interstellar absorption is seen in the spectra of 20 Tau and Epsilon Aur, at upper limits of approximately 5 mA and 1 mA, respectively. Toward Zeta Per, however, the R(0), Q(2), and Q(4) lines are detected, and a useful upper limit on the Q(6) line is obtained. The resulting column density, 1.4 x 10 to the 13th to 2.0 x 10 to the 13th per sq cm, and the excitation temperature, T = (78 plus or minus 25) K, show acceptable agreement with an existing theoretical model of the absorbing cloud.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 232
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    Galaxies and gamma-ray astronomy (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The nature of the high-energy spectra of several types of active galaxies and their contribution to the measured diffuse gamma-ray emission between 1 and 150 MeV are considered, using X-ray spectra of active galaxies and SAS 2 data regarding the intensity upper limits to the gamma-ray emission above 35 MeV. It is found that a substantial increase in slope of the photon energy spectrum must occur in the low energy gamma-ray region for Seyfert galaxies, BL Lac objects, and emission line galaxies; the power-law spectra observed in the X-ray range must steepen substantially between 50 keV and 50 MeV. In addition, a cosmological integration shows that Seyfert galaxies, BL Lac objects, and quasars may account for most of the 1-150 MeV diffuse background, even without significant evolution.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 232
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    Magnetic Cepheids (1979)
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    Publication Date: 2011-08-17
    Description: The role of a magnetic field in the pulsational behavior of classical Cepheids has been studied by computing linearized models of pulsating stellar envelopes pervaded by a well-tangled magnetic field. It is found that the 'pulsational' masses of Cepheids that are implied by the theoretical values of the quantities Q(0), P(1)/P(0), and (possibly) P(2)/P(0) can be brought into line with the large 'evolutionary' masses, if the pressure due to the postulated magnetic field is assumed to be comparable to the thermodynamic pressure everywhere in the pulsating layers. The field strengths that are required - several hundred gauss at the surface and several ten thousand gauss at the base - are quite reasonable from the point of view of the observed magnetic fields in Cepheids. The influence of the magnetic field on the location of the blue edge of the instability strip in the H-R diagram is estimated to be very slight.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 234
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    HEAO 1 observations of the X-ray pulsar 4U 1626-67 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Results are reported for an observation of the 7-s pulsar 4U 1626-67 with the A-2 experiment on HEAO 1. The phase-averaged X-ray spectrum between 0.7 and 60 keV is complex, as are the constituent spectra, which change radically as a function of pulse phase. Included in this spectral change is the sudden appearance and subsequent decay of a continuum or emission feature with a mean energy of 19 keV, which contains about one-half the power in this spectral range. Pulse-timing results include a new determination of the pulse period and a factor of 8 reduction in the upper limit for the light travel time for orbital periods between 1 and 7 hours. These findings are discussed and compared with the general nature of pulsar spectra.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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    Statistical equilibrium in cometary C2. II - Swan/Phillips band ratios (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Statistical equilibrium calculations have been made for both the triplet and ground state singlets for C2 in comets, using the exchange rate as a free parameter. The predictions of the results are consistent with optical observations and may be tested definitively by accurate observations of the Phillips and Swan band ratios. Comparison with the one reported observation indicates compatibility with a low exchange rate and resonance fluorescence statistical equilibrium.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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    Stability bounds for the control of large space structures (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Balas (1977) has discussed the stability problem of reduced-order regulators and estimators in terms of control and observation 'spillover'. The term 'control spillover' was used to define that part of the feedback control which excites the uncontrolled (or residual) modes, and 'observation spillover' was used to define that part of the measurement which is contaminated by residual modes. In this paper, two sufficient conditions are derived via Lyapunov methods for asymptotic stability of large space structures using a class of reduced-order controllers. These conditions give allowable bounds on the spectral norms of control and observation spillover terms. The sufficient condition given by a specified inequality equation appears to be less conservative, and should be useful as a design tool for the control of large space structures.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Guidance and Control; 2; July-Aug
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    Pioneer 10 studies of interplanetary shocks at large heliocentric distances (1979)
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    Publication Date: 2011-08-17
    Description: Pioneer 10 Ames plasma analyzer data collected in the 6.1 to 12.6 AU range of heliocentric distances (November 1974 to April 1977) have been examined for interplanetary shock waves. Eighteen shock signatures have been identified, with four of these being of the reverse type and the remainder the forward type. Sonic Mach numbers in the range from 3 to 10 are estimated for these events.
    Keywords: ASTROPHYSICS
    Type: Geophysical Research Letters; 6; June 197
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    Discovery of two distorted interstellar bubbles (1979)
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    Publication Date: 2011-08-17
    Description: During an extensive program of direct imagery of emission nebulae, arcuate structures have been found around two stars. A well-defined shocklike structure is found about the T Orionis variable LL Ori, located to the side of the Orion Nebula. A less extensive shocklike structure is also found about the runaway star Zeta Oph. These structures can be best described in terms of distorted interstellar bubbles. A direct consequence of this interpretation is an independent estimate of the rates of mass loss for these stars.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 23
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    An upper limit for the total energy of relativistic particles contained in the early stages of supernova explosions (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A model is proposed for the emission of X-rays from supernova explosions wherein the thermal distribution of photons from a supernova photosphere is inverse Compton scattered by relativistic electrons within or near the surface of the star. Using this model, upper limits for the number of relativistic electrons and their total energy are established on the basis of upper limits to the observed X-ray luminosity of a supernova during maximum light. These upper limits, in conjunction with radio frequency upper limits obtained by Brown and Marscher, strongly suggest that supernovae do not produce significant numbers of relativistic particles until at least 70 years after the initial outburst. This, in turn, implies that young supernovae cannot account for the radio and X-ray variability of active galactic nuclei and quasars.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 230
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    Gamma rays from accretion onto rotating black holes (1979)
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    Publication Date: 2011-08-17
    Description: Ionized matter falling onto an isolated rotating black hole will be heated sufficiently that proton-proton collisions will produce mesons, including neutral pions, which decay into gamma rays. For massive (1000-solar mass) black holes, the resulting gamma-ray luminosity may exceed 10 to the 36th erg/s with a spectrum peaked near 20 MeV.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 74; 1, Ap; Apr. 197
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    Sporadic mass ejection in red supergiants (1979)
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    Publication Date: 2011-08-17
    Description: A general mechanism first proposed by Burke (1969) is applied to red supergiants for determining the spin-down rate and angular-momentum loss of rotating stars. This model relies principally on sporadic mass ejection, which is assumed to be the result of turbulent elements accelerating material in cool supergiant atmospheres. Mass is preferentially expelled in the forward direction of rotation, resulting in a rapid loss of angular momentum on time scales of 10,000 to 1 million years in the supergiant evolutionary phase. Such rotational breaking will occur if the turbulent elements have characteristic sizes a few percent of the stellar radius and rms velocities one-third the escape speed of the star. This model predicts the formation of a cool silicate disk or torus around the star because of the preferred expulsion of material near equatorial regions of the supergiant.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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    Absorption models for low-frequency variability in compact radio sources (1979)
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    Publication Date: 2011-08-17
    Description: The consequences of the most plausible version of the absorption model for low-frequency variability in compact extragalactic radio sources are considered. The general restrictions placed on such a model are determined, and observational tests are suggested that can be used either to support the model or to discriminate among its various versions. It is shown that low-frequency variability in compact radio sources can be successfully explained by a class of models in which the flux is modulated by changes in free-free optical depth within an intervening ionized medium. Two versions of such a model are distinguished, one involving large changes in optical depth and the other, small changes. It is noted that while absorption effects are capable of causing rapid flux and structural variations at centimetric wavelengths, the models predict detailed behavior that is in direct conflict with observational data.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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  • 59
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    Comptonization of X-rays by low-temperature electrons (1979)
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    Publication Date: 2011-08-17
    Description: A method is described for calculating the spectrum that results from the Compton scattering of a monochromatic source of X-rays by low-temperature electrons, both for initial-value relaxation problems and for steady-state spatial diffusion problems. The method gives an exact solution of the inital-value problem for evolution of the spectrum in an infinite homogeneous medium if Klein-Nishina corrections to the Thomson cross section are neglected. This, together with approximate solutions for problems in which Klein-Nishina corrections are significant and/or spatial diffusion occurs, shows spectral structure near the original photon wavelength that may be used to infer physical conditions in cosmic X-ray sources. Explicit results, shown for examples of time relaxation in an infinite medium and spatial diffusion through a uniform sphere, are compared with results obtained by Monte Carlo calculations and by solving the appropriate Fokker-Planck equation.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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    Photoneutrino reactions in a superstrong magnetoactive plasma (1979)
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    Publication Date: 2011-08-17
    Description: The neutrino luminosity due to the photoneutrino process in the presence of a superstrong magnetoactive electron plasma appropriate for neutron stars is computed. The results indicate that for relatively low temperatures, between 100 million and 500 million K, the energy loss rate is significantly reduced both in the low-density regime below about 10 million g/cu cm (by the magnetic field) and in the high-density regime above that value (by plasmon excitations). These effects are temperature dependent, and they are less pronounced when the temperature is in the range from 500 million to 1 billion K.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 227
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    Detection of HC/O-18//plus/ in Sagittarius B2 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Line emission at 85.1 GHz attributed to the J equals 1-0 rotational transition of the formyl ion HC(O-18)(plus) has been detected in Sgr B2 (OH). The double isotopic ratio (O-16/O-18)/(C-12/C-13) in the formyl ion in Sgr B2 is estimated to be in the range 5-10, hence within a factor 2 of the terrestrial value of 5.5. This determination implies that the C-13/C-12 ratio near the galactic center does not differ greatly from that in local molecular clouds.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 227
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    Contamination enhanced electrostatic discharge mechanisms (1979)
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    Description: The two problems of enhanced electrostatic discharge (ESD) and contamination are discussed. It is shown that there is a synergistic relationship between them such that one enhances the probability of occurance of the other. The action of both provides substantially more deleterious affects than the effects of both separately. Mechanisms for such a relationship are discussed as well as application to large advanced technology systems.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: ESA Spacecraft Mater. in Space Environ.; p 145-158
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    Galactic distribution models of gamma-ray burst sources (1979)
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    Publication Date: 2011-08-17
    Description: The log N-log S relationships for several galactic distribution models of gamma-ray burst sources are derived. The resulting curves are substantially different from the galactic curves usually assumed (slope = -1). There is a relatively weak dependence on the radial distribution assumed but a strong dependence on scale height. Available observational data from several experiments appear to rule out both thin disk distributions and extended halo distributions which have a strong radial density dependence. The prospects are good for obtaining self-consistent distribution data from future large-area detectors.
    Keywords: ASTROPHYSICS
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  • 64
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    Scale covariance and G-varying cosmology. II - Thermodynamics, radiation, and the 3 K background (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Within the framework of a scale-covariant theory of gravitation, a semiclassical description of particles and photons is given. Thermodynamic relations consistent with the modified conservation equations are derived. Application to a system of radiation shows that the observed 3-K background radiation can be interpreted, within the present framework, as a remnant of equilibrium radiation in the past. As the theory postulates a nonstandard coupling between gravitation and electrodynamics, the assumption that Einstein's theory of gravitation is unchanged forces modifications at the atomic level. The use of Minkowskian spacetime in atomic physics is found to be adequate only over small, but not large, time scales compared with the age of the universe. As a result, a relation between energy and the frequency of a free photon is demonstrated. Possible observational consequences of this relation are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal Supplement Series; 41; Oct. 197
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  • 65
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    Large-scale structure of X-ray clusters of galaxies (1979)
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    Publication Date: 2011-08-17
    Description: Observations from the A-2 experiment on HEAO-1 are used to search for very large-scale structure (exceeding a degree) in 40 X-ray sources in clusters of galaxies. Significant evidence for extension is found only in the relatively nearby Perseus and Virgo clusters. For the remainder of the sources the results place stringent limits on the flux in any very large component.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 189
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  • 66
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    The violent interstellar medium (1979)
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    Publication Date: 2011-08-17
    Description: Observational evidence for high-velocity and high-temperature interstellar gas is reviewed. The physical processes that characterize this gas are described, including the ionization and emissivity of coronal gas, the behavior and appearance of high-velocity shocks, and interfaces between coronal gas and cooler interstellar gas. Hydrodynamical models for the action of supernova explosions and stellar winds on the interstellar medium are examined, and recent attempts to synthesize all the processes considered into a global model for the interstellar medium are discussed.
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  • 67
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    A device model for the tandem junction solar cell (1979)
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    Publication Date: 2011-08-17
    Description: A conceptual device model has been developed to explain operation of the tandem junction cell (TJC) when back contacts only are used. Operation and parameters of the cell are explained by transistor action. Experimental observations are presented which confirm that current is collected for carrier generation in the front uncontacted n(plus) region. The model should be useful as a guideline to optimize the TJC by application of transistor design principles.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-26; Sept
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  • 68
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    HEAO 1 observations of 4U1232+07 (1979)
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    Publication Date: 2011-08-17
    Description: An analysis of the NRL HEAO 1 observations of the Virgo cluster and 3C 273 has revealed X-ray emission from a region between these two objects. The most satisfactory explanation is the presence of two weak X-ray sources, for which error boxes have been obtained. One source is likely to be the peculiar galaxy IC 3576, suggested by Margon et al. (1972) as the source 2U 1231+07=4U 1232+07. The error box resulting from combining the present observations with the 4U data strengthen the X-ray identification with this extremely interesting galaxy. There are numerous possibilities for the other X-ray source, including the interacting pair of galaxies NGC 4410a and NGC 4410b (NGC 4410a/b).
    Keywords: ASTROPHYSICS
    Type: Nature; 281; Oct. 11
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  • 69
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    Pointing and control of planetary spacecraft - The next 20 years (1979)
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    Publication Date: 2011-08-17
    Description: Four basic categories of spacecraft pointing and control systems are discussed: (1) spin stabilized, (2) dual spin, (3) three-axis, and (4) momentum bias. Goals, mission requirements, and payloads should be considered for selection of control systems. A set of representative requirements, including life and environmental, vehicle/payload orientation and accuracy requirements, and control-system operational and functional requirements are discussed. Attention is given to design constraints imposed by the system selection. It is noted that sensitivity of any system design to increasing accuracy and flexibility in science-mission reprogramming will be major cost factors.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 17; Oct. 197
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  • 70
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    The importance of surface recombination and energy-bandgap narrowing in p-n-junction silicon solar cells (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Experimental data demonstrating the sensitivity of open-circuit voltage to front-surface conditions are presented for a variety of p-n-junction silicon solar cells. Analytical models accounting for the data are defined and supported by additional experiments. The models and the data imply that a) surface recombination significantly limits the open-circuit voltage (and the short-circuit current) of typical silicon cells, and b) energy-bandgap narrowing is important in the manifestation of these limitations. The models suggest modifications in both the structural design and the fabrication processing of the cells that would result in substantial improvements in cell performance. The benefits of one such modification - the addition of a thin thermal silicon-dioxide layer on the front surface - are indicated experimentally.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: IEEE Transactions on Electron Devices; ED-26; Sept
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  • 71
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    VV 5-32-63/64 - The 'supermassive double galaxy' in Abell 1775 revisited (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Spectroscopy is presented for galaxies in A 1775, the cluster containing VV 5-32-63/64, an apparent double galaxy which has long been considered a gravitationally bound system with supermassive components (10 to the 13th solar masses). However, this model has run afoul of recent radio observations, which detected an extremely long straight radio tail emanating from the eastern galaxy in the pair. The present observations indicate that if both galaxies are members of the same cluster, the cluster radial-velocity dispersion (1522 km/sec) is large enough to account for the velocity difference between the two VV galaxies (1650 km/sec). It is therefore suggested that the VV galaxies are not gravitationally bound and need not be supermassive. The large velocity dispersion measured for A 1775 also strains suggested velocity dispersion vs X-ray luminosity relations for clusters of galaxies, as A 1775 has not yet been detected at X-ray wavelengths.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 91
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  • 72
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    Engineering evaluation of existing space hardware for utilization in small self-contained payloads (1979)
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    Publication Date: 2011-08-17
    Description: The NASA small self-contained payload program allows research and development experiments of less than 5 cu ft to be flown in the Orbiter payload bay on a space available basis. Materials processing equipment available from Apollo, Skylab, SPAR, and MEA that include such items as furnaces for metallurgical processing and crystal growth, apparatus for measuring crystallization processes, and electrophoretic separators for cell separation are being offered by NASA through this program. Eighteen items for the self-contained payload program were evaluated and many were found to be suitable.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: ESA Mater. Sci. in Space; p 205-210
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  • 73
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    Infrared spectroscopy of stars (1979)
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    Publication Date: 2011-08-17
    Description: This paper reviews applications of IR techniques in stellar classification, studies of stellar photospheres, elemental and isotopic abundances, and the nature of remnant and ejected matter in near-circumstellar regions. Qualitative IR spectral classification of cool and hot stars is discussed, along with IR spectra of peculiar composite star systems and of obscured stars, and IR characteristics of stellar populations. The use of IR spectroscopy in theoretical modeling of stellar atmospheres is examined, IR indicators of stellar atmospheric composition are described, and contributions of IR spectroscopy to the study of stellar recycling of interstellar matter are summarized. The future of IR astronomy is also considered.
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  • 74
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    Evaluation of models to predict insolation on tilted surfaces (1979)
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    Publication Date: 2011-08-17
    Description: An empirical study was performed to evaluate the validity of various insolation models which employ either an isotropic or an anisotropic distribution approximation for sky light when predicting insolation on tilted surfaces. Data sets of measured hourly insolation values were obtained over a 6-month period using pyranometers which received diffuse and total solar radiation on a horizontal plane and total radiation on surfaces tilted toward the equator at 37 degrees and 60 degrees angles above the horizon. Data on the horizontal surfaces were used in the insolation models to predict insolation on the tilted surface; comparisons of measured vs calculated insolation on the tilted surface were examined to test the validity of the sky light approximations. It was found that the Liu-Jordan isotropic distribution model provides a good fit to empirical data under overcast skies but underestimates the amount of solar radiation incident on tilted surfaces under clear and partly cloudy conditions.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 23; 2, 19; 1979
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  • 75
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    Observed properties of interstellar dust (1979)
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    Publication Date: 2011-08-17
    Description: Recent information on the observed properties of interstellar dust is reviewed, with an attempt made to clarify some of the observational uncertainties associated with obtaining dust parameters. Attention is given to interstellar extinction, the interstellar dust distribution, the dust-to-gas ratio, and light scattering by dust grains. Interstellar polarization is also examined, along with heavy-element depletion in the interstellar medium, thermal emission from interstellar dust grains, diffuse interstellar features, and the composition and origin of interstellar grains.
    Keywords: ASTROPHYSICS
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  • 76
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    Stellar magnetic fields - The role of a magnetic field in the peculiar M giant, HD 4174 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Principles of coronal heating via basic electrodynamic effects, viz., resonant absorption of Alfven surface waves (quiescent) and magnetic tearing instabilities (impulsive), are detailed to argue three principles which may have application to late-type evolved stars. First, if one observes that B-squared/8 pi is much greater than rho times v-squared in a stellar atmosphere, then the observed magnetic field must originate in an interior dynamo. Second, low mass-loss rates could imply the presence of closed magnetic flux loops within the outer atmosphere, which constrain hydrodynamic flows when the magnetic body forces exceed the driving forces. Third, given that such magnetic loops effect an enhancement of the local heating rate, a positive correlation is predicted between the existence of a corona and low mass-loss rates. Application of these principles is made in the case of the peculiar M giant star HD 4174, which is purported to have a kilogauss magnetic field. Several of its spectroscopic peculiarities are shown to be consistent with the above principles, and further observational checks are suggested. Possible application to dMe and RS CVn objects is sketched.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 91
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  • 77
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    Physical parameter profiles of selected X-ray flares (1979)
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    Publication Date: 2011-08-17
    Description: Soft X-ray proportional-counter data for nine X-ray flares of class C1 to M1 occurring during the Skylab mission, have been analyzed to yield temperature, volume emission measure, electron density and thermal energy content. Profiles of these quantities are presented, using 1-min averages of 2.5-s resolution data. The event profiles are discussed and comparisons with previous studies made.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics Supplement Series; 38; Oct. 197
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  • 78
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    A simple theory of back-surface-field /BSF/ solar cells (1979)
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    Publication Date: 2011-08-17
    Description: An earlier calculation of the I-V characteristics of solar cells contains a mistake. The current generated by light within the depletion layer is too large by a factor of 2. When this mistake is corrected, not only are all previous conclusions unchanged, but the agreement with experiment becomes better. Results are presented in graphical form of new computations which not only take account of the factor of 2, but also include more recent data on material parameters.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Journal of Applied Physics; 50; Aug. 197
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  • 79
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    Pulse-phase spectroscopy of Hercules X-1 (1979)
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    Publication Date: 2011-08-17
    Description: The 6-18 keV and the 40-60 keV X-ray spectrum of Hercules X-1 were simultaneously observed with the A-2 experiment on HEAO-1. By combining these measurements with the results of an earlier observation of this X-ray pulsar, evidence was found for a component of emission above 40 keV which is above an extrapolation from lower energies, by a factor which depends on the phase of the pulse. These data were compared to previous hard X-ray observations and possible models were discussed.
    Keywords: ASTROPHYSICS
    Type: Royal Astronomical Society; vol. 188
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  • 80
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    Cosmic far-ultraviolet background radiation - Probe of a dense hot intergalactic medium (1979)
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    Publication Date: 2011-08-17
    Description: Line and continuum radiation fluxes have been computed for a wide range of enriched intergalactic medium (IGM) models. Observations of the diffuse extragalactic light at optical and far-ultraviolet wavelengths are found to provide a potentially important probe of a dense hot intergalactic medium. If the diffuse X-ray background is produced by this gas, the models constrain the cosmological density parameter (Omega) to be less than 0.4. The associated Compton distortions of the cosmic blackbody background radiation and the optical depths to distant quasars at X-ray wavelengths are also evaluated.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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  • 81
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    Double core evolution and X-ray binaries (1979)
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    Publication Date: 2011-08-17
    Description: The evolution of a 16-solar mass star and a 1-solar mass neutron star is followed through the common-envelope binary phase. It is found that the encounter of the neutron star with a yellow giant leads to coalescence of the two cores, while encounter with a red giant leads to hydrodynamic expansion and probable ejection of the common envelope. Within the context of the two rotation laws (1) uniform rotation (investigated in the present study), and (2) uniform specific angular momentum (considered in an earlier study), the results are independent of the choice for the angular-momentum distribution in the common envelope. Implications of the results for the binary pulsar phase are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Letters; 20; 2, 19; 1979
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  • 82
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    Reversal of the /O III/lambda 4363/H sub gamma lambda 4340 ratio in the planetary nebula IC 4997 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Five image-tube spectrograms of the planetary nebula IC 4997 obtained during August 1977 show that the intensity forbidden ratio O III 4363 A/H-gamma 4340 A was equal to unity, but a sixth one obtained in April 1978 showed the ratio to be 0.91. These results represent a significant increase in the intensity ratio, which had been declining from 1895 to 1962 (when it was considerably less than unity), and is interpreted as resulting from a gradual increase in temperature of the nebula's central star accompanied by a transient event which led to a temporarily high value for the ratio in mid-1977.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 231
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  • 83
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    X-ray observations of AM Herculis from OSO 8 (1979)
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    Publication Date: 2011-08-17
    Description: X-ray observations of the white dwarf binary system AM Herculis in the range 2 to 250 keV, taken by OSO 8, are presented and compared with balloon and Ariel 5 measurements. The composite spectrum of the 2 to 40 and 20 to 250 keV fluxes determined by the proportional counter and the high energy scintillation spectrometer, respectively, on board the satellite is shown averaged over the entire binary cycle. Variations in spectral shape and intensity between the OSO 8 results and balloon measurements taken 10 to 20 days apart are observed. Results indicate the presence of a spectral break at about 15 keV on some occasions, similar to that seen in Her X-1, however presumably caused by a different mechanism than in the neutron star. It is also considered unlikely that the gamma-ray tail observed by Ariel 5 existed during OSO 8 observations.
    Keywords: ASTROPHYSICS
    Type: Nature; 279; June 7
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  • 84
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    NGC 1275 /3C 84/ - Similar structure in the optical and 3-mm radio variations (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Optical and 3.3-mm data for the Seyfert galaxy NGC 1275 (3C 84) are compared. Similarities exist between the variations at the two wavelengths with regard to amplitude, time scale, and interval between events. The question is raised whether these similarities may be the result of a common triggering mechanism.
    Keywords: ASTROPHYSICS
    Type: Astronomical Society of the Pacific; vol. 91
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  • 85
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    Low-cost encapsulation materials for terrestrial solar cell modules (1979)
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    Publication Date: 2011-08-17
    Description: The paper presents the findings of material surveys intended to identify low cost materials which could be functional as encapsulants (by 1986) for terrestrial solar cell modules. Economic analyses have indicated that in order to meet the low cost goal of $2.70 per sq m, some or all of the following material technologies must be developed or advanced: (1) UV screening outer covers; (2) elastomeric acrylics; (3) weatherproofing and waterproofing of structural wood and paper products; (4) transparent UV stabilizers for the UV-sensitive transparent pottants; and (5) cost-effective utilization of silicone and fluorocarbon materials.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 22; 4, 19; 1979
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  • 86
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    An analysis of the infrared continuum of comets. II - Comet Kohoutek (1979)
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    Publication Date: 2011-08-17
    Description: An analysis of the infrared observations of comet Kohoutek has been carried out on the basis of silicate grain models. The 'observed' grain temperature has been obtained as a function of the heliocentric distance, and it is compared with the expected distribution. In the visible region, one requires for the refractive index, (m = n-ik), n of about 1.6 and k less than 0.05. The total number of grains varies essentially as the inverse square of radial distance; the size of the particles in the antitail of the comet Kohoutek is greater than 5 microns. The ratio of infrared flux from grains to the incident solar flux at wavelengths of a few microns is calculated.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 84; May 1979
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  • 87
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    Trends in the automation of planetary spacecraft (1979)
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    Publication Date: 2011-08-17
    Description: The automation of planetary spacecraft at the Jet Propulsion Laboratory (JPL) is discussed. Factors affecting the development of spacecraft automation, such as predictable and repetitive functions and narrow time-window, are analyzed. The volume of command data transmitted to the spacecraft is considered, together with an examination of 'autonomy' (executing functions without outside control) in relation to the ground command activity needed during the mission. The role of the spacecraft's growing computational power in increasing vehicle autonomy is noted.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 17; May 1979
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  • 88
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    Transparent electrically conducting thin films for spacecraft temperature control applications (1979)
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    Publication Date: 2011-08-17
    Description: Thin transparent films of In2O3 or In2O3 + SnO2 prepared by evaporation or sputtering have been tested for use as surface layers for spacecraft temperature control coatings. The films are intended to prevent nonuniform electric charge buildup on the spacecraft exterior. Film thicknesses of 300 to 500 A were found to be optimal in terms of durability and minimum impact on the solar absorptance and the thermal emissivity of the underlayers. As a verification of their suitability for long-duration space missions, the films were subjected to simulated solar UV plus proton irradiation in a vacuum.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Applied Optics; 18; May 15
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  • 89
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    Cool stars - Effective temperatures, angular diameters, and reddening determined from 1-5 micron flux curves and model atmospheres (1979)
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    Publication Date: 2011-08-17
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 228
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  • 90
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    Some simple properties of stellar pulsation modes (1979)
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    Publication Date: 2011-08-17
    Description: Except for the lowest harmonics, small-amplitude stellar pulsation modes possess many simple properties whose evaluation does not require numerical integration of the fourth-order equations of motion. All antinodes tend to have the same total kinetic energy except for those lying near physical or geometric boundaries. However, when kinetic energy per unit volume is considered, order-of-magnitude enhancements are seen in antinodes lying near the center of the star, and factor-of-2 enhancements occur near the polar axis. The nodes are distributed very regularly along the radius. They follow an exponential law in g-regions, and their separation is proportional to the sound travel time in p-regions. A simple graphical procedure is described for surveying the oscillation frequencies of a new stellar model. A precise condition is derived giving the division of energy between radial and angular motion. Another condition gives the fractional contribution to the velocity field of its two sources, the divergence and the curl. Certain simplifying results of weak coupling among the linear modes are briefly described.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 227
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  • 91
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    Theories of magnetospheres around accreting compact objects (1979)
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    Publication Date: 2011-08-17
    Description: The paper reviews theoretical models of magnetospheres formed around neutron stars and other strongly magnetized compact objects in the presence of mass accretion from a companion star. Emphasis is placed on the interaction of the accretion process with the magnetic field of the compact object and the formation of a magnetosphere. The following models are discussed: magnetospheres with polar funnels; closed magnetospheres and their instabilities; models of internal flow; and disk accretion magnetospheres.
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  • 92
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    The discovery of 38.22 second X-ray pulsations from the vicinity of OAO 1653-40 (1979)
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    Publication Date: 2011-08-17
    Description: A 38.22-s X-ray pulsator has been discovered during an 8-hour HEAO 1 pointed observation of the area of sky containing OAO 1653-40. It is found that this pulsing source is not associated with V861 Sco, the proposed optical identification for OAO 1653-40. The spectrum is very hard, the spectral index being about 1.4, with about a 500-eV equivalent width of iron-line emission. No high-energy cutoff is observed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 93
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    Scale covariance and G-varying cosmology. IV - The log N-log S relation (1979)
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    Publication Date: 2011-08-17
    Description: The traditional radio counts N(S) and radio source models are studied within the framework of the scale-covariant cosmology developed to investigate whether the relative strength of the gravitational and electromagnetic constants is a function of cosmological epoch. It is found that a gravitational constant G varying as the inverse of t, where t is the epoch in atomic units, is consistent with all the data analyzed. For a wide class of models the present cosmology allows a finer discrimination of the deceleration parameter than does standard theory. The results, when combined with those of previous papers, namely, those from radio and optical flux and angular-diameter data analysis, favor an open universe.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal Supplement Series; 41; Oct. 197
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  • 94
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    Infrared methane spectra between 1120 per cm and 1800 per cm - A new atlas (1979)
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    Publication Date: 2011-08-17
    Description: A new atlas of CH4 lines in the 1120-1800-per cm region has been generated, based on laboratory spectra taken with a Nicolet interferometer at 0.06-per cm resolution with 635-cm path length at pressures of 0.98 torr, 4.86 torr, and 19.97 torr. A compilation of line positions and line intensities includes 1339 CH4 lines, several hundred of which have not been previously observed.
    Keywords: ASTROPHYSICS
    Type: Applied Optics; 18; Nov. 15
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  • 95
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    Radio emission from nova shells (1979)
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    Publication Date: 2011-08-17
    Description: This paper presents data from multifrequency radio observations of the novae HR Del 1967 and FH Ser 1970 made from June 1970 to December 1978 and of V1500 Cyg 1975 made from September 1975 to December 1978. The data for FH Ser and V1500 Cyg constitute a complete history of the important phases of their radio 'light' curves, while all but the rising portion of the optically thick phase of an expanding nova shell is present for HR Del. A simple solution of the spherically symmetric equations of mass and momentum conservation for an isothermal gas, for which pressure gradients are effectively decoupled from the dynamics, is shown to fit the radio data for all three novae quite well. The main features of this model are strong density and velocity gradients that lead to long periods when the 'observable' shell evolves from an optically thick 'disk' to a completely optically thin shell.
    Keywords: ASTROPHYSICS
    Type: Astronomical Journal; 84; Oct. 197
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  • 96
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    Pointing and control of planetary spacecraft - The next 20 years (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The preliminary pointing and control systems for five planetary mission groups are presented, as well as the rationale and key characteristics for each system type. The five groups entail: (1) a preliminary survey, (2) a detailed remote observation, (3) close scrutiny in deep space, (4) close scrutiny near the sun, and (5) a sample return. Attention is given to each group with respect to two- and three-axis control and various instruments for spin control. The future development of component trends and needs, electronic trends, electromechanical development, gyros and other general system trends are discussed in detail.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 17; Nov. 197
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  • 97
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    Search for X-ray emission from bursting radio sources (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Results are reported for a systematic search with the A-2 experiment aboard HEAO 1 for X-ray emission from 28 radio sources that were actually bursting at the epoch of the X-ray observations. Two of these sources are found to lie within the positional errors of X-ray sources: the moderately redshifted quasars NRAO 140 and NRAO 530. The positions of 30 historically variable radio sources that were not active at the time of the search are compared with those of detectable X-ray sources, but no X-ray emission is detected from any of these positions. The implications of the results are discussed in terms of models for the radio emission from compact extragalactic sources. Several possible explanations are presented for the general absence of Compton X-ray emission from the bursting radio sources surveyed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 98
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    Long-term studies with the Ariel 5 ASM. II - The strong Cygnus sources (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The three bright 3-6 keV X-ray sources in Cygnus are examined for regular temporal variability with a 1300 day record from the Ariel 5 All-Sky Monitor. The only periods consistently observed are 5.6 days for Cyg X-1, 11.23 days for Cyg X-2, and 4.8 hours for Cyg X-3. The 78.4 day period of Kemp, Herman, and Barbour for Cyg X-1, the 9.843 day period of Cowley, Crampton, and Hutchings for Cyg X-2, and the 16.75 day period of Holt et al. for Cyg X-3 are not confirmed.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 99
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    Thermonuclear runaways on neutron stars (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Thermonuclear runaways which develop when neutron stars of 0.476 solar masses accrete hydrogen-rich material at 10 to the -10th and 2 x 10 to the -9th solar masses/year have been followed using a numerical model. It is found that a thermal instability occurs at densities in excess of 10 to the 5th g/cu cm and that the maximum accumulated mass required to initiate the runaway is 0.7 x 10 to the -12th and 2.1 x 10 to the -12th solar masses for the mass accretion rates of 10 to the -10th and 2 x 10 to the -9th solar masses/year, respectively. Heating the of the neutron star envelope by hydrogen burning leads to the ignition of helium. The nonequilibrium burning of helium by a combination of (alpha, p), (p, gamma), and (alpha, gamma) reactions involving O-14, O-15, and other heavy nuclei provides the energy for an X-ray burst. The gross properties of these models bear suggestive resemblance to those observed for some X-ray burst sources.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; vol. 233
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  • 100
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    Intense interplanetary magnetic fields observed by geocentric spacecraft during 1963-1975 (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: In the present paper, interplanetary magnetic field and plasma data are reviewed over a period exceeding one full solar cycle for intervals in which the magnetic intensity was greater than 13 gammas. One hundred forty nine intervals of this type, with almost complete plasma and magnetic field data, are identified. Most (79%) of these enhancements could be associated either with interplanetary shocks or with high-speed stream interfaces. Half of the remaining 21% of the enhancements could be identified as cold magnetic enhancements, while the other half could not be associated with a single shock, interface, or cold magnetic enhancement.
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 84; Nov. 1
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