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  • LUNAR AND PLANETARY EXPLORATION  (3,679)
  • GEOPHYSICS  (2,227)
  • 1975-1979  (5,906)
Collection
Keywords
Years
Year
  • 1
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    Some unique meteorites found in Antarctica and their relation to asteroids (1979)
    In:  Other Sources
    Details
    Publication Date: 2011-08-24
    Description: Two unique meteorites were identified by means of a mineralogical examination of the smaller-sized Yamato achondrites. Yamato-74130 is the most iron-rich ureilite with Na, Cr-rich augite instead of pigeonite. Yamato-74160 was extensively recrystallized, but the composition and proportion of olivine, orthopyroxene, augite, and plagioclase is consistent with LL7 chondrites. ALHA77005 is a unique achondrite with olivine, possibly three pyroxene assemblages, and maskelynite. These meteorites provide evidence that there may be other 'thermalized' asteroids than the howardite parent body. Detailed petrologic descriptions of the unique achondrites, recrystallized diogenite Yamato-74013, and the rapidly cooled eucrite Yamato-74450 with pyroxene phenocrysts are given. It is inferred from the bulk chemistry and the mineralogical reexamination of Yamato-75028 that it is composed of the H5-type clasts and chondrule-rich H(L)3-like matrix with the H5 fragments. A close relationship in the collisional evolution of some asteroids with these materials is inferred.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: National Institute of Polar Research, Memoirs (ISSN 0386-0744); 15, 1; 54-76
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  • 2
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    Meteoroid protection for the Comet Halley probe (1979)
    In:  CASI
    Details
    Publication Date: 2006-06-26
    Description: The high closing speed of 57km/s between the spacecraft and Halley poses special problems in the design of the required meteoroid protection. A double wall structure with a total thickness equal to 0.1 to 1 times the diameter of the largest meteoroid encountered is sufficient to stop that meteoroid. However, the unusually high number of meteoroid impacts on the Halley probe will cause significant erosion of the outer wall so that failure of the second wall is more likely to occur from a small meteoroid passing through a previously created hole in the outer wall and then penetrating the second wall. Calculations of the shielding required based on this failure mode, show that a double wall structure must actually have a total thickness 1.2 to 7.3 times the diameter of the largest meteoroid encountered, depending on the size distribution of the meteoroids.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: ESA Comet Halley Micrometeoroid Hazard Workshop; p 73-76
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  • 3
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    Ion production in the D region (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Ionization processes for the D region are reviewed. Levels of ionization range from the fairly steady rates produced through galactic cosmic rays to the large rates generated during solar flares and associated geomagnetic storms. The normal quiescent daytime D region is ionized by solar UV radiation available because of certain windows and solar X-rays, although this later source is generally weak. Cosmic rays are important roughly below 65 km. At night, stellar X-ray sources may be important along with precipitating electrons at high latitudes from the quiet magnetosphere. Solar flares can result in ionization rates due to X-rays, electrons, or nuclei which are greatly enhanced over quiet conditions. Typical ionization production rates from these various sources are illustrated.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 599-616
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  • 4
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    D region predictions (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Present knowledge of D region phenomena is briefly reviewed and the status of current methods of predicting their effects on radio propagation considered. The ELF, VLF and LF navigational and timing systems depend on the stability of the lower part of the D layer where these waves are reflected, whereas MF and HF waves are absorbed as they penetrate the region, in most cases mainly in the upper part of the layer. Possible methods of improving predictions, warnings, and real time operations are considered with particular stress on those which can be implemented in the near future.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 573-598
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  • 5
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    Morphology and phenomenology of the high-latitude E and F regions (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Results obtained at high latitude observatories on the behavior of E and F region ionization are presented including a bibliography. Behavior of E and F region ionization during day and night for quiet and disturbed conditions in the auroral and polar regions is described. Daily, seasonal and sunspot variations are also outlined.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 543-561
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  • 6
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    Report of the mid- and low-latitude E and F Region Working Group (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The formation and variation of the ionosphere is addressed with regard to the ability to understand, specify, and predict the low and mid latitude E and F regions. A brief survey of prediction methods and techniques is given for long and short term variability in the E and F regions. It is indicated that the usefulness of theoretical models to predict electron density distribution in the low and mid latitude ionospheric E and F regions is limited by the ability to predict the parameters which enter the relevant equations; i.e., neutral atmospheric constituents, neutral and charged particle temperatures, neutral wind, electric fields, and ionizing sources such as solar (E sub uv) radiation and energetic particles. It is recommended that areas for research include improving knowledge of the input parameters and how they respond to changing solar and geophysical conditions.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 562-572
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  • 7
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    On the approach to forecasting polar ionospheric conditions (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The major properties of polar ionospheric main anomalous events are summarized. The monitoring of large scale features of the ionization distribution that are the projections of large scale structural characteristics of magnetospheric plasma on the upper ionosphere is suggested as a basic principle of polar ionospheric condition forecasting. It is concluded that the processes of the magnetosphere/ionosphere interaction appear to play a predominant role in the creation of the polar ionosphere.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 528-542
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  • 8
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    High-latitude E and F region ionospheric predictions (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The physical processes and morphology of the high latitude E and F layers are discussed. The existence and adequacy of models, and features to be included are examined, as well as reliability of ionospheric predictions.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 513-527
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  • 9
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    Long term magnetospheric particle variations (1 day T infinity), appendix 2 (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Effects of solar variations on energetic particle propagation are discussed, as well as prediction techniques for such particles within the magnetosphere. Magnetic field models, magnetic energy stored in the tail, magnetic monitoring measurements in the geostationary orbit and at certain ground based stations are important elements concerning improving such techniques.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 441-445
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  • 10
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    Ionospheric modeling at Air Force Global Weather Central (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The four Dimensional Ionospheric Model (4-D) is described. The 4-D integrates a wide variety of ionospheric data types into a consistent ionospheric specification. At each observing location, the 4-D reduces an entire electron density profile to four weighting coefficients. These weighting coefficients are interconnected in time and space by spectral analysis techniques. The resultant field of spectral coefficients can be used to reconstruct an electron density profile at any latitude, longitude and time.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 367-377
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  • 11
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    Geophysical forecasting at AFGWC (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Methods for forecasting the state of the space environment, Sun, interplanetary field, magnetosphere, and ionosphere are discussed. Areas requiring scientific advancements to support the increasing operational requirements of systems that use or are affected by the environment above 50 km are identified.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 350-366
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  • 12
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    A weekly ionospheric index (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The monthly and weekly T indices are discussed. Some possibilities for improving the reliability of the weekly T index are considered, including extending its applicability to daily variations of the global ionosphere.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 279-287
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  • 13
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    A review of the operation of the IUWDS Regional Warning Centre at the Ionospheric Prediction Service, Sydney (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The operation of the Sydney Regional Warning Centre is reviewed. Routine data reports are issued daily, while disturbance warnings (short-term forecasts) are issued as necessary. An outline of the methods used in forecasting solar activity and geomagnetic disturbances is given.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 229-238
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  • 14
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    A disturbance forecaster's view of the September 1977 events (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The solar-geophysical events of 1977 September 7-26 are presented. A variety of disturbance forecasting problems, viz, disc transit of a center of activity with high microwave flux but relatively low meter-wave flux, flares in this region near east limb, central meridian, and west limb with major radio events, and the presence of two coronal holes, were observed. The Sydney daily GEOSYD message and IPS Disturbance Warnings issued during this period are related to the solar geophysical data available, at the time, about these events.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 239-248
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  • 15
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    Forecasting ionospheric and geomagnetic conditions at the IAG forecasting center (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: A description of the Moscow Regional Warning Center activity in the field of geomagnetic and ionospheric forecasting is presented.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 104-117
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  • 16
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    A simplified indexing of F-region geophysical noise at low latitudes (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: A simple method of deriving an F-region index that can warn the prediction users at low latitudes as to the specific months when they have to be more careful in using the long term predictions is described.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 134-139
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  • 17
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    A method of predictions geomagnetic activity based on a coronal model of relations between solar and geomagnetic activities (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A method developed to predict both disturbed and quiet geomagnetic periods is described. The method uses solar situations along the CM with the key role of filaments, giving indirect evidence of types of directly unobservable coronal structures above them. The time lag, not to be interpreted in terms of propagation speed, between the CM activity and the commencement of the geomagnetic response is about one to two days. Solar phenomena serve as indicators within approximately 10 deg of the CM and up to the zone of high latitude filaments.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 44-60
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  • 18
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    The communications industry's requirements and interests (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: Of interest to the communications industry are the amplitude, waveshape, duration and frequency of lightning-originated voltage surges and transients on the communications network, including the distribution system and AC power supply circuits. The cloud-to-ground lightning discharge and its characteristics are thought to be most meaningful. Of specific interest are peak current, waveshape, number of flashes, strokes per flash, and zone of influence. Accurate and meaningful lightning data at the local level (telephone district office) is necessary for a decision on the appropriate protection level. In addition to lightning, the protection engineer must consider other factors such as: AC induction, switching surges, ground potential rise, soil resistivity, bonding and grounding techniques, shielding and isolation, and exposure of the telephone loop.
    Keywords: GEOPHYSICS
    Type: Proc.: Workshop on the Need for Lightning Observations from Space; p 115-125
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  • 19
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    The state of technology in electromagnetic (RF) sensors (for lightning detection) (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: A brief overview of the radio-frequency sensors which were applied to the detection, isolation, and/or identification of the transient electromagnetic energy (sferics) radiated from one or more lightning discharges in the atmosphere is presented. Radio frequency (RF) characteristics of lightning discharges, general RF sensor (antenna) characteristics, sensors and systems previously used for sferic detection, electromagnetic pulse sensors are discussed. References containing extensive bibliographies concerning lightning are presented.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 88-109
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  • 20
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    Lightning hazards overview: Aviation requirements and interests (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: A ten-year history of USAF lightning incidents is presented along with a discussion of the problems posed by lightning to current aircraft, and the hazards it constitutes to the electrical and electronic subsystems of new technology aircraft. Lightning technical protection technical needs, both engineering and operational, include: (1) in-flight data on lightning electrical parameters; (2) tech base and guidelines for protection of advanced systems and structures; (3) improved laboratory test techniques; (4) analysis techniques for predicting induced effects; (5) lightning strike incident data from general aviation; (6) lightning detection systems; (7) pilot reports on lightning strikes; and (8) better training in lightning awareness.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 126-135
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  • 21
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    State of technology in optical systems (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The use of silicon photodiode sensors and locator systems for lightning experiments is discussed. Tables are presented on: (1) satellite optical lightning experiments (silicon detectors); (2) reticon photodiode linear arrays; and (3) locator systems (grey code and reticon). An illustration of a grey code locator system for a low altitude satellite is also given.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 81-87
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  • 22
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    A review of satellite lightning experiments (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: Over the past five years a series of satellite optical experiments were conducted to investigate terrestrial lightning. These experiments were designed to gather statistical information about the optical waveform of lightning, measure occurrence rates, demonstrate the feasibility of detecting lightning from space platforms, and study possible applications for satellite lightning sensors. These experiments are reviewed. Some of the results are presented, and some ideas for future satellite systems are discussed.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 61-80
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  • 23
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    Areas where solar-terrestrial coupling may influence or be influenced by the middle atmosphere (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The nature of the wave interactions, particularly those induced by transient solar and geomagnetic phenomena is discussed. Solar activity which includes modulations of galactic cosmic ray flux reaching Earth is discussed. Coupling processes involving charged particles and atmospheric electric structure are presented.
    Keywords: GEOPHYSICS
    Type: Middle Atmosphere Electrodyn.; p 219-249
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  • 24
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    Energy and mass transport in the thermosphere (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: Examples illustrating the effects of large scale energy and mass transport in the thermosphere discussed include: (1) The seasonal variations reveal temperature, composition, and ionospheric anomalies involving energy exchange between the thermosphere and mesosphere. (2) The midnight temperature maximum in the thermosphere is interpreted as a signature of tidal waves emanating from the mesosphere and momentum coupling associated with ion drag. (3) The ionospheric storm in the F region illustrates the intricate effects of large scale atmospheric winds driven by magnetospheric energization processes. (4) Atmospheric signatures of Joule heating and electric field momentum coupling are markedly different.
    Keywords: GEOPHYSICS
    Type: Middle Atmosphere Electrodyn.; p 169-202
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  • 25
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    Middle atmosphere electrodynamics: Report of the Workshop on the Role of the Electrodynamics of the Middle Atmosphere on Solar Terrestrial Coupling (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The middle atmosphere (MA), which is defined as the region bounded below by the tropopause near 10 km and above by the mesopause near 90 to 100 km, is regarded as a passive medium through which electric fields and currents are transmitted from sources above and below. A scientific background is given for: sources of MA electric fields; MA conductivity and currents; and MA plasma characteristics. Recommendations are given for research in MA electrodynamics in the following areas: (1) MA electrodynamical parameters; (2) models and supportive laboratory measurements; and (3) investigation of specific problems in the coupled systems.
    Keywords: GEOPHYSICS
    Type: Middle Atmosphere Electrodyn.; p 1-25
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  • 26
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    Forecasts of geomagnetic activity by Ottawa Magnetic Observatory: Their reliabilty and application (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: A 27 day forecast of geomagnetic activity based on the forecasts from two locations is presented. To evaluate the reliability of the forecasts, the predicted activity was compared with the actual geomagnetic activity at five geomagnetic observatories located in different magnetic zones: Ottawa (57.0N, 351.5E); Meanook (61.8N, 301.0E); Fort Churchill (68.8N, 322.5E); Cambridge Bay (76.7N, 294.0E); and Resolute Bay (83.1N, 287.7E). Results indicate that the percentage of correct predictions varies with the geomagnetic latitude of the observatory used for comparison. The percentage is on the average highest for lower latitude stations and lowest for the northern stations. The number of incorrect predictions ranges from 4.7% for Ottawa to 8.4% for Churchill.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 398-405
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  • 27
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    Prediction limits for foF2 (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Some of the factors limiting the prediction of foF2 are investigated using median and hourly foF2 values recorded at stations in the Australian ionosonde network. Different time and spatial scales together with different levels of solar and geomagnetic activity are considered. All data used in the analysis are displayed in a series of scatter diagrams which provide an overall view of the accuracy limits for foF2 predictions.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 259-278
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  • 28
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    The geographical distribution of lightning: Forestry and range requirements and interests (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: In an attempt to reduce the response time of the initial attack forces to lightning-caused fire, a lightning detection system that effectively locates accurate directions to lightning discharges to over 200 miles from the detection equipment was developed. The system was first tested in Alaska in 1975. Since that time, further development and operational testing led to the implementation of wide area networks. For the 1979 fire season an eight station network in Alaska is to be implemented that will cover virtually all of the lightning-caused fire areas in the state. In the western United States, an eighteen station network that will cover approximately 85% of eleven states is to be implemented. For the first time, large scale ground discharge lightning distribution information is to be available.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 110-114
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  • 29
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    Lightning properties and associated emissions (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: A brief overview of the lightning observables and environment is provided. A selective review is presented of those properties of lightning which might be useful as space observables.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 25-60
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  • 30
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    Ion chemistry of the middle atmosphere (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: Difficulties in making in situ and laboratory measurements of the ion composition of the middle atmosphere are related. An approach is presented which extends theoretical and laboratory results for both negative and positive ions from the D-region down to the stratosphere. In each case, the extension of data from the D-region 'down' to the higher pressure stratosphere is primarily a matter of inquiring into the role of the minor constituents whose absolute concentrations become large enough to allow them to become involved in the ion chemistry.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 71-88
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  • 31
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    Solar-terrestrial coupling through atmospheric electricity (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: There are a number of measurements of electrical variations that suggest a solar-terrestrial influence on the global atmospheric electrical circuit. The measurements show variations associated with solar flares, solar magnetic sector boundary crossings, geomagnetic activity, aurorae, differences between ground current and potential gradients at high and low latitudes, and solar cycle variations. The evidence for each variation is examined. Both the experimental evidence and the calculations made with a global model of atmospheric electricity indicate that there is solar-terrestrial coupling through atmospheric electricity which operates by altering the global electric current and field distribution. A global redistribution of currents and fields can be caused by large-scale changes in electrical conductivity, by alteration of the columnar resistance between thunderstorm cloud tops and the ionosphere, or by both. If the columnar resistance is altered above thunderstorms, more current will flow in the global circuit, changing the ionospheric potential and basic circuit variables such as current density and electric fields. The observed variations of currents and fields during solar-induced disturbances are generally less than 50% of mean values near the earth's surface.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 89-139
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  • 32
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    Direct energy inputs to the middle atmosphere (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: As a working definition of the extent of the middle atmosphere (MA), the height range from 30 to 100 km was adopted. The neutral and ionic composition and the dynamics within this height range are, for the most part, poorly understood. From available information, the importance of various particle and photon energy sources, including their variability, for ionization of the neutral atmosphere in this height range is assessed. The following topics are discussed: (1) penetration of the MA by particle and electromagnetic energy; (2) ionization sources for the MA; (3) galactic cosmic rays; (4) solar H Ly alpha, other EUV, and X-rays; (5) magnetospheric electrons and bremsstrahlung X-rays; and (6) solar cosmic rays.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 43-70
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  • 33
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    Magnetosphere-ionosphere interactions (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The present understanding of magnetosphere ionosphere interactions is described, and present and future predictive capabilities are assessed. Ionospheric features directly coupled to the magnetosphere to a significant degree are considered, with emphasis given to those phenomena of major interest to forecasters and users.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 476-493
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  • 34
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    Energetic solar particle behaviour in the magnetosphere (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The behavior of energetic solar flare particles in the magnetosphere is discussed. In the absence of magnetospheric motion, the problem of particle transport can be treated as simple propagation of charged particles in a stationary magnetic field configuration using, for instance, trajectory calculations in model fields. This single particle approach is the basis for the determination of intensity and anisotropy structures over the polar caps and in the geomagnetic tail from different interplanetary conditions. Particle transport on closed field lines is in addition strongly affected by resonant interaction processes as pitch angle scattering and radial diffusion.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 446-463
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    Short term magnetospheric particle variations (1 minute T 1 day), appendix 1 (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: A schematic representation of the generation and propagation processes for energetic particles of concern in solar terrestrial predictions is given. Particle precipitation at low, mid, and high altitudes is discussed with emphasis on prediction techniques. Methods given for testing of such techniques include traditional collaborations, enhanced collaborations, simulated prediction schemes, and field tests.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 433-440
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    The prediction of AE, ap, and Dst at time lags between 0 and 30 hours (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The magnetic activity indexes AE, ap, and Dst are correlated with approximately 35,000 hours of interplanetary plasma and magnetic field measurements acquired near the Earth (assembled by NASA/NSSDC into a composite data sat). Lag times between the indexes and solar wind parameters ranged from 0 to 30 hours. Correlations at lags less than 6 hours yield results in agreement with previous studies. At greater lags, the correlation coefficients between the solar wind parameters and AE and ap approach these parameters' autocorrelation (persistence) values. For Dst the correlation with solar wind parameters is lower than that with AE and ap in the 3 to 4 hour lag range whereas the autocorrelation of Dst is significantly higher over the entire 0 to 30 hour lag range. The implications of these differences between AE, ap, and Dst are discussed in terms of persistence of solar wind structure.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 399-414
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    Dosimetry in the manned space program (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Dosimetric results of the various U.S. manned spaceflight programs are presented along with a description of the instrumentation, trapped radiation environments, and spacecraft shielding models. Analytical dose calculations are included and composed with actual measurements. Future requirements of the solar-terrestrial data user who will support manned spaceflight operations during the space shuttle era are outlined.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 121-132
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    Predictability of upper-atmospheric density and composition (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: Empirical models of upper-atmospheric density and composition are employed in a number of areas, ranging from basic research in atmospheric and ionospheric physics to practical applications in satellite ephemeris prediction. Such models are based on various kinds of data sets and have varying levels of complexity, strengths, and weaknesses. The characteristics of several of the widely used models are described and studies in which the predictions of these models were compared with observational data are reviewed. The relative advantages and limitations of the models in current use are discussed as well as ways in which the models might be improved.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 71-88
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    Low energy magnetospheric plasma interactions with space systems: The role of predictions (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The present status of low energy magnetospheric plasma interactions with space systems is reviewed. The role of predictions in meeting user needs in assessing the impact of such interactions is described. In light of the perceived needs of the user community and of the current status of modeling and prediction efforts, it is suggested that for most user needs more detailed statistical models of the low energy environment are required. In order to meet current prediction requirements, real-time in situ measurements are proposed as a near-term solution.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 36-70
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    Modeling the Earth's radiation belts. A review of quantitative data based electron and proton models (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-16
    Description: The evolution of quantitative models of the trapped radiation belts is traced to show how the knowledge of the various features has developed, or been clarified, by performing the required analysis and synthesis. The Starfish electron injection introduced problems in the time behavior of the inner zone, but this residue decayed away, and a good model of this depletion now exists. The outer zone electrons were handled statistically by a log normal distribution such that above 5 Earth radii there are no long term changes over the solar cycle. The transition region between the two zones presents the most difficulty, therefore the behavior of individual substorms as well as long term changes must be studied. The latest corrections to the electron environment based on new data are outlined. The proton models have evolved to the point where the solar cycle effect at low altitudes is included. Trends for new models are discussed; the feasibility of predicting substorm injections and solar wind high-speed streams make the modeling of individual events a topical activity.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 21-35
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    Space vehicle meteoroid shielding design (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Design principles of spaced, multiwall meteoroid protection are investigated in the light of experimental data generated during the Apollo Program. The outer wall or shield is shown to be the most important element in the meteoroid-spacecraft interaction. The condition of the debris is primarily a function of the shock pressure, the melting points of the meteoroid and the shield, and the length of the meteoroid and thickness of the shield. Spacing between the walls is effective up to approximately 100 times the length of the meteoroid. The required thickness of the second wall is shown to be proportional to the meteoroid mass, velocity, and density, and to the spacing between the walls, taken with exponents dependent upon the condition of the debris. The effects of placing additional elements (insulation or honeycomb cells) between the two walls are discussed, and the efficiency of various protective configurations is presented. An analysis of the meteoroid protection proposed for the Comet Halley probe is included as an appendix.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: ESA Comet Halley Micrometeoroid Hazard Workshop; p 85-92
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    Predictions of the Space Environment Services Center (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: The types of users of the Space Environment Services Center are identified. All the data collected by the Center are listed and a short description of each primary index or activity summary is given. Each type of regularly produced forecast is described, along with the methods used to produce each prediction.
    Keywords: GEOPHYSICS
    Type: Solar-Terrest. Predictions Proc., Vol. 1; p 322-349
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    The use of ionospheric indices to make real- and near-real-time forecasts of foF2 around Australia (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: Two computer programs are used to forecast foF2 at points around Australia from daily and hourly ionospheric indices. It is found that for forecasts one day ahead, the most accurate results are obtained using the past variations of foF2 at several stations to determine a latitudinal-average daily ionospheric index. Forecasts made with lead times of zero to three hours do not offer significant improvements over those made one day ahead.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Prediction Proc., Vol. 1; p 249-258
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    KAZIA: A computer system for solar-terrestrial data processing and objective prediction (1979)
    In:  CASI
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    Publication Date: 2006-01-16
    Description: A computer system for solar terrestrial data processing is described. The data base consists mainly of information contained in Ursigrams exchanged between the IUWDS Regional Warning Centers. The system structure and its functions are presented. Solar flare forecasting is described, as one of the prediction techniques incorporated in the system.
    Keywords: GEOPHYSICS
    Type: NOAA Solar-Terrest. Predictions Proc., Vol. 1; p 61-66
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    The atmospheric electric global circuit (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The hypothesis that world thunderstorm activity represents the generator for the atmospheric electric current flow in the earth atmosphere between ground and the ionosphere is based on a close correlation between the magnitude and the diurnal variation of the supply current (thunderstorm generator current) and the load current (fair weather air-earth current density integrated over the earth surface). The advantages of using lightning survey satellites to furnish a base for accepting or rejecting the thunderstorm generator hypothesis are discussed.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Proc.: Workshop on the Need for Lightning Observations from Space; p 136-147
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    Mining and beneficiation of lunar ores (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The beneficiation of lunar plagioclase and ilmenite ores to feedstock grade permits a rapid growth of the space manufacturing economy by maximizing the production rate of metals and oxygen. A beneficiation scheme based on electrostatic and magnetic separation is preferred over conventional schemes, but such a scheme cannot be completely modeled because beneficiation processes are empirical and because some properties of lunar minerals have not been measured. To meet anticipated shipping and processing needs, the peak lunar mining rate will exceed 1000 tons/hr by the fifth year of operation. Such capabilities will be best obtained by automated mining vehicles and conveyor systems rather than trucks. It may be possible to extract about 40 kg of volatiles (60 percent H2O) by thermally processing the less than 20 micron ilmenite concentrate extracted from 130 tons of ilmenite ore. A thermodynamic analysis of an extraction process is presented.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Space Resources and Space Settlements; p 275-288
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    A geologic assessment of potential lunar ores (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: Although bulk lunar soil is not a suitable feedstock for extracting metals, certain minerals such as anorthite and ilmenite can be separated and concentrated. These minerals can be considered as potential ores of aluminum, silicon, titanium, andiron. A separation and metal extraction plant could also extract large amounts of oxygen and perhaps hydrogen from these minerals. Anorthie containing 19 percent aluminum and 20 percent silicon can be concentrated from some highland soils where it is present in amounts up to 60 percent. Ilmenite containing 32 percent titanium and 37 percent iron can be concentrated from some mare soils where it is present in amounts up to 10 percent. The ideal mining site would be located at the boundary between a high-titanium mare and a high-aluminum highlands. Such area may exist around the rims of some eastern maria, particularly Tranquilitatis. A location on Earth with raw materials as described above would be considered an economically valuable ore deposit if conventional terrestrial resources were not available.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: NASA. Ames Res. Center Space Resources and Space Settlements; p 243-255
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    Tropospheric electrification (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The solid Earth carried a negative charge of approximately 10 C to the 6 th power and the lower atmosphere an equal, opposite charge. While a number of charging processes in the lower atmosphere are involved, such as erupting volcanoes, snow, sand and dust storms, and the bubbles bursting from the oceans, the primary cause of the Earth's electrification is activity of thunderstorms. Although it is known that the electrification of these clouds is caused by the accumulation of regions of charged water particles, there is no general agreement concerning which process is the cause of the electrification within the cloud and what role this electrification plays in the meteorological processes that take place in the lower atmosphere. The development of thunderclouds and the electric fields and currents above them are discussed.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 157-168
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    Electric generators in the magnetosphere-ionosphere system (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: The nature and cause of electric fields in the coupled magnetosphere-ionosphere system and their effects in the middle atmosphere are discussed. Electric fields induced by the solar wind are reported. The equivalence between forces and electric currents and also between current closure and stress balance is described. The motions of the magnetospheric and ionospheric fluids and the electric fields of interest were determined by the balance of these forces, or equivalently by the closure of the currents. The physical nature of stresses and currents was examined.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 203-217
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    Tropospheric effects on the middle atmosphere and vice-versa (1979)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The mechanisms by which phenomena occurring in the troposphere can affect that atmospheric region lying above the tropopause and below the mesopause are discussed as well as mechanisms by which middle atmospheric phenomena affect the tropospheric circulation, and how the middle atmosphere may act as a medium by which extraterrestrial effects may give rise to changes in tropospheric circulation. Energetics and external energy sources are considered. Aspects of vertical coupling examined include upward, downward, radiational, chemical, and electrical modes.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 141-156
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    The middle atmosphere (1979)
    In:  CASI
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    Publication Date: 2006-01-12
    Description: A quick introduction to some of the important electrical properties, and to the factors that influence them and their variability are provided. The following topics are discussed: (1) production of ionization; (2) ion concentration; (3) ion composition; and (4) variability of the various sources of middle atmospheric ionization.
    Keywords: GEOPHYSICS
    Type: NASA. Goddard Space Flight Center Middle Atmosphere Electrodyn.; p 27-42
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    Sample fields of the Viking landers, physical properties, and aeolian processes (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Surface sampler activities on Mars during the Viking extended mission are considered, including excavation of deep trenches, construction of conical piles of materials, backhoe touchdown experiments, and acquisition of contiguous pictures of the surface beneath number 2 terminal descent engines using mirrors. Results of the Physical Properties Investigation that are relevant to aeolian processes are also discussed. Both pictures and surface sampler data indicate that the surface materials in the sample fields of the Viking landers may be grouped, in order of increasing strength, into drift material, crusty to cloddy material, blocky material and rocks.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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    Pitted and fluted rocks in the Western Desert of Egypt - Viking comparisons (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Western Desert of Egypt is one of the most arid regions on earth and is probably the closest terrestrial analog to the surface of Mars. An expedition to the area in 1978 revealed an abundance of quartzite and basalt rocks that have been pitted and fluted by wind erosion and deflation of the desert surface. These pitted rocks are internally homogeneous, show no internal holes or vesicles, and are considered an important but neglected type of ventifact. They bear a striking resemblance to the pitted and fluted rocks seen by the Viking Landers, rocks that have generally been interpreted as vesicular basalts only slightly modified by wind erosion. Wind tunnel studies of the air flow over and around nonstreamlined hand specimens from the Western Desert show that windward abrasion coupled with negative flow, secondary flow, and vorticity in a unidirectional wind can explain the complex arrays of pits and flutes. These field and laboratory observations suggest that the pitted rocks at the Viking Lander sites are also ventifacts, and thus the Martian surface may be far more wind eroded than previously thought.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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    Morphology and distribution of common 'sand' dunes on Mars - Comparison with the earth (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A comparative study of Martian and terrestrial dunes was made based on Viking Orbiter pictures and aerial pictures of terrestrial deserts. The morphological similarity between the Martian dunes and terrestrial crescentic dunes implies that the dynamics of dune formation are similar on the two planets, despite Martian constraints on dune formation that include much higher velocity winds required to move 'sand' in saltation, the possible inhibition of sand movement by absorbed water vapor, the seasonal 'snow' cover in the north circumpolar erg, and a probably sparse sand supply. The absence of longitudinal dunes and the restriction of massive crescentic dunes to a few sites on Mars suggests that Mars may have a long eolian history in which much of the sand suitable for saltation has already been transported to the north polar erg and crater floor fields.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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    Viking magnetic properties experiment - Extended mission results (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The backhoe magnets on Viking Lander (VL) 2 were successfully cleaned, followed by a test involving successive insertions of the cleaned backhoe into the surface. Rapid saturation of the magnets confirmed evidence from primary mission results that the magnetic mineral in the Martian surface is widely distributed, most probably in the form of composite particles of magnetic and nonmagnetic minerals. An image of the VL 2 backhoe taken via the X4 magnifying mirror demonstrates the fine-grained nature of the attracted magnetic material. The presence of maghemite and its occurrence as a pigment in, or a thin coating on, all mineral particles or as discrete, finely divided and widely distributed crystallites, are consistent with data from the inorganic analysis experiments and with laboratory simulations of results of the biology experiments on Mars.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Dec. 30
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    Primordial heating of asteroidal parent bodies (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Most meteorites show evidence of thermal processing either because of metamorphic changes or as a result of melting and differentiation. Proposed mechanisms for supplying this energy generally rely upon short-lived radioisotopes or electrical induction, though accretion is sometimes mentioned, and more exotic models have been discussed. Interest in isotopic heating has been heightened by the discovery of Al-26 in Allende inclusions and also by the proposal that a lunar core and dynamo resulted from the radioactive decay of superheavy elements during the early solar system. Electrical induction as a heat source can be scaled to a broad range of solar system conditions, but corroborative evidence for these conditions is inconclusive. The accretion mechanism is probably not viable for the asteroidal and meteorite parent bodies, because the high kinetic energy requirement is inconsistent with the formation of the objects and their regoliths in the presence of a weak gravitational field.
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    Aqueous activity on asteroids - Evidence from carbonaceous meteorites (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Carbonaceous chondrites of groups CI and CM were formed by impact brecciation and aqueous alteration of earlier generations of mineral phases within the surface regions of two or more parent bodies. Those parent bodies were probably asteroids, rather than comets, although a problem still exists in delivering such material safely to earth. Aqueous activity may have been widespread on asteroids.
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    Diverse puzzling asteroids and a possible unified explanation (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Recent observations have led to unconventional models of certain asteroids, suggesting previously unsuspected forms. Some of these include binary asteroids (e.g., 532 Herculina, 18 Melpomene), very irregular asteroids (e.g., the Mars-crossing 1580 Betulia), and very elongated asteroids, unlikely to be collisional fragments (e.g., 624 Hector). A connection is suggested between this observational work and ongoing theoretical work concerning collisions of large comparable-sized asteroids. Such collisions have different consequences from the collisions usually considered. The new work suggests possible sources of elongated and binary asteroids.
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    Radio observations of asteroids - Results and prospects (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Radio observations of the asteroids can provide information on the thermal and dielectric properties of the surface materials and, because the radio emission arises somewhat below the surface, the data give some indication of layering. Observational difficulty has limited the investigations to only 6 asteroids. 1 Ceres and 324 Bamberga appear to have a layer of dust covering a more compacted material; the data on 4 Vesta cannot be matched by any current models for the surface; and the results for 18 Melpomene, 31 Euphrosyne and 433 Eros are too incomplete for firm conclusions. Future possibilities include more accurate radiometry of a few selected asteroids of different taxonomic classes and actual resolution of some of the larger objects by aperture synthesis techniques.
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    Optical polarimetry of asteroids and laboratory samples (1979)
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    Publication Date: 2011-08-17
    Description: Interpretations of astronomical polarization data for more than 100 minor planets are summarized with reference to laboratory data for lunar, meteoritic, and terrestrial samples. All observed asteroids, including objects only a few kilometers in diameter, have microscopically intricate surfaces. Detailed comparisons between laboratory measurements of basaltic achondrites and telescopic results for Vesta show that its surface is particulate with a broad range of particle sizes, including a component of fine (1-5 micron) dust. The surface soils have not, however, undergone marked optical alterations as is the case for the lunar fines. For albedos greater than about 0.06, the albedo and hence the diameter can be determined with some reliability from the slope of the ascending branch of the polarization-phase curve. Many minor planets have surfaces that are remarkably uniform in albedo and texture on a hemispheric scale. A notable exception is 4 Vesta, which shows about ten percent albedo variegation between hemispheres.
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    The asteroids - Nature, interrelations, origin, and evolution (1979)
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    Publication Date: 2011-08-17
    Description: The paper deals with the physical and chemical nature of the asteroids and with their physical and orbital distributions and interrelationships. Existing hypotheses about the formation and evolution of asteroids are examined. A thematic synopsis of these topics is presented, and accepted interpretations are discussed.
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    Review of the metallographic cooling rates of meteorites and a new model for the planetesimals in which they formed (1979)
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    Publication Date: 2011-08-17
    Description: The cooling rates of meteorites through approximately 900 -650 K, as read from their metal alloy compositions, are reviewed. Metallographic cooling rates are compared with the cooling rates that appear to be required by the K/Ar and Ar-40/Ar-39 ages of five meteorite classes, and discrepancies are found in all cases. Either (1) the metallographic cooling rates (and also Pu-244 fission cooling rates) are systematically in error, being too slow by a factor of approximately 6; or (2) the traditional thermal model for parent meteorite planets (having constant dimension and uniform physical properties) is oversimplified and the Ar closure temperatures for chondrites derived by Turner et al. (1978) are too low. An alternative parent planet model is proposed and numerically modeled, in which accretion of thermally insulating particulate matter, heat generation by Al-26 decay, melting or sintering of the particulate matter into conductive rock, and establishment of the properties of the meteorites occurred concurrently. Meteorite chronologies are somewhat easier to understand in this context, since the initially small, hot (thus sintered and conductive) bodies would have cooled rapidly to isotopic closure, but later cooling might have been much slower as a result of the continued accretion of insulating particulate matter.
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    Asteroid taxonomy and the distribution of the compositional types (1979)
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    Publication Date: 2011-08-17
    Description: Physical observations of minor planets documented in the TRIAD computer file are used to classify 752 objects into the broad compositional types C, S, M, E, R, and U (unclassifiable) according to the prescriptions adopted by Bowell et al. (1978). Diameters are computed from the photometric magnitude using radiometric and/or polarimetric data where available, or else from albedos characteristic of the indicated type. An analysis of the observational selection effects leads to tabulation of the actual number of asteroids, as a function of type and diameter, in each of 15 orbital element zones. For the whole main belt the population is 75% of type C, 15% of type S, and 10% of other types, with no belt-wide dependence of the mixing ratios on diameter. In some zones the logarithmic diameter-frequency relations are decidedly nonlinear. The relative frequency of S-type objects decreases smoothly outward through the main belt, with exponential scale length 0.5 AU. The rarer types show a more chaotic, but generally flatter, distribution over distance. Characteristic type distributions, contrasting with the background population, are found for the Eos, Koronis, Nysa and Themis families.
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    Phobos and Deimos - A preview of what asteroids are like (1979)
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    Publication Date: 2011-08-17
    Description: The surfaces of Phobos and Deimos are discussed, as the best available examples of what asteroid surfaces may be like. Attention is given to shape, regolith properties, crater densities, albedo markings and surface gravities. It is found that although the surfaces of these two similarly-sized asteroid-like bodies are nearly identical in terms of many disk-integrated properties, they are strikingly different in surface morphology.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Radar observations of asteroids (1979)
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    Publication Date: 2011-08-17
    Description: Radar observations of asteroids use simple CW waveforms, the transmissions lasting for the duration of the round-trip delay. The echo is received, spectrum-analyzed, and integrated for a similar period. Since radar coherently illuminates the target, the surface scattering properties at radio wavelengths are directly determined as a function of angle and polarization. The distance and radial velocity obtained with radar complement the angular position of the object as determined from telescope measurements. Radar cross sections, scattering law, and radius are given for radar-observed asteroids.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Masses and densities of asteroids (1979)
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    Publication Date: 2011-08-17
    Description: Ceres, Pallas, and Vesta allow a determination of mass from gravitational effects in the motion of another asteroid. An extended and partly corrected set of observations of 197 Arete leads to an increase of 15% in the resulting mass of Vesta that was first determined by Hertz. Other possibilities of mass determination and estimates of the total mass of asteroids are mentioned. The available diameter determinations and adopt preferred values are reviewed. The densities for Ceres, Pallas, and Vesta are respectively 2.3 plus or minus 1.1 g/cu cm, 2.6 plus or minus 0.9 g/cu cm and 3.3 plus or minus 1.5 g/cu cm.
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    On the origin of asteroids (1979)
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    Publication Date: 2011-08-17
    Description: A general scenario is described for the early history of the solar system. The primitive solar nebula is formed from the infall of gas from a collapsing interstellar cloud fragment. It becomes repeatedly unstable against collapse to form giant gaseous protoplanets. In the course of protoplanet evolution the center of the protoplanet enters a thermodynamic regime in which common rocky minerals become liquids; convection brings solids to the central region where a substantial fraction of them rain out to form a protoplanetary core. In the inner solar system protoplanetary envelopes are tidally stripped away, thus injecting into the solar nebula large equantities of chondrules and inclusions. Late in the development of the solar nebula, after most of the gas has disappeared, turbulence dies out and the small solids settle into a thin layer at midplane of the nebula. Gravitational instabilities in this layer form asteroidal and cometary bodies. Some further consequences of this scenario are discussed.
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    Geochemical evolution of the eucrite parent body - Possible nature and evolution of asteroid 4 Vesta (1979)
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    Publication Date: 2011-08-17
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Infrared spectral reflectances of asteroid surfaces (1979)
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    Publication Date: 2011-08-17
    Description: This review compares the types of compositional information produced by three complementary techniques used in infrared observations of asteroid surfaces: broadband JHKL photometry, narrow band photometry, and multiplex spectroscopy. The high information content of these infrared observations permits definitive interpretations of asteroid surface compositions in terms of the major meteoritic minerals (olivine, pyroxene, plagioclase feldspar, hydrous silicates, and metallic Ni-Fe). These studies emphasize the individuality of asteroid surface compositions, the inadequacy of simple comparisons with spectra of meteorites, and the need to coordinate spectral measurements of all types to optimize diagnostic capabilities.
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    The nature and effects of impact cratering on small bodies (1979)
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    Publication Date: 2011-08-17
    Description: Collisions between asteroids and other forms of solar system debris are discussed, especially relatively high-energy, non-catastrophic collisions, the resulting craters, and the effects they should have on the surfaces and interiors of target bodies. Attention is given to the nature and formation of impact craters, as well as to shock waves and the energy (kinetic, internal) imparted through them, crater scaling, stress wave-surface interactions, impact melt, and the effects of non-escaping ejecta on the surface of the target body (rock, fine-grained regolith, porous media).
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Regolith development and evolution on asteroids and the moon (1979)
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    Publication Date: 2011-08-17
    Description: Early descriptions of regoliths on small bodies were devised to account for observations of asteroids (Chapman 1971, 1976) and the gas-rich meteorites (Anders 1975). Lack of agreement between these approaches prompted Housen et al. (1978, 1979) to examine the problem in detail. The resulting model predicted that moderate-sized (100-300 km) asteroids should evolve regoliths up to a few kilometers deep which could be source regions of gas-rich meteorites. Smaller objects should have regoliths ranging from dust coatings to meters-thick layers depending on the strength of the object. The earlier model could not treat asteroids larger than 300 km in diameter. The model, now modified to treat larger-sized objects, predicts regolith depths, on asteroids larger than 300 km, which decrease with increasing size. A regolith depth of 7 m is predicted for the lunar maria in reasonable agreement with the observed depths of 5 m.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Distant asteroids and outer Jovian satellites (1979)
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    Publication Date: 2011-08-17
    Description: Sixty percent of the sampled objects in the Hilda, Trojan and outer Jovian satellite locations belong to C-type and another 30% belong to a new group called RD-type (reddish and dark), sometimes referred to simply as D-type. Objects in this group have low albedo values between 2 and 4% and steep reflection spectra between 0.7 micron and 0.9 micron. Furthermore, 944 Hidalgo belongs to this group but shows color variation over its surface. Meteoritic minerals with similar optical reflection spectra are discussed. Trojans with sizes down to 15 km in the cloud preceding Jupiter are about 3.5 times more numerous than those in the following cloud. RD-type Trojans appear more often in the preceding cloud. There is a resemblance of spectrum, albedo and phase relation among the majority of Trojans and the outer Jovian satellites.
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    F-region dynamics (1979)
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    Publication Date: 2011-08-17
    Description: The U.S. research efforts in the last four years, relating to an understanding of upper atmosphere or thermosphere and F-region dynamics are reported. Simultaneous measurements of atmospheric parameters from the Atmosphere Explorer satellites were used in photochemistry and photoenergetics studies. Studies of the magnetosphere as a major source of energy and momentum for the thermosphere are outlined. Time-dependent ionosphere models which describe the thermal structure, composition, photoelectron spectrum, and airglow emissions in F-regions are discussed. Solar tides, magnetic disturbances, and gravity waves in the thermosphere are considered. It is noted that planetary explorations will help to understand scientific problems of the space environment.
    Keywords: GEOPHYSICS
    Type: Reviews of Geophysics and Space Physics; 17; June 197
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    Neutral thermospheric composition and thermal structure (1979)
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    Publication Date: 2011-08-17
    Description: A review of the published experimental works of the past four years is presented. Since 1975, satellite and ground based programs produced new data on the composition and structure of the thermosphere, including the first extensive measurements of a number of minor constituents. The new data were incorporated in a number of semiempirical models which provided an increasingly accurate picture of thermospheric variations. Empirical modelling is considered, followed by solar activity variations, daily variations, magnetic storm variations, measurements of molecular oxygen and minor species, and miscellaneous temperature and density determinations. The concepts of global circulation patterns driven by solar radiation, magnetospheric energy, and momentum sources, and wave sources in the lower atmosphere, and the accompanying redistribution of minor species are outlined.
    Keywords: GEOPHYSICS
    Type: Reviews of Geophysics and Space Physics; 17; June 197
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    The Moho as a magnetic boundary (1979)
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    Publication Date: 2011-08-17
    Description: Magnetism in the crust and the upper mantle and magnetic results indicating that the seismic Moho is a magnetic boundary are considered. Mantle derived rocks - peridotites from St. Pauls rocks, dunite xenoliths from the Kaupulehu flow, and peridotite, dunite, and eclogite xenoliths from Roberts Victor and San Carlos diatremes - are weakly magnetic with saturation magnetization values from 0.013 emu/gm to less than 0.001 emu/gm which is equivalent to 0.01 to 0.001 wt% Fe304. Literature on the minerals in mantle xenoliths shows that metals and primary Fe304 are absent, and that complex Cr, Mg, Al, and Fe spinels are dominant. These spinels are non-magnetic at mantle temperatures, and the crust/mantle boundary can be specified as a magnetic mineralogy discontinuity. The new magnetic results indicate that the seismic Moho is a magnetic boundary, the source of magnetization is in the crust, and the maximum Curie isotherm depends on magnetic mineralogy and is located at depths which vary with the regional geothermal gradient.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 6; July 197
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    Rb-Sr age of the Shergotty achondrite and implications for metamorphic resetting of isochron ages (1979)
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    Publication Date: 2011-08-17
    Description: The age of the Shergotty achondrite is determined by Rb-Sr isotope analysis and the metamorphic resetting of isochron ages, which is presumed to have occurred during a shock event in the history of the meteorite, is discussed. The isochron best fitting the Rb-Sr evolution diagram is found to correspond to an age of 165 million years, with an initial Sr-87/Sr-86 value of 0.72260. Different apparent ages obtained by the K-Ar and Sm-Nd methods are interpreted in terms of a model which quantifies the degree of resetting of internal isochron ages by low temperature solid state diffusion. On the basis of these considerations, it is concluded that Shergotty crystallized from a melt 650 million years ago, was shock heated to 300 to 400 C after its parent body was involved in a collision 165 million years ago, and was first exposed to cosmic rays two million years ago.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geochimica et Cosmochimica Acta; 43; July 197
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    Base line estimation using single passes of laser data (1979)
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    Publication Date: 2011-08-17
    Description: The laser data of the GEOS 3 satellite passes observed by four stations at Greenbelt (Maryland), Bermuda, Grand Turk Island (Bahamas) and Patrick Air Force Base (Florida), were employed to determine precise interstation base lines and relative heights in short orbital arcs of no more than 12-min duration. No more than five arcs of data are required to define the interstation base lines to 30-cm precision. Base lines running parallel to the orbital motion can be defined to submeter precision from a single short arc of data. Combining arcs of different orbital geometry in a common adjustment of two or more stations relative to the base station helps to compensate for weak base line definition in any single arc. This technique can be used for tracking such spacecraft as Lageos, a high-altitude retroreflector-carrying satellite designed for precise laser ranging studies.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 84; July 30
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    Voyager spacecraft radio observations of Jupiter - Initial cruise results (1979)
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    Publication Date: 2011-08-17
    Description: Low frequency (below 1326 kHz) observations of Jupiter obtained from November, 1977 through June, 1978 by the radio astronomy receivers carried by the two Voyager spacecraft are reported and compared with a large body of higher-frequency ground-based observations. Although the morphology of hectometric wavelength (HOM) emissions strongly resembles that of decametric (DAM) wavelength radio noise, they display opposite polarization. DAM emissions are strongly modulated by Io, whereas HOM emissions exhibit little or no influence from any satellite and appear to be modulated by the rotation phase of the planet. Several single-source models could possibly account for these results, including a model assuming emission at two well-separated frequencies above and below the local electron plasma frequency and the model proposed by Barbosa (1976) in which electrostatic waves at twice the upper hybrid frequency couple to both the ordinary and extraordinary electromagnetic modes. However, neither of these is entirely satisfactory.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Geophysical Research Letters; 6; June 197
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  • 79
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    Ozone and temperature trends associated with the 11-year solar cycle (1979)
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    Publication Date: 2011-08-17
    Description: Evidence is presented which suggests that trends in the ozone concentration and stratospheric temperature, reported between the early 1960's and 1976, are to a large extent due to solar ultraviolet flux variability associated with the 11-year solar cycle. Radiative-convective-photochemical simulations of ozone and temperature variations have been made with a solar ultraviolet flux variability model. Results for temperatures and ozone concentrations, when compared with published data, show good agreement.
    Keywords: GEOPHYSICS
    Type: Science; 204; June 22
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    On the average configuration of the geomagnetic tail (1979)
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    Publication Date: 2011-08-17
    Description: A statistical study of the geomagnetic tail has revealed large scale variations in the field configuration both in N-S and E-W directions. The largest value of the B(z) component of the field was observed near the midplane of the tail. Results, such as the discovery of more depolar fields near the flanks of the tail can be incorporated into more realistic models, which should lead to a better understanding of tail behavior. The observed dependence of the tail on interplanetary sector structure may be interpreted in terms of models linking interplanetary field lines to those of the earth.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 84; May 1
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    Auroral origin of medium scale gravity waves in neutral composition and temperature (1979)
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    Publication Date: 2011-08-17
    Description: The kinetic temperature and neutral composition data obtained from the Aeros B neutral atmosphere temperature experiment and the neutral and ion mass spectrometer show spatial structures characteristic of medium scale gravity waves with a wavelength in the range of several hundred kilometers. These waves are associated with auroral activity, and their spatial structure reflects the time history of the auroral electrojet. The medium scale gravity waves tend to propagate to mid-latitudes on the nightside. On the dayside their range is limited to high latitudes. Gravity waves are carriers of auroral energy to middle and low latitudes where they may cause irreversible changes in temperature via viscous dissipation. Since auroral activity occurs frequently, it is suggested that this energy reaches the mid-latitude region of the thermosphere much more frequently than is indicated by planetary magnetic indices.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 84; May 1
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    Magnetic fields in flowing magnetotail plasmas and their significance for magnetic reconnection (1979)
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    Publication Date: 2011-08-17
    Description: A statistical study is made of the magnetic field components that occur in the presence of high-velocity flows. Results are reported for a statistical analysis of 324 intervals of intense bulk plasma flows in the plasma sheet of the geomagnetic tail, measured by the Imp 6 spacecraft. A pronounced tendency for southward fields to be associated with tailward flow more often than with earthward flow yields support for the merging concept, though not in its simplest form. Histograms of 15.36-s averages of vector magnetic field measurements during plasma flows reveal no significant changes in the distribution of beta-y between earthward or tailward plasma flow directions.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 84; May 1
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    Inversion of satellite magnetic anomaly data (1979)
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    Publication Date: 2011-08-17
    Description: A method of finding a first approximation to a crustal magnetization distribution from inversion of satellite magnetic anomaly data is described. Magnetization is expressed as a Fourier series in a segment of spherical shell. Input to this procedure is an equivalent source representation of the observed anomaly field. Instability of the inversion occurs when high frequency noise is present in the input data, or when the series is carried to an excessively high wave number. Preliminary results are given for the United States and adjacent areas.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysics - Zeitschrift fuer Geophysik; 45; 2, 19; 1979
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  • 84
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    Comparison of backscatter ultraviolet /BUV/ and ground-based total ozone fields for December 1970 (1979)
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    Publication Date: 2011-08-17
    Description: For the period December 1970, comparison is made between the monthly average analyses (mapped fields) of the backscatter ultraviolet (BUV) total ozone data and the ground-based observations. In particular, significant differences of over 50 Dobson units are noted over the region of the North Atlantic Ocean with the BUV of greater magnitude than the ground-based data. As part of the overall verification program, both analyses are compared against the 100 mb height fields. The results indicate that the BUV analysis in the region of question is the more consistent of the two.
    Keywords: GEOPHYSICS
    Type: Pure and Applied Geophysics; 117; 3, 19; 1978-197
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    Io - An intense brightening near 5 micrometers (1979)
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    Publication Date: 2011-08-17
    Description: Spectrophotometric observations of the Jovian satellite Io on February 20 and 21, 1978, (Universal Time) were made from 1.2 to 5.4 micrometers. Io's brightness at 4.7 to 5.4 micrometers was found to be three to five times greater at an orbital phase angle of 68 deg than at orbital phase angles of 23 deg (5.5 hours before the brightening) and 240 deg (20 hours after the brightening). Since the 5-micrometer albedo of Io is near unity under ordinary conditions, the observed transient phenomenon must have been the result of an emission mechanism. Although several such mechanisms were examined, the actual choice is not clear.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 16
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    Encounter with Venus (1979)
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    Publication Date: 2011-08-17
    Description: The orbiter and multiprobe components of the Pioneer Venus mission are briefly described. The orbiter was launched on May 20, 1978 and was placed into a highly eccentric near-polar orbit around Venus on December 4, 1978, while the multiprobe was launched on August 8, 1978 and reached Venus on December 9, 1978. Parameters of the orbiter orbit are presented, and modifications of the periapsis altitude are described. The time sequences of the probe entry events are reported for the large probe, north probe, day probe, and night probe, which, along with the bus, are the components of the multiprobe. The multiprobe entry and impact locations as well as related data are reported.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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    Venus upper atmosphere neutral composition - Preliminary results from the Pioneer Venus orbiter (1979)
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    Publication Date: 2011-08-17
    Description: Measurements in situ of the neutral composition and temperature of the thermosphere of Venus are being made with a quadrupole mass spectrometer on the Pioneer Venus orbiter. The presence of many gases, including the major constituents CO2, CO, N2, O, and He has been confirmed. Carbon dioxide is the most abundant constituent at altitudes below about 155 kilometers in the terminator region. Above this altitude atomic oxygen is the major constituent, with O/CO2 ratios in the upper atmosphere being greater than was commonly expected. Isotope ratios of O and C are close to terrestrial values. The temperature inferred from scale heights above 180 kilometers is about 400 K on the dayside near the evening terminator at a solar zenith angle of about 69 deg. It decreases to about 230 K when the solar zenith angle is about 90 deg.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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    Electron temperatures and densities in the Venus ionosphere - Pioneer Venus orbiter electron temperature probe results (1979)
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    Publication Date: 2011-08-17
    Description: The Pioneer Venus orbiter electron temperature probe was used to obtain altitude profiles of electron temperature and density in the ionosphere of Venus. Elevated temperatures at times of low solar wind flux might indicate support for a certain model. According to this model, less than 5% of the solar wind energy is deposited at the ionopause and is conducted downward through an unmagnetized ionosphere to the region below 200 km where electron cooling to the neutral atmosphere proceeds rapidly. The patterns of electron temperatures and densities at higher solar wind fluxes are considered, the variability of the ionopause height in the late afternoon is noted, and the role of an induced magnetic barrier in the neighborhood of the ionopause is discussed.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Science; 203; Feb. 23
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  • 89
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    An evaluation of recent internal field models (1979)
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    Publication Date: 2011-08-17
    Description: The paper reviews the current status of internal field models and evaluates several recently published models by comparing their predictions with annual means of the magnetic field measured at 140 magnetic observatories from 1973 to 1977. Three of the four models studied, viz. AWC/75, IGS/75, and Pogo 8/71, were nearly equal in their ability to predict the magnitude and direction of the current field. The fourth model, IGRF 1975, was significantly poorer in its ability to predict the current field. All models seemed to be able to extrapolate predictions quite well several years outside the data range used to construct the models.
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    A method of evaluating quantitative magnetospheric field models by an angular parameter alpha (1979)
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    Publication Date: 2011-08-17
    Description: The paper introduces an angular parameter, termed alpha, which represents the angular difference between the observed, or model, field and the internal model field. The study discusses why this parameter is chosen and demonstrates its usefulness by applying it to both observations and models. In certain areas alpha is more sensitive than delta-B (the difference between the magnitude of the observed magnetic field and that of the earth's internal field calculated from a spherical harmonic expansion) in expressing magnetospheric field distortions. It is recommended to use both alpha and delta-B in comparing models with observations.
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    CO2 and CO electron vibrational cooling rates (1979)
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    Publication Date: 2011-08-17
    Description: Electron cooling rates for electron vibrational excitation of CO2 and CO and rotational excitation of CO are calculated. Results of the calculation are expressed as closed form analytic relations that are both convenient for numerical calculations and valid over a wide range of electron and neutral temperatures. It is found that the cooling rates and their temperature dependences differ significantly from other calculations. For CO2, these differences are related mainly to the assumptions about the approach to equilibrium and not to the actual cross-section choices. For electron temperatures below 1000 K and gas temperatures near 300 K (representative of conditions in the Venus atmosphere, where collisional cooling of the electrons dominates), the CO2 cooling rate is as much as an order of magnitude larger than previously considered in ionospheric models.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Journal of Geophysical Research; 84; Nov. 1
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  • 92
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    Analysis of star pair latitudes (1979)
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    Publication Date: 2011-08-17
    Description: Star pair latitude observations form the basis for the pole positions reported by the International Polar Motion Service (IMPS). The IPMS processes these observations to produce a mean pole position. However, the time series of observations contains high-frequency information which is lost in the calculation of the mean pole. In this study, 2931 star pair observations are analyzed. A possible large excitation at one cycle per solar day is observed. The average power level in the frequency band of the tesseral tides is seen to be high, although the peaks cannot be conclusively identified as tidal phenomena.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 84; Sept. 10
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    The magnetosphere of Mercury (1979)
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    Publication Date: 2011-08-17
    Description: According to Mariner 10 data on Mercury's magnetosphere, the bow shock and magnetosheath signatures in the magnetic field are entirely consistent with the geometry expected for interaction between a planet-centered magnetic dipole and the solar wind. The geometrically determined distance to the magnetopause stagnation point of solar wind flow was 1.45 plus or minus 0.15 Mercury radii. Comparative scaling of the magnetosphere of Mercury to earth shows that Mercury itself occupies a much larger fraction of the magnetosphere than does the earth. While there is no evidence for the permanent existence of a trapped charged particle radiation belt, intense transient bursts of energetic electrons indicate that a local acceleration process must be active. It is reasonable to assume that this process occurs in the magnetic tail. The interior plasma features compare well with those in the earth's magnetosphere. Characteristic time scales for transient phenomena at Mercury should be reduced by a factor of about 20 in comparison with those on earth - i.e., a few minutes for substorms vs an hour at earth. The origin of the magnetic field is unclear.
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    Planetary geodesy (1979)
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    Publication Date: 2011-08-17
    Description: The results of investigations of the geodesy of the planets and their satellites conducted during the period 1975 - 1978 are surveyed. Analysis of the photographic data of Mercury taken by Mariner 10 have revealed the mass, oblateness, radius rotation period and density of the panet, and allowed the high-resolution mapping of the surface. Earth-based radar imagery has permitted the identification of large-scale topographic features on Venus. Knowledge of the gravitational field of Mars has been improved by Mariner 9 and Viking tracking data, and the global topography and geometric figure of Mars have been derived. Doppler and ranging tracking data from the Viking landers have provided data for the precise determination of Martian rotational dynamics and the topographic features and figures of Phobos and Deimos have been observed. Pioneer 10 and 11 data have yielded information on the mass, gravitational field and dynamic parameters of Jupiter. Discoveries of a satellite of Pluto and a set of rings around Uranus have been made, the rotation of Uranus and Neptune have been measured, and the geodetic properties of the rings and satellites of Saturn have been investigated. Future developments in planetary geodesy are expected from continued Viking data and the Pioneer Venus probe and Voyager probes to Jupiter and Saturn.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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    Cosmic ray ionization of the Jovian atmosphere (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: An approximate form of the Boltzmann equation has been used to obtain local ionization rates due to the absorption of galactic cosmic rays in the Jovian atmosphere. It is shown that the muon flux component of the cosmic-ray-induced cascade may be especially important in ionizing the atmosphere at levels where the total number density exceeds 10 to the 19th per cu cm (well below the ionospheric layers produced by solar EUV). A model containing both positive and negative ion reactions has been employed to compute electron and ion number densities. Peak electron number densities of the order of 1000 per cu cm may be expected even at relatively low magnetic latitudes. The dominant positive ions are NH4(+) and CnHm(+) cluster ions, with n at least 2; it is suggested that the absorption of galactic cosmic-ray energy at such relatively high pressures in the Jovian atmosphere (M about 10 to the 18th to 10 to the 20th per cu cm) and the subsequent chemical reactions may be instrumental in the local formation of complex hydrocarbons.
    Keywords: LUNAR AND PLANETARY EXPLORATION
    Type: Icarus; 39; Sept
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  • 96
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    Dynamic satellite geodesy (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper describes operation of the GEOS-3 and Lageos spacecraft launched by NASA as part of the Earth and Ocean Dynamic Program. The investigations conducted by using GEOS-3 include the determination of tracking station coordinates, polar motion, and the use of altimetry in orbit determination. Lageos was designed as a precision target for making geodetic measurements with ground laser systems. Consideration is given to the progress made in the investigation and determination of tidal parameters by means of satellite perturbation methods. Satellite geodetic methods based on the ability to determine precise satellite orbits and orbit determination are outlined. Emphasis is placed on the future studies employing Spaceborne Laser and Global Positioning System concepts.
    Keywords: GEOPHYSICS
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  • 97
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    Earth's magnetosphere - Global problems in magnetospheric plasma physics (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Magnetospheric physics is presently in a transition from the exploratory stage to one in which satellite missions and ground-based observations are planned with the specific object of achieving a global understanding and self-consistent quantitative description of the cause-and-effect relationship among the principal dynamic processes involved. Measurements turn to lower and lower energies and to higher ion mass species, in order to encompass the entire particle population, and to a broader range of the frequency spectrum of magnetic and electric field variations. In the present paper, the current status of our knowledge on magnetospheric plasma physics is reviewed, with particular reference of such fundamental advances as the discovery of layers of streaming plasma in the magnetosphere beneath its boundary surface, the identification of the terrestrial magnetosphere as a celestial source of kilometric radiation and relativistic particles, the identification of parallel electric field regions within the magnetosphere and their role in auroral particle acceleration, and the discovery of large fluxes of energetic heavy ions trapped in the magnetosphere.
    Keywords: GEOPHYSICS
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  • 98
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    Satellite studies of the stratospheric aerosol (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The potential climatological and environmental importance of the stratospheric aerosol layer has prompted interest in measuring the properties of this aerosol. This paper reports on two recently deployed NASA satellite systems (SAM II and SAGE) that are monitoring the stratospheric aerosol. The satellite orbits obtain nearly global coverage. The instruments mounted in the spacecraft are sun photometers that measure solar intensity at specific wavelengths as it is moderated by atmospheric particulates and gases during each sunrise and sunset encountered by the satellites. Latitudinal, longitudinal, and temporal variations in the aerosol layer are evaluated. The satellite systems are being validated by a series of ground truth experiments using airborne and ground lidar, balloon-borne dustsondes, aircraft-mounted impactors, and other correlative sensors. The SAM II and SAGE satellite systems, instrument characteristics, and mode of operation are described; the methodology of the experiments is outlined; and the ground truth experiments are discussed. Preliminary results from these measurements are presented.
    Keywords: GEOPHYSICS
    Type: American Meteorological Society; vol. 60
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  • 99
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    Internal magnetospheric plasma flow (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Experimental evidence indicates that there exist at least two separate circulation patterns within the magnetosphere which allow cold heavy plasmaspheric ions, which drift toward the dayside magnetopause, to be transported to the plasma sheet for acceleration and reinjection into the inner magnetosphere. The first of these results in the ions being transported over the polar regions in the plasma mantle. The mantle ultimately joins the plasma sheet at great distance in the tail via the lobe electric field. The second circulation pattern is embodied in the low latitude boundary layer. Recent data show that the extension of the low latitude boundary layer in the tail at 60 Earth radii turns inward to directly feed the plasma sheet. A means of estimating the fractional role played by each is to compare the electric potential drop across the low latitude boundary layer with the total cross tail convection electric potential. This was done for a set of tail crossings using ALSEP/SIDE data. The result is that the boundary layer contains about 20% of the potential drop across the tail.
    Keywords: GEOPHYSICS
    Type: ESA Magnetospheric Boundary Layers; p 351-355
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  • 100
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    Martian meteorology (1979)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Viking mission results concerning the structure and dynamics of the Martian atmosphere are reviewed. The large-scale variability of pressure, temperature, and zonally averaged wind at the Lander sites is described, and small-scale phenomena involving the boundary layer and internal gravity waves are discussed. Observational evidence for the existence of transient planetary-scale waves, forced quasi-stationary waves, and thermal tides on Mars is examined. Atmospheric dynamics and properties of dust storms are considered, with emphasis on dust properties and distribution, the time evolution of planetwide dust storms, and dust-storm genesis and decay. Attention is also given to the nature of past Martian climates, the sizes and composition of volatile reservoirs, and volatile escape from the atmosphere.
    Keywords: LUNAR AND PLANETARY EXPLORATION
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