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NASA NTRS1984

Connection Between the Magnetosphere and Ionosphere

Two decades of space research have produced ample evidence that particles and fields originating in the active Sun can gain entry into the terrestrial magnetosphere and deposit their energy in the ionosphere and atmosphere. The final link in this solar-terrestrial chain is generically referred to as magnetosphere-ionosphere coupling (MIC). Because of the far-reaching implications of recent discoveries in MIC and because a coherent assessment of them has yet to be made, the principal task is to critically assess these new observations and the new perspectives that they may engender. The MIC topics of interest are roughly grouped according to the scale lengths of the phenomena being treated. This particular choice of groupings is mainly for convenience, with perhaps some suggestion as to the direction of energy cascade from the largest scales down to the smaller scale.

Source record↗
NASA NTRS1984

In Situ Data

In-situ planetary data include all measurements made by a wide variety of instruments whose sensors are exposed directly to the planetry environment. Typical measurements include those of magnetic fields, energetic particle densities and energy distributions, plasma wave characteristics, ionospheric and neutral gas densities, temperatures, composition and motions. A large body of scientists in the United States, and the world, are involved in research using in-situ data. Many of these scientists are associated with Mission investigations groups which provide specific types of in-situ data. These groups, in the course of data analysis, use data provided by similar groups. The interdisciplinary nature of these investigations fosters exchange and reliance upon one another for data is heavy. To a lesser extent, correlative data sets are obtained from the National Space Science Data Center (NSSDC). However, the data entries often have limited temporal and spatial resolution, are of uncertain quality, and are usually available only for measurements that are several years old.

Source record↗
NASA NTRS1984

Concepts used in the preparation of the document - Space and planetary environment criteria guidelines for use in space vehicle development 1982 revision

The NASA/Marshall Space Flight Center has developed a series of documents concerning space and planetary environments for use in the formulation of aerospace vehicle and spacecraft design criteria. For the earth above 90km altitude, and for the moon, planets, and other bodies in the Solar System; information is provided in disciplinary area of importance to the spacecraft designer such as planetary geology and morphology, atmospheric and ionospheric structures, radiation, particles, geomagnetic fields, astrodynamic constants, and meteoroids. This paper presents the philosophy used in the preparation of the current (1982) version of the document. Specific topics will be discussed in relation to their significance for aerospace vehicle and spacecraft development and mission analysis.

Davis, M. H.↗
NASA NTRS1984

ISEE-3 wave measurements in the distant geomagnetic tail and boundary layer

The ISEE-3 excursion into the distant tail region reveals a complex structure with several wave, particle and field characteristics that differ significantly from those measured closer to earth. The most striking results are found within the distant boundary layer where intense electrostatic turbulence levels are detected in association with bidirectional electron distributions. The wave amplitudes appear to increase with increasing downstream distance and the polarizations are those expected for ion acoustic oscillations. Near the boundary of the distant plasmas sheet the turbulence spectra are essentially identical to those measured much closer to earth on IMP-8. It is also found that in the distant tail the continuum radiation spectrum has a low frequency cutoff that is much higher than the minimum value for the local plasma frequency.

Scarf, F. L.↗
NASA NTRS1984

The path-length distribution for galactic cosmic-ray propagation - An energy-dependent depletion of short path lengths

It is shown that at low energies, the depletion of short path lengths in the interstellar cosmic-ray path-length distribution is a function of energy, decreasing in magnitude with increasing energy. The analysis leading to this conclusion is based on the comparison of compiled data for the B/C and sub-Fe/Fe ratios at 0.08-50 GeV per nucleon, with the results of detailed galactic propagation and solar modulation calculations, which include experimental values for the important nuclear cross sections. This energy dependence of the depletion resolves some of the conflicts between previous reports on the question of short path lengths and may be explained by models including a matter distribution around discrete sources or, possibly, by models invoking waves generated by particle-magnetic field interactions in the Galaxy.

Garcia-Munoz, M.↗
NASA NTRS1984

Starprobe - To confront the sun

Starprobe is an advanced-technology mission that is being planned for the purpose of making a very close approach to the sun; perhaps as near as four solar radii. The scientific experiments will accurately measure the solar quadrupole moment, conduct relativity experiments, measure the fields and particles environment, and image solar features at high resolution. An effective heat shield is required, and the communications system must be capable of returning data while the spacecraft is immersed in the noisy solar environment. The spacecraft's earth-inherited angular momentum will be removed for the drop into the sun by means of a close flyby of Jupiter.

Mclaughlin, W. I.↗
NASA NTRS1986

Improved Electronic Control for Electrostatic Precipitators

Electrostatic precipitators remove particulate matter from smoke created by burning refuse. Smoke exposed to electrostatic field, and particles become electrically charged and migrate to electrically charged collecting surfaces. New microprocessor-based electronic control maintains precipitator power at maximum particulate-collection level. Control automatically senses changes in smoke composition due to variations in fuel or combustion and adjusts precipitator voltage and current accordingly. Also, sensitive yet stable fault detection provided.

Johnston, D. F.↗
NASA NTRS1984

Magnetohydrodynamic and gasdynamic theories for planetary bow waves

The observed properties of bow waves and the associated plasma flows are outlined, along with those features identified that can be described by a continuum magnetohydrodynamic flow theory as opposed to a more detailed multicomponent particle and field plasma theory. The primary objectives are to provide an account of the fundamental concepts and current status of the magnetohydrodynamic and gas dynamic theories for solar wind flow past planetary bodies. This includes a critical examination of: (1) the fundamental assumptions of the theories; (2) the various simplifying approximations introduced to obtain tractable mathematical problems; (3) the limitations they impose on the results; and (4) the relationship between the results of the simpler gas dynamic-frozen field theory and the more accurate but less completely worked out magnetohydrodynamic theory. Representative results of the various theories are presented and compared. A number of deficiencies, ambiguities, and suggestions for improvements are discussed, and several significant extensions of the theory required to provide comparable results for all planets, their satellites, and comets are noted.

Spreiter, J. R.↗
NASA NTRS1983

Galilean satellite remote sensing by the Galileo Jupiter Orbiter

The derivation of a mission design strategy for the Galileo Jupiter Orbiter which best satisfies the requirements for remote sensing of the surfaces of the Galilean satellites during a 20-month orbital tour of the Jovian system is described. The celestial mechanics of a spacecraft orbiting about Jupiter and interacting with the Galilean satellites is discussed. A satellite tour strategy designed to optimize the accomplishment of remote sensing, field and particle science, and radio science objectives is developed. Finally, an assessment is made of how well these objectives can be met given the spacecraft, the capabilities of the scientific instruments, and the structure of the satellite tour.

Yeates, C. M.↗
NASA NTRS1983

Weighted least squares formulas for multiple Doppler radar analysis

An algorithm is developed for the analysis of multiple Doppler radar data in meteorological applications. The algorithm is based on the least squares linear solutions for the variable parameters of a local particle velocity field. The computational sequence for the algorithm is described, and some factors influencing the covariance of Doppler measurement errors are discussed.

Wilson, F. W., Jr.↗
NASA NTRS1985

Thermospheric and ionospheric structure of the Southern Hemisphere polar cap on October 21, 1981, as determined from Dynamics Explorer 2 satellite data

For a number of years, satellites have been employed to measure auroral particles and fields within the high-latitude thermosphere. In the present paper, data from orbit 1174 of the Dynamics Explorer 2 satellite on October 21, 1981, are utilized to calculate the structure of the ionosphere and thermosphere below the satellite altitude down to about 80 km. Attention is given to details regarding the DE 2 measurements, a satellite track model, the calculated ionospheric structure, and the calculated neutral gas heating rates. The investigation demonstrates that the technique of deriving characteristics of the ionosphere and atmosphere below a satellite track promises to be very fruitful for defining the characteristics of the lower thermosphere for use in large numerical models of the thermosphere and ionosphere.

Emery, B. A.↗
NASA NTRS1985

Report on active and planned spacecraft and experiments

This report provides the professional community with information on current and planned spacecraft activity (including both free-flying spacecraft and Shuttle-attached payloads) for a broad range of scientific disciplines. By providing a brief description of each spacecraft and experiment as well as its current status, it is hoped that this document will be useful to many people interested in the scientific, applied, and operational uses of the data collected. Furthermore, for those investigators who are planning or coordinating future observational programs employing a number of different techniques such as rockets, balloons, aircraft, ships, and buoys, this document can provide some insight into the contributions that may be provided by orbiting instruments. The document includes information concerning active and planned spacecraft and experiments. The information covers a wide range of scientific disciplines: astronomy, earth sciences, meteorology, planetary sciences, aeronomy, particles and fields, solar physics, life sciences, and material sciences. These spacecraft projects represent the efforts and funding of individual countries, as well as cooperative arrangements among different countries.

Schofield, N. J., Jr.↗
NASA NTRS1985

The GOES-G and -H spacecraft design

The design of the Geostationary Operational Environmental Satellites (GOES) uses newer technology and has expanded capability relative to the predecessor GOES series of satellites. The satellite directly transmits day and night observations of hemispheric-scale weather, hurricanes, and other more localized severe storms and relays processed high-resolution observation data along with weather facsimile (WEFAX) data. Weather observations are generated in the visible and infrared spin scan radiometer (VISSR) atmospheric sounder (VAS). The VAS performs visible and infrared imaging as well as multispectral imaging (MSI) and temperature sounding of the atmosphere. The satellite provides direct interrogation and simultaneous relay transmission between the command data acquisition station (CDAS) and the multiple, widely dispersed data collection platforms (DCP). The satellites also monitor the condition of the earth's magnetic field, energetic particle flux, and X-ray emissions from the sun. The satellite performs all communications functions by means of a multifunction communications system that operates on S-band and uhf frequencies at rates varying from 100 bit/s to 28 megabit/s. An experimental capability for the detection of the emergency locator transmitter beacons is included in the GOES-GH design as a part of the international satellite-aided search and rescue system.

Fermelia, L. R.↗
NASA NTRS1986

On plasma disturbances caused by the motion of the Space Shuttle and small satellites - A comparison of in situ observations

Recent results regarding the interactions between a body and its environmental space plasma, made by charged particle probes mounted in the bay of the Space Shuttle Orbiter Columbia (STS 3 mission), are compared with earlier results, obtained from small ionospheric satellites, in an attempt to widen our scope of knowledge and understanding regarding such interactions. The objective is to work toward a unified model of body-space plasma interactions in the solar system covering a variety of plasma and body conditions. The comparisons focus mainly on (1) the (wake/ram) current ratio; (2) the generation of charged particle density fluctuations (indicative of plasma turbulence) around the body; and (3) the increase in electron temperature ahead and in the wake of the satellite. The main results of the comparison are that (1) the (wake/ram) current ratio (or current depletion in the wake) for the Orbiter is 1 to 2 orders of magnitude larger than the ratio for small ionospheric satellites; and (2) fluctuations in density (or turbulence) are observed for both 'large body' (Shuttle Orbiter) and 'smaller body' (standard ionospheric satellites). However, the cause of the turbulence may not be the same for both cases; (3) the results for the electronic temperature enhancement due to the Shuttle Orbiter are in contrast with measurements from smaller ionospheric satellites. A path to follow in future Shuttle experiments is suggested and caution that care be taken in interpreting local particle and field measurements.

Samir, U.↗
NASA NTRS1985

Plasmas in the earth's magnetotail

An overview of the general charcteristics of plasmas within the earth's magnetotail and its environs is presented. Present knowledge of the plasma within these regions as gained via in situ measurements provides the general theme, although observations of magnetic fields, energetic particles and plasma waves are included in the discussion. Primary plasma regimes in the magnetotail are the plasma sheet, its boundary layer, the magnetotail lobes, the boundary layer at the magnetopause and the distant magnetotail. Although great progress in the understanding of these regions is evident in the literature of the past several years, many of their features remain as exciting enigmas to be resolved by future observational and theoretical investigation.

Frank, L. A.↗
NASA NTRS1987

Essays in Space Science

The papers presented cover a broad segment of space research and are an acknowledgement of the personal involvement of Frank McDonald in many of these efforts. The totality of the papers were chosen so as to sample the scientific areas influenced by him in a significant manner. Three broad areas are covered: particles and fields of the solar system; cosmic ray astrophysics; and gamma ray, X-ray, and infrared astronomics.

Ramaty, Reuven↗
NASA NTRS1986

The Venus ultraviolet aurora - Observations at 130.4 nm

Continuous and highly variable emissions at 130.4 nm are observed on the night-side of Venus by the Pioneer Venus Orbiter ultraviolet spectrometer. The emissions have a typical intensity of 10-20 R, occasionally exceed 100 R, and have a dawn-dusk symmetry in brightness during periods of unusual intensity. Possible energy source for this 'aurora' is the precipitation of suprathermal electrons. Field and particle observations suggest an additional source for the brightest emissions which is associated with solar flares and/or interplanetary shocks.

Phillips, J. L.↗
NASA NTRS1986

Ion energization in upwelling ion events

A source of H(+), He(+), O(+), and N(+) outflow from the ionosphere has been identified near the polar cusp/cleft using the Dynamics Explorer/retarding ion mass spectrometer data set. This ion outflow termed 'upwelling ions' is characterized by large outfluxes of H(+) and O(+) ions and high transverse ion temperatures. This paper reports on the associated particle and field characteristics of one such upwelling ion event on March 12, 1982. Field-aligned currents and strong E x B convection channels are associated with the event as well as strong broadband plasma wave emission. One or all of these sources may play an important role in the ion energization in this region.

Waite, J. H., Jr.↗