Cartwheel satellite synchronization system Patent
Spin phase synchronization of cartwheel satellite in polar orbit
Gatlin, J. A.↗
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Electromagnetic measurement of lunar subsurface water
Lunar subsurface water detection from satellite in polar orbit around moon by electromagnetic measurement
Jiracek, G. R.↗
Experimental evidence in support of Joule heating associated with geomagnetic activity
High resolution accelerometer measurements in the altitude region 140 to 300 km from a satellite in a near-polar orbit during a period of extremely high geomagnetic activity indicate that Joule heating is the primary source of energy for atmospheric heating associated with geomagnetic activity. This conclusion is supported by the following observational evidence: (1) There is an atmospheric response in the auroral zone which is nearly simulataneous with the onset of geomagnetic activity, with no significant response in the equatorial region until several hours later; (2) The maximum heating occurs at geographic locations near the maximum current of the auroral electrojet; and (3) There is evidence of atmospheric waves originating near the auroral zone at altitudes where Joule heating would be expected to occur. An analysis of atmospheric response time to this heat shows time delays are apparently independent of altitude but are strongly dependent upon geomagnetic latitude.
Devries, L. L.↗
Local-time survey of plasma at low altitudes over the auroral zones
A local-time survey of the low energy proton and electron intensities precipitated into the earth's atmosphere during periods of magnetic quiescence was constructed. A typical, individual satellite crossing of this region in each of eight local-time sectors was selected from a library of similar observations with the polar-orbiting satellite Injun 5. The trapping boundary for more energetic electron intensities, E 45 keV, is a natural coordinate for delineating the boundary between the two major types of lower energy, 50 or = E or = 15,000 eV. The main contributors to electron energy influx are inverted V precipitation poleward of the trapping boundary and the plasma sheet intensities equatorward. These are interpreted in terms of a magnetospheric model.
Frank, L. A.↗
HEOS-A2: Press kit
The characteristics of the HEOS-A2 satellite and its assigned mission are discussed. The spacecraft carries seven experiments to investigate the strength and direction of the magnetic fields encountered, the energy distribution of protons and electrons, the nature of the solar winds, detection of micrometeorites, and low frequency solar observations. The highly elliptical polar orbit required for this mission will have an apogee of 38 earth radii. The lifetime of the satellite is expected to be one year minimum.
Allaway, H. G.↗
An atlas of low latitude 6300A (01) night airglow from OGO-4 observations
The atomic oxygen emission line at 6300 A, measured in the nadir direction by a photometer on the polar orbiting satellite OGO-4, was plotted between 40 deg N and 40 deg S latitude on a series of maps for the moon-free periods between 30 August 1967 and 10 January 1968 The longitudinal and local time variations which occur during the northern fall-winter season are indicated. The northern tropical arc is more widespread while the southern arc is not present at all longitudes. The conditions under which the observations were made are described, and four airglow maps were selected to show the local time variations.
Reed, E. I.↗
High energy electron spikes at high latitudes
Over 750 spikes of precipitating electrons with E or = 425 KeV were observed aboard the low altitude polar orbiter OGO-D between 30 July 1967 and 31 December 1967. The spikes may be divided into three distinct populations, depending on whether they occur at latitudes below, at, or above the local limit of trapping.
Brown, J. W.↗
Magnetic control of the high latitude thermosphere
Observations made by the neutral mass spectrometer on board the polar orbiting OGO-6 satellite are given. Measurements were taken of the composition, density, and cyclic variations of gases in the high altitude thermosphere. Data were taken during the quiet magnetic period of August and early September 1969.
Hedin, A. E.↗
The magnetospheric plasma tail
The structural nature of the earth's plasmasphere at onset and immediately following an intense magnetic storm is examined. Thermal proton density measurements by the RF ion mass spectrometer on the low altitude polar orbiting satellite OGO-4 were compared on five consecutive nightside passes during the early recovery stage of an intense storm occuring in September 1967. Observational results revealed (1) characteristic termination of the dense plasmapause, (2) secondary enhancement of the ion density poleward of the first abrupt plasmapause, and (3) an elongated plasma tail during the recovery phase of the storm.
Grebowsky, J. M.↗
Observations of low-energy /0.3- to 1.8-MeV/ differential spectrums of trapped protons.
Measurements of differential energy spectrums of trapped protons obtained from several passes during the period January to November 1969 using the polar orbiting, low-altitude Injun 5 satellite equipped with a special solid-state detector proton-electron telescope are presented. Results reveal the existence of a quasi-persistent peak in the differential energy spectrum in the McIlwain shell parameter (L) range 2 to 2.6 and in the energy range of approximately 0.32 to 0.72 MeV. The fact that the shape of the spectrum is stable for several days or can change with time scales as small as 4 hours suggests an impulsive acceleration mechanism deep in the radiation belts. Other features of the spectrum show that if the spectrum is represented by an exponential form in energy, the dependence of the spectral parameter is in general agreement with diffusion theory over the L range of approximately 2 to 4.
Venkatesan, D.↗
Radiometer for remote sounding of the upper atmosphere.
The pressure-modulated carbon dioxide radiometer is a new kind of instrument capable of making temperature soundings in the 40-80-km region of the earth's atmosphere. It is intended to be mounted on a polar-orbiting satellite, where it will give global coverage of the upper atmosphere in a region that is not well understood at present but that is, as rocket soundings show, clearly the seat of many interesting and vigorous phenomena. The new technique employs a cell containing carbon dioxide as a filter. The pressure and hence transmission of this cell is periodically modulated, resulting in the selection of thermal radiation from the strong lines in the spectrum of atmospheric carbon dioxide. This radiation originates at levels in the atmosphere where the pressure is low. The energy grasp of the device is large enough to give high sensitivity.
Taylor, F. W.↗
Imp 5 magnetic-field measurements in the high-latitude outer magnetosphere near the noon meridian.
Results of Imp 5 magnetic-field measurements at geomagnetic latitudes up to 75 deg and at distances beyond six earth radii, revealing the permanent existence of a broad depressed field region centered on the polar or dayside cusp. Field strengths at seven earth radii on cusp field lines that connect to the earth are typically only 50 to 70% of that of an undistorted dipole field. The transition region between the magnetosheath and the point where the fields are clearly of dipolar origin is characterized by large-amplitude fluctuations and the lack of a clear magnetopause boundary. Magnetic-field perturbations are observed in the cusp region with magnitudes up to 45 gamma and in directions that are approximately perpendicular to the average field. These perturbations are suggestive of field-aligned currents, and their magnitudes are consistent with the low-altitude measurements obtained on polar-orbiting spacecraft.
Fairfield, D. H.↗
Global oceanic microwave anemometry - A planned space verification experiment.
Recent observations of the wind sensitivity of oceanic backscatter and temperature measurements are shown to have made it possible to design an experiment for verifying the potential use of an operational global satellite anemometer. The experiment is to be conducted with the Skylab in 1973, and its success may lead to the design and flight of an operational microwave scatterometer-radiometer instrument on a small satellite flying in a polar orbit sometime in the late 1970's.
Moore, R. K.↗
High-energy electron spikes at high latitudes.
Observation of over 750 spikes of precipitating electrons with E greater than or equal to 425 keV aboard the low-altitude polar orbiter Ogo 4 between July 30 and Dec. 31, 1967. The spikes may be divided into three distinct populations, depending on whether they occur at latitudes below, at, or above the local limit of trapping. These spikes are designated type 1, 2, and 3, respectively. Type 3 spikes occur in a narrow latitude band about 3 deg wide, centered at invariant latitude Lambda approximately equal to 78 deg at 1000 MLT (magnetic local time) and 68 deg at 2000 MLT. Type 3 spikes appear to be associated with spikes observed near the magnetopause and the neutral sheet. Type 2 spikes also occur in a latitude band about 3 deg wide, centered at about 71 deg at 1000 MLT and 67 deg at 2200 MLG. Type 2 spikes appear to be related to island fluxes in the neutral sheet, although they occur on closed field lines and may persist for many hours. Type 1 spikes occur in a wider band of latitudes, from about 62 deg to 68 deg near midnight and 66 deg to 68 deg near noon. Although they are observed on closed field lines, type 1 spikes do not persist for periods longer than about 1 hour, and it is concluded that they are produced by strong pitch-angle scattering from the stably trapped population.
Brown, J. W.↗
Local-time survey of plasma at low altitudes over the auroral zones.
Local-time survey of the low-energy proton and electron intensities precipitated into the earth's atmosphere over the auroral zones during periods of magnetic quiescence. This survey was constructed by selecting a typical individual satellite crossing of this region in each of eight local-time sectors from a large library of similar observations with the polar-orbiting satellite Injun 5. The trapping boundary for more-energetic electron intensities, E greater than 45 keV, was found to be a 'natural coordinate' for delineating the boundary between the two major types of lower-energy, 50 less than or equal to E less than or equal to 15,000 eV, electron precipitation commonly observed over the auroral zones at low altitudes. Poleward of this trapping boundary inverted 'V' electron precipitation bands are observed in all local-time sectors. These inverted 'V' electron bands in the evening and midnight sectors are typically more energetic and have greater latitudinal widths than their counterparts in the noon and morning sectors. In general, the main contributors to the electron energy influx into the earth's atmosphere over the auroral zones are the electron inverted 'V' precipitation poleward of the trapping boundary in late evening, the plasma-sheet electron intensities equatorward of this boundary in early morning, and both of these precipitation events near local midnight.
Frank, L. A.↗
The light ion trough, the main trough, and the plasmapause
Extensive observations of mid-latitude depletions in electron and total ion density by both direct and indirect techniques, have prompted numerous studies of the possible association between these troughs, observed in the F-region, the topside ionosphere, and the plasmapause. One basic problem arises, in that while the plasmapause was detected as a global phenomenon both by VLF and ion composition measurements, the electron and ion density troughs were identified primarily as nightside features. This problem, as well as the difficulty in explaining various inconsistencies in relating the position of the plasmapause and the ionization trough, is explained by a close examination of the ion composition. In particular, ion composition results from the polar orbiting OGO satellites identify the persistence of a pronounced light ion trough in H(+) and He(+) identified by order of magnitude decreases in the light ion concentrations.
Taylor, H. A., Jr.↗
The world surveyed in eighteen days
There are no author-identified significant results in this report. Earth Resources Technology Satellite 1 was launched on July 23, 1972, on a polar orbit at an altitude of approximately 900 kilometers. The satellite circles the earth fourteen times a day, and its multispectral scanners produce complete coverage of the world every 18 days. The scanning system of the satellite is designed to provide simultaneous images if the earth's surface, each in a different spectral band-green, orange/red, red, and infrared. This data is telemetered to stations on earth where it is processed from its digital form into corrected photographic images. A single photographic exposure covers an area of 185 square kilometers. Results of ERTS-1 have far exceeded all expectations and confirm the belief that the imagery obtained will be of wide-ranging value in the study and mapping of the earth's surface. The knowledge and experience gained from the ERTS-1 data will be applied to a further study based on the much more ambitious Skylab. The improvement in the material recovered from Skylab should mark a leap forward in technical quality and in the corresponding/potential of the imagery.
Mott, P. G.↗
Temporal variations in the dawn and dusk midlatitude trough position-modeled and measured (Ariel 3)
The temporal development of the latitudinal position of the 600 km midlatitude electron density trough at dawn and dusk during the period 25-27 May 1967, which encompassed a large magnetic storm, was measured by the RF capacitive probe on the polar orbiting Ariel 3 satellite. The substorm-related changes in the L coordinate of the trough minimum and the point of most rapid change of density gradient on the low latitude side of the trough are similar. Oscillations of the trough position at dusk are in phase with substorm activity whereas movement of the trough at dawn is only apparent with the onset of the large storm. Near dusk there is evidence of structure in the form of a tail-like extension of the plasmasphere at the peak of the storm. Detailed model calculations assuming a spatially invariant equatorial convection E field which varies in step with K sub p index reproduces much of the observed behavior, particularly at dusk, and shows that more than one plasmapause-type transition may be identifiable in the trough region.
Grebowsky, J. M.↗