Download or read book Lower thermosphere Neutral Density Profiles Derived from Satellite Accelerometer Data written by F. A. Marcos and published by . This book was released on 1976 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cannon Ball II and SPADES satellites carried triaxial accelerometer systems for accurate measurement of neutral atmospheric density. Cannon Ball II was launched 6 August 1971 into a polar elliptic orbit in which the initial perigee was at the extremely low altitude of 132 km. SPADES was launched 11 July 1968 into a polar elliptic orbit in which the initial perigee was at 155 km. The data, analyzed to deduce an average density profile for each satellite for summer conditions in the northern hemisphere, are for the altitude region 135 to 250 km, where measurements have heretofore been extremely sparse. Comparisons were made with recent models and experimental data. These results are intended to be supplemented by those of lower-thermosphere studies now being carried out on accelerometer data from the Atmosphere Explorer satellites and a low-altitude Air Force satellite. Comprehensive analyses of accelerometer data low-altitude satellites will allow accurate modeling of the lower thermosphere. These models are required for improving calculation of the trajectories of Air Force systems vehicles and other spacecraft.
Download or read book Lower thermosphere Neutral Density Profiles Derived from Satellite Accelerometer Data written by F. A. Marcos and published by . This book was released on 1976 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cannon Ball II and SPADES satellites carried triaxial accelerometer systems for accurate measurement of neutral atmospheric density. Cannon Ball II was launched 6 August 1971 into a polar elliptic orbit in which the initial perigee was at the extremely low altitude of 132 km. SPADES was launched 11 July 1968 into a polar elliptic orbit in which the initial perigee was at 155 km. The data, analyzed to deduce an average density profile for each satellite for summer conditions in the northern hemisphere, are for the altitude region 135 to 250 km, where measurements have heretofore been extremely sparse. Comparisons were made with recent models and experimental data. These results are intended to be supplemented by those of lower-thermosphere studies now being carried out on accelerometer data from the Atmosphere Explorer satellites and a low-altitude Air Force satellite. Comprehensive analyses of accelerometer data low-altitude satellites will allow accurate modeling of the lower thermosphere. These models are required for improving calculation of the trajectories of Air Force systems vehicles and other spacecraft.
Download or read book Lower Thermosphere Density Variations in the Southern Hemisphere written by F. A. Marcos and published by . This book was released on 1972 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Profiles of the neutral atmospheric density have been obtained at high and middle latitudes in the southern hemisphere from OV1-15 (SPACES) satellite accelerometer measurements. The data were obtained during a geomagnetically quiet period near the equinox, 24-28 September 1968, when the satellite was in a nearly down-dusk orbit. Perigee moved from 50 degrees S to 65 degrees S during this period. Measurements were made in the altitude range 170-250 km. Density values at dusk at high latitudes (before perigee) are less than those at midlatitudes (after perigee). The average difference between the high latitude and midlatitude data is 15 percent. A longitudinal variation is superimposed on the latitudinal gradients. Enhanced densities at high southern latitudes are found at longitudes near the south geomagnetic pole. (Author).
Download or read book Dynamics and Structure of the Quiet Thermosphere written by K. S. W. Champion and published by . This book was released on 1974 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The COSPAR International Reference Atmospheres (CIRA) 1972 provides both a Mean International Reference Atmosphere of the thermosphere and a parametric set of models for the region. The models are based on knowledge of the thermosphere as of mid 1971. The differences in the diurnal variations of atmospheric density scale height obtained from satellite drag studies and temperatures obtained from incoherent radar scatter observations are probably due to different diurnal variations of density and temperature and not due to systematic discrepancies in the measurements. The answer to this question should be provided by data obtained from recently launched satellites ESRO IV, AEROS, and AE-C. The second major area of interest involves the absolute number densities and variations with time of day, latitude, and season of the major and minor constituents of the thermosphere. Recent data obtained with mass spectrometers and optical instruments are reviewed in addition to the results of theoretical composition calculations, which include turbulence and other transport effects.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 1460 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Instrumentation Papers written by and published by . This book was released on 1978 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Satellite Density Measurements with the Rotatable Calibration Accelerometer ROCA written by Frank A. Marcos and published by . This book was released on 1979 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Satellite accelerometer measurements of atmospheric density have provided significant improvement in our understanding of the structure and dynamics of the lower thermosphere. Derivation of accurate data with this technique requires removal of instrument bias from the total sensor output. The ROCA (Rotatable Calibration Accelerometer) experiment was flown to provide and orbital calibration capability on the three-axis stabilized S3-4 satellite. The ROCA sensitive axis could be operated in either of two orientations selectable by ground command. For density measurement (normal operating mode) the sensitive axis was aligned with the satellite velocity vector. For direct measurement of bias, the sensitive axis was aligned perpendicular to the velocity vector. Utilization of the inflight calibration technique showed a dependence of the bias upon the instrument operating temperature. Removal of the bias-temperature component from the total acceleration signal obtained in the normal operating mode permits derivation of accurate density data. Measurements of atmospheric density were obtained during approximately 600 orbits over a five month period. The resulting ROCA data will be utilized for improved satellite ephemeris computations and for detailed studies of the lower thermosphere, particularly those related to energy inputs at high latitudes. (Author).
Download or read book A Global Thermospheric Density Model Based on Satellite Accelerometer Data written by Frank A. Marcos and published by . This book was released on 1982 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Ionosphere Thermosphere written by J. D. Huba and published by John Wiley & Sons. This book was released on 2014-03-17 with total page 735 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 201. Modeling the Ionosphere-Thermosphere System brings together for the first time a detailed description of the physics of the IT system in conjunction with numerical techniques to solve the complex system of equations that describe the system, as well as issues of current interest. Volume highlights include discussions of: Physics of the ionosphere and thermosphere IT system, and the numerical methods to solve the basic equations of the IT system The physics and numerical methods to determine the global electrodynamics of the IT system The response of the IT system to forcings from below (i.e., the lower atmosphere) and from above (i.e., the magnetosphere) The physics and numerical methods to model ionospheric irregularities Data assimilation techniques, comparison of model results to data, climate variability studies, and applications to space weather Providing a clear description of the physics of this system in several tutorial-like articles, Modeling the Ionosphere-Thermosphere System is of value to the upper atmosphere science community in general. Chapters describing details of the numerical methods used to solve the equations that describe the IT system make the volume useful to both active researchers in the field and students.
Download or read book R D Abstracts written by Technology Reports Centre (Great Britain) and published by . This book was released on 1976 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Atmospheric Density Variations in the Southern Hemisphere at Low Satellite Altitudes written by F. A. Marcos and published by . This book was released on 1975 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate density measurements are required to develop predictive atmospheric models. Of particular concern is the altitude region below 250 km. Few measurements are presently available in this region and data are urgently required by the Air Force for accurate ephemeris, trajectory, and reentry predictions. Profiles of neutral atmospheric density obtained at low satellite altitudes in the southern hemisphere during geomagnetically quiet conditions are described in this report.
Download or read book Meteorological and Geoastrophysical Abstracts written by and published by . This book was released on 1996 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fundamentals of Space Systems written by Vincent L. Pisacane and published by Johns Hopkins University Appli. This book was released on 2005 with total page 872 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fundamentals of Space Systems was developed to satisfy two objectives: the first is to provide a text suitable for use in an advanced undergraduate or beginning graduate course in both space systems engineering and space system design. The second is to be a primer and reference book for space professionals wishing to broaden their capabilities to develop, manage the development, or operate space systems. The authors of the individual chapters are practicing engineers that have had extensive experience in developing sophisticated experimental and operational spacecraft systems in addition to having experience teaching the subject material. The text presents the fundamentals of all the subsystems of a spacecraft missions and includes illustrative examples drawn from actual experience to enhance the learning experience. It includes a chapter on each of the relevant major disciplines and subsystems including space systems engineering, space environment, astrodynamics, propulsion and flight mechanics, attitude determination and control, power systems, thermal control, configuration management and structures, communications, command and telemetry, data processing, embedded flight software, survuvability and reliability, integration and test, mission operations, and the initial conceptual design of a typical small spacecraft mission.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1977 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Bibliography with Abstracts of AFCRL Publications from 1 October to 31 December 1972 written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1973 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements written by and published by . This book was released on 1974 with total page 876 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Report on Research at AFCRL written by Air Force Cambridge Research Laboratories (U.S.) and published by . This book was released on 1976 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
