236
236
May 6, 2010
05/10
by
Jacchia, L. G
texts
eye 236
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No Abstract Available
Topics: ATMOSPHERIC DENSITY, SCALE HEIGHT
207
207
Jun 18, 2010
06/10
by
Vorobyev, G. G
texts
eye 207
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Tektite origin and Czechoslovakian field locations - solar activity and atmospheric density
Topics: ATMOSPHERIC DENSITY, CZECHOSLOVAKIA, POSITION (LOCATION), SOLAR ACTIVITY, TEKTITES, ATMOSPHERIC...
190
190
Jul 11, 2010
07/10
by
BASLER, A
texts
eye 190
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THE OBJECT OF THIS STUDY WAS TO DETERMINE HOW SMALL A DISPLACEMENT MAY BE PERCEIVED AS MOVEMENT. SUBJECTS OBSERVED MINUTE DISPLACEMENTS OF A LEVER, MOUNTED ON A METAL SHEET AND VISIBLE THROUGH A SLIT IN A COVERING SHEET. IT WAS FOUND THAT IN THE MACULA LUTEA A MOVEMENT THROUGH A VISUAL ANGLE OF 20 SEC IS PERCEIVED, EVEN THOUGH TWO POINTS LESS THAN 50 SEC APART ARE NOT DISTINGUISHED AS SEPARATE. SUBJECTS CONSIDERABLY OVERESTIMATED MINUTE MOVEMENTS, ESPECIALLY WHEN THE MOVING OBJECT WAS CLOSE TO...
Topics: SANDS, WIND VELOCITY, ATMOSPHERIC DENSITY, GRAINS, HUMIDITY
230
230
Jun 20, 2010
06/10
by
Lam, L. S.; Lundquist, C. A.; Mendes, G. M
texts
eye 230
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Satellite experiment design for atmospheric density and near-free molecule flow aerodynamics
Topics: AERODYNAMICS, SATELLITE DRAG, ATMOSPHERIC DENSITY, EXPERIMENT DESIGN, FREE MOLECULAR FLOW,...
644
644
Jul 6, 2010
07/10
by
ROTH, W
texts
eye 644
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comment 1
CRITICAL FLUTTER VELOCITY FOR A MEMBRANE IN A NONCONSERVATIVE SYSTEM IS CONSIDERED. IT IS SHOWN THAT THE DAMPING FORCES HAVE A DESTABILIZING EFFECT AND THAT A DISCONTINUITY APPEARS IN THE STABILITY CRITERION WHICH DEPENDS ON THE DAMPING COEFFICIENT AND IS CHARACTERISTIC OF NONCONSERVATIVE SYSTEMS. BY MEANS OF THIS THEORY, THE FLUTTER OF WEATHER VANES OR SAILS, AS WELL AS THE RELATED TRAVELING TRANSVERSE WAVES, CAN BE EXPLAINED.
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Topics: ATMOSPHERIC DENSITY, LUMINANCE, METEOROIDS, MATHEMATICAL MODELS, METEOR TRAILS, TURBULENCE,...
436
436
May 27, 2011
05/11
by
PANOV, V. V.; SOBOLEV, YU. S
texts
eye 436
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THE ULTIMATE SERVICEABILITY OF GAS TURBINE ENGINE LUBRICATING OILS IS ASSESSED ON THE BASIS OF RESULTS OF TESTS ON INDIVIDUAL FRICTIONAL ASSEMBLY INSTALLATIONS OF ENGINES AND ON FULL-SCALE ENGINES. IN CERTAIN CASES, OILS ARE TESTED UNDER IN-FLIGHT CONDITIONS.
Topics: COLLISIONS, METEORITES, METEOROIDS, MOLECULES, ATMOSPHERES, DECELERATION, ATMOSPHERIC DENSITY
269
269
Jul 11, 2010
07/10
by
Peng, Y. K. M.; Crawford, F. W
texts
eye 269
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The electrostatic resonance properties of an inhomogeneous plasma column are reported by application of the Rayleigh-Ritz method. A description of the rf equation of motion and pressure term that expresses the system of equations in Euler-Lagrange form is presented. The Rayleigh-Ritz procedure is applied to the corresponding Lagrangian to obtain approximate resonance frequencies and eigenfunctions. An appropriate set of trial coordinate functions is defined, which leads to frequency and...
Topics: EARTH ATMOSPHERE, LASERS, SOUNDING, AEROSOLS, ATMOSPHERIC DENSITY, BACKSCATTERING
The neutral upper atmospheric models for the Earth's thermosphere currently used in NASA-MSFC programs are the Jacchia 1970 (J70), 1971 (J71), and 1977 (J77). The Jacchia 1970 model (modified) is used in all MSFC orbital mechanics analyses. Since total density and its variations are the main environmental parameters of interest in orbital lifetime and attitude control studies, the total neutral density was selected for this analysis. This report presents the results of a parametric study of the...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC DENSITY, THERMOSPHERE, UPPER ATMOSPHERE,...
1,177
1.2K
May 27, 2011
05/11
by
Love, Eugene S.; Grigsby, Carl E.; Lee, Louise P.; Woodling, Mildred J
texts
eye 1,177
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Some experimental and theoretical studies have been made of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams with a view toward problems associated with propulsive jets and the investigation of these problems. For jets exhausting into still air, consideration is given to the effects of jet Mach number, nozzle divergence angle, and jet static pressure ratio upon jet structure, jet wavelength, and the shape and curvature of the jet...
Topics: SOLAR RADIATION, RADIATION PRESSURE, ARTIFICIAL SATELLITES, SATELLITE TRACKING, ORBITAL RENDEZVOUS,...
383
383
Jul 11, 2010
07/10
by
MASSON, A
texts
eye 383
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THE INSTALLATION FOR INVESTIGATIONS ON FULLSCALE OR LARGE-SCALE MODELS OF CONVENTIONAL AIRCRAFT OR CONVERTIPLANE PROPELLERS IN A LARGE SONIC WIND TUNNEL IS DESCRIBED. SOME EXAMPLES OF TESTS CARRIED OUT AND TYPICAL RESULTS OBTAINED ILLUSTRATE THE USE CAPABILITY OF THE EQUIPMENT, WHICH IS ALSO SUITABLE FOR HELICOPTER ROTOR TESTS.
Topics: AERODYNAMIC DRAG, ORBIT CALCULATION, SPACECRAFT CONTROL, TRAJECTORY ANALYSIS, ATMOSPHERIC DENSITY,...
448
448
May 6, 2010
05/10
by
Ratcliffe, James G
texts
eye 448
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This technical publication details part of an effort focused on the development of a standardized facesheet/core peel debonding test procedure. The purpose of the test is to characterize facesheet/core peel in sandwich structure, accomplished through the measurement of the critical strain energy release rate associated with the debonding process. Following an examination of previously developed tests and a recent evaluation of a selection of these methods, a single cantilever beam (SCB)...
Topics: MARS ATMOSPHERE, SENSITIVITY, ATMOSPHERIC MODELS, TOPOGRAPHY, MARS (PLANET), TEMPERATURE,...
Refinements in the accelerometer system used in the falling-sphere atmospheric density measuring system have been implemented. These include a redesigned Z-axis amplifier chain, range scale changes in the X and y axis amplifier outputs to provide overlap, and a new temperature monitor circuit. The squib initiation circuit and squib holder bushing has been redesigned for greater reliability. Calibration has been improved by the use of a specially-designed function generator. Five systems were...
Topics: DTIC Archive, Fryklund,Donald H, ACCUMETRICS CORP CAMBRIDGE MA, *ACCELEROMETERS, MODIFICATION,...
270
270
Jun 27, 2010
06/10
by
Spizzichino, A
texts
eye 270
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Meteor trails observations of wind component interactions in upper atmosphere
Topics: ATMOSPHERIC DENSITY, ATMOSPHERIC PHYSICS, CHARGE DISTRIBUTION, ELECTRON DENSITY (CONCENTRATION),...
172
172
Aug 1, 2010
08/10
by
Smart, Anthony E
texts
eye 172
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The Rolls-Royce Transit Anemometer was applied to several rigs in the Whittle Laboratory. These included a 14 inch calibration jet, to demonstrate the intrinsic accuracy of the machine, and a static turbine cascade in which midspan traverses were produced of the entire duct and a boundary layer. Both of these plots accorded well with previous data and were very much more easily obtained. Data from a rotating cascade was encouraging. First, some measurements were made upstream without time...
Topics: ATMOSPHERIC DENSITY, ATMOSPHERIC EFFECTS, LUNAR ATMOSPHERE, LUNAR EXPLORATION, ELECTRIC FIELDS,...
182
182
Jul 5, 2010
07/10
by
Broglio, L
texts
eye 182
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comment 0
No Abstract Available
Topics: ARTIFICIAL CLOUDS, IONOSPHERIC SOUNDING, ATMOSPHERIC DENSITY, ATMOSPHERIC TURBULENCE, SODIUM, WIND...
1,388
1.4K
Jun 21, 2010
06/10
by
Yakovlev, A. S
texts
eye 1,388
favorite 2
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History of USSR aviation industry, aircraft design, and air transportation
Topics: ARTIFICIAL SATELLITES, ATMOSPHERIC DENSITY, VISUAL OBSERVATION, GRAPHS (CHARTS), SYNCHRONISM,...
206
206
Jun 13, 2011
06/11
by
Robinson, J. H.; Watson, W. R
texts
eye 206
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The current fleet of large commercial aircraft has successfully achieved FAA noise certifications because of, in part, the successful application of uniform passive duct liner treatments to control engine system noise. One goal of NASA's engine system noise reduction program is to develop technologies to improve the sound absorbing properties of duct liner treatments so that they remain effective in modern turbo fan engines. One such technology being studied is checkerboard or periodic axially...
Topics: ATMOSPHERIC MODELS, MARS GLOBAL SURVEYOR, MARS ATMOSPHERE, THERMAL EMISSION, HEAT SHIELDING, MONTE...
200
200
Jul 10, 2010
07/10
by
JUUL, J
texts
eye 200
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RESULTS ACHIEVED WITH AN EXPERIMENTAL WINDMILL ARE ELABORATED ON: GREATEST EFFICIENCY OF THE MILL WAS OBTAINED AT A WINGTIP VELOCITY OF 38 M/X; EFFECTS CAUSED BY WIND PRESSURE SHOULD NOT EXCEED 800 KG/SQ CM IN ANY PART OF THE WING OR TOWER, AND EFFECTS CAUSED BY GRAVITY IN THE WINGS SHOULD NOT EXCEED 200-300 KG/SQ CM. EXPERIENCE HAS SHOWN THAT THE OPTIMAL HEIGHT OF THE SUPPORT TOWER SHOULD BE FROM 18-24 M. A HISTORY OF THE DUTCH WINDMILL'S USE AND ITS CONSTRUCTION, AND ALSO OF VARIOUS MODERN...
Topics: THERMODYNAMIC PROPERTIES, VENERA 4 SATELLITE, VENUS ATMOSPHERE, ATMOSPHERIC DENSITY, ATMOSPHERIC...
371
371
May 31, 2011
05/11
by
Zwally, H. J.; Harding, D., et al; Schutz, B.; Abdalati, W.; Abshire, J.; Bentley, C.; Brenner, A.; Bufton, J.; Dezio, J.; Hancock, D.
texts
eye 371
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The Ice, Cloud and Land Elevation Satellite (ICESat) mission will measure changes in elevation of the Greenland and Antarctic ice sheets as part of NASA's Earth Observing System (EOS) of satellites. Time-series of elevation changes will enable determination of the present-day mass balance of the ice sheets, study of associations between observed ice changes and polar climate, and estimation of the present and future contributions of the ice sheets to global sea level rise. Other scientific...
Topics: FLIGHT CHARACTERISTICS, PROPULSION SYSTEM CONFIGURATIONS, SPACECRAFT PROPULSION, MARS ATMOSPHERE,...
247
247
Jun 21, 2010
06/10
by
Bushnell, D. M
texts
eye 247
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comment 0
Leading-edge heat transfer effects of three types of interfering flow fields
Topics: AIRSPEED, AUTOROTATION, DIAGRAMS, HEIGHT, HELICOPTERS, ATMOSPHERIC DENSITY, NUMERICAL ANALYSIS,...
291
291
texts
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There are no author-identified significant results in this report.
Topics: MARS ATMOSPHERE, MARS SURFACE, MARS 3 SPACECRAFT, ATMOSPHERIC DENSITY, INFRARED RADIATION,...
A brief historical account of data and theory pertaining to the lunar atmosphere prior to the Apollo program is presented. It consists of a summary of the most important pre-Apollo research, rather than an exhaustive bibliographical study, and constitutes a supporting analytical study for the Apollo 17 UV Spectrometer Experiment.
Topics: NASA Technical Reports Server (NTRS), APOLLO 17 FLIGHT, LUNAR ATMOSPHERE, ULTRAVIOLET SPECTROSCOPY,...
Three tasks completed in this study are presented. (1) The climatologic model of scintillation index S4 map using the ROCSAT data during the moderate to high solar activity period is completed using the ROCSAT 32 Hz density fluctuation data collected at the 600 km altitude. The results are divided into two maps, one for strong scintillation (S4=0.3) and the other, weak scintillation (S40.3). (2) Study of coincident scintillation events between NCU-SCINDA data, COSMIC observations, and C/NOFS...
Topics: DTIC Archive, NATIONAL CENTRAL UNIV CHUNG-LI (TAIWAN) INST OF SPACE SCIENCE, *IONOSPHERIC...
A compact formalism is developed that provides expressions for satellite aerodynamic drag perturbations when an exponentially varying atmospheric density distribution is assumed. This formalism is well suited for efficient manipulation and computation using the electronic computer.
Topics: DTIC Archive, Parks,A D, NAVAL SURFACE WEAPONS CENTER DAHLGREN VA, *ARTIFICIAL SATELLITES,...
274
274
Jul 11, 2010
07/10
by
Mclaren, A. D
texts
eye 274
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comment 0
Sensitive tests for the detection of extracellular enzyme activity in Martian soil was investigated using simulated Martian soil. Enzyme action at solid-liquid water interfaces and at low humidity were studied, and a kinetic scheme was devised and tested based on the growth of microorganisms and the oxidation of ammonium nitrite.
Topics: ATMOSPHERIC DENSITY, WIND VELOCITY, ATMOSPHERIC PRESSURE, ATMOSPHERIC TEMPERATURE, VENUS...
A technique is presented for processing accelerometer data obtained during the AE missions in order to estimate the atmospheric density profile. A minimum variance, adaptive filter is utilized. The trajectory of the probe and probe parameters are in a consider mode where their estimates are unimproved but their associated uncertainties are permitted an impact on filter behavior. Simulations indicate that the technique is effective in estimating a density profile to within a few percentage...
Topics: NASA Technical Reports Server (NTRS), ACCELEROMETERS, ADAPTIVE FILTERS, ATMOSPHERIC DENSITY,...
The semi-annual variation in the thermospheric density is discussed in terms of the spatial and temporal variations in the solar heat input. Two heat sources are considered: the solar heat input associated with the semi-annual migration of the sun, and the auroral heat associated with the semi-annual component in magnetic storms. It is shown that the relatively large global component in the semi-annual effect of the total mass density can be explained by the lack of advective loss which...
Topics: NASA Technical Reports Server (NTRS), ANNUAL VARIATIONS, ATMOSPHERIC DENSITY, THERMOSPHERE,...
782
782
May 23, 2011
05/11
by
NON
texts
eye 782
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comment 0
The NASA Propagation Experimenters (NAPEX) meeting is convened each year to discuss studies supported by the NASA Propagation Program. Representatives from the satellite communications industry, academia and government who have an interest in space-ground radio wave propagation are invited to NAPEX meetings for discussions and exchange of information. The reports delivered at this meeting by program managers and investigators present recent activities and future plans. This forum provides an...
Topics: INTERNATIONAL SPACE STATION, ACCELERATION (PHYSICS), NEUTRAL ATMOSPHERES, ATMOSPHERIC DENSITY,...
This monograph replaces a monograph on the upper atmosphere which was a computerized version of Jacchia's model. The current model has a range from 90 to 2500 km. In addition to the computerized model, a quick-look prediction method is given that may be used to estimate the density for any time and spatial location without using a computer.
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC DENSITY, ATMOSPHERIC MODELS, ATMOSPHERIC...
This report covers research undertaken to verify and improve models of atmospheric density fluctuations in the regions of the magnetic cusp, where increased electromagnetic activity can correspond to a cusp upwelling which can double the atmospheric density at altitudes of up to 400km, relevant to satellite drag orbits.. The grant funded a field trip in January 2013 to Svalbard for a joint optical/radar experiment to augment the first case study from January 2012. Two Fabry-Perot...
Topics: DTIC Archive, UNIVERSITY COLL LONDON (UNITED KINGDOM), *ATMOSPHERIC DENSITY, ARTIFICIAL SATELLITES,...
Our modern technology-based society relies on satellite communications. Consequently more and more satellites are sent into orbit by an increasing number of countries for both commercial and military purposes. The cost of each satellite can be a few hundred million dollars, and the information that they deliver can be commercially valuable and sensitive. This increases the pressure on high quality orbit determination, which requires reliable models of the behaviour of the upper atmosphere. The...
Topics: DTIC Archive, UNIVERSITY COLL LONDON (UNITED KINGDOM) DEPT OF PHYSICS AND ASTRONOMY, *SATELLITE...
The composition and structure of the atmosphere of Titan, based on theory and on spectroscopic and infrared data, is reviewed for the development of numerical engineering models. Light, nominal, and heavy atmospheres are described and tabulated, and their profiles of radius, temperature, pressure, and density are illustrated. Corresponding descriptions of atmospheric dynamics, condensates and surfaces are outlined.
Topics: NASA Technical Reports Server (NTRS), NATURAL SATELLITES, SATURN (PLANET), ATMOSPHERIC DENSITY,...
In order to study possible perturbations of the ROBIN density calculations, a consistent set of velocities was computed between 70 km and 38 km for a standard atmosphere using simplified fall velocity equations. Consistency was achieved by iterating the calculations until variations in the drag coefficient produced insignificant changes in the fall velocities. Fall velocities were then computed using an equation that in cluded an arbitrary distribution of vertical atmospheric motions. The...
Topics: DTIC Archive, Kern, L C, RAND CORP SANTA MONICA CA, *ATMOSPHERIC MOTION, *ATMOSPHERIC DENSITY,...
This analysis expresses in quantitative terms formulae for describing the various phenomena associated with what astronomers conventionally term atmospheric seeing. This leads to a study of the effect of various convective and in homogeneous layers on the path of a ray of light. The quantitative results are discussed as ap plied to three distinct regions of the atmos phere. First is the internal or instrumental heating, particularly hazardous for solar ob servation. The second critical zone...
Topics: DTIC Archive, Menzel, Donald H, HARVARD COLL OBSERVATORY CAMBRIDGE MA SOLAR DEPT, *AIR,...
This paper briefly summarizes the development of empirical models of the geomagnetic variation in the thermosphere and exosphere. The earliest models were based exclusively on the results of satellite drag analysis. Although they present a much simplified picture of what is an extremely complex phenomenon, these models are still valid in many applications and remain in wide use. They do, however, leave much to be desired with respect to short-term accuracy and are quite inadequate in many cases...
Topics: DTIC Archive, Slowey, Jack W., SMITHSONIAN ASTROPHYSICAL OBSERVATORY CAMBRIDGE MA, *ATMOSPHERIC...
The results of solar radiation observations in the extreme ultra-violet spectrum from 200 A to 600 A made by the OSO-7 Satellite were studied. The results of the influence of attenuation by the atmosphere in the 250 to 500 km altitude range are presented. Using published molecular absorption cross-sections at 304 A and 256 A, the Jaccia atmospheric model is validated, and shows that a mean exospheric of 1050 K is appropriate for the sunset data.
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC DENSITY, NITROGEN, OSO-7, OXYGEN, ULTRAVIOLET...
257
257
Jul 23, 2010
07/10
by
NON
texts
eye 257
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Publications of research sponsored by the NASA CELSS (Controlled Ecological Life Support Systems) Program are listed, along with publications of interest to the Program. The bibliography is divided into the three major divisions of CELSS research: (1) Food Production; (2) Waste Management; and (3) Systems Management and Control. This bibliography is an update of NASA CR-3911 and includes references from 1984 through 1986.
Topics: ATMOSPHERIC DENSITY, WIND EFFECTS, DESCENT TRAJECTORIES, REFERENCE ATMOSPHERES, SPACECRAFT CONTROL,...
164
164
Jul 12, 2010
07/10
by
Huson, G. R
texts
eye 164
favorite 0
comment 0
No Abstract Available
Topics: SOLAR RADIATION, X RAY ASTRONOMY, X RAY FLUORESCENCE, ABSORPTION CROSS SECTIONS, ATMOSPHERIC...
Atmospheric density was determined from a singly mounted ionization gauge flown on an Air Force satellite. Included is a brief description of the experiment and theory as well as a discussion of some of the problems involved in performing these measurements. Density data are given for the altitude range of 370 to 400 km during early morning hours for the two days 17 and 18 June 1961. Results are compared with those of the 1961 revised U.S. Standard Atmosphere.
Topics: DTIC Archive, McIsaac, J, AIR FORCE CAMBRIDGE RESEARCH LABS HANSCOM AFB MA, *ATMOSPHERIC DENSITY,...
Many aspects of a satellite mission are directly impacted by the ability to precisely determine and accurately predict the satellite's orbit through high precision orbit determination. While gravity forces are typically well understood, the modeling of non-conservative forces to a high precision, which is critical to high precision orbit determination of satellites in low Earth orbit, is often more challenging. A number of current and historically recommended atmospheric density models are...
Topics: DTIC Archive, NAVAL RESEARCH LAB WASHINGTON DC, *GEODETIC SATELLITES, ATMOSPHERE MODELS,...
579
579
Jul 11, 2010
07/10
by
Cooper, P. A.; Dexter, C. B
texts
eye 579
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Small geometric imperfections in thin-walled shell structures can cause large reductions in buckling strength. Most imperfections found in structures are neither axisymmetric nor have the shape of buckling modes but rather occur locally. This report presents the results of a study of the effect of local imperfections on the critical buckling load of a specific axially compressed thin-walled conical shell. The buckling calculations were performed by using a two-dimensional shell analysis program...
Topics: DIURNAL VARIATIONS, WIND (METEOROLOGY), EQUINOXES, THERMOSPHERE, ATMOSPHERIC DENSITY, ATMOSPHERIC...
535
535
Jun 27, 2010
06/10
by
Jones, W. L.; Sivo, J. N.; Wanhainen, J. P
texts
eye 535
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comment 0
No Abstract Available
Topics: ATMOSPHERIC ATTENUATION, DIURNAL VARIATIONS, ATMOSPHERIC MODELS, DETECTION, EARTH RESOURCES...
A major part of the work performed under this contract has been directed toward engineering development, fabrication, testing, calibration and field testing of improved AFGL rocketborne falling sphere systems used to determine accurately atmospheric density within the altitude range 35-150 km. In this report a summary is given of rocket launches carried out at various sites using hardware and instrumentation developed and fabricated under this contract. The effort included engineering and field...
Topics: DTIC Archive, Ebacher,R W, WENTWORTH INST BOSTON MA, *ACCELEROMETERS, *ATMOSPHERIC DENSITY,...
292
292
Jun 13, 2011
06/11
by
Heath, Stephanie L.; McAninch, Gerry L
texts
eye 292
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Propagation characteristics for varying wind and temperature atmospheric conditions are identified using physically-limiting propagation angles to define shadow boundary regions. These angles are graphically illustrated for various wind and temperature cases using a newly developed ray-tracing propagation code.
Topics: SOFT LANDING, ATMOSPHERIC DENSITY, OPTICAL RADAR, SPACE EXPLORATION, ROVING VEHICLES, MARS...
Neutral density data were obtained near 400 km (1600 LT) from a microphone density gage on OGO-6 from 0 to 40 deg N geomagnetic latitude for 25 September through 3 October 1969. Several geomagnetic storms occurred during this period. Least squares fits were made to data points on density scatter diagrams. An equation representing the least squares fit was computed for each delay time. The equation of best fit (and the corresponding time delay between the density and the magnetic index which...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC DENSITY, MAGNETIC STORMS, OGO-6, UPPER...
Ground and space measurements of the solar spectral irradiance at radio, visible, UV, and X ray wavelengths show a large decline in the first 6 months of 1992. This sustained drop in the solar output is important in understanding the connection between the emergent magnetic flux on the Sun and the radiative output as well as in understanding the effects of such change in the upper atmosphere of the earth. We present preliminary estimates of the observed changes as the means to spur inquiry into...
Topics: DTIC Archive, White, O R, PHILLIPS LAB HANSCOM AFB MA, *SOLAR SPECTRUM, *EARTH ATMOSPHERE,...
Due to poor atmospheric density models for computing drag forces on satellites, AF Space Battlelab approved the initiative MADM. The Modified Atmospheric Density Model's objective is to update an atmospheric density model in near real-time using satellite-tracking data. This is accomplished by attempting to apply intelligent feedback from the empirical drag data for satellites in stable orbits to correct the overall atmospheric model density error. MADM uses an engineering approach, opposed to...
Topics: DTIC Archive, Roberts, Darren J, AIR FORCE SPACE BATTLELAB SHRIEVER AFBCO, *ATMOSPHERE MODELS,...
This contract supported investigations of integrated applications of physics, ephemerides, and mathematics of the atmosphere and near space. Projects undertaken and reported include spacecraft, ionospheric, atmospheric, and astronomical circumstances; data based studies of air combat targeting; meteorology including cloud scene simulation and ITASCA expert system; ionospheric scintillations; atmospheric metal deposition; auroral particle and electric field modeling, magnetic field studies for...
Topics: DTIC Archive, Ayer, S. M., RADEX INC BEDFORD MA, *COMPUTERIZED SIMULATION, *PREDICTIONS,...
The 80 to 130 km altitude region is our old ignorosphere, the region of the atmosphere that no one seems to be interested in and yet the critical region for shuttle entry and atmospheric braking. Comparison between the Air Force reference atmosphere and Shuttle Inertial Measurement Units data shows large fluctuations at high latitudes. New data sources are available now, such as the Arecibo and Millstone Hill ionospheric scatter radars. In the 20 to 80 km altitude range there is a reasonable...
Topics: NASA Technical Reports Server (NTRS), AEROBRAKING, ATMOSPHERIC DENSITY, ATMOSPHERIC MODELS, MIDDLE...
The Global Reference Atmosphere Model (GRAM) is under continuous development and improvement. GRAM data were compared with Middle Atmosphere Program (MAP) predictions and with shuttle data. An important note: Users should employ only step sizes in altitude that give vertical density gradients consistent with shuttle-derived density data. Using too small a vertical step size (finer then 1 km) will result in what appears to be unreasonably high values of density shears but what in reality is...
Topics: NASA Technical Reports Server (NTRS), ATMOSPHERIC DENSITY, ATMOSPHERIC MODELS, MIDDLE ATMOSPHERE,...
