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Sample records for artificial earth satellites

  1. Optical Studies of Artificial Earth Satellites

    ERIC Educational Resources Information Center

    Richards, D. A.

    1973-01-01

    Discusses the visual and photographic methods and the design features of a camera at Aberystwyth with a brief justification for satellite tracking. Indicates that satellite measurements have been used to determine the shape of the earth and diurnal variations in atmospherical densities. (CC)

  2. First optical observations of artificial Earth's satellites

    NASA Astrophysics Data System (ADS)

    Rykhlova, L. V.

    2008-08-01

    A review of the first optical observations of the artificial satellites in the USSR as well as in former communist countries (DDR, Romania,Poland) is given. The role by Alla G. Masevich, I.D. Zhongolovich and Yu.V. Batrakov is underlined in the organization of observations.

  3. Multifunctional astronomical self-organizing system of autonomous navigation and orientation for artificial Earth satellites

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. I.; Danilova, T. V.

    2017-03-01

    We describe the methods and algorithms of a multifunctional astronomical system of the autonomous navigation and orientation for artificial Earth satellites based on the automatization of the system approach to the design and programming problems of the subject area.

  4. Long-term dynamics of artificial Earth satellites

    NASA Astrophysics Data System (ADS)

    Skoulidou, D. K.; Rosengren, A. J.; Tsiganis, K.; Voyatzis, G.

    2017-03-01

    We present a numerical investigation of the coupled gravitational and nongravitational perturbations acting on Earth satellite orbits in the whole circumterrestrial space, using a suitably modified version of the SWIFT symplectic integration package. We characterize the dynamical architecture of the Earth-orbiting environment from low-Earth orbits up to the supersynchronous regime, with a particular focus on the drag-free range of semimajor axes where the effects of oblateness and lunisolar forces are comparable. The results are contained within an atlas of stability maps, which accurately depict the phase-space structure near orbital resonances. This work complements previous studies based on simplified averaged models, and leads to a better understanding of the dynamical environments occupied by satellites and space debris.

  5. Approximate analytic method for high-apogee twelve-hour orbits of artificial Earth's satellites

    NASA Astrophysics Data System (ADS)

    Vashkovyaka, M. A.; Zaslavskii, G. S.

    2016-09-01

    We propose an approach to the study of the evolution of high-apogee twelve-hour orbits of artificial Earth's satellites. We describe parameters of the motion model used for the artificial Earth's satellite such that the principal gravitational perturbations of the Moon and Sun, nonsphericity of the Earth, and perturbations from the light pressure force are approximately taken into account. To solve the system of averaged equations describing the evolution of the orbit parameters of an artificial satellite, we use both numeric and analytic methods. To select initial parameters of the twelve-hour orbit, we assume that the path of the satellite along the surface of the Earth is stable. Results obtained by the analytic method and by the numerical integration of the evolving system are compared. For intervals of several years, we obtain estimates of oscillation periods and amplitudes for orbital elements. To verify the results and estimate the precision of the method, we use the numerical integration of rigorous (not averaged) equations of motion of the artificial satellite: they take into account forces acting on the satellite substantially more completely and precisely. The described method can be applied not only to the investigation of orbit evolutions of artificial satellites of the Earth; it can be applied to the investigation of the orbit evolution for other planets of the Solar system provided that the corresponding research problem will arise in the future and the considered special class of resonance orbits of satellites will be used for that purpose.

  6. Auxiliary subprograms for calculating the navigational parameters of artificial Earth satellites. FORTRAN IV

    NASA Technical Reports Server (NTRS)

    Prokhorenko, V. I.

    1981-01-01

    Subprograms for transforming coordinates and time, for determining the position of the Moon and Sun, and for calculating the atmosphere and disturbances, which are specified by anomalies of the Earth's gravitational field are described. The subprograms are written in FORTRAN IV and form a major part of the package of applied programs for calculating the navigational parameters of artificial Earth satellites.

  7. Communication Systems through Artificial Earth Satellites (Selected Pages)

    DTIC Science & Technology

    1987-02-05

    82173X& 4, p. 975 --1238. 7. rerua8itea r. r., Kajiaw1HnKon H. H., Bw~ioa B. Af. It Ap. Pe- ZyJnbTaThi 3xcnepHueHTa no PaAHOCaaa3H ’epes 3xo-2 H .flyny...second method of radio communication, with which on board satellite there will not be radio equipment, but signals, sent from point/item A, will be...in the first version, but with a sufficient antenna gain and the sensitive receivers this method in a number of cases is DOC = 86120401 PAGE 11 Q

  8. Data fusion with artificial neural networks (ANN) for classification of earth surface from microwave satellite measurements

    NASA Technical Reports Server (NTRS)

    Lure, Y. M. Fleming; Grody, Norman C.; Chiou, Y. S. Peter; Yeh, H. Y. Michael

    1993-01-01

    A data fusion system with artificial neural networks (ANN) is used for fast and accurate classification of five earth surface conditions and surface changes, based on seven SSMI multichannel microwave satellite measurements. The measurements include brightness temperatures at 19, 22, 37, and 85 GHz at both H and V polarizations (only V at 22 GHz). The seven channel measurements are processed through a convolution computation such that all measurements are located at same grid. Five surface classes including non-scattering surface, precipitation over land, over ocean, snow, and desert are identified from ground-truth observations. The system processes sensory data in three consecutive phases: (1) pre-processing to extract feature vectors and enhance separability among detected classes; (2) preliminary classification of Earth surface patterns using two separate and parallely acting classifiers: back-propagation neural network and binary decision tree classifiers; and (3) data fusion of results from preliminary classifiers to obtain the optimal performance in overall classification. Both the binary decision tree classifier and the fusion processing centers are implemented by neural network architectures. The fusion system configuration is a hierarchical neural network architecture, in which each functional neural net will handle different processing phases in a pipelined fashion. There is a total of around 13,500 samples for this analysis, of which 4 percent are used as the training set and 96 percent as the testing set. After training, this classification system is able to bring up the detection accuracy to 94 percent compared with 88 percent for back-propagation artificial neural networks and 80 percent for binary decision tree classifiers. The neural network data fusion classification is currently under progress to be integrated in an image processing system at NOAA and to be implemented in a prototype of a massively parallel and dynamically reconfigurable Modular

  9. The Near-Earth Space Surveillance (NESS) Mission: Discovery, Tracking, and Characterization of Asteroids, Comets, and Artificial Satellites with a Microsatellite

    NASA Technical Reports Server (NTRS)

    Hildebrand, A. R.; Carroll, K. A.; Balam, D. D.; Cardinal, R. D.; Matthews, J. M.; Kuschnig, R.; Walker, G. A. H.; Brown, P. G.; Tedesco, E. F.; Worden, S. P.

    2001-01-01

    The Near-Earth Space Surveillance (NESS) Mission, a microsatellite dedicated to observing near-Earth (NEO) and interior-to-the-Earth (IEO)asteroids and comets plus artificial satellites, is currently being studied under contract to the Canadian Space Agency. Additional information is contained in the original extended abstract.

  10. Periodic components of the atmospheric drag of Earth artificial satellites and their dependence on the state of space weather

    NASA Astrophysics Data System (ADS)

    Komendant, Volodymyr; Koshkin, Nikolay; Ryabov, Mikhail

    2016-07-01

    Based on the accumulated in the University Observatory extensive database of evolving orbital elements of low-orbit satellites, the behavior of the parameterwas studied, which characterizes their drag in the atmosphere of the Earth. The time spectra structure of drag of 25 artificial satellites is being studied by applying various methods of spectral analysis. Fifteen artificial satellites with circular orbits and ten artificial satellites with elliptical orbits are studied. The processed information includes ten years of observations that covers: declining and minimum phases of 23 ^{rd}(2005-2008) solar cycle; phases of rise and maximum of 24th(2009-2014) solar cycle. Time-frequency analysis of solar and geomagnetic activity indexes has been conducted. These indexes are: W - Wolf numbers; Sp - the total area of sunspot groups of the northern and southern hemispheres of the Sun, F10.7 - the solar radio flux at 10,7 cm; E - electron flux with energies more than 0,6 MeV i 2 MeV; planetary, high latitude and middle latitude geomagnetic index Ap. Periodograms of satellite's drag data, solar and geomagnetic activity indexes were constructed. In the atmospheric drag dynamics of satellites,the following periodswere detected: 6-year, 2.1-year, annual, semi-annual, 27-days, 13- and 11-days. Similar periods are identified in indexes of solar and geomagnetic activity. The ratios of the amplitudes of the spectral power of these periods vary in different phases of the solar cycle. The tables of the main periods in the drag of the artificial satellites and the main periods in the solar and geomagnetic activity indexes were obtained with the help of spectrograms. Their presence in certain phases of the solar cycle was researched. The calculation of multiple correlation' models of the orbital parameter characterizing the drag of satellites on various orbits, depending on the basic parameters of space weather has been done. These results have practical application for models

  11. Artificial Earth Satellites Designed and Fabricated by The Johns Hopkins University Applied Physics Laboratory. Revised

    DTIC Science & Technology

    1978-07-01

    until propellant exhaustion on 18 April 1975 , exceeding substantially its one-year design life. Experiments with an orbital prediction span of up to two...UWafeinS APPLIED PHYSICS LABORATORY SDO 1600 -- May 1975 I. 3 Appendix B THE NAVY NAVIGATION SATELLITE SYSTEM! One of the earliest programs designed to...SDO-1600 7 (Revised)lCL SARTIFICIAL EARTH SATELLITEStQ DESIGNED AND FABRICATED 9 by I THE JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY I __CD

  12. Effect of Oblateness of an Artificial Satellite on the Orbits Around the Triangular Points of the Earth-Moon System in the Axisymmetric ER3BP

    NASA Astrophysics Data System (ADS)

    Singh, Jagadish; Umar, Aishetu

    2017-01-01

    Using a semi-analytic approach, the effect of oblateness of an artificial satellite on the periodic orbits around the triangular Lagrangian points of the Earth-Moon system is studied. The primaries in this system move in elliptic orbits about their common barycenter, hence we have an elliptic restricted three-body problem. The frequencies of the long and short orbits of the periodic motion are affected by the oblateness of the primaries (Earth and Moon) and of the third body (artificial satellite); and so are their eccentricities, semi-major and semi-minor axes.

  13. Flights to asteroids from the orbit of an artificial earth satellite with a perturbational-aerodynamical impulse maneuver near Mars

    NASA Astrophysics Data System (ADS)

    Livanov, L. B.

    1992-06-01

    A spacecraft leaves the low orbit of an artificial earth satellite and, approaching Mars, descends, making the first half of a perturbational maneuver. Then the spacecraft slows down somewhat while flying in the Martian atmosphere at a constant altitude with a constant L/D(sc) less than 2.4. On some spacecraft launch dates in the time span from 1970 to 2020 a velocity impulse to about 2 km/s may be required upon exit from the atmosphere in the case of an optimal choice of dates for earth-Mars and Mars-asteroids flights. Then the spacecraft ascends over Mars, completing the second half of the perturbational maneuver. On the spacecrafts approach to the target asteroid, impulse equalization of the velocities of the spacecraft and the asteroid occurs. The sum of the three impulses - at the earth, Mars, and the asteroid - is usually 2 to 3 km/s less than the sum of the impulses required with direct optimal-trajectory earth-asteroid flights on the best dates in the same launch time span.

  14. Communications via the radio artificial earth satellite: Design of the tracking diagram and features for conducting QSO

    NASA Technical Reports Server (NTRS)

    Dobrozhanskiy, V.; Rybkin, V.

    1980-01-01

    A detailed examination is made of the operation of a transmitting artifical Earth satellite. A tracking diagram for the satellite is constructed. The zone of radio visibility can be determined based on the techniques proposed.

  15. Evolution of the rotation of an artificial earth satellite under the influence of a perturbing moment which is constant in fixed axes

    NASA Technical Reports Server (NTRS)

    Neyshtadt, A. I.; Pivovarov, M. L.

    1979-01-01

    The change in the modulus of the vector of the kinetic moment of a satellite which is noted during the determination of the actual orientation of an artificial earth is discussed. The change is due to the presence of a small perturbing moment, which is constant in fixed axes relative to the satellite. It is also shown that the averaged equations in this problem can be integrated.

  16. On the nature of the radial and cross track errors for artificial earth satellites. [GEOS 2 and OAR-901

    NASA Technical Reports Server (NTRS)

    Bonavito, N. L.; Gordon, R. A.; Marsh, J. G.

    1975-01-01

    The analysis of the radial and cross track errors of artificial earth satellites is discussed in terms of the interference of two one-dimensional celestial mechanical wave trains. Resulting equations for these tracking errors describe the behavior of the uncertainties in the orbital parameters as oscillatory in nature, with a rapidly oscillating term, which is a function of the sum of the observed and computed orbital frequencies, modulated in amplitude by a slowly varying oscillation. This latter term is itself a function of either the difference between these orbital frequencies or between the values of the computed and observed right ascensions, depending upon whether it is the radial or cross track case under consideration. These results indicate that the cross track calculation describes the behavior of uncertainties in the right ascension of the ascending node and the inclination, while the radial calculation gives information on uncertainties in the semi-major axis, the eccentricity, and the argument of perigee. In addition, expressions for the radial and cross track oscillatory frequencies are obtained in terms of the orbital frequencies of the satellites. Data show that the time average of the radial and cross track errors in any case, will both approach zero.

  17. Exploring the possibility of following the movements of a bird from an artificial earth satellite

    NASA Technical Reports Server (NTRS)

    Mackay, R. S.

    1974-01-01

    The development of a harness to hold the transmitter is discussed along with satellite systems for monitoring the flight paths of the birds, and incorporating biological information into the tracking signal.

  18. Dniper duplicate of launch of the first artificial satellite of the Earth

    NASA Astrophysics Data System (ADS)

    Prisniakov, V. F.; Kavelin, S. S.; Platonov, V. P.

    2009-11-01

    The report opens little-known page of a history of the space technology, connected with launching of the first Soviet satellite. In the USSR practically ready and spare variant of launch by rocket R12 Kosmos of DB Pivdenne was. This development, became a push for a space direction in Dnipropetrovsk. The idea of creation of the satellite launcher on basis of combat missile was extremely fruitful. Terms and the cost of development were essentially reduced and operation of a space rocket complex became simpler. Paper is describing about the unknown events connected to development of rocket R-12 which on March, 16, 1962 has defined the beginning of the Ukrainian space age after launching of satellite "Kosmos" and about M.K. Tihonravov who has proved a reality of launching of the satellite in the USSR. Since October, 14, 1969 satellite launcher 63C1 started to place in orbit the international satellites of series Interkosmos. For 15 years of its operation, 165 launches have been made of them 143 was successful. Spacecraft under the name Kosmos1 placed in orbit became the founder of huge family of the diverse space vehicles of SDB 586 which number has come nearer to figure 400.

  19. On the determination of the long period tidal perturbations in the elements of artificial earth satellites

    NASA Technical Reports Server (NTRS)

    Musen, P.; Felsentreger, T.

    1972-01-01

    The magnitude of the tidal effects depends upon the elastic properties of the earth as described by Love numbers. The Love numbers appear as the coefficients in the expansion of the exterior tidal potential in terms of spherical harmonics (in Maxwellian form). A single averaging process was performed only along the parallels of latitude. This process preserves additional long period tidal effects (with periods of a few days or more). It also eliminates the short period effects with periods of one day or less.

  20. A semi-analytic theory for the motion of a close-earth artificial satellite with drag

    NASA Technical Reports Server (NTRS)

    Liu, J. J. F.; Alford, R. L.

    1979-01-01

    A semi-analytic method is used to estimate the decay history/lifetime and to generate orbital ephemeris for close-earth satellites perturbed by the atmospheric drag and earth oblateness due to the spherical harmonics J2, J3, and J4. The theory maintains efficiency through the application of the theory of a method of averaging and employs sufficient numerical emphasis to include a rather sophisticated atmospheric density model. The averaged drag effects with respect to mean anomaly are evaluated by a Gauss-Legendre quadrature while the averaged variational equations of motion are integrated numerically with automatic step size and error control.

  1. Orbital Dynamics of Space Debris around operational artificial satellites

    NASA Astrophysics Data System (ADS)

    Sampaio, Jarbas

    2016-07-01

    The increasing number of space debris, orbiting the Earth justifies and requires more efforts to observe and track them to avoid collisions among them and the earth's satellites. In this way, several studies are important to preserve the operability of the artificial satellites. In this work, the orbital dynamics of space debris are studied in the neighborhood of operational artificial satellites. The results show that the collision risks between these objects is high and solutions to avoid these events are necessary.

  2. Conjunction Risks of Near-Earth Objects to Artificial Satellites: The Case of Asteroid 2015 VY105

    NASA Astrophysics Data System (ADS)

    Ryan, W.; Ryan, E.

    2016-09-01

    The close approach of near-Earth object 2015 VY105 on November 15, 2015 occurred less than 24 hours after discovery by the Catalina Sky Survey (located in Tucson, AZ). Based on the discovery metric information and follow up data from Magdalena Ridge Observatory (MRO) observations, it was clear that this asteroid would pass through the geostationary satellite belt. In particular, data indicated that although 2015 VY105 would come within approximately 200 km of the DirectTV 11 and 14 satellites, it would not impact either. The details of this analysis as well as characterization results acquired are presented. Further, examples of various other asteroids that have made close approaches within geostationary distances in the past (with both long and short lead times) are included for risk context.

  3. Spore-Forming Thermophilic Bacterium within Artificial Meteorite Survives Entry into the Earth's Atmosphere on FOTON-M4 Satellite Landing Module.

    PubMed

    Slobodkin, Alexander; Gavrilov, Sergey; Ionov, Victor; Iliyin, Vyacheslav

    2015-01-01

    One of the key conditions of the lithopanspermia hypothesis is that microorganisms situated within meteorites could survive hypervelocity entry from space through the Earth's atmosphere. So far, all experimental proof of this possibility has been based on tests with sounding rockets which do not reach the transit velocities of natural meteorites. We explored the survival of the spore-forming thermophilic anaerobic bacterium, Thermoanaerobacter siderophilus, placed within 1.4-cm thick basalt discs fixed on the exterior of a space capsule (the METEORITE experiment on the FOTON-M4 satellite). After 45 days of orbital flight, the landing module of the space vehicle returned to Earth. The temperature during the atmospheric transit was high enough to melt the surface of basalt. T. siderophilus survived the entry; viable cells were recovered from 4 of 24 wells loaded with this microorganism. The identity of the strain was confirmed by 16S rRNA gene sequence and physiological tests. This is the first report on the survival of a lifeform within an artificial meteorite after entry from space orbit through Earth's atmosphere at a velocity that closely approached the velocities of natural meteorites. The characteristics of the artificial meteorite and the living object applied in this study can serve as positive controls in further experiments on testing of different organisms and conditions of interplanetary transport.

  4. Imaging artificial satellites: An observational challenge

    NASA Astrophysics Data System (ADS)

    Smith, D. A.; Hill, D. C.

    2016-10-01

    According to the Union of Concerned Scientists, as of the beginning of 2016 there are 1381 active satellites orbiting the Earth, and the United States' Space Surveillance Network tracks about 8000 manmade orbiting objects of baseball-size and larger. NASA estimates debris larger than 1 cm to number more than half a million. The largest ones can be seen by eye—unresolved dots of light that move across the sky in minutes. For most astrophotographers, satellites are annoying streaks that can ruin hours of work. However, capturing a resolved image of an artificial satellite can pose an interesting challenge for a student, and such a project can provide connections between objects in the sky and commercial and political activities here on Earth.

  5. Artificial asteroid impact on defensive satellites

    SciTech Connect

    Canavan, G.H.

    1989-03-01

    Given the large projected Soviet space lift capacity, it is useful to ask whether its placing large amounts of mass in near-earth orbits could present a serious impediment to defensive satellites deployed there. This report uses a simple model to show that such artificial asteroid belts are feasible and could directly limit the rate of deployment of defensive satellites in the near term, but are not necessarily an attractive, use of that lift capacity in the long term. 7 refs., 6 figs.

  6. Aqua satellite orbiting the Earth

    NASA Video Gallery

    This animation shows the Aqua satellite orbiting the Earth on August 27, 2005 by revealing MODIS true-color imagery for that day. This animation is on a cartesian map projection, so the satellite w...

  7. Spore-Forming Thermophilic Bacterium within Artificial Meteorite Survives Entry into the Earth's Atmosphere on FOTON-M4 Satellite Landing Module

    PubMed Central

    Slobodkin, Alexander; Gavrilov, Sergey; Ionov, Victor; Iliyin, Vyacheslav

    2015-01-01

    One of the key conditions of the lithopanspermia hypothesis is that microorganisms situated within meteorites could survive hypervelocity entry from space through the Earth’s atmosphere. So far, all experimental proof of this possibility has been based on tests with sounding rockets which do not reach the transit velocities of natural meteorites. We explored the survival of the spore-forming thermophilic anaerobic bacterium, Thermoanaerobacter siderophilus, placed within 1.4-cm thick basalt discs fixed on the exterior of a space capsule (the METEORITE experiment on the FOTON-M4 satellite). After 45 days of orbital flight, the landing module of the space vehicle returned to Earth. The temperature during the atmospheric transit was high enough to melt the surface of basalt. T. siderophilus survived the entry; viable cells were recovered from 4 of 24 wells loaded with this microorganism. The identity of the strain was confirmed by 16S rRNA gene sequence and physiological tests. This is the first report on the survival of a lifeform within an artificial meteorite after entry from space orbit through Earth’s atmosphere at a velocity that closely approached the velocities of natural meteorites. The characteristics of the artificial meteorite and the living object applied in this study can serve as positive controls in further experiments on testing of different organisms and conditions of interplanetary transport. PMID:26151136

  8. Electromagnetic deep-probing (100-1000 kms) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

    NASA Technical Reports Server (NTRS)

    Hermance, J. F.

    1983-01-01

    The reconnaissance phase of using satellite observtions to studying electromagnetic induction in the solid earth is summarized. Several points are made: (1) satellite data apparently suffer far less from the effects of near surface lateral heterogeneities in the earth than do ground-based data; (2) zonal ionospheric currents during the recovery phase of major magnetic storms appear to be minimal, at least in the dawn and dusk sectors wher MAGSAT was flown; hence the internal contributions that satellites observe during these times is in fact due primarily to induction in the Earth with little or no contribution from ionospheric currents; and (3) the interpretation of satellite data in terms of primitive electromagnetic response functions, while grossly over-simplified, results in a surprisingly well-resolved radius for an equivalent super-conductor representing the conductivity region of the Earth's interior (5,370 + or - 120 km).

  9. Electromagnetic deep-probing (100-1000 KMS) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

    NASA Technical Reports Server (NTRS)

    Hermance, J. F. (Principal Investigator)

    1981-01-01

    Model simulations show that induction in a spherical Earth by distant magnetospheric sources can contribute magnetic field fluctuations at MAGSAT altitudes which are 30 to 40 percent of the external field amplitudes. When the characteristic dimensions (e.g. depth of penetration, etc) of a particular situations are small compared with the Earth's radius, the Earth can be approximated by a plane horizontal half space. In this case, electromagnetic energy is reflected with close to 100 percent efficiency from the Earth's surface. This implies that the total horizontal field is twice the source field when the source is above the satellite, but is reduced to values which are much smaller than the source field when the source is below the satellite. This latter effect tends to enhance the signature of gross electrical discontinuities in the lithosphere when observed at satellite altitudes.

  10. Electromagnetic deep-probing (100-1000 KMS) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

    NASA Technical Reports Server (NTRS)

    Hermance, J. F. (Principal Investigator)

    1981-01-01

    An algorithm was developed to address the problem of electromagnetic coupling of ionospheric current systems to both a homogeneous Earth having finite conductivity, and to an Earth having gross lateral variations in its conductivity structure, e.g., the ocean-land interface. Typical results from the model simulation for ionospheric currents flowing parallel to a representative geologic discontinuity are shown. Although the total magnetic field component at the satellite altitude is an order of magnitude smaller than at the Earth's surface (because of cancellation effects from the source current), the anomalous behavior of the satellite observations as the vehicle passes over the geologic contact is relatively more important pronounced. The results discriminate among gross lithospheric structures because of difference in electrical conductivity.

  11. Spanish Earth Observation Satellite System

    NASA Astrophysics Data System (ADS)

    Borges, A.; Cerezo, F.; Fernandez, M.; Lomba, J.; Lopez, M.; Moreno, J.; Neira, A.; Quintana, C.; Torres, J.; Trigo, R.; Urena, J.; Vega, E.; Vez, E.

    2010-12-01

    The Spanish Ministry of Industry, Tourism and Trade (MITyC) and the Ministry of Defense (MoD) signed an agreement in 2007 for the development of a "Spanish Earth Observation Satellite System" based, in first instance, on two satellites: a high resolution optical satellite, called SEOSAT/Ingenio, and a radar satellite based on SAR technology, called SEOSAR/Paz. SEOSAT/Ingenio is managed by MITyC through the Centre for the Development of Industrial Technology (CDTI), with technical and contractual support from the European Space Agency (ESA). HISDESA T together with the Spanish Instituto Nacional de Técnica Aeroespacial (INTA, National Institute for Aerospace Technology) will be responsible for the in-orbit operation and the commercial operation of both satellites, and for the technical management of SEOSAR/Paz on behalf of the MoD. In both cases EADS CASA Espacio (ECE) is the prime contractor leading the industrial consortia. The ground segment development will be assigned to a Spanish consortium. This system is the most important contribution of Spain to the European Programme Global Monitoring for Environment and Security, GMES. This paper presents the Spanish Earth Observation Satellite System focusing on SEOSA T/Ingenio Programme and with special emphasis in the potential contribution to the ESA Third Party Missions Programme and to the Global Monitoring for Environment and Security initiative (GMES) Data Access.

  12. Low Earth orbit communications satellite

    NASA Technical Reports Server (NTRS)

    Moroney, D.; Lashbrook, D.; Mckibben, B.; Gardener, N.; Rivers, T.; Nottingham, G.; Golden, B.; Barfield, B.; Bruening, J.; Wood, D.

    1992-01-01

    A current thrust in satellite communication systems considers a low-Earth orbiting constellations of satellites for continuous global coverage. Conceptual design studies have been done at the time of this design project by LORAL Aerospace Corporation under the program name GLOBALSTAR and by Motorola under their IRIDIUM program. This design project concentrates on the spacecraft design of the GLOBALSTAR low-Earth orbiting communication system. Overview information on the program was gained through the Federal Communications Commission licensing request. The GLOBALSTAR system consists of 48 operational satellites positioned in a Walker Delta pattern providing global coverage and redundancy. The operational orbit is 1389 km (750 nmi) altitude with eight planes of six satellites each. The orbital planes are spaced 45 deg., and the spacecraft are separated by 60 deg. within the plane. A Delta 2 launch vehicle is used to carry six spacecraft for orbit establishment. Once in orbit, the spacecraft will utilize code-division multiple access (spread spectrum modulation) for digital relay, voice, and radio determination satellite services (RDSS) yielding position determination with accuracy up to 200 meters.

  13. Investigations of earth dynamics from satellite observations

    NASA Technical Reports Server (NTRS)

    Gaposchkin, E. M.

    1973-01-01

    The consequences of the earth's elasticity are examined for close-earth satellites. The ideas of polar motion and earth tides are developed in a form applicable to satellite studies, since the polar motion, the body tide, and the ocean tide are all suitable for study by use of satellites. Analysis of available polar-motion data is performed.

  14. Satellite Gravity Drilling the Earth

    NASA Technical Reports Server (NTRS)

    vonFrese, R. R. B.; Potts, L. V.; Leftwich, T. E.; Kim, H. R.; Han, S.-H.; Taylor, P. T.; Ashgharzadeh, M. F.

    2005-01-01

    Analysis of satellite-measured gravity and topography can provide crust-to-core mass variation models for new insi@t on the geologic evolution of the Earth. The internal structure of the Earth is mostly constrained by seismic observations and geochemical considerations. We suggest that these constraints may be augmented by gravity drilling that interprets satellite altitude free-air gravity observations for boundary undulations of the internal density layers related to mass flow. The approach involves separating the free-air anomalies into terrain-correlated and -decorrelated components based on the correlation spectrum between the anomalies and the gravity effects of the terrain. The terrain-decorrelated gravity anomalies are largely devoid of the long wavelength interfering effects of the terrain gravity and thus provide enhanced constraints for modeling mass variations of the mantle and core. For the Earth, subcrustal interpretations of the terrain-decorrelated anomalies are constrained by radially stratified densities inferred from seismic observations. These anomalies, with frequencies that clearly decrease as the density contrasts deepen, facilitate mapping mass flow patterns related to the thermodynamic state and evolution of the Earth's interior.

  15. Earth and ocean dynamics satellites and systems

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.

    1975-01-01

    An overview is presented of the present state of satellite and ground systems making observations of the dynamics of the solid earth and the oceans. Emphasis is placed on applications of space technology for practical use. Topics discussed include: satellite missions and results over the last two decades in the areas of earth gravity field, polar motions, earth tides, magnetic anomalies, and satellite-to-satellite tracking; laser ranging systems; development of the Very Long Baseline Interferometer; and Skylab radar altimeter data applications.

  16. ASAP- ARTIFICIAL SATELLITE ANALYSIS PROGRAM

    NASA Technical Reports Server (NTRS)

    Kwok, J.

    1994-01-01

    The Artificial Satellite Analysis Program (ASAP) is a general orbit prediction program which incorporates sufficient orbit modeling accuracy for mission design, maneuver analysis, and mission planning. ASAP is suitable for studying planetary orbit missions with spacecraft trajectories of reconnaissance (flyby) and exploratory (mapping) nature. Sample data is included for a geosynchronous station drift cycle study, a Venus radar mapping strategy, a frozen orbit about Mars, and a repeat ground trace orbit. ASAP uses Cowell's method in the numerical integration of the equations of motion. The orbital mechanics calculation contains perturbations due to non-sphericity (up to a 40 X 40 field) of the planet, lunar and solar effects, and drag and solar radiation pressure. An 8th order Runge-Kutta integration scheme with variable step size control is used for efficient propagation. The input includes the classical osculating elements, orbital elements of the sun relative to the planet, reference time and dates, drag coefficient, gravitational constants, and planet radius, rotation rate, etc. The printed output contains Cartesian coordinates, velocity, equinoctial elements, and classical elements for each time step or event step. At each step, selected output is added to a plot file. The ASAP package includes a program for sorting this plot file. LOTUS 1-2-3 is used in the supplied examples to graph the results, but any graphics software package could be used to process the plot file. ASAP is not written to be mission-specific. Instead, it is intended to be used for most planetary orbiting missions. As a consequence, the user has to have some basic understanding of orbital mechanics to provide the correct input and interpret the subsequent output. ASAP is written in FORTRAN 77 for batch execution and has been implemented on an IBM PC compatible computer operating under MS-DOS. The ASAP package requires a math coprocessor and a minimum of 256K RAM. This program was last

  17. Korea Earth Observation Satellite Program

    NASA Astrophysics Data System (ADS)

    Baek, Myung-Jin; Kim, Zeen-Chul

    via Korea Aerospace Research Institute (KARI) as the prime contractor in the area of Korea earth observation satellite program to enhance Korea's space program development capability. In this paper, Korea's on-going and future earth observation satellite programs are introduced: KOMPSAT- 1 (Korea Multi Purpose Satellite-1), KOMPSAT-2 and Communication, Broadcasting and Meteorological Satellite (CBMS) program. KOMPSAT-1 satellite successfully launched in December 1999 with Taurus launch vehicle. Since launch, KOMPSAT-1 is downlinking images of Korea Peninsular every day. Until now, KOMPSAT-1 has been operated more than 2 and half years without any major hardware malfunction for the mission operation. KOMPSAT-1 payload has 6.6m panchromatic spatial resolution at 685 km on-orbit and the spacecraft bus had NASA TOMS-EP (Total Ozone Mapping Spectrometer-Earth Probe) spacecraft bus heritage designed and built by TRW, U.S.A.KOMPSAT-1 program was international co-development program between KARI and TRW funded by Korean Government. be launched in 2004. Main mission objective is to provide geo-information products based on the multi-spectral high resolution sensor called Multi-Spectral Camera (MSC) which will provide 1m panchromatic and 4m multi-spectral high resolution images. ELOP of Israel is the prime contractor of the MSC payload system and KARI is the total system prime contractor including spacecraft bus development and ground segment. KARI also has the contract with Astrium of Europe for the purpose of technical consultation and hardware procurement. Based on the experience throughout KOMPSAT-1 and KOMPSAT-2 space system development, Korea is expecting to establish the infrastructure of developing satellite system. Currently, KOMPSAT-2 program is in the critical design stage. are scheduled to launch in 2008 and in 2014, respectively. The mission of CBMS consists of two areas. One is of space technology test for the communications mission, and the other is of a real

  18. Electromagnetic deep-probing (100-1000 kms) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

    NASA Technical Reports Server (NTRS)

    Hermance, J. F. (Principal Investigator)

    1981-01-01

    A spherical harmonic analysis program is being tested which takes magnetic data in universal time from a set of arbitrarily space observatories and calculates a value for the instantaneous magnetic field at any point on the globe. The calculation is done as a least mean-squares value fit to a set of spherical harmonics up to any desired order. The program accepts as a set of input the orbit position of a satellite coordinates it with ground-based magnetic data for a given time. The output is a predicted time series for the magnetic field on the Earth's surface at the (r, theta) position directly under the hypothetically orbiting satellite for the duration of the time period of the input data set. By tracking the surface magnetic field beneath the satellite, narrow-band averages crosspowers between the spatially coordinated satellite and the ground-based data sets are computed. These crosspowers are used to calculate field transfer coefficients with minimum noise distortion. The application of this technique to calculating the vector response function W is discussed.

  19. ON ALIGNMENT OF SUN, EARTH, AND SATELLITE

    DTIC Science & Technology

    The results are reported of an investigation of the relations among the launch parameters of an earth satellite and the time and position of alignment of the sun , the earth, and the satellite. The effects of variations of the launch conditions upon the satellite’s time of transit across the solar disc are determined. (Author)

  20. Low-Earth orbit satellite servicing economics

    NASA Technical Reports Server (NTRS)

    Davis, R. F.; Cepollina, F. J.

    1982-01-01

    Servicing economics of low Earth orbit satellites were studied. The following topics are examined: the economic importance of the repair missions; comparison of mission cost as opposed to satellite modulation transfer functions over a 10 year period; the effect of satellite flight rate change due to changes in satellite failure rate; estimated satellite cost reduction with shuttle operation projects from the 1960's to the 1970's; design objectives of the multimission modular spacecraft; and the economic importance of the repair mission.

  1. Changes in Earth's albedo measured by satellite.

    PubMed

    Wielicki, Bruce A; Wong, Takmeng; Loeb, Norman; Minnis, Patrick; Priestley, Kory; Kandel, Robert

    2005-05-06

    NASA global satellite data provide observations of Earth's albedo, i.e., the fraction of incident solar radiation that is reflected back to space. The satellite data show that the last four years are within natural variability and fail to confirm the 6% relative increase in albedo inferred from observations of earthshine from the moon. Longer global satellite records will be required to discern climate trends in Earth's albedo.

  2. Satellite Earth resources data, module U-3

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Satellite data image products potentially useful in solving Earth resource and environmental problems are described. Sources for satellite data and user information are given. Recommendations for suitability of use of data from each satellite are presented. Satellite sources of Earth resources data are summarized for satellites launched since 1965 and those projected for launch through the late 1980s. The sensors of interest on each satellite, the wavelength or frequency of operation, and the resolution are given. Color ranges are illustrated and compared. The form and utility of aircraft and LANDSAT images are compared. Data from the Gemini-Apollo photography, Skylab, meteorological satellites, the Heat Capacity Mapping Mission, the Coastal Zone Color Scanner, Seasat, LANDSAT, and projected future satellites are briefly described.

  3. Third-order solution of an artificial-satellite theory

    NASA Technical Reports Server (NTRS)

    Kinoshita, H.

    1977-01-01

    A third-order solution was developed for the motions of artificial satellites moving in the gravitational field of the earth, whose potential includes the second-, third-, and fourth-order zonal harmonics. Third-order periodic perturbations with fourth-order secular perturbations were derived by the Hori perturbation method. All quantities were expanded into power series of the eccentricity, but the solution was obtained so as to be closed with respect to the inclination. A comparison with the results of numerical integration of the equations of motion indicates that the solution can predict the position of a close-earth, small-eccentricity satellite with an accuracy of better than one cm over a period of one month.

  4. Artificial satellite break-ups. I - Soviet ocean surveillance satellites

    NASA Astrophysics Data System (ADS)

    Johnson, N. L.

    1983-02-01

    An analysis of the breakup patterns of eight Soviet Kosmos series ocean surveillance satellites is presented. It is noted that half of the 4700 objects presently detected in earth orbit are shards from destroyed objects. The locations and heading of each Soviet satellite breakup were tracked by the Naval Space Survelliance System. All events in the eastern hemisphere occurred in the ascending phase, while western hemisphere breakups happened in the descending phase. Gabbard (1971) diagrams of altitude vs. period are plotted as a function of a fragment's orbital period. The diagrams have been incorporated into a NASA computer program to backtrack along the fragments' paths to determine the pattern of the breakup. Although objects have been projected to have separated from some of the satellites before breakup, a discussion of the evidence leads to the conclusion that even though the satellites may have exploded no purpose can yet be discerned for the actions.

  5. Naked-eye acquisition of visible near-earth satellites

    NASA Technical Reports Server (NTRS)

    Mansfield, Roger L.

    1988-01-01

    This paper develops visual sighting criteria for observing artificial near-earth satellites with the naked eye, and summarizes the mathematics needed to predict visibility efficiently from a set of mean orbital elements. It reports on a successful application of the sighting criteria and visibility-prediction mathematics, and shows that successful visual acquisition depends as much upon the observer's skill in recognizing the constellations as it does upon accurate visibility predictions.

  6. NPP: Why Another Earth-Observing Satellite?

    NASA Video Gallery

    NPP will soon be NASA's newest Earth-observing satellite. To showcase how NPP will be used for both understanding the health of our planet now -- as well as how things might change in the future --...

  7. The Near Earth Object Surveillance Satellite (NEOSSat)

    NASA Astrophysics Data System (ADS)

    Wallace, Brad; Pinkney, Frank L.; Scott, Robert; Bedard, Donald; Rody, Jim; Levesque, Martin P.; Buteau, Sylvie; Racey, Tom; Burrell, Doug; Spaans, Aaron; Hildebrand, Alan

    2004-10-01

    Defence Research and Development Canada (DRDC) and the Canadian Space Agency (CSA) are collaborating to place a microsatellite in low earth orbit to perform optical detection and tracking of both inner-earth orbiting asteroids and earth-orbiting satellites and debris (i.e., "Resident Space Objects", RSOs). The "Near Earth Object Surveillance Satellite (NEOSSat)" will be the first mission for the CSA multi-mission microsatellite bus program, and is intended by DRDC to demonstrate the military utility of this small and inexpensive class of spacecraft. The mission will obtain metric positions, for geosynchronous satellites, to within ±500 m, timestamps accurate to within a millisecond, and be sensitive to objects in geosynchronous orbit down to 14th magnitude. The asteroid tracking mission will repeatedly survey the area from ±45-70° solar elongation with the aim of finding >50% of all inner-earth asteroids having diameters greater than 1 km.

  8. Uplink Power Control For Earth/Satellite/Earth Communication

    NASA Technical Reports Server (NTRS)

    Chakraborty, Dayamoy

    1994-01-01

    Proposed control subsystem adjusts power radiated by uplink transmitter in Earth station/satellite relay station/ Earth station communication system. Adjustments made to compensate for anticipated changes in attenuation by rain. Raw input is a received downlink beacon singal, amplitude of which affected not only by rain fade but also by scintillation, attenuation in atmospheric gases, and diurnal effects.

  9. Satellite Observations of the Earth's Radiation Budget.

    PubMed

    Haar, T H; Suomi, V E

    1969-02-14

    Meteorological satellites have provided the first complete data on energy exchange between earth and space. The planetary albedo is 29 percent for the mean annual case, and the entire earth-atmosphere system is in near radiative equilibrium. More energy is absorbed in tropical regions than previously believed, and major energy source and sink regions exist within latitude belts.

  10. Satellite to study earth's magnetic field

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The Magnetic Field Satellite (Magsat) designed to measure the near earth magnetic field and crustal anomalies is briefly described. A scalar magnetometer to measure the magnitude of the earth's crustal magnetic field and a vector magnetometer to measure magnetic field direction as well as magnitude are included. The mission and its objectives are summarized along with the data collection and processing system.

  11. The Earth's gravity field from satellite geodesy - a 30 year adventure.

    NASA Astrophysics Data System (ADS)

    Rapp, R. H.

    1991-12-01

    The first information on the Earth's gravitational field from artificial satellite observations was published in 1958. The next years have seen a dramatic improvement in the resolution and accuracy of the series representation of the Earth's gravity field. The improvements have taken place slowly taking advantage of improved measurement accuracy and the increasing number of satellites. The proposed ARISTOTELES mission would provide the opportunity to take a significant leap in improving our knowledge of the Earth's gravity field.

  12. NEAs' Satellites Under Close Encounters with Earth

    NASA Astrophysics Data System (ADS)

    Araujo, Rosana; Winter, O. C.

    2012-10-01

    In the present work we took into account the gravitational effects experienced by a NEA (Near-Earth Asteroid), during a close encounter with Earth, in order to estimate the stability regions of NEAs' satellites as a function of the encounter conditions and for different primary-satellite mass ratio values. Initially, the methodology consisted on numerically simulating a system composed by the Sun, the planets of the Solar System, and samples of NEAs belonging to the groups Apollo, Atens and Amor, for a period of 10 Myr. All encounters with Earth closer than 100 Earth's radius were registered. The next step consisted on simulating all those registered close encounters considering the Earth, the asteroid that perform the close encounter, and a cloud of satellites around the asteroid. We considered no-interacting satellites with circular orbits, random values for the inclination, longitude of the ascending node and true anomaly, and with radial distribution going from 0.024 to 0.4 Hill's radius of the asteroid. The largest radial distance for which all the satellites survive (no collision or ejection) is defined as the critical radius. We present a statistical analysis of the registered encounters and the critical radius found, defining the stable regions as a function of the impact parameter - d, and of the relative velocity - V. For the case of massless satellites, we found that all satellites survived for encounters with d>0.3 Earth Hill's radius. For impact parameter d<0.13 Earth Hill's radius, we found that particles with radial distance greater than 0.24 Hill's radius of the asteroid, are unstable, for any relative velocity. The results for the other considered cases will be presented and discussed. We also discuss the implications of the regions found, specially in the NEAs-binary scenarios.

  13. Landsat—Earth observation satellites

    USGS Publications Warehouse

    ,

    2015-11-25

    Since 1972, Landsat satellites have continuously acquired space-based images of the Earth’s land surface, providing data that serve as valuable resources for land use/land change research. The data are useful to a number of applications including forestry, agriculture, geology, regional planning, and education. Landsat is a joint effort of the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA). NASA develops remote sensing instruments and the spacecraft, then launches and validates the performance of the instruments and satellites. The USGS then assumes ownership and operation of the satellites, in addition to managing all ground reception, data archiving, product generation, and data distribution. The result of this program is an unprecedented continuing record of natural and human-induced changes on the global landscape.

  14. Earth resources applications of the Synchronous Earth Observatory Satellite (SEOS)

    NASA Technical Reports Server (NTRS)

    Lowe, D. S.; Cook, J. J.

    1973-01-01

    The results are presented of a four month study to define earth resource applications which are uniquely suited to data collection by a geosynchronous satellite. While such a satellite could also perform many of the functions of ERTS, or its low orbiting successors, those applications were considered in those situations where requirements for timely observation limit the capability of ERTS or EOS. Thus, the application presented could be used to justify a SEOS.

  15. Regulation of low Earth orbit satellites

    NASA Astrophysics Data System (ADS)

    Jayasuriya, Don

    1993-01-01

    Allocation of a number of frequency bands within which low Earth systems could operate was made to the mobile satellite service by the WARC-92 conference. These allocations and their associated inter and intra-service frequency sharing difficulties are described. Former radio regulations have served adequately for the satellite systems operated from the Geostationary Satellite Orbit (GSO); WARC-92 adopted an interim regulatory system for non-GSO satellite networks. The operation of Low Earth Orbit (LEO) systems are subjected to a number of provisos relating to the protection of planned or existing services; prior to their implementation in LEO, they have to show the possibility of operating within these provisos. A way to resolve difficulties arising from the use of certain frequencies and the approval of terminals are prerequisites for paneuropean operations.

  16. Electromagnetic deep-probing (100-1000 kms) of the Earth's interior from artificial satellites: Constraints on the regional emplacement of crustal resources

    NASA Technical Reports Server (NTRS)

    Hermance, J. F. (Principal Investigator)

    1981-01-01

    Efforts continue in the development of a computer program for looking at the coupling of finite dimensioned source fields with a laterally heterogeneous Earth. An algorithm for calculating a time-varying reference field using ground-based magnetic observatory data is also under development as part of the production of noise-free estimates of global electromagnetic response functions using Magsat data.

  17. Low Earth Orbit satellite traffic simulator

    NASA Technical Reports Server (NTRS)

    Hoelzel, John

    1995-01-01

    This paper describes a significant tool for Low Earth Orbit (LEO) capacity analysis, needed to support marketing, economic, and design analysis, known as a Satellite Traffic Simulator (STS). LEO satellites typically use multiple beams to help achieve the desired communication capacity, but the traffic demand in these beams in usually not uniform. Simulations of dynamic, average, and peak expected demand per beam is a very critical part of the marketing, economic, and design analysis necessary to field a viable LEO system. An STS is described in this paper which can simulate voice, data and FAX traffic carried by LEO satellite beams and Earth Station Gateways. It is applicable world-wide for any LEO satellite constellations operating over any regions. For aeronautical applications to LEO satellites. the anticipates aeronautical traffic (Erlangs for each hour of the day to be simulated) is prepared for geographically defined 'area targets' (each major operational region for the respective aircraft), and used as input to the STS. The STS was designed by Constellations Communications Inc. (CCI) and E-Systems for usage in Brazil in accordance with an ESCA/INPE Statement Of Work, and developed by Analytical Graphics Inc. (AGI) to execute on top of its Satellite Tool Kit (STK) commercial software. The STS simulates constellations of LEO satellite orbits, with input of traffic intensity (Erlangs) for each hour of the day generated from area targets (such as Brazilian States). accumulated in custom LEO satellite beams, and then accumulated in Earth Station Gateways. The STS is a very general simulator which can accommodate: many forms of orbital element and Walker Constellation input; simple beams or any user defined custom beams; and any location of Gateways. The paper describes some of these features, including Manual Mode dynamic graphical display of communication links, to illustrate which Gateway links are accessible and which links are not, at each 'step' of the

  18. On the tidal effects in the motion of earth satellites and the love parameters of the earth

    NASA Technical Reports Server (NTRS)

    Musen, P.; Estes, R.

    1972-01-01

    The tidal effects in the motion of artificial satellites are studied to determine the elastic properties of the earth as they are observed from extraterrestrial space. Considering Love numbers, the disturbing potential is obtained as the analytical continuation of the tidal potential from the surface of the earth into-outer space, with parameters which characterize the earth's elastic response to tidal attraction by the moon and the sun. It is concluded that the tidal effects represent a superposition of a large number of periodic terms, and the rotation of the lunar orbital plane produces a term of 18 years period in tidal perturbations of the ascending node of the satellite's orbit.

  19. On the Tesseral-Harmonics Resonance Problem in Artificial-Satellite Theory, Part 2

    NASA Technical Reports Server (NTRS)

    Romanowicz, B. A.

    1976-01-01

    Equations were derived for the perturbations on an artificial satellite when the motion of the satellite is commensurable with that of the earth. This was done by first selecting the tesseral harmonics that contribute the most to the perturbations and then by applying Hori's method by use of Lie series. Here, are introduced some modifications to the perturbations, which now result in better agreement with numerical integration.

  20. Earth rotation parameters from satellite techniques

    NASA Astrophysics Data System (ADS)

    Thaller, Daniela; Beutler, Gerhard; Jäggi, Adrian; Meindl, Michael; Dach, Rolf; Sosnica, Krzysztof; Baumann, Christian

    2013-04-01

    It has been demonstrated since several years that satellite techniques are capable of determining Earth Rotation Parameters (ERPs) with a daily or even sub-daily resolution. Especially Global Navigation Satellite Systems (GNSS) with their huge amount of observations can determine time series of polar motion (PM) and length of day (LOD) rather well. But also SLR with its spherical satellites whose orbital motions are easy to model and that allow long orbital arc lengths can deliver valuable contributions to Earth rotation. We analyze GNSS solutions (using GPS and GLONASS) and SLR solutions (using LAGEOS) regarding their potential of estimating polar motion and LOD with daily and subdaily temporal resolution. A steadily improving modeling applied in the analysis of space-geodetic data aims at improved time series of geodetic parameters, e.g., the ERPs. The Earth's gravity field and especially its temporal variations are one point of interest for an improved modeling for satellite techniques. For modeling the short-periodic gravity field variations induced by mass variations in the atmosphere and the oceans the GRACE science team provides the Atmosphere and Ocean Dealiasing (AOD) products. They contain 6-hourly gravity fields of the atmosphere and the oceans. We apply these corrections in the analysis of satellite-geodetic data and show the impact on the estimated ERPs. It is well known that the degree-2 coefficients of the Earth's gravity field are correlated with polar motion and LOD. We show to what extent temporal variations in the degree-2 coefficients are influencing the ERP estimates.

  1. Earth observing satellite: Understanding the Earth as a system

    NASA Technical Reports Server (NTRS)

    Soffen, Gerald

    1990-01-01

    There is now a plan for global studies which include two very large efforts. One is the International Geosphere/Biosphere Program (IGBP) sponsored by the International Council of Scientific Unions. The other initiative is Mission to Planet Earth, an unbrella program for doing three kinds of space missions. The major one is the Earth Observation Satellite (EOS). EOS is large polar orbiting satellites with heavy payloads. Two will be placed in orbit by NASA, one by the Japanese and one or two by ESA. The overall mission measurement objectives of EOS are summarized: (1) the global distribution of energy input to and energy output from the Earth; (2) the structure, state variables, composition, and dynamics of the atmosphere from the ground to the mesopause; (3) the physical and biological structure, state, composition, and dynamics of the land surface, including terrestrial and inland water ecosystems; (4) the rates, important sources and sinks, and key components and processes of the Earth's biogeochemical cycles; (5) the circulation, surface temperature, wind stress, sea state, and the biological activity of the oceans; (6) the extent, type, state, elevation, roughness, and dynamics of glaciers, ice sheets, snow and sea ice, and the liquid equivalent of snow in the global cryosphere; (7) the global rates, amounts, and distribution of precipitation; and (8) the dynamic motions of the Earth (geophysics) as a whole, including both rotational dynamics and the kinematic motions of the tectonic plates.

  2. Satellite-tracking and earth-dynamics research programs

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The activities and progress in the satellite tracking and earth dynamics research during the first half of calendar year 1975 are described. Satellite tracking network operations, satellite geodesy and geophysics programs, GEOS 3 project support, and atmospheric research are covered.

  3. Satellite tracking and earth dynamics research programs

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The SAO laser site in Arequipa continued routine operations throughout the reporting period except for the months of March and April when upgrading was underway. The laser in Orroral Valley was operational through March. Together with the cooperating stations in Wettzell, Grasse, Kootwikj, San Fernando, Helwan, and Metsahove the laser stations obtained a total of 37,099 quick-look observations on 978 passes of BE-C, Starlette, and LAGEOS. The Network continued to track LAGEOS at highest priority for polar motion and Earth rotation studies, and for other geophysical investigations, including crustal dynamics, Earth and ocean tides, and the general development of precision orbit determination. The Network performed regular tracking of BE-C and Starlette for refined determinations of station coordinate and the Earth's gravity field and for studies of solid earth dynamics. Monthly statistics of the passes and points are given by station and by satellite.

  4. The Nimbus satellites - Pioneering earth observers

    SciTech Connect

    White, C. )

    1990-11-01

    The many scientific achievements of the Nimbus series of seven satellites for low-altitude atmospheric research and global weather surveillance are reviewed. The series provides information on fishery resources, weather modeling, atmospheric pollution monitoring, earth's radiation budget, ozone monitoring, ocean dynamics, and the effects of cloudiness. Data produced by the forty-eight instruments and sensors flown on the satellites are applied in the fields of oceanography, hydrology, geology, geomorphology, geography, cartography, agriculture and meteorology. The instruments include the Coastal Zone Color Scanner (which depicts phytoplankton concentrations in coastal areas), the Scanning Multichannel Microwave Radiometer (which measures sea-surface temperatures and sea-surface wind-speed), and the Total Ozone Mapping Spectrometer (which provides information on total amounts of ozone in the earth's atmosphere).

  5. The Nimbus satellites - Pioneering earth observers

    NASA Technical Reports Server (NTRS)

    White, Carolynne

    1990-01-01

    The many scientific achievements of the Nimbus series of seven satellites for low-altitude atmospheric research and global weather surveillance are reviewed. The series provides information on fishery resources, weather modeling, atmospheric pollution monitoring, earth's radiation budget, ozone monitoring, ocean dynamics, and the effects of cloudiness. Data produced by the forty-eight instruments and sensors flown on the satellites are applied in the fields of oceanography, hydrology, geology, geomorphology, geography, cartography, agriculture and meteorology. The instruments include the Coastal Zone Color Scanner (which depicts phytoplankton concentrations in coastal areas), the Scanning Multichannel Microwave Radiometer (which measures sea-surface temperatures and sea-surface wind-speed), and the Total Ozone Mapping Spectrometer (which provides information on total amounts of ozone in the earth's atmosphere).

  6. Satellite probes plasma processes in earth orbit

    NASA Technical Reports Server (NTRS)

    Christensen, Andrew B.; Reasoner, David L.

    1992-01-01

    The mission of the DOD/NASA Combined Release and Radiation Effects Satellite (CRRES) is to deepen understanding of the earth's near-space environment, including the radiation belts and the ionosphere; this will help spacecraft designers protect against radiation-belt particles that affect onboard electronics, solar panel arrays, and crewmembers. Attention is presently given to CRRES's study of ionospheric plasma processes through releases of Ba, Ca, Sr, and Li at altitudes of 400-36,000 km.

  7. Scheduling Earth Observing Satellites with Evolutionary Algorithms

    NASA Technical Reports Server (NTRS)

    Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

    2003-01-01

    We hypothesize that evolutionary algorithms can effectively schedule coordinated fleets of Earth observing satellites. The constraints are complex and the bottlenecks are not well understood, a condition where evolutionary algorithms are often effective. This is, in part, because evolutionary algorithms require only that one can represent solutions, modify solutions, and evaluate solution fitness. To test the hypothesis we have developed a representative set of problems, produced optimization software (in Java) to solve them, and run experiments comparing techniques. This paper presents initial results of a comparison of several evolutionary and other optimization techniques; namely the genetic algorithm, simulated annealing, squeaky wheel optimization, and stochastic hill climbing. We also compare separate satellite vs. integrated scheduling of a two satellite constellation. While the results are not definitive, tests to date suggest that simulated annealing is the best search technique and integrated scheduling is superior.

  8. Studying the earth's poles from satellites

    NASA Technical Reports Server (NTRS)

    Thomas, Robert H.

    1991-01-01

    The use of satellite remote sensing is reviewed with respect to the investigation of polar regions and global meteorological processes. Data collected from previous and ongoing satellite missions sponsored by NASA and NOAA are discussed in terms of their ability to describe surface characteristics. Data relating to ocean/atmosphere heat transfer are obtained from microwave radiometers and synthetic aperture radars to give estimates of surface temperatures. Ocean color at several frequencies can be measured to estimate chlorophyll content, and optical and infrared sensors aid in the detection of short- and long-term variance in solar irradiance and earth radiation flux. The geophysical variables collected from satellite data at high latitudes can be used to understand the global climate, atmospheric warming, and other significant mechanisms.

  9. Numerical orbit generators of artificial earth satellites

    NASA Astrophysics Data System (ADS)

    Kugar, H. K.; Dasilva, W. C. C.

    1984-04-01

    A numerical orbit integrator containing updatings and improvements relative to the previous ones that are being utilized by the Departmento de Mecanica Espacial e Controle (DMC), of INPE, besides incorporating newer modellings resulting from the skill acquired along the time is presented. Flexibility and modularity were taken into account in order to allow future extensions and modifications. Characteristics of numerical accuracy, processing quickness, memory saving as well as utilization aspects were also considered. User's handbook, whole program listing and qualitative analysis of accuracy, processing time and orbit perturbation effects were included as well.

  10. On the tesseral-harmonics resonance problem in artificial-satellite theory

    NASA Technical Reports Server (NTRS)

    Romanowicz, B. A.

    1975-01-01

    The longitude-dependent part of the geopotential usually gives rise only to short-period effects in the motion of an artificial satellite. However, when the motion of the satellite is commensurable with that of the earth, the path of the satellite repeats itself relative to the earth and perturbations build up at each passage of the satellite in the same spot, so that there can be important long-period effects. In order to take these effects into account in deriving a theoretical solution to the equations of motion of an artificial satellite, it is necessary to select terms in the longitude-dependent part of the geopotential that will contribute significantly to the perturbations. Attempts made to obtain a selection that is valid in a general case, regardless of the initial eccentricity of the orbit and of the order of the resonance, are reported. The solution to the equations of motion of an artificial satellite, in a geopotential thus determined, is then derived by using Hori's method by Lie series, which, by its properties regarding canonical invariance, has proved advantageous in the classical theory.

  11. SERIES - Satellite Emission Range Inferred Earth Surveying

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.; Spitzmesser, D. J.; Buennagel, L. A.

    1983-01-01

    The Satellite Emission Range Inferred Earth Surveying (SERIES) concept is based on the utilization of NAVSTAR Global Positioning System (GPS) radio transmissions without any satellite modifications and in a totally passive mode. The SERIES stations are equipped with lightweight 1.5 m diameter dish antennas mounted on trailers. A series baseline measurement accuracy demonstration is considered, taking into account a 100 meter baseline estimation from approximately one hour of differential Doppler data. It is planned to conduct the next phase of experiments on a 150 m baseline. Attention is given to details regarding future baseline measurement accuracy demonstrations, aspects of ionospheric calibration in connection with subdecimeter baseline accuracy requirements of geodesy, and advantages related to the use of the differential Doppler or pseudoranging mode.

  12. Removing shadows from Google Earth satellite images

    NASA Astrophysics Data System (ADS)

    Guo, Jianhong; Gong, Peng; Liang, Lu

    2007-06-01

    June 2005, Google has released its geographic search tool "Google earth", a new application that combines local search with satellite images and maps from around the globe. It is designed to make every person owned a computer easily "fly" to aerial views of many locations on the planet. However, just as ordinary satellite images, there inevitably exist shadows in it, made some ground objects obscure, even unidentifiable. According to the basic thinking of Radiative Transfer Theory, this paper built a image shadow removal model, which using the Radiative Transfer Theory combined with preknowledge to compensate the lost shadow area information. The results shows: shadows in images were successfully removed and the target objects were returned to their original scenes.

  13. Earth Observatory Satellite (EOS) system definition study

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An executive summary of a study on the Earth Observatory Satellite (EOS) was presented. It was concluded that the overall costs of space systems could be reduced significantly by the development of a modular shuttle compatible standard spacecraft, and the use of that spacecraft with the Shuttle Transportation System. It was also demonstrated that the development of the standard spacecraft is feasible, desirable, and cost effective if applied to a series of missions. The ability to initially retrieve, refurbish, and reuse the spacecraft and its payload, and ultimately to perform in-orbit servicing, would result in significant cost savings. A number of specific conclusions and recommendations were also suggested.

  14. Earth Satellite Population Instability: Underscoring the Need for Debris Mitigation

    NASA Technical Reports Server (NTRS)

    Liou, Jer-chyi; Johnson, N. L.

    2006-01-01

    A recent study by NASA indicates that the implementation of international orbital debris mitigation measures alone will not prevent a significant increase in the artificial Earth satellite population, beginning in the second half of this century. Whereas the focus of the aerospace community for the past 25 years has been on the curtailment of the generation of long-lived orbital debris, active remediation of the current orbital debris population should now be reconsidered to help preserve near-Earth space for future generations. In particular, we show in this paper that even if launch operations were to cease today, the population of space debris would continue to grow. Further, proposed remediation techniques do not appear to offer a viable solution. We therefore recommend that, while the aerospace community maintains the current debris-limiting mission regulations and postmission disposal procedures, future emphasis should be placed on finding new remediation technologies for solving this growing problem. Since the launch of Sputnik 1, space activities have created an orbital debris environment that poses increasing impact risks to existing space systems, including human space flight and robotic missions (1, 2). Currently, more than 9,000 Earth orbiting man-made objects (including many breakup fragments), with a combined mass exceeding 5 million kilograms, are tracked by the US Space Surveillance Network and maintained in the US satellite catalog (3-5). Three accidental collisions between cataloged satellites during the period from late 1991 to early 2005 have already been documented (6), although fortunately none resulted in the creation of large, trackable debris clouds. Several studies conducted during 1991-2001 demonstrated, with assumed future launch rates, the unintended growth potential of the Earth satellite population, resulting from random, accidental collisions among resident space objects (7-13). In some low Earth orbit (LEO) altitude regimes where

  15. Polarization Tracking Study of Earth Station in Satellite Communications

    NASA Astrophysics Data System (ADS)

    Ma, Lihua; Hu, Chao; Pei, Jun

    2016-01-01

    Satellite communications, in telecommunications, the use of satellite can provide communications links between various points on the earth. Typical satellite communication is composed of a communication satellite, a signal transmitter and a signal receiver. As the signal transmitter or the signal receiver, an earth station plays a vital role in the satellite communications. Accurately adjustment of antenna azimuth, elevation and polarization angles on the earth station is the key to satellite communications. In the present paper, a study of polarization tracking of earth station is presented, and a detailed adjustment procession of the polarization angle is given. Combing with observation series of MEASAT-2 satellite in geostationary orbit, the polarization tracking accuracy is verified. The method can be embeded into computer program of antenna polarization adjustment in earth station.

  16. Earth satellites: A first look by the United States Navy

    NASA Technical Reports Server (NTRS)

    Hall, R. C.

    1977-01-01

    Immediately following World War II, the U.S. Navy considered the possibility of launching an earth satellite for navigational, communications, and meteorological applications. The technical feasibility of the satellite was based on extensions of German V-2 technology.

  17. Earth Observing Satellite Orbit Design Via Particle Swarm Optimization

    DTIC Science & Technology

    2014-08-01

    Earth Observing Satellite Orbit Design Via Particle Swarm Optimization Sharon Vtipil ∗ and John G. Warner ∗ US Naval Research Laboratory, Washington...DC, 20375, United States Designing the orbit of an Earth observing satellite is generally tedious work. Typically, a large number of numerical...orbit parameters. This methodology only pertains to a single satellite in a circular orbit. I. Introduction Designing the orbit of an Earth observing

  18. Uniaxial aerodynamic attitude control of artificial satellites

    NASA Technical Reports Server (NTRS)

    Sazonov, V. V.

    1983-01-01

    Within the context of a simple mechanical model the paper examines the movement of a satellite with respect to the center of masses under conditions of uniaxial aerodynamic attitude control. The equations of motion of the satellite take account of the gravitational and restorative aerodynamic moments. It is presumed that the aerodynamic moment is much larger than the gravitational, and the motion equations contain a large parameter. A two-parameter integrated surface of these equations is constructed in the form of formal series in terms of negative powers of the large parameter, describing the oscillations and rotations of the satellite about its lengthwise axis, approximately oriented along the orbital tangent. It is proposed to treat such movements as nominal undisturbed motions of the satellite under conditions of aerodynamic attitude control. A numerical investigation is made for the above integrated surface.

  19. Earth Observatory Satellite (EOS) Definition Phase Report, Volume 1

    NASA Technical Reports Server (NTRS)

    1971-01-01

    System definition studies were conducted of the Earth Observatory Satellite (EOS). The studies show that the concept of an Earth Observatory Satellite in a near-earth, sun-synchronous orbit would make a unique contribution to the goals of a coordinated program for acquisition of data for environmental research with applications to earth resource inventory and management. The technical details for the proposed development of sensors, spacecraft, and a ground data processing system are presented.

  20. The Population of Natural Earth Satellites

    NASA Astrophysics Data System (ADS)

    Granvik, Mikael; Vaubaillon, J.; Jedicke, R.

    2010-10-01

    We present the first debiased size-frequency and orbit distributions for a steady-state population of temporary-captured, natural Earth satellites (NES) excluding the Moon. We use orbital integrations to estimate the capture probability as a function of orbital elements and utilize the steady-state near-Earth-object (NEO) model by Bottke et al. (2002) to estimate the steady-state population of NESs. For much of the 20th century NESs other than the Moon were not discussed in their own right but mentioned in the published literature only as a population producing meteors that travel far in the Earth's atmosphere or as a population explaining shallow meteorite impacts. Only during the last two decades has a couple of these objects been detected in space; 1991 VG and 2006 RH120. The origin and evolution of 1991 VG, e.g., whether it is a man-made or a natural object, can be debated, but 2006 RH120 is certainly natural with an absolute magnitude H of about 29.9. To gain understanding of this little studied and barely detected population's origin and evolution, we try to answer questions such as: At any instant, how many objects are in temporary capture as a function of their size? What are the characteristics of their pre- capture geocentric trajectories and heliocentric orbits? What is the typical duration of the temporary capture? How many orbits do NESs typically complete around the Earth? What are the characteristics of their geocentric orbits? We anticipate that the interest in this small and nearby population will increase in the future as NESs are easily accessible targets for proposed NEO sample-return missions. Their typically small sizes could allow us to bring back an entire asteroid with the benefit that, e.g., microscopic surface or near-surface effects such as space weathering and lightscattering could be studied on a pristine body in ground-based laboratories.

  1. Satellite-tracking and Earth dynamics research programs

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Tracking of LAGEOS for polar motion and Earth rotation studies and for other geophysical investigations, including crustal dynamics, Earth and ocean tides, and the general development of precision orbit determination continues. The BE-C and Starlette satellites were tracked for refined determinations of station coordinates and the Earth's gravity field and for studies of solid Earth dynamics.

  2. Meteorological factors in Earth-Satellite propagation

    NASA Technical Reports Server (NTRS)

    Levis, C. A.; Damon, E. K.; Lin, K. T.; Weller, A. E., III

    1984-01-01

    A 5-meter paraboloidal antenna operated at 28 GHz showed gain changes of 2 dB due to rain. While precise estimation of the corresponding angle of arrival changes is difficult, they appear to have been on the order of 0.02 degrees. The attenuation at 28.6 GHz inferred from radiometry agreed well with that measured simultaneously over a satellite/Earth link at the same frequency. The radiometers so calibrated have been used to add to the available site diversity data base using a 9 km baseline. An improved empirical model of site diversity gain was obtained by applying regression techniques to available published data. A brief review of the literature has led to suggestions for two experimental programs, one dealing with multifrequency radiometry and the other with the effects of the stochastic properties of precipitation on wideband data transmission.

  3. Operational evapotranspiration based on Earth observation satellites

    NASA Astrophysics Data System (ADS)

    Gellens-Meulenberghs, Françoise; Ghilain, Nicolas; Arboleda, Alirio; Barrios, Jose-Miguel

    2016-04-01

    Geostationary satellites have the potential to follow fast evolving atmospheric and Earth surface phenomena such those related to cloud cover evolution and diurnal cycle. Since about 15 years, EUMETSAT has set up a network named 'Satellite Application Facility' (SAF, http://www.eumetsat.int/website/home/Satellites/GroundSegment/Safs/index.html) to complement its ground segment. The Land Surface Analysis (LSA) SAF (http://landsaf.meteo.pt/) is devoted to the development of operational products derived from the European meteorological satellites. In particular, an evapotranspiration (ET) product has been developed by the Royal Meteorological Institute of Belgium. Instantaneous and daily integrated results are produced in near real time and are freely available respectively since the end of 2009 and 2010. The products cover Europe, Africa and the Eastern part of South America with the spatial resolution of the SEVIRI sensor on-board Meteosat Second Generation (MSG) satellites. The ET product algorithm (Ghilain et al., 2011) is based on a simplified Soil-Vegetation-Atmosphere transfer (SVAT) scheme, forced with MSG derived radiative products (LSA SAF short and longwave surface fluxes, albedo). It has been extensively validated against in-situ validation data, mainly FLUXNET observations, demonstrating its good performances except in some arid or semi-arid areas. Research has then been pursued to develop an improved version for those areas. Solutions have been found in reviewing some of the model parameterizations and in assimilating additional satellite products (mainly vegetation indices and land surface temperature) into the model. The ET products will be complemented with related latent and sensible heat fluxes, to allow the monitoring of land surface energy partitioning. The new algorithm version should be tested in the LSA-SAF operational computer system in 2016 and results should become accessible to beta-users/regular users by the end of 2016/early 2017. In

  4. Interferometric observations of an artificial satellite.

    PubMed

    Preston, R A; Ergas, R; Hinteregger, H F; Knight, C A; Robertson, D S; Shapiro, I I; Whitney, A R; Rogers, A E; Clark, T A

    1972-10-27

    Very-long-baseline interferometric observations of radio signals from the TACSAT synchronous satellite, even though extending over only 7 hours, have enabled an excellent orbit to be deduced. Precision in differenced delay and delay-rate measurements reached 0.15 nanosecond ( approximately 5 centimeters in equivalent differenced distance) and 0.05 picosecond per second ( approximately 0.002 centimeter per second in equivalent differenced velocity), respectively. The results from this initial three-station experiment demonstrate the feasibility of using the method for accurate satellite tracking and for geodesy. Comparisons are made with other techniques.

  5. Naval EarthMap Observer (NEMO) satellite

    NASA Astrophysics Data System (ADS)

    Wilson, Thomas L.; Davis, Curtiss O.

    1999-10-01

    The Office of Naval Research (ONR) and the Naval Research Laboratory (NRL) have initiated the Hyperspectral Remote Sensing Technology (HRST) program to demonstrate the utility of a hyperspectral earth-imaging system to support Naval needs for characterization of the littoral regions of the world. One key component of the HRST program is the development of the Naval EarthMap Observer (NEMO) satellite system to provide a large hyperspectral data base. NEMO will carry the Coastal Ocean Imaging Spectrometer (COIS) which will provide images of littoral regions with 210 spectral channels over a bandpass of 0.4 to 2.5 micrometer. Since ocean environments have reflectances typically less than 5%, this system requires a very high signal-to-noise ratio (SNR). COIS will sample over a 30 km swath width with a 60 m Ground Sample Distance (GSD) with the ability to go to a 30 m GSD by utilizing the systems attitude control system to 'nod' (i.e., use ground motion compensation to slow down the ground track of the field of view). Also included in the payload is a co-registered 5 m Panchromatic Imager (PIC) to provide simultaneous high spatial resolution imagery. A sun-synchronous, 97.81 degree inclination, circular orbit of 605 km allows continuous repeat coverage of the whole earth. One unique aspect of NEMO is an on-board processing system, a feature extraction and data compression software package developed by NRL called the Optical Real-Time Spectral Identification System (ORASIS). ORASIS employs a parallel, adaptive hyperspectral method for real time scene characterization, data reduction, background suppression, and target recognition. The use of ORASIS is essential for management of the massive amounts of data expected from the NEMO HSI system, and for developing Naval products under HRST. The combined HSI and panchromatic images will provide critical phenomenology to aid in the operation of Naval systems in the littoral environment. The imagery can also satisfy a number of

  6. On the tidal effects in the motion of artificial satellites.

    NASA Technical Reports Server (NTRS)

    Musen, P.; Estes, R.

    1972-01-01

    The general perturbations in the elliptic and vectorial elements of a satellite as caused by the tidal deformations of the non-spherical Earth are developed into trigonometric series in the standard ecliptical arguments of Hill-Brown lunar theory and in the equatorial elements of the satellite. The integration of the differential equations for variation of elements of the satellite in this theory is easy because all arguments are linear or nearly linear in time. The trigonometrical expansion permits a judgment about the relative significance of the amplitudes and periods of different tidal 'waves' over a long period of time. Graphs are presented of the tidal perturbations in the elliptic elements of the BE-C satellite which illustrate long term periodic behavior. The tidal effects are clearly noticeable in the observations and their comparison with the theory permits improvement of the 'global' Love numbers for the Earth.

  7. Radio detection of thunderstorm activity with an earth-orbiting satellite

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Stone, R. G.; Caruso, J. A.

    1975-01-01

    A study was made to determine the feasibility of using artificial earth satellites to monitor thunderstorm activity. The nighttime noise-temperature measurements made with the earth-oriented vee antenna of the Radio Astronomy Explorer (RAE 1) satellite in the frequency range 0.2-9.2 MHz were correlated with reported surface thunderstorm activity. Analysis shows that the minimum nighttime HF noise level (in the absence of surface thunderstorms) at an altitude of 5850 km over the United States is fixed by man-made noise. When thunderstorms are active below the satellite, the noise level is increased by about 6-12 dB. The highest level is associated with the most intense storms. It is concluded that thunderstorm regions can be detected by an orbiting satellite using HF radio techniques, but ionospheric effects must be taken into account.

  8. Looking at Earth from space: Direct readout from environmental satellites

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Direct readout is the capability to acquire information directly from meteorological satellites. Data can be acquired from NASA-developed, National Oceanic and Atmospheric Administration (NOAA)-operated satellites, as well as from other nations' meteorological satellites. By setting up a personal computer-based ground (Earth) station to receive satellite signals, direct readout may be obtained. The electronic satellite signals are displayed as images on the computer screen. The images can display gradients of the Earth's topography and temperature, cloud formations, the flow and direction of winds and water currents, the formation of hurricanes, the occurrence of an eclipse, and a view of Earth's geography. Both visible and infrared images can be obtained. This booklet introduces the satellite systems, ground station configuration, and computer requirements involved in direct readout. Also included are lists of associated resources and vendors.

  9. NASA Now: Orbital Mechanics: Earth Observing Satellites

    NASA Video Gallery

    This NASA Now program is all about satellites and their orbits. Dr. James Gleason, project scientist for NPP, explains what it takes for a satellite to stay in orbit, why there are different types ...

  10. Sampling analysis for the earth radiation budget satellite system mission

    NASA Technical Reports Server (NTRS)

    Harrison, E. F.; Gibson, G. G.

    1977-01-01

    A study was conducted to identify problems related to sampling the Earth's radiant energy budget and to define a satellite system with sufficient sampling to satisfy science requirements on global, zonal, and regional scales.

  11. Low Earth Orbit satellite/terrestrial mobile service compatibility

    NASA Technical Reports Server (NTRS)

    Sheriff, Ray E.; Gardiner, John G.

    1993-01-01

    Currently the geostationary type of satellite is the only one used to provide commercial mobile-satellite communication services. Low earth orbit (LEO) satellite systems are now being proposed as a future alternative. By the implementation of LEO satellite systems, predicted at between 5 and 8 years time, mobile space/terrestrial technology will have progressed to the third generation stage of development. This paper considers the system issues that will need to be addressed when developing a dual mode terminal, enabling access to both terrestrial and LEO satellite systems.

  12. GPS early-orbit subsystem for earth satellites

    NASA Technical Reports Server (NTRS)

    Laczo, V. T.; Maury, J. L.

    1972-01-01

    The early-orbit capability of the Goddard Trajectory Determination System, which determines starting vectors for earth satellites from angles-only or range-angles observations, is described and documented. Early-orbit results obtained from a variety of satellites, data types and methods of solution are also presented.

  13. Algorithms and programs complex for solving inverse problems of artificial Earth satellite dynamics with using parallel computation. (Russian Title: Программно-математическое обеспечение для решения обратных задач динамики ИСЗ с использованием параллельных вычислений )

    NASA Astrophysics Data System (ADS)

    Chuvashov, I. N.

    2011-07-01

    In this paper complex of algorithms and programs for solving inverse problems of artificial earth satellite dynamics is described. Complex has been intended for satellite orbit improvement, calculation of motion model parameters and etc. Programs complex has been worked up for cluster "Skiff Cyberia". Results of numerical experiments obtained by using new complex in common the program "Numerical model of the system artificial satellites motion" is presented in this paper.

  14. Satellite measurements of the earth's crustal magnetic field

    NASA Technical Reports Server (NTRS)

    Schnetzler, C. C.

    1989-01-01

    The literature associated with the Magsat mission has evaluated the capabilities and limitations of satellite measurements of the earth's crustal magnetic field, and demonstrated that there exists a 300-3000 km magnetic field, related to major features in the earth's crust, which is primarily caused by induction. Due to its scale and sensitivity, satellite data have been useful in the development of models for such large crustal features as subduction zones, submarine platforms, continental accretion boundaries, and rifts. Attention is presently given to the lack of agreement between laboratory and satellite estimates of lower crustal magnetization.

  15. Activities and future plan of earth observation by satellites

    NASA Astrophysics Data System (ADS)

    Hakura, Yukio

    1980-09-01

    The Earth Observation Center of NASDA has been receiving MSS (multispectral scanner) and RBV (return beam vidicon) data from NASAs Landsat satellites since January 1979. The data are widely used for research and applications by government institutions, universities, industries, etc. The first of Japanese Earth observation satellite series, MOS-1 (Marine Observation Satellite-1) which carries MESSR (visible and near-IR radiometer of push-broom scanning type), VTIR (visible and thermal IR radiometer), and MSR (microwave scanning radiometer), is under development with target date of its launch in 1984 FY.

  16. The effects of general relativity on near-earth satellites

    NASA Technical Reports Server (NTRS)

    Ries, J. C.; Watkins, M. M.; Tapley, B. D.; Huang, C.

    1990-01-01

    Whether one uses a solar system barycentric frame or a geocentric frame when including the general theory of relativity in orbit determination for near-earth satellites, the results should be equivalent to some limiting accuracy. The purpose of this paper is to clarify the effects of relativity in each frame and to demonstrate their equivalence through the analysis of three years of laser tracking data taken on the Lageos satellite. It is demonstrated that the simpler formulation in the geocentric frame is adequate for the purpose of near-earth satellite orbit determination. A correction to the conventional barycentric equations of motion is shown to be required.

  17. Asteroid 2014 OL339: yet another Earth quasi-satellite

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2014-12-01

    Our planet has one permanently bound satellite - the Moon - a likely large number of mini-moons or transient irregular natural satellites, and three temporary natural retrograde satellites or quasi-satellites. These quasi-moons - (164207) 2004 GU9, (277810) 2006 FV35 and 2013 LX28 - are unbound companions to the Earth. The orbital evolution of quasi-satellites may transform them into temporarily bound satellites of our planet. Here, we study the dynamical evolution of the recently discovered Aten asteroid 2014 OL339 to show that it is currently following a quasi-satellite orbit with respect to the Earth. This episode started at least about 775 yr ago and it will end 165 yr from now. The orbit of this object is quite chaotic and together with 164207 are the most unstable of the known Earth quasi-satellites. This group of minor bodies is, dynamically speaking, very heterogeneous but three of them exhibit Kozai-like dynamics: the argument of perihelion of 164207 oscillates around -90°, the one of 277810 librates around 180° and that of 2013 LX28 remains around 0°. Asteroid 2014 OL339 is not currently engaged in any Kozai-like dynamics.

  18. CEOS Committee on Earth Observations Satellites Consolidated Report, 1992

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A concise overview of the committee on Earth Observations Satellites (CEOS) and its Working Groups, covering the history and purpose of the Committee and its accomplishments to date are provided. The report will be updated annually before each Plenary meeting, and as developments in the Working Groups warrant. The committee on Earth Observations Satellites (originally named the International Earth Observations Satellite committee, IEOS) was treated in 1984, in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. This group recognized the multidisciplinary nature of satellite Earth observations, and the value of coordinating across all proposed missions. Thus, CEOS combined the previously existing groups for coordination on Ocean Remote-Sensing Satellites (CORSS) and coordination on Land Remote-Sensing Satellites (CLRSS), and established a broad framework for coordination across all spaceborne Earth observations missions. The first three LEOS Plenary meetings focused on treating and guiding the Working Groups deemed necessary to carry out the objectives of the CEOS members. After the third meeting, it was agreed that a more active orientation was required by the Plenary, and additional issues were brought before the group at the fourth meeting. At the fifth Plenary, international scientific programs and relevant intergovernmental organizations accepted invitations and participated as affiliate members of CEOS. This enabled progress toward integrating satellite data users' requirements into the CEOS process. Data exchange principles for global change research were also adopted. An interim CEOS Plenary meeting was held in April 1992, in preparation for the United Nations Conference on Environment and Development (UNCED). Brief encapsulations of the Plenary sessions immediately follow the Terms of Reference that govern the activities of CEOS as

  19. Monitoring objects orbiting earth using satellite-based telescopes

    DOEpatents

    Olivier, Scot S.; Pertica, Alexander J.; Riot, Vincent J.; De Vries, Willem H.; Bauman, Brian J.; Nikolaev, Sergei; Henderson, John R.; Phillion, Donald W.

    2015-06-30

    An ephemeris refinement system includes satellites with imaging devices in earth orbit to make observations of space-based objects ("target objects") and a ground-based controller that controls the scheduling of the satellites to make the observations of the target objects and refines orbital models of the target objects. The ground-based controller determines when the target objects of interest will be near enough to a satellite for that satellite to collect an image of the target object based on an initial orbital model for the target objects. The ground-based controller directs the schedules to be uploaded to the satellites, and the satellites make observations as scheduled and download the observations to the ground-based controller. The ground-based controller then refines the initial orbital models of the target objects based on the locations of the target objects that are derived from the observations.

  20. Precise Orbit Determination of Low Earth Satellites at AIUB

    NASA Astrophysics Data System (ADS)

    Jaggi, A.; Bock, H.; Thaller, D.; Dach, R.; Beutler, G.; Prange, L.; Meyer, U.

    2010-12-01

    Many low Earth orbiting (LEO) satellites are nowadays equipped with on-board receivers to collect the observations from Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), or with retro-reflectors for Satellite Laser Ranging (SLR). At the Astronomical Institute of the University of Bern (AIUB) LEO precise orbit determination (POD) using either GPS or SLR data is performed for satellites at very different altitudes. The classical numerical integration techniques used for dynamic orbit determination of LEO satellites at high altitudes are extended by pseudo-stochastic orbit modeling techniques for satellites at low altitudes to efficiently cope with force model deficiencies. Accuracies of a few centimeters are achieved by pseudo-stochastic orbit modeling, e.g., for the Gravity field and steady-state Ocean Circulation Explorer (GOCE).

  1. System implementation for earth radiation budget satellite system

    NASA Technical Reports Server (NTRS)

    Cooper, J. E.; Woerner, C. V.

    1978-01-01

    The earth-orbiting satellite provides a platform, outside the earth's atmosphere, which is capable of simultaneously monitoring the outgoing reflection of the sun's energy from the earth's surface and atmosphere, and the longwave radiation emitted by the earth and its atmosphere. These capabilities provide the opportunity to conduct detailed studies of the variations in the earth's radiation budget, the effects of natural and manmade changes in the environment on this budget, and the effects which changes in the energy budget produce on earth's weather and climate. A description is presented of the instrument system requirements and a conceptual design of an instrument approach to meet these requirements for providing the earth radiation budget data.

  2. Satellite-tracking and Earth dynamics research programs

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The major focus for operations during this period was the preliminary MERIT Campaign and its intensive tracking of LAGEOS for polar motion and Earth rotation studies. The data acquired from LAGEOS were used for other geophysical investigations, including studies of crustal dynamics, and Earth and ocean tides, and for the general development of precision orbit determination. The network performed regular tracking of several other retroreflector satellites including GEOS-1, GEOS-3, BE-C, and Starlette for refined determinations of station coordinates and Earth's gravity field and for studies of solid Earth dynamics.

  3. A comparison of three classical analytical theories for the motion of artificial satellites

    NASA Technical Reports Server (NTRS)

    Gordon, R. A.; Mistreets, G. D.; Watson, J. S.

    1978-01-01

    Motivated by the heavy reliance upon the analytic orbit theory in orbit determination operations at the Goddard Space Flight Center (GSFC), a comparison study is performed for three classical analytical theories of artificial satellite motion about an oblate earth. The three analytical theories are: (1) Brouwer, (2) a modified Brouwer, i.e., Brouwer-Lyddane and Cohen, and (3) Vinti. Comparison results for each theory are produced for a number of representative satellites of current or past interest which proved amenable to analytic theory application. The uniformity of these results has significant implications for current and future mission operations and planning activities. Subsidiary topics arising from the results of this study which relate to the optimum usage of the individual theories are also discussed

  4. Relativity mission with two counter-orbiting polar satellites. [nodal dragging effect on earth orbiting satellites

    NASA Technical Reports Server (NTRS)

    Van Patten, R. A.; Everitt, C. W. F.

    1975-01-01

    In 1918, J. Lense and H. Thirring calculated that a moon in orbit around a massive rotating planet would experience a nodal dragging effect due to general relativity. We describe an experiment to measure this effect with two counter-orbiting drag-free satellites in polar earth orbit. For a 2 1/2 year experiment, the measurement accuracy should approach 1%. In addition to precision tracking data from existing ground stations, satellite-to-satellite Doppler ranging data are taken at points of passing near the poles. New geophysical information on both earth harmonics and tidal effects is inherent in the polar ranging data.

  5. Documenting Long-term Earth System Evolution With Satellite Observations

    NASA Astrophysics Data System (ADS)

    Kaye, J. A.; Koblinsky, C. J.; Cramer, B.; Karl, T.; Privette, J. L.

    2007-12-01

    Satellite observations play a critical role in documenting earth system evolution, both in terms of characterizing prior and current evolution of the Earth and providing a baseline against which future measurements can be compared. Given that the construction of the necessary long-term data sets requires the use of multiple instruments on multiple platforms, each of which may have their own characteristics, drifts, and degradation, this represents a significant challenge to the scientific community. Over the last 30-or so years, going back to the launch of the Nimbus 7 in 1978, earth scientists learned significant lessons about how to create accurate and stable long-term data records. Sponsoring agencies have tried to capture the lessons and use them as a basis for planning for future systems. This presentation will examine and present future approaches to maximize the quality of the long-term data records produced from earth satellites.

  6. Satellite-tracking and earth-dynamics research programs

    NASA Technical Reports Server (NTRS)

    Weiffenbach, G. C.

    1973-01-01

    The following activities in Smithsonian Astrophysical Observatory's (SAO) earth-dynamics programs are covered: (1) satellite-tracking network operations; (2) satellite geodesy and geophysics programs; (3) atmospheric research. Approximately 46,000 successful range measurements were acquired by the SAO laser stations in Peru, South Africa, Brazil, and Arizona. The Peole satellite-tracking campaign conducted in conjunction with the Centre National d'Etudes Spatiales was completed in August 1973. The SAO network obtained 4482 validated returns of 310 arcs of Peole. These data are of particular value for obtaining more accurate gravity-field and zonal-harmonics coefficients.

  7. Aircraft earth station for experimental mobile satellite system

    NASA Astrophysics Data System (ADS)

    Ohmori, S.; Hase, Y.; Kosaka, K.; Tanaka, M.

    A mobile satellite communication system, which can provide high quality service for small ships and aircraft, has been studied in Japan. This system is scheduled to be carried into experimental and evaluation phase in 1987, when a geostationary satellite (ETS-V) is launched by a Japanese rocket. This paper describes an aircraft earth station, which can establish telephone communication links for passengers on board the aircraft. The new technologies, especially an airborne phased array antenna, are developed. This is the first development in the world in mobile satellite communication areas.

  8. On the development of earth observation satellite systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Subsequent to the launching of the first LANDSAT by NASA, Japan has recognized the importance of data from earth observation satellites, has conducted studies, and is preparing to develop an independent system. The first ocean observation satellite will be launched in 1983, the second in 1985. The first land observation satellite is scheduled to be launched in 1987 and by 1990 Japan intends to have both land and ocean observation systems in regular operation. The association reception and data processing systems are being developed.

  9. A Lower Size Limit for Near-Earth Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Busch, M.; Jacobson, S. A.; Benner, L.; Brozovic, M.; Howell, E. S.; Margot, J.; Naidu, S.; Shepard, M. K.; Taylor, P. A.

    2013-12-01

    Over 40 near-Earth asteroids are now known to have satellites. Delay-Doppler radar imaging has identified the majority of these systems, including both known triple NEAs. Roughly one-sixth of NEAs larger than ~200 m in diameter have satellites; this fraction rises to two-thirds for rapidly rotating large NEAs with spin periods between 2 and 3.5 hours. This distribution is consistent with many NEAs being rubble-pile objects that are disrupted by YORP radiation-pressure spin-up. The observed volume and inferred mass ratios for NEA satellites vary widely, from about 1:1 for the nearly-equal-mass binary 69230 Hermes to 1:1000 or more for objects like 1862 Apollo. The smallest known satellite of any near-Earth asteroid is that of 2004 DC, which has a satellite that is ~60 m in diameter. We have studied archival radar observations to place limits on the occurrence of still smaller satellites. Nearly 60 NEAs with diameters >200 m and spin periods <3.5 hours have been imaged by the Arecibo and Goldstone planetary radars. Again, roughly two-thirds of these objects have satellites 60 m or more in diameter. For 14 objects, we would have been able to detect satellites as small as or smaller than 50 m had they been present, assuming a satellite spin period of >2 hours and setting an SNR threshold of >5/delay-Doppler pixel. For 10 objects, our detection limit was <15 m. For 3 objects, it was <5 m. We do not exclude small satellites entirely, but the fraction of large fast-spinning NEAs with satellites 15 - 50 m in diameter is conservatively <15%, many times less than the fraction with larger satellites. While rotational fission is the probable source of the NEA satellites, the details of satellite formation are not well understood. There are two proposed processes for producing satellites on stable orbits around their primaries. First, the primary may experience several small fission events, and the material in orbit accumulate into a single large satellite. Second, the primary

  10. Advances in Satellite Observations of Earth's Radiation Budget

    NASA Astrophysics Data System (ADS)

    Loeb, N. G.; Kato, S.; Rose, F. G.; Rutan, D. A.

    2013-05-01

    The first observation of Earth's radiation budget from satellite dates back to the beginning of the satellite era in late 1950s, when the first satellite images of the planet were recorded. With each passing decade since then, the science community has made advances in instrument technology that has led to a wealth of new information about the sunlight reaching Earth, Earth's albedo, and the emission of thermal radiation to space. Until recently, however, most of the observational breakthroughs were limited to Earth's top-of-atmosphere (TOA) radiation budget. The recent arrival of instruments flown under the Earth Observing System (EOS) and the A-Train constellation of satellites has dramatically changed this situation, providing new opportunities to synergistically combine an array of diverse passive and active satellite instruments to more accurately determine Earth's surface radiation budget. The new data have led to renewed discussions about our basic understanding of Earth's water and energy cycles. The goal of this presentation is to discuss how the new satellite instrument capabilities are being used by the Clouds and the Earth's Radiant Energy (CERES) science team to provide improved observations of the TOA, surface and within-atmosphere radiation budgets and the role clouds play in modulating the energy flows. We focus on the CERES TOA and surface Energy Balanced and Filled (EBAF) product, which combines information from CERES, MODIS, CALIPSO, Cloudsat, AIRS, and geostationary observations all integrated in a consistent manner, and demonstrate how synergistic use of these datasets leads to improved radiative fluxes when compared with surface radiation measurements from the Baseline Surface Radiation Network (BSRN), NOAA SURFRAD, and ARM. We find that EBAF-SFC reduces the bias in surface SW downward flux by a factor of 2 compared to other satellite-based surface radiation budget datasets, show marked reductions in surface downward longwave radiation biases

  11. Space vehicle with artificial gravity and earth-like environment

    NASA Technical Reports Server (NTRS)

    Gray, V. H. (Inventor)

    1973-01-01

    A space vehicle adapted to provide an artificial gravity and earthlike atmospheric environment for occupants is disclosed. The vehicle comprises a cylindrically shaped, hollow pressure-tight body, one end of which is tapered from the largest diameter of the body, the other end is flat and transparent to sunlight. The vehicle is provided with thrust means which rotates the body about its longitudinal axis, generating an artificial gravity effect upon the interior walls of the body due to centrifugal forces. The walls of the tapered end of the body are maintained at a temperature below the dew point of water vapor in the body and lower than the temperature near the transparent end of the body. The controlled environment and sunlight permits an earth like environment to be maintained wherein the CO2/O2 is balanced, and food for the travelers is supplied through a natural system of plant life grown on spacecraft walls where soil is located.

  12. The Earth Phenomena Observing System: Intelligent Autonomy for Satellite Operations

    NASA Technical Reports Server (NTRS)

    Ricard, Michael; Abramson, Mark; Carter, David; Kolitz, Stephan

    2003-01-01

    Earth monitoring systems of the future may include large numbers of inexpensive small satellites, tasked in a coordinated fashion to observe both long term and transient targets. For best performance, a tool which helps operators optimally assign targets to satellites will be required. We present the design of algorithms developed for real-time optimized autonomous planning of large numbers of small single-sensor Earth observation satellites. The algorithms will reduce requirements on the human operators of such a system of satellites, ensure good utilization of system resources, and provide the capability to dynamically respond to temporal terrestrial phenomena. Our initial real-time system model consists of approximately 100 satellites and large number of points of interest on Earth (e.g., hurricanes, volcanoes, and forest fires) with the objective to maximize the total science value of observations over time. Several options for calculating the science value of observations include the following: 1) total observation time, 2) number of observations, and the 3) quality (a function of e.g., sensor type, range, slant angle) of the observations. An integrated approach using integer programming, optimization and astrodynamics is used to calculate optimized observation and sensor tasking plans.

  13. Microlensing planet detection via geosynchronous and low Earth orbit satellites

    NASA Astrophysics Data System (ADS)

    Mogavero, F.; Beaulieu, J. P.

    2016-01-01

    Planet detection through microlensing is usually limited by a well-known degeneracy in the Einstein timescale tE, which prevents mass and distance of the lens to be univocally determined. It has been shown that a satellite in geosynchronous orbit could provide masses and distances for most standard planetary events (tE ≈ 20 days) via a microlens parallax measurement. This paper extends the analysis to shorter Einstein timescales, tE ≈ 1 day, when dealing with the case of Jupiter-mass lenses. We then study the capabilities of a low Earth orbit satellite on even shorter timescales, tE ≈ 0.1 days. A Fisher matrix analysis is employed to predict how the 1-σ error on parallax depends on tE and the peak magnification of the microlensing event. It is shown that a geosynchronous satellite could detect parallaxes for Jupiter-mass free floaters and discover planetary systems around very low-mass brown dwarfs. Moreover, a low Earth orbit satellite could lead to the discovery of Earth-mass free-floating planets. Limitations to these results can be the strong requirements on the photometry, the effects of blending, and in the case of the low orbit, the Earth's umbra.

  14. In-Orbit Earth Radiation Budget Satellite (ERBS) Battery Switch

    NASA Technical Reports Server (NTRS)

    Ahmad, Anisa; Enciso, Marlon; Rao, Gopalakrishna

    2000-01-01

    A viewgraph presentation outlines the Earth Radiation Budget Satellite (ERBS) power system and battery history. ERBS spacecraft and battery cell failures are listed with the reasons for failure. The battery management decision and stabilization of the batteries is discussed. Present battery operations are shown to be successful.

  15. Verification of KAM Theory on Earth Orbiting Satellites

    DTIC Science & Technology

    2010-03-01

    Appendix B. Earth Orbiting Satellite Hamiltonian Derivation . . . . . . . . . . . . . 41 Appendix C. Non -linear Least Squares Estimation within SGP4...43 C.1 Least Squares Origin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 C.2 Non -Linear Least Squares...Naturalis Principia Mathe- matica in 1687 up until the late eighteenth century, Newtonian Mechanics was mechan- ics [9]. With F = ma, forces on single

  16. Sensor Web Interoperability Testbed Results Incorporating Earth Observation Satellites

    NASA Technical Reports Server (NTRS)

    Frye, Stuart; Mandl, Daniel J.; Alameh, Nadine; Bambacus, Myra; Cappelaere, Pat; Falke, Stefan; Derezinski, Linda; Zhao, Piesheng

    2007-01-01

    This paper describes an Earth Observation Sensor Web scenario based on the Open Geospatial Consortium s Sensor Web Enablement and Web Services interoperability standards. The scenario demonstrates the application of standards in describing, discovering, accessing and tasking satellites and groundbased sensor installations in a sequence of analysis activities that deliver information required by decision makers in response to national, regional or local emergencies.

  17. Satellite tracking and Earth dynamics research programs

    NASA Technical Reports Server (NTRS)

    Pearlman, M. R.

    1984-01-01

    Following an upgrading program, ranging performance capabilities of a satellite-tracking pulsed laser system were assessed in terms of range accuracy, range noise, data yield, and reliability. With a shorter laser pulse duration (2.5 to 3.0 NSEC) and a new analog pulse processing system, the systematic range errors were reduced to 3 to 5 cm and range noise was reduced to 5 to 16 cm and range noise was reduced to 5 to 15 cm on Starlette and BE-C, and 10 to 18 cm on LAGEOS. Maximum pulse repetition rate was increased to 30 pulses per minute and significant improvement was made in signal to noise ratio by installing a 3 A interference filter and by reducing the range gate window to 200 to 400 nsec. The solution to a problem involving leakage of a fraction of the laser oscillator pulse through the pulse chopper was outlined.

  18. Reconfigurable HIL Testing of Earth Satellites

    NASA Technical Reports Server (NTRS)

    2008-01-01

    In recent years, hardware-in-the-loop (HIL) testing has carved a strong niche in several industries, such as automotive, aerospace, telecomm, and consumer electronics. As desktop computers have realized gains in speed, memory size, and data storage capacity, hardware/software platforms have evolved into high performance, deterministic HIL platforms, capable of hosting the most demanding applications for testing components and subsystems. Using simulation software to emulate the digital and analog I/O signals of system components, engineers of all disciplines can now test new systems in realistic environments to evaluate their function and performance prior to field deployment. Within the Aerospace industry, space-borne satellite systems are arguably some of the most demanding in terms of their requirement for custom engineering and testing. Typically, spacecraft are built one or few at a time to fulfill a space science or defense mission. In contrast to other industries that can amortize the cost of HIL systems over thousands, even millions of units, spacecraft HIL systems have been built as one-of-a-kind solutions, expensive in terms of schedule, cost, and risk, to assure satellite and spacecraft systems reliability. The focus of this paper is to present a new approach to HIL testing for spacecraft systems that takes advantage of a highly flexible hardware/software architecture based on National Instruments PXI reconfigurable hardware and virtual instruments developed using LabVIEW. This new approach to HIL is based on a multistage/multimode spacecraft bus emulation development model called Reconfigurable Hardware In-the-Loop or RHIL.

  19. Model of load distribution for earth observation satellite

    NASA Astrophysics Data System (ADS)

    Tu, Shumin; Du, Min; Li, Wei

    2017-03-01

    For the system of multiple types of EOS (Earth Observing Satellites), it is a vital issue to assure that each type of payloads carried by the group of EOS can be used efficiently and reasonably for in astronautics fields. Currently, most of researches on configuration of satellite and payloads focus on the scheduling for launched satellites. However, the assignments of payloads for un-launched satellites are bit researched, which are the same crucial as the scheduling of tasks. Moreover, the current models of satellite resources scheduling lack of more general characteristics. Referring the idea about roles-based access control (RBAC) of information system, this paper brings forward a model based on role-mining of RBAC to improve the generality and foresight of the method of assignments of satellite-payload. By this way, the assignment of satellite-payload can be mapped onto the problem of role-mining. A novel method will be introduced, based on the idea of biclique-combination in graph theory and evolutionary algorithm in intelligence computing, to address the role-mining problem of satellite-payload assignments. The simulation experiments are performed to verify the novel method. Finally, the work of this paper is concluded.

  20. The earth radiation budget satellite system for climate research

    NASA Technical Reports Server (NTRS)

    Woerner, C. V.; Cooper, J. E.; Harrison, E. F.

    1978-01-01

    The mission implications of providing earth radiation budget data for climate studies have been thoroughly studied. The results of these studies indicate the need for a multisensor, multisatellite system consisting of high and midinclination orbits. To meet this need, NASA and NOAA are planning a joint Earth Radiation Budget Satellite System (ERBSS) composed of instruments on two of NOAA's near-polar Sun-synchronous TIROS-N/NOAA A through G series of operational satellites and on an NASA midinclination satellite of the Applications Explorer Mission (AEM) type referred to as ERBS-A/AEM. This paper describes the scientific objectives of ERBSS, the associated data analysis methods, mission analysis (sampling), and instrument definition.

  1. Planning and Scheduling for Fleets of Earth Observing Satellites

    NASA Technical Reports Server (NTRS)

    Frank, Jeremy; Jonsson, Ari; Morris, Robert; Smith, David E.; Norvig, Peter (Technical Monitor)

    2001-01-01

    We address the problem of scheduling observations for a collection of earth observing satellites. This scheduling task is a difficult optimization problem, potentially involving many satellites, hundreds of requests, constraints on when and how to service each request, and resources such as instruments, recording devices, transmitters, and ground stations. High-fidelity models are required to ensure the validity of schedules; at the same time, the size and complexity of the problem makes it unlikely that systematic optimization search methods will be able to solve them in a reasonable time. This paper presents a constraint-based approach to solving the Earth Observing Satellites (EOS) scheduling problem, and proposes a stochastic heuristic search method for solving it.

  2. The first Earth Resources Technology Satellite (ERTS-1)

    NASA Technical Reports Server (NTRS)

    Nordberg, W.

    1973-01-01

    The first Earth Resources Technology Satellite (ERTS-1) makes images of the earth's surface in four portions of the electromagnetic spectrum with sufficient spatial resolution and with a minimum of geometric distortions, so that these images may be applied experimentally to the study of geophysical processes relating to earth resources, to the exploration and conservation of these resources, and to the assessments of environmental stresses. During the first six months of operation, ERTS-1 has imaged 6.5 million square kilometers of the earth's surface every day, covering most major land masses and coastal zones as well as both polar regions of this planet. These images as well as the results of their analyses are available to all people throughout the world. Scientific investigators of all countries have been invited to participate in the utilization of ERTS-1 observations. Many of them have already demonstrated the great efficiency, economy, and reliability of making earth surveys from space.

  3. Problems in merging Earth sensing satellite data sets

    NASA Technical Reports Server (NTRS)

    Smith, Paul H.; Goldberg, Michael J.

    1987-01-01

    Satellite remote sensing systems provide a tremendous source of data flow to the Earth science community. These systems provide scientists with data of types and on a scale previously unattainable. Looking forward to the capabilities of Space Station and the Earth Observing System (EOS), the full realization of the potential of satellite remote sensing will be handicapped by inadequate information systems. There is a growing emphasis in Earth science research to ask questions which are multidisciplinary in nature and global in scale. Many of these research projects emphasize the interactions of the land surface, the atmosphere, and the oceans through various physical mechanisms. Conducting this research requires large and complex data sets and teams of multidisciplinary scientists, often working at remote locations. A review of the problems of merging these large volumes of data into spatially referenced and manageable data sets is presented.

  4. Simulation of interference between Earth stations and Earth-orbiting satellites

    NASA Technical Reports Server (NTRS)

    Bishop, D. F.

    1994-01-01

    It is often desirable to determine the potential for radio frequency interference between earth stations and orbiting spacecraft. This information can be used to select frequencies for radio systems to avoid interference or it can be used to determine if coordination between radio systems is necessary. A model is developed that will determine the statistics of interference between earth stations and elliptical orbiting spacecraft. The model uses orbital dynamics, detailed antenna patterns, and spectral characteristics to obtain accurate levels of interference at the victim receiver. The model is programmed into a computer simulation to obtain long-term statistics of interference. Two specific examples are shown to demonstrate the model. The first example is a simulation of interference from a fixed-satellite earth station to an orbiting scatterometer receiver. The second example is a simulation of interference from earth-exploration satellites to a deep-space earth station.

  5. Determination of the Earth's lithospheric magnetic field with satellite data

    NASA Astrophysics Data System (ADS)

    Kotsiaros, Stavros; Olsen, Nils; Finlay, Christopher

    2016-07-01

    Satellites such as Magsat, Ørsted, CHAMP and Swarm provide the most effective means of determining on a global scale the Earth's lithospheric magnetic field. In particular, the Swarm three-satellite constellation mission aims at capturing the smallest-scale features of the lithospheric field that have ever been captured from space. To achieve that, explicit advantage of the constellation aspect of Swarm has to be taken by using gradient estimates. We derive lithospheric field models using more than one year of magnetic gradient data, which are approximated by first differences of field vector data between the two lower Swarm satellites and along each satellite orbit, respectively. We find that gradient data are less sensitive to large-scale external field fluctuations. Moreover, gradient data appear to be a very efficient way of increasing the resolution of lithospheric field models and thus providing an initial validation of the gradient concept underlying the Swarm mission.

  6. The NASA Earth Science Program and Small Satellites

    NASA Technical Reports Server (NTRS)

    Neeck, Steven P.

    2015-01-01

    Earth's changing environment impacts every aspect of life on our planet and climate change has profound implications on society. Studying Earth as a single complex system is essential to understanding the causes and consequences of climate change and other global environmental concerns. NASA's Earth Science Division (ESD) shapes an interdisciplinary view of Earth, exploring interactions among the atmosphere, oceans, ice sheets, land surface interior, and life itself. This enables scientists to measure global and climate changes and to inform decisions by Government, other organizations, and people in the United States and around the world. The data collected and results generated are accessible to other agencies and organizations to improve the products and services they provide, including air quality indices, disaster prediction and response, agricultural yield projections, and aviation safety. ESD's Flight Program provides the spacebased observing systems and supporting infrastructure for mission operations and scientific data processing and distribution that support NASA's Earth science research and modeling activities. The Flight Program currently has 21 operating Earth observing space missions, including the recently launched Global Precipitation Measurement (GPM) mission, the Orbiting Carbon Observatory-2 (OCO-2), the Soil Moisture Active Passive (SMAP) mission, and the International Space Station (ISS) RapidSCAT and Cloud-Aerosol Transport System (CATS) instruments. The ESD has 22 more missions and instruments planned for launch over the next decade. These include first and second tier missions from the 2007 Earth Science Decadal Survey, Climate Continuity missions to assure availability of key climate data sets, and small-sized competitively selected orbital missions and instrument missions of opportunity belonging to the Earth Venture (EV) Program. Small satellites (500 kg or less) are critical contributors to these current and future satellite missions

  7. Interdisciplinary Earth Science Applications Using Satellite Radar Altimetry

    NASA Astrophysics Data System (ADS)

    Kuo, C.; Shum, C.; Lee, H.; Dai, C.; Yi, Y.

    2012-12-01

    Satellite altimetry was conceived as a space geodetic concept for ocean surface topography mapping in the NASA-sponsored 1969 Williamstown, MA Conference, and was tested as part of the passive and active radar payload (S192), along with a radiometer and a scatterometer, on Skylab-1 in May 14, 1973. Since then, numerous radar and laser satellite altimetry missions orbiting/flying-by the Earth, Mars, Mercury, Titan and the Moon have been launched, evolving from the original scientific objective of marine gravity field mapping to a geodetic tool to address interdisciplinary Earth and planetary sciences. The accuracy of the radar altimeter has improved from 0.9 m RMS for the S-192 Skylab Ku-band compressed-pulse altimeter, to 2 cm RMS (2 second average) for the dual-frequency pulse-limited radar altimetry and associated sensors onboard TOPEX/POSEIDON. Satellite altimetry has evolved into a unique cross-disciplinary geodetic tool in addressing contemporary Earth science problems including sea-level rise, large-scale general ocean circulation, ice-sheet mass balance, terrestrial hydrology, and bathymetry. Here we provide a concise review and describe specific results on the additional recent innovative and unconventional applications of interdisciplinary science research using satellite radar altimetry, including geodynamics, land subsidence, snow depth, wetland and cold region hydrology.

  8. From Order to Chaos in Earth Satellite Orbits

    NASA Astrophysics Data System (ADS)

    Gkolias, Ioannis; Daquin, Jérôme; Gachet, Fabien; Rosengren, Aaron J.

    2016-11-01

    We consider Earth satellite orbits in the range of semimajor axes where the perturbing effects of Earth’s oblateness and lunisolar gravity are of comparable order. This range covers the medium-Earth orbits (MEO) of the Global Navigation Satellite Systems and the geosynchronous orbits (GEO) of the communication satellites. We recall a secular and quadrupolar model, based on the Milankovitch vector formulation of perturbation theory, which governs the long-term orbital evolution subject to the predominant gravitational interactions. We study the global dynamics of this two-and-a-half degrees-of-freedom Hamiltonian system by means of the fast Lyapunov indicator (FLI), used in a statistical sense. Specifically, we characterize the degree of chaoticity of the action space using angle-averaged normalized FLI maps, thereby overcoming the angle dependencies of the conventional stability maps. Emphasis is placed upon the phase-space structures near secular resonances, which are of primary importance to the space debris community. We confirm and quantify the transition from order to chaos in MEO, stemming from the critical inclinations and find that highly inclined GEO orbits are particularly unstable. Despite their reputed normality, Earth satellite orbits can possess an extraordinarily rich spectrum of dynamical behaviors and, from a mathematical perspective, have all the complications that make them very interesting candidates for testing the modern tools of chaos theory.

  9. Satellite-tracking and earth-dynamics research programs. [NASA Programs on satellite orbits and satellite ground tracks of geodetic satellites

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Observations and research progress of the Smithsonian Astrophysical Observatory are reported. Satellite tracking networks (ground stations) are discussed and equipment (Baker-Nunn cameras) used to observe the satellites is described. The improvement of the accuracy of a laser ranging system of the ground stations is discussed. Also, research efforts in satellite geodesy (tides, gravity anomalies, plate tectonics) is discussed. The use of data processing for geophysical data is examined, and a data base for the Earth and Ocean Physics Applications Program is proposed. Analytical models of the earth's motion (computerized simulation) are described and the computation (numerical integration and algorithms) of satellite orbits affected by the earth's albedo, using computer techniques, is also considered. Research efforts in the study of the atmosphere are examined (the effect of drag on satellite motion), and models of the atmosphere based on satellite data are described.

  10. Satellite emission radio interferometric earth surveying series - GPS geodetic system

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1979-01-01

    A concept called SERIES (satellite emissions radio interferometric earth surveying) which makes use of GPS (global positioning system) radio transmissions without any satellite modifications, is described. Through the use of very long baseline interferometry (VLBI) and its calibration methods, 0.5 to 3 cm three dimensional baseline accuracy can be achieved over distances of 2 to 200 km respectively, with only 2 hours of on-site data acquisition. Attention is given to such areas as: the radio flux equivalent of GPS transmissions, synthesized delay precision, transmission and frequency subsystem requirements, tropospheric and ionospheric errors. Applications covered include geodesy and seismic tectonics.

  11. An Autonomous Orbit Determination System for Earth Satellites

    DTIC Science & Technology

    1989-12-01

    Master’s thesis centered around satellite clusters (43). Using a simplistic model, Ward’s research was a proof-of-concept study into a satellite’s...Ward’s Proposal. In John Ward’s Master’s thesis , he proposed using one or two star sensors and an Earth sensor to determine the orbital elements of a...900 - 1200 " - QDO Total Position RMS Error 1000o QP•qQQ Filter-Computed Position RMS Error S4,4 ,!4L Radial RMS Error LJ 00-00-0 In-Track RMS Error

  12. Re-Evaluating Satellite Solar Power Systems for Earth

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2006-01-01

    The Solar Power Satellite System is a concept to collect solar power in space, and then transport it to the surface of the Earth by microwave (or possibly laser) beam, where if is converted into electrical power for terrestrial use. The recent increase in energy costs, predictions of the near-term exhaustion of oil, and prominence of possible climate change due to the "greenhouse effect" from burning of fossil fuels has again brought alternative energy sources to public attention, and the time is certainly appropriate to reexamine the economics of space based power. Several new concepts for Satellite Power System designs were evaluated to make the concept more economically feasible.

  13. Orbit Determination System for Low Earth Orbit Satellites

    NASA Technical Reports Server (NTRS)

    Elisha, Yossi; Shyldkrot, Haim; Hankin, Maxim

    2007-01-01

    The IAI/MBT Precise Orbit Determination system for Low Earth Orbit satellites is presented. The system is based on GPS pesudorange and carrier phase measurements and implements the Reduced Dynamics method. The GPS measurements model, the dynamic model, and the least squares orbit determination are discussed. Results are shown for data from the CHAMP satellite and for simulated data from the ROKAR GPS receiver. In both cases the one sigma 3D position and velocity accuracy is about 0.2 m and 0.5 mm/sec respectively.

  14. Satellite-tracking and Earth dynamics research programs

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The activities carried out by the Smithsonian Astrophysical Observatory (SAO) are described. The SAO network continued to track LAGEOS at highest priority for polar motion and Earth rotation studies, and for other geophysical investigations, including crustal dynamics, Earth and ocean tides, and the general development of precision orbit determination. The network performed regular tracking of several other retroreflector satellites including GEOS-1, GEOS-3, BE-C, and Starlette for refined determinations of station coordinates and the Earth's gravity field and for studies of solid Earth dynamics. A major program in laser upgrading continued to improve ranging accuracy and data yield. This program includes an increase in pulse repetition rate from 8 ppm to 30 ppm, a reduction in laser pulse width from 6 nsec to 2 to 3 nsec, improvements in the photoreceiver and the electronics to improve daylight ranging, and an analog pulse detection system to improve range noise and accuracy. Data processing hardware and software are discussed.

  15. Integration of satellite fire products into MPI Earth System Model

    NASA Astrophysics Data System (ADS)

    Khlystova, Iryna G.; Kloster, Silvia

    2013-04-01

    Fires are the ubiquitous phenomenon affecting all natural biomes. Since the beginning of the satellite Era, fires are being continuously observed from satellites. The most interesting satellite parameter retrieved from satellite measurements is the burned area. Combined with information on biomass available for burning the burned area can be translated into climate relevant carbon emissions from fires into the atmosphere. In this study we integrate observed burned area into a global vegetation model to derive global fire emissions. Global continuous burned area dataset is provided by the Global Fire Emissions Dataset (GFED). GFED products were obtained from MODIS (and pre-MODIS) satellites and are available for the time period of 14 years (1997-2011). This dataset is widely used, well documented and supported by periodical updates containing new features. We integrate the global burned area product into the land model JSBACH, a part of the Earth-System model developed at the Max Plank Institute for Meteorology. The land model JSBACH simulates land biomass in terms of carbon content. Fire is an important disturbance process in the Earth's carbon cycle and affects mainly the carbon stored in vegetation. In the standard JSBACH version fire is represented by process based algorithms. Using the satellite data as an alternative we are targeting better comparability of modeled carbon emissions with independent satellite measurements of atmospheric composition. The structure of burned vegetation inside of a biome can be described as the balance between woody and herbaceous vegetation. GFED provides in addition to the burned area satellite derived information of the tree cover distribution within the burned area. Using this dataset, we can attribute the burned area to the respective simulated herbaceous or woody biomass within the vegetation model. By testing several extreme cases we evaluate the quantitative impact of vegetation balance between woody and herbaceous

  16. Low Earth Orbit Satellite Tracking Telescope Network: Collaborative Optical Tracking for Enhanced Space Situational Awareness

    DTIC Science & Technology

    2015-03-27

    LOW EARTH ORBIT SATELLITE TRACKING TELESCOPE NETWORK: COLLABORATIVE OPTICAL TRACKING FOR ENHANCED...copyright protection in the United States. AFIT-ENV-MS-15-M-200 LOW EARTH ORBIT SATELLITE TRACKING TELESCOPE NETWORK: COLLABORATIVE OPTICAL...STATEMENT A. APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED. AFIT-ENV-MS-15-M-200 LOW EARTH ORBIT SATELLITE TRACKING TELESCOPE NETWORK

  17. A method for capturing asteroids into earth satellite orbits

    NASA Astrophysics Data System (ADS)

    Ledkov, A. A.; Eismont, N. A.; Nazirov, R. R.; Boyarsky, M. N.

    2015-08-01

    At present, the capture of a suitable asteroid into an Earth satellite orbit is proposed as one of the methods for investigating asteroids within the framework of manned missions. Once the asteroid has been transferred to such an orbit, an expedition with the participation of astronauts is planned to the asteroid surface, where research is carried out and asteroid rock samples are selected and subsequently delivered to the Earth. It is in this way that the American Keck project is described at the current planning and preliminary design stage. In this paper, we solve the capture problem by a method alternative to that planned in the Keck project.

  18. Satellite Motion Effects on Current Collection in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Zhang, T. X.; Hwang, K. S.; Wu, S. T.; Stone, N. H.; Chang, C. L.; Drobot, A.; Wright, K. H., Jr.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    Results from the Tethered Satellite System (TSS) missions unambiguously show that the electrodynamic tether system produced 2 to 3 times the predicted current levels in the tether. The pre-mission predictions were based on the well-known Parker-Murphy (PM) model, which describes the collection of current by an electrically biased satellite in the ionospheric plasma. How the TSS satellite was able to collect 2-3 times the PM current has remained an open question. In the present study, self-consistent potential and motional effects are introduced into the Thompson and Dobrowolny sheath models. As a result, the magnetic field aligned sheath-an essential variable in determining current collection by a satellite-is derived and is shown to be explicitly velocity dependent. The orientation of the satellite's orbital motion relative to the geomagnetic field is also considered in the derivation and a velocity dependent expression for the collected current is obtained. The resulting model provides a realistic treatment of current collection by a satellite in low earth orbit. Moreover, the predictions, using the appropriate parameters for TSS, are in good agreement with the tether currents measured during the TSS-1R mission.

  19. Enhancement of the Natural Earth Satellite Population Through Meteoroid Aerocapture

    NASA Technical Reports Server (NTRS)

    Moorhead, Althea V.; Cooke, William J.

    2014-01-01

    The vast majority of meteoroids either fall to the ground as meteorites or ablate completely in the atmosphere. However, large meteoroids have been observed to pass through the atmosphere and reenter space in a few instances. These atmosphere-grazing meteoroids have been characterized using ground-based observation and satellite-based infrared detection. As these methods become more sensitive, smaller atmospheregrazing meteoroids will likely be detected. In anticipation of this increased detection rate, we compute the frequency with which centimeter-sized meteoroids graze and exit Earth's atmosphere. We characterize the post-atmosphere orbital characteristics of these bodies and conduct numerical simulations of their orbital evolution under the perturbing influence of the Sun and Moon. We find that a small subset of aerocaptured meteoroids are perturbed away from immediate atmospheric reentry and become temporary natural Earth satellites.

  20. Principle characteristics of the National Earth Observation Satellite. Project SPOT

    NASA Technical Reports Server (NTRS)

    Cazenave, M.

    1977-01-01

    A recent meeting of the Economic and Social Committee examined the programs and means currently being implemented by France in the field in the field of space research and industry which could bring about fast results. This was prompted by man's desire to insure rational resource management of his planet and by man's awareness of the definite contribution that space observation can make to this field of research. Through discussion, the Economic and Social Committee has approved the plan for creating an earth observation satellite. A detailed discussion of the principle characteristics of this earth observation satellite include the objectives, the orbit, characteristics and operations of the platform, maintenance, attitude measurement, the power available and many other characteristics.

  1. The Theory of Artificial Satellites in Terms of the Orbital True Longitude

    NASA Technical Reports Server (NTRS)

    Musen, Peter

    1961-01-01

    The author's previous theory of the artificial satellite is derived in terms of the. disturbed eccentric anomaly. The present development, in terms of the orbital true longitude, is a substantial improvement over the earlier work in that it leads to the faster convergence for large eccentricities and to a smaller number of terms in the series representing the perturbations. Moreover, each approximation of the radius vector and of the parameters determining the position of the orbit plane is obtained not in the form of a truncated infinite series but in the form of trigonometric polynomials in two arguments. These arguments are the mean true anomaly and the mean argument of the latitude. The present theory, like the previous one, permits the computation of perturbations of any desired order. Thus, any future information about earth's gravitational field can easily be included.

  2. Space simulation testing of the Earth Radiation Budget Satellite (ERBS)

    NASA Technical Reports Server (NTRS)

    Magette, E.; Smith, D.

    1984-01-01

    The Earth radiation budget components and dynamics and the interactions of this energy cycle, which influences our climate were investigated. The satellite package was subjected to space simulation testing. The size of the spacecraft dictated that the testing be conducted in the new BRUTUS Thermal Vacuum Facility. Computer aided control (CAC), quartz crystal microbalance (QCM), and residual gas analysis (RGA) monitoring are combined with rigid contamination control procedures to protect the flight hardware from anomalous and potentially destructive out of scope test environments.

  3. Management approach recommendations. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Management analyses and tradeoffs were performed to determine the most cost effective management approach for the Earth Observatory Satellite (EOS) Phase C/D. The basic objectives of the management approach are identified. Some of the subjects considered are as follows: (1) contract startup phase, (2) project management control system, (3) configuration management, (4) quality control and reliability engineering requirements, and (5) the parts procurement program.

  4. Electric Propulsion for Low Earth Orbit Communication Satellites

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.

    1997-01-01

    Electric propulsion was evaluated for orbit insertion, satellite positioning and de-orbit applications on big (hundreds of kilograms) and little (tens of kilograms) low earth orbit communication satellite constellations. A simple, constant circumferential thrusting method was used. This technique eliminates the complex guidance and control required when shading of the solar arrays must be considered. Power for propulsion was assumed to come from the existing payload power. Since the low masses of these satellites enable multiple spacecraft per launch, the ability to add spacecraft to a given launch was used as a figure of merit. When compared to chemical propulsion ammonia resistojets, ion, Hall, and pulsed plasma thrusters allowed an additional spacecraft per launch Typical orbit insertion and de-orbit times were found to range from a few days to a few months.

  5. Tracking target objects orbiting earth using satellite-based telescopes

    DOEpatents

    De Vries, Willem H; Olivier, Scot S; Pertica, Alexander J

    2014-10-14

    A system for tracking objects that are in earth orbit via a constellation or network of satellites having imaging devices is provided. An object tracking system includes a ground controller and, for each satellite in the constellation, an onboard controller. The ground controller receives ephemeris information for a target object and directs that ephemeris information be transmitted to the satellites. Each onboard controller receives ephemeris information for a target object, collects images of the target object based on the expected location of the target object at an expected time, identifies actual locations of the target object from the collected images, and identifies a next expected location at a next expected time based on the identified actual locations of the target object. The onboard controller processes the collected image to identify the actual location of the target object and transmits the actual location information to the ground controller.

  6. Magnus Effect on a Spinning Satellite in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Ramjatan, Sahadeo; Fitz-Coy, Norman; Yew, Alvin Garwai

    2016-01-01

    A spinning body in a flow field generates an aerodynamic lift or Magnus effect that displaces the body in a direction normal to the freestream flow. Earth orbiting satellites with substantial body rotation in appreciable atmospheric densities may generate a Magnus force to perturb orbital dynamics. We investigate the feasibility of using this effect for spacecraft at a perigee of 80km using the Systems Tool Kit (STK). Results show that for a satellite of reasonable properties, the Magnus effect doubles the amount of time in orbit. Orbital decay was greatly mitigated for satellites spinning at 10000 and 15000RPM. This study demonstrates that the Magnus effect has the potential to sustain a spacecraft's orbit at a low perigee altitude and could also serve as an orbital maneuver capability.

  7. Use of Earth Observing Satellites for Operational Hazard Support

    NASA Astrophysics Data System (ADS)

    Wood, H. M.; Lauritson, L.

    The National Oceanic and Atmospheric Administration (NOAA) relies on Earth observing satellite data to carry out its operational mission to monitor, predict, and assess changes in the Earth's atmosphere, land, and oceans. NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) uses satellite data to help lessen the impacts of natural and man-made disasters due to tropical cyclones, flash floods, heavy snowstorms, volcanic ash clouds (for aviation safety), sea ice (for shipping safety), and harmful algal blooms. Communications systems on NOAA satellites are used to support search and rescue and to relay data from data collection platforms to a variety of users. NOAA's Geostationary (GOES) and Polar (POES) Operational Environmental Satellites are used in conjunction with other satellites to support NOAA's operational mission. While NOAA's National Hurricane Center is responsible for predicting tropical cyclones affecting the U.S. mainland, NESDIS continuously monitors the tropics world wide, relaying valuable satellite interpretations of tropical systems strength and position to users throughout the world. Text messages are sent every six hours for tropical cyclones in the Western Pacific, South Pacific, and Indian Oceans. To support the monitoring, prediction, and assessment of flash floods and winter storms, NESDIS sends out text messages alerting U.S. weather forecast offices whenever NOAA satellite imagery indicates the occurrence of heavy rain or snow. NESDIS also produces a 24-hour rainfall composite graphic image covering those areas affected by heavy precipitation. The International Civil Aviation Organization (ICAO) and other aviation concerns recognized the need to keep aviators informed of volcanic hazards. To that end, nine Volcanic Ash Advisory Centers (VAAC's) were created to monitor volcanic ash plumes within their assigned airspace. NESDIS hosts one of the VAAC's. Although the NESDIS VAAC's primary responsibility is the

  8. Satellite Detection of the Convection Generated Stresses in Earth

    NASA Technical Reports Server (NTRS)

    Liu, Han-Shou; Kolenkiewicz, Ronald; Li, Jin-Ling; Chen, Jiz-Hong

    2003-01-01

    We review research developments on satellite detection of the convection generated stresses in the Earth for seismic hazard assessment and Earth resource survey. Particular emphasis is laid upon recent progress and results of stress calculations from which the origin and evolution of the tectonic features on Earth's surface can be scientifically addressed. An important aspect of the recent research development in tectonic stresses relative to earthquakes is the implications for earthquake forecasting and prediction. We have demonstrated that earthquakes occur on the ring of fire around the Pacific in response to the tectonic stresses induced by mantle convection. We propose a systematic global assessment of the seismic hazard based on variations of tectonic stresses in the Earth as observed by satellites. This space geodynamic approach for assessing the seismic hazard is unique in that it can pinpoint the triggering stresses for large earthquakes without ambiguities of geological structures, fault geometries, and other tectonic properties. Also, it is distinct from the probabilistic seismic hazard assessment models in the literature, which are based only on extrapolations of available earthquake data.

  9. Earth's Radiation Imbalance from a Constellation of 66 Iridium Satellites

    NASA Astrophysics Data System (ADS)

    Chiu, J. C.; Wiscombe, W. J.

    2012-04-01

    The Earth Radiation Imbalance (ERI) at the top of the atmosphere is the primary driving force for climate change. If ERI is not zero, then Earth's temperature, both oceanic and atmospheric, will change gradually over time, tending toward a new steady state. The best estimates of current ERI from climate models range from 0.4 to 0.9 W/m2 (the imbalance being caused mainly by increasing CO2), but current satellite systems do not have the accuracy to measure ERI to even one significant digit. In this paper, we will describe a proposed constellation of 66 Earth radiation budget instruments, to be hosted on Iridium satellites. This system represents a quantum leap over current systems in several ways, in particular in providing ERI to at least one significant digit, thus enabling a crucial test of climate models. Because of its 24/7 coverage, the system will also provide ERI at three-hourly time scales without requiring extrapolations from narrowband geostationary instruments. This would allow studies of ERI's response to fast-evolving phenomena like dust storms and hurricanes. This offers a new, synoptic view of Earth radiation budget that will transform it from a monthly average into a dynamical variable alongside standard meteorological variables like temperature and pressure.

  10. Harnessing Satellite Imageries in Feature Extraction Using Google Earth Pro

    NASA Astrophysics Data System (ADS)

    Fernandez, Sim Joseph; Milano, Alan

    2016-07-01

    Climate change has been a long-time concern worldwide. Impending flooding, for one, is among its unwanted consequences. The Phil-LiDAR 1 project of the Department of Science and Technology (DOST), Republic of the Philippines, has developed an early warning system in regards to flood hazards. The project utilizes the use of remote sensing technologies in determining the lives in probable dire danger by mapping and attributing building features using LiDAR dataset and satellite imageries. A free mapping software named Google Earth Pro (GEP) is used to load these satellite imageries as base maps. Geotagging of building features has been done so far with the use of handheld Global Positioning System (GPS). Alternatively, mapping and attribution of building features using GEP saves a substantial amount of resources such as manpower, time and budget. Accuracy-wise, geotagging by GEP is dependent on either the satellite imageries or orthophotograph images of half-meter resolution obtained during LiDAR acquisition and not on the GPS of three-meter accuracy. The attributed building features are overlain to the flood hazard map of Phil-LiDAR 1 in order to determine the exposed population. The building features as obtained from satellite imageries may not only be used in flood exposure assessment but may also be used in assessing other hazards and a number of other uses. Several other features may also be extracted from the satellite imageries.

  11. An Earth Orbiting Satellite Service and Repair Facility

    NASA Technical Reports Server (NTRS)

    Berndt, Andrew; Cardoza, Mike; Chen, John; Daley, Gunter; Frizzell, Andy; Linton, Richard; Rast, Wayne

    1989-01-01

    A conceptual design was produced for the Geosynchronous Satellite Servicing Platform (GSSP), an orbital facility capable of repairing and servicing satellites in geosynchronous orbit. The GSSP is a man-tended platform, which consists of a habitation module, operations module, service bay and truss assembly. This design review includes an analysis of life support systems, thermal and power requirements, robotic and automated systems, control methods and navigation, and communications systems. The GSSP will utilize existing technology available at the time of construction, focusing mainly on modifying and integrating existing systems. The entire facility, along with two satellite retrieval vehicles (SRV), will be placed in geosynchronous orbit by the Advanced Launch System. The SRV will be used to ferry satellites to and from the GSSP. Technicians will be transferred from Earth to the GSSP and back in an Apollo-derived Crew Transfer Capsule (CTC). These missions will use advanced telerobotic equipment to inspect and service satellites. Four of these missions are tentatively scheduled per year. At this rate, the GSSP will service over 650 satelites during the projected 25 year lifespan.

  12. Experimental quasi-single-photon transmission from satellite to earth.

    PubMed

    Yin, Juan; Cao, Yuan; Liu, Shu-Bin; Pan, Ge-Sheng; Wang, Jin-Hong; Yang, Tao; Zhang, Zhong-Ping; Yang, Fu-Min; Chen, Yu-Ao; Peng, Cheng-Zhi; Pan, Jian-Wei

    2013-08-26

    Free-space quantum communication with satellites opens a promising avenue for global secure quantum network and large-scale test of quantum foundations. Recently, numerous experimental efforts have been carried out towards this ambitious goal. However, one essential step--transmitting single photons from the satellite to the ground with high signal-to-noise ratio (SNR) at realistic environments--remains experimental challenging. Here, we report a direct experimental demonstration of the satellite-ground transmission of a quasi-single-photon source. In the experiment, single photons (~0.85 photon per pulse) are generated by reflecting weak laser pulses back to earth with a cube-corner retro-reflector on the satellite CHAMP, collected by a 600-mm diameter telescope at the ground station, and finally detected by single-photon counting modules after 400-km free-space link transmission. With the help of high accuracy time synchronization, narrow receiver field-of-view and high-repetition-rate pulses (76 MHz), a SNR of better than 16:1 is obtained, which is sufficient for a secure quantum key distribution. Our experimental results represent an important step towards satellite-ground quantum communication.

  13. Earth-viewing satellite perspectives on the Chelyabinsk meteor event.

    PubMed

    Miller, Steven D; Straka, William C; Bachmeier, A Scott; Schmit, Timothy J; Partain, Philip T; Noh, Yoo-Jeong

    2013-11-05

    Large meteors (or superbolides [Ceplecha Z, et al. (1999) Meteoroids 1998:37-54]), although rare in recorded history, give sobering testimony to civilization's inherent vulnerability. A not-so-subtle reminder came on the morning of February 15, 2013, when a large meteoroid hurtled into the Earth's atmosphere, forming a superbolide near the city of Chelyabinsnk, Russia, ∼1,500 km east of Moscow, Russia [Ivanova MA, et al. (2013) Abstracts of the 76th Annual Meeting of the Meteoritical Society, 5366]. The object exploded in the stratosphere, and the ensuing shock wave blasted the city of Chelyabinsk, damaging structures and injuring hundreds. Details of trajectory are important for determining its specific source, the likelihood of future events, and potential mitigation measures. Earth-viewing environmental satellites can assist in these assessments. Here we examine satellite observations of the Chelyabinsk superbolide debris trail, collected within minutes of its entry. Estimates of trajectory are derived from differential views of the significantly parallax-displaced [e.g., Hasler AF (1981) Bull Am Meteor Soc 52:194-212] debris trail. The 282.7 ± 2.3° azimuth of trajectory, 18.5 ± 3.8° slope to the horizontal, and 17.7 ± 0.5 km/s velocity derived from these satellites agree well with parameters inferred from the wealth of surface-based photographs and amateur videos. More importantly, the results demonstrate the general ability of Earth-viewing satellites to provide valuable insight on trajectory reconstruction in the more likely scenario of sparse or nonexistent surface observations.

  14. Small Earth Observing Satellites Flying with Large Satellites in the A-Train

    NASA Technical Reports Server (NTRS)

    Kelly, Angelita C.; Loverro, Adam; Case, Warren F.; Queruel, Nadege; Marechal, Chistophe; Barroso, Therese

    2009-01-01

    This paper/poster presents a real-life example of the benefits of flying small satellites with other satellites, large or small, and vice versa. Typically, most small satellites fly payloads consisting of one or two instruments and fly in orbits that are independent from that of other satellites. The science data from these satellites are either used in isolation or correlated with instrument data from other satellites. Data correlation with other satellites is greatly improved when the measurements of the same point or air mass are taken at approximately the same time. Scientists worldwide are beginning to take advantage of the opportunities for improved data correlation, or coincidental science, offered by the international Earth Observing Constellation known as the A-Train (sometimes referred to as the Afternoon Constellation). Most of the A-Train satellites are small - the A-Train is anchored by two large NASA satellites (EOS-Aqua and EOS-Aura), but consists also of 5 small satellites (CloudSat, CALIPSO, PARASOL, OCO and Glory these last two will join in 2009). By flying in a constellation, each mission benefits from coincidental observations from instruments on the other satellites in the constellation. Essentially, from a data point of view, the A-Train can be envisioned as a single, virtual science platform with multiple instruments. Satellites in the A-Train fly at 705 km in sun-synchronous orbits. Their mean local times at the equator are within seconds to a few minutes of each other. This paper describes the challenges of operating an international constellation of independent satellites from the U.S. and Europe to maximize the coincidental science opportunities while at the same time minimizing the level of operational interactions required between team members. The A-Train mission teams have been able to demonstrate that flying as members of an international constellation does not take away the flexibility to accommodate new requirements. Specific

  15. Satellite Emission Range Inferred Earth Survey (SERIES) project

    NASA Technical Reports Server (NTRS)

    Buennagel, L. A.; Macdoran, P. F.; Neilan, R. E.; Spitzmesser, D. J.; Young, L. E.

    1984-01-01

    The Global Positioning System (GPS) was developed by the Department of Defense primarily for navigation use by the United States Armed Forces. The system will consist of a constellation of 18 operational Navigation Satellite Timing and Ranging (NAVSTAR) satellites by the late 1980's. During the last four years, the Satellite Emission Range Inferred Earth Surveying (SERIES) team at the Jet Propulsion Laboratory (JPL) has developed a novel receiver which is the heart of the SERIES geodetic system designed to use signals broadcast from the GPS. This receiver does not require knowledge of the exact code sequence being transmitted. In addition, when two SERIES receivers are used differentially to determine a baseline, few cm accuracies can be obtained. The initial engineering test phase has been completed for the SERIES Project. Baseline lengths, ranging from 150 meters to 171 kilometers, have been measured with 0.3 cm to 7 cm accuracies. This technology, which is sponsored by the NASA Geodynamics Program, has been developed at JPL to meet the challenge for high precision, cost-effective geodesy, and to complement the mobile Very Long Baseline Interferometry (VLBI) system for Earth surveying.

  16. A Modified Hansen's Theory as Applied to the Motion of Artificial Satellites

    NASA Technical Reports Server (NTRS)

    Musen, Peter

    1960-01-01

    This report presents a theory of oblateness perturbations of the orbits of artificial satellites based on Hansen's theory, with modification for adaptation to fast machine computation. The theory permits the easy inclusion of any gravitational terms and is suitable for the deduction of geo-physical and geodetic data from orbit observations on artificial satellites. The computations can be carried out to any desired order compatible with the accuracy of the geodetic parameters.

  17. Low earth orbit satellite/terrestrial mobile service compatibility

    NASA Technical Reports Server (NTRS)

    Sheriff, R. E.; Gardiner, J. G.

    1993-01-01

    Digital cellular mobile 'second generation' systems are now gradually being introduced into service; one such example is GSM, which will provide a digital voice and data service throughout Europe. Total coverage is not expected to be achieved until the mid '90's, which has resulted in several proposals for the integration of GSM with a geostationary satellite service. Unfortunately, because terrestrial and space systems have been designed to optimize their performance for their particular environment, integration between a satellite and terrestrial system is unlikely to develop further than the satellite providing a back-up service. This lack of system compatibility is now being addressed by system designers of third generation systems. The next generation of mobile systems, referred to as FPLMTS (future public land mobile telecommunication systems) by CCIR and UMTS (universal mobile telecommunication system) in European research programs, are intended to provide inexpensive, hand-held terminals that can operate in either satellite, cellular, or cordless environments. This poses several challenges for system designers, not least in terms of the choice of multiple access technique and power requirements. Satellite mobile services have been dominated by the geostationary orbital type. Recently, however, a number of low earth orbit configurations have been proposed, for example Iridium. These systems are likely to be fully operational by the turn of the century, in time for the implementation of FPLMTS. The developments in LEO mobile satellite service technology were recognized at WARC-92 with the allocation of specific frequency bands for 'big' LEO's, as well as a frequency allocation for FPLMTS which included a specific satellite allocation. When considering integrating a space service into the terrestrial network, LEO's certainly appear to have their attractions: they can provide global coverage, the round trip delay is of the order of tens of milliseconds, and

  18. Risk Reduction Activities for the Near-Earth Object Surveillance Satellite Project

    NASA Astrophysics Data System (ADS)

    Bédard, D.; Scott, L.; Wallace, B.; Harvey, W.

    The Near-Earth Object Surveillance Satellite (NEOSSat) is a joint project between Defence Research and Development Canada (DRDC) and the Canadian Space Agency (CSA). The NEOSSat project will develop a multi-mission micro-satellite bus that is expected to satisfy two concurrent missions: detection and tracking near-Earth asteroids (Near Earth Space Surveillance: NESS) and obtaining metric information on deep-space satellites (High Earth Orbit Surveillance System: HEOSS). The former will use NEOSSat's 15 cm diameter space telescope to discover and determine the orbits of inner Earth orbit (IEO) near-earth objects (NEOs) that cannot be easily observed from the ground. For its part, the HEOSS mission will demonstrate that a micro-satellite can be employed to produce surveillance of space (SofS) metric data of artificial earth-orbiting objects having orbital altitudes between 15,000 and 40,000 km having sufficient quality to be accepted by the U.S. Space Surveillance Network. As a risk reduction effort for the NEOSSat project, a joint satellite tracking experiment was conducted by DRDC, CSA, the University of British Columbia and Dynacon using the MOST (Microvariability Oscillations of STars) microsatellite. MOST conducts precision photometric observations of bright stars and does not usually image starfields, but in October 2005, MOST returned Canada's first space based satellite tracking observations of two GPS spacecraft. Good quality metric tracking data were obtained despite the fact MOST was not designed to image, let alone attempt satellite tracking. The observations also provided an estimate of the targeted satellite brightness and the results were consistent with ground based V-band observations. These results demonstrate the soundness of the NEOSSat concept and the feasibility of the HEOSS mission. The nature of both science missions will require the NEOSSat sensor to be pointed to a different position in the sky on average every five minutes, with a goal of

  19. The spatial resolving power of earth resources satellites: A review

    NASA Technical Reports Server (NTRS)

    Townshend, J. R. G.

    1980-01-01

    The significance of spatial resolving power on the utility of current and future Earth resources satellites is critically discussed and the relative merits of different approaches in defining and estimating spatial resolution are outlined. It is shown that choice of a particular measure of spatial resolution depends strongly on the particular needs of the user. Several experiments have simulated the capabilities of future satellite systems by degradation of aircraft images. Surprisingly, many of these indicated that improvements in resolution may lead to a reduction in the classification accuracy of land cover types using computer assisted methods. However, where the frequency of boundary pixels is high, the converse relationship is found. Use of imagery dependent upon visual interpretation is likely to benefit more consistently from higher resolutions. Extraction of information from images will depend upon several other factors apart from spatial resolving power: these include characteristics of the terrain being sensed, the image processing methods that are applied as well as certain sensor characteristics.

  20. Satellite-tracking and earth-dynamics research programs. [geodetic and geophysical investigations and atmospheric research using satellite drag data

    NASA Technical Reports Server (NTRS)

    1972-01-01

    Satellite tracking and earth dynamics research programs are discussed. Geodetic and geophysical investigations are reported along with atmospheric research using satellite drag data. Satellite tracking network functions and support groups which are discussed include: network operations, communications, data-services division, moonwatch, and programming group.

  1. Earth-viewing satellite perspectives on the Chelyabinsk meteor event

    PubMed Central

    Miller, Steven D.; Straka, William C.; Bachmeier, A. Scott; Schmit, Timothy J.; Partain, Philip T.; Noh, Yoo-Jeong

    2013-01-01

    Large meteors (or superbolides [Ceplecha Z, et al. (1999) Meteoroids 1998:37–54]), although rare in recorded history, give sobering testimony to civilization’s inherent vulnerability. A not-so-subtle reminder came on the morning of February 15, 2013, when a large meteoroid hurtled into the Earth’s atmosphere, forming a superbolide near the city of Chelyabinsnk, Russia, ∼1,500 km east of Moscow, Russia [Ivanova MA, et al. (2013) Abstracts of the 76th Annual Meeting of the Meteoritical Society, 5366]. The object exploded in the stratosphere, and the ensuing shock wave blasted the city of Chelyabinsk, damaging structures and injuring hundreds. Details of trajectory are important for determining its specific source, the likelihood of future events, and potential mitigation measures. Earth-viewing environmental satellites can assist in these assessments. Here we examine satellite observations of the Chelyabinsk superbolide debris trail, collected within minutes of its entry. Estimates of trajectory are derived from differential views of the significantly parallax-displaced [e.g., Hasler AF (1981) Bull Am Meteor Soc 52:194–212] debris trail. The 282.7 ± 2.3° azimuth of trajectory, 18.5 ± 3.8° slope to the horizontal, and 17.7 ± 0.5 km/s velocity derived from these satellites agree well with parameters inferred from the wealth of surface-based photographs and amateur videos. More importantly, the results demonstrate the general ability of Earth-viewing satellites to provide valuable insight on trajectory reconstruction in the more likely scenario of sparse or nonexistent surface observations. PMID:24145398

  2. Computer simulation results of attitude estimation of earth orbiting satellites

    NASA Technical Reports Server (NTRS)

    Kou, S. R.

    1976-01-01

    Computer simulation results of attitude estimation of Earth-orbiting satellites (including Space Telescope) subjected to environmental disturbances and noises are presented. Decomposed linear recursive filter and Kalman filter were used as estimation tools. Six programs were developed for this simulation, and all were written in the basic language and were run on HP 9830A and HP 9866A computers. Simulation results show that a decomposed linear recursive filter is accurate in estimation and fast in response time. Furthermore, for higher order systems, this filter has computational advantages (i.e., less integration errors and roundoff errors) over a Kalman filter.

  3. Navigation study for low-altitude Earth satellites

    NASA Technical Reports Server (NTRS)

    Pastor, P. R.; Fang, B. T.; Yee, C. P.

    1985-01-01

    This document describes several navigation studies for low-altitude Earth satellites. The use of Global Positioning System Navigation Package data for LANDSAT-5 orbit determination is evaluated. In addition, a navigation analysis for the proposed Tracking and Data Aquisition System is presented. This analysis, based on simulations employing one-way Doppler data, is used to determine the agreement between the Research and Development Goddard Trajectory Determination System and the Sequential Error Analysis Program results. Properties of several geopotential error models are studied and an exploratory study of orbit smoother process noise is presented.

  4. NASDA's earth observation satellite data archive policy for the earth observation data and information system (EOIS)

    NASA Technical Reports Server (NTRS)

    Sobue, Shin-ichi; Yoshida, Fumiyoshi; Ochiai, Osamu

    1996-01-01

    NASDA's new Advanced Earth Observing Satellite (ADEOS) is scheduled for launch in August, 1996. ADEOS carries 8 sensors to observe earth environmental phenomena and sends their data to NASDA, NASA, and other foreign ground stations around the world. The downlink data bit rate for ADEOS is 126 MB/s and the total volume of data is about 100 GB per day. To archive and manage such a large quantity of data with high reliability and easy accessibility it was necessary to develop a new mass storage system with a catalogue information database using advanced database management technology. The data will be archived and maintained in the Master Data Storage Subsystem (MDSS) which is one subsystem in NASDA's new Earth Observation data and Information System (EOIS). The MDSS is based on a SONY ID1 digital tape robotics system. This paper provides an overview of the EOIS system, with a focus on the Master Data Storage Subsystem and the NASDA Earth Observation Center (EOC) archive policy for earth observation satellite data.

  5. The Near Earth Object Surveillance Satellite (NEOSSat), a Survey Telescope on a Micro-Satellite Platform

    NASA Astrophysics Data System (ADS)

    Laurin, Denis; Hildebrand, A.; Cardinal, R.; Harvey, W.; Tafazoli, S.; Doherty, J.

    2009-01-01

    Although ground-based telescopes have made significant progress in finding near-Earth asteroids (NEA's), marked advantage exist in performing the search from space. The ability to search the ecliptic plane at closer elongations to the Sun, use parallax to discriminate NEA's from those of the Main Belt through distance determinations, and being able to observe continuously are the most significant advantages of a space platform. The Canadian Space Agency (CSA) together with Defense Research and Development Canada (DRDC) are building a micro-satellite platform with a 15 cm telescope dedicated for near space surveillance. The NEOSSat (Near Earth Object Surveillance) spacecraft is expected to be able to detect 20 V magnitude objects with a 100 sec exposure, with a 0.86 deg FOV, on a 1024x1024 CCD, and sub-arcsecond pointing stability. For discovery of NEA's, it will search an area from 45 to 55 degrees solar elongation along the ecliptic plane and ± 40 degrees ecliptic latitude. The observation strategy will be optimized, based upon recent models of the NEA population. Ground-based telescopes will also be used to do follow-ups for orbit determination when possible. The micro-satellite bus and instrument are based on the successful CSA MOST micro-satellite, operating on orbit since 2003. NEOSSat is a shared project with DRDC who will demonstrate the capability of an inexpensive space platform to detect high earth-orbiting satellites and debris (High Earth Orbit Space Surveillance - HEOSS). NEOSSat is base lined for launch in 2010.

  6. Artificially produced rare-earth free cosmic magnet

    PubMed Central

    Makino, Akihiro; Sharma, Parmanand; Sato, Kazuhisa; Takeuchi, Akira; Zhang, Yan; Takenaka, Kana

    2015-01-01

    Chemically ordered hard magnetic L10-FeNi phase of higher grade than cosmic meteorites is produced artificially. Present alloy design shortens the formation time from hundreds of millions of years for natural meteorites to less than 300 hours. Electron diffraction detects four-fold 110 superlattice reflections and a high chemical order parameter (S  0.8) for the developed L10-FeNi phase. The magnetic field of more than 3.5 kOe is required for the switching of magnetization. Experimental results along with computer simulation suggest that the ordered phase is formed due to three factors related to the amorphous state: high diffusion rates of the constituent elements at lower temperatures when crystallizing, a large driving force for precipitation of the L10 phase, and the possible presence of L10 clusters. Present results can resolve mineral exhaustion issues in the development of next-generation hard magnetic materials because the alloys are free from rare-earth elements, and the technique is well suited for mass production. PMID:26567704

  7. Measurement of Artificial-Satellite Spectra with a Small Telescope

    DTIC Science & Technology

    2007-02-01

    context, satellites positions must be frequently reacquired to maintain an accurate knowledge of their orbital parameters . However, acquiring several...positions must be reacquired frequently to maintain an accurate knowledge of their orbital parameters . However, acquiring several satellites in the...continuously combined with rapid variations of satellite orbital parameters . Those orbital characteristic changes account for many missing objects and are

  8. Co-ordination of satellite and data programs: The committee on earth observation satellites' approach

    NASA Astrophysics Data System (ADS)

    Embleton, B. J. J.; Kingwell, J.

    1997-01-01

    Every year, an average of eight new civilian remote sensing satellite missions are launched. Cumulatively, over 250 such missions, each with a cost equivalent in current value to between US 100 million to US 1000 million, have been sponsored by space agencies in perhaps two dozen countries. These missions produce data and information products which are vital for informed decision making all over the world, on matters relating to natural resource exploitation, health and safety, sustainable national development, infrastructure planning, and a host of other applications. By contributing to better scientific understanding of global changes in the atmosphere, land surface, oceans and ice caps, these silently orbiting sentinels in the sky make it possible for governments and industries to make wiser environmental policy decisions and support the economic development needs of humanity. The international Committee on Earth Observation Satellites (CEOS) is the premier world body for co-ordinating and planning civilian satellite missions for Earth observation. Through its technical working groups and special task teams, it endeavours to: • maximise the international benefits from Earth observation satellites; and • harmonise practice in calibration, validation, data management and information systems for Earth observation. CEOS encompasses not only space agencies (data providers), but also the great international scientific and operational programs which rely on Earth science data from space. The user organisations affiliated with CEOS, together with the mission operators, attempt to reconcile user needs with the complex set of considerations — including national interests, cost, schedule — which affect the undertaking of space missions. Without such an internationally co-ordinated consensual approach, there is a much greater risk of waste through duplication, and of missed opportunity, or through the absence of measurements of some vital physical or biological

  9. Solar power satellites: our next generation of satellites will deliver the sun's energy to Earth

    NASA Astrophysics Data System (ADS)

    Flournoy, Don M.

    2009-12-01

    The paper addresses the means for gathering energy from sunlight in space and transmitting it to Earth via Solar Power Satellites. The motivating factor is that the output of our sun is the largest potential energy source available, with the capability of providing inexhaustible quantities of clean electrical energy to every location on Earth. The challenge is that considerable financial, intellectual and diplomatic resources must be focused on designing and implementing new types of energy infrastructures in space and on the ground. These include: 1) next-generation space platforms, arrays, and power transmission systems; 2) more flexible and powerful launch vehicles for delivering materials to space; 3) specialized receivers, converters and storage systems on earth, and the in-orbit position allocations, spectrum and software that make these systems work together efficiently and safely.

  10. Stellar Source Selections for Image Validation of Earth Observation Satellite

    NASA Astrophysics Data System (ADS)

    Yu, Jiwoong; Park, Sang-Young; Lim, Dongwook; Lee, Dong-Han; Sohn, Young-Jong

    2011-12-01

    A method of stellar source selection for validating the quality of image is investigated for a low Earth orbit optical remote sensing satellite. Image performance of the optical payload needs to be validated after its launch into orbit. The stellar sources are ideal source points that can be used to validate the quality of optical images. For the image validation, stellar sources should be the brightest as possible in the charge-coupled device dynamic range. The time delayed and integration technique, which is used to observe the ground, is also performed to observe the selected stars. The relations between the incident radiance at aperture and V magnitude of a star are established using Gunn & Stryker's star catalogue of spectrum. Applying this result, an appropriate image performance index is determined, and suitable stars and areas of the sky scene are selected for the optical payload on a remote sensing satellite to observe. The result of this research can be utilized to validate the quality of optical payload of a satellite in orbit.

  11. Earth Camp: Exploring Earth Change through the Use of Satellite Images and Scientific Practices

    NASA Astrophysics Data System (ADS)

    Baldridge, A.; Buxner, S.; Crown, D. A.; Colodner, D.; Orchard, A.; King, B.; Schwartz, K.; Prescott, A.; Prietto, J.; Titcomb, A.

    2014-07-01

    Earth Camp is a NASA-funded program that gives students and teachers opportunities to explore local, regional, and global earth change through a combination of hands-on investigations and the use of satellite images. Each summer, 20 middle school and 20 high school students participate in a two-week leadership program investigating contemporary issues (e.g., changes in river sheds, water quality, and land use management) through hands-on investigations, analyzing remote sensing data, and working with experts. Each year, 20 teachers participate in a year-long professional development program that includes monthly workshops, field investigations on Mt. Lemmon in Tucson, Arizona, and a week-long summer design workshop. Teachers conduct investigations of authentic questions using satellite images and create posters to present results of their study of earth change. In addition, teachers design lesson plans to expand their students' ability to investigate earth change with 21st Century tools. Lessons can be used as classroom exercises or for after-school club programs. Independent evaluation has been an integral part of program development and delivery for all three audiences, enabling the program staff and participants to reflect on and continually improve their practice and learning over the three-year period.

  12. Mapping of satellite Earth observations using moving window block kriging

    NASA Astrophysics Data System (ADS)

    Tadić, J. M.; Qiu, X.; Yadav, V.; Michalak, A. M.

    2015-10-01

    Global gridded maps (a.k.a. Level 3 products) of Earth system properties observed by satellites are central to understanding the spatiotemporal variability of these properties. They also typically serve either as inputs into biogeochemical models or as independent data for evaluating such models. Spatial binning is a common method for generating contiguous maps, but this approach results in a loss of information, especially when the measurement noise is low relative to the degree of spatiotemporal variability. Such "binned" fields typically also lack a quantitative measure of uncertainty. Geostatistical mapping has previously been shown to make higher spatiotemporal resolution maps possible, and also provides a measure uncertainty associated with the gridded products. This study proposes a flexible moving window block kriging method that can be used as a tool for creating high spatiotemporal resolution maps from satellite data. It relies only on the assumption that the observed physical quantity exhibits spatial correlation that can be inferred from the observations. The method has several innovations relative to previously applied methods: (1) it provides flexibility in the spatial resolution of the contiguous maps, (2) it is applicable for physical quantities with varying spatiotemporal coverage (i.e., density of measurements) by utilizing a more general and versatile data sampling approach, and (3) it provides rigorous assessments of the uncertainty associated with the gridded products. The method is demonstrated by creating Level 3 products from observations of column-integrated carbon dioxide (XCO2) from the GOSAT (Greenhouse Gases Observing Satellite) satellite, and solar induced fluorescence (SIF) from the GOME-2 (Global Ozone Monitoring Experiment-2) instrument.

  13. 78 FR 14920 - Earth Stations Aboard Aircraft Communicating With Fixed-Satellite Service Geostationary-Orbit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... COMMISSION 47 CFR Parts 2 and 25 Earth Stations Aboard Aircraft Communicating With Fixed-Satellite Service... technical and licensing rules for Earth Stations Aboard Aircraft (ESAA), i.e., earth stations on aircraft...-11.2 GHz, 11.45-11.7 GHz, 11.7-12.2 GHz (space-to-Earth or downlink) and 14.0-14.5 GHz...

  14. Earth Resources Technology Satellite: US standard catalog No. U-12

    NASA Technical Reports Server (NTRS)

    1973-01-01

    To provide dissemination of information regarding the availability of Earth Resources Technology Satellite (ERTS) imagery, a U.S. Standard Catalog is published on a monthly schedule. The catalogs identify imagery which has been processed and input to the data files during the preceding month. The U.S. Standard Catalog includes imagery covering the Continental United States, Alaska, and Hawaii. As a supplement to these catalogs, an inventory of ERTS imagery on 16 millimeter microfilm is available. The catalogs consist of four parts: (1) annotated maps which graphically depict the geographic areas covered by the imagery listed in the current catalog, (2) a computer-generated listing organized by observation identification number (D) with pertinent information on each image, (3) a computer listing of observations organized by longitude and latitude, and (4) observations which have had changes made in their catalog information since the original entry in the data base.

  15. A Comparison of Techniques for Scheduling Earth-Observing Satellites

    NASA Technical Reports Server (NTRS)

    Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

    2004-01-01

    Scheduling observations by coordinated fleets of Earth Observing Satellites (EOS) involves large search spaces, complex constraints and poorly understood bottlenecks, conditions where evolutionary and related algorithms are often effective. However, there are many such algorithms and the best one to use is not clear. Here we compare multiple variants of the genetic algorithm: stochastic hill climbing, simulated annealing, squeaky wheel optimization and iterated sampling on ten realistically-sized EOS scheduling problems. Schedules are represented by a permutation (non-temperal ordering) of the observation requests. A simple deterministic scheduler assigns times and resources to each observation request in the order indicated by the permutation, discarding those that violate the constraints created by previously scheduled observations. Simulated annealing performs best. Random mutation outperform a more 'intelligent' mutator. Furthermore, the best mutator, by a small margin, was a novel approach we call temperature dependent random sampling that makes large changes in the early stages of evolution and smaller changes towards the end of search.

  16. Spacecraft design project: Low Earth orbit communications satellite

    NASA Technical Reports Server (NTRS)

    Moroney, Dave; Lashbrook, Dave; Mckibben, Barry; Gardener, Nigel; Rivers, Thane; Nottingham, Greg; Golden, Bill; Barfield, Bill; Bruening, Joe; Wood, Dave

    1991-01-01

    This is the final product of the spacecraft design project completed to fulfill the academic requirements of the Spacecraft Design and Integration 2 course (AE-4871) taught at the U.S. Naval Postgraduate School. The Spacecraft Design and Integration 2 course is intended to provide students detailed design experience in selection and design of both satellite system and subsystem components, and their location and integration into a final spacecraft configuration. The design team pursued a design to support a Low Earth Orbiting (LEO) communications system (GLOBALSTAR) currently under development by the Loral Cellular Systems Corporation. Each of the 14 team members was assigned both primary and secondary duties in program management or system design. Hardware selection, spacecraft component design, analysis, and integration were accomplished within the constraints imposed by the 11 week academic schedule and the available design facilities.

  17. Interactive analysis of a large aperture Earth observations satellite

    NASA Technical Reports Server (NTRS)

    Wright, R. L.; Deryder, D. D.; Ferebee, M. J., Jr.; Smith, J. C.

    1983-01-01

    A system level design and analysis has been conducted on an Earth Observation Satellite (EOS) system using the Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) computer-aided design and analysis program. The IDEAS program consists of about 40 user-friendly technical modules and an interactive graphics display. The reflector support system and feed mast of the EOS spacecraft are constructed with box-truss structural concept, a lattice configuration which can be packaged for delivery in a single Shuttle flight and deployed in orbit. The deployed spacecraft consists of a 120-m by 60-m parabolic focal axis. The spacecraft was modeled for structural, thermal, and control systems analysis and structural elements were designed. On-orbit dynamic and thermal loading analyses were conducted; spacecraft weights and developmental and first unit costs were determined.

  18. Tropospheric emission spectrometer for the Earth Observing System's Aura satellite.

    PubMed

    Beer, R; Glavich, T A; Rider, D M

    2001-05-20

    The Tropospheric Emission Spectrometer (TES) is an imaging infrared Fourier-transform spectrometer scheduled to be launched into polar Sun-synchronous orbit aboard the Earth Observing System's Aura satellite in June 2003. The primary objective of the TES is to make global three-dimensional measurements of tropospheric ozone and of the physical-chemical factors that control its formation, destruction, and distribution. Such an ambitious goal requires a highly sophisticated cryogenic instrument operating over a wide frequency range, which, in turn, demands state-of-the-art infrared detector arrays. In addition, the measurements require an instrument that can operate in both nadir and limb-sounding modes with a precision pointing system. The way in which these mission objectives flow down to the specific science and measurement requirements and in turn are implemented in the flight hardware are described. A brief overview of the data analysis approach is provided.

  19. Earth observations satellite data policy: Process and outcome

    SciTech Connect

    Shaffer, L.R.

    1994-12-31

    The National Aeronautics and Space Administration (NASA) develops, launches, and operates satellites to observe and monitor the Earth and its environment. This study categorizes each program based on the relationship between NASA and external organizations. A program can be an autonomous mission undertaken for NASA`s own constituency, or it can involve a client agency or a partner. These relationships affect how data policy decisions are made and implemented, and how the valuable output of NASA`s Earth observations satellites is managed. The process in NASA for determining which programs will be approved is very informal. Ideas and concepts surface and reach the consciousness of NASA management; if sufficient support is achieved, a proposal can move to the feasibility study phase and from there become an approved and funded mission. The handling of data can be an important consideration in generating political support for program approval. Autonomous programs tend to have decisions made at lower levels and documented informally or not at all. Data policy is part of routine implementation of programs and does not generally rise to the visibility of the agency head or congressional staff or the Executive Office of the President. Responsibility for data management for autonomous missions is retained at NASA centers. Client programs involve higher level decision makers, and are the subject of political interest because they cross agency boundaries. The data policy process includes presidential statements on data access. As part of the client relationship, NASA often provides resources to the client for data handling and analysis, and shares these responsibilities. Data policy for partner programs is the result of bargaining between the partners, either foreign government agencies or private companies.

  20. A high-fidelity satellite ephemeris program for Earth satellites in eccentric orbits

    NASA Technical Reports Server (NTRS)

    Simmons, David R.

    1990-01-01

    A program for mission planning called the Analytic Satellite Ephemeris Program (ASEP), produces projected data for orbits that remain fairly close to the Earth. ASEP does not take into account lunar and solar perturbations. These perturbations are accounted for in another program called GRAVE, which incorporates more flexible means of input for initial data, provides additional kinds of output information, and makes use of structural programming techniques to make the program more understandable and reliable. GRAVE was revised, and a new program called ORBIT was developed. It is divided into three major phases: initialization, integration, and output. Results of the program development are presented.

  1. Earth Science Mission Benefits of High Data Rate Satellite Communications

    NASA Astrophysics Data System (ADS)

    Jackson, J. M.; Munger, J.; Emch, P. G.; Sen, B.; Gu, D.

    2013-12-01

    Satellite to ground communication bandwidth limitations place constraints on current earth remote sensing instruments which limit the spatial and spectral resolution of data transmitted to the ground for processing. Instruments such as VIIRS, CrIS and OMPS on the Soumi-NPP spacecraft must aggregate data both spatially and spectrally in order to fit inside current data rate constraints limiting the optimal use of the as-built sensors. Future planned missions such as PACE, TEMPO and DESDynI Radar will have to trade spatial and spectral resolution if increased communication band width is not made available. A number of high-impact, environmental remote sensing disciplines such as hurricane observation, mega-city air quality, wild fire detection and monitoring, and monitoring of coastal oceans would benefit dramatically from enabling the downlinking of sensor data at higher spatial and spectral resolutions. The enabling technologies of multi-Gbps Ka-Band communication and multi-Terabit SSRs are currently available with high technological maturity enabling high data volume mission requirements to be met with minimal mission constraints while utilizing only a very few ground sites from NASA's Near Earth Network (NEN). These enabling technologies will be described in detail with emphasis on benefits to future remote sensing missions currently under consideration by government agencies.

  2. Algorthms and prigrams complex for chaotic dynamics investigation of the Earth artificial sat-ellites. (Russian Title: Комплекс алгоритмов и программ для исследования хаотичности в динамике искусственных спутников Земли )

    NASA Astrophysics Data System (ADS)

    Bordovitsyna, T. V.; Aleksandrova, A. G.; Chuvashov, I. N.

    2010-12-01

    In this paper complex of algorithms and programs for revelation and investigation of dynamical chaotic state in the motion of the Earth artificial satellites by parallel computing is presented. Complex has been based on the program "Numerical model of the system artificial satellites motion" for cluster "Skiff Cyberia". Factor MEGNO as main indicator of chaotic state has been used. The factor is computed by combined numerical integration of equations of the motion, equations in variation and equations of MEGNO parameters. The results of program complex testing in the problem of MEGNO parameters calculation for different types of geostationary orbits are presented.

  3. A photovoltaic power system and a low-power satellite earth station for Indonesia

    NASA Technical Reports Server (NTRS)

    Delombard, Richard; Everson, Kent

    1985-01-01

    A photovoltaic power system and a low-power, two-way satellite earth station have been installed at Wawotobi, Sulawesi, Indonesia to provide university classroom communications for audio teleconferencing and video graphics. This project is a part of the Agency for International Development's Rural Satellite Program. The purpose of this program is to demonstrate the use of satellite communications for development assistance applications. The purpose of the photovoltaic power system is to demonstrate the suitability of a hybrid photovoltaic/engine-generator power system for a remote satellite earth station. This paper describes the design, installation and initial operation of the photovoltaic power system and the earth station.

  4. Photovoltaic power system for satellite Earth stations in remote areas: Project status and design description

    NASA Technical Reports Server (NTRS)

    Delombard, R.

    1984-01-01

    A photovoltaic power system which will be installed at a remote location in Indonesia to provide power for a satellite Earth station and a classroom for video and audio teleconferences are described. The Earth station may also provide telephone service to a nearby village. The use of satellite communications for development assistance applications and the suitability of a hybrid photovoltaic engine generator power system for remote satellite Earth stations are demonstrated. The Indonesian rural satellite project is discussed and the photovoltaic power system is described.

  5. A photovoltaic power system and a low-power satellite earth station for Indonesia

    NASA Astrophysics Data System (ADS)

    Delombard, Richard; Everson, Kent

    A photovoltaic power system and a low-power, two-way satellite earth station have been installed at Wawotobi, Sulawesi, Indonesia to provide university classroom communications for audio teleconferencing and video graphics. This project is a part of the Agency for International Development's Rural Satellite Program. The purpose of this program is to demonstrate the use of satellite communications for development assistance applications. The purpose of the photovoltaic power system is to demonstrate the suitability of a hybrid photovoltaic/engine-generator power system for a remote satellite earth station. This paper describes the design, installation and initial operation of the photovoltaic power system and the earth station.

  6. Satellite Mapping of the Earth's Ozone and Sulfur Dioxide

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin; Bhartia, P. K.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The Total Ozone Mapping Spectrometer (TOMS) instruments are spatially-scanning UV spectrometers that have produced daily global images of total ozone over the last 21 years since the launch of the Nimbus 7 satellite. The instruments use a total ozone retrieval algorithm pioneered by J.V. Dave and C. L. Mateer for the Nimbus 4 Backscatter Ultraviolet (BUV) instrument, designed by D.F. Heath. The TOMS ozone maps have revealed the relations between total ozone and atmospheric dynamics, and shown the dramatic losses of ozone in the Antarctic ozone hole and the Northern hemisphere. The accepted long-term trends in global, regional, and local ozone are derived from data from the Nimbus 7 TOMS and three successive TOMS flights on Russian, Japanese, and American satellites. The next TOMS flight will be launched in 2000. The contiguous mapping design and fortuitous choice of TOMS wavelengths bands also permitted imaging of a second atmospheric gas, sulfur dioxide, which is transient due to its short lifetime. The importance of this measurement was first realized after the eruption of El Chichon volcano in 1982. The extreme range of sizes of volcanic eruptions and the associated danger require observations from a distant observing platform. The first quantitative time series of the input of sulfur dioxide by explosive volcanic eruptions into the atmosphere thus was developed from the TOMS missions. Finally, the Rayleigh and aerosol scattering spectral characteristic and reflectivity complete the four dominant pieces of information in the near UV albedo of the Earth. The four parameters are derived with a linear algorithm, the absorption coefficients of the gases, and effective paths computed from radiative transfer tables. Absorbing aerosol clouds (smoke, dust, volcanic ash) are readily identified by their deviation from a Rayleigh signature. The greatest shortcoming of the TOMS dataset is the 24 hour time resolution that is produced by the polar orbit of the satellite

  7. Satellite Mapping of the Earth's Ozone and Sulfur Dioxide

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin; Bhartia, P. K.

    2000-01-01

    The Total Ozone Mapping Spectrometer (TOMS) instruments are spatially-scanning UV spectrometers that have produced daily global images of total ozone over the last 21 years since the launch of the Nimbus 7 satellite. The instruments use a total ozone retrieval algorithm pioneered by J.V. Dave and C. L. Mateer for the Nimbus 4 Backscatter Ultraviolet (BUV) instrument, designed by D.F. Heath. The TOMS ozone maps have revealed the relations between total ozone and atmospheric dynamics, and shown the dramatic losses of ozone in the Antarctic ozone hole and the Northern hemisphere. The accepted long-term trends in global, regional, and local ozone are derived from data from the Nimbus 7 TOMS and three successive TOMS flights on Russian, Japanese, and American satellites. The next TOMS flight will be launched in 2000. The contiguous mapping design and fortuitous choice of TOMS wavelengths bands also permitted imaging of a second atmospheric gas, sulfur dioxide, which is transient due to its short lifetime. The importance of this measurement was first realized after the eruption of El Chichon volcano in 1982. The extreme range of sizes of volcanic eruptions and the 'associated danger require observations from a distant observing platform. The first quantitative time series of the input of sulfur dioxide by explosive volcanic eruptions into the atmosphere thus was developed from the TOMS missions. Finally, the Rayleigh and aerosol scattering spectral characteristic and reflectivity complete the four dominant pieces of information in the near UV albedo of the Earth. The four parameters are derived with a linear algorithm, the absorption coefficients of the gases, and effective paths computed from radiative transfer tables. Absorbing aerosol clouds (smoke, dust, volcanic ash) are readily identified by their deviation from a Rayleigh signature. The greatest shortcoming of the TOMS dataset is the 24 hour time resolution that is produced by the polar orbit of the satellite

  8. How Long Does It Take for a Satellite to Fall to Earth?

    ERIC Educational Resources Information Center

    Lira, Antonio

    2015-01-01

    The purpose of this paper is to introduce students of science and engineering to the orbital lifetimes of satellites in circular low Earth orbits. It is only necessary to know about classical mechanics for this calculation. The orbital decay of satellites is due to the interaction of the satellite with the surrounding gas, atmospheric drag.…

  9. Influence of satellite motion on polarization qubits in a Space-Earth quantum communication link.

    PubMed

    Bonato, Cristian; Aspelmeyer, Markus; Jennewein, Thomas; Pernechele, Claudio; Villoresi, Paolo; Zeilinger, Anton

    2006-10-16

    In a Space quantum-cryptography experiment a satellite pointing system is needed to send single photons emitted by the source on the satellite to the polarization analysis apparatus on Earth. In this paper a simulation is presented regarding how the satellite pointing systems affect the polarization state of the single photons, to help designing a proper compensation system.

  10. Three-Dimensional Orbits of Earth Satellites, Including Effects of Earth Oblateness and Atmospheric Rotation

    NASA Technical Reports Server (NTRS)

    Nielsen, Jack N.; Goodwin, Frederick K.; Mersman, William A.

    1958-01-01

    The principal purpose of the present paper is to present sets of equations which may be used for calculating complete trajectories of earth satellites from outer space to the ground under the influence of air drag and gravity, including oblateness effects, and to apply these to several examples of entry trajectories starting from a circular orbit. Equations of motion, based on an "instantaneous ellipse" technique, with polar angle as independent variable, were found suitable for automatic computation of orbits in which the trajectory consists of a number of revolutions. This method is suitable as long as the trajectory does not become nearly vertical. In the terminal phase of the trajectories, which are nearly vertical, equations of motion in spherical polar coordinates with time as the independent variable were found to be more suitable. In the first illustrative example the effects of the oblateness component of the earth's gravitational field and of atmospheric rotation were studied for equatorial orbits. The satellites were launched into circular orbits at a height of 120 miles, an altitude sufficiently high that a number of revolutions could be studied. The importance of the oblateness component of the earth's gravitational field is shown by the fact that a satellite launched at circular orbital speed, neglecting oblateness, has a perigee some 67,000 feet lower when oblateness forces are included in the equations of motion than when they are not included. Also, the loss in altitude per revolution is double that of a satellite following an orbit not subject to oblateness. The effect of atmospheric rotation on the loss of altitude per revolution was small. As might be surmised, the regression of the line of nodes as predicted by celestial mechanics is unchanged when drag is included. It is clear that the inclination of the orbital plane to the equator will be relatively unaffected by drag for no atmospheric rotation since the drag lies in the orbital plane in

  11. Timation 3 satellite. [artificial satellite for navigation, space radiation, and time transfer applications

    NASA Technical Reports Server (NTRS)

    Bartholomew, C. A.

    1972-01-01

    The characteristics of the Timation 3 satellite are discussed. A diagram of the basic structure is provide to show the solar panels, navigation and telemetry antennas, gravity gradient booms, and solar cell experiments. The specific application of the satellite for time management or time transfer for navigation purposes is reported. Various measurements and experiments conducted by the satellite are described.

  12. History of satellite missions and measurements of the Earth Radiation Budget (1957-1984)

    NASA Technical Reports Server (NTRS)

    House, F. B.; Gruber, A.; Hunt, G. E.; Mecherikunnel, A. T.

    1986-01-01

    The history of satellite missions and their measurements of the earth radiation budget from the beginning of the space age until the present time are reviewed. The survey emphasizes the early struggle to develop instrument systems to monitor reflected shortwave and emitted long-wave exitances from the earth, and the problems associated with the interpretation of these observations from space. In some instances, valuable data sets were developed from satellite measurements whose instruments were not specifically designed for earth radiation budget observations.

  13. 78 FR 14952 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... COMMISSION 47 CFR Part 2 Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service... of Earth Stations Aboard Aircraft (ESAA) in the 14.0-14.5 GHz band from secondary to primary and... stations of the FSS on a primary basis in the 11.7-12.2 GHz band (space-to-Earth), on an unprotected...

  14. On the Long Period Luni-Solar Effect in the Motion of an Artificial Satellite

    NASA Technical Reports Server (NTRS)

    Musen, Peter

    1961-01-01

    Two systems of formulas are presented for the determination of the long period perturbations caused by the Sun and the Moon in the motion of an artificial satellite. The first system can be used to determine the lunar effect for all satellites. The second method is more convenient for finding the lunar effect for close satellites and the solar effect for all satellites. Knowledge of these effects is essential for determining the stability of the satellite orbit. The basic equations of both systems are arranged in a form which permits the use of numerical integration. The two theories are more accurate and more adaptable to the use of electronic machines than the analytical developments obtained previously.

  15. Survey of United States commercial satellites in geosynchronous Earth orbit

    NASA Astrophysics Data System (ADS)

    Hunt, Lawerence D.; Miller, Jeffrey L.

    1994-09-01

    This thesis examines the domestic commercial satellite options available for telecommunication and remote sensing services. The study provides a single source, comprehensive examination of the available commercial U.S. geosynchronous telecommunications satellites as well as the remote sensing spacecraft which may be utilized for commercial purposes. A general satellite communications technology overview is provided as background material for the more detailed satellite compendium. The following telecommunications operators are included with their respective domestic communications satellites: Alascom, Alpha Lyracom Pan American, AT&T, Comsat, GE Americom, GTE Spacenet, Hughes and Intelsat. Satellite evolution, overview, key design features, and performance parameters are catalogued. Additionally, each satellite's communications payload is examined in detail. Emerging technologies in the remote sensing field are presented. The current GOES and NOAA satellite systems are surveyed with an emphasis on each satellite's capabilities and operational status.

  16. Satellite co-locations as a link between SLR, GPS and Low Earth Orbiting (LEO) satellites

    NASA Astrophysics Data System (ADS)

    Melachroinos, S. A.; Lemoine, F. G.; Chinn, D. S.; Nicolas, J. B.; Zelensky, N. P.; Wimert, J.; Radway, Y.

    2013-12-01

    The procedure applied for the determination of the International Terrestrial Reference Frame (ITRF) requires the combination of all four major techniques of Space Geodesy. This combination is only possibly realized by the introduction of the local-ties between co-located techniques. A local-tie is the lever arm vector between the marker points on the sites where two or more space geodesy instruments operate. The local ties are used as additional observations with proper variances. They are usually derived from local surveys using either classical geodesy or the global navigation satellite systems (GNSS). The Global Positioning System (GPS) plays a major role in the ITRF combination by linking together all the other three techniques SLR, DORIS and VLBI (Altamimi and Collilieux 2009). However, discrepancies between local ties and space geodesy estimates are well known although the reasons for these discrepancies are often not clear. These discrepancies could be either due to errors in local ties and in coordinate estimates or in both. In this study, we use the tracking to G05-35 and G06-36 and one LEO by SLR sites and their combined orbits, earth rotation parameters (ERPs) and station positions in order to establish space-based co-location ties on the stations. The LEO satellite used in this experiment is Jason-2, which carries both GPS and SLR. Therefore from the data-processing point of view the LEO satellite is used as a fast moving station (Thaller et al. 2011). Jason-2 is also equipped with DORIS, but it will be included into another combined analysis. Subsequently, we compare the consistency of our space-based co-locations to the ones from ITRF08 and SLRF08 - IGb08 solutions.

  17. Total Ozone Mapping Spectrometer (TOMS) Derived Data, Global Earth Coverage (GEC) from NASA's Earth Probe Satellite

    DOE Data Explorer

    This is data from an external datastream processed through the ARM External Data Center (XDC) at Brookhaven National Laboratory. The XDC identifies sources and acquires data, called "external data", to augment the data being generated within the ARM program. The external data acquired are usually converted from native format to either netCDF or HDF formats. The GEC collection contains global data derived from the Total Ozone Mapping Spectrometer (TOMS) instrument on the Earth Probe satellite, consisting of daily values of aerosol index, ozone and reflectivity remapped into a regular 1x1.25 deg grid. Data are available from July 25, 1996 - December 31, 2005, but have been updated or replaced as of September 2007. See the explanation on the ARM web site at http://www.arm.gov/xds/static/toms.stm and the information at the NASA/TOMS web site: http://toms.gsfc.nasa.gov/ (Registration required)

  18. Earth and Ocean Physics Applications Program /EOPAP/. [NASA program using satellite observation

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.

    1973-01-01

    Abbreviated description of the objectives, experiments, spacecraft, and required schedules of a proposed NASA program blending geophysics, oceanography, and space technology in order to facilitate the prediction of earthquakes, storm surges, tidal waves, and the condition of ocean surfaces. Relevant measurements from space will be carried out by LAGEOS, SAESATS-1, GEOPAUSE, GRAVSAT, and SEASATS-2 satellites contributing data on earth dynamics, sea surface states, satellite dynamics, and earth gravity. The development of suitable mathematical models for predicting events on earth on the basis of satellite data is considered.

  19. Earth-satellite-Earth laser long-path absorption experiment using the Retroreflector in Space (RIS) on the Advanced Earth Observing Satellite (ADEOS)

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Koga, Nobuhiko; Matsui, Ichiro; Sasano, Yasuhiro; Minato, Atsushi; Ozawa, Kenichi; Saito, Yasunori; Nomura, Akio; Aoki, Tetsuo; Itabe, Toshikazu; Kunimori, Hiroo; Murata, Isao; Fukunishi, Hiroshi

    1999-03-01

    This paper reports the results of the laser long-path absorption experiments carried out with the Retroreflector in Space (RIS) on the Advanced Earth Observing Satellite (ADEOS). The RIS is a 0.5 m diameter single-element hollow retroreflector with a unique optical design which uses a curved mirror surface to correct velocity aberrations caused by the satellite movement. In the RIS experiments a laser beam was transmitted from a ground station, reflected by the RIS, and received back at the ground station. The absorption of the intervening atmosphere was measured in the round-trip optical path. After the launch of the ADEOS in August 1996, the optical characteristics of the RIS were tested, and it was confirmed that the RIS worked well in orbit. The spectroscopic measurement was carried out with the single-longitudinal-mode TEA 1464-4258/1/2/015/img12 lasers by means of the method utilizing the Doppler shift of the reflected beam caused by the movement of the satellite. The spectrum of ozone was successfully measured in the 1464-4258/1/2/015/img13 region, and the measurement of the column contents of ozone was validated with the simultaneous heterodyne spectrometer measurement. In June 1997, however, the experiment with the RIS was discontinued due to the malfunction of the ADEOS solar paddle.

  20. Present status and future plans of the Japanese earth observation satellite program

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Kiyoshi; Arai, Kohei; Igarashi, Tamotsu

    Japan is now operating 3 earth observation satellites, i. e. MOS-1 (Marine Observation Satellite-1, Momo-1 in Japanese), EGS (Experimental Geodetic Satellite, Ajisai in Japanese) and GMS (Geostationary Meteorological Satellite, Himawari in Japanese). MOS-1 has 3 different sensors, MESSR (Multispectral Electronic Self Scanning Radiometer), VTIR (Visible and Thermal Infrared Radiometer) and MSR (Microwave Scanning Radiometer) in addition to DCS (Data Collection System). GMS has two sensors, VISSR (Visible and IR Spin Scan Radiometer) and SEM (Solar Environmental Monitor). EGS is equipped with reflecting mirrors of the sun light and laser reflecters. For the future earth observation satellites, ERS-1 (Earth Resources Satellite-1), MOS-1b, ADEOS (Advanced Earth Observing Satellite) are under development. Two sensors, AMSR (Advanced Microwave Scanning Radiometer) and ITIR (Intermediate Thermal IR Radiometer) for NASA's polar platform are initial stage of development. Study and planning are made for future earth observation satellites including Japanese polor platform, TRMM, etc.). The study for the second generation GMS has been made by the Committee on the Function of Future GMS under the request of Japan Meteorological Agency in FY 1987.

  1. Earth-satellite propagation above GHz: Papers from the 1972 spring URSI session on experiments utilizing the ATS-5 satellite

    NASA Technical Reports Server (NTRS)

    Ippolito, L. J. (Compiler)

    1972-01-01

    Papers are reported from the Special Session on Earth-Satellite Propagation Above 10 GHz, presented at The 1972 Spring Meeting of the United States National Committee, International Union of Radio Science, April 1972, Washington, D. C. This session was devoted to propagation measurements associated with the Applications Technology Satellite (ATS-5), which provided the first operational earth-space links at frequencies above 15 GHz. A comprehensive summary is presented of the major results of the ATS-5 experiment measurements and related radiometric, radar and meteorological studies. The papers are organized around seven selected areas of interest, with the results of the various investigators combined into a single paper presented by a principal author for that area. A comprehensive report is provided on the results of the ATS-5 satellite to earth transmissions. A complete list of published reports and presentations related to the ATS-5 Millimeter Wave Experiment is included.

  2. Design of a Representative Low Earth Orbit Satellite to Improve Existing Debris Models

    NASA Technical Reports Server (NTRS)

    Clark, S.; Dietrich, A.; Werremeyer, M.; Fitz-Coy, N.; Liou, J.-C.

    2012-01-01

    This paper summarizes the process and methodologies used in the design of a small-satellite, DebriSat, that represents materials and construction methods used in modern day Low Earth Orbit (LEO) satellites. This satellite will be used in a future hypervelocity impact test with the overall purpose to investigate the physical characteristics of modern LEO satellites after an on-orbit collision. The major ground-based satellite impact experiment used by DoD and NASA in their development of satellite breakup models was conducted in 1992. The target used for that experiment was a Navy Transit satellite (40 cm, 35 kg) fabricated in the 1960 s. Modern satellites are very different in materials and construction techniques from a satellite built 40 years ago. Therefore, there is a need to conduct a similar experiment using a modern target satellite to improve the fidelity of the satellite breakup models. The design of DebriSat will focus on designing and building a next-generation satellite to more accurately portray modern satellites. The design of DebriSat included a comprehensive study of historical LEO satellite designs and missions within the past 15 years for satellites ranging from 10 kg to 5000 kg. This study identified modern trends in hardware, material, and construction practices utilized in recent LEO missions, and helped direct the design of DebriSat.

  3. A comparative study of spherical and flat-Earth geopotential modeling at satellite elevations

    NASA Technical Reports Server (NTRS)

    Parrott, M. H.; Hinze, W. J.; Braile, L. W.

    1985-01-01

    Flat-Earth and spherical-Earth geopotential modeling of crustal anomaly sources at satellite elevations are compared by computing gravity and scalar magnetic anomalies perpendicular to the strike of variably dimensioned rectangular prisms at altitudes of 150, 300, and 450 km. Results indicate that the error caused by the flat-Earth approximation is less than 10% in most geometric conditions. Generally, error increase with larger and wider anomaly sources at higher altitudes. For most crustal source modeling applications at conventional satellite altitudes, flat-Earth modeling can be justified and is numerically efficient.

  4. Jupiter and Planet Earth. [planetary and biological evolution and natural satellites

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The evolution of Jupiter and Earth are discussed along with their atmospheres, the radiation belts around both planets, natural satellites, the evolution of life, and the Pioneer 10. Educational study projects are also included.

  5. Tropospheric Emission Spectrometer (TES) for the Earth Observing System (EOS) CHEM Satellite

    NASA Technical Reports Server (NTRS)

    Beer, R.; Glavich, T.; Rider, D.

    2000-01-01

    The Tropospheric Emission Spectrometer (TES) is an imaging infrared Fourier transform spectrometer scheduled to be launched into polar sun-synchronous orbit on the Earth Observing System (EOS) CHEM satellite in December 2002.

  6. Study of effects of space power satellites on life support functions of the earth's magnetosphere

    NASA Technical Reports Server (NTRS)

    Douglas, M.; Laquey, R.; Deforest, S. E.; Lindsey, C.; Warshaw, H.

    1977-01-01

    The effects of the Satellite Solar Power System (SSPS) on the life support functions of the earth's magnetosphere were investigated. Topics considered include: (1) thruster effluent effects on the magnetosphere; (2) biological consequences of SSPS reflected light; (3) impact on earth bound astronomy; (4) catastrophic failure and debris; (5) satellite induced processes; and (6) microwave power transmission. Several impacts are identified and recommendations for further studies are provided.

  7. Outline of the survey on the development of earth observation satellites

    NASA Technical Reports Server (NTRS)

    1977-01-01

    An independent earth observation system with land and sea satellites to be developed by Japan is described. Visible and infrared radiometers, microwave radiometers, microwave scattermeters, synthetic aperture radar, and laser sensors are among the instrumentation discussed. Triaxial attitude control, basic technology common to sea and land observation satellites as well as land data analytical technology developed for U.S. LANDSAT data are reviewed.

  8. An autonomous navigation algorithm for high orbit satellite using star sensor and ultraviolet earth sensor.

    PubMed

    Baohua, Li; Wenjie, Lai; Yun, Chen; Zongming, Liu

    2013-01-01

    An autonomous navigation algorithm using the sensor that integrated the star sensor (FOV1) and ultraviolet earth sensor (FOV2) is presented. The star images are sampled by FOV1, and the ultraviolet earth images are sampled by the FOV2. The star identification algorithm and star tracking algorithm are executed at FOV1. Then, the optical axis direction of FOV1 at J2000.0 coordinate system is calculated. The ultraviolet image of earth is sampled by FOV2. The center vector of earth at FOV2 coordinate system is calculated with the coordinates of ultraviolet earth. The autonomous navigation data of satellite are calculated by integrated sensor with the optical axis direction of FOV1 and the center vector of earth from FOV2. The position accuracy of the autonomous navigation for satellite is improved from 1000 meters to 300 meters. And the velocity accuracy of the autonomous navigation for satellite is improved from 100 m/s to 20 m/s. At the same time, the period sine errors of the autonomous navigation for satellite are eliminated. The autonomous navigation for satellite with a sensor that integrated ultraviolet earth sensor and star sensor is well robust.

  9. Demonstrating Circular Motion with a Model Satellite/Earth System

    ERIC Educational Resources Information Center

    Whittaker, Jeff

    2008-01-01

    A number of interesting demonstrations of circular and satellite motion have been described in this journal. This paper presents a variation of a centripetal force apparatus found in G.D. Freier and F.J. Anderson's "A Demonstration Handbook for Physics," which has been modified in order to demonstrate both centripetal force and satellite motion.…

  10. The 2011 Draconid Shower Risk to Earth-Orbiting Satellites

    NASA Technical Reports Server (NTRS)

    Cooke, William J.; Moser, Danielle E.

    2010-01-01

    Current meteor shower forecast models project a strong Draconid outburst, possibly a storm, on October 8, 2011, with a duration of approximately 7 hours and peaking between 19 and 21 hours UT. Predicted rates span an order of magnitude, with maximum Zenithal Hourly Rates (ZHRs) ranging from a few tens to several hundred. Calibration of the NASA MSFC Meteoroid Stream Model 1 to radar and optical observations of past apparitions, particularly the 2005 Draconid outburst 2, suggest that the maximum rate will be several hundreds per hour. Given the high spatial density of the Draconid stream, this implies a maximum meteoroid flux of 5-10 Draconids km(exp -2)/hr (to a limiting diameter of 1 mm), some 25-50 times greater than the normal sporadic flux of 0.2 km(exp -2)/ hr for particles of this size. Total outburst fluence, assuming a maximum ZHR of 750, is 15.5 Draconids km(exp -2), resulting in an overall 10x risk increase to spacecraft surfaces vulnerable to hypervelocity impacts by 1 mm particles. It is now established that a significant fraction of spacecraft anomalies produced by shower meteoroids (e.g. OLYMPUS and LandSat 5) are caused by electrostatic discharges produced by meteoroid impacts. In these cases, the charge generated is roughly proportional to v(exp 3.5(4)), giving a Draconid moving at 20 km/s approximately 1/80th the electrical damage potential of a Leonid of the same mass. In other words, a Draconid outburst with a maximum ZHR of 800 presents the same electrical risk as a normal Leonid shower with a ZHR of 15, assuming the mass indices and shower durations are the same. This is supported by the fact that no spacecraft electrical anomalies were reported during the strong Draconid outbursts of 1985 and 1998. However, the lack of past anomalies should not be taken as carte blanche for satellite operators to ignore the 2011 Draconids, as the upcoming outburst will constitute a period of enhanced risk for vehicles in near-Earth space. Each spacecrft is

  11. Computer programs for plotting spot-beam coverages from an earth synchronous satellite and earth-station antenna elevation angle contours

    NASA Technical Reports Server (NTRS)

    Stagl, T. W.; Singh, J. P.

    1972-01-01

    A description and listings of computer programs for plotting geographical and political features of the world or a specified portion of it, for plotting spot-beam coverages from an earth-synchronous satellite over the computer generated mass, and for plotting polar perspective views of the earth and earth-station antenna elevation contours for a given satellite location are presented. The programs have been prepared in connection with a project on Application of Communication Satellites to Educational Development.

  12. Battery Performance of ADEOS (Advanced Earth Observing Satellite) and Ground Simulation Test Results

    NASA Technical Reports Server (NTRS)

    Koga, K.; Suzuki, Y.; Kuwajima, S.; Kusawake, H.

    1997-01-01

    The Advanced Earth Observing Satellite (ADEOS) is developed with the aim of establishment of platform technology for future spacecraft and inter-orbit communication technology for the transmission of earth observation data. ADEOS uses 5 batteries, consists of two packs. This paper describes, using graphs and tables, the ground simulation tests and results that are carried to determine the performance of the ADEOS batteries.

  13. Clouds and the Earth's Radiant Energy System (CERES) Visualization Single Satellite Footprint (SSF) Plot Generator

    NASA Technical Reports Server (NTRS)

    Barsi, Julia A.

    1995-01-01

    The first Clouds and the Earth's Radiant Energy System (CERES) instrument will be launched in 1997 to collect data on the Earth's radiation budget. The data retrieved from the satellite will be processed through twelve subsystems. The Single Satellite Footprint (SSF) plot generator software was written to assist scientists in the early stages of CERES data analysis, producing two-dimensional plots of the footprint radiation and cloud data generated by one of the subsystems. Until the satellite is launched, however, software developers need verification tools to check their code. This plot generator will aid programmers by geolocating algorithm result on a global map.

  14. Spacecraft systems design trade-offs for the Earth Resources Technology Satellite.

    NASA Technical Reports Server (NTRS)

    Branchflower, G. A.

    1973-01-01

    The Earth Resources Technology Satellite Program's use of flight proven hardware in the design of a satellite for earth sensor payload support and data handling is discussed. The use of an existing satellite as the building block around which additional support systems such as the orbit adjust system, the redundant wideband telemetry systems, the second regulated power system, and the quad redundant command system is analyzed. System performance seen in orbit vs design objectives are discussed to point up the success of the design approach chosen. Also discussed are the schedule and cost benefits derived from the use of previously developed hardware with additional subsystems as required to meet program requirements.

  15. Comparison of low-Earth-orbit satellite attitude controllers submitted to controllability constraints

    NASA Astrophysics Data System (ADS)

    Steyn, Willem H.

    1994-07-01

    A rule-based fuzzy controller is presented and compared with an adaptive MIMO LQR controller in a low-earth-orbit small satellite attitude control system. The attitude is passively gravity gradient stabilized and actively three-axis magnetorquer controlled. This method insures an earth-pointing satellite making use of a nondepletable and nonmechanical means of control. A realistic simulation environment, using a nonlinear satellite dynamic model with linear attitude estimators plus sensor measurement noise and external disturbance torques, was used to evaluate the different control techniques.

  16. Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 3: Low-cost Earth observation with minimal satellite swath

    NASA Astrophysics Data System (ADS)

    Razoumny, Yury N.

    2016-12-01

    Continuing the series of papers with description of the fundamentals of the Route Theory for satellite constellation design, the general method for minimization of the satellite swath width required under given constraint on the maximum revisit time (MRT), the main quality characteristic of the satellite constellation discontinuous coverage, is presented. The interrelation between MRT and multiplicity of the periodic coverage - the minimum number of the observation sessions realized for the points of observation region during the satellite tracks' repetition period - is revealed and described. In particular, it is shown that a change of MRT can occur only at points of coverage multiplicity changing. Basic elements of multifold Earth coverage theory are presented and used for obtaining analytical relations for the minimum swath width providing given multifold coverage. The satellite swath width calculation procedure for the multifold coverage of rotating Earth using the iterations on the sphere of stationary coverage is developed. The numerical results for discontinuous coverage with minimal satellite swath, including comparison with some known particular cases and implementations of the method, are presented.

  17. Collision frequency of artificial satellites - The creation of a debris belt

    NASA Technical Reports Server (NTRS)

    Kessler, D. J.; Cour-Palais, B. G.

    1978-01-01

    The probability of satellite collisions increases with the number of satellites. In the present paper, possible time scales for the growth of a debris belt from collision fragments are determined, and possible consequences of continued unrestrained launch activities are examined. Use is made of techniques formerly developed for studying the evolution (growth) of the asteroid belt. A model describing the flux from the known earth-orbiting satellites is developed, and the results from this model are extrapolated in time to predict the collision frequency between satellites. Hypervelocity impact phenomena are then examined to predict the debris flux resulting from collisions. The results are applied to design requirements for three types of future space missions.

  18. Satellite Derived Earth Surface Temperatures: a Crop Assessment Tool.

    NASA Astrophysics Data System (ADS)

    Crosiar, Christy Lynn

    The data for this research consist of the following: 23 days of NOAA/AVHRR satellite data; AgRISTARS enumerator data (or ground truth data) for 26 counties in three midwestern states (Iowa, Nebraska and North Dakota) and radiosonde observations for nine upper air stations, producing an 8 state coverage. The objectives of this research are threefold: (1) to develop a regression model to estimate maximum shelter temperature, (2) to develop a method to assess crop conditions and (3) to determine the variability within a scan line due to changes in optical depth and/or scan angle. The regression model uses three independent variables derived from satellite data to predict maximum shelter temperature. The first independent variable is the satellite's first estimate of temperature, the channel 4 effective temperature. The second independent variable is the difference in the amount of radiation received by the satellite's two thermal channels (4 and 5) serving as a measure of the water vapor in the atmosphere. The third independent variable, path length, uses the pixel position within the scan line to calculate the viewing angle from nadir. This approach resulted in a good R^2 of.65. Three reasons to explain why this R ^2 is not stronger are as follows: (1) a known temperature difference between satellite and shelter temperature, (2) unregistered satellite data--the latitude and longitude of the satellite data are not the location of the shelter and (3) comparison of an area averaged temperature (satellite data) to a point source (shelter) measurement are two different values. The second objective is using satellite data, during the heading and flowering period, combined with the ground truth data or the enumerator data obtained through the AgRISTARS program to determine crop stress. Using two regression models, two satellite temperature indices are used as predictors of a ratio in yield. Statistically significant relationships exist for soybeans and sunflowers. The third

  19. An introduction to orbit dynamics and its application to satellite-based earth monitoring systems

    NASA Technical Reports Server (NTRS)

    Brooks, D. R.

    1977-01-01

    The long term behavior of satellites is studied at a level of complexity suitable for the initial planning phases of earth monitoring missions. First-order perturbation theory is used to describe in detail the basic orbit dynamics of satellite motion around the earth and relative to the sun. Surface coverage capabilities of satellite orbits are examined. Several examples of simulated observation and monitoring missions are given to illustrate representative applications of the theory. The examples stress the need for devising ways of maximizing total mission output in order to make the best possible use of the resultant data base as input to those large-scale, long-term earth monitoring activities which can best justify the use of satellite systems.

  20. Computer and Voice Network Management Through Low Earth Orbiting Satellites

    DTIC Science & Technology

    2006-03-01

    26 2. Miniaturized Node and Mobile Access ............................................26 a. Iridium...26 B. SYSTEM MODELS OF FIXED AND MOBILE GROUND STATIONS...31 3. Mobile APRS and AX.25 Satellite Ground Station ........................32 4. Iridium Sensor Station

  1. Satellite Emission Radio Interferometric Earth Surveying (SERIES). [astrometry

    NASA Technical Reports Server (NTRS)

    Macdoran, P. F.

    1980-01-01

    Existing satellite radio emissions of the global positioning system were exploited as a resource for cost effective high accuracy geodetic measurements. System applications were directed toward crustal dynamics and earthquake research.

  2. Relative motion characteristics of 2 near-Earth Satellites

    NASA Technical Reports Server (NTRS)

    Schutz, B. E.

    1984-01-01

    The stability of the nonlinear dynamical system of two GRAVSAT - type satellites was investigated by performing several numerical experiments which provide the simulations of the relative motion characteristics between the two satellites for various specified time intervals. The simulations included the relative range, range-rate, and relative acceleration magnitude. These simulations were generated with respect to appropriate initial orbital elements which were obtained such that the instantaneous separation distance between the two satellites has small fluctuations from a specified constant separation distance. The simulation results indicate that the behavior of the relative motions is very sensitive to the initial orbital elements of the satellites and that for a specified time interval of interest. A stable behavior is possible only with the use of an appropriate set of initial orbital elements compatible with the gravity field used to derive them.

  3. Design and analysis of a mode B and mode JD satellite Earth station

    NASA Astrophysics Data System (ADS)

    Hance, Dennis J.

    1994-06-01

    This thesis focuses on the design, integration, and analysis of an amateur radio service mode B and mode JD satellite earth station. Preliminary designs were investigated to determine the optimum configuration for the earth station. Modern digital modems, cabling structures, an 80386-based computer system, satellite tracking software, transmission and reception antennas, preamplifiers, and sophisticated performance measurement technologies were integrated into a functioning earth station. Initially, component availability and station design dictated the selection and acquisition of the requisite station equipment, integration of the transmitter, receiver preamplifiers, antennas, and computer equipment followed. Preliminary testing of the various components in the integration station occupied a significant amount of time. Empirical test tracking of different amateur and commercial satellites verified proper operation of the earth station. Results are discussed throughout this thesis.

  4. Survey of United States Commercial Satellites in Geosynchronous Earth Orbit

    DTIC Science & Technology

    1994-09-01

    stationkeeping maneuvers. Heat pipes have replaced heat spreaders on the north and south faces of the body, where the communications subsystem is mounted. This...Orbit 6. AUTHOR(S) Lawrence D. Hunt and Jeffrey L. Miller 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING Naval Postgraduate School...Satellite evolution, overview, key design features, and performance parameters are catalogued. Additionally, each satellite’s communications payload

  5. A study on artificial rare earth (RE2O3) based neutron absorber.

    PubMed

    Kim, Kyung-O; Kim, Jong Kyung

    2015-11-01

    A new concept of a neutron absorption material (i.e., an artificial rare earth compound) was introduced for criticality control in a spent fuel storage system. In particular, spent nuclear fuels were considered as a potential source of rare earth elements because the nuclear fission of uranium produces a full range of nuclides. It was also found that an artificial rare earth compound (RE2O3) as a High-Level Waste (HLW) was naturally extracted from pyroprocessing technology developed for recovering uranium and transuranic elements (TRU) from spent fuels. In this study, various characteristics (e.g., activity, neutron absorption cross-section) were analyzed for validating the application possibility of this waste compound as a neutron absorption material. As a result, the artificial rare earth compound had a higher neutron absorption probability in the entire energy range, and it can be used for maintaining sub-criticality for more than 40 years on the basis of the neutron absorption capability of Boral™. Therefore, this approach is expected to vastly improve the efficiency of radioactive waste management by simultaneously keeping HLW and spent nuclear fuel in a restricted space.

  6. Surveys of the earth's resources and environment by satellites

    NASA Technical Reports Server (NTRS)

    Nordberg, W.; Tiedemann, H.; Bohn, C.

    1975-01-01

    The potential and promise of observing the earth from the vantage point of space is discussed. The systematic surveying of processes and phenomena occurring on the surface of the earth by Landsat 1 and Nimbus 5 is considered to be useful in the following areas: assessment of water resources; mineral and petroleum exploration; land use planning; crop, forest, and rangeland inventory; assessment of flood, earthquake, and other environmental hazards; monitoring coastal processes; environmental effects of industrial effluents and of air pollution; mapping the distribution and types of ice covering the earth's polar caps and global soil moisture distributions.

  7. Scheduler for monitoring objects orbiting earth using satellite-based telescopes

    DOEpatents

    Olivier, Scot S; Pertica, Alexander J; Riot, Vincent J; De Vries, Willem H; Bauman, Brian J; Nikolaev, Sergei; Henderson, John R; Phillion, Donald W

    2015-04-28

    An ephemeris refinement system includes satellites with imaging devices in earth orbit to make observations of space-based objects ("target objects") and a ground-based controller that controls the scheduling of the satellites to make the observations of the target objects and refines orbital models of the target objects. The ground-based controller determines when the target objects of interest will be near enough to a satellite for that satellite to collect an image of the target object based on an initial orbital model for the target objects. The ground-based controller directs the schedules to be uploaded to the satellites, and the satellites make observations as scheduled and download the observations to the ground-based controller. The ground-based controller then refines the initial orbital models of the target objects based on the locations of the target objects that are derived from the observations.

  8. Cost reductions through earth resource satellites in developed countries

    NASA Technical Reports Server (NTRS)

    Schweickart, R. L.; Buffalano, A. C.

    1975-01-01

    Data from detailed studies on the possible economic impact of the use of remote sensing technology in industry and agriculture are presented and analyzed. The utility of satellite surveillance in reduction of crop production forecast error, recognition and monitoring of crop diseases and insect infestations, and range management is evaluated. Application of satellite maps to facilitate land resource decisions, mineral exploration, geological studies, and water resource inventories is considered, as is the usefulness of early storm warning in the reduction of property damage. The cost of remote sensing is compared to that of conventional methods whenever possible.

  9. Wave propagation and earth satellite radio emission studies

    NASA Technical Reports Server (NTRS)

    Yeh, K. C.; Liu, C. H.; Flaherty, B. J.

    1974-01-01

    Radio propagation studies of the ionosphere using satellite radio beacons are described. The ionosphere is known as a dispersive, inhomogeneous, irregular and sometimes even nonlinear medium. After traversing through the ionosphere the radio signal bears signatures of these characteristics. A study of these signatures will be helpful in two areas: (1) It will assist in learning the behavior of the medium, in this case the ionosphere. (2) It will provide information of the kind of signal characteristics and statistics to be expected for communication and navigational satellite systems that use the similar geometry.

  10. Small Satellite Constellations: The Future for Operational Earth Observation

    NASA Technical Reports Server (NTRS)

    Stephens, J. Paul

    2007-01-01

    Nanosat, microsat and minisat are low-cost, rapid-response small-satellites built from advanced terrestrial technology. SSTL delivers the benefits of affordable access to space through low-cost, rapid response, small satellites designed and built with state-of-the-art COTS technologies by: a) reducing the cost of entry into space; b) Achieving more missions within fixed budgets; c) making constellations and formation flying financially viable; d) responding rapidly from initial concept to orbital operation; and e) bringing the latest industrial COTS component advances to space. Growth has been stimulated in constellations for high temporal revisit&persistent monitoring and military responsive space assets.

  11. Pulse strobing in VLBI for observation of geostationary earth satellites.

    NASA Astrophysics Data System (ADS)

    Gorodetskij, V. M.

    The possibility of broadband synthesis by pulse strobing for observation of slow-moving objects using standard MARK-1 VLBI processing methods is discussed. The possibility of increasing the SNR by using a special type of pulse function is indicated. A specific scheme for application of the method in satellite radiointerferometry is examined.

  12. The microwave noise environment at a geostationary satellite caused by the brightness of the earth

    NASA Technical Reports Server (NTRS)

    Smith, E. K.; Njoku, E. G.

    1985-01-01

    The microwave antenna temperature due to the earth in the satellite antenna beam has been computed for a series of longitudes for a satellite in geostationary orbit and for frequencies of 1 to 50 GHz. An earth-coverage beam is assumed for simplicity, but the technique is applicable to arbitrary beam shapes. Detailed calculations have been performed to account for varying land-ocean fractions within the field of view. Emission characteristics of the earth's atmosphere and surface are used with an accurate radiation transfer program to compute observed brightness temperatures. The value of 290 K commonly used for antenna temperature in satellite communication noise calculations is overly conservative, with more realistic values lying in the 60 to 240 K range.

  13. The Study of Effects of Time Variations in the Earth's Gravity Field on Geodetic Satellites

    NASA Technical Reports Server (NTRS)

    Shum, C. K.

    1998-01-01

    The temporal variations in the Earth's gravity field are the consequences of complex interactions between atmosphere, ocean, solid Earth, hydrosphere and cryosphere. The signal ranges from several hours to 18.6 years to geological time scale. The direct and indirect consequences of these variations are manifested in such phenomena as changes in the global sea level and in the global climate pattern. These signals produce observable geodetic satellites. The primary objectives of the proposed effects on near-Earth orbiting investigation include (1) the improved determination of the time-varying gravity field parameters (scale from a few hour to 18.6 year and secular) using long-term satellite laser rs ranging (SLR) observations to multiple geodetic satellites, and (2) the enhanced understanding of these variations with their associated meteorological and geophysical consequences.

  14. Design description report for a photovoltaic power system for a remote satellite earth terminal

    NASA Technical Reports Server (NTRS)

    Marshall, N. A.; Naff, G. J.

    1987-01-01

    A photovoltaic (PV) power system has been installed as an adjunct to an agricultural school at Wawatobi on the large northern island of the Republic of Indonesia. Its purpose is to provide power for a satellite earth station and a classroom. The renewable energy developed supports the video and audio teleconferencing systems as well as the facility at large. The ground station may later be used to provide telephone service. The installation was made in support of the Agency for International Development's Rural Satellite Program, whose purpose is to demonstrate the use of satellite communications for rural development assistance applications. The objective of this particular PV power system is to demonstrate the suitability of a hybrid PV engine-generator configuration for remote satellite earth stations.

  15. Applications of neural network methods to the processing of earth observation satellite data.

    PubMed

    Loyola, Diego G

    2006-03-01

    The new generation of earth observation satellites carries advanced sensors that will gather very precise data for studying the Earth system and global climate. This paper shows that neural network methods can be successfully used for solving forward and inverse remote sensing problems, providing both accurate and fast solutions. Two examples of multi-neural network systems for the determination of cloud properties and for the retrieval of total columns of ozone using satellite data are presented. The developed algorithms based on multi-neural network are currently being used for the operational processing of European atmospheric satellite sensors and will play a key role in related satellite missions planed for the near future.

  16. Magsat: A satellite for measuring near earth magnetic fields

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Regan, R. D.; Murphy, J. P.

    1977-01-01

    Magsat, designed for making measurements of the geomagnetic vector field, is evaluated. For accurate vector measurements the attitude of the fluxgate magnetometer will be determined to about 15 arc-seconds. Expected measurement accuracy will be 6 (gamma) in each component and 3 in magnitude. The Magsat data will be applied to solid earth studies including modeling of the Earth's main magnetic field, delineation of regional magnetic anomalies of crustal origin, and interpretation of those anomalies in terms of geologic and geophysical models. An opportunity will be presented to the scientific community to participate in data use investigations.

  17. Earth Observatory Satellite system definition study. Report no. 3: Design/cost tradeoff studies

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The key issues in the Earth Observatory Satellite (EOS) program which are subject to configuration study and tradeoff are identified. The issue of a combined operational and research and development program is considered. It is stated that cost and spacecraft weight are the key design variables and design options are proposed in terms of these parameters. A cost analysis of the EOS program is provided. Diagrams of the satellite configuration and subsystem components are included.

  18. On identifying the specular reflection of sunlight in earth-monitoring satellite data.

    SciTech Connect

    Nelsen, James M., Jr.; Hohlfelder, Robert James; Jackson, Dale Clayton; Longenbaugh, Randolph S.

    2009-03-01

    Among the background signals commonly seen by Earth-monitoring satellites is the specular reflection of sunlight off of Earth's surface, commonly referred to as a glint. This phenomenon, involving liquid or ice surfaces, can result in the brief, intense illumination of satellite sensors appearing from the satellite perspective to be of terrestrial origin. These glints are important background signals to be able to identify with confidence, particularly in the context of analyzing data from satellites monitoring for transient surface or atmospheric events. Here we describe methods for identifying glints based on the physical processes involved in their production, including spectral fitting and polarization measurements. We then describe a tool that, using the WGS84 spheroidal Earth model, finds the latitude and longitude on Earth where a reflection of this type could be produced, given input Sun and satellite coordinates. This tool enables the user to determine if the surface at the solution latitude and longitude is in fact reflective, thus identifying the sensor response as a true glint or an event requiring further analysis.

  19. Mini-satellite exploration of very near earth space fuel objects

    SciTech Connect

    Zuppero, A.C.; Jacox, M.G.

    1992-09-19

    A prospecting plan is presented to assay near Earth objects (NEO) for their potential to yield rocket fuel. The plan calls out small satellites as the near-term means to achieve low cost surveys and deep subsurface sampling of NEO composition. The water bearing classes of NEO to be considered are limited to those accessible in short time and with small thrusters. These include the water bearing clay objects (phylosilicates) at nearly trivial distances from Earth, and the recently identified water ice objects such as comet ([number sign]4015) 1979 VA. These objects are evaluated as small satellite prospecting and assay vehicle targets.

  20. Mini-satellite exploration of very near earth space fuel objects

    SciTech Connect

    Zuppero, A.C.; Jacox, M.G.

    1992-09-19

    A prospecting plan is presented to assay near Earth objects (NEO) for their potential to yield rocket fuel. The plan calls out small satellites as the near-term means to achieve low cost surveys and deep subsurface sampling of NEO composition. The water bearing classes of NEO to be considered are limited to those accessible in short time and with small thrusters. These include the water bearing clay objects (phylosilicates) at nearly trivial distances from Earth, and the recently identified water ice objects such as comet ({number_sign}4015) 1979 VA. These objects are evaluated as small satellite prospecting and assay vehicle targets.

  1. The Earth's gravity field from satellite geodesy: A 30 year adventure

    NASA Astrophysics Data System (ADS)

    Rapp, Richard H.

    1991-12-01

    The history of research in the Earth's gravity field from satellite geodesy is described and limitations of existing geopotential models are indicated. Although current solutions have made outstanding achievements, their limited accuracy restricts their use for some oceanographic applications. An example is discussed where there appears to be an incompatibility of the long wavelength geoid undulation obtained through satellite analysis with independent estimates that have become available. The future Aristoteles mission is seen as providing a significant leap in Earth gravity field knowledge improvement.

  2. Improvement of the Earth's gravity field from terrestrial and satellite data

    NASA Technical Reports Server (NTRS)

    Rapp, Richard H.

    1992-01-01

    The determination of the Earth's gravitational potential can be done through the analysis of satellite perturbations, the analysis of surface gravity data, or both. The combination of the two data types yields a solution that combines the strength of each method: the longer wavelength strength in the satellite analysis with the better high frequency information from surface gravity data. Since 1972, Ohio State has carried out activities that have provided surface gravity data to a number of organizations who have developed combination potential coefficient models that describe the Earth's gravitational potential.

  3. Analysis of a Perturbation Solution of the Main Problem in Artificial Satellite Theory

    DTIC Science & Technology

    1990-09-01

    NAVAL POSTGRADUATE SCHOOL Monterey, California "".NrM DTic N~ ELECTE 𔃻 OCT 3 1991 jVSTArZS 4 CJADXU’J THESIS ANALYSIS OF A PERTURBATION SOLUTION OF...THE MAIN PROBLEM IN ARTIFICIAL SATELLITE TH’IEORY by Scott David Krambeck September 1990 Thesis Advisor Donald A. Danielson Approved for public...Date of Report (year, month, day) 15 Page Count Engneer’s Thesis From To September 1990 142 16 Supplementary Notation The views expressed in this

  4. The equations of motion of an artificial satellite in nonsingular variables

    NASA Technical Reports Server (NTRS)

    Giacaglia, G. E. O.

    1975-01-01

    The equations of motion of an artificial satellite are given in nonsingular variables. Any term in the geopotential is considered as well as luni-solar perturbations up to an arbitrary power of r/r prime; r prime being the geocentric distance of the disturbing body. Resonances with tesseral harmonics and with the moon or sun are also considered. By neglecting the shadow effect, the disturbing function for solar radiation is also developed in nonsingular variables for the long periodic perturbations. Formulas are developed for implementation of the theory in actual computations.

  5. The equations of motion of an artificial satellite in nonsingular variables

    NASA Technical Reports Server (NTRS)

    Giacaglia, G. E. O.

    1977-01-01

    The equations of motion of an artificial satellite are given in nonsingular variables. Any term in the geopotential is considered as well as luni-solar perturbations up to an arbitrary power of r/r', r' being the geocentric distance of the disturbing body. Resonances with tesseral harmonics and with the moon or sun are also considered. By neglecting the shadow effect, the disturbing function for solar radiation is also developed in nonsingular variables for the long periodic perturbations. Formulas are developed for implementation of the theory in actual computations.

  6. Recursive analytical solution describing artificial satellite motion perturbed by an arbitrary number of zonal terms

    NASA Technical Reports Server (NTRS)

    Mueller, A. C.

    1977-01-01

    An analytical first order solution has been developed which describes the motion of an artificial satellite perturbed by an arbitrary number of zonal harmonics of the geopotential. A set of recursive relations for the solution, which was deduced from recursive relations of the geopotential, was derived. The method of solution is based on Von-Zeipel's technique applied to a canonical set of two-body elements in the extended phase space which incorporates the true anomaly as a canonical element. The elements are of Poincare type, that is, they are regular for vanishing eccentricities and inclinations. Numerical results show that this solution is accurate to within a few meters after 500 revolutions.

  7. The masses of Uranus and its major satellites from Voyager tracking data and earth-based Uranian satellite data

    NASA Astrophysics Data System (ADS)

    Jacobson, R. A.; Campbell, J. K.; Taylor, A. H.; Synnott, S. P.

    1992-06-01

    Improved values for the masses of the Uranian system and the satellites Ariel, Umbriel, Titania, Oberon, and Miranda are obtained on the basis of an analysis of the Doppler-tracking data and star-satellite imaging from the Voyager 2 spacecraft combined with earth-based astrometric satellite observations. Masses are expressed as the product, the universal gravitational constant times the mass of the body, in units of (cu km/sq s). The satellite masses are (4.4 +/- 0.5) for Miranda, (90.3 +/- 8.0) for Ariel, (78.2 +/- 9.0) for Umbriel, (235.3 +/- 6.0) for Titania, and (201.1 +/- 5.0) for Oberon. Quoted errors are standard errors and are the present assessment of the true rather than the formal errors. The Uranus rotational pole orientation angles and gravity harmonic coefficients were fixed at the values determined by French et al. (1988) from stellar occultations of the Uranian rings observed from both the earth and Voyager 2 and from the occultation of the spacecraft radio signal.

  8. The masses of Uranus and its major satellites from Voyager tracking data and earth-based Uranian satellite data

    NASA Technical Reports Server (NTRS)

    Jacobson, R. A.; Campbell, J. K.; Taylor, A. H.; Synnott, S. P.

    1992-01-01

    Improved values for the masses of the Uranian system and the satellites Ariel, Umbriel, Titania, Oberon, and Miranda are obtained on the basis of an analysis of the Doppler-tracking data and star-satellite imaging from the Voyager 2 spacecraft combined with earth-based astrometric satellite observations. Masses are expressed as the product, the universal gravitational constant times the mass of the body, in units of (cu km/sq s). The satellite masses are (4.4 +/- 0.5) for Miranda, (90.3 +/- 8.0) for Ariel, (78.2 +/- 9.0) for Umbriel, (235.3 +/- 6.0) for Titania, and (201.1 +/- 5.0) for Oberon. Quoted errors are standard errors and are the present assessment of the true rather than the formal errors. The Uranus rotational pole orientation angles and gravity harmonic coefficients were fixed at the values determined by French et al. (1988) from stellar occultations of the Uranian rings observed from both the earth and Voyager 2 and from the occultation of the spacecraft radio signal.

  9. A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation

    ERIC Educational Resources Information Center

    Wee, Loo Kang; Goh, Giam Hwee

    2013-01-01

    We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…

  10. Design of volume hologram filters for suppression of daytime sky brightness in artificial satellite detection.

    PubMed

    Gao, Hanhong; Watson, Jonathan M; Stuart, Joseph Scott; Barbastathis, George

    2013-03-11

    We present a design methodology for volume hologram filters (VHFs) with telephoto objectives to improve contrast of solar-illuminated artificial satellites observed with a ground-based optical telescope and camera system operating in daytime. VHFs provide the ability to selectively suppress incoming light based on the range to the source, and are used to suppress the daylight background noise since signal (satellite) and noise (daylight scatterers) are located at different altitudes. We derive the overall signal-to-noise ratio (SNR) enhancement as the system metric, and balance main design parameters over two key performance considerations--daylight attenuation and spectral bandwidth--to optimize the functioning of VHFs. Overall SNR enhancement of 7.5 has been achieved. Usage of multi-pixel cameras can potentially further refine this system.

  11. Study on Orbital Decay of Near Earth Satellites with KS Orthogonal Elements

    NASA Astrophysics Data System (ADS)

    Ps, Sandeep

    STUDY ON ORBITAL DECAY OF NEAR EARTH SATELLITES WITH KS ORTHOGONAL ELEMENTS SANDEEP P S The knowledge of satellite orbit decay and its expected life prior to launch is necessary for mission planning purpose. Several sets of data for various parametric studies is sought quite often, it is necessary to minimize computational time involved for generating decay predictions, keeping the prediction accuracy normally good. A number of factors play dominant role in perturbation modelling for near earth satellites such as oblateness of the Earth, presence of the atmosphere, luni-solar attraction and solar radiation pressure. This paper concerns with the study of orbital decay of near earth satellites with KS orthogonal elements, which provide accurate orbit predictions at low computational time. Perturbations considered are due to oblateness of the Earth and the atmospheric drag. The Earth’s zonal harmonic terms J2 to J6 are included and the drag is modeled with an analytical diurnally oblate atmosphere. Effect of Earth’s geomagnetic and solar activity is included in density and density scale height computations. JACCHIA77 atmospheric model is utilized. The developed software is validated with the orbital data of decayed objects taken from www.space-track.org.

  12. Determination of Azimuth Angle at Burnout for Placing a Satellite Over a Selected Earth Position

    NASA Technical Reports Server (NTRS)

    Skopinski, T. H.; Johnson, Katherine G.

    1960-01-01

    Expressions are presented for relating the satellite position in the orbital plane with the projected latitude and longitude on a rotating earth surface. An expression is also presented for determining the azimuth angle at a given burnout position on the basis of a selected passage position on the earth's surface. Examples are presented of a satellite launched eastward and one launched westward, each passing over a selected position sometime after having completed three orbits. Incremental changes from the desired latitude and longitude due to the earth's oblateness are included in the iteration for obtaining the azimuth angles of the two examples. The results for both cases are then compared with those obtained from a computing program using an oblate rotating earth. Changes from the selected latitude and longitude resulting from incremental changes from the burn-out azimuth angle and latitude are also analyzed.

  13. Alpha-satellite DNA and vector composition influence rates of human artificial chromosome formation.

    PubMed

    Grimes, Brenda R; Rhoades, Angela A; Willard, Huntington F

    2002-06-01

    Human artificial chromosomes (HACs) have been proposed as a new class of potential gene transfer and gene therapy vector. HACs can be formed when bacterial cloning vectors containing alpha-satellite DNA are transfected into cultured human cells. We have compared the HAC-forming potential of different sequences to identify features critical to the efficiency of the process. Chromosome 17 or 21 alpha-satellite arrays are highly competent HAC-forming substrates in this assay. In contrast, a Y-chromosome-derived alpha-satellite sequence is inefficient, suggesting that centromere specification is at least partly dependent on DNA sequence. The length of the input array is also an important determinant, as reduction of the chromosome-17-based array from 80 kb to 35 kb reduced the frequency of HAC formation. In addition to the alpha-satellite component, vector composition also influenced HAC formation rates, size, and copy number. The data presented here have a significant impact on the design of future HAC vectors that have potential to be developed for therapeutic applications and as tools for investigating human chromosome structure and function.

  14. Spaceborne observations of a changing Earth - Contribution from ESÁ s operating and approved satellite missions.

    NASA Astrophysics Data System (ADS)

    Johannessen, J. A.

    2009-04-01

    The overall vision for ESÁs Earth Observation activities is to play a central role in developing the global capability to understand planet Earth, predict changes, and mitigate negative effects of global change on its populations. Since Earth observation from space first became possible more than forty years ago, it has become central to monitoring and understanding how the dynamics of the Earth System work. The greatest progress has been in meteorology, where space-based observations have become indispensable, but it is now also progressively penetrating many of the fields making up Earth sciences. Exploiting Earth observation from space presents major multidisciplinary challenges to the researches working in the Earth sciences, to the technologists who build the state-of-the-art sensors, and to the scientists interpreting measurements made of processes occurring on or within the Earth's surface and in its atmosphere. The scientific community has shown considerable imagination in rising to these challenges, and in exploiting the latest technological developments to measure from space the complex processes and interactions that occur in the Earth System. In parallel, there has been significant progress in developing computer models that represent the many processes that make up the Earth System, and the interactions and feedback between them. Success in developing this holistic view is inextricably linked to the data provided by Earth Observation systems. Satellites provide the fundamental, consistent, regular and global measurements needed to drive, parameterise, test and improve those Earth System models. These developments, together with changes in society's awareness of the need for information on a changing world, have repetitively supported the decisions on how ESA can best focus its resources, and those of the European community that it serves, in order to address critical issues in Earth System science. Moreover, it is a fact that many operational

  15. Reducing Formation-Keeping Maneuver Costs for Formation Flying Satellites in Low-Earth Orbit

    NASA Technical Reports Server (NTRS)

    Hamilton, Nicholas

    2001-01-01

    Several techniques are used to synthesize the formation-keeping control law for a three-satellite formation in low-earth orbit. The objective is to minimize maneuver cost and position tracking error. Initial reductions are found for a one-satellite case by tuning the state-weighting matrix within the linear-quadratic-Gaussian framework. Further savings come from adjusting the maneuver interval. Scenarios examined include cases with and without process noise. These results are then applied to a three-satellite formation. For both the one-satellite and three-satellite cases, increasing the maneuver interval yields a decrease in maneuver cost and an increase in position tracking error. A maneuver interval of 8-10 minutes provides a good trade-off between maneuver cost and position tracking error. An analysis of the closed-loop poles with respect to varying maneuver intervals explains the effectiveness of the chosen maneuver interval.

  16. The Smithsonian Earth Physics Satellite (SEPS) definition study, volumes 1 through 4

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A limited Phase B study was undertaken to determine the merit and feasibility of launching a proposed earth physics satellite with Apollo-type hardware. The study revealed that it would be feasible to launch this satellite using a S-IB stage, a S-IVB with restart capability, an instrument unit, a SLA for the satellite shroud, and a nose cone (AS-204 configuration). A definition of the proposed satellite is provided, which is specifically designed to satisfy the fundamental requirement of providing an orbiting benchmark of maximum accuracy. The satellite is a completely passive, solid 3628-kg sphere of 38.1-cm radius and very high mass-to-area ratio (7980 kg sq mi). In the suggested orbit of 55 degrees inclination, 3720 km altitude, and low eccentricity, the orbital lifetime is extremely long, so many decades of operation can be expected.

  17. Satellite-tracking and Earth dynamics research programs

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Arequipa station obtained a total of 31,989 quick-look range observations on 719 passes in the six months. Data were acquired from Metsahovi, San Fernando, Kootwijk, Wettzell, Grasse, Simosato, Graz, Dodaira and Herstmonceux. Work progressed on the setup of SAO 1. Discussions were also initiated with the Israelis on the relocation of SAO-3 to a site in southern Israel in FY-1984. Arequipa and the cooperating stations continued to track LAGEOS at highest priority for polar motion and Earth rotation studies, and for other geophysical investigations, including crustal dynamics, earth and ocean tides, and the general development of precision orbit determination. SAO completed the revisions to its field software as a part of its recent upgrading program. With cesium standards Omega receivers, and other timekeeping aids, the station was able to maintain a timing accuracy of better than plus or minus 6 to 8 microseconds.

  18. Satellite on-board processing for earth resources data

    NASA Technical Reports Server (NTRS)

    Bodenheimer, R. E.; Gonzalez, R. C.; Gupta, J. N.; Hwang, K.; Rochelle, R. W.; Wilson, J. B.; Wintz, P. A.

    1975-01-01

    Results of a survey of earth resources user applications and their data requirements, earth resources multispectral scanner sensor technology, and preprocessing algorithms for correcting the sensor outputs and for data bulk reduction are presented along with a candidate data format. Computational requirements required to implement the data analysis algorithms are included along with a review of computer architectures and organizations. Computer architectures capable of handling the algorithm computational requirements are suggested and the environmental effects of an on-board processor discussed. By relating performance parameters to the system requirements of each of the user requirements the feasibility of on-board processing is determined for each user. A tradeoff analysis is performed to determine the sensitivity of results to each of the system parameters. Significant results and conclusions are discussed, and recommendations are presented.

  19. Systems definition summary. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A standard spacecraft bus for performing a variety of earth orbit missions in the late 1970's and 1980's is defined. Emphasis is placed on a low-cost, multimission capability, benefitting from the space shuttle system. The subjects considered are as follows: (1) performance requirements, (2) internal interfaces, (3) redundancy and reliability, (4) communications and data handling module design, (5) payload data handling, (6) application of the modular design to various missions, and (7) the verification concept.

  20. Satellite on-board processing for earth resources data

    NASA Technical Reports Server (NTRS)

    Bodenheimer, R. E.; Gonzalez, R. C.; Gupta, J. N.; Hwang, K.; Rochelle, R. W.; Wilson, J. B.; Wintz, P. A.

    1975-01-01

    The feasibility was investigated of an on-board earth resources data processor launched during the 1980-1990 time frame. Projected user applications were studied to define the data formats and the information extraction algorithms that the processor must execute. Based on these constraints, and the constraints imposed by the available technology, on-board processor systems were designed and their feasibility evaluated. Conclusions and recommendations are given.

  1. Online Resource for Earth-Observing Satellite Sensor Calibration

    NASA Technical Reports Server (NTRS)

    McCorkel, J.; Czapla-Myers, J.; Thome, K.; Wenny, B.

    2015-01-01

    The Radiometric Calibration Test Site (RadCaTS) at Railroad Valley Playa, Nevada is being developed by the University of Arizona to enable improved accuracy and consistency for airborne and satellite sensor calibration. Primary instrumentation at the site consists of ground-viewing radiometers, a sun photometer, and a meteorological station. Measurements made by these instruments are used to calculate surface reflectance, atmospheric properties and a prediction for top-of-atmosphere reflectance and radiance. This work will leverage research for RadCaTS, and describe the requirements for an online database, associated data formats and quality control, and processing levels.

  2. Design Concepts for a Small Space-Based GEO Relay Satellite for Missions Between Low Earth and near Earth Orbits

    NASA Technical Reports Server (NTRS)

    Bhasin, Kul B.; Warner, Joseph D.; Oleson, Steven; Schier, James

    2014-01-01

    The main purpose of the Small Space-Based Geosynchronous Earth orbiting (GEO) satellite is to provide a space link to the user mission spacecraft for relaying data through ground networks to user Mission Control Centers. The Small Space Based Satellite (SSBS) will provide services comparable to those of a NASA Tracking Data Relay Satellite (TDRS) for the same type of links. The SSBS services will keep the user burden the same or lower than for TDRS and will support the same or higher data rates than those currently supported by TDRS. At present, TDRSS provides links and coverage below GEO; however, SSBS links and coverage capability to above GEO missions are being considered for the future, especially for Human Space Flight Missions (HSF). There is also a rising need for the capability to support high data rate links (exceeding 1 Gbps) for imaging applications. The communication payload on the SSBS will provide S/Ka-band single access links to the mission and a Ku-band link to the ground, with an optical communication payload as an option. To design the communication payload, various link budgets were analyzed and many possible operational scenarios examined. To reduce user burden, using a larger-sized antenna than is currently in use by TDRS was considered. Because of the SSBS design size, it was found that a SpaceX Falcon 9 rocket could deliver three SSBSs to GEO. This will greatly reduce the launch costs per satellite. Using electric propulsion was also evaluated versus using chemical propulsion; the power system size and time to orbit for various power systems were also considered. This paper will describe how the SSBS will meet future service requirements, concept of operations, and the design to meet NASA users' needs for below and above GEO missions. These users' needs not only address the observational mission requirements but also possible HSF missions to the year 2030. We will provide the trade-off analysis of the communication payload design in terms of

  3. NASA satellite to study earth's oceans from space. [Seasat-A satellite

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The feasibility of using microwave instruments to scan the world's oceans from space in order to obtain scientific data for oceanographers, meteorologists, and commercial users of the seas will be demonstrated during the mission of the Seasat A satellite which will be launched into an 800 kilometer high near circular orbit by an Agena Atlas-Agena launch vehicle. The satellite configuration, its payload, and data collection and processing capabilities are described as well as the launch vehicle system.

  4. Low Earth orbit satellite attitude control by fractional control laws

    NASA Astrophysics Data System (ADS)

    Kailil, A.; Mrani, N.; Abid, M.; Touati, M. Mliha; Choukri, S.; Elalami, N.

    2004-11-01

    Dans cet article, le controle d'attitude trois-axes d'un satellite par roues de reaction est etabli par les methodes fractionnaires. Dans le but d'expliquer les avantages de ces methodes, une etude comparative a etablie entre la methode lineaire quadratique (LQR) et la methode fractionnaire (FOC). Le but de cette etude est de realiser une loi de controle efficace satisfaisant des specifications donnees, et maintenant la stabilite et les performances requises meme en presence des incertitudes sur les parametres intrinsiques du systeme et sous l'effet des perturbations externes. Mots-cles : controle fractionnaire ; controle d'attitude trois-axes ; roues de reaction ; systeme quasi-bilineaire ; controle optimal. Abstract Fractional order control (FOC) methods are applied to the three-axis reaction wheels satellite attitude control. In order to show the advantages of this method, a comparative study between a Linear Quadratic Regulator (LQR) and a FOC is established through two principal fractional control laws. The aim of this paper is to establish an efficient control law which satisfies a given specifications, and maintains sufficient stability and accuracy even under the strong effects of intrinsic parameters uncertainties, and also external perturbations. Keywords: fractional control; 3-axis attitude control; reaction wheels; quasi-bilinear system; optimal control

  5. Estimating the Earth's gravity field using a multi-satellite SLR solution

    NASA Astrophysics Data System (ADS)

    Bloßfeld, Mathis; Stefka, Vojtech; Müller, Horst; Gerstl, Michael

    2013-04-01

    Satellite Laser Ranging (SLR) is the unique technique to determine station coordinates, Earth Orientation Parameter (EOP) and Stokes coefficients of the Earth's gravity field in one common adjustment. These parameters form the so called "three pillars" (Plag & Pearlman, 2009) of the Global Geodetic Observing System (GGOS). In its function as official analysis center of the International Laser Ranging Service (ILRS), DGFI is developing and maintaining software to process SLR observations called "DGFI Orbit and Geodetic parameter estimation Software" (DOGS). The software is used to analyze SLR observations and to compute multi-satellite solutions. To take benefit of different orbit performances (e.g. inclination and altitude), a solution using ten different spherical satellites (ETALON1/2, LAGEOS1/2, STELLA, STARLETTE, AJISAI, LARETS, LARES, BLITS) covering 12 years of observations is computed. The satellites are relatively weighted using a variance component estimation (VCE). The obtained weights are analyzed w.r.t. the potential of the satellite to monitor changes in the Earths geometry, rotation and gravity field. The estimated parameters (station coordinates and EOP) are validated w.r.t. official time series of the IERS. The obtained Stokes coefficients are compared to recent gravity field solutions and discussed in detail.

  6. Estimating the Earth's geometry, rotation and gravity field using a multi-satellite SLR solution

    NASA Astrophysics Data System (ADS)

    Stefka, V.; Blossfeld, M.; Mueller, H.; Gerstl, M.; Panafidina, N.

    2012-12-01

    Satellite Laser Ranging (SLR) is the unique technique to determine station coordinates, Earth Orientation Parameter (EOP) and Stokes coefficients of the Earth's gravity field in one common adjustment. These parameters form the so called "three pillars" (Plag & Pearlman, 2009) of the Global Geodetic Observing System (GGOS). In its function as official analysis center of the International Laser Ranging Service (ILRS), DGFI is developing and maintaining software to process SLR observations called "DGFI Orbit and Geodetic parameter estimation Software" (DOGS). The software is used to analyze SLR observations and to compute multi-satellite solutions. To take benefit of different orbit performances (e.g. inclination and altitude), a solution using ten different spherical satellites (ETALON1/2, LAGEOS1/2, STELLA, STARLETTE, AJISAI, LARETS, LARES, BLITS) covering the period of 12 years of observations is computed. The satellites are relatively weighted using a variance component estimation (VCE). The obtained weights are analyzed w.r.t. the potential of the satellite to monitor changes in the Earths geometry, rotation and gravity field. The estimated parameters (station coordinates and EOP) are validated w.r.t. official time series of the IERS. The Stokes coefficients are compared to recent gravity field solutions.

  7. The impact of earth resources exploration from space. [technology assessment/LANDSAT satellites -technological forecasting

    NASA Technical Reports Server (NTRS)

    Nordberg, W.

    1975-01-01

    The use of Earth Resources Technology Satellites in solving global problems is examined. Topics discussed are: (1) management of food, water, and fiber resources; (2) exploration and management of energy and mineral resources; (3) protection of the environment; (4) protection of life and property; and (5) improvements in shipping and navigation.

  8. Celebrate with SATELLITES: An International Polar Year Partnership to Study Earth's Materials

    ERIC Educational Resources Information Center

    Hedley, Mikell Lynne; Czajkowski, Kevin; Struble, Janet; Benko, Terri; Shellito, Brad; Sheridan, Scott; Stasiuk, Mandy Munroe

    2009-01-01

    The SATELLITES program uses geospatial technologies to study surface temperatures of Earth's materials, such as sand, soil, grass, and water. Data are collected using Global Learning and Observations to Benefit the Environment (GLOBE) protocols, which are then used in research projects that are a part of the International Polar Year (IPY).…

  9. 78 FR 19172 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-29

    ... From the Federal Register Online via the Government Publishing Office FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 2 and 25 Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service... proposed rule that appeared in the Federal Register of March 8, 2013. The document proposed rules for...

  10. A study to define meteorological uses and performance requirements for the Synchronous Earth Observatory Satellite

    NASA Technical Reports Server (NTRS)

    Suomi, V. E.; Krauss, R. J.; Barber, D.; Levanon, N.; Martin, D. W.; Mclellan, D. W.; Sikdar, D. N.; Sromovsky, L. A.; Branch, D.; Heinricy, D.

    1973-01-01

    The potential meteorological uses of the Synchronous Earth Observatory Satellite (SEOS) were studied for detecting and predicting hazards to life, property, or the quality of the environment. Mesoscale meteorological phenonmena, and the observations requirements for SEOS are discussed along with the sensor parameters.

  11. System design and specifications. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A design summary of the Earth Observatory Satellite (EOS) is presented. The systems considered in the summary are: (1) the spacecraft structure, (2) electrical power modules, (3) communications and data handling module, (4) attitude determination module, (5) actuation module, and (6) solar array and drive module. The documents which provide the specifications for the systems and the equipment are identified.

  12. Evaluation of scanning earth sensor mechanism on engineering test satellite 4

    NASA Technical Reports Server (NTRS)

    Ikeuchi, M.; Wakabayashi, Y.; Ohkami, Y.; Kida, T.; Ishigaki, T.; Matsumoto, M.

    1983-01-01

    The results of the analysis and the evaluation of flight data obtained from the horizon sensor test project are described. The rotary mechanism of the scanning earth sensor composed of direct drive motor and bearings using solid lubricant is operated satisfactorily. The transmitted flight data from Engineering Test Satellite IV was evaluated in comparison with the design value.

  13. Piracy of Satellite Signals by Domestic Receive-Only Earth Stations.

    ERIC Educational Resources Information Center

    Homan, Steven D.

    Innovations in technology have enabled homeowners to pirate satellite signals intended for cable television operators through the use of home earth-stations. Section 605 of the Communications Act of 1934, which governs reception of signals, is inadequate to regulate this situation because it appears that publication of received programing outside…

  14. Third Earth Resources Technology Satellite-1 Symposium. Volume 1: Technical Presentations, section A

    NASA Technical Reports Server (NTRS)

    Freden, S. C. (Compiler); Mercanti, E. P. (Compiler); Becker, M. A. (Compiler)

    1974-01-01

    Papers presented at the Third Symposium on Significant Results Obtained from the first Earth Resources Technology Satellite covered the areas of: agriculture, forestry, range resources, land use, mapping, mineral resources, geological structure, landform surveys, water resources, marine resources, environment surveys, and interpretation techniques.

  15. Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 4: Compound satellite structures on orbits with synchronized nodal regression

    NASA Astrophysics Data System (ADS)

    Razoumny, Yury N.

    2016-12-01

    Basing on the theory results considered in the previous papers of the series for traditional one-tiered constellation formed on the orbits with the same values of altitudes and inclinations for all the satellites of the constellation, the method for constellation design using compound satellite structures on orbits with different altitudes and inclinations and synchronized nodal regression is developed. Compound, multi-tiered, satellite structures (constellations) are based on orbits with different values of altitude and inclination providing nodal regression synchronization. It is shown that using compound satellite constellations for Earth periodic coverage makes it possible to sufficiently improve the Earth coverage, as compared to the traditional constellations based on the orbits with common altitude and inclination for all the satellites of the constellation, and, as a consequence, to get new opportunities for the satellite constellation design for different types of prospective space systems regarding increasing the quality of observations or minimization of the number of the satellites required.

  16. Effects of DeOrbitSail as applied to Lifetime predictions of Low Earth Orbit Satellites

    NASA Astrophysics Data System (ADS)

    Afful, Andoh; Opperman, Ben; Steyn, Herman

    2016-07-01

    Orbit lifetime prediction is an important component of satellite mission design and post-launch space operations. Throughout its lifetime in space, a spacecraft is exposed to risk of collision with orbital debris or operational satellites. This risk is especially high within the Low Earth Orbit (LEO) region where the highest density of space debris is accumulated. This paper investigates orbital decay of some LEO micro-satellites and accelerating orbit decay by using a deorbitsail. The Semi-Analytical Liu Theory (SALT) and the Satellite Toolkit was employed to determine the mean elements and expressions for the time rates of change. Test cases of observed decayed satellites (Iridium-85 and Starshine-1) are used to evaluate the predicted theory. Results for the test cases indicated that the theory fitted observational data well within acceptable limits. Orbit decay progress of the SUNSAT micro-satellite was analysed using relevant orbital parameters derived from historic Two Line Element (TLE) sets and comparing with decay and lifetime prediction models. This paper also explored the deorbit date and time for a 1U CubeSat (ZACUBE-01). The use of solar sails as devices to speed up the deorbiting of LEO satellites is considered. In a drag sail mode, the deorbitsail technique significantly increases the effective cross-sectional area of a satellite, subsequently increasing atmospheric drag and accelerating orbit decay. The concept proposed in this study introduced a very useful technique of orbit decay as well as deorbiting of spacecraft.

  17. Impact-generated atmospheric plumes: The threat to satellites in low-earth orbit

    SciTech Connect

    Boslough, M.B.; Crawford, D.A.

    1996-02-01

    Computational simulations of the impacts of comet Shoemaker-Levy 9 (SL9) fragments on Jupiter provide a framework for interpreting the observations. A reasonably consistent picture has emerged, along with a more detailed understanding of atmospheric collisional processes. The knowledge gained from the observations and simulations of SL9 has led us to consider the threat of impact-generated plumes to satellites in low-Earth orbit (LEO). Preliminary simulations suggest that impacts of a size that recur about once per century on Earth generate plumes that rise to nearly 1000 km over an area thousands of km in diameter. Detailed modeling of such plumes is needed to quantify this threat to satellites in LEO. Careful observations of high-energy atmospheric entry events using both satellite and ground- based instruments would provide validation for these computational models.

  18. A Model of the Earth's Magnetic Field From Two Years of Swarm Satellite Constellation Data

    NASA Astrophysics Data System (ADS)

    Olsen, N.; Finlay, C. C.; Kotsiaros, S.

    2015-12-01

    Two years of data from ESA's Swarm constellation mission are used to derive a model of the Earth's magnetic field and its time variation (secular variation). The model describes contributions from the core and lithosphere as well as large-scale contributions from the magnetosphere (and its Earth-induced counterpart). We use data from geomagnetic quiet times and co-estimate the Euler angles describing the rotation between the vector magnetometer instrument frame and the North-East-Center (NEC) frame. In addition to the magnetic field observations provided by each of the three Swarm satellites and alongtrack first differences we include the East-west magnetic gradient information provided by the lower Swarm satellite pair, thereby explicitly taking advantage of the constellation aspect of Swarm. We assess the spatial and temporal model resolution that can be obtained from two years of Swarm satellite data by comparison with other recent models that also include non-Swarm magnetic observations.

  19. Optimum satellite orbits for accurate measurement of the earth's radiation budget, summary

    NASA Technical Reports Server (NTRS)

    Campbell, G. G.; Vonderhaar, T. H.

    1978-01-01

    The optimum set of orbit inclinations for the measurement of the earth radiation budget from spacially integrating sensor systems was estimated for two and three satellite systems. The best set of the two were satellites at orbit inclinations of 80 deg and 50 deg; of three the inclinations were 80 deg, 60 deg and 50 deg. These were chosen on the basis of a simulation of flat plate and spherical detectors flying over a daily varying earth radiation field as measured by the Nimbus 3 medium resolution scanners. A diurnal oscillation was also included in the emitted flux and albedo to give a source field as realistic as possible. Twenty three satellites with different inclinations and equator crossings were simulated, allowing the results of thousand of multisatellite sets to be intercompared. All were circular orbits of radius 7178 kilometers.

  20. Linking Satellites Via Earth "Hot Spots" and the Internet to Form Ad Hoc Constellations

    NASA Technical Reports Server (NTRS)

    Mandl, Dan; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix; Lee, Richard Q.; Romanofsky, Robert; Zaman, Afoz; Popovic, Zoya

    2004-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet. the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in satellites. Keywords: collaborative remote sensing smart antennas, adaptive antenna arrays, sensor webs. ad hoc constellations, mission autonomy and

  1. Linking satellites via Earth hot spots and the Internet to form ad hoc constellations

    NASA Astrophysics Data System (ADS)

    Mandl, Daniel; Frye, Stu; Grosvenor, Sandra; Ingram, Mary Ann; Langley, John; Miranda, Felix A.; Lee, Richard Q.; Romanofsky, Robert R.; Zaman, Afroz; Popovic, Zoya; Sherwood, Robert L.; Chien, Steve; Davies, Ashley

    2005-01-01

    As more assets are placed in orbit, opportunities emerge to combine various sets of satellites in temporary constellations to perform collaborative image collections. Often, new operations concepts for a satellite or set of satellites emerge after launch. To the degree with which new space assets can be inexpensively and rapidly integrated into temporary or "ad hoc" constellations, will determine whether these new ideas will be implemented or not. On the Earth Observing 1 (EO-1) satellite, a New Millennium Program mission, a number of experiments were conducted and are being conducted to demonstrate various aspects of an architecture that, when taken as a whole, will enable progressive mission autonomy. In particular, the target architecture will use adaptive ground antenna arrays to form, as close as possible, the equivalent of wireless access points for low earth orbiting satellites. Coupled with various ground and flight software and the Internet, the architecture enables progressive mission autonomy. Thus, new collaborative sensing techniques can be implemented post-launch. This paper will outline the overall operations concept and highlight details of both the research effort being conducted in the area of adaptive antenna arrays and some of the related successful autonomy software that has been implemented using EO-1 and other operational satellites.

  2. The Orbit and Future Motion of Earth Quasi-Satellite 2016 HO3

    NASA Astrophysics Data System (ADS)

    Chodas, Paul

    2016-10-01

    The newly discovered small asteroid 2016 HO3 is not only co-orbital with the Earth, it is currently trapped as a quasi-satellite, and it will remain a constant companion of our planet for centuries to come. Although it orbits the Sun, not the Earth, in a frame rotating with the Earth the asteroid appears to make yearly loops around our planet, and also bobs up and down through the ecliptic due to its 8-degree orbital inclination. What makes this asteroid a quasi-satellite is the fact that the Earth's gravity influences its motion so that it never wanders farther away than about 100 lunar distances. In the rotating frame, the asteroid's yearly cycles librate back and forth along the Earth's orbit, with a period of about 45 years. One other asteroid, 2003 YN107, followed a similar librational pattern from 1997 to 2006, but has since departed our vicinity. 2016 HO3, on the other hand, will continue to librate about our planet for centuries to come, making it the best and most stable example of a quasi-satellite to date.

  3. High resolution earth observation satellites and services in the next decade a European perspective

    NASA Astrophysics Data System (ADS)

    Schreier, Gunter; Dech, Stefan

    2005-07-01

    Projects to use very high resolution optical satellite sensor data started in the late 90s and are believed to be the major driver for the commercialisation of earth observation. The global political security situation and updated legislative frameworks created new opportunities for high resolution, dual use satellite systems. In addition to new optical sensors, very high resolution synthetic aperture radars will become in the next few years an important component in the imaging satellite fleet. The paper will review the development in this domain so far, and give perspectives on future emerging markets and opportunities. With dual-use satellite initiatives and new political frameworks agreed between the European Commission and the European Space Agency (ESA), the European market becomes very attractive for both service suppliers and customers. The political focus on "Global Monitoring for Environment and Security" (GMES) and the "European Defence and Security Policy" drive and amplify this demand which ranges from low resolution climate monitoring to very high resolution reconnaissance tasks. In order to create an operational and sustainable GMES in Europe by 2007, the European infrastructure need to be adapted and extended. This includes the ESA SENTINEL and OXYGEN programmes, aiming for a fleet of earth observation satellites and an open and operational earth observation ground segment. The harmonisation of national and regional geographic information is driven by the European Commission's INSPIRE programme. The necessary satellite capacity to complement existing systems in the delivery of space based data required for GMES is currently under definition. Embedded in a market with global competition and in the global political framework of a Global Earth Observation System of Systems, European companies, agencies and research institutions are now contributing to this joint undertaking. The paper addresses the chances, risks and options for the future.

  4. Asteroid (469219) 2016 HO3, the smallest and closest Earth quasi-satellite

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, C.; de la Fuente Marcos, R.

    2016-11-01

    A number of Earth co-orbital asteroids experience repeated transitions between the quasi-satellite and horseshoe dynamical states. Asteroids 2001 GO2, 2002 AA29, 2003 YN107 and 2015 SO2 are well-documented cases of such a dynamical behaviour. These transitions depend on the gravitational influence of other planets, owing to the overlapping of a multiplicity of secular resonances. Here, we show that the recently discovered asteroid (469219) 2016 HO3 is a quasi-satellite of our planet - the fifth one, joining the ranks of (164207) 2004 GU9, (277810) 2006 FV35, 2013 LX28, and 2014 OL339. This new Earth co-orbital also switches repeatedly between the quasi-satellite and horseshoe configurations. Its current quasi-satellite episode started nearly 100 yr ago and it will end in about 300 yr from now. The orbital solution currently available for this object is very robust and our full N-body calculations show that it may be a long-term companion (time-scale of Myr) to our planet. Among the known Earth quasi-satellites, it is the closest to our planet and as such, a potentially accessible target for future in situ study. Due to its presumably lengthy dynamical relationship with the Earth and given the fact that at present and for many decades this transient object remains well positioned with respect to our planet, the results of spectroscopic studies of this small body, 26-115 m, may be particularly useful to improve our understanding of the origins - local or captured - of Earth's co-orbital asteroid population. The non-negligible effect of the uncertainty in the value of the mass of Jupiter on the stability of this type of co-orbitals is also briefly explored.

  5. Ocean tide models for satellite geodesy and Earth rotation

    NASA Technical Reports Server (NTRS)

    Dickman, Steven R.

    1991-01-01

    A theory is presented which predicts tides in turbulent, self-gravitating, and loading oceans possessing linearized bottom friction, realistic bathymetry, and continents (at coastal boundaries no-flow conditions are imposed). The theory is phrased in terms of spherical harmonics, which allows the tide equations to be reduced to linear matrix equations. This approach also allows an ocean-wide mass conservation constraint to be applied. Solutions were obtained for 32 long and short period luni-solar tidal constituents (and the pole tide), including the tidal velocities in addition to the tide height. Calibrating the intensity of bottom friction produces reasonable phase lags for all constituents; however, tidal amplitudes compare well with those from observation and other theories only for long-period constituents. In the most recent stage of grant research, traditional theory (Liouville equations) for determining the effects of angular momentum exchange on Earth's rotation were extended to encompass high-frequency excitations (such as short-period tides).

  6. Views of Earth's magnetosphere with the image satellite.

    PubMed

    Burch, J L; Mende, S B; Mitchell, D G; Moore, T E; Pollock, C J; Reinisch, B W; Sandel, B R; Fuselier, S A; Gallagher, D L; Green, J L; Perez, J D; Reiff, P H

    2001-01-26

    The IMAGE spacecraft uses photon and neutral atom imaging and radio sounding techniques to provide global images of Earth's inner magnetosphere and upper atmosphere. Auroral imaging at ultraviolet wavelengths shows that the proton aurora is displaced equatorward with respect to the electron aurora and that discrete auroral forms at higher latitudes are caused almost completely by electrons. Energetic neutral atom imaging of ions injected into the inner magnetosphere during magnetospheric disturbances shows a strong energy-dependent drift that leads to the formation of the ring current by ions in the several tens of kiloelectron volts energy range. Ultraviolet imaging of the plasmasphere has revealed two unexpected features-a premidnight trough region and a dayside shoulder region-and has confirmed the 30-year-old theory of the formation of a plasma tail extending from the duskside plasmasphere toward the magnetopause.

  7. Simulation on change of generic satellite radar cross section via artificially created plasma sprays

    NASA Astrophysics Data System (ADS)

    Chung, Shen Shou Max; Chuang, Yu-Chou

    2016-06-01

    Recent advancements in antisatellite missile technologies have proven the effectiveness of such attacks, and the vulnerability of satellites in such exercises inspires a new paradigm in RF Stealth techniques suitable for satellites. In this paper we examine the possibility of using artificially created plasma sprays on the surface of the satellite’s main body to alter its radar cross section (RCS). First, we briefly review past research related to RF Stealth using plasma. Next, we discuss the physics between electromagnetic waves and plasma, and the RCS number game in RF Stealth design. A comparison of RCS in a generic satellite and a more complicated model is made to illustrate the effect of the RCS number game, and its meaning for a simulation model. We also run a comparison between finite-difference-time-domain (FDTD) and multilevel fast multipole method (MLFMM) codes, and find the RCS results are very close. We then compare the RCS of the generic satellite and the plasma-covered satellite. The incident radar wave is a differentiated Gaussian monopulse, with 3 dB bandwidth between 1.2 GHz and 4 GHz, and we simulate three kinds of plasma density, with a characteristic plasma frequency ω P  =  0.1, 1, and 10 GHz. The electron-neutral collision frequency ν en is set at 0.01 GHz. We found the RCS of plasma-covered satellite is not necessarily smaller than the originally satellite. When ω P is 0.1 GHz, the plasma spray behaves like a dielectric, and there is minor reduction in the RCS. When ω P is 1 GHz, the X-Y cut RCS increases. When ω P is 10 GHz, the plasma behaves more like a metal to the radar wave, and stronger RCS dependency to frequency appears. Therefore, to use plasma as an RCS adjustment tool requires careful fine-tuning of plasma density and shape, in order to achieve the so-called plasma stealth effect.

  8. Content-Aware Adaptive Compression of Satellite Imagery Using Artificial Vision

    DTIC Science & Technology

    2013-09-01

    in ICAPS, 2004, pp. 142–149. [24] J. E. Fowler, S. Mun, and E. W. Tramel, “Block- based compressed sensing of images and video,” Foundations and...Imagery Compression algorithm (OASIC) aims to conserve satellite channel capacity when transmitting oceanic imagery to Earth. OASIC conserves chan...losses, respectively. C N0 = AtPt(LpLd)Ar KTe (1.1) 2 Channel capacity, is the rate at which bits can be propagated through the range of frequencies

  9. The role of artificial atmospheric CO2 removal in stabilizing Earth's climate

    NASA Astrophysics Data System (ADS)

    Zickfeld, K.; Tokarska, K.

    2014-12-01

    The current CO2 emission trend entails a risk that the 2°C target will be missed, potentially causing "dangerous" changes in Earth's climate system. This research explores the role of artificial atmospheric CO2 removal (also referred to as "negative emissions") in stabilizing Earth's climate after overshoot. We designed a range of plausible CO2 emission scenarios, which follow a gradual transition from a fossil fuel driven economy to a zero-emission energy system, followed by a period of negative emissions. The scenarios differ in peak emissions rate and, accordingly, the amount of negative emissions, to reach the same cumulative emissions compatible with the 2°C temperature stabilization target. The climate system components' responses are computed using the University of Victoria Earth System Climate Model of intermediate complexity. Results suggest that negative emissions are effective in reversing the global mean temperature and stabilizing it at a desired level (2°C above pre-industrial) after overshoot. Also, changes in the meridional overturning circulation and sea ice are reversible with the artificial removal of CO2 from the atmosphere. However, sea level continues to rise and is not reversible for several centuries, even under assumption of large amounts of negative emissions. For sea level to decline, atmospheric CO2 needs to be reduced to pre-industrial levels in our simulations. During the negative emission phase, outgassing of CO2 from terrestrial and marine carbon sinks offsets the artificial removal of atmospheric CO2, thereby reducing its effectiveness. On land, the largest CO2 outgassing occurs in the Tropics and is partially compensated by CO2 uptake at northern high latitudes. In the ocean, outgassing occurs mostly in the Southern Ocean, North Atlantic and tropical Pacific. The strongest outgassing occurs for pathways entailing greatest amounts of negative emissions, such that the efficiency of CO2 removal - here defined as the change in

  10. Human artificial chromosome assembly by transposon-based retrofitting of genomic BACs with synthetic alpha-satellite arrays.

    PubMed

    Basu, Joydeep; Willard, Huntington F; Stromberg, Gregory

    2007-01-01

    The development of methodologies for the rapid assembly of synthetic alpha-satellite arrays recapitulating the higher-order periodic organization of native human centromeres permits the systematic investigation of the significance of primary sequence and sequence organization in centromere function. Synthetic arrays with defined mutations affecting sequence and/or organization may be evaluated in a de novo human artificial chromosome assay. This unit describes strategies for the assembly of custom built alpha-satellite arrays containing any desired mutation as well as strategies for the construction and manipulation of alpha satellite-based transposons. Transposons permit the rapid and reliable retrofitting of any genomic bacterial artificial chromosome (BAC) with synthetic alpha-satellite arrays and other functional components, thereby facilitating conversion into BAC-based human artificial chromosome vectors. These techniques permit identification and optimization of the critical parameters underlying the unique ability of alpha-satellite DNA to facilitate de novo centromere assembly, and they will establish the foundation for the next generation of human artificial chromosome vectors.

  11. Earth zonal harmonics from rapid numerical analysis of long satellite arcs

    NASA Technical Reports Server (NTRS)

    Wagner, C. A.

    1972-01-01

    A zonal geopotential is presented to degree 21 from evaluation of mean elements for 21 satellites including 2 of low inclination. Each satellite is represented by an arc of at least one apsidal rotation. The lengths range from 200 to 800 days. Differential correction of the initial elements in all of the arcs, together with radiation pressure and atmospheric drag coefficients, was accomplished simultaneously with the correction for the zonal harmonics. The satellite orbits and their variations are generated by numerical integration of the Lagrange equations for mean elements. Disturbances due to precession and nutation of the earth's pole, atmospheric drag, radiation pressure and luni-solar gravity are added at from 1- to 8-day intervals in the integrated orbits. The results agree well with recent solutions from other authors using different methods and different satellite sets.

  12. Determination of Pole and Rotation Period of not Stabilized Artificial Satellite by Use of Model "diffuse Cylinder"

    NASA Astrophysics Data System (ADS)

    Kolesnik, S. Ya.; Dobrovolsky, A. V.; Paltsev, N. G.

    The algorithm of determination of orientation of rotation axis (pole) and rotation period of satellite, simulated by a cylinder, which is precessing around of vector of angular moment of pulse with constant nutation angle is offered. The Lambert's law of light reflection is accepted. Simultaneously, dependence of light reflection coefficient versus phase angle is determined. The model's simulation confirm applicability of this method. Results of the calculations for artificial satellite No 28506 are carried out.

  13. GEMMA: An Earth crustal model based on GOCE satellite data

    NASA Astrophysics Data System (ADS)

    Reguzzoni, M.; Sampietro, D.

    2015-03-01

    The boundary between Earth's crust and mantle is commonly modelled as a discontinuity surface, the so-called Moho. Although in some regions of the world this model may be too approximate or even unrealistic, globally speaking it can provide a key to read several long wavelength geophysical signals. Recent research activities have shown the possibility to estimate the Moho discontinuity worldwide from global gravity field model, however usually the solution of this inverse problem requires strong unrealistic hypotheses. In this work a new procedure to relax some of these unrealistic hypotheses is devised and described in details. Basically it allows to estimate the mean Moho depth even once the normal gravitational field is removed if at least one seismic observation is available, to take into account the dependency of the crust density on the radial direction (usually neglected in Moho depth determination from gravity), to correct the a-priori density model of the crystalline crust for scale factors again using seismic information and finally to consider a Moho with a non-constant depth as reference surface in the inversion, thus reducing the linearization error. The new procedure is here applied to GOCE data to estimate a new crustal model. For this purpose additional external information has been used, such as topography, bathymetry and ice sheet models from ETOPO1, a recent 1° × 1° sediment global model and some prior hypotheses on crustal density. In particular the main geological provinces, each of them characterized by its own relation between density and depth, have been considered. A model describing lateral density variations of the upper mantle is also taken into account. The new crustal model is computed at a spatial resolution of 0.5° × 0.5°, its gravitational effect differs from GOCE observations of 49 mE and its Moho depth error standard deviation is globally of 3.4 km. Therefore the result seems to be an improvement in terms of resolution

  14. Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2009-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR, and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time as well as the ability to intervene using manual override to teleoperate the robot.

  15. Precise Orbit Determination Of Low Earth Satellites At AIUB Using GPS And SLR Data

    NASA Astrophysics Data System (ADS)

    Jaggi, A.; Bock, H.; Thaller, D.; Sosnica, K.; Meyer, U.; Baumann, C.; Dach, R.

    2013-12-01

    An ever increasing number of low Earth orbiting (LEO) satellites is, or will be, equipped with retro-reflectors for Satellite Laser Ranging (SLR) and on-board receivers to collect observations from Global Navigation Satellite Systems (GNSS) such as the Global Positioning System (GPS) and the Russian GLONASS and the European Galileo systems in the future. At the Astronomical Institute of the University of Bern (AIUB) LEO precise orbit determination (POD) using either GPS or SLR data is performed for a wide range of applications for satellites at different altitudes. For this purpose the classical numerical integration techniques, as also used for dynamic orbit determination of satellites at high altitudes, are extended by pseudo-stochastic orbit modeling techniques to efficiently cope with potential force model deficiencies for satellites at low altitudes. Accuracies of better than 2 cm may be achieved by pseudo-stochastic orbit modeling for satellites at very low altitudes such as for the GPS-based POD of the Gravity field and steady-state Ocean Circulation Explorer (GOCE).

  16. Analyses of earth radiation budget data from unrestricted broadband radiometers on the ESSA 7 satellite

    NASA Technical Reports Server (NTRS)

    Weaver, W. L.; House, F. B.

    1979-01-01

    Six months of data from the wide-field-of-view low resolution infrared radiometers on the Environmental Science Services Administration (ESSA) 7 satellite were analyzed. Earth emitted and earth reflected irradiances were computed at satellite altitude using data from a new in-flight calibration technique. Flux densitites and albedos were computed for the top of the earth's atmosphere. Monthly averages of these quantities over 100 latitude zones, each hemisphere, and the globe are presented for each month analyzed, and global distributions are presented for typical months. Emitted flux densities are generally lower and albedos higher than those of previous studies. This may be due, in part, to the fact that the ESSA 7 satellite was in a 3 p.m. Sun-synchronous orbit and some of the comparison data were obtained from satellites in 12 noon sun-synchronous orbits. The ESSA 7 detectors seem to smooth out spatial flux density variations more than scanning radiometers or wide-field-of-view fixed-plate detectors. Significant longitudinal and latitudinal variations of emitted flux density and albedo were identified in the tropics in a zone extending about + or - 25 deg in latitude.

  17. The Role of Satellite Earth Observation Data in Monitoring and Verifying International Environmental Treaties

    NASA Technical Reports Server (NTRS)

    Johnston, Shaida

    2004-01-01

    The term verification implies compliance verification in the language of treaty negotiation and implementation, particularly in the fields of disarmament and arms control. The term monitoring on the other hand, in both environmental and arms control treaties, has a much broader interpretation which allows for use of supporting data sources that are not necessarily acceptable or adequate for direct verification. There are many ways that satellite Earth observation (EO) data can support international environmental agreements, from national forest inventories to use in geographic information system (GIs) tools. Though only a few references to satellite EO data and their use exist in the treaties themselves, an expanding list of applications can be considered in support of multilateral environmental agreements (MEAs). This paper explores the current uses of satellite Earth observation data which support monitoring activities of major environmental treaties and draws conclusions about future missions and their data use. The scope of the study includes all phases of environmental treaty fulfillment - development, monitoring, and enforcement - and includes a multinational perspective on the use of satellite Earth observation data for treaty support.

  18. Modeling the satellite particle population in the planetary exospheres: Application to Earth, Titan and Mars

    NASA Astrophysics Data System (ADS)

    Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Mazelle, C.; Kotova, A.

    2014-01-01

    The planetary exospheres are poorly known in their outer parts, since the low neutral densities are difficult to measure in situ. The exospheric models are thus often the main source of information at such high altitudes. We revisit here the importance of a specific exospheric population, i.e. the satellite particles, which is usually neglected in the models. These particles are indeed produced through rare collisions in the exospheres, and may either be negligible or dominate the exospheres of all planets with dense atmospheres in our Solar System, depending on the balance between their sources and losses. Richter et al. (Richter, E., Fahr, H.J., Nass, H.U. [1979]. Planet. Space Sci. 27, 1163-1173) were the first to propose, beyond the Chamberlain's (Chamberlain, J.W. [1963]. Planet. Space Sci. 11, 901-901) rough approximation, a rigorous approach for these particles by using the Boltzmann equation in the Earth exosphere below 3000 km altitude. They pointed out their negligible presence at low altitudes without doing this calculation at higher altitudes. We further investigate this approach at Earth and apply it another planetary exospheres - Mars and Titan - thanks to improvements in the computing power and the collected planetary data. We determine the contribution of the satellite particles densities of light elements (H2 at Titan, H at Earth and Mars), and show in particular that the H satellite particles may contribute very significantly to the martian exospheric densities at high altitudes. The H2 satellite particles are also nonnegligible at Titan whereas the H satellite population represents only a small fraction of the total density at Earth. Considering collisionless exospheric profiles - such as the Chamberlain (Chamberlain, J.W. [1963]. Planet. Space Sci. 11, 901-901) approach including the ballistic and escaping populations only - could thus lead to significant underestimations of the total densities at high altitudes in some conditions.

  19. Citizen Explorer. 1; An Earth Observer With New Small Satellite Technology

    NASA Technical Reports Server (NTRS)

    Allen, Zachary; Dunn, Catherine E.

    2003-01-01

    Citizen Explorer-I (CX-I), designed and built by students at Colorado Space Grant Consortium in Boulder to provide global ozone monitoring, employs a unique mission architecture and several innovative technologies during its mission. The mission design allows K-12 schools around the world to be involved as ground stations available to receive science data and telemetry from CX-I. Another important technology allows the spacecraft to be less reliant on ground operators. Spacecraft Command Language (SCL) allows mission designers to set constraints on the satellite operations. The satellite then automatically adheres to the constraints when the satellite is out of contact with Mission Operations. In addition to SCL, a low level of artificial intelligence will be supplied to the spacecraft through the use of the Automated Scheduling and Planning ENvironment (ASPEN). ASPEN is used to maintain a spacecraft schedule in order to achieve the objectives a mission operator would normally have to complete. Within the communications system of CX-I, internet of CX-I, internet protocols are the main method for communicating with the satellite. As internet protocols have not been widely used in satellite communication, CX-I provides an opportunity to study the effectiveness of using internet protocols over radio links. The Attitude Determination and Control System (ADCS) on CX-I uses a gravity gradient boom as a means of orienting the satellite's science instruments toward nadir. The boom design is unique because it is constructed of tape measure material. These new technologies' effectiveness will be tested for use on future small satellite projects within the space satellite industry.

  20. Space-shuttle interfaces/utilization. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The economic aspects of space shuttle application to a representative Earth Observatory Satellite (EOS) operational mission in the various candidate Shuttle modes of launch, retrieval, and resupply are discussed. System maintenance of the same mission capability using a conventional launch vehicle is also considered. The studies are based on application of sophisticated Monte Carlo mission simulation program developed originally for studies of in-space servicing of a military satellite system. The program has been modified to permit evaluation of space shuttle application to low altitude EOS missions in all three modes. The conclusions generated by the EOS system study are developed.

  1. Space Network IP Services (SNIS): An Architecture for Supporting Low Earth Orbiting IP Satellite Missions

    NASA Technical Reports Server (NTRS)

    Israel, David J.

    2005-01-01

    The NASA Space Network (SN) supports a variety of missions using the Tracking and Data Relay Satellite System (TDRSS), which includes ground stations in White Sands, New Mexico and Guam. A Space Network IP Services (SNIS) architecture is being developed to support future users with requirements for end-to-end Internet Protocol (IP) communications. This architecture will support all IP protocols, including Mobile IP, over TDRSS Single Access, Multiple Access, and Demand Access Radio Frequency (RF) links. This paper will describe this architecture and how it can enable Low Earth Orbiting IP satellite missions.

  2. High data rate x-band transmitter for low Earth orbit satellites

    NASA Astrophysics Data System (ADS)

    Sen, O.; Sunay, H.; Ismailoglu, Neslin; Kirdmaz; Dudak, Celal

    2004-11-01

    Small satellite communication systems require high data rate, high-efficiency and simple transmitters, without sacrificing efficiency and linearity depending on the modulation scheme. Main purpose of this study is to design a low power, simple and low weight transmitter with data rates up to 100 Mbps, BPSK/QPSK/OQPSK modulation and 7W output power at 8.2 GHz for low earth orbit (LEO) satellites in order to satisfy the high data rate demand. Output power of the transmitter is chosen to be 7W (38.5 dBm), which satisfies the link budget for LEO at 680 km and BER performance of 1e-6 .

  3. Research at the earth's edge. [tethered satellite study of upper atmosphere

    NASA Technical Reports Server (NTRS)

    Anderson, John L.; Wood, George M., Jr.; Siemers, Paul M.

    1988-01-01

    The Space Shuttle Orbiter-deployed Tethered Satellite System (TSS) could allow an Orbiter at a 200 km orbital altitude to reach down to atmospheric altitudes of 90 km, in order to study weather phenomena, pollutant transport, 'nuclear winter' smoke transport, atmospheric physics and dynamics, sun-earth interactions, ecosystem interactions, and radio communications. The TSS satellite, a 1.5-m diameter sphere, would carry scientific instrumentation which could initially be dedicated to the investigation of energy and momentum transfer between a tethered system and the upper atmosphere.

  4. Improvement of the Earth's gravity field from terrestrial and satellite data

    NASA Technical Reports Server (NTRS)

    1987-01-01

    The terrestrial gravity data base was updated. Studies related to the Geopotential Research Mission (GRM) have primarily considered the local recovery of gravity anomalies on the surface of the Earth based on satellite to satellite tracking or gradiometer data. A simulation study was used to estimate the accuracy of 1 degree-mean anomalies which could be recovered from the GRM data. Numerous procedures were developed for the intent of performing computations at the laser stations in the SL6 system to improve geoid undulation calculations.

  5. SERIES-X test results. [for measuring TOPEX earth satellite orbits

    NASA Technical Reports Server (NTRS)

    Crow, R. B.; Bletzacker, F. R.; Najarian, R. J.; Purcell, G. H., Jr.; Statman, J. I.; Thomas, J. B.

    1984-01-01

    The SERIES-X project which demonstrates the feasibility of a method involving measurements of the distance from the TOPEX earth satellite and various points on the ground to Global Positioning System (GPS) satellites is described. The features of SERIES-X are compared with three better-known geodetic-quality GPS systems (Geostar, Macrometer, and SERIES). It is shown that the system is capable of measuring the positions of isolated stations, but its accuracy is improved when it measures baselines. Test results of some measurements of baselines ranging in length from 15 to 171,000 m are presented and discussed.

  6. Candidate configuration trade study, Stellar-inertial Measurement Systems (SIMS) for an Earth Observation Satellite (EOS)

    NASA Technical Reports Server (NTRS)

    Ogletree, G.; Coccoli, J.; Mckern, R.; Smith, M.; White, R.

    1972-01-01

    The results of analytical and simulation studies of the stellar-inertial measurement system (SIMS) for an earth observation satellite are presented. Subsystem design analyses and sensor design trades are reported. Three candidate systems are considered: (1) structure-mounted gyros with structure-mounted star mapper, (2) structure-mounted gyros with gimbaled star tracker, and (3) gimbaled gyros with structure-mounted star mapper. The purpose of the study is to facilitate the decisions pertaining to gimbaled versus structure-mounted gyros and star sensors, and combinations of systems suitable for the EOS satellite.

  7. The Grace Mission: The Challenges of Using Micron-Level Satellite-to-Satellite Ranging to Measure the Earth's Gravity Field

    NASA Technical Reports Server (NTRS)

    Watkins, M.; Bettadpur, S.

    2000-01-01

    The GRACE Mission, to be launched in mid-2001, will provide an unprecedented map of the Earth's gravity field every month. In this paper, we outline the challenges associated with this micron-level satellite-to-satellite ranging, the solutions used by the GRACE project, and the expected science applications of the data.

  8. Effect of limb darkening on earth radiation incident on a spherical satellite

    NASA Technical Reports Server (NTRS)

    Katzoff, S.; Smith, G. L.

    1974-01-01

    The thermal radiation from the earth incident on a spherical satellite depends on the angular distribution of earth-emitted radiation. An analysis is presented of this dependency, and calculated results are given, based on a published limb-darkening curve for the earth. The curve was determined from Tiros data, and is a statistical average over the entire globe between 75 deg latitude. The computed effect of limb darkening was 1.8 percent at 900 km altitude, 2.5 percent at 500 km altitude, and 3.0 percent at 300 km altitude. Below 300 km, it increased rapidly with decreasing altitude. Discussion is included of various other problems inherent in the use of orbiting spheres and stabilized flat plates to measure the heat radiated from the earth.

  9. Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 1: Analytic emulation of the Earth coverage

    NASA Astrophysics Data System (ADS)

    Razoumny, Yury N.

    2016-11-01

    This paper opens a series of articles expounding the fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. In Part 1 of the series the analytical model for Earth coverage by satellites' swath conforming to the essential of discontinuous coverage, in contrast to continuous coverage, is presented. The analytic relations are consecutively derived for calculation of single- and multi-satellite Earth surface latitude coverage as well as for generating full set of typical satellite visibility zone time streams realized in the repeating latitude coverage pattern for given arbitrary satellite constellation. The analytic relations mentioned are used for developing the method for analysis of discontinuous coverage of fixed arbitrary Earth region for given satellite constellation using both deterministic and stochastic approaches. The method provides analysis of the revisit time for given satellite constellation, as a result of high speed (fractions of a second or seconds) computer calculations in a wide range of possible revisit time variations for different practical purposes with high accuracy which is at least on par with that provided by known numerical simulating methods based on direct modeling of the satellite observation mission, or in a number of cases is even superior to it.

  10. NASA Perspectives on Earth Observations from Satellite or 50 Years of Meteorological Satellite Experiments-The NASA Perspective

    NASA Technical Reports Server (NTRS)

    Einaudi, Franco

    2010-01-01

    The NASA was established in 1959. From those very eady days to the present NASA has been intimately involved with NOAA and the scientific community in the development and operation of satellite and sensor experiments. The early efforts included experiments on the TIROS and geostationary Applications Technology Satellites (ATS) series. In the latter case the spin-scan cameras conceived by Verner Suomi, along with the TIROS cameras, opened new vistas at what could be done in meteorological studies with the daily, nearly global, synoptic views from space-borne sensors As the years passed and the Nimbus series of satellites came into being in the 1960's, more quantitative observations with longer-lifetime, increasingly capable, better calibrated instruments came into being. NASA, in collaboration with and in support of NOAA, implemented operational systems that we now know as the Polar Operational Environmental Satellite (POES) series and the Geostationary Operational Environmental Satellite (GOES) series that provided dependable, continuous, dedicated satellite observations for use by the weather and atmospheric science communities. Through the 1970's, 1980's, and 1990's improved, well-calibrated instruments with more spectral bands extending into the thermal and the microwave portions of the electromagnetic spectrum were provided to obtain accurate soundings of the atmosphere, atmospheric chemistry constituents such as ozone, global sea surface temperature, snow and ice extent, vegetation dynamics, etc. In the 1990's and up to the present the NASA/Earth Observing System (EOS) has been developed, implemented, and operated over many years to provide a very comprehensive suite of observations of the atmosphere, as well as land and ocean parameters. The future looks bright wherein the development of new systems, broadly described by the National Academy of Science Decadal Study, is now underway. NASA, along with collaborations with NOAA, other agencies, and the

  11. Sampling Errors of Monthly-mean Radiative Fluxes from the Earth Radiation Budget Satellite

    NASA Technical Reports Server (NTRS)

    Bess, T. Dale; Wong, Takmeng; Smith, G. Louis

    2002-01-01

    The Earth Radiation Experiment (ERBE) consisted of scanning and non-scanning radiometers on the dedicated Earth Radiation Budget Satellite ERBS) and also on the NOAA-9 and -10 operational spacecraft. The non-scanning radiometers included a pair of wide field-of-view (WFOV) radiometers for measuring outgoing longwave radiation and reflected solar radiation (Luther et al., 1986). The ERBS was placed into an orbit with 57 deg. inclination and 620 km altitude on 16 October 1984. The instruments began collecting data in November 1984 and the non-scanning radiometers provided data until June 2002, providing a 17-year data set.

  12. Nimbus 6 ERB scanner studies for development of Earth Radiation Budget Satellite System (ERBSS)

    NASA Technical Reports Server (NTRS)

    Suttles, J. T.; Avis, L. M.; Renfroe, P. G.

    1977-01-01

    The Nimbus 6 ERB scanner data were conducted to support the development of the Earth Radiation Budget Satellite System project. The ERB data were processed in terms of Earth targets and angular bins and used to evaluate currently available directional radiation models for the longwave and shortwave spectral ranges. Results indicate that available longwave models are adequate for the most part while available shortwave models are inadequate. An effort was initiated to develop improved shortwave models for various cloud conditions and various surface types for cloud free conditions.

  13. Electric propulsion systems for small satellites: the low earth orbit mission perseus

    NASA Astrophysics Data System (ADS)

    Bock, D.; Herdrich, G.; Lau, M.; Lengowski, M.; Schönherr, T.; Steinmetz, F.; Wollenhaupt, B.; Zeile, O.; Röser, H.-P.

    2011-10-01

    The Institute of Space Systems, Universität Stuttgart, launched a "Small a Satellite Program" in 2002. The first two of the four planed small satellites, Flying Laptop and PERSEUS, are both Low Earth Orbit (LEO) missions. The third mission Cermit is a reentry satellite and the last of the small satellites - Lunar Mission BW1 - is a mission to the Moon. For this purpose, different propulsion systems are mandatory. The propulsion system for Lunar Mission BW1 will consist of two different types of thruster systems: a cluster of pulsed magnetoplasmadynamic (MPD) thrusters (SIMP-LEX) using solid polytetrafluoroethylene (PTFE) as propellant and a thermal arcjet thruster (TALOS) using gaseous ammonia as propellant. Both thruster systems are currently under development at IRS. They are planned to be tested on board the small satellite mission PERSEUS, one of the precursor missions of Lunar Mission BW1. The thruster systems have been investigated intensely in the past and, furthermore, optimization of the thrusters with respect to the mission requirements of Lunar Mission BW1 has been started. The test procedures for the technology demonstration on the PERSEUS satellite are under development at present.

  14. Recent Direct Measurements by Satellites of Cosmic Dust in the Vicinity of the Earth

    NASA Technical Reports Server (NTRS)

    LaGow, H. E.; Alexander, W. M.

    1960-01-01

    Direct measurements of the space density of cosmic dust particles in the vicinity of the earth have been made from rockets, satellites, and space probes. The largest data samples have been obtained from crystal transducer sensors that detect the impact-impulses occurring from the collision of dust particles on sensitive surfaces of space vehicles. Preliminary results from satellite 1959 Eta show: (1) over 1500 impacts and an area-time product greater than 10(exp 1O) sq cm-sec; and (2) a daily variation in the dust particle density near the earth. The dust particle instrumentation of 1959 Eta and sensor calibration techniques are discussed in this paper. The results of direct measurements from space vehicles prior to 1959 Eta are summarized with respect to 1959 Eta information.

  15. Optimal approach to the investigation of the Earth's gravitational field by means of satellite gradiometry.

    NASA Astrophysics Data System (ADS)

    Petrovskaya, M. S.

    The conventional approach to the recovery of the Earth's gravitational field from satellite gradiometry observations is based on constructing, from the start, several boundary value (BV) relations, each of them corresponding to a separate observable component of the gravity gradient (GG) tensor or a certain combination of them. In particular, one of such projects, the ARISTOTELES mission, assumes that only the radial and across-track components are accessible (by technical reasons). The purpose of the present paper is mainly to discuss the principle aspects of the problem of the Earth's potential recovering from satellite gradiometry, to give an optimal formulation of the problem and derive the basic boundary value equation in different forms.

  16. Earth Observatory Satellite system definition study. Report 3: Design cost trade-off studies and recommendations

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An analysis of the design and cost tradeoff aspects of the Earth Observatory Satellite (EOS) development is presented. The design/cost factors that affect a series of mission/system level concepts are discussed. The subjects considered are as follows: (1) spacecraft subsystem cost tradeoffs, (2) ground system cost tradeoffs, and (3) program cost summary. Tables of data are provided to summarize the results of the analyses. Illustrations of the various spacecraft configurations are included.

  17. Attitude estimation of earth orbiting satellites by decomposed linear recursive filters

    NASA Technical Reports Server (NTRS)

    Kou, S. R.

    1975-01-01

    Attitude estimation of earth orbiting satellites (including Large Space Telescope) subjected to environmental disturbances and noises was investigated. Modern control and estimation theory is used as a tool to design an efficient estimator for attitude estimation. Decomposed linear recursive filters for both continuous-time systems and discrete-time systems are derived. By using this accurate estimation of the attitude of spacecrafts, state variable feedback controller may be designed to achieve (or satisfy) high requirements of system performance.

  18. Earth Observatory Satellite system definition study. Report 4: Low cost management approach and recommendations

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An analysis of low cost management approaches for the development of the Earth Observatory Satellite (EOS) is presented. The factors of the program which tend to increase costs are identified. The NASA/Industry interface is stressed to show how the interface can be improved to produce reduced program costs. Techniques and examples of cost reduction which can be applied to the EOS program are tabulated. Specific recommendations for actions to be taken to reduce costs in prescribed areas are submitted.

  19. An optimized end-to-end process for the analysis of agile earth observation satellite missions

    NASA Astrophysics Data System (ADS)

    Hahn, M.; Müller, T.; Levenhagen, J.

    2014-12-01

    Agile earth observation satellite missions are becoming more and more important due to their capability to perform fast reorientation maneuvers with 3 degrees of freedom to capture different target areas along the orbital path, thus increasing the observed area and complexity of scans. The design of an agile earth observation satellite mission is a non-trivial task due to the fact that a trade-off between observed area and complexity of the scans on the one hand and degree of agility available and thus performance of the attitude control devices on the other hand has to be done. Additionally, the designed mission has to be evaluated in a realistic environment also taking into account the specific characteristics of the chosen actuators. In the present work, several methods are combined to provide an integrated analysis of agile earth observation satellite missions starting from the definition of a desired ground scan scenario, going via the creation of a guidance profile to a realistic simulation and ending at the verification of the feasibility by detailed closed-loop simulation. Regarding its technical implementation at Astrium GmbH, well-proven tools for the different tasks of the analysis are incorporated and well defined interfaces for those tools are specified, allowing a high degree of automatism and thus saving time and minimizing errors. This results in a complete end-to-end process for the design, analysis and verification of agile earth observation satellite missions. This process is demonstrated by means of an example analysis using control moment gyros for a high agility mission.

  20. Earth gravity model improvement - An alternative method for Doppler-tracked satellites

    NASA Astrophysics Data System (ADS)

    Lansard, E.; Biancale, R.

    A new method of earth gravity model improvement based on an analytical formulation of Doppler residuals is presented here in prospect of future geodetic and altimetric missions (DORIS< TOPEX/POSEIDON, ERS1). After an intermediate step of orbit improvement, disturbing forces due to gravity field mismodeling are recovered above tracking statins at satellite altitude. Some significant simulation results for Seasat and DORIS are presented.

  1. Instrument constraints and interface specifications. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The equipment specifications for the thematic mapper and high resolution pointable imager for use on the Earth Observatory Satellite (EOS) are presented. The interface requirements of the systems are defined. The interface requirements are extracted from the equipment specifications and are intended as a summary to be used by the system and spacecraft designer. The appropriate documentation from which the specifications of the equipment are established are identified.

  2. Earth Observatory Satellite system definition study. Report no. 4: Management approach recommendations

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A management approach for the Earth Observatory Satellite (EOS) which will meet the challenge of a constrained cost environment is presented. Areas of consideration are contracting techniques, test philosophy, reliability and quality assurance requirements, commonality options, and documentation and control requirements. The various functional areas which were examined for cost reduction possibilities are identified. The recommended management approach is developed to show the primary and alternative methods.

  3. Comparison of three techniques for modeling the Earth's gravity field on the basis of a satellite orbit

    NASA Astrophysics Data System (ADS)

    Ditmar, P.; van Eck van der Sluijs, A.

    2003-12-01

    At present, there are three techniques for the computation of the Earth's gravity field from a satellite orbit: (i) the "classical" approach based on the integration of variational equations (IVEA); (ii) the energy balance approach (EBA); (iii) the acceleration approach (AA), which directly relates the satellite accelerations to the gravity field in accordance with Newton's second law. Most of the results have been obtained so far with the IVEA and EBA. The AA is believed to be inferior because the double differentiation needed to convert the satellite orbit into the satellite accelerations amplifies data noise dramatically. We show that that a poor performance of the AA is a myth. One can easily prove that the solution of an inverse problem is invariant with respect to the linear transformation of the data vector of the kind d' = B d (where d is the original data vector, d' is the transformed data vector, and B is the transformation matrix) provided that the matrix B is square and invertible. The only pre-requisite is that the optimal estimation procedure is followed, including the usage of the properly transformed covariance matrix: Cd' = B Cd BT. In other words, such data vectors d' and d are equivalent. It is easy to show that the satellite positions and satellite accelerations are two nearly equivalent data sets (in order to reach a strict equivalence, the latter can be supplied, e.g., with the initial state vector). Therefore, these data sets may result in nearly the same gravity field model. A decision which technique is preferable should be made on the basis of practical considerations, e.g. the numerical efficiency. According to our experience, the AA leads to a much faster computational scheme than the IVEA. Furthermore, we have considered the EBA. It is easy to show that a set of kinetic energy measurements is nearly equivalent to a set of along-track satellite accelerations. The other two components of the acceleration vectors are ignored by the EBA

  4. A Topology Control Strategy with Reliability Assurance for Satellite Cluster Networks in Earth Observation.

    PubMed

    Chen, Qing; Zhang, Jinxiu; Hu, Ze

    2017-02-23

    This article investigates the dynamic topology control problemof satellite cluster networks (SCNs) in Earth observation (EO) missions by applying a novel metric of stability for inter-satellite links (ISLs). The properties of the periodicity and predictability of satellites' relative position are involved in the link cost metric which is to give a selection criterion for choosing the most reliable data routing paths. Also, a cooperative work model with reliability is proposed for the situation of emergency EO missions. Based on the link cost metric and the proposed reliability model, a reliability assurance topology control algorithm and its corresponding dynamic topology control (RAT) strategy are established to maximize the stability of data transmission in the SCNs. The SCNs scenario is tested through some numeric simulations of the topology stability of average topology lifetime and average packet loss rate. Simulation results show that the proposed reliable strategy applied in SCNs significantly improves the data transmission performance and prolongs the average topology lifetime.

  5. Human factors dimensions in the evolution of increasingly automated control rooms for near-earth satellites

    NASA Technical Reports Server (NTRS)

    Mitchell, C. M.

    1982-01-01

    The NASA-Goddard Space Flight Center is responsible for the control and ground support for all of NASA's unmanned near-earth satellites. Traditionally, each satellite had its own dedicated mission operations room. In the mid-seventies, an integration of some of these dedicated facilities was begun with the primary objective to reduce costs. In this connection, the Multi-Satellite Operations Control Center (MSOCC) was designed. MSOCC represents currently a labor intensive operation. Recently, Goddard has become increasingly aware of human factors and human-machine interface issues. A summary is provided of some of the attempts to apply human factors considerations in the design of command and control environments. Current and future activities with respect to human factors and systems design are discussed, giving attention to the allocation of tasks between human and computer, and the interface for the human-computer dialogue.

  6. Handover aspects for a Low Earth Orbit (LEO) CDMA Land Mobile Satellite (LMS) system

    NASA Astrophysics Data System (ADS)

    Carter, P.; Beach, M. A.

    This paper addresses the problem of handoff in a land mobile satellite (LMS) system between adjacent satellites in a low earth orbit (LEO) constellation. In particular, emphasis is placed on the application of soft handoff in a direct sequence code division multiple access (DS-CDMA) LMS system. Soft handoff is explained in terms of terrestrial macroscopic diversity, in which signals transmitted via several independent fading paths are combined to enhance the link quality. This concept is then reconsidered in the context of a LEO LMS system. A two-state Markov channel model is used to simulate the effects of shadowing on the communications path from the mobile to each satellite during handoff. The results of the channel simulation form a platform for discussion regarding soft handoff, highlighting the potential merits of the scheme when applied in a LEO LMS environment.

  7. An evaluation of radiation damage to solid state components flown in low earth orbit satellites.

    PubMed

    Shin, Myung-Won; Kim, Myung-Hyun

    2004-01-01

    The effects of total ionising radiation dose upon commercial off-the-shelf semiconductors fitted to satellites operating in low Earth orbit (LEO) conditions was evaluated. The evaluation was performed for the Korea Institute of Technology SATellite-1, (KITSAT-1) which was equipped with commercial solid state components. Two approximate calculation models for space radiation shielding were developed. Verification was performed by comparing the results with detailed three-dimensional calculations using the Monte-Carlo method and measured data from KITSAT-1. It was confirmed that the developed approximate models were reliable for satellite shielding calculations. It was also found that commercial semiconductor devices, which were not radiation hardened, could be damaged within their lifetime due to the total ionising dose they are subject to in the LEO environment. To conclude, an intensive shielding analysis should be considered when commercial devices are used.

  8. Handover aspects for a Low Earth Orbit (LEO) CDMA Land Mobile Satellite (LMS) system

    NASA Technical Reports Server (NTRS)

    Carter, P.; Beach, M. A.

    1993-01-01

    This paper addresses the problem of handoff in a land mobile satellite (LMS) system between adjacent satellites in a low earth orbit (LEO) constellation. In particular, emphasis is placed on the application of soft handoff in a direct sequence code division multiple access (DS-CDMA) LMS system. Soft handoff is explained in terms of terrestrial macroscopic diversity, in which signals transmitted via several independent fading paths are combined to enhance the link quality. This concept is then reconsidered in the context of a LEO LMS system. A two-state Markov channel model is used to simulate the effects of shadowing on the communications path from the mobile to each satellite during handoff. The results of the channel simulation form a platform for discussion regarding soft handoff, highlighting the potential merits of the scheme when applied in a LEO LMS environment.

  9. SatelliteDL - An IDL Toolkit for the Analysis of Satellite Earth Observations - GOES, MODIS, VIIRS and CERES

    NASA Astrophysics Data System (ADS)

    Fillmore, D. W.; Galloy, M. D.; Kindig, D.

    2013-12-01

    SatelliteDL is an IDL toolkit for the analysis of satellite Earth observations from a diverse set of platforms and sensors. The design features an abstraction layer that allows for easy inclusion of new datasets in a modular way. The core function of the toolkit is the spatial and temporal alignment of satellite swath and geostationary data. IDL has a powerful suite of statistical and visualization tools that can be used in conjunction with SatelliteDL. Our overarching objective is to create utilities that automate the mundane aspects of satellite data analysis, are extensible and maintainable, and do not place limitations on the analysis itself. Toward this end we have constructed SatelliteDL to include (1) HTML and LaTeX API document generation, (2) a unit test framework, (3) automatic message and error logs, (4) HTML and LaTeX plot and table generation, and (5) several real world examples with bundled datasets available for download. For ease of use, datasets, variables and optional workflows may be specified in a flexible format configuration file. Configuration statements may specify, for example, a region and date range, and the creation of images, plots and statistical summary tables for a long list of variables. SatelliteDL enforces data provenance; all data should be traceable and reproducible. The output NetCDF file metadata holds a complete history of the original datasets and their transformations, and a method exists to reconstruct a configuration file from this information. Release 0.1.0 of SatelliteDL is anticipated for the 2013 Fall AGU conference. It will distribute with ingest methods for GOES, MODIS, VIIRS and CERES radiance data (L1) as well as select 2D atmosphere products (L2) such as aerosol and cloud (MODIS and VIIRS) and radiant flux (CERES). Future releases will provide ingest methods for ocean and land surface products, gridded and time averaged datasets (L3 Daily, Monthly and Yearly), and support for 3D products such as temperature and

  10. High-resolution sensing for precision agriculture: from Earth-observing satellites to unmanned aerial vehicles

    NASA Astrophysics Data System (ADS)

    McCabe, Matthew F.; Houborg, Rasmus; Lucieer, Arko

    2016-10-01

    With global population projected to approach 9 billion by 2050, it has been estimated that a 40% increase in cereal production will be required to satisfy the worlds growing nutritional demands. Any such increases in agricultural productivity are likely to occur within a system that has limited room for growth and in a world with a climate that is different from that of today. Fundamental to achieving food and water security, is the capacity to monitor the health and condition of agricultural systems. While space-agency based satellites have provided the backbone for earth observation over the last few decades, many developments in the field of high-resolution earth observation have been advanced by the commercial sector. These advances relate not just to technological developments in the use of unmanned aerial vehicles (UAVs), but also the advent of nano-satellite constellations that offer a radical shift in the way earth observations are now being retrieved. Such technologies present opportunities for improving our description of the water, energy and carbon cycles. Efforts towards developing new observational techniques and interpretative frameworks are required to provide the tools and information needed to improve the management and security of agricultural and related sectors. These developments are one of the surest ways to better manage, protect and preserve national food and water resources. Here we review the capabilities of recently deployed satellite systems and UAVs and examine their potential for application in precision agriculture.

  11. New Construction KU-Band Antenna with Improved Radiation Diagram for Satellite Broadcasting Receiving Earth Station

    NASA Astrophysics Data System (ADS)

    Petkov, Peter; Alexandrova, Alissaveta

    2013-12-01

    The development of a new design small offset antenna with elliptical aperture equivalent to about 60 cm circular aperture intended for receiving earth stations in the band 11.7-12.5 GHz of Broadcasting Satellite Service (BSS) is reported in the paper. The antenna mechanical and electrical characteristics are presented. The main antenna feature is the improved antenna radiation pattern in the plane of the geostationary satellite orbit (GSO) compared to the reference antenna pattern of BSS receiving earth stations in Annex 5 of Appendix 30 of the Radio Regulations (RR) that will contribute to less interference impact between real BSS systems in Ku-band especially systems with satellites located at comparatively closely situated GSO positions. The antenna parameters values achieved in this project are in support of the idea to improve the reference antenna pattern of the BSS earth stations that will contribute to more efficient use of the frequency spectrum-orbital resources in this band corresponding to the wording of Article 44 of the Constitution of the International Telecommunication Union (ITU) and the main principle of the RR for equitable access to frequency spectrum and GSO.

  12. International two-way satellite time transfers using INTELSAT space segment and small Earth stations

    NASA Technical Reports Server (NTRS)

    Veenstra, Lester B.

    1990-01-01

    The satellite operated by the International Telecommunications Satellite Organization (INTELSAT) provides new and unique capabilities for the coordinates of international time scales on a world wide basis using the two-way technique. A network of coordinated clocks using small earth stations collocated with the scales is possible. Antennas as small as 1.8 m at K-band and 3 m at C-band transmitting powers of less than 1 W will provide signals with time jitters of less than 1 ns existing spread spectrum modems. One way time broadcasting is also possible, under the INTELSAT INTELNET system, possibly using existing international data distribution (press and financial) systems that are already operating spread spectrum systems. The technical details of the satellite and requirements on satellite earth stations are given. The resources required for a regular operational international time transfer service are analyzed with respect to the existing international digital service offerings of the INTELSAT Business Service (IBS) and INTELNET. Coverage areas, typical link budgets, and a summary of previous domestic and international work using this technique are provided. Administrative procedures for gaining access to the space segment are outlined. Contact information for local INTELSAT signatories is listed.

  13. Constellation design for earth observation based on the characteristics of the satellite ground track

    NASA Astrophysics Data System (ADS)

    Luo, Xin; Wang, Maocai; Dai, Guangming; Song, Zhiming

    2017-04-01

    This paper responds to the increasing need for Earth observation missions and deals with the design of Repeating Sun-Synchronous Constellations (RSSCs) which takes into consideration of constellations composed of one or more orbital planes. Based on the mature design approach of Repeating Sun-synchronous orbits, a novel technique to design RSSCs is presented, which takes the second gravitational zonal harmonic into consideration. In order to obtain regular cycles of observation of the Earth by a single satellite, the orbital relationships have to be satisfied firstly are illustrated. Then, by making full analyses of the characteristics of the satellite ground track, orbital parameters are properly calculated to make other satellites pass on the same or different ground track of the single satellite. Last, single-plane or multi-plane constellations are used to improve the repetitions of the observation and the ground resolution. RSSCs allow observing the same region once at the same local time in a solar day and several times at the different local time in a solar day. Therefore, this kind of constellations meets all requirements for the remote sensing applications, which need to observe the same region under the same or different visible conditions. Through various case studies, the calculation technique is successfully demonstrated.

  14. A time variable model of Earth's albedo. [for climatology studies and interpretation of satellite data

    NASA Technical Reports Server (NTRS)

    Bartman, F. L.

    1980-01-01

    A time variable model of Earth's albedo was prepared for use in climate studies and as an aid to the interpretation of satellite Earth radiation budget data. The features of the model include: a 10 deg latitude 10 deg longitude grid for numerical integration, surface albedo specified at 1 month intervals, calculation of zenith angle effect for surface albedo and of the additional effect of the atmosphere on the albedo. Percent cloud cover is specified for 29 different climatological cloud type regions at 8 times of the day for 12 months of the year. Cloud albedos were specified for each of the cloud climatological types. Diurnal and monthly variations of this model are described and results are compared with a model which is based on satellite measurements. A computer program was also written for use in studying the sampling effects in satellite radiation budget measurements. An example of the results of calculations with this program are compared with a previous study of the sampling effects. This program for satellite orbit characteristics is to be combined with the time-variable albedo model for further study of the sampling problem.

  15. International two-way satellite time transfers using INTELSAT space segment and small Earth stations

    NASA Astrophysics Data System (ADS)

    Veenstra, Lester B.

    1990-05-01

    The satellite operated by the International Telecommunications Satellite Organization (INTELSAT) provides new and unique capabilities for the coordinates of international time scales on a world wide basis using the two-way technique. A network of coordinated clocks using small earth stations collocated with the scales is possible. Antennas as small as 1.8 m at K-band and 3 m at C-band transmitting powers of less than 1 W will provide signals with time jitters of less than 1 ns existing spread spectrum modems. One way time broadcasting is also possible, under the INTELSAT INTELNET system, possibly using existing international data distribution (press and financial) systems that are already operating spread spectrum systems. The technical details of the satellite and requirements on satellite earth stations are given. The resources required for a regular operational international time transfer service are analyzed with respect to the existing international digital service offerings of the INTELSAT Business Service (IBS) and INTELNET. Coverage areas, typical link budgets, and a summary of previous domestic and international work using this technique are provided. Administrative procedures for gaining access to the space segment are outlined. Contact information for local INTELSAT signatories is listed.

  16. SERB, a nano-satellite dedicated to the Earth-Sun relationship

    NASA Astrophysics Data System (ADS)

    Meftah, Mustapha; Bamas, Étienne; Cambournac, Pierre; Cherabier, Philippe; Demarets, Romain; Denis, Gaspard; Dion, Axel; Duroselle, Raphaël.; Duveiller, Florence; Eichner, Laetitia; Lozeve, Dimitri; Mestdagh, Guillaume; Ogier, Antoine; Oliverio, Romane; Receveur, Thibault; Souchet, Camille; Gilbert, Pierre; Poiet, Germain; Hauchecorne, Alain; Keckhut, Philippe; Sarkissian, Alain

    2016-05-01

    The Solar irradiance and Earth Radiation Budget (SERB) mission is an innovative proof-of-concept nano-satellite, with three ambitious scientific objectives. The nano-satellite aims at measuring on the same platform the absolute value of the total solar irradiance (TSI) and its variability, the ultraviolet (UV) solar spectral variability, and the different components of the Earth radiation budget. SERB is a joint project between CNES (Centre National d'Etudes Spatiales), Ecole polytechnique, and LATMOS (Laboratoire Atmospheres, Milieux, Observations Spatiales) scheduled for a launch in 2020-2021. It is a three-unit CubeSat (X-CubeSat II), developed by students from ´Ecole polytechnique. Critical components of instrumental payloads of future large missions (coatings, UV filters, etc.) can acquire the technical maturity by flying in a CubeSat. Nano-satellites also represent an excellent alternative for instrumentation testing, allowing for longer flights than rockets. More-over, specific scientific experiments can be performed by nano-satellites. This paper is intended to present the SERB mission and its scientific objectives.

  17. The effect of lunarlike satellites on the orbital infrared light curves of Earth-analog planets.

    PubMed

    Moskovitz, Nicholas A; Gaidos, Eric; Williams, Darren M

    2009-04-01

    We have investigated the influence of lunarlike satellites on the infrared orbital light curves of Earth-analog extrasolar planets. Such light curves will be obtained by NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions as a consequence of repeat observations to confirm the companion status of a putative planet and determine its orbit. We used an energy balance model to calculate disk-averaged infrared (bolometric) fluxes from planet-satellite systems over a full orbital period (one year). The satellites are assumed to lack an atmosphere, have a low thermal inertia like that of the Moon, and span a range of plausible radii. The planets are assumed to have thermal and orbital properties that mimic those of Earth, while their obliquities and orbital longitudes of inferior conjunction remain free parameters. Even if the gross thermal properties of the planet can be independently constrained (e.g., via spectroscopy or visible-wavelength detection of specular glint from a surface ocean), only the largest (approximately Mars-sized) lunarlike satellites can be detected by light curve data from a TPF-like instrument (i.e., one that achieves a photometric signal-to-noise ratio of 10 to 20 at infrared wavelengths). Nondetection of a lunarlike satellite can obfuscate the interpretation of a given system's infrared light curve so that it may resemble a single planet with high obliquity, different orbital longitude of vernal equinox relative to inferior conjunction, and in some cases drastically different thermal characteristics. If the thermal properties of the planet are not independently established, then the presence of a lunarlike satellite cannot be inferred from infrared data, which would thus demonstrate that photometric light curves alone can only be used for preliminary study, and the addition of spectroscopic data will be necessary.

  18. Data Dissemination System Status and Plan for Jaxa's Earth Observation Satellite Data

    NASA Astrophysics Data System (ADS)

    Fuda, M.; Miura, S.

    2012-12-01

    1. INTRODUCTION JAXA is Japan's national aerospace agency and responsible for research, technology development and the launch of satellites into orbit, and is involved in many more advanced missions, such as asteroid exploration and possible manned exploration of the Moon. Since 1978, JAXA started to disseminate earth observation data acquired by satellites to researchers and those data scene became more than two Million scenes in 2011. This paper focuses on the status and future plan for JAXA's Data Dissemination System for those data. 2. STATUS JAXA is Japan's national aerospace agency and responsible for research, technology development and the launch of satellites into orbit. In October 1978, JAXA opened the Earth Observation Center (EOC) and started to archive and disseminate earth observation data acquired by multiple satellites. 2.1. Target data Currently, the disseminated data includes "JAXA's satellite/sensor data" and "non-JAXA's satellite/sensor data", as shown in Table 2-1. In 2011, the total disseminated data scene became more than two Million scenes. 2.2. Data Dissemination Guideline The JAXA basic data dissemination guideline is a free for researchers and specific agencies. JAXA has two approaches for dissemination. One is that the data is distributed for specific agencies by Mission Operation Systems (MOS). Each project has its own MOS, for example, GCOM-W1 has a GCOM-W1 MOS. Another is that the data is disseminated for many researchers by Data Distribution Systems. Now JAXA has three Data Distribution systems, EOIS, AUIG and GCOM-W1DPSS. Table 2-1 : Disseminated earth observation data from JAXA's facility Satellite Sensor Processing Level ALOS AVNIR-2 Level 1 PRISM Level 1 PALSAR Level 1 TRMM PR Level 1, 2, 3 CMB Level 1, 2, 3 TMI Level 1, 2, 3 VIR Level 1, 2, 3 Aqua AMSR-E Level 1, 2, 3 ADEOS-II AMSR Level 1, 2, 3 GLI-1km Level 1, 2, 3 GLI-250m Level 1, 2, 3 JERS-1 OSW Level 0, 1, 2 OVN Level 0, 1, 2, 5 SAR Level 1, 2 ADEOS AVNIR Level 1 OCTS

  19. Looking Down on the Earth: How Satellites Have Revolutionized Our Understanding of Our Home Planet

    NASA Astrophysics Data System (ADS)

    Freilich, Michael

    2016-04-01

    Earth is a complex, dynamic system we do not yet fully understand. The Earth system, like the human body, comprises diverse components that interact in complex ways. We need to understand the Earth's atmosphere, lithosphere, hydrosphere, cryosphere, and biosphere as a single connected system. Our planet is changing on all spatial and temporal scales. This presentation will highlight how satellite observations are revolutionizing our understanding of and its response to natural or human-induced changes, and to improve prediction of climate, weather, and natural hazards. Bio: MICHAEL H. FREILICH, Director of the Earth Science Division, Science Mission Directorate at NASA Headquarters. Prior to NASA, he was a Professor and Associate Dean in the College of Oceanic and Atmospheric Sciences at Oregon State University. He received Ph.D. in Oceanography from Scripps Institution of Oceanography (Univ. of CA., San Diego) in 1982. Dr. Freilich's research focuses on the determination, validation, and geophysical analysis of ocean surface wind velocity measured by satellite-borne microwave radar and radiometer instruments. He has developed scatterometer and altimeter wind model functions, as well as innovative validation techniques for accurately quantifying the accuracy of spaceborne environmental measurements. Dr. Freilich has served on many NASA, National Research Council (NRC), and research community advisory and steering groups, including the WOCE Science Steering Committee, the NASA EOS Science Executive Committee, the NRC Ocean Studies Board, and several NASA data system review committees. Freilich's non-scientific passions include nature photography and soccer refereeing at the youth, high school, and adult levels.

  20. Satellites Seek Gravity Signals for Remote Sensing the Seismotectonic Stresses in Earth

    NASA Technical Reports Server (NTRS)

    Liu, Han-Shou; Chen, Jizhong; Li, Jinling

    2003-01-01

    The ability of the mantle to withstand stress-difference due to superimposed loads would appear to argue against flow in the Earth s mantle, but the ironic fact is that the satellite determined gravity variations are the evidence of density differences associated with mantle flow. The type of flow which is most likely to be involved concerns convection currents. For the past 4 decades, models of mantle convection have made remarkable advancements. Although a large body of evidence regarding the seafloor depth, heat flow, lithospheric strength and forces of slab-pull and swell-push has been obtained, the global seismotectonic stresses in the Earth are yet to be determined. The problem is that no one has been able to come up with a satisfactory scenario that must characterize the stresses in the Earth which cause earthquakes and create tectonic features.

  1. Contingency study for the third international Sun-Earth Explorer (ISEE-3) satellite

    NASA Technical Reports Server (NTRS)

    Dunham, D. W.

    1979-01-01

    The third satellite of the international Sun-Earth Explorer program was inserted into a periodic halo orbit about L sub 1, the collinear libration point between the Sun and the Earth-Moon barycenter. A plan is presented that was developed to enable insertion into the halo orbit in case there was a large underperformance of the Delta second or third stage during the maneuver to insert the spacecraft into the transfer trajectory. After one orbit of the Earth, a maneuver would be performed near perigee to increase the energy of the orbit. A relatively small second maneuver would put the spacecraft in a transfer trajectory to the halo orbit, into which it could be inserted for a total cost within the fuel budget. Overburns (hot transfer trajectory insertions) were also studied.

  2. The earth's gravitational field from the combination of satellite and terrestrial data

    NASA Technical Reports Server (NTRS)

    Rapp, R. H.

    1973-01-01

    This paper reviews techniques and results in the combination of gravimetric and satellite data. The estimation of mean anomalies for use in combination studies is discussed with the location of current gravity material being described. Specific techniques for combination solutions are discussed for various models. These models include those where the gravitational field is represented by a set of potential coefficients, or by a set of discrete blocks distributed on the earth. The potential coefficient solutions compared are those of the SAO Standard Earth II and III, the Goddard Earth Model 4, and a solution by the author. These solutions are compared in terms of coefficients, undulation and anomaly differences, and implied anomaly degree variances. In addition, comparisons were made through terrestrial anomaly comparisons, astrogeodetic undulation comparisons, and orbit fitting tests.

  3. On the use of wavelet for extracting feature patterns from Multitemporal google earth satellite data sets

    NASA Astrophysics Data System (ADS)

    Lasaponara, R.

    2012-04-01

    The great amount of multispectral VHR satellite images, even available free of charge in Google earth has opened new strategic challenges in the field of remote sensing for archaeological studies. These challenges substantially deal with: (i) the strategic exploitation of satellite data as much as possible, (ii) the setting up of effective and reliable automatic and/or semiautomatic data processing strategies and (iii) the integration with other data sources from documentary resources to the traditional ground survey, historical documentation, geophysical prospection, etc. VHR satellites provide high resolution data which can improve knowledge on past human activities providing precious qualitative and quantitative information developed to such an extent that currently they share many of the physical characteristics of aerial imagery. This makes them ideal for investigations ranging from a local to a regional scale (see. for example, Lasaponara and Masini 2006a,b, 2007a, 2011; Masini and Lasaponara 2006, 2007, Sparavigna, 2010). Moreover, satellite data are still the only data source for research performed in areas where aerial photography is restricted because of military or political reasons. Among the main advantages of using satellite remote sensing compared to traditional field archaeology herein we briefly focalize on the use of wavelet data processing for enhancing google earth satellite data with particular reference to multitemporal datasets. Study areas selected from Southern Italy, Middle East and South America are presented and discussed. Results obtained point out the use of automatic image enhancement can successfully applied as first step of supervised classification and intelligent data analysis for semiautomatic identification of features of archaeological interest. Reference Lasaponara R, Masini N (2006a) On the potential of panchromatic and multispectral Quickbird data for archaeological prospection. Int J Remote Sens 27: 3607-3614. Lasaponara R

  4. Precise Ground-In-the-Loop Orbit Control for Low Earth Observation Satellites

    NASA Astrophysics Data System (ADS)

    Arbinger, C.; D'Amico, S.; Eineder, M.

    The growing interest in earth observation missions equipped with space-borne optical and synthetic aperture radar (SAR) sensors drives the accuracy requirements with respect to orbit determination and control. Especially SAR interferometry with its capability to resolve the velocity of on-ground objects (e.g. for traffic monitoring, ocean currents and glacier monitoring) and to determine highly precise digital elevation models is of significant interest for scientific applications. These goals may be achieved using along-track and repeat-pass interferometry with a satellite formation, based on the precise orbit control of one satellite with respect to the osculating trajectory of the second satellite. Such a control concept will be realized by the German TerraSAR-X mission, with an expected launch in 2006, using a virtual formation, where a single satellite will be controlled in a tight manner with respect to a predefined osculating reference trajectory. This is very challenging, since common orbit disturbances, like for close twin formations, do not cancel out in this scenario. The predefined trajectory in the TerraSAR-X case could also be the orbit of a second satellite. The paper describes the generation of such a virtual reference orbit, discusses the ground-in-the-loop control concept and presents results from a long-term simulation.

  5. Measurement of the Earth-Observer-1 Satellite X-Band Phased Array

    NASA Technical Reports Server (NTRS)

    Perko, Kenneth; Dod, Louis; Demas, John

    2003-01-01

    The recent launch and successful orbiting of the EO-1 Satellite has provided an opportunity to validate the performance of a newly developed X-Band transmit-only phased array aboard the satellite. This paper will compare results of planar near-field testing before and after spacecraft installation as well as on-orbit pattern characterization. The transmit-only array is used as a high data rate antenna for relaying scientific data from the satellite to earth stations. The antenna contains distributed solid-state amplifiers behind each antenna element that cannot be monitored except for radiation pattern measurements. A unique portable planar near-field scanner allows both radiation pattern measurements and also diagnostics of array aperture distribution before and after environmental testing over the ground-integration and prelaunch testing of the satellite. The antenna beam scanning software was confirmed from actual pattern measurements of the scanned beam positions during the spacecraft assembly testing. The scanned radiation patterns on-orbit were compared to the near-field patterns made before launch to confirm the antenna performance. The near-field measurement scanner has provided a versatile testing method for satellite high gain data-link antennas.

  6. Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2007-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  7. Method and associated apparatus for capturing, servicing, and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2009-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  8. Method and associated apparatus for capturing, servicing and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2008-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  9. Method and associated apparatus for capturing, servicing and de-orbiting earth satellites using robotics

    NASA Technical Reports Server (NTRS)

    Cepollina, Frank J. (Inventor); Burns, Richard D. (Inventor); Holz, Jill M. (Inventor); Corbo, James E. (Inventor); Jedhrich, Nicholas M. (Inventor)

    2007-01-01

    This invention is a method and supporting apparatus for autonomously capturing, servicing and de-orbiting a free-flying spacecraft, such as a satellite, using robotics. The capture of the spacecraft includes the steps of optically seeking and ranging the satellite using LIDAR; and matching tumble rates, rendezvousing and berthing with the satellite. Servicing of the spacecraft may be done using supervised autonomy, which is allowing a robot to execute a sequence of instructions without intervention from a remote human-occupied location. These instructions may be packaged at the remote station in a script and uplinked to the robot for execution upon remote command giving authority to proceed. Alternately, the instructions may be generated by Artificial Intelligence (AI) logic onboard the robot. In either case, the remote operator maintains the ability to abort an instruction or script at any time, as well as the ability to intervene using manual override to teleoperate the robot.In one embodiment, a vehicle used for carrying out the method of this invention comprises an ejection module, which includes the robot, and a de-orbit module. Once servicing is completed by the robot, the ejection module separates from the de-orbit module, leaving the de-orbit module attached to the satellite for de-orbiting the same at a future time. Upon separation, the ejection module can either de-orbit itself or rendezvous with another satellite for servicing. The ability to de-orbit a spacecraft further allows the opportunity to direct the landing of the spent satellite in a safe location away from population centers, such as the ocean.

  10. A line rate calculation method for arbitrary directional imaging of an Earth observing satellite

    NASA Astrophysics Data System (ADS)

    Jeon, Moon-Jin; Kim, Eunghyun; Lim, Seong-Bin; Choi, Seok-Weon

    2016-10-01

    For an earth observing satellite, a line rate is the number of lines which the CCD of push broom type camera scans in a second. It can be easily calculated by ground velocity divided by ground sample distance. Accurate calculation of line rate is necessary to obtain high quality image using TDI CCD. The earth observing satellite has four types of imaging missions which are strip imaging, stereo imaging, multi-point imaging, and arbitrary directional imaging. For the first three types of imaging, ground scanning direction is aligned with satellite velocity direction. Therefore, if the orbit propagation and spacecraft attitude information are available, the ground velocity and ground sample distance could be easily calculated. However, the calculation method might not be applicable to the arbitrary directional imaging. In the arbitrary directional imaging mode, the ground velocity is not fixed value which could be directly derived by orbit information. Furthermore, the ground sample distance might not be easily calculated by simple trigonometry which is possible for the other types of imaging. In this paper, we proposed a line rate calculation method for the arbitrary directional imaging. We applied spherical geometry to derive the equation of ground point which is the intersection between the line of sight vector of the camera and earth surface. The derivative of this equation for time is the ground velocity except the factor of earth rotation. By adding this equation and earth rotation factor, the true ground velocity vector could be derived. For the ground sample distance, we applied the equation of circle and ellipse for yaw angle difference. The equation of circle is used for the yaw angle representation on the plane which is orthogonal to the line of sight vector. The equation of ellipse is used for the yaw angle representation on the ground surface. We applied the proposed method to the KOMPSAT-3A (Korea Multi-Purpose Satellite 3A) mission which is the first

  11. Remote Sensing Education and Development Countries: Multilateral Efforts through the Committee on Earth Observation Satellites (CEOS)

    NASA Technical Reports Server (NTRS)

    Charles, Leslie Bermann

    1998-01-01

    The Committee on Earth Observation Satellites (CEOS) is an international organization which coordinates space-based Earth observations world wide. Created in 1984, CEOS now comprises 38 national space agencies, regional organizations and international space-related and research groups. The aim of CEOS is to achieve international coordination in the planning of satellite missions for Earth observation and to maximize the utilization of data from these missions world-wide. With regard to developing countries, the fundamental aim of CEOS is to encourage the creation and maintenance of indigenous capability that is integrated into the local decision-making process, thereby enabling developing countries to obtain the maximum benefit from Earth observation. Obtaining adequate access to remote sensing information is difficult for developing countries and students and teachers alike. High unit data prices, the specialized nature of the technology , difficulty in locating specific data, complexities of copyright provisions, the emphasis on "leading edge" technology and research, and the lack of training materials relating to readily understood application are frequently noted obstacles. CEOS has developed an education CD-ROM which is aimed at increasing the integration of space-based data into school curricula, meeting the heretofore unsatisfied needs of developing countries for information about Earth observation application, data sources and future plans; and raising awareness around the world of the value of Earth observation data from space. The CD-ROM is designed to be used with an Internet web browser, increasing the information available to the user, but it can also be used on a stand-alone machine. It contains suggested lesson plans and additional resources for educators and users in developing countries.

  12. Artificial biospheres as a model for global ecology on planet Earth.

    PubMed

    Allen, J

    2000-01-01

    Artificial biospheres of the scale and complexity of Biosphere 2 can only work with coordinated rigorous design at each level of ecology: biospheres, biomes, bioregions, ecosystems, communities, patches, phases, physical-chemical functions, guilds, populations, organisms, and cells (both eucaryotic and procaryotic). This article reviews these theoretical concepts and provides examples of how this structure was applied to the design and development of Biosphere 2. In addition to this ecological engineering design, the addition of humans as inhabitants in the closed system required design of ethnological patterns and of technical and cybernetic systems for meeting specifically human requirements of labor efficiency, climate, nutrition, wastewater recycle, and pure air and water. Ecological levels of biospheric complexity can be directly applied to studies of the Earth's biosphere and, in fact, must be used to understand complex biospheric processes.

  13. Mott Electrons in an Artificial Graphenelike Crystal of Rare-Earth Nickelate S.

    SciTech Connect

    Middey, Srimanta; Meyers, Derek J.; Doennig, D.; Kareev, M; Liu, Xiaoran; Cao, Yanwei; Yang, Zhenzhong; Shi, Jinan; Gu, Lin; Ryan, Philip J.; Freeland, J. W.; Pentcheva, R.; Chakhalian, J.

    2016-02-05

    Deterministic control over the periodic geometrical arrangement of the constituent atoms is the backbone of the material properties, which, along with the interactions, define the electronic and magnetic ground state. Following this notion, a bilayer of a prototypical rare-earth nickelate, NdNiO3, combined with a dielectric spacer, LaAlO3, has been layered along the pseudocubic [111] direction. The resulting artificial graphenelike Mott crystal with magnetic 3d electrons has antiferromagnetic correlations. In addition, a combination of resonant X-ray linear dichroism measurements and ab initio calculations reveal the presence of an ordered orbital pattern, which is unattainable in either bulk nickelates or nickelate based heterostructures grown along the [001] direction. These findings highlight another promising venue towards designing new quantum many-body states by virtue of geometrical engineering.

  14. Mott Electrons in an Artificial Graphenelike Crystal of Rare-Earth Nickelate.

    PubMed

    Middey, S; Meyers, D; Doennig, D; Kareev, M; Liu, X; Cao, Y; Yang, Zhenzhong; Shi, Jinan; Gu, Lin; Ryan, P J; Pentcheva, R; Freeland, J W; Chakhalian, J

    2016-02-05

    Deterministic control over the periodic geometrical arrangement of the constituent atoms is the backbone of the material properties, which, along with the interactions, define the electronic and magnetic ground state. Following this notion, a bilayer of a prototypical rare-earth nickelate, NdNiO_{3}, combined with a dielectric spacer, LaAlO_{3}, has been layered along the pseudocubic [111] direction. The resulting artificial graphenelike Mott crystal with magnetic 3d electrons has antiferromagnetic correlations. In addition, a combination of resonant X-ray linear dichroism measurements and ab initio calculations reveal the presence of an ordered orbital pattern, which is unattainable in either bulk nickelates or nickelate based heterostructures grown along the [001] direction. These findings highlight another promising venue towards designing new quantum many-body states by virtue of geometrical engineering.

  15. Establishing the Antarctic Dome C community reference standard site towards consistent measurements from Earth observation satellites

    USGS Publications Warehouse

    Cao, C.; Uprety, S.; Xiong, J.; Wu, A.; Jing, P.; Smith, D.; Chander, G.; Fox, N.; Ungar, S.

    2010-01-01

    Establishing satellite measurement consistency by using common desert sites has become increasingly more important not only for climate change detection but also for quantitative retrievals of geophysical variables in satellite applications. Using the Antarctic Dome C site (75°06′S, 123°21′E, elevation 3.2 km) for satellite radiometric calibration and validation (Cal/Val) is of great interest owing to its unique location and characteristics. The site surface is covered with uniformly distributed permanent snow, and the atmospheric effect is small and relatively constant. In this study, the long-term stability and spectral characteristics of this site are evaluated using well-calibrated satellite instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Preliminary results show that despite a few limitations, the site in general is stable in the long term, the bidirectional reflectance distribution function (BRDF) model works well, and the site is most suitable for the Cal/Val of reflective solar bands in the 0.4–1.0 µm range. It was found that for the past decade, the reflectivity change of the site is within 1.35% at 0.64 µm, and interannual variability is within 2%. The site is able to resolve calibration biases between instruments at a level of ~1%. The usefulness of the site is demonstrated by comparing observations from seven satellite instruments involving four space agencies, including OrbView-2–SeaWiFS, Terra–Aqua MODIS, Earth Observing 1 (EO-1) – Hyperion, Meteorological Operational satellite programme (MetOp) – Advanced Very High Resolution Radiometer (AVHRR), Envisat Medium Resolution Imaging Spectrometer (MERIS) – dvanced Along-Track Scanning Radiometer (AATSR), and Landsat 7 Enhanced Thematic Mapper Plus (ETM+). Dome C is a promising candidate site for climate quality calibration of satellite radiometers towards more consistent satellite measurements, as part

  16. Probability of satellite collision

    NASA Technical Reports Server (NTRS)

    Mccarter, J. W.

    1972-01-01

    A method is presented for computing the probability of a collision between a particular artificial earth satellite and any one of the total population of earth satellites. The collision hazard incurred by the proposed modular Space Station is assessed using the technique presented. The results of a parametric study to determine what type of satellite orbits produce the greatest contribution to the total collision probability are presented. Collision probability for the Space Station is given as a function of Space Station altitude and inclination. Collision probability was also parameterized over miss distance and mission duration.

  17. 78 FR 39200 - Federal Earth Stations-Non-Federal Fixed Satellite Service Space Stations; Spectrum for Non...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-01

    ...This document proposes to make spectrum allocation proposals for three different space related purposes. The Commission makes two alternative proposals to modify the Allocation Table to provide interference protection for Fixed-Satellite Service (FSS) and Mobile- Satellite Service (MSS) earth stations operated by Federal agencies under authorizations granted by the National Telecommunications......

  18. Fundamentals of the route theory for satellite constellation design for Earth discontinuous coverage. Part 2: Synthesis of satellite orbits and constellations

    NASA Astrophysics Data System (ADS)

    Razoumny, Yury N.

    2016-11-01

    The method for synthesis of satellite orbits and constellations, optimized by given criterion (minimum of required number of satellites in the constellation, or minimum revisit time, or minimum of the satellites' swath width required) for fixed parameters of on-board satellite equipment and constraints for unused criterion parameters of a list of mentioned above is presented. The numerical results demonstrate the possibilities of the method developed basing on analyzing the given satellite constellation revisit time values distributed on the Earth coverage area, and for synthesizing the satellite constellations to minimize revisit time in comparison with the traditional approaches based on constellation design in a priori fixed classes used for continuous coverage. Particularly, it is shown that the suggested synthesis method, basing on the simplest type of Route Constellations considered - Secure Route Constellations, directly leads, as result of high speed calculations for given Earth region coverage (seconds, or minutes as a worst case), to the optimized satellite constellations which provide consistently high performance and are better, or at least on the same level, in comparison with the best Walker constellations for discontinuous coverage. In order to have comprehensive coverage picture, both deterministic, and stochastic approaches are considered for estimation of the coverage characteristics of the given region of arbitrary shape, basing on the results of Earth coverage analytic emulation.

  19. A recursively formulated first-order semianalytic artificial satellite theory based on the generalized method of averaging. Volume 1: The generalized method of averaging applied to the artificial satellite problem

    NASA Technical Reports Server (NTRS)

    Mcclain, W. D.

    1977-01-01

    A recursively formulated, first-order, semianalytic artificial satellite theory, based on the generalized method of averaging is presented in two volumes. Volume I comprehensively discusses the theory of the generalized method of averaging applied to the artificial satellite problem. Volume II presents the explicit development in the nonsingular equinoctial elements of the first-order average equations of motion. The recursive algorithms used to evaluate the first-order averaged equations of motion are also presented in Volume II. This semianalytic theory is, in principle, valid for a term of arbitrary degree in the expansion of the third-body disturbing function (nonresonant cases only) and for a term of arbitrary degree and order in the expansion of the nonspherical gravitational potential function.

  20. Preliminary study of the application of the Timation 3 satellite to earth physics

    NASA Technical Reports Server (NTRS)

    Carpenter, L. (Editor)

    1972-01-01

    The Timation 3 is a timing and navigation satellite originally planned for launch in December 1972 into a circular orbit at 98 deg inclination 14,000 km altitude with gravity gradient stabilization. An error analysis indicates a satellite position uncertainty of about one meter, 80 percent of which is attributable to the assumed gravity model errors. The remaining uncertainties have a period equal to that of the satellites and can be filtered out yielding an effective uncertainty of about 10 cm in the study of phenomena having different periodicities. The accomplishment of these results depends on a careful consideration of solar radiation pressure taking account of the spacecraft reflecting properties and variations in the presentation area. Consideration is also given to the displacement of the laser reflectors from the center of mass of the spacecraft and to the dynamic coupling of any libration in attitude with the orbital motion. The results indicate that a good set of well distribution laser observations of Timation 3 could yield determinations of polar motion, sea floor spreading, solid earth tides, and earth rotation at the 10 cm level.

  1. Modeling the satellite particles in planetary exospheres : application to Titan, Earth and Mars

    NASA Astrophysics Data System (ADS)

    Beth, A.; Kotova, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Brandt, P. C.; Dialynas, K.; Krimigis, S. M.

    2012-04-01

    The planetary exospheres are poorly known in their outer parts, since neutral densities are low compared with the instruments detection capabilities. Exospheric models are thus often the main source of information at such high altitudes. We revisit here the importance of a specific exospheric population, i.e. satellite particles, which is usually neglected in the models. These particles are indeed produced through rare collisions in the exospheres, and may either be negligible or dominate the exospheres of all planets with dense atmospheres in our solar system, depending on the balance between their sources and losses. At Titan, such calculations suggest a negligible contribution of H2 satellite populations compared to H2 ballistic populations, in contradiction with conclusions inferred from energetic neutral atom images by the Cassini MIMI/INCA imager. The application to Earth predicts that H satellite particles are the dominant population in the exosphere above 4 Earth radii , with a total density in agreement with recent IBEX observations. We finally show the first results for O particles in the Martian environment.

  2. ULF wave observations in the topside ionosphere from the low-Earth orbit Swarm satellites

    NASA Astrophysics Data System (ADS)

    Balasis, Georgios; Daglis, Ioannis A.; Papadimitriou, Constantinos; Giannakis, Omiros

    2016-07-01

    The ongoing Swarm satellite mission provides an opportunity to a better knowledge of the near-Earth electromagnetic environment. Herein, we study the occurrence of ultra low frequency (ULF) wave events observed by the Swarm satellite mission for a period spanning twenty months after the constellation's final configuration. We present maps of the dependence of ULF wave power with magnetic latitude and magnetic local time (MLT) as well as geographic latitude and longitude from the three satellites at their different locations in the topside ionosphere. We derive daily and monthly variations of the Pc3 wave power (20-100 mHz) and show distributions for various wave properties of the detected events. Moreover, we include Swarm power maps of equatorial spread-F (ESF) signatures in the topside ionosphere revealing a global mirror fine structure along the magnetic equator for these instabilities. We also found an enhancement of ESF power in the region of South Atlantic Anomaly (SAA) in agreement with the recently discovered by Swarm enhancement of compressional Pc3 wave energy in SAA. By combining Swarm results with wave observations from magnetospheric missions and ground-based magnetometer arrays we offer a useful platform to monitor the wave evolution from the outer boundaries of Earth's magnetosphere through the topside ionosphere down to the surface.

  3. Iridium NEXT partnership for Earth observation: exploiting global satellite constellations for new remote sensing capabilities

    NASA Astrophysics Data System (ADS)

    Gupta, Om P.

    2008-08-01

    A unique opportunity exists to host up to 66 earth observation sensors on the Iridium NEXT LEO constellation in a manner that can revolutionize earth observation and weather predictions. A constellation approach to sensing, using the real-time communications backbone of Iridium, will enable unprecedented geospatial and temporal sampling for now-casting of weather on a global basis as well as global climate monitoring. The Iridium NEXT constellation, with 66 interconnected satellites in 6 near polar orbiting planes, provides a unique platform for hosting a variety of earth observation missions. The opportunity is proposed as a Public-Private Partnership (PPP) allowing for the sharing of infrastructure by government agencies. This has the potential to augment current and planned climate and weather observation programs in a very cost effective manner not achievable in any other way. Iridium, with the assistance of the Group on Earth Observations (GEO), NASA, NOAA, and ESA, has evaluated a number of sensing missions that would be a good fit to the Iridium NEXT constellation. These include GPS radio occultation sensors, earth radiation budget measurements, radio altimetry, tropospheric and stratospheric winds measurements including polar winds measurements, and atmospheric chemistry. Iridium NEXT launches start in 2013 and constellation operational life will extend beyond 2030. Detailed feasibility studies on specific missions are planned to begin later this year.

  4. A comparative study of spherical and flat-Earth geopotential modeling at satellite elevations

    NASA Technical Reports Server (NTRS)

    Parrott, M. H.; Hinze, W. J.; Braile, L. W.; Vonfrese, R. R. B.

    1985-01-01

    Flat-Earth modeling is a desirable alternative to the complex spherical-Earth modeling process. These methods were compared using 2 1/2 dimensional flat-earth and spherical modeling to compute gravity and scalar magnetic anomalies along profiles perpendicular to the strike of variably dimensioned rectangular prisms at altitudes of 150, 300, and 450 km. Comparison was achieved with percent error computations (spherical-flat/spherical) at critical anomaly points. At the peak gravity anomaly value, errors are less than + or - 5% for all prisms. At 1/2 and 1/10 of the peak, errors are generally less than 10% and 40% respectively, increasing to these values with longer and wider prisms at higher altitudes. For magnetics, the errors at critical anomaly points are less than -10% for all prisms, attaining these magnitudes with longer and wider prisms at higher altitudes. In general, in both gravity and magnetic modeling, errors increase greatly for prisms wider than 500 km, although gravity modeling is more sensitive than magnetic modeling to spherical-Earth effects. Preliminary modeling of both satellite gravity and magnetic anomalies using flat-Earth assumptions is justified considering the errors caused by uncertainties in isolating anomalies.

  5. Determination of global Earth outgoing radiation at high temporal resolution using a theoretical constellation of satellites

    NASA Astrophysics Data System (ADS)

    Gristey, Jake J.; Chiu, J. Christine; Gurney, Robert J.; Han, Shin-Chan; Morcrette, Cyril J.

    2017-01-01

    New, viable, and sustainable observation strategies from a constellation of satellites have attracted great attention across many scientific communities. Yet the potential for monitoring global Earth outgoing radiation using such a strategy has not been explored. To evaluate the potential of such a constellation concept and to investigate the configuration requirement for measuring radiation at a time resolution sufficient to resolve the diurnal cycle for weather and climate studies, we have developed a new recovery method and conducted a series of simulation experiments. Using idealized wide field-of-view broadband radiometers as an example, we find that a baseline constellation of 36 satellites can monitor global Earth outgoing radiation reliably to a spatial resolution of 1000 km at an hourly time scale. The error in recovered daily global mean irradiance is 0.16 W m-2 and -0.13 W m-2, and the estimated uncertainty in recovered hourly global mean irradiance from this day is 0.45 W m-2 and 0.15 W m-2, in the shortwave and longwave spectral regions, respectively. Sensitivity tests show that addressing instrument-related issues that lead to systematic measurement error remains of central importance to achieving similar accuracies in reality. The presented error statistics therefore likely represent the lower bounds of what could currently be achieved with the constellation approach, but this study demonstrates the promise of an unprecedented sampling capability for better observing the Earth's radiation budget.

  6. The Italian Space Agency Support in the Committee on Earth Observation Satellites (CEOS)

    NASA Astrophysics Data System (ADS)

    Pisani, Anna Rita; Virelli, Maria; Zoffoli, Simona; Coletta, Alessandro; Candela, Laura Giulia

    2016-08-01

    The Disaster Risk Reduction (DRR) is an important political, economical and societal objective to reduce severe losses and damages caused by natural phenomena or human activity.The Earth Observation (EO) satellites data have been recognised as a useful support for politicians, decision- makers and major stakeholders in all phases of the Disaster Risk Management (DRM).In this framework since 2013 the Committee on Earth Observation Satellites (CEOS) has established the Working Group on Disasters (WG Disasters) to coordinate space agencies efforts in projects focussed on the challenge of the DRR through the EO data exploitation.In order to achieve this purpose CEOS activated three thematic pilot projects (Volcano, Seismic and Flood) and the Recovery Observatory (RO) and supports the Geohazard Supersites and Natural Laboratories (GSNL) initiative of the Group on Earth Observations (GEO). The Italian Space Agency (ASI) participates in CEOS activities since 1986 supporting the GSNL since 2012 and the DRM pilot projects and the RO since the beginning, providing COSMO-SkyMed (CSK) data.In this work recent results achieved by some among the projects in the framework of the CEOS WG Disaster projects, also reported during the last Working Group on Disasters 5th meeting held in Bonn (March 8th-10th, 2016), will be presented, with a focus on the DRM Seismic and Volcano pilots projects (Lefkada earthquake and Cordon Caulle Volcano) and on some Supersites (Hawaii, Bardarbunga and Campi Flegrei).

  7. Earth-To-Satellite Microwave Beams: Innovative Approach To Space Power

    NASA Astrophysics Data System (ADS)

    Hoffert, M. I.; Miller, G.; Heilweil, B.; Ziegler, W.; Kadiramangalam, M.

    1988-05-01

    A new space power concept incorporating earth-to-satellite microwave power beams coupled to onboard regenerative electrochemical energy storage is proposed for energizing defensive satellite constellations. The system addresses housekeeping, orbital maneuvering and burst mode power requirements, and offers an attractive alternative to the nuclear and solar space power systems currently envisioned for this application. This energy-conversion system incorporates six steps: (1) generate primary DC power at surface stations along the satellite ground-track, (2) convert to microwave (RF) frequencies, (3) transmit in a narrow beam to spacecraft using phased-array antennas which track and lock-on to satellite receivers as they pass in range during a fraction of their orbit, (4) receive the energy and convert to DC in space using lightweight and inexpensive rectennas; (5) store the energy onboard as chemical energy by electrolysis of water to oxygen and hydrogen and (6) recover free energy onboard the spacecraft during the balance of the orbit continuously or on demand as pulsed power with a high power-density fuel cell. Component and overall systems considerations of this scheme are discussed in comparison with alternatives, outstanding research problems are defined and preliminary analyses are described. These include orbital mechanics and ground tracks of satellites, accessibility of orbiters to microwave beams, transmission efficiencies, electronic and mechanical designs of the transmitter and rectenna, regenerative fuel cell energy storage, power conditioning and thermal management. The development of readily space-deployable rectennae, their supporting structures, and high specific power solid oxide monolithic fuels cells are the main pacing technologies leading to a wholly non-nuclear space power system capable of supporting all defensive satellite power requirements.

  8. Using artificial neural network and satellite data to predict rice yield in Bangladesh

    NASA Astrophysics Data System (ADS)

    Akhand, Kawsar; Nizamuddin, Mohammad; Roytman, Leonid; Kogan, Felix; Goldberg, Mitch

    2015-09-01

    Rice production in Bangladesh is a crucial part of the national economy and providing about 70 percent of an average citizen's total calorie intake. The demand for rice is constantly rising as the new populations are added in every year in Bangladesh. Due to the increase in population, the cultivation land decreases. In addition, Bangladesh is faced with production constraints such as drought, flooding, salinity, lack of irrigation facilities and lack of modern technology. To maintain self sufficiency in rice, Bangladesh will have to continue to expand rice production by increasing yield at a rate that is at least equal to the population growth until the demand of rice has stabilized. Accurate rice yield prediction is one of the most important challenges in managing supply and demand of rice as well as decision making processes. Artificial Neural Network (ANN) is used to construct a model to predict Aus rice yield in Bangladesh. Advanced Very High Resolution Radiometer (AVHRR)-based remote sensing satellite data vegetation health (VH) indices (Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) are used as input variables and official statistics of Aus rice yield is used as target variable for ANN prediction model. The result obtained with ANN method is encouraging and the error of prediction is less than 10%. Therefore, prediction can play an important role in planning and storing of sufficient rice to face in any future uncertainty.

  9. Using remote sensing satellite data and artificial neural network for prediction of potato yield in Bangladesh

    NASA Astrophysics Data System (ADS)

    Akhand, Kawsar; Nizamuddin, Mohammad; Roytman, Leonid; Kogan, Felix

    2016-09-01

    Potato is one of the staple foods and cash crops in Bangladesh. It is widely cultivated in all of the districts and ranks second after rice in production. Bangladesh is the fourth largest potato producer in Asia and is among the world's top 15 potato producing countries. The weather condition for potato cultivation is favorable during the sowing, growing and harvesting period. It is a winter crop and is cultivated during the period of November to March. Bangladesh is mainly an agricultural based country with respect to agriculture's contribution to GDP, employment and consumption. Potato is a prominent crop in consideration of production, its internal demand and economic value. Bangladesh has a big economic activities related to potato cultivation and marketing, especially the economic relations among farmers, traders, stockers and cold storage owners. Potato yield prediction before harvest is an important issue for the Government and the stakeholders in managing and controlling the potato market. Advanced very high resolution radiometer (AVHRR) based satellite data product vegetation health indices VCI (vegetation condition index) and TCI (temperature condition index) are used as predictors for early prediction. Artificial neural network (ANN) is used to develop a prediction model. The simulated result from this model is encouraging and the error of prediction is less than 10%.

  10. Evolution of NASA's Near-Earth Tracking and Data Relay Satellite System (TDRSS)

    NASA Technical Reports Server (NTRS)

    Flaherty, Roger; Stocklin, Frank; Weinberg, Aaron

    2006-01-01

    NASA's Tracking and Data Relay Satellite System (TDRSS) is now in its 23rd year of operations and its spacecraft fleet includes three second-generation spacecraft launched since the year 2000; a figure illustrates the first generation TDRSS spacecraft. During this time frame the TDRSS has provided communications relay support to a broad range of missions, with emphasis on low-earth-orbiting (LEO) spacecraft that include unmanned science spacecraft (e.g., Hubble Space Telescope), and human spaceflight (Space Shuttle and Space Station). Furthermore, the TDRSS has consistently demonstrated its uniqueness and adaptability in several ways. First, its S- and K-band services, combined with its multi-band/steerable single-access (SA) antennas and ground-based configuration flexibility, have permitted the mission set to expand to unique users such as scientific balloons and launch vehicles. Second, the bent-pipe nature of the system has enabled the introduction of new/improved services via technology insertion and upgrades at each of the ground terminals; a specific example here is the Demand Access Service (DAS), which, for example, is currently providing science-alert support to NASA science missions Third, the bent-pipe nature of the system, combined with the flexible ground-terminal signal processing architecture has permitted the demonstration/vaIidation of new techniques/services/technologies via a real satellite channel; over the past 10+ years these have, for example, included demonstrations/evaluations of emerging modulation/coding techniques. Given NASA's emerging Exploration plans, with missions beginning later this decade and expanding for decades to come, NASA is currently planning the development of a seamless, NASA-wide architecture that must accommodate missions from near-earth to deep space. Near-earth elements include Ground-Network (GN) and Near-Earth Relay (NER) components and both must efficiently and seamlessly support missions that encompass: earth

  11. Near-Earth asteroid satellite spins under spin-orbit coupling

    SciTech Connect

    Naidu, Shantanu P.; Margot, Jean-Luc

    2015-02-01

    We develop a fourth-order numerical integrator to simulate the coupled spin and orbital motions of two rigid bodies having arbitrary mass distributions under the influence of their mutual gravitational potential. We simulate the dynamics of components in well-characterized binary and triple near-Earth asteroid systems and use surface of section plots to map the possible spin configurations of the satellites. For asynchronous satellites, the analysis reveals large regions of phase space where the spin state of the satellite is chaotic. For synchronous satellites, we show that libration amplitudes can reach detectable values even for moderately elongated shapes. The presence of chaotic regions in the phase space has important consequences for the evolution of binary asteroids. It may substantially increase spin synchronization timescales, explain the observed fraction of asychronous binaries, delay BYORP-type evolution, and extend the lifetime of binaries. The variations in spin rate due to large librations also affect the analysis and interpretation of light curve and radar observations.

  12. Opportunities investigating the thermosphere/ionosphere system by low Earth orbiting satellite missions (Invited)

    NASA Astrophysics Data System (ADS)

    Stolle, C.; Park, J.; Luhr, H.

    2013-12-01

    New opportunities for investigating the thermosphere/ionosphere interactions arise from in situ measurements on board low Earth orbiting satellites. Ten years of successful operation of the CHAMP satellite mission at a unique orbit altitude of about 400 km revealed many interesting features of the coupling between the thermosphere and ionosphere and the different atmospheric layers. Examples are the investigations of signatures of stratospheric warming events that are known to change significantly the dynamics of the equatorial ionosphere. It was shown that these modifications are due to an enhancement of lunar tidal effects, e.g. reflected in the thermospheric zonal wind, in the equatorial electroje or in the eastward electric field. Another topic concerns the energy deposit in the F-region though cooling of the thermal electron gas caused by elastic and inelastic processes (Schunk and Nagy, 2009). We find that a significant deposition is present during day at mid latitudes. At low latitudes the energy flux remain important until midnight. Observed heating rates depend on the satellite altitudes, but they are globally available from the CHAMP data. Further enhanced investigations are expected from ESA's three-satellite Swarm mission with a launch planned in 2014. The mission will provide observations of electron density, electron and ion temperature, ion drift and the electric field together with neutral density and winds. High-precision magnetic field observations will allow monitoring ionospheric currents.

  13. Methods to Improve the Maintenance of the Earth Catalog of Satellites During Severe Solar Storms

    NASA Technical Reports Server (NTRS)

    Wilkin, Paul G.; Tolson, Robert H.

    1998-01-01

    The objective of this thesis is to investigate methods to improve the ability to maintain the inventory of orbital elements of Earth satellites during periods of atmospheric disturbance brought on by severe solar activity. Existing techniques do not account for such atmospheric dynamics, resulting in tracking errors of several seconds in predicted crossing time. Two techniques are examined to reduce of these tracking errors. First, density predicted from various atmospheric models is fit to the orbital decay rate for a number of satellites. An orbital decay model is then developed that could be used to reduce tracking errors by accounting for atmospheric changes. The second approach utilizes a Kalman filter to estimate the orbital decay rate of a satellite after every observation. The new information is used to predict the next observation. Results from the first approach demonstrated the feasibility of building an orbital decay model based on predicted atmospheric density. Correlation of atmospheric density to orbital decay was as high as 0.88. However, it is clear that contemporary: atmospheric models need further improvement in modeling density perturbations polar region brought on by solar activity. The second approach resulted in a dramatic reduction in tracking errors for certain satellites during severe solar Storms. For example, in the limited cases studied, the reduction in tracking errors ranged from 79 to 25 percent.

  14. Satellite communications provisions on NASA Ames instrumented aircraft platforms for Earth science research/applications

    NASA Technical Reports Server (NTRS)

    Shameson, L.; Brass, J. A.; Hanratty, J. J.; Roberts, A. C.; Wegener, S. S.

    1995-01-01

    Earth science activities at NASA Ames are research in atmospheric and ecosystem science, development of remote sensing and in situ sampling instruments, and their integration into scientific research platform aircraft. The use of satellite communications can greatly extend the capability of these agency research platform aircraft. Current projects and plans involve satellite links on the Perseus UAV and the ER-2 via TDRSS and a proposed experiment on the NASA Advanced Communications Technology Satellite. Provisions for data links on the Perseus research platform, via TDRSS S-band multiple access service, have been developed and are being tested. Test flights at Dryden are planned to demonstrate successful end-to-end data transfer. A Unisys Corp. airborne satcom STARLink system is being integrated into an Ames ER-2 aircraft. This equipment will support multiple data rates up to 43 Mb/s each via the TDRS S Ku-band single access service. The first flight mission for this high-rate link is planned for August 1995. Ames and JPL have proposed an ACTS experiment to use real-time satellite communications to improve wildfire research campaigns. Researchers and fire management teams making use of instrumented aircraft platforms at a prescribed burn site will be able to communicate with experts at Ames, the U.S. Forest Service, and emergency response agencies.

  15. Modeling the satellite particles in planetary exospheres : application to Titan, Earth and Mars

    NASA Astrophysics Data System (ADS)

    Beth, A.; Garnier, P.; Toublanc, D.; Dandouras, I.; Kotova, A.; Brandt, P. C.; Dialynas, K.; Krimigis, S. M.

    2012-12-01

    The planetary exospheres are poorly known in their outer parts, since neutral densities are low compared with the instruments detection capabilities. Exospheric models are thus often the main source of information at such high altitudes. We revisit here the importance of a specific exospheric population, i.e. satellite particles, which is usually neglected in the models. These particles are indeed produced through rare collisions in the exospheres (elastic, charge exchange, etc …) at low altitudes and may either be negligible or dominate the exospheres of all planets with dense atmospheres in our solar system, depending on the balance between their sources and losses. At Titan, such calculations using the Boltzmann equation suggest a negligible contribution of H2 satellite populations compared to H2 ballistic populations by one or two orders of magnitude, in contradiction with conclusions inferred from energetic neutral atom images by the Cassini MIMI/INCA imager. The application to Earth predicts that H satellite particles, produced in their majority by elastic collisions with O atoms, are negligible by two orders of magnitude too, with a total density in good agreement with recent IBEX observations. We finally show the first results for cold H and cold O satellite particles in the Martian environment.

  16. Estimating Photosynthetically Available Radiation (PAR) at the Earth's surface from satellite observations

    NASA Technical Reports Server (NTRS)

    Frouin, Robert

    1993-01-01

    Current satellite algorithms to estimate photosynthetically available radiation (PAR) at the earth' s surface are reviewed. PAR is deduced either from an insolation estimate or obtained directly from top-of-atmosphere solar radiances. The characteristics of both approaches are contrasted and typical results are presented. The inaccuracies reported, about 10 percent and 6 percent on daily and monthly time scales, respectively, are useful to model oceanic and terrestrial primary productivity. At those time scales variability due to clouds in the ratio of PAR and insolation is reduced, making it possible to deduce PAR directly from insolation climatologies (satellite or other) that are currently available or being produced. Improvements, however, are needed in conditions of broken cloudiness and over ice/snow. If not addressed properly, calibration/validation issues may prevent quantitative use of the PAR estimates in studies of climatic change. The prospects are good for an accurate, long-term climatology of PAR over the globe.

  17. Earth Observatory Satellite system definition study. Report no. 2: Instrument constraints and interface specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The instruments to be flown on the Earth Observatory Satellite (EOS) system are defined. The instruments will be used to support the Land Resources Management (LRM) mission of the EOS. Program planning information and suggested acquisition activities for obtaining the instruments are presented. The subjects considered are as follows: (1) the performance and interface of the Thematic Mapper (TM) and the High Resolution Pointing Imager (HRPI), (2) procedure for interfacing the TM and HRPI with the EOS satellite, (3) a space vehicle integration plan suggesting the steps and sequence of events required to carry out the interface activities, and (4) suggested agreements between the contractors for providing timely and equitable solution of problems at minimum cost.

  18. New insights from satellite magnetic gradient observations into the determination of Earth's lithospheric field

    NASA Astrophysics Data System (ADS)

    Kotsiaros, S.; Olsen, N.; Finlay, C. C.

    2015-12-01

    Satellites provide a large stream of data with global coverage and are ideal for deriving global models of the Earth's magnetic field. However, the determination of smaller-scale lithospheric magnetic field features is problematic because the lithospheric signal is contaminated by much larger and highly time-dependent contributions from sources in the ionosphere and magnetosphere. New possibilities open with the three Swarm satellites which provide high quality, simultaneous, measurements from different locations. In addition, North-South and East-West magnetic field gradients can be approximated by employing along-track and across-track field differences which act as high-pass filters of the data and data kernel. We present improvements of conventional lithospheric field modeling approaches to better determine the small-scale lithospheric field by incorporating gradient information.

  19. Satellite soil moisture for advancing our understanding of earth system processes and climate change

    NASA Astrophysics Data System (ADS)

    Dorigo, Wouter; de Jeu, Richard

    2016-06-01

    Soil moisture products obtained from active and passive microwave satellites have reached maturity during the last decade (De Jeu and Dorigo, 2016): On the one hand, research algorithms that were initially applied to sensors designed for other purposes, e.g., for measuring wind speed (e.g. the Advanced Scatterometer (ASCAT)), sea ice, or atmospheric parameters (e.g. the TRMM Microwave Imager (TMI) and the Advanced Microwave Scanning Radiometer - Earth Observing System AMSR-E), have developed into fully operational products. On the other hand, dedicated soil moisture satellite missions were designed and launched by ESA (the Soil Moisture Ocean Salinity (SMOS) mission) and NASA (the Soil Moisture Active Passive (SMAP) mission).

  20. The first Earth Resources Technology Satellite - Nearly two years of operation

    NASA Technical Reports Server (NTRS)

    Nordberg, W.

    1974-01-01

    A brief status report is given of the ERTS-1 satellite system as of June, 1974, and some applications of the ERTS-1 images are discussed. The multispectral images make it possible to identify or measure the quality and composition of water, the potential water content of snow, the moisture and possible composition of soils, the types and state of vegetation cover, and factors relating to stresses on the environment. The orthographic view of the earth provided by the satellite makes it possible to rapidly produce thematic maps, on a scale of 1:250,000, of most areas of the world. The regular, repetitive coverage provided by ERTS-1 every 18 days is important in areas such as water-supply and flood-damage studies. The use of ERTS-1 imagery for land-use planning, wetlands surveying, assessing marine resources, and observing processes such as desertification in the African Sahel is discussed.

  1. Constraints on Energy Dissipation in the Earth's Body Tide From Satellite Tracking and Altimetry

    NASA Technical Reports Server (NTRS)

    Ray, Richard D.; Eanes, Richard J.; Lemoine, Frank G.

    1992-01-01

    The phase lag by which the earth's body tide follows the tidal potential is estimated for the principal lunar semidiurnal tide M(sub 2). The estimate results from combining recent tidal solutions from satellite tracking data and from Topex/Poseidon satellite altimeter data. Each data type is sensitive to the body-tide lag: gravitationally for the tracking data, geometrically for the altimetry. Allowance is made for the lunar atmospheric tide. For the tidal potential Love number kappa(sub 2) we obtain a lag epsilon of 0.20 deg +/- 0.05 deg, implying an effective body-tide Q of 280 and body-tide energy dissipation of 110 +/- 25 gigawatts.

  2. Improving the Transition of Earth Satellite Observations from Research to Operations

    NASA Technical Reports Server (NTRS)

    Goodman, Steven J.; Lapenta, William M.; Jedlovec, Gary J.

    2004-01-01

    There are significant gaps between the observations, models, and decision support tools that make use of new data. These challenges include: 1) Decreasing the time to incorporate new satellite data into operational forecast assimilation systems, 2) Blending in-situ and satellite observing systems to produce the most accurate and comprehensive data products and assessments, 3) Accelerating the transition from research to applications through national test beds, field campaigns, and pilot demonstrations, and 4) Developing the partnerships and organizational structures to effectively transition new technology into operations. At the Short-term Prediction Research and Transition (SPORT) Center in Huntsville, Alabama, a NASA-NOAA-University collaboration has been developed to accelerate the infusion of NASA Earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The SPoRT Center research focus is to improve forecasts through new observation capability and the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues such as convective initiation and 24-hr quantitative precipitation forecasting. The near real-time availability of high-resolution experimental products of the atmosphere, land, and ocean from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Infrared Spectroradiometer (AIRS), and lightning mapping systems provide an opportunity for science and algorithm risk reduction, and for application assessment prior to planned observations from the next generation of operational low Earth orbiting and geostationary Earth orbiting satellites. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future. The SPoRT Web page is at (http://www.ghcc.msfc.nasa.gov/sport).

  3. A vector method for synthesis of orbits and the structure of satellite constellations for multiswath periodic coverage of the Earth

    NASA Astrophysics Data System (ADS)

    Saulskiy, V. K.

    2016-07-01

    Single satellites and multisatellite constellations for the periodic coverage of the Earth are considered. The main feature is the use of several cameras with different swath widths. A vector method is proposed which makes it possible to find orbits minimizing the periodicities of coverage of a given area of Earth uniformly for all swaths. Their number is not limited, but the relative dimensions should satisfy the Fibonacci series or some new numerical sequences. The results apply to constellations of any number of satellites. Formulas were derived for calculating their structure, i.e., relative position in the constellation. Examples of orbits and the structure of constellations for the Earth's multiswath coverage are presented.

  4. Modeling the satellite particles in planetary exospheres: application to Earth, Titan and Mars.

    NASA Astrophysics Data System (ADS)

    Beth, Arnaud; Garnier, Philippe; Toublanc, Dominique; Dandouras, Iannis; Mazelle, Christian; Kotova, Anna

    2013-04-01

    The planetary exospheres are poorly known in their outer parts, since neutral densities are low compared with the instruments detection capabilities. Exospheric models are thus often the main source of information at such high altitudes. We revisit here the importance of a specific exospheric population, i.e. satellite particles, which is usually neglected in the models. These particles are indeed produced through rare collisions in the exospheres, and may either be negligible or dominate the exospheres of all planets with dense atmospheres in our solar system, depending on the balance between their sources and losses. Richter (1979) were the first to propose, beyond the Chamberlain's (Chamberlain (1987)) rough approximation, a rigorous approach for these particles by using the Boltzmann equation in the Earth exosphere between 500 km and 3000 km altitude. They pointed out their negligible presence at low altitudes without doing this calculation at higher altitudes. We attempt here to apply the same formalism for other planetary exospheres: Mars and Titan thanks to improvements in the computing power and the collected planetary data. In particular, we determine the contribution of satellite populations to the densities of light elements (molecular hydrogen on Titan, atomic hydrogen on Earth and Mars) and evaluate the possible error on the total density if the satellite particles are neglected. The satellite populations may represent up to 50 % of the ballistic and escaping populations (those considered in the collisionless models) in the case of H on Mars, suggesting that the collisionless models of exospheric densities may be inaccurate at high altitudes for some conditions.

  5. Earth Observatory Satellite system definition study. Report no. 7: EOS system definition report

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The design concept and operational aspects of the Earth Observatory Satellite (EOS) are presented. A table of the planned EOS missions is included to show the purpose of the mission, the instruments involved, and the launch date. The subjects considered in the analysis of the EOS development are: (1) system requirements, (2) design/cost trade methodology, (3) observatory design alternatives, (4) the data management system, (5) the design evaluation and preferred approach, (6) program cost compilation, (7) follow-on mission accommodation, and (8) space shuttle interfaces and utilization. Illustrations and block diagrams of the spacecraft configurations are provided.

  6. A study of Minnesota forests and lakes using data from earth resources technology satellites

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This project is to foster and develop new applications of remote sensing under an interdisciplinary effort. Seven reports make up the specific projects presently being conducted throughout the State of Minnesota in cooperation with several agencies and municipalities. These are included under the general headings of: (1) applications of aerial photography and ERTS-1 data to agricultural, forest, and water resources management; (2) classification and dynamics of water and wetland resources of Minnesota; (3) studies of Lake Superior Bay; and (4) feasibility of detecting major air pollutants by earth-oriented satellite-borne sensors.

  7. Earth Observatory Satellite system definition study. Report 2: Instrument constraints and interfaces

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The instrument constraints and interface specifications for the Earth Observatory Satellite (EOS) are discussed. The Land Use Classification Mission using a 7 band Thematic Mapper and a 4 band High Resolution Pointable Imager is stressed. The mission and performance of the instruments were reviewed and expanded to reflect the instrument as a part of the total remote sensing system. A preliminary EOS interface handbook is provided to describe the mission and system, to specify the spacecraft interfaces to potential instrument contractors, and to describe the instrument interface data required by the system integration contractor.

  8. Earth Radiation Budget Satellite extraterrestrial solar constant measurements - 1986-1987 increasing trend

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Barkstrom, Bruce R.; Harrison, Edwin F.; Gibson, Michael A.; Natarajan, Sudha M.; Edmonds, William L.; Mecherikunnel, Ann T.; Kyle, H. Lee

    1988-01-01

    From June 1986 through Nov 1987, the Earth Radiation Budget Satellite (ERBS) pyrheliometric measurements indicated that the solar constant was increasing approximately +0.02 percent per year. Earlier ERBS measurements indicated that the solar constant was declining approximately -0.03 percent per year during the 1984 through mid-1986 period. Since mid-1986 represents the beginning of solar cycle 22, it is believed that the reversal in the long-term solar constant trend may be linked to increased solar activity associated with the beginning of the 11-year sunspot cycle. The typical value of the solar constant was found to be 1365 Wm-2.

  9. Orbit/launch vehicle tradeoff studies. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An evaluation of the Earth Observatory Satellite (EOS) design, performance, and cost factors which affect the choices of an orbit and a launch vehicle is presented. Primary emphasis is given to low altitude (300 to 900 nautical miles) land resources management applications for which payload design factors are defined. The subjects considered are: (1) a mission model, (2) orbit analysis and characterization, (3) characteristics and capabilities of candidate conventional launch vehicles, and space shuttle support. Recommendations are submitted for the EOS-A mission, the Single Multispectral Scanner payload, the Single Multispectral Scanner plus Thematic Mapper payload, the Dual Multispectral Scanner payload, and the Dual Multispectral Scanner plus Thematic Mapper payload.

  10. Test of general relativity and measurement of the lense-thirring effect with two earth satellites

    PubMed

    Ciufolini; Pavlis; Chieppa; Fernandes-Vieira; Perez-Mercader

    1998-03-27

    The Lense-Thirring effect, a tiny perturbation of the orbit of a particle caused by the spin of the attracting body, was accurately measured with the use of the data of two laser-ranged satellites, LAGEOS and LAGEOS II, and the Earth gravitational model EGM-96. The parameter &mgr;, which measures the strength of the Lense-Thirring effect, was found to be 1.1 +/- 0.2; general relativity predicts &mgr; identical with 1. This result represents an accurate test and measurement of one of the fundamental predictions of general relativity, that the spin of a body changes the geometry of the universe by generating space-time curvature.

  11. Eigensensitivity in integrated design. [of earth-pointing satellite's control system

    NASA Technical Reports Server (NTRS)

    Kenny, Sean P.; Hou, Gene J.; Belvin, W. K.

    1990-01-01

    An application of eigensensitivity analysis to the control-structure integrated design process is presented with an emphasis placed on computational efficiency improvement of the overall design optimization process. The computational efficiency of eigenvalue/vector sensitivity analysis is demonstrated using the Earth Pointing Satellite in the context of a control-structure integrated design program. Results for a 2 percent design variable perturbation with and without the effects of the actuator mass show a 42 and 52 percent reduction in CPU time, respectively.

  12. Human factors analysis of workstation design: Earth Radiation Budget Satellite Mission Operations Room

    NASA Technical Reports Server (NTRS)

    Stewart, L. J.; Murphy, E. D.; Mitchell, C. M.

    1982-01-01

    A human factors analysis addressed three related yet distinct issues within the area of workstation design for the Earth Radiation Budget Satellite (ERBS) mission operation room (MOR). The first issue, physical layout of the MOR, received the most intensive effort. It involved the positioning of clusters of equipment within the physical dimensions of the ERBS MOR. The second issue for analysis was comprised of several environmental concerns, such as lighting, furniture, and heating and ventilation systems. The third issue was component arrangement, involving the physical arrangement of individual components within clusters of consoles, e.g., a communications panel.

  13. Exploring NASA Earth Science Satellite Data in the K-12 Classroom Using MY NASA DATA

    NASA Astrophysics Data System (ADS)

    Phelps, C. S.; Chambers, L. H.; Diones, D. D.; Moore, S. W.; Oots, P. C.

    2007-12-01

    Mentoring and inquirY using NASA Data on Atmospheric and earth science for Teachers and Amateurs (MY NASA DATA) is an Internet-based project aimed to bring real NASA Earth system satellite data into the K-12 science classroom. MY NASA DATA consists of a Web site that collects lesson plans, science project ideas, and specially developed documentation to help the target audience more easily use NASA's vast collection of data about the Earth system. The core engine of MY NASA DATA is the Live Access Server (LAS) that provides access to over 128 satellite data parameters for student inquiry. The LAS allows students to make custom geo- referenced color plots, line graphs and data files for spreadsheets for any given parameter, time and location of choice. Students may also actively compare parameters and generate difference or overlay plots to explore real issues and topics in Earth science. The MY NASA DATA Web site already contains over 50 user-contributed lesson plans and science projects that introduce teachers and students to using the LAS interactive analysis tool, and about twenty more contributions will be posted by mid-2008. Each lesson plan is linked to national and state Standards of Learning (SOL) for easy implementation into the science curriculum and includes learning outcomes, prerequisites, and other key pedagogical elements. In-depth unit plans and science fair project ideas are also collected to engage students in longer-term research and interpretation of the NASA satellite data parameters. Several of the projects encourage students to collect local scientific data over a period of time for comparison with the satellite data. Each lesson or project provides the age-appropriate scaffolding that allows students to make new discoveries by exploring real data while teaching basic scientific principals and methods. The MY NASA DATA project also utilizes new developments in media and technology to provide more options for involving users remotely. Digital

  14. ICESat-2: the next generation satellite for altimetric measurements of the Earth's surface

    NASA Astrophysics Data System (ADS)

    McLennan, Douglas; Leon, John; Markus, Thorsten; Neumann, Thomas; Busch, James; Henegar-Leon, Joy; Flanagan, Mark; Richardson, Cathy; Martino, Anthony; Satrom, John

    2014-10-01

    Understanding the causes and magnitude of change in the cryosphere remains a priority for earth science research. Over the past decade, NASA earth observing satellites have documented a decrease in both the extent and thickness of Arctic sea ice, and ongoing loss of grounded ice from the Greenland and Antarctic ice sheets. Understanding the pace and mechanisms of these changes requires long-term observations of ice sheets, sea ice thickness and sea ice extent. In response to this need, NASA's Goddard Space Flight Center (GSFC) is developing the ICESat-2 mission, a nextgeneration laser altimeter designed to measure changes in ice sheet elevation, sea ice thickness, and vegetation canopy height. Scheduled for launch in late 2017 with a three year mission life, ICESat-2 will use a photon-counting micropulse laser altimeter, the advanced topographic laser altimeter system (ATLAS) instrument to collect these key data.

  15. Earth radiation budget measurements from satellites and their interpretation for climate modeling and studies

    NASA Technical Reports Server (NTRS)

    Vonderhaar, T. H.; Stephens, G. L.; Campbell, G. G.

    1980-01-01

    The annual and seasonal averaged Earth atmosphere radiation budgets derived from the most complete set of satellite observations available are presented. The budgets were derived from a composite of 48 monthly mean radiation budget maps. Annually and seasonally averaged radiation budgets are presented as global averages and zonal averages. The geographic distribution of the various radiation budget quantities is described. The annual cycle of the radiation budget was analyzed and the annual variability of net flux was shown to be largely dominated by the regular semi and annual cycles forced by external Earth-Sun geometry variations. Radiative transfer calculations were compared to the observed budget quantities and surface budgets were additionally computed with particular emphasis on discrepancies that exist between the present computations and previous surface budget estimates.

  16. Mesoscale mapping of available solar energy at the earth's surface by use of satellites

    NASA Technical Reports Server (NTRS)

    Hiser, H. W.; Senn, H. V.

    1980-01-01

    A method is presented for use of cloud images in the visual spectrum from the SMS/GOES geostationary satellites to determine the hourly distribution of sunshine on the mesoscale. Cloud coverage and density as a function of time of day and season are evaluated through the use of digital data processing techniques. Seasonal geographic distributions of cloud cover/sunshine are converted to joules of solar radiation received at the earth's surface through relationships developed from long-term measurements of these two parameters at six widely distributed stations. The technique can be used to generate maps showing the geographic distribution of total solar radiation on the mesoscale which is received at the earth's surface.

  17. A GSFC alternative to the SLR MERIT constants. [LAGEOS satellite earth orientation monitoring

    NASA Technical Reports Server (NTRS)

    Christodoulidis, Demosthenes C.; Smith, David E.; Klosko, Steven M.; Torrence, Mark H.; Dunn, Peter J.

    1986-01-01

    The use of the Lageos satellite to monitor the earth's orientation is examined. The derivations of long wavelength ocean tidal parameters, a geocentric gravitational constant of 398,600.436 cu km/ sq sec + or - 0.0001 cu km/sq sec, and Love numbers using Lageos laser ranging data are described. The uncertainties of the geopotential model, GEM-L2 of Lerch et al. (1982), are discussed. The calculation of polar motion using the Lageos constants is considered. The Lageos constants are tested by applying them to independent laser ranging data. It is determined that the new constants improve the rms of fit to independent Lageos data and improve the earth orientation parameters compared to VLBI data obtained during the IRIS project.

  18. Earth Observatory Satellite system definition study. Report 7: EOS system definition report

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The Earth Observatory Satellite (EOS) study is summarized to show the modular design of a general purpose spacecraft, a mission peculiar segment which performs the EOS-A mission, an Operations Control Center, a Data Processing Facility, and a design for Low Cost Readout Stations. The study verified the practicality and feasibility of the modularized spacecraft with the capability of supporting many missions in the Earth Observation spectrum. The various subjects considered in the summary are: (1) orbit/launch vehicle tradeoff studies and recommendations, (2) instrument constraints and interfaces, (3) design/cost tradeoff and recommendations, (4) low cost management approach and recommendations, (5) baseline system description and specifications, and (6) space shuttle utilization and interfaces.

  19. Selection of a model of Earth's albedo radiation, practical calculation of its effect on the trajectory of a satellite

    NASA Technical Reports Server (NTRS)

    Walch, J. J.

    1985-01-01

    Theoretical models of Earth's albedo radiation was proposed. By comparing disturbing accelerations computed from a model to those measured in flight with the CACTUS Accelerometer, modified according to the results. Computation of the satellite orbit perturbations from a model is very long because for each position of this satellite the fluxes coming from each elementary surface of the terrestrial portion visible from the satellite must be summed. The speed of computation is increased ten times without significant loss of accuracy thanks to a stocking of some intermediate results. Now it is possible to confront the orbit perturbations computed from the selected model with the measurements of these perturbations found with satellite as LAGEOS.

  20. Sentinel Convoy: Synergetic Earth Observation with Satellites Flying in Formation with European Operational Missions

    NASA Astrophysics Data System (ADS)

    Regan, Amanda; Silvestrin, Pierluigi; Fernandez, Diego

    2016-08-01

    The successful launch of Sentinel-1A, Sentinel-1B, Sentinel-2A and Sentinel-3A signify the beginning of the dedicated space segment for the Copernicus Programme, which is the result of the partnership between the European Commission (EC) and the European Space Agency (ESA). These Sentinels are the first of a long-term operational series of Earth Observation (EO) satellites to be launched by Europe that will complement the already well-established series of meteorological missions.For the first time, these missions will provide a continuous and long term European capability for systematic observations of the Earth surface, its oceans and atmosphere to unprecedented accuracies, resolutions, and temporal coverage. If additional cost- effective missions could be flown together with these operational missions (including operational meteorological satellite series such as MetOp (Second Generation - SG) then the possibilities for meeting new Earth science and application objectives could be far- reaching e.g. fulfilling observational gaps, synergistic measurements of Earth system processes, etc. To explore this potential, the ESA initiated three exploratory paper studies (known as the EO-Convoy studies). The aim of these studies is two fold: Firstly, to identify scientific and operational objectives and needs that would benefit from additional in-orbit support. Secondly, to identify and develop a number of cost- effective mission concepts that would meet these objectives and needs. Each EO Convoy study is dedicated to a specific theme, namely: Study 1 - Ocean and Ice Applications, Study 2 - Land Applications and Study 3 - Atmospheric Applications.This paper will present the results of the EO-Convoy studies including an overview of the user needs and derived convoy concept descriptions. This paper shall focus on the resulting science benefits. Example convoy concepts to be presented include a passive C-band SAR flying with Sentinel-1 and possible free flying thermal

  1. USGS Earth Explorer Client for Co-Discovery of Aerial and Satellite Data

    NASA Astrophysics Data System (ADS)

    Longhenry, R.; Sohre, T.; McKinney, R.; Mentele, T.

    2011-12-01

    The United States Geological Survey (USGS) Earth Resources Observation Science (EROS) Center is home to one of the largest civilian collections of images of the Earth's surface. These images are collected from recent satellite platforms such as the Landsat, Terra, Aqua and Earth Observer-1, historical airborne systems such as digital cameras and side-looking radar, and digitized historical aerial photography dating to the 1930's. The aircraft scanners include instruments such as the Advanced Solid State Array Spectrometer (ASAS). Also archived at EROS are specialized collections of aerial images, such as high-resolution orthoimagery, extensive collections over Antarctica, and historical airborne campaigns such as the National Aerial Photography Program (NAPP) and the National High Altitude Photography (NHAP) collections. These collections, as well as digital map data, declassified historical space-based photography, and variety of collections such as the Global Land Survey 2000 (GLS2000) and the Shuttle Radar Topography Mission (SRTM) are accessible through the USGS Earth Explorer (EE) client. EE allows for the visual discovery and browse of diverse datasets simultaneously, permitting the co-discovery and selection refinement of both satellite and aircraft imagery. The client, in use for many years was redesigned in 2010 to support requirements for next generation Landsat Data Continuity Mission (LDCM) data access and distribution. The redesigned EE is now supported by standards-based, open source infrastructure. EE gives users the capability to search 189 datasets through one interface, including over 8.4 million frames of aerial imagery. Since April 2011, NASA datasets archived at the Land Processes Distributed Active Archive Center (LP DAAC) including the MODIS land data products and ASTER Level-1B data products over the U.S. and Territories were made available via the EE client enabling users to co-discover aerial data archived at the USGS EROS along with USGS

  2. 75 FR 7975 - Procedures to Govern the Use of Satellite Earth Stations on Board Vessels in the 5925-6425 MHz...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... COMMISSION 47 CFR Part 25 Procedures to Govern the Use of Satellite Earth Stations on Board Vessels in the... Satellite Earth Stations on Board Vessels in the 5925-6425 MHz/3700-4200 MHz Bands and 14.0-14.5 GHz/11.7-12.... Expiration Date: December 31, 2012. Title: Earth Stations on Board Vessels (ESV). Form No.: Not...

  3. Testing the gravitational interaction in the field of the Earth via satellite laser ranging and the Laser Ranged Satellites Experiment (LARASE)

    NASA Astrophysics Data System (ADS)

    Lucchesi, D. M.; Anselmo, L.; Bassan, M.; Pardini, C.; Peron, R.; Pucacco, G.; Visco, M.

    2015-08-01

    In this work, the Laser Ranged Satellites Experiment (LARASE) is presented. This is a research program that aims to perform new refined tests and measurements of gravitation in the field of the Earth in the weak field and slow motion (WFSM) limit of general relativity (GR). For this objective we use the free available data relative to geodetic passive satellite lasers tracked from a network of ground stations by means of the satellite laser ranging (SLR) technique. After a brief introduction to GR and its WFSM limit, which aims to contextualize the physical background of the tests and measurements that LARASE will carry out, we focus on the current limits of validation of GR and on current constraints on the alternative theories of gravity that have been obtained with the precise SLR measurements of the two LAGEOS satellites performed so far. Afterward, we present the scientific goals of LARASE in terms of upcoming measurements and tests of relativistic physics. Finally, we introduce our activities and we give a number of new results regarding the improvements to the modelling of both gravitational and non-gravitational perturbations to the orbit of the satellites. These activities are a needed prerequisite to improve the forthcoming new measurements of gravitation. An innovation with respect to the past is the specialization of the models to the LARES satellite, especially for what concerns the modelling of its spin evolution, the neutral drag perturbation and the impact of Earth's solid tides on the satellite orbit.

  4. The Artificial Satellites' Observation Using the Complex of Telescopes of RI "MAO"

    NASA Astrophysics Data System (ADS)

    Sybiryakova, Ye. S.; Shulga, O. V.; Vovk, V. S.; Kaliuzny, M. P.; Bushuev, F. I.; Kulichenko, M. O.; Haloley, M. I.; Chernozub, V. M.

    2017-02-01

    Special methods, means and software for cosmic objects' observation and processing of obtained results were developed. Combined method, which consists in separated accumulation of images of reference stars and artificial objects, is the main method used in observations of artificial cosmic objects. It is used for observations of artificial objects at all types of orbits.

  5. Inferring anthropogenic trends from satellite data for water-sustainability of US cities near artificial reservoirs

    NASA Astrophysics Data System (ADS)

    Yigzaw, Wondmagegn; Hossain, Faisal

    2015-10-01

    Anthropogenic activities affect the water cycle and water supply at global and regional spatial scales, and approaches to water management must consider anthropogenic inputs. One of the major inputs in local-to-regional availability of water and the water cycle is land use land cover change as a result of urbanization, artificial reservoirs, and irrigation activity. To understand evolving trends in local hydrologic cycle for water sustainability of growing cities, this study employed a multi-factorial approach involving population trends, water use (and demand), streamflow, and various satellite-derived water-relevant variables. These variables are daily precipitation (from Tropical Rainfall Measuring Mission-TRMM, 3B42.V7), Normalized Difference Vegetation Index (NDVI) (from Moderate Resolution Imaging Spectroradiometer-MODIS-MOD13A1), land surface temperature (LST) (from MODIS-MOD11A2), and land cover (MODIS-MCD12Q1). Long term trends in such data were used to understand temporal and spatial trends in impounded watersheds hosting a large and growing city. The cities studied for water sustainability were Atlanta, Georgia and Buford dam; Columbia, South Carolina and Saluda dam; Columbus, Ohio and Alum Creek dam; Montgomery, Alabama and Jordan dam; Tulsa, Oklahoma and Keystone dam; and Tuscaloosa, Alabama and Tuscaloosa dam. Our study reveals that daily mean stream flow has been decreasing in all but one (Tulsa) of the areas selected. Satellite data trends between 2000 and 2012 showed a steady decrease in precipitation and NDVI, while LST has gradually increased. We attribute the NDVI (i.e., gradual decrease in vegetation cover) to LST rather than precipitation trends. The results of this research suggest that future temperature projections from climate models can be used in understanding vegetation activity and water availability over the study areas. Cities with larger upstream watershed area are potentially more sustainable and resilient (than those with small

  6. Inferring Anthropogenic Trends from Satellite Data for Water-sustainability of US Cities Near Artificial Reservoirs

    NASA Astrophysics Data System (ADS)

    Yigzaw, W. Y.; Hossain, F.

    2015-12-01

    Impact of anthropogenic activities on water cycle and water supply has different effects at global and regional spatial scales, ensuing the need for a design and water management approach that considers anthropogenic inputs. One of the major inputs in local-to-regional availability of water and the water cycle are land use land cover change as a result of urbanization, artificial reservoirs and irrigation activity. This study employed a multi-factorial approach involving population trends, water use (and demand), streamflow; and various satellite derived water-relevant variables. These variables are: daily precipitation (from TRMM, 3B42.V7), Normalized Difference Vegetation Index-NDVI (from MODIS-MOD13A1), land surface temperature-LST (from MODIS-MOD11A2), and land cover (MODIS-MCD12Q1). Long terms exhibited by such data were used to understand temporal and spatial trends in impounded watersheds hosting a large and growing city in its proximity. The selected cities are: City of Atlanta-Georgia and Buford dam; Columbia-South Carolina and Saluda dam; Columbus-Ohio and Alum Creek dam; Montgomery-Alabama and Jordan dam; Tulsa-Oklahoma and Keystone dam; Tuscaloosa-Alabama and Tuscaloosa dam were selected. our study reveals that daily mean stream flow has been decreasing in all but one (Tulsa) of the areas selected. Satellite data trends between 2000 and 2012 showed a steady decrease in precipitation and NDVI; while LST has gradually increased. We attribute the NDVI (i.e., gradual decrease in vegetation cover) to LST rather than precipitation trends. The results of this research suggested that future temperature projection from climate models can be used in understanding vegetation activity and water availability over the study areas. Cities with larger upstream watershed area are potentially more sustainable and resilient (than those with small watersheds) as a result of spatial variability of water resources' response to climate change. Inter-basin water resources

  7. Satellite and earth science data management activities at the U.S. geological survey's EROS data center

    USGS Publications Warehouse

    Carneggie, David M.; Metz, Gary G.; Draeger, William C.; Thompson, Ralph J.

    1991-01-01

    The U.S. Geological Survey's Earth Resources Observation Systems (EROS) Data Center, the national archive for Landsat data, has 20 years of experience in acquiring, archiving, processing, and distributing Landsat and earth science data. The Center is expanding its satellite and earth science data management activities to support the U.S. Global Change Research Program and the National Aeronautics and Space Administration (NASA) Earth Observing System Program. The Center's current and future data management activities focus on land data and include: satellite and earth science data set acquisition, development and archiving; data set preservation, maintenance and conversion to more durable and accessible archive medium; development of an advanced Land Data Information System; development of enhanced data packaging and distribution mechanisms; and data processing, reprocessing, and product generation systems.

  8. Earth Radiation Imbalance from a Constellation of 66 Iridium Satellites: Technological Aspects

    NASA Technical Reports Server (NTRS)

    Wiscombe, W.; Chiu, C. J-Y.

    2012-01-01

    Iridium Communications Inc. is launching a new generation of polar orbiting communication satellites in 2015-2017. Iridium will provide a hosted payload bay on each of the 66 satellites (plus 6 in-space spares). This offers the potential for a paradigm shift in the way we measure Earth radiation imbalance from space, as well as massive cost savings. Because the constellation provides 24/7 global coverage, there is no need to account for diurnal cycle via extrapolations from uncalibrated narrowband geostationary imagers. And the spares can be rolled over to view the Sun and deep space, then transfer their calibration to the other members of the constellation during the frequent cross-overs. In part using simulations of the constellation viewing realistic Earth scenes, this presentation will address the technological aspects of such a constellation: (1) the calibration strategy; (2) the highly-accurate and stable radiometers for measuring outgoing flux; and (3) the GRACE-inspired algorithms for representing the outgoing flux field in spherical harmonics and thus achieving rv500-km spatial resolution and two-hour temporal resolution.

  9. Time-variable Earth's albedo model characteristics and applications to satellite sampling errors

    NASA Technical Reports Server (NTRS)

    Bartman, F. L.

    1981-01-01

    Characteristics of the time variable Earth albedo model are described. With the cloud cover multiplying factor adjusted to produce a global annual average albedo of 30.3, the global annual average cloud cover is 45.5 percent. Global annual average sunlit cloud cover is 48.5 percent; nighttime cloud cover is 42.7 percent. Month-to-month global average albedo is almost sinusoidal with maxima in June and December and minima in April and October. Month-to-month variation of sunlit cloud cover is similar, but not in all details. The diurnal variation of global albedo is greatest from November to March; the corresponding variation of sunlit cloud cover is greatest from May to October. Annual average zonal albedos and monthly average zonal albedos are in good agreement with satellite-measured values, with notable differences in the polar regions in some months and at 15 S. The albedo of some 10 deg by 10 deg. areas of the Earth versus zenith angle are described. Satellite albedo measurement sampling effects are described in local time and in Greenwich mean time.

  10. An assessment of models which use satellite data to estimate solar irradiance at the earth's surface

    NASA Astrophysics Data System (ADS)

    Raphael, C.; Hay, J. E.

    1984-05-01

    The performances of three models which use satellite data to estimate solar irradiance at the earth's surface are assessed using measured radiation data from a midlatitude location. Assessment of the models is made possible through the accurate earth location of the satellite imagery (to within + or - 2 pixels). Evaluations of the models for a variety of conditions reveal the need for revised coefficients for the Hay and Hanson (1978) model and Tarpley (1979) model and demonstrate the superior performance of the pysically-based Gautier et al. (1980) model on an hourly basis for partly cloudy and overcast conditions. However, compared to the clear-sky case all three models give poor results under partly cloudy and overcast conditions. An increase in the averaging period leads to marked decreases in the rms errors observed for the three models under all conditions, with the greatest improvement occuring for the Hay and Hanson model. Suggestions for improvements include a more accurate and explicit treatment of cloud absorption in all three models and the inclusion of the effects of aerosols under clear skies and the accurate and objective specification of a cloud threshold separating clear from partly cloudy and partly cloudy from overcast conditions in the Gautier et al. and Tarpley models.

  11. 0°C isotherm height distribution for Earth-space communication satellite links in Nigeria

    NASA Astrophysics Data System (ADS)

    Ojo, J. S.; Falodun, S. E.; Odiba, O.

    2014-06-01

    For an optimum performance of Earth-space satellite communication links, a number of meteorological parameters are needed to be considered along the Earth-space path for specific locations and the height of the 0°C isotherm (freezing level height) is among such parameters. Information regarding this parameter is always based on the recommendation of ITU-RP-839 in the form of contour maps. Since the meteorological parameters are location dependent, there is a need for the establishment of these parameters for specific locations. In addition, ITU-R model uses an yearly averaged constant rain height for the attenuation estimation, which may not be appropriate for tropical regions. In the present paper, the 0°C isotherm (ZDI) height has been established using two years of data collected on-board the precipitation radar of the Tropical Rain Measuring Mission (TRMM) satellite. The result shows the seasonal dependence of the 0°C isotherm height. It is observed, among other things, that the height is higher during the wet season as compared to the dry season. Rain induced attenuation at frequencies above 10 GHz is also estimated using the 0°C isotherm height derived for each of the locations over the elevation angle of the NIGCOMSAT-1R in Nigeria.

  12. Cross-Calibration of Earth Observing System Terra Satellite Sensors MODIS and ASTER

    NASA Technical Reports Server (NTRS)

    McCorkel, J.

    2014-01-01

    The Advanced Spaceborne Thermal Emissive and Reflection Radiometer (ASTER) and Moderate Resolution Imaging Spectrometer (MODIS) are two of the five sensors onboard the Earth Observing System's Terra satellite. These sensors share many similar spectral channels while having much different spatial and operational parameters. ASTER is a tasked sensor and sometimes referred to a zoom camera of the MODIS that collects a full-earth image every one to two days. It is important that these sensors have a consistent characterization and calibration for continued development and use of their data products. This work uses a variety of test sites to retrieve and validate intercalibration results. The refined calibration of Collection 6 of the Terra MODIS data set is leveraged to provide the up-to-date reference for trending and validation of ASTER. Special attention is given to spatially matching radiance measurements using prelaunch spatial response characterization of MODIS. Despite differences in spectral band properties and spatial scales, ASTER-MODIS is an ideal case for intercomparison since the sensors have nearly identical views and acquisitions times and therefore can be used as a baseline of intercalibration performance of other satellite sensor pairs.

  13. Lossless compression of images from China-Brazil Earth Resources Satellite

    NASA Astrophysics Data System (ADS)

    Pinho, Marcelo S.

    2011-11-01

    The aim of this work is to evaluate the performance of different schemes of lossless compression when applied to compact images collected by the satellite CBERS-2B. This satellite is the third one constructed under the CBERS Program (China- Brazil Earth Resources Satellite) and it was launched in 2007. This work focuses in the compression of images from the CCD camera which has a resolution of 20 x 20 meters and five bands. CBERS-2B transmits the data from CCD in real time, with no compression and it does not storage even a small part of images. In fact, this satellite can work in this way because the bit rate produced by CCD is smaller than the transmitter bit rate. However, the resolution and the number of spectral bands of imaging systems are increasing and the constrains in power and bandwidth bound the communication capacity of a satellite channel. Therefore, in the future satellites the communication systems must be reviewed. There are many algorithms for image compression described in the literature and some of them have already been used in remote sensing satellites (RSS). When the bit rate produced by the imaging system is much higher than the transmitter bit rate, a lossy encoder must be used. However, when the gap between the bit rates is not so high, a lossless procedure can be an interesting choice. This work evaluates JPEG-LS, CALIC, SPIHT, JPEG2000, CCSDS recommendation, H.264, and JPEG-XR when they are used to compress images from the CCD camera of CBERS-2B with no loss. The algorithms are applied in a set of twenty images with 5, 812 x 5, 812 pixels, running in blocks of 128 x 128; 256 x 256; 512 x 512; and 1, 024x1, 024 pixels. The tests are done independently in each original band and also in five transformed bands, obtained by a procedure which decorrelates them. In general, the results have shown that algorithms based on predictive schemes (CALIC and JPEG-LS) applied in transformed decorrelated bands produces a better performance in the mean

  14. Impacts of artificial ocean alkalinization on the carbon cycle and climate in Earth system simulations

    NASA Astrophysics Data System (ADS)

    González, Miriam Ferrer; Ilyina, Tatiana

    2016-06-01

    Using the state-of-the-art emissions-driven Max Planck Institute Earth system model, we explore the impacts of artificial ocean alkalinization (AOA) with a scenario based on the Representative Concentration Pathway (RCP) framework. Addition of 114 Pmol of alkalinity to the surface ocean stabilizes atmospheric CO2 concentration to RCP4.5 levels under RCP8.5 emissions. This scenario removes 940 GtC from the atmosphere and mitigates 1.5 K of global warming within this century. The climate adjusts to the lower CO2 concentration preventing the loss of sea ice and high sea level rise. Seawater pH and the carbonate saturation state (Ω) rise substantially above levels of the current decade. Pronounced differences in regional sensitivities to AOA are projected, with the Arctic Ocean and tropical oceans emerging as hot spots for biogeochemical changes induced by AOA. Thus, the CO2 mitigation potential of AOA comes at a price of an unprecedented ocean biogeochemistry perturbation with unknown ecological consequences.

  15. Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization

    USGS Publications Warehouse

    Smith, W. Kolby; Reed, Sasha C.; Cleveland, Cory C.; Ballantyne, Ashley P; Anderegg, William R. L.; Wieder, William R.; Liu, Yi Y; Running, Steven W.

    2015-01-01

    Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, ‘CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data, we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.

  16. Forecasting the impact of an 1859-caliber superstorm on geosynchronous Earth-orbiting satellites: Transponder resources

    NASA Astrophysics Data System (ADS)

    Odenwald, Sten F.; Green, James L.

    2007-06-01

    We calculate the economic impact on the existing geosynchronous Earth-orbiting satellite population of an 1859-caliber superstorm event were it to occur between 2008 and 2018 during the next solar activity cycle. From a detailed model for transponder capacity and leasing, we have investigated the total revenue loss over the entire solar cycle, as a function of superstorm onset year and intensity. Our Monte Carlo simulations of 1000 possible superstorms, of varying intensity and onset year, suggest that the minimum revenue loss could be of the order of 30 billion. The losses would be larger than this if more that 20 satellites are disabled, if future launch rates do not keep up with the expected rate of retirements, or if the number of spare transponders falls below ˜30%. Consequently, revenue losses can be significantly reduced below 30 billion if the current satellite population undergoes net growth beyond 300 units during Solar Cycle 24 and a larger margin of unused transponders is maintained.

  17. KAGLVis - On-line 3D Visualisation of Earth-observing-satellite Data

    NASA Astrophysics Data System (ADS)

    Szuba, Marek; Ameri, Parinaz; Grabowski, Udo; Maatouki, Ahmad; Meyer, Jörg

    2015-04-01

    One of the goals of the Large-Scale Data Management and Analysis project is to provide a high-performance framework facilitating management of data acquired by Earth-observing satellites such as Envisat. On the client-facing facet of this framework, we strive to provide visualisation and basic analysis tool which could be used by scientists with minimal to no knowledge of the underlying infrastructure. Our tool, KAGLVis, is a JavaScript client-server Web application which leverages modern Web technologies to provide three-dimensional visualisation of satellite observables on a wide range of client systems. It takes advantage of the WebGL API to employ locally available GPU power for 3D rendering; this approach has been demonstrated to perform well even on relatively weak hardware such as integrated graphics chipsets found in modern laptop computers and with some user-interface tuning could even be usable on embedded devices such as smartphones or tablets. Data is fetched from the database back-end using a ReST API and cached locally, both in memory and using HTML5 Web Storage, to minimise network use. Computations, calculation of cloud altitude from cloud-index measurements for instance, can depending on configuration be performed on either the client or the server side. Keywords: satellite data, Envisat, visualisation, 3D graphics, Web application, WebGL, MEAN stack.

  18. Use of negotiated rulemaking in developing technical rules for low-Earth orbit mobile satellite systems

    NASA Technical Reports Server (NTRS)

    Taylor, Leslie A.

    1993-01-01

    Technical innovations have converged with the exploding market demand for mobile telecommunications to create the impetus for low-earth orbit (LEO) communications satellite systems. The so-called 'Little LEO's' propose use of VHF and UHF spectrum to provide position - location and data messaging services. The so-called 'Big LEO's' propose to utilize the RDSS bands to provide voice and data services. In the United States, several applications were filed with the U.S. Federal Communications Commission (FCC) to construct and operate these mobile satellite systems. To enable the prompt introduction of such new technology services, the FCC is using innovative approaches to process the applications. Traditionally, when the FCC is faced with 'mutually exclusive' applications, e.g. a grant of one would preclude a grant of the others, it uses selection mechanisms such as comparative hearings or lotteries. In the case of the LEO systems, the FCC has sought to avoid these time-consuming approaches by using negotiated rulemakings. The FCC's objective is to enable the multiple applicants and other interested parties to agree on technical and service rules which will enable the grant of all qualified applications. With regard to the VHF/UHF systems, the Advisory Committee submitted a consensus report to the FCC. The process for the systems operating in the bands above 1 GHz involved more parties and more issues but still provided the FCC useful technical information to guide the adoption of rules for the new mobile satellite service.

  19. From Earth to Heaven: Using `Newton's Cannon' Thought Experiment for Teaching Satellite Physics

    NASA Astrophysics Data System (ADS)

    Velentzas, Athanasios; Halkia, Krystallia

    2013-10-01

    Thought Experiments are powerful tools in both scientific thinking and in the teaching of science. In this study, the historical Thought Experiment (TE) `Newton's Cannon' was used as a tool to teach concepts relating to the motion of satellites to students at upper secondary level. The research instruments were: (a) a teaching-interview designed and implemented according to the Teaching Experiment methodology and (b) an open-ended questionnaire administered to students 2 weeks after the teaching-interview. The sample consisted of forty students divided into eleven groups. The teaching and learning processes which occurred during the teaching-interview were recorded and analyzed. The findings of the present study show that the use of the TE helped students to mentally construct a physical system which has nothing to do with their everyday experience (i.e. they had to imagine themselves as observers in a context in which the whole Earth was visible) and to draw conclusions about phenomena within this system. Specifically, students managed (1) to conclude that if an object is appropriately launched, it may be placed in an orbit around the Earth and to support this conclusion by giving necessary arguments, and (2) to realize that the same laws of physics describe, on the one hand, the motion of the Moon around the Earth (and the motion of other celestial bodies as well) and, on the other hand, the motion of `terrestrial' objects (i.e. objects on the Earth, such as a tennis ball). The main difficulties students met were caused by their idea that there is no gravity in the vacuum (i.e. the area outside of the Earth's atmosphere) and also by their everyday experience, according to which it is impossible for a projectile to move continuously parallel to the ground.

  20. Small Satellites for Atmospheric and near earth Space sciences - the Indian perspectives of a low cost access to Space

    NASA Astrophysics Data System (ADS)

    Sridharan, R.

    Small satellites of 100-400 kg class are expected to play bigger roles in the years to come. With the advancement of technology in terms of miniaturization and also reliability, it has become possible to configure small satellites which otherwise would have demanded larger platforms, both in terms of weight and power. The atmospheric and near Earth space processes are truly multi-dimensional and are extremely complex with large temporal and spatial variability and also respond closely to the processes in the Sun. As a consequence, no single satellite mission would be able to provide the complete information thus warranting multiple missions. With the successful demonstration of multiple satellites launching capability, the spare capacity of the launch vehicles could be effectively and judiciously used for launching dedicated small scientific satellites as co passengers with negligible cost factor. This is viewed as an opening up of an otherwise difficult opportunity involving dedicated launches. With the prospect of multiple satellites for science missions becoming a reality the overall mission with an active life of 2-3 years could be realized with judicious choice of components. This is expected to bring in a larger user community in the country. The first step in this direction is the configuration of a modular micro and small satellite bus. The upcoming missions of TWSAT (Third world satellite), Youth Sat (active participation of the student community), SARAL (Satellite for ARGOs and Altimetry), SENSE/E and SENSE/P (Satellite for Earth's Near Space environment), ISTAG (Indian Satellite for Aerosols and Gases), are utilizing the above concepts. ISRO has also come out with AO's for Astronomy and Astrophysics payloads, as most of the stringent requirements of various experiments could be met with the small satellite platforms themselves. A brief outline of the upcoming and proposed activities would be presented and discussed in the talk.

  1. New developments in the coordination of Earth observation from space activities: The role of the Committee on Earth Observations Satellites (CEOS)

    NASA Technical Reports Server (NTRS)

    Smith, B.; Moodie, L.; Shaffer, L.; Williams, D.; Revah, I.

    1992-01-01

    The Committee on Earth Observations Satellites (CEOS) is outlined and the dynamics of the expanded CEOS with its increased focus on activities related to global climate change are examined. The participation of affiliate organizations at the Dec. 1991 Plenary is highlighted. The roles and current activities of constituted CEOS Working Groups on Data and on Sensor Calibration and Performance Validation are examined. The status of CEOS deliberations in Earth observation data policy is examined. The expanded CEOS is believed to be well suited to carry forward and help further the legacy already well established in the myriad of Earth observation activities associated with the 1992 International Space Year.

  2. Techniques to minimize adjacent band emissions from Earth Exploration Satellites to protect the Space Research (Category B) Earth Stations in the 8400-8450 MHz band

    NASA Technical Reports Server (NTRS)

    Wang, Charles C.; Sue, Miles K.; Manshadi, Farzin

    2004-01-01

    The Earth Exploration Satellites operating in the 8025-8400 MHz band can have strong adjacent band emissions on the8400-8450 MHz band which is allocated for Space Research (Category-B). The unwanted emission may exceed the protection criterion establish by the ITU-R for the protection of the Space Research (Category B) earth stations, i.e., deep-space earth stations. An SFCG Action Item (SF 23/14) was created during the 23rd SFCG meeting to explore technical and operational techniques to reduce the adjacent band emissions. In response to this action item, a study was conducted and results are presented in this document.

  3. The EOS Aqua/Aura Experience: Lessons Learned on Design, Integration, and Test of Earth-Observing Satellites

    NASA Technical Reports Server (NTRS)

    Nosek, Thomas P.

    2004-01-01

    NASA and NOAA earth observing satellite programs are flying a number of sophisticated scientific instruments which collect data on many phenomena and parameters of the earth's environment. The NASA Earth Observing System (EOS) Program originated the EOS Common Bus approach, which featured two spacecraft (Aqua and Aura) of virtually identical design but with completely different instruments. Significant savings were obtained by the Common Bus approach and these lessons learned are presented as information for future program requiring multiple busses for new diversified instruments with increased capabilities for acquiring earth environmental data volume, accuracy, and type.

  4. Basic research and data analysis for the earth and ocean physics applications program and for the National Geodetic Satellite program

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Data acquisition using single image and seven image data processing is used to provide a precise and accurate geometric description of the earth's surface. Transformation parameters and network distortions are determined, Sea slope along the continental boundaries of the U.S. and earth rotation are examined, along with close grid geodynamic satellite system. Data are derived for a mathematical description of the earth's gravitational field; time variations are determined for geometry of the ocean surface, the solid earth, gravity field, and other geophysical parameters.

  5. True Color Images of the Earth created with the Geostationary Satellite Instrument MSG SEVIRI

    NASA Astrophysics Data System (ADS)

    Reuter, Maximilian

    2013-04-01

    One of the most famous pictures ever taken was by the crew of Apollo 17 in 1972, showing our Earth from a distance of about 45000km. This picture was named 'Blue Marble' and it reminds us of the beauty and uniqueness of our home planet. With geostationary satellites, such views of the Earth are possible without the need to have a photographer in space. However, up to the present, the production of such Blue Marble type images from geostationary satellite data has been impaired by the lack of channels in the visible spectral region. A method for the generation of full disk MSG (METEOSAT Second Generation) SEVIRI (Scanning-Enhanced Visible and Infrared Imager) true colour composite images will be presented. The algorithm mainly uses the SEVIRI channels VIS006 (0.6μm), NIR008 (0.8μm) and NIR016 (1.6μm). The lack of information in the blue and green parts of the visible spectrum is compensated by using data from NASA's (National Aeronautics and Space Administration's) Blue Marble next generation (BMNG) project to fill a look-up table (LUT) transforming RGB (red/green/blue) false colour composite images of VIS006/NIR008/NIR016 into true colour images. Tabulated radiative transfer calculations of a pure Rayleigh atmosphere are used to add an impression of Rayleigh scattering towards the sunlit horizon. The resulting images satisfy naive expectations: clouds are white or transparent, vegetated surfaces are greenish, deserts are sandy-coloured, the ocean is dark blue to black and a narrow halo due to Rayleigh scattering is visible at the sunlit horizon. Therefore, such images are easily interpretable also for inexperienced users not familiar with the characteristics of typical MSG false colour composite images. The images can be used for scientific applications to illustrate specific meteorological conditions or for non-scientific purposes, for example, for raising awareness in the public of the Earth's worthiness of protection.

  6. Continental Land Mass Air Traffic Control (COLM ATC). [using three artificial satellite configurations

    NASA Technical Reports Server (NTRS)

    Pecar, J. A.; Henrich, J. E.

    1973-01-01

    The application of various satellite systems and techniques relative to providing air traffic control services for the continental United States was studied. Three satellite configurations were reviewed. The characteristics and capabilities of the satellites are described. The study includes consideration for the various ranging waveforms, multiple access alternatives, and the power and bandwidth required as a function of the number of users.

  7. Satellites

    SciTech Connect

    Burns, J.A.; Matthews, M.S.

    1986-01-01

    The present work is based on a conference: Natural Satellites, Colloquium 77 of the IAU, held at Cornell University from July 5 to 9, 1983. Attention is given to the background and origins of satellites, protosatellite swarms, the tectonics of icy satellites, the physical characteristics of satellite surfaces, and the interactions of planetary magnetospheres with icy satellite surfaces. Other topics include the surface composition of natural satellites, the cratering of planetary satellites, the moon, Io, and Europa. Consideration is also given to Ganymede and Callisto, the satellites of Saturn, small satellites, satellites of Uranus and Neptune, and the Pluto-Charon system.

  8. Gravitational mechanism of active life of the Earth, planets and satellites

    NASA Astrophysics Data System (ADS)

    Barkin, Yury

    2010-05-01

    From positions of geodynamic model of the forced gravitational swing, wobble and displacements of shells of a planet are studied and fundamental problems of geodynamics, geology, geophysics, planetary sciences are solved etc.: 1) The mechanism of cyclic variations of activity of natural processes in various time scales. 2) The power of endogenous activity of planetary natural processes on planets and satellites. 3) The phenomenon of polar inversion of natural processes on planets and satellites. 4) Spasmodic and catastrophic changes of activity of natural processes. 5) The phenomenon of twisting of hemispheres (latitude zones or belts) of celestial bodies. 6) Formation of the pear-shaped form of celestial bodies and the mechanism of its change. 7) The ordered planetary structures of geological formations. 8) The phenomena of bipolarity of celestial bodies and antipodality of geology formations. Mechanism. The fundamental feature of a structure of celestial bodies is their shell structure. The most investigated is the internal structure of the Earth. For the Moon and wide set of other bodies of solar system models of an internal structure have been constructed on the basis of the data of observations obtained at studying of their gravitational fields as a result of realization of the appropriate space missions. The basic components for the majority of celestial bodies are the core, the mantle and the crust. To other shells we concern atmospheres (for example, at Venus, Mars, the Titan etc.) and oceanic shells (the Titan, the Earth, Enceladus etc.). Shells are the complex (composite) formations. Planets and satellites are not spherical celestial bodies. The centers of mass of shells of the given planet (or the satellite) and their appropriate principal axes of inertia do not coincide. Accordingly, all their shells are characterized by the certain dynamic oblatenesses. Differences of dynamical oblatenesses results in various forced influences of external celestial

  9. K-Band Phased Array Developed for Low- Earth-Orbit Satellite Communications

    NASA Technical Reports Server (NTRS)

    Anzic, Godfrey

    1999-01-01

    Future rapid deployment of low- and medium-Earth-orbit satellite constellations that will offer various narrow- to wide-band wireless communications services will require phased-array antennas that feature wide-angle and superagile electronic steering of one or more antenna beams. Antennas, which employ monolithic microwave integrated circuits (MMIC), are perfectly suited for this application. Under a cooperative agreement, an MMIC-based, K-band phased-array antenna is being developed with 50/50 cost sharing by the NASA Lewis Research Center and Raytheon Systems Company. The transmitting array, which will operate at 19 gigahertz (GHz), is a state-of-the-art design that features dual, independent, electronically steerable beam operation ( 42 ), a stand-alone thermal management, and a high-density tile architecture. This array can transmit 622 megabits per second (Mbps) in each beam from Earth orbit to small Earth terminals. The weight of the total array package is expected to be less than 8 lb. The tile integration technology (flip chip MMIC tile) chosen for this project represents a major advancement in phased-array engineering and holds much promise for reducing manufacturing costs.

  10. Mapping the mass distribution of Earth's mantle using satellite-derived gravity gradients

    NASA Astrophysics Data System (ADS)

    Panet, Isabelle; Pajot-Métivier, Gwendoline; Greff-Lefftz, Marianne; Métivier, Laurent; Diament, Michel; Mandea, Mioara

    2014-02-01

    The dynamics of Earth's mantle are not well known. Deciphering mantle flow patterns requires an understanding of the global distribution of mantle density. Seismic tomography has been used to derive mantle density distributions, but converting seismic velocities into densities is not straightforward. Here we show that data from the GOCE (Gravity field and steady-state Ocean Circulation Explorer) mission can be used to probe our planet's deep mass structure. We construct global anomaly maps of the Earth's gravitational gradients at satellite altitude and use a sensitivity analysis to show that these gravitational gradients image the geometry of mantle mass down to mid-mantle depths. Our maps highlight north-south-elongated gravity gradient anomalies over Asia and America that follow a belt of ancient subduction boundaries, as well as gravity gradient anomalies over the central Pacific Ocean and south of Africa that coincide with the locations of deep mantle plumes. We interpret these anomalies as sinking tectonic plates and convective instabilities between 1,000 and 2,500km depth, consistent with seismic tomography results. Along the former Tethyan Margin, our data also identify an east-west-oriented mass anomaly likely in the upper mantle. We suggest that by combining gravity gradients with seismic and geodynamic data, an integrated dynamic model for Earth can be achieved.

  11. A computer program for mapping satellite-borne narrow-beam antenna footprints on earth

    NASA Technical Reports Server (NTRS)

    Stagl, T. W.; Singh, J. P.

    1972-01-01

    A computer program has been developed that computes the locus of intersection of a quadric cone and a sphere. The outputs of the program are a list of the longitude and latitude coordinates of the locus of intersection and a plot of the locus. It was written primarily to define the area of the earth covered by a narrow beam antenna carried on a synchronous satellite in circular, near equatorial orbits. The program was written for use with a CalComp 570/563 off-line plotting system and uses the standard CalComp subroutines supplied with the system. The plot is drawn using linear longitude and latitude scales and nonlinear scales such as Mercator scales cannot be used. It should be noted that this program assumes the earth to be spherical rather than oblate is it actually is. However, by assuming a spherical earth, maximum error distances of about 11.5 nautical miles are introduced. For many purposes, this error can be ignored.

  12. CEOS WGISS Integrated Catalog, A Catalog for Earth Observation Satellite Data

    NASA Astrophysics Data System (ADS)

    Enloe, Y.; Yapur, M.

    2011-12-01

    The Committee on Earth Observation Satellites (CEOS) was formed in 1984 to coordinate the world's civil space-borne observations of the Earth. More recently, CEOS and its member agencies have committed to provide the implementation of the space-based component of the Group on Earth Observation (GEO) Global Earth Observation System of Systems (GEOSS) Common Infrastructure (GCI). In the case of CEOS, there are a number of challenges in directly connecting the components and services of its member agencies to the GCI. In many cases, the existing catalog systems of the member agencies do not support the OGC Catalog Service for the Web (CSW) that has been selected as the standard for the GCI. Another challenge is related to the fact that collections of satellite data products are extremely large and constantly growing with millions of individual products. Harvesting the associated metadata into the clearinghouse of the GCI is not a practical alternative. In addition, the collection/granule hierarchy and unique spatial/temporal characteristics of satellite data and the user registration and asynchronous access requirements of the agency systems pose additional challenges. The CEOS approach has been to design and implement a CEOS WGISS Integrated Catalog (CWIC) that will serve as a community catalog of the products and services that are offered through its member's systems. CWIC will be based on a distributed search architecture and serve as a gateway between the GEO portal or community portals and clients and the CEOS agency systems. CWIC will receive standard search queries from these portals or clients all using the GEO supported catalog standard, the OGC CSW 2.0.2 and the WGISS Search Criteria for granule search and translate them into the native protocols of the underlying catalogs. Likewise, the result sets from the CEOS agency catalogs will be converted to the form that will be compatible with the portals and clients. The CWIC data provider partners include NOAA

  13. Global satellite triangulation and trilateration for the National Geodetic Satellite Program (solutions WN 12, 14 and 16). [study and analysis of data from artificial satellites

    NASA Technical Reports Server (NTRS)

    Mueller, I. I.; Kumar, M.; Reilly, J. P.; Saxena, N.; Soler, T.

    1973-01-01

    A multi-year study and analysis of data from satellites launched specifically for geodetic purposes and from other satellites useful in geodetic studies was conducted. The program of work included theoretical studies and analysis for the geometric determination of station positions derived from photographic observations of both passive and active satellites and from range observations. The current status of data analysis, processing and results are examined.

  14. Results of the Calibration of the Delays of Earth Stations for TWSTFT Using the VSL Satellite Simulator Method

    NASA Technical Reports Server (NTRS)

    deJong, Gerrit; Kirchner, Dieter; Ressler, Hubert; Hetzel, Peter; Davis, John; Pears, Peter; Powell, Bill; McKinley, Angela Davis; Klepczynski, Bill; DeYoung, James; Hackman, Christine; Jefferts, Steve R.; Parker, Thomas E.

    1996-01-01

    Two-way satellite time and frequency transfer (TWSTFT) is the most accurate and precise method of comparing two remote clocks or time scales. The accuracy obtained is dependent on the accuracy of the determination of the non-reciprocal delays of the transmit and the receive paths. When the same transponders in the satellite at the same frequencies are used, then the non-reciprocity in the Earth stations is the limiting factor for absolute time transfer.

  15. An Attitude Control System for SumbandilaSAT an Earth Observation Satellite

    NASA Astrophysics Data System (ADS)

    Steyn, W. H.

    2008-08-01

    This paper describes the attitude determination and control system to support the multi-spectral earth observation main payload of the SumbandilaSAT microsatellite. The satellite has only a single main Y- body mounted solar panel and the attitude control system must ensure a nominal sun-pointed attitude under all non-imaging conditions during the sunlit part of the orbit. The control actuators employed are 3- axis magnetic torquer rods and reaction wheels. During initial detumbling and safe mode operations a simple new magnetic control law is used to bring the satellite to a sun-pointed Y-spinning attitude for maximum solar power collection. From this sun-pointed, spinning attitude an intermediate control mode is entered when the Y-reaction wheel is utilised as a momentum wheel, to absorb the body spin rate and to inertially stabilise the angular momentum vector towards the sun direction. During the intermediate mode the magnetic rods are used to maintain the momentum vector size and direction and to do nutation damping. The pitch angle is also controlled using the Y-wheel, to keep the main imager payload as close as possible to an earth-pointed attitude and to thermally stabilise the imager telescope. The final and nominal attitude control mode is entered when a zero biased 3-axis reaction wheel controller is enabled, for: 1) sun tracking for optimal solar power collection, 2) target tracking during viewfinder use or during imaging download communication with a ground station and 3) pushbroom imager scanning with a forward motion compensation capability. During the nominal mode the magnetic rods are used to dump the angular momentum from the reaction wheels during sun tracking periods. A short introduction to the Sumbandila satellite will be given. All the control modes, the attitude sensors and estimators utilised, will be introduced in the paper. Specifically, a unique agile viewfinder control mode to manually select targets for subsequent high resolution image

  16. Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 2: EOS-A system specification

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The objectives of the Earth Observatory Satellite (EOS) program are defined. The system specifications for the satellite payload are examined. The broad objectives of the EOS-A program are as follows: (1) to develop space-borne sensors for the measurement of land resources, (2) to evolve spacecraft systems and subsystems which will permit earth observation with greater accuracy, coverage, spatial resolution, and continuity than existing systems, (3) to develop improved information processing, extraction, display, and distribution systems, and (4) to use space transportation systems for resupply and retrieval of the EOS.

  17. Variations of the Earth's figure axis from satellite laser ranging and GRACE

    NASA Astrophysics Data System (ADS)

    Cheng, Minkang; Ries, John C.; Tapley, Byron D.

    2011-01-01

    Satellite laser ranging (SLR) data were used to determine the variations in the Earth's principal figure axis represented by the degree 2 and order 1 geopotential coefficients: C21 and S21. Significant variations at the annual and Chandler wobble frequencies appear in the SLR time series when the rotational deformation or "pole tides" (i.e., the solid Earth and ocean pole tides) were not modeled. The contribution of the ocean pole tide is estimated to be only ˜8% of the total annual variations in the normalized coefficients: ?/? based on the analysis of SLR data. The amplitude of the nontidal annual variation of ? is only ˜ 30% of ? from the SLR time series. The estimates of the annual variation in ? from SLR, the Gravity Recovery and Climate Experiment (GRACE) and polar motion excitation function, are in a good agreement. The nature of the linear trend for the Earth's figure axis determined by these techniques during the last several years is in general agreement but does not agree as well with results predicted from current glacial isostatic adjustment (GIA) models. The "fluid Love number" for the Earth is estimated to be ˜0.9 based on the position of the mean figure axis from the GRACE gravity model GGM03S and the mean pole defined by the IERS 2003 conventions. The estimate of ?/? from GRACE and SLR provides an improved constraint on the relative rotation of the core. The results presented here indicate a possible tilt of the inner core figure axis of ˜2° and ˜3 arc sec displacement for the figure axis of the entire core.

  18. The Transiting Exoplanet Survey Satellite (TESS): Discovering New Earths and Super-Earths in the Solar Neighborhood

    NASA Astrophysics Data System (ADS)

    Ricker, George R.

    2015-12-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In its two-year prime survey mission, TESS will monitor more than 200,000 bright stars in the solar neighborhood for temporary drops in brightness caused by planetary transits. This first-ever spaceborne all-sky transit survey will identify planets ranging from Earth-sized to gas giants, around a wide range of stellar types and orbital distances.TESS stars will typically be 30-100 times brighter than those surveyed by the Kepler satellite; thus, TESS planets will be far easier to characterize with follow-up observations. For the first time it will be possible to study the masses, sizes, densities, orbits, and atmospheres of a large cohort of small planets, including a sample of rocky worlds in the habitable zones of their host stars.An additional data product from the TESS mission will be full frame images (FFI) with a cadence of 30 minutes or less. These FFI will provide precise photometric information for every object within the 2300 square degree instantaneous field of view of the TESS cameras. These objects will include more than 1 million stars and bright galaxies observed during sessions of several weeks. In total, more than 30 million objects brighter than I=16 will be precisely photometered during the two-year prime mission. In principle, the lunar-resonant TESS orbit could provide opportunities for an extended mission lasting more than a decade, with data rates in excess of 100 Mbits/s.An extended survey by TESS of regions surrounding the North and South Ecliptic Poles will provide prime exoplanet targets for characterization with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future.TESS will issue data releases every 4 months, inviting immediate community-wide efforts to study the new planets, as well as commensal survey candidates from the FFI. A NASA Guest

  19. Four identical satellites investigating the Earth's turbulent relationship with the Sun

    NASA Astrophysics Data System (ADS)

    1996-05-01

    Once in space, the four satellites will manoeuvre to an eccentric polar trajectory along which they will fly in tetrahedral formation for the next two years. They will take highly precise and, for the first time, three- dimensional measurements of the extraordinarily dynamic phenomena that occur where the solar wind meets the near- Earth environment. They will gather an unprecedented volume of very high- quality information on the magnetic storms, electric currents and particle accelerations that take place in the space surrounding our planet, which give rise to all manner of events, such as the aurorae in the polar regions, power cuts, breakdowns in telecommunication systems, or satellite malfunctions, and perhaps even changes in climate. The Cluster mission will also gather a host of fundamental information on the ionised gases whose behaviour physicists are trying to reproduce under laboratory conditions with the ultimate aim of generating thermonuclear energy. A cosmic battlefield The Sun's flames are lapping at the Earth's doorstep. In its constant state of effervescence/evaporation, it emits into space a wind charged with ions, electrons and protons which reach Earth at speeds of 1.5 to 3 million kph. Fortunately, our planet is armed with a natural shield against this onslaught: the magnetosphere, a distant magnetic, ionised extension of our atmosphere which slows and deflects the bulk of the stream of particles emitted by the Sun. This shield does not provide complete protection, however. Under constant buffeting from the interplanetary wind, the "fluid" magnetic screen is buckled, distorted and occasionally torn, causing small holes. When this happens, intense electric currents, magnetic storms and particle accelerations immediately develop. The overall interaction between the solar wind and the magnetosphere is so violent that the energy transferred can be as much as 1013 watts - equivalent to worldwide power consumption - and the currents induced run to

  20. RELEC Experiment on board Vernov Satellite: Relativistic Electron Flux Dynamics in Near-Earth Space

    NASA Astrophysics Data System (ADS)

    Svertilov, Sergiey

    2015-04-01

    The main goal of RELEC mission is study of magnetosphere relativistic electron precipitation with it possible acting on the upper atmosphere and ionosphere as well as the monitor observation of radiation and electromagnetic environment in the near-Earth Space. The RELEC set of instruments includes two identical detectors of X- and gamma-rays of high temporal resolution and sensitivity (DRGE-1 & DRGE-2), three axe directed detectors of energetic electrons and protons DRGE-3, UV TLE imager MTEL, UV detector DUV, low-frequency analyser LFA, radio-frequency analyser RFA, module of electronics intended for commands and data collection BE. The small satellite now named Vernov with RELEC instruments was successfully launched July, 8 2014. The mission orbit is solar-synchronous with apogee 830 km, perigee 640 km, inclination 98.4o and orbital period about 100 min. The total data output is about 1.2 Gbyte per day. The fluxes and spectra of electrons in the wide energy range from 0.2 to 15 MeV are measured with the use of three detectors with axe normally directed to each other: to the local zenith, opposite to the satellite velocity vector and along the direction added two previous to the Cartesian system. Due to such detector system it is possible to estimate the electron flux anisotropy. The wide dynamical range from ~1 up to 104 part/cm2s and fine time resolution (~10 mcs) allows observations of trapped, quasi-trapped and precipitated electron flux and spectral variations in different areas in the near-Earth space including low L-shells. Comparative analysis of electron fluxes measured by RELEC with experimental data on electron detection in the experiments on board the spacecraft Electro-L with geostationary orbit, and Meteor-M2 with 800 km altitude circular polar orbit similar to Vernov allows to reconstruct the energetic electron spatial distribution in the near-Earth space. A comparison will be held for periods of moderate geomagnetic disturbances of August 26

  1. Protection of passive radio frequencies used for earth exploration by satellite

    NASA Astrophysics Data System (ADS)

    Rochard, Guy

    2004-10-01

    Space-borne passive sensing of the Earth"s surface and atmosphere has an essential and increasing importance in Earth Observation. The impressive progress recently made or shortly expected in weather analysis, warning and forecasts (in particular for dangerous weather phenomena as rain and floods, storms, cyclones, droughts) as well as in the study and prediction of climate change, is mainly attributable to the spaceborne observations. On this basis, economic studies show that meteorological services have a high positive impact on a wide range of economic activities, notwithstanding safety of life and property aspects. Space-borne passive sensing feeds crucial observational data to numerical weather predction models run on the most advanced super-computers that are operated by a few global forecasting centers. All meteorological and environmental satellite organizations operate these crucial remote-sensing missions as part of the GOS of the World Weather Watch and others... Spaceborne passive sensing for meterological applications is performed in frequency bands allocated to the Earth Exploration-Satellite Service. This is named "EESS passive" in the ITU-R Radio Regulations. The appropriate bands are uniquely determined by the physical properties (e.g. molecular resonance) of constituents of the atmosphere, and are therefore one of the unique natural resources (similarly to Radio Astronomy bands). Passive measurements at several frequencies in the microwave spectrum must be made simultaneously in order to extract the individual contribution of the geophysical parameter of interest. Bands below 100 GHz are of particular importance to provide an "all-weather" capability since many clouds are almost transparent at these frequencies. Along this line, the two first figures below about zenithal opacity describes respectively the atmosphere optical thickness due to water vapor and dry components in the frequency range 1 to 275 GHz and 275 GHz to 1000 GHz on which have

  2. Design/cost tradeoff studies. Appendix A. Supporting analyses and tradeoffs, book 1. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A listing of the Earth Observatory Satellite (EOS) candidate missions is presented for use as a baseline in describing the EOS payloads. The missions are identified in terms of first, second, and third generation payloads. The specific applications of the EOS satellites are defined. The subjects considered are: (1) orbit analysis, (2) space shuttle interfaces, (3) thematic mapping subsystem, (4) high resolution pointable imager subsystem, (5) the data collection system, (6) the synthetic aperture radar, (7) the passive multichannel microwave radiometer, and (8) the wideband communications and handling equipment. Illustrations of the satellite and launch vehicle configurations are provided. Block diagrams of the electronic circuits are included.

  3. A Comparison of Techniques for Scheduling Fleets of Earth-Observing Satellites

    NASA Technical Reports Server (NTRS)

    Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

    2003-01-01

    Earth observing satellite (EOS) scheduling is a complex real-world domain representative of a broad class of over-subscription scheduling problems. Over-subscription problems are those where requests for a facility exceed its capacity. These problems arise in a wide variety of NASA and terrestrial domains and are .XI important class of scheduling problems because such facilities often represent large capital investments. We have run experiments comparing multiple variants of the genetic algorithm, hill climbing, simulated annealing, squeaky wheel optimization and iterated sampling on two variants of a realistically-sized model of the EOS scheduling problem. These are implemented as permutation-based methods; methods that search in the space of priority orderings of observation requests and evaluate each permutation by using it to drive a greedy scheduler. Simulated annealing performs best and random mutation operators outperform our squeaky (more intelligent) operator. Furthermore, taking smaller steps towards the end of the search improves performance.

  4. A Dynamic Scheduling Method of Earth-Observing Satellites by Employing Rolling Horizon Strategy

    PubMed Central

    Dishan, Qiu; Chuan, He; Jin, Liu; Manhao, Ma

    2013-01-01

    Focused on the dynamic scheduling problem for earth-observing satellites (EOS), an integer programming model is constructed after analyzing the main constraints. The rolling horizon (RH) strategy is proposed according to the independent arriving time and deadline of the imaging tasks. This strategy is designed with a mixed triggering mode composed of periodical triggering and event triggering, and the scheduling horizon is decomposed into a series of static scheduling intervals. By optimizing the scheduling schemes in each interval, the dynamic scheduling of EOS is realized. We also propose three dynamic scheduling algorithms by the combination of the RH strategy and various heuristic algorithms. Finally, the scheduling results of different algorithms are compared and the presented methods in this paper are demonstrated to be efficient by extensive experiments. PMID:23690742

  5. A dynamic scheduling method of Earth-observing satellites by employing rolling horizon strategy.

    PubMed

    Dishan, Qiu; Chuan, He; Jin, Liu; Manhao, Ma

    2013-01-01

    Focused on the dynamic scheduling problem for earth-observing satellites (EOS), an integer programming model is constructed after analyzing the main constraints. The rolling horizon (RH) strategy is proposed according to the independent arriving time and deadline of the imaging tasks. This strategy is designed with a mixed triggering mode composed of periodical triggering and event triggering, and the scheduling horizon is decomposed into a series of static scheduling intervals. By optimizing the scheduling schemes in each interval, the dynamic scheduling of EOS is realized. We also propose three dynamic scheduling algorithms by the combination of the RH strategy and various heuristic algorithms. Finally, the scheduling results of different algorithms are compared and the presented methods in this paper are demonstrated to be efficient by extensive experiments.

  6. Earth Observatory Satellite system definition study. Report no. 6: Space shuttle interfaces/utilization

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The impacts of achieving compatibility of the Earth Observatory Satellite (EOS) with the space shuttle and the potential benefits of space shuttle utilization are discussed. Mission requirements and mission suitability, including the effects of multiple spacecraft missions, are addressed for the full spectrum of the missions. Design impact is assessed primarily against Mission B, but unique requirements reflected by Mission A, B, and C are addressed. The preliminary results indicated that the resupply mission had the most pronounced impact on spacecraft design and cost. Program costs are developed for the design changes necessary to achieve EOS-B compatibility with Space Shuttle operations. Non-recurring and recurring unit costs are determined, including development, test, ground support and logistics, and integration efforts. Mission suitability is addressed in terms of performance, volume, and center of gravity compatibility with both space shuttle and conventional launch vehicle capabilities.

  7. Design/cost tradeoff studies. Earth Observatory Satellite system definition study (EOS)

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The results of design/cost tradeoff studies conducted during the Earth Observatory Satellite system definition studies are presented. The studies are concerned with the definition of a basic modular spacecraft capable of supporting a variety of operational and/or research and development missions, with the deployment either by conventional launch vehicles or by means of the space shuttle. The three levels investigated during the study are: (1) subsystem tradeoffs, (2) spacecraft tradeoffs, and (3) system tradeoffs. The range of requirements which the modular concept must span is discussed. The mechanical, thermal, power, data and electromagnetic compatibility aspects of modularity are analyzed. Other data are provided for the observatory design concept, the payloads, integration and test, the ground support equipment, and ground data management systems.

  8. Earth Resources Technology Satellite data collection project, ERTS - Bolivia. [thematic mapping

    NASA Technical Reports Server (NTRS)

    Brockmann, C. E.

    1974-01-01

    The Earth Resources Technology Satellite program of Bolivia has developed a multidisciplinary project to carry out investigations in cartography and to prepare various thematic maps. In cartography, investigations are being carried out with the ERTS-1 images and with existing maps, to determine their application to the preparation of new cartographic products on one hand and on the other to map those regions where the cartography is still deficient. The application of the MSS images to the geological mapping has given more than satisfactory results. Working with conventional photointerpretation, it has been possible to prepare regional geological maps, tectonic maps, studies relative to mining, geomorphological maps, studies relative to petroleum exploration, volcanological maps and maps of hydrologic basins. In agriculture, the ERTS images are used to study land classification and forest and soils mapping.

  9. Microwave maps of the polar ice of the earth. [from Nimbus-5 satellite

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Wilheit, T. T.; Chang, T. C.; Nordberg, W.; Campbell, W. J.

    1973-01-01

    Synoptic views of the entire polar regions of earth were obtained free of the usual persistent cloud cover using a scanning microwave radiometer operating at a wavelength of 1.55 cm on board the Nimbus-5 satellite. Three different views at each pole are presented utilizing data obtained at approximately one-month intervals during the winter of 1972-1973. The major discoveries resulting from an analysis of these data are as follows: (1) Large discrepancies exist between the climatic norm ice cover depicted in various atlases and the actual extent of the canopies. (2) The distribution of multiyear ice in the north polar region is markedly different from that predicted by existing ice dynamics models. (3) Irregularities in the edge of the Antarctic sea ice pack occur that have neither been observed previously nor anticipated. (4) The brightness temperatures of the Greenland and Antarctica glaciers show interesting contours probably related to the ice and snow morphologic structure.

  10. Extended Kalman filter for attitude estimation of the earth radiation budget satellite

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack Y.

    1989-01-01

    The design and testing of an Extended Kalman Filter (EKF) for ground attitude determination, misalignment estimation and sensor calibration of the Earth Radiation Budget Satellite (ERBS) are described. Attitude is represented by the quaternion of rotation and the attitude estimation error is defined as an additive error. Quaternion normalization is used for increasing the convergence rate and for minimizing the need for filter tuning. The development of the filter dynamic model, the gyro error model and the measurement models of the Sun sensors, the IR horizon scanner and the magnetometers which are used to generate vector measurements are also presented. The filter is applied to real data transmitted by ERBS sensors. Results are presented and analyzed and the EKF advantages as well as sensitivities are discussed. On the whole the filter meets the expected synergism, accuracy and robustness.

  11. New modulation techniques for low-cost power and bandwidth efficient satellite earth stations

    NASA Astrophysics Data System (ADS)

    Le-Ngoc, T.; Pham van, H.

    1982-01-01

    New power and bandwidth efficient modulation techniques, named intersymbol interference and jitter-free (IJF)-QPSK and IJF-OQPSK, are presented. The properties of the IJF-QPSK and IJF-OQPSK signals in linear and nonlinear earth-station-satellite systems are studied. A finite-state Markov chain model is used to calculate power spectra of hard-limited IJF-QPSK and IJF-OQPSK. The results indicate that the IJF-OQPSK modulated signal exhibits much less spectrum spreading than QPSK, OQPSK, and MSK. The error probability performance of IJF-QPSK and IJF-OQPSK in an additive white Gaussian noise and adjacent-channel interference environment is evaluated. The results show that the error probability performance of the IJF-OQPSK is superior to that of QPSK, OQPSK, and MSK in narrow-band nonlinear channels.

  12. Earth-satellite path attenuation statistics influenced by orientation of rain cells

    NASA Technical Reports Server (NTRS)

    Goldhirsh, J.

    1977-01-01

    It is examined whether there may be preferred azimuths for earth-satellite paths along which fading and space diversity statistics are influenced differently than along other azimuths. Such preferred directions may exist if individual rain cells are statistically elongated along them for the given climatological region. The analysis is performed using the rain reflectivity data base obtained at Wallops Island during June, July and August 1973 using a high resolution radar. It is found that in the vicinity of Wallops Island increased attenuation and poorer diversity gains exist along paths whose azimuths and base lines lie in the NE-SW quadrants as compared to the NW-SE sectors. This result suggests the dominance of the major axis of rain cells in these quadrants.

  13. Low-cost, high-resolution telescopes for imaging low-earth orbit satellites

    SciTech Connect

    Massie, N.A.B.; Oster, Y.; Poe, G.; Seppala, L. ); Shao, M. )

    1989-01-01

    Telescopes designed for non-conventional imaging of near-earth satellites must follow a unique set of design rules. Cost must be reduced substantially and the design must accommodate a technique to circumvent the atmospheric distortions of the image. Apertures to 12 meters and beyond are required along with alt-alt mounts providing high tracking rates. A novel design for such a telescope has been generated which is optimized for speckle imaging. Its mount closely resembles a radar mount and it does not employ the conventional dome. Costs for this design are projected to be considerably reduced compared to conventional designs. Results of a detailed design study will be presented. Applications to astronomy will be discussed.

  14. Earth resources technology satellite /ERTS/ data collection and transmission buoys for inland, neritic and oceanic waters

    NASA Technical Reports Server (NTRS)

    Chapman, W. S.; Yen, H. H.

    1974-01-01

    As a result of a consortium of several industries and organizations, an economical, versatile, and stable data collection and transmission buoy has been designed, developed, and deployed to gather and transmit water quality data to a ground receiving station at three-minute intervals and to the earth resources technology satellite (ERTS) as it passes over the deployed buoy every 12 hours. The buoy system, designed for both fresh and salt water application, gathers data inclusive of temperature measurement, conductivity, relative acidity, dissolved oxygen, current speed, and direction. The mechanical design philosophy used to determine and satisfy boundary conditions involving stability, ease of deployment, servicing and maintenance, minimal manufacturing costs, and fresh and salt water installation capability is discussed. The development of peripheral handling equipment and anchoring systems is described.

  15. Origin of Lα{sup x} satellite in the light rare earths on the basis of plasmon theory

    SciTech Connect

    Jain, Manjula; Shrivastava, B. D.

    2015-07-31

    The origin of most of the X-ray satellites can be explained on the basis of multiple ionization theory. However, there are several satellites which can be explained on the basis of plasmon theory. When a plasmon is excited during the X-ray emission process, one can get a low energy satellite because energy is used up in exciting the plasmon oscillations in the electron gas. A plasmon on decay can also transfer its energy to the transiting electron which subsequently fills the core vacancy giving rise to a high energy satellite. In our laboratory, a new high energy satellite Lα{sup x} has been observed in the Lα - emission spectra of the oxides of some light rare earths on the high energy side of the diagram line Lα{sub 1}. In the present paper, the origin of this high energy satellite has been explained using the theory of plasma oscillations in solids. The energy separation of the satellite from the emission line Lα{sub 1} has been calculated and then compared with the theoretical separation based on the plasmon theory. The agreement between the theoretical and experimental values is found to be good. Hence, the observed satellite can be designated as plasmon satellite.

  16. Autonomous Low Earth Orbit Satellite and Orbital Debris Tracking Using Mid Aperture COTS Optical Trackers

    NASA Astrophysics Data System (ADS)

    Ehrhorn, B.; Azari, D.

    Low Earth Orbit (LEO) and Orbital Debris tracking have become considerably important with regard to Space Situational Awareness (SSA). This paper discusses the capabilities of autonomous LEO and Orbital Debris Tracking Systems using commercially available (mid aperture 20-24 inch) telescopes, tracking gimbals, and CCD imagers. RC Optical Systems has been developing autonomous satellite trackers that allow for unattended acquisition, imaging, and orbital determination of LEOs using low cost COTS equipment. The test setup from which we are gathering data consists of an RC Optical Systems Professional Series Elevation over Azimuth Gimbal with field de-rotation, RC Optical Systems 20 inch Ritchey-Chretien Telescope coupled to an e2v CCD42-40 CCD array, and 77mm f/4 tracking lens coupled to a KAF-0402ME CCD array. Central to success of LEO acquisition and open loop tracking is accurate modeling of Gimbal and telescope misalignments and flexures. Using pro-TPoint and a simple automated mapping routine we have modeled our primary telescope to achieve pointing and tracking accuracies within a population standard deviation of 1.3 arc-sec (which is 1.1 arc-sec RMS). Once modeled, a mobile system can easily and quickly be calibrated to the sky using a simple 6-10 star map to solve for axis tilt and collimation coefficients. Acquisition of LEO satellites is accomplished through the use of a wide field imager. Using a 77mm f/4 lens and 765 x 510 x 9mu CCD array yields a 1.28 x 0.85 degree field of view in our test setup. Accurate boresite within the acquisition array is maintained throughout the full range of motion through differential tpoint modeling of the main and acquisition imagers. Satellite identification is accomplished by detecting a stationary centroid as a point source and differentiating from the background of streaked stars in a single frame. We found 100% detection rate of LEO with radar cross sections (RCS) of > 0.5 meter*meter within the acquisition array, and

  17. 40 Years Young: Social Media for the World's Longest-Running Earth-Observation Satellite Program

    NASA Astrophysics Data System (ADS)

    Riebeek, H.; Rocchio, L. E.; Taylor, M.; Owen, T.; Allen, J. E.; Keck, A.

    2012-12-01

    With social media becoming a communication juggernaut it is essential to harness the medium's power to foster better science communication. On July 23, 2012, the Landsat Earth-observing satellite program celebrated the 40th anniversary of the first Landsat launch. To more effectively communicate the impact and importance of Landsat's four-decade long data record a carefully planned social media event was designed to supplement the day's traditional media communications. The social media event, dubbed the "Landsat Social," was modeled on and supported by the NASA Social methodology. The Landsat Social was the first such event for NASA Earth science not associated with a launch. For the Landsat Social, 23 social media-savvy participants were selected to attend a joint NASA/U.S. Geological Survey Landsat anniversary press event at the Newseum in Washington, D.C. The participants subsequently toured the NASA Goddard Space Flight Facility in Greenbelt, Maryland where they had the opportunity to learn about the latest Landsat satellite; visit the Landsat mission control; download and work with Landsat data; and meet Landsat scientists and engineers. All Landsat Social participants had Twitter accounts and used the #Landsat and #NASASocial hashtags to unify their commentary throughout the day. A few key Landsat messages were communicated to the Landsat Social participants at the event's onset. Propagation of this messaging was witnessed for the duration of the Landsat Social; and a spike in online Landsat interest followed. Here, we examine the Landsat 40th anniversary social event, explain impacts made, and report lessons learned.; Landsat Social attendees are busy tweeting, texting, and blogging as Project Scientist Dr. Jim Irons talks about the Landsat Data Continuity Mission in front of the Hyperwall at NASA Goddard Space Flight Center. Photo courtesy Bill Hrybyk.

  18. A Topology Control Strategy with Reliability Assurance for Satellite Cluster Networks in Earth Observation

    PubMed Central

    Chen, Qing; Zhang, Jinxiu; Hu, Ze

    2017-01-01

    This article investigates the dynamic topology control problem of satellite cluster networks (SCNs) in Earth observation (EO) missions by applying a novel metric of stability for inter-satellite links (ISLs). The properties of the periodicity and predictability of satellites’ relative position are involved in the link cost metric which is to give a selection criterion for choosing the most reliable data routing paths. Also, a cooperative work model with reliability is proposed for the situation of emergency EO missions. Based on the link cost metric and the proposed reliability model, a reliability assurance topology control algorithm and its corresponding dynamic topology control (RAT) strategy are established to maximize the stability of data transmission in the SCNs. The SCNs scenario is tested through some numeric simulations of the topology stability of average topology lifetime and average packet loss rate. Simulation results show that the proposed reliable strategy applied in SCNs significantly improves the data transmission performance and prolongs the average topology lifetime. PMID:28241474

  19. The Effects of Solar Maximum on the Earth's Satellite Population and Space Situational Awareness

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2012-01-01

    The rapidly approaching maximum of Solar Cycle 24 will have wide-ranging effects not only on the number and distribution of resident space objects, but also on vital aspects of space situational awareness, including conjunction assessment processes. The best known consequence of high solar activity is an increase in the density of the thermosphere, which, in turn, increases drag on the vast majority of objects in low Earth orbit. The most prominent evidence of this is seen in a dramatic increase in space object reentries. Due to the massive amounts of new debris created by the fragmentations of Fengyun-1C, Cosmos 2251 and Iridium 33 during the recent period of Solar Minimum, this effect might reach epic levels. However, space surveillance systems are also affected, both directly and indirectly, historically leading to an increase in the number of lost satellites and in the routine accuracy of the calculation of their orbits. Thus, at a time when more objects are drifting through regions containing exceptionally high-value assets, such as the International Space Station and remote sensing satellites, their position uncertainties increase. In other words, as the possibility of damaging and catastrophic collisions increases, our ability to protect space systems is degraded. Potential countermeasures include adjustments to space surveillance techniques and the resetting of collision avoidance maneuver thresholds.

  20. On the computation of preliminary orbits for Earth satellites with radar observations

    NASA Astrophysics Data System (ADS)

    Gronchi, G. F.; Dimare, L.; Bracali Cioci, D.; Ma, H.

    2015-08-01

    We introduce a new method to perform preliminary orbit determination for satellites on low Earth orbits (LEO). This method works with tracks of radar observations: each track is composed by n ≥ 4 topocentric position vectors per pass of the satellite, taken at very short time intervals. We assume very accurate values for the range ρ, while the angular positions (i.e. the line of sight, given by the pointing of the antenna) are less accurate. We wish to correct the errors in the angular positions already in the computation of a preliminary orbit. With the information contained in a pair of radar tracks, using the laws of the two-body dynamics, we can write eight equations in eight unknowns. The unknowns are the components of the topocentric velocity orthogonal to the line of sight at the two mean epochs of the tracks, and the corrections Δ to be applied to the angular positions. We take advantage of the fact that the components of Δ are typically small. We show the results of some tests, performed with simulated observations, and compare this method with Gibbs' and the Keplerian integrals methods.

  1. A pseudo-magnetic flux rope observed by the THEMIS satellites in the Earth's magnetotail

    NASA Astrophysics Data System (ADS)

    Sarafopoulos, D. V.

    2011-10-01

    We investigate an extraordinary event showing all the typical magnetic flux rope (MFR) signatures, although it is not really a MFR structure. It occurred on 1 March 2008 in the Earth's magnetotail and was observed by a major tail conjunction of Time History of Events and Macroscale Interactions during Substorms (THEMIS) satellites. THEMIS B and C being located inside the central plasma sheet and almost symmetrically above and below the neutral sheet observed the same tailward retreating MFR-like structure: they indeed detected strong but oppositely directed cross-tail magnetic field excursions: positive “By core” for TH-C and negative for TH-B; an apparent inconsistency. We finally categorize the case under study as a pseudo-MFR event and we doubt that the previously studied MFR-like structures were really rope structures. We suggest that the By excursions are dictated by Ampere's law; they are produced by filamentary field-aligned currents (FACs) created in front of the “akis structure”, as it is introduced by Sarafopoulos (2008, 2010): In a locally thinned plasma sheet, the akis potentially causes charge separation due to non-adiabatic motion and stochastic scattering of ions. In turn, the newly tailward escaped ions drive field-aligned ionospheric currents in order to neutralize this region. We extensively discuss an additional and extremely rare phenomenon of “irregular MFR” cited in the literature and observed by the Cluster satellites; filamentary FACs suffice to reproduce all the observed magnetic field signatures, too.

  2. Earth's gravity field modelling based on satellite accelerations derived from onboard GPS phase measurements

    NASA Astrophysics Data System (ADS)

    Guo, X.; Ditmar, P.; Zhao, Q.; Klees, R.; Farahani, H. H.

    2017-02-01

    GPS data collected by satellite gravity missions can be used for extracting the long-wavelength part of the Earth's gravity field. We propose a new data processing method which makes use of the `average acceleration' approach to gravity field modelling. In this method, satellite accelerations are directly derived from GPS carrier phase measurements with an epoch-differenced scheme. As a result, no ambiguity solutions are needed and the systematic errors that do not change much from epoch to epoch are largely eliminated. The GPS data collected by the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) satellite mission are used to demonstrate the added value of the proposed method. An analysis of the residual accelerations shows that accelerations derived in this way are more precise, with noise being reduced by about 20 and 5% at the cross-track component and the other two components, respectively, as compared to those based on kinematic orbits. The accelerations obtained in this way allow the recovery of the gravity field to a slightly higher maximum degree compared to the solution based on kinematic orbits. Furthermore, the gravity field solution has an overall better performance. Errors in spherical harmonic coefficients are smaller, especially at low degrees. The cumulative geoid height error is reduced by about 15 and 5% up to degree 50 and 150, respectively. An analysis in the spatial domain shows that large errors along the geomagnetic equator, which are caused by a high electron density coupled with large short-term variations, are substantially reduced. Finally, the new method allows for a better observation of mass transport signals. In particular, sufficiently realistic signatures of regional mass anomalies in North America and south-west Africa are obtained.

  3. Simulation Based on Satellite System for the Application of Path Deviation of AN Asteroid Between Moon and Earth

    NASA Astrophysics Data System (ADS)

    Sathiyavel, C.

    Abstract:Asteroids are minor planets, especially those of the inner Solar System. There are also located at the stable Lagrange points of the Earth-Moon system. Most asteroids consists of carbon-rich minerals, which most meteorites are composed stony iron. The mass of near earth Asteroids as a function of its diameter is the range of densities from 1.9g/cm.3 to 3.8 g/cm.3 .For example, a 2-m diameter asteroid with a density of 1.9g/cm.3 has a mass of order 7,959 kg. If this Asteroid falls on earth then the earth will be destroyed. My proposed work is how we can avert this great danger for near feature the above mass of Asteroid. The present work is the Study of new satellite system for the application of path deviation of an Asteroid between moon and earth. The deviate angle α1 to α2 with help of Satellite system. The satellite is includes the following subsystem.1.Communication subsystem 2.Electric propulsion subsystem 3.Parasuit subsystem 4.Control system Mechanism 5.Solar power subsystem 6.Thermal control subsystem. The Simulation Based on studying of path deviation of a near earth Asteroid between Moon and Earth. The totally five Quantity of Electric propulsion techniques is used. As the satellite will gone round the earth in this initial orbit the point which is at minimum distance from the earth in that orbit(perigee) is at 255 km height and the point maximum distance in that orbit is at 25,000 km. The asteroid is passes through orbit of capture Mechanism(satellite),its after satellite system is move in the pitch up direction, due tonearest of the asteroid with help of one Quantity of Electric propulsion techniques, then theparasuite is released and the shrinks of parasuite together with of Asteroid. The path of heavy asteroid could be deviated from α1 to α2 with help of another 4 quantity of Electric propulsionTechniques.Electric propulsion thruster system is expected to become popular with the development of ion-ion pair techniques because of their

  4. Low-earth-orbit Satellite Internet Protocol Communications Concept and Design

    NASA Technical Reports Server (NTRS)

    Slywezak, Richard A.

    2004-01-01

    This report presents a design concept for a low-Earth-orbit end-to-end Internet-Protocol- (IP-) based mission. The goal is to maintain an up-to-date communications infrastructure that makes communications seamless with the protocols used in terrestrial computing. It is based on the premise that the use of IPs will permit greater interoperability while also reducing costs and providing users the ability to retrieve data directly from the satellite. However, implementing an IP-based solution also has a number of challenges, since wireless communications have different characteristics than wired communications. This report outlines the design of a low-Earth-orbit end-to-end IP-based mission; the ideas and concepts of Space Internet architectures and networks are beyond the scope of this document. The findings of this report show that an IP-based mission is plausible and would provide benefits to the user community, but the outstanding issues must be resolved before a design can be implemented.

  5. A test of general relativity using the LARES and LAGEOS satellites and a GRACE Earth gravity model: Measurement of Earth's dragging of inertial frames.

    PubMed

    Ciufolini, Ignazio; Paolozzi, Antonio; Pavlis, Erricos C; Koenig, Rolf; Ries, John; Gurzadyan, Vahe; Matzner, Richard; Penrose, Roger; Sindoni, Giampiero; Paris, Claudio; Khachatryan, Harutyun; Mirzoyan, Sergey

    We present a test of general relativity, the measurement of the Earth's dragging of inertial frames. Our result is obtained using about 3.5 years of laser-ranged observations of the LARES, LAGEOS, and LAGEOS 2 laser-ranged satellites together with the Earth gravity field model GGM05S produced by the space geodesy mission GRACE. We measure [Formula: see text], where [Formula: see text] is the Earth's dragging of inertial frames normalized to its general relativity value, 0.002 is the 1-sigma formal error and 0.05 is our preliminary estimate of systematic error mainly due to the uncertainties in the Earth gravity model GGM05S. Our result is in agreement with the prediction of general relativity.

  6. Tools and Data Services from the NASA Earth Satellite Observations for Climate Applications

    NASA Technical Reports Server (NTRS)

    Vicente, Gilberto A.

    2005-01-01

    Climate science and applications require access to vast amounts of archived high quality data, software tools and services for data manipulation and information extraction. These on the other hand require gaining detailed understanding of the data's internal structure and physical implementation to data reduction, combination and data product production. This time-consuming task must be undertaken before the core investigation can begin and is an especially difficult challenge when science objectives require users to deal with large multi-sensor data sets of different formats, structures, and resolutions. In order to address these issues the Goddard Space Flight Center (GSFC) Earth Sciences (GES), Data and Information Service Center (DISC) Distributed Active Archive Center (DAAC) has made great progress in facilitating science and applications research by developing innovative tools and data services applied to the Earth sciences atmospheric and climate data. The GES/DISC/DAAC has successfully implemented and maintained a long-term climate satellite data archive and developed tools and services to a variety of atmospheric science missions including AIRS, AVHRR, MODIS, SeaWiFS, SORCE, TOMS, TOVS, TRMM, and UARS and Aura instruments providing researchers with excellent opportunities to acquire accurate and continuous atmospheric measurements. Since the number of climate science products from these various missions is steadily increasing as a result of more sophisticated sensors and new science algorithms, the main challenge for data centers like the GES/DISC/DAAC is to guide users through the variety of data sets and products, provide tools to visualize and reduce the volume of the data and secure uninterrupted and reliable access to data and related products. This presentation will describe the effort at the GES/DISC/DAAC to build a bridge between multi-sensor data and the effective scientific use of the data, with an emphasis on the heritage satellite observations

  7. Earth Radiation Imbalance from a Constellation of 66 Iridium Satellites: Climate Science Aspects

    NASA Technical Reports Server (NTRS)

    Wiscombe, W.; Chiu, CJ. Y.

    2012-01-01

    The "global warming hiatus" since the 1998 El Nino, highlighted by Meehl et al., and the resulting "missing energy" problem highlighted by Trenberth et al., has opened the door to a more fundamental view of climate change than mere surface air temperature. That new view is based on two variables which are strongly correlated: the rate of change of ocean heat content d(OHC)/dt; and Earth Radiation Imbalance (ERI) at the top of the atmosphere, whose guesstimated range is 0.4 to 0.9 Watts per square meters (this imbalance being mainly due to increasing CO2). The Argo float array is making better and better measurements of OHC. But existing satellite systems cannot measure ERI to even one significant digit. So, climate model predictions of ERI are used in place of real measurements of it, and the satellite data are tuned to the climate model predictions. Some oceanographers say "just depend on Argo for understanding the global warming hiatus and the missing energy", but we don't think this is a good idea because d(OHC)/dt and ERI have different time scales and are never perfectly correlated. We think the ERB community needs to step up to measuring ERI correctly, just as oceanographers have deployed Argo to measure OHC correctly. This talk will overview a proposed constellation of 66 Earth radiation budget instruments, hosted on Iridium satellites, that will actually be able to measure ERI to at least one significant digit, thus enabling a crucial test of climate models. This constellation will also be able to provide ERI at two-hourly time scales and 500-km spatial scales without extrapolations from uncalibrated narrowband geostationary instruments, using the highly successful methods of GRACE to obtain spatial resolution. This high time resolution would make ERI a synoptic variable like temperature, and allow studies of ERI's response to fast-evolving phenomena like dust storms and hurricanes and even brief excursions of Total Solar Irradiance. Time permitting, we

  8. Earth Observatory Satellite system definition study. Report no. 7: EOS system definition report. Appendixes A through D

    NASA Technical Reports Server (NTRS)

    1974-01-01

    An analysis of the systems involved in the operation and support of the Earth Observatory Satellite (EOS) is presented. Among the systems considered are the following: (1) the data management system, (2) observatory to primary ground station communications links, (3) local user system, (4) techniques for recognizing ground control points, (5) the central data processing-implementation concept, and (6) program effectiveness analysis.

  9. Earth Observatory Satellite system definition study. Report no. 5: System design and specifications. Part 1: Observatory system element specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The performance, design, and quality assurance requirements for the Earth Observatory Satellite (EOS) Observatory and Ground System program elements required to perform the Land Resources Management (LRM) A-type mission are presented. The requirements for the Observatory element with the exception of the instruments specifications are contained in the first part.

  10. A Computer Program for Mapping Satellite-borne Narrow-Beam Antenna Footprints on Earth. Memorandum Number 72/3.

    ERIC Educational Resources Information Center

    Stagl, Thomas W.; Singh, Jai P.

    Written primarily to define the area of the earth covered by a narrow-beam antenna carried on a synchronous satellite in circular, near equatorial orbits, a computer program has been developed that computes the locus of intersection of a quadric cone and a sphere. The program, which outputs a list of the longitude and latitude coordinates of the…

  11. Detection, identification, and classification of mosquito larval habitats using remote sensing scanners in earth-orbiting satellites*

    PubMed Central

    Hayes, Richard O.; Maxwell, Eugene L.; Mitchell, Carl J.; Woodzick, Thomas L.

    1985-01-01

    A method of identifying mosquito larval habitats associated with fresh-water plant communities, wetlands, and other aquatic locations at Lewis and Clark Lake in the states of Nebraska and South Dakota, USA, using remote sensing imagery obtained by multispectral scanners aboard earth-orbiting satellites (Landsat 1 and 2) is described. The advantages and limitations of this method are discussed. PMID:2861917

  12. Earth Observatory Satellite system definition study. Report no. 5: System design and specifications. Part 2: Ground system element specifications

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The Ground System requirements for the Land Resources Management (LRM) type-A and type-B missions of the Earth Observatory Satellite (EOS) program are presented. Specifications for the Thematic Mapper data processing are provided (LRM A mission). The specifications also cover the R and D instruments (Thematic Mapper and High Resolution Pointable Imager) data processing for the LRM type-B mission.

  13. Hyperspectral remote sensing technology (HRST) program and the Naval EarthMap Observer (NEMO) satellite

    NASA Astrophysics Data System (ADS)

    Wilson, Thomas L.; Davis, Curtiss O.

    1998-11-01

    The Office of Naval Research (ONR) and the Naval Research Laboratory (NRL) are currently in the design phase of a program called the Hyperspectral Remote Sensing Technology (HRST) program. HRST will demonstrate the utility of a hyperspectral earth-imaging system to support Naval needs for characterization of the littoral regions of the world. One key component of the HRST program is the development of the Naval EarthMap Observer (NEMO) satellite system to provide a large hyperspectral data base. NEMO will carry the Coastal Ocean Imaging Spectrometer (COIS) which will provide images of littoral regions with 210 spectral channels over a bandpass of 0.4 to 2.5 micrometer. Since ocean environments have reflectances typically less than 5%, this system requires a very high signal-to-noise ratio (SNR). COIS will sample over a 30 km swath width with a 60 m Ground Sample Distance (GSD) with the ability to go to a 30 m GSD by utilizing the systems attitude control system to 'nod' (i.e., use ground motion compensation to slow down the ground track of the field of view). Also included in the payload is a co-registered 5m Panchromatic Imager (PIC) to provide simultaneous high spatial resolution imagery. A sun-synchronous circular orbit of 605 km allows continuous repeat coverage of the whole earth. One unique aspect of NEMO is an on board processing system, a feature extraction and data compression software package developed by NRL called the Optical Real-Time Spectral Identification System (ORASIS). ORASIS employs a parallel, adaptive hyperspectral method for real time scene characterization, data reduction, background suppression, and target recognition. The use of ORASIS is essential for management of the massive amounts of data expected from the NEMO HSI system, and for developing Naval products under HRST. The combined HSI and panchromatic images will provide critical phenomenology to aid in the operation of Naval systems in the littoral environment. The imagery can also

  14. Recovery of the Earth's gravity field from formation-flying satellites: Temporal aliasing issues

    NASA Astrophysics Data System (ADS)

    Elsaka, Basem; Kusche, Juergen; Ilk, Karl-Heinz

    2012-12-01

    Temporal and mean gravity field models derived from the twin-satellite, leader-follower mission GRACE have provided a new type of information for Earth sciences. In this contribution, we study the potential of various alternative satellite formations for gravity field determination in the post-GRACE era in a simulation environment. In particular, the effects of spherical harmonic truncation and of temporal aliasing in the processing of gravity products from such future formations are investigated. Temporal aliasing is studied based on simulated observations of satellite formation flight (SFF) configurations and simulated errors in short-term background models for the non-tidal atmosphere, ocean masses and the continental water storage. We study the potential improvement of SFF gravity field solutions in terms of spherical harmonics truncation of up to degree/order 100. Furthermore, we simulate the recovery of the hydrological signal from various SFF configurations with and without the contamination of the aliasing errors, which were derived from model differences. We implement full-scale simulations for all scenarios to assess the quality of future gravity products in the form of spherical harmonic models. To this end, we create simulated measurements for four satellite configurations (known as pendulum, the radial Cartwheel, the LISA and the pendulum-3S) besides the GRACE-type configuration as a reference. All simulations are restricted to a time span of one month to limit computation costs. As expected, the gravity field products derived from future SFF configurations may surpass those obtained from GRACE in terms of isotropy of the gravity field. Our study provides detailed results for many scenarios ranging in terms of spherical harmonic truncation to up to 100 for mean and temporal solutions. Furthermore, we show that specific SFF configurations involving radial and cross-track information strengthen the recovery of the gravitational signal; in addition they

  15. News of Brazilian space activities. [use of satellite data in meteorology and Earth resources programs

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Remote sensing and meteorological observations of satellites are covered. Development of an oceanographic atlas, prediction of droughts, and results of geological surveys using satellite data are discussed.

  16. The Change Indices of Solar and Geomagnetic Activity and Their Influence on the Dynamics of Drag of Artificial Satellite

    NASA Astrophysics Data System (ADS)

    Komendant, V. H.; Koshkin, N. I.; Ryabov, M. I.; Sukharev, A. L.

    2016-12-01

    The time-frequency and multiple regression analysis of the orbital parameter characterizing the drag of satellites on circular and elliptical orbits with different perigees and orbital inclinations in the atmosphere of the Earth was being conducted in 23-24 cycles of solar activity. Among the factors influencing braking dynamics of satellites were taken: W - Wolf numbers; Sp - the total area of sunspot groups of the northern and southern hemispheres of the Sun, F10.7 - the solar radio flux at 10,7 cm; E - electron flux with energies more than 0,6 MeV è 2 MeV; planetary, high latitude and middle latitude geomagnetic index Ap. In the atmospheric drag dynamics of satellites, the following periods were detected: 6-year, 2.1-year, annual, semi-annual, 27-days, 13- and 11-days. Similar periods are identified in indexes of solar and geomagnetic activity. Dependence of the periods of satellites motion on extremes of solar activities and space weather conditions was conducted.

  17. 1999-2003 Shortwave Characterizations of Earth Radiation Budget Satellite (ERBS)/Earth Radiation Budget Experiment (ERBE) Broadband Active Cavity Radiometer Sensors

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Smith, George L.; Wong, Takmeng

    2008-01-01

    From October 1984 through May 2005, the NASA Earth Radiation Budget Satellite (ERBS/ )/Earth Radiation Budget Experiment (ERBE)ERBE nonscanning active cavity radiometers (ACR) were used to monitor long-term changes in the earth radiation budget components of the incoming total solar irradiance (TSI), earth-reflected TSI, and earth-emitted outgoing longwave radiation (OLR). From September1984 through September 1999, using on-board calibration systems, the ERBS/ERBE ACR sensor response changes, in gains and offsets, were determined from on-orbit calibration sources and from direct observations of the incoming TSI through calibration solar ports at measurement precision levels approaching 0.5 W/sq m , at satellite altitudes. On October 6, 1999, the onboard radiometer calibration system elevation drive failed. Thereafter, special spacecraft maneuvers were performed to observe cold space and the sun in order to define the post-September 1999 geometry of the radiometer measurements, and to determine the October 1999-September 2003 ERBS sensor response changes. Analyses of these special solar and cold space observations indicate that the radiometers were pointing approximately 16 degrees away from the spacecraft nadir and on the anti-solar side of the spacecraft. The special observations indicated that the radiometers responses were stable at precision levels approaching 0.5 W/sq m . In this paper, the measurement geometry determinations and the determinations of the radiometers gain and offset are presented, which will permit the accurate processing of the October 1999 through September 2003 ERBE data products at satellite and top-of-the-atmosphere altitudes.

  18. Tracking Low Earth Orbit Small Debris with GPS Satellites as Bistatic Radar

    NASA Astrophysics Data System (ADS)

    Mahmud, M.; Qaisar, S.; Benson, C.

    2016-09-01

    Space debris is a growing problem and collisions are potentially lethal to satellites. Trajectories for small objects are predicted based on infrequent measurements, and the scale and therefore cost of maneuver required to avoid collisions is a function of trajectory accuracy. Frequent and precise observations will improve trajectory accuracy. In this paper, we extend on aspects of the feasibility of tracking space debris in Low Earth Orbit using emissions from GNSS satellites as bistatic radar illuminators. The wavelengths of GNSS signals are of order 20 cm and our primary focus is to track debris smaller than this, thereby maintaining phase stability of the scattered signals, enabling very long coherent processing intervals. However, the signals scattered by debris will be very weak at a terrestrial receiver, requiring the computationally expensive integration of a large number of signals, over an extended duration and with a large phased array. Detection of such weak signals in the presence of relatively strong direct-arrival signals requires extremely high cross-correlation protection. We show that sufficient cross-correlation protection can be obtained due to the large and varying Doppler shift, and also illustrate a novel processing approach utilizing downshifting of the collected signal to audio frequency. This technique dramatically reduces the cost and complexity of updating debris trajectories. The processing cost of preserving an uncertainty volume of many hundreds of meters around the predicted debris track is very modest, and searching within that uncertainty volume is undertaken at audio sampling rates. Moreover, we explore techniques that further lower the already modest cost of the non-linear search within the preserved uncertainty volume. We conclude with an outline of a system using these techniques that could provide centimetre level tracking of large quantities of small orbital objects at a modest cost.

  19. Interference on the deep space Earth station systems from EESS satellites operating at the 8025-8400 MHz band

    NASA Astrophysics Data System (ADS)

    Hu, Shengbo; Meng, Xin

    2007-11-01

    According to the ITU Radio Regulations and CCSDS Recommendation about radio frequency, the 8400-8450 MHz band is allocated for Space Research Service (SRS) (category B) space-to-earth, and the 8400-8450 MHz deep space band is critical to the success of deep space missions. Since the 8025-8400MHz Earth Exploration Satellite Service (EESS) band is allocated for the downlinks of earth exploration satellites, the unwanted adjacent band emission may exceed the protection criterion established by the ITU-R for the protection of the deep space earth stations by a large amount and results in harmful interference to the deep space earth station systems. This paper first introduces a conceptual future scenario with frequency bands. Secondly, the paper discusses the characteristics that are unique to the deep space downlinks and then presents the characteristics of the EESS out-of-band interference to the deep space downlink X-band. Finally, the paper describes the effects of the interference on the deep space earth station systems.

  20. Assessing change in the earth's land surface albedo with moderate resolution satellite imagery

    NASA Astrophysics Data System (ADS)

    Sun, Qingsong

    Land surface albedo describes the proportion of incident solar radiant flux that is reflected from the Earth's surface and therefore is a crucial parameter in modeling and monitoring attempts to capture the current climate, hydrological, and biogeochemical cycles and predict future scenarios. Due to the temporal variability and spatial heterogeneity of land surface albedo, remote sensing offers the only realistic method of monitoring albedo on a global scale. While the distribution of bright, highly reflective surfaces (clouds, snow, deserts) govern the vast majority of the fluctuation, variations in the intrinsic surface albedo due to natural and human disturbances such as urban development, fire, pests, harvesting, grazing, flooding, and erosion, as well as the natural seasonal rhythm of vegetation phenology, play a significant role as well. The development of times series of global snow-free and cloud-free albedo from remotely sensed observations over the past decade and a half offers a unique opportunity to monitor and assess the impact of these alterations to the Earth's land surface. By utilizing multiple satellite records from the MODerate-resolution Imaging Spectroradiometer (MODIS), the Multi-angle Imaging Spectroradiometer (MISR) and the Visible Infrared Imaging Radiometer Suite (VIIRS) instruments, and developing innovative spectral conversion coefficients and temporal gap-filling strategies, it has been possible to utilize the strengths of the various sensors to improve the spatial and temporal coverage of global land surface albedo retrievals. The availability of these products is particularly important in tropical regions where cloud cover obscures the forest for significant periods. In the Amazon, field ecologists have noted that some areas of the forest ecosystem respond rapidly with foliage growth at the beginning of the dry season, when sunlight can finally penetrate fully to the surface and have suggested this phenomenon can continue until

  1. Space in environmental diplomacy: Exploring the role of earth observing satellites for monitoring international environmental agreements

    NASA Astrophysics Data System (ADS)

    Johnston, Shaida Sahami

    This research determines under what conditions, and for what types of environmental treaties, Earth observation (EO) is useful for monitoring international environmental agreements. The research extracts specific monitoring requirements from nine multilateral environmental agreements (MEAs) and explores how satellite EO data can be used to support them. The technical characteristics of the sensor systems and science data products associated with current and planned EO satellites were analyzed and mapped to the MEA requirements, providing a significant step toward linking the EO community with the international treaty community implementing these environmental agreements. The research results include a listing and analysis of the positive and negative factors that influence whether EO data are useful for monitoring and verifying MEAs, analysis of existing international EO institutions, and a set of key findings describing the conditions under which EO data are most useful to the treaties. The use of EO data in various treaty phases is also analyzed, drawing the conclusion that EO data are most useful for monitoring and treaty refinement and not very useful for compliance verification or enforcement. MEAs manage compliance using governance structures that offer expertise and resources to assist states that are reported to be in non-compliance, rather than enforce compliance with sanctions or other punishments. In addition, the temporal and spatial resolution of the current and planned fleet of satellites does not provide the required detail needed for MEA verification. Identifying specific treaty implementation deficiencies requires additional information that cannot be gathered from EO data; on-site economic, social, and environmental conditions are critical elements in assessing compliance verification. But for environmental monitoring and assessments, MEA effectiveness reviews, and national reporting required for each MEA, EO data are very useful. They provide

  2. Istoriya issledovanij kosmicheskogo prostranstva. Chast' II. Estestvennaya i iskusstvennaya radiatsiya v magnitosfere Zemli %t History of space researches. Part 2. Natural and artificial radiation in the Earth magnetosphere

    NASA Astrophysics Data System (ADS)

    Temnyj, V. V.

    The discussion about the structure and source of the intense radiation zone detected onboard the first satellites begun in 1958 and was finished in 1961. It was found that this zone is not a unitary reservoir of auroral electrons. Its remote part called the "outer radiation belt" indeed if filled with electrons, but their energies far exceed the auroral energy range. The near-Earth area of the radiation zone consisting of protons with energies Ep ~ 100 MeV was called the "inner radiation belt". Intense energy fluxes of electrons were also detected in this zone. Particles of the radiation belts are trapped in the geomagnetic field. They rotate around and bounce along the field lines and also drift around of the Earth. The drift existence was proved by the formation of narrow artificial radiation belts over the whole globe after high-altitude by the "ARGUS" nuclear explosions on September 1958. They were used as markers for creation of two-dimensional geomagnetic coordinate system (L,B) applied to define the distributions of trapped particles. Until 1960, the electron fluxes of the outer radiation belt were assumed to be a possible source of auroras. However, the subsequent experiments have lowered the level of these fluxes by orders of magnitude, and these data argued against this assumption. The geomagnetic field depressions detected in 1959 were referred to an effect of the ring current, which began to be registered in 1961-1964 as fluxes of trapped protons with energies Ep ~ 100 keV. Their energy density was not less than 10% of the magnetic-energy local density B2/8π, and constant diamagnetic field depression by its was not less than 15%. The "STARFISH" high-altitude thermonuclear explosion on July 9, 1962 unexpectedly has resulted in the formation of an artificial radiation belt filled with electrons. It has polluted the Earth's central magnetosphere for many years. Nevertheless, the experiment made it possible to obtain the distribution of electrons of a

  3. Land and Ocean Surface Skin Temperature from Geostationary and Low Earth Orbit Satellite Observations

    NASA Astrophysics Data System (ADS)

    Scarino, B. R.; Minnis, P.; Palikonda, R.; Heck, P.; Bedka, K.

    2013-12-01

    Observations from imagers aboard Geostationary Earth Orbit (GEO) and Low Earth Orbit (LEO) satellites allow for spatially detailed, near-real-time retrievals of cloud and surface radiation properties. Validating and improving the quality of these observations is important for the advancement of climate studies. Compared to GEO sensors, LEO-based instruments can typically provide higher-spatial-resolution datasets, but at the cost of limited areal coverage and reduced sampling frequency at any given location. Conversely, the persistence and coverage of GEO-based imagers offer the opportunity for more frequent retrievals of near-instantaneous, near-global surface properties. Among other cloud and clear-sky retrieval parameters, NASA Langley provides pixel-level land and ocean skin temperature datasets by comparing clear-pixel top-of-atmosphere infrared temperature observations with modeled, atmospheric-absorption-corrected surface temperature values. Depending on cloud-cover thresholds, this method yields surface temperature values that are within 0.5 to 2.0 K of measurements from ground-based networks including the Southern Great Plains Atmospheric Radiation Measurement Climate Research Facility, the U.S. Climate Reference Network, and the global Baseline Surface Radiation Network. Furthermore, monthly mean sea surface temperatures (SSTs) are within 0.5 to 2.0 K of NOAA-based SST climatology records, and have an uncertainty of less than 1 K. These data will be useful for assimilation into atmospheric models, which offer improved performance when high-accuracy, high-resolution initial radiometric and surface conditions are included. Modelers should find the immediate availability and broad coverage of these skin temperature observations valuable, which can lead to improved forecasting and more advanced global climate models.

  4. THEMIS satellite observations of hot flow anomalies at Earth's bow shock

    NASA Astrophysics Data System (ADS)

    Chu, Christina; Zhang, Hui; Sibeck, David; Otto, Antonius; Zong, QiuGang; Omidi, Nick; McFadden, James P.; Fruehauff, Dennis; Angelopoulos, Vassilis

    2017-03-01

    Hot flow anomalies (HFAs) at Earth's bow shock were identified in Time History of Events and Macroscale Interactions During Substorms (THEMIS) satellite data from 2007 to 2009. The events were classified as young or mature and also as regular or spontaneous hot flow anomalies (SHFAs). The dataset has 17 young SHFAs, 49 mature SHFAs, 15 young HFAs, and 55 mature HFAs. They span a wide range of magnetic local times (MLTs) from approximately 7 to 16.5 MLT. The largest ratio of solar wind to HFA core density occurred near dusk and at larger distances from the bow shock. In this study, HFAs and SHFAs were observed up to 6.3 RE and 6.1 RE (Earth radii), respectively, upstream from the model bow shock. HFA-SHFA occurrence decreases with distance upstream from the bow shock. HFAs of the highest event core ion temperatures were not seen at the flanks. The ratio of HFA ion temperature increase to HFA electron temperature increase is highest around 12 MLT and slightly duskward. For SHFAs, (Tihfa/Tisw)/(Tehfa/Tesw) generally increased with distance from the bow shock. Both mature and young HFAs are more prevalent when there is an approximately radial interplanetary magnetic field. HFAs occur most preferentially for solar wind speeds from 550 to 600 km s-1. The correlation coefficient between the HFA increase in thermal energy density from solar wind values and the decrease in kinetic energy density from solar wind values is 0.62. SHFAs and HFAs do not show major differences in this study.

  5. Pointing losses in single-axis and fixed-mount earth-station antennas due to satellite movement

    NASA Astrophysics Data System (ADS)

    Buchsbaum, L. M.

    1986-06-01

    There are substantial cost advantages in the use of single-axis or fixed-mount earth-station antennas, thus reducing or eliminating the need for autotracking in earth-stations operating with quasi-stationary satellites. Such cost advantages are more relevant in small antennas where the tracking system represents a larger percentage of the overall cost. In addition, small antennas are particularly suitable to be operated without autotracking, owing to their wider half-power beamwidth. This paper describes a model for calculating the antenna pointing loss as a function of the antenna diameter, operating frequency band, satellite station-keeping tolerances, and the relative geometry between the earth-station and the satellite. The model has been extensively used in the development of Intelsat's IBS and VISTA services as well as in domestic leases. Although the model has been developed based on orbital mechanics equations, its emphasis is towards earth-station and systems engineering applications. Some example calculations and results obtained through an HP-41 CV programmable calculator are also provided.

  6. Results of 17 Independent Geopositional Accuracy Assessments of Earth Satellite Corporation's GeoCover Landsat Thematic Mapper Imagery. Geopositional Accuracy Validation of Orthorectified Landsat TM Imagery: Northeast Asia

    NASA Technical Reports Server (NTRS)

    Smith, Charles M.

    2003-01-01

    This report provides results of an independent assessment of the geopositional accuracy of the Earth Satellite (EarthSat) Corporation's GeoCover, Orthorectified Landsat Thematic Mapper (TM) imagery over Northeast Asia. This imagery was purchased through NASA's Earth Science Enterprise (ESE) Scientific Data Purchase (SDP) program.

  7. Using NASA's Giovanni Web Portal to Access and Visualize Satellite-Based Earth Science Data in the Classroom

    NASA Astrophysics Data System (ADS)

    Lloyd, S. A.; Acker, J. G.; Prados, A. I.; Leptoukh, G. G.

    2008-12-01

    One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite- based remote sensing datasets in a format that is accessible and optimal for their data analysis needs. At the Goddard Earth Sciences Data and Information Services Center (GES-DISC) alone, on the order of hundreds of Terabytes of data are available for distribution to scientists, students and the general public. The single biggest and time-consuming hurdle for most students when they begin their study of the various datasets is how to slog through this mountain of data to arrive at a properly sub-setted and manageable dataset to answer their science question(s). The GES DISC provides a number of tools for data access and visualization, including the Google-like Mirador search engine and the powerful GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) web interface. Giovanni provides a simple way to visualize, analyze and access vast amounts of satellite-based Earth science data. Giovanni's features and practical examples of its use will be demonstrated, with an emphasis on how satellite remote sensing can help students understand recent events in the atmosphere and biosphere. Giovanni is actually a series of sixteen similar web-based data interfaces, each of which covers a single satellite dataset (such as TRMM, TOMS, OMI, AIRS, MLS, HALOE, etc.) or a group of related datasets (such as MODIS and MISR for aerosols, SeaWIFS and MODIS for ocean color, and the suite of A-Train observations co-located along the CloudSat orbital path). Recently, ground-based datasets have been included in Giovanni, including the Northern Eurasian Earth Science Partnership Initiative (NEESPI), and EPA fine particulate matter (PM2.5) for air quality. Model data such as the Goddard GOCART model and MERRA meteorological reanalyses (in process) are being increasingly incorporated into Giovanni to facilitate model- data intercomparison. A full suite of data

  8. Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 5: Specification for EROS operations control center

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The functional, performance, and design requirements for the Operations Control Center (OCC) of the Earth Observatory Satellite (EOS) system are presented. The OCC controls the operations of the EOS satellite to acquire mission data consisting of: (1) thematic mapper data, (2) multispectral scanner data on EOS-A, or High Resolution Pointable Imager data on EOS-B, and (3) data collection system (DCS) data. The various inputs to the OCC are identified. The functional requirements of the OCC are defined. The specific systems and subsystems of the OCC are described and block diagrams are provided.

  9. Evolving earth-based and in-situ satellite network architectures for Mars communications and navigation support

    NASA Technical Reports Server (NTRS)

    Hastrup, Rolf; Weinberg, Aaron; Mcomber, Robert

    1991-01-01

    Results of on-going studies to develop navigation/telecommunications network concepts to support future robotic and human missions to Mars are presented. The performance and connectivity improvements provided by the relay network will permit use of simpler, lower performance, and less costly telecom subsystems for the in-situ mission exploration elements. Orbiting relay satellites can serve as effective navigation aids by supporting earth-based tracking as well as providing Mars-centered radiometric data for mission elements approaching, in orbit, or on the surface of Mars. The relay satellite orbits may be selected to optimize navigation aid support and communication coverage for specific mission sets.

  10. Evolving earth-based and in-situ satellite network architectures for Mars communications and navigation support

    NASA Astrophysics Data System (ADS)

    Hastrup, Rolf; Weinberg, Aaron; McOmber, Robert

    1991-09-01

    Results of on-going studies to develop navigation/telecommunications network concepts to support future robotic and human missions to Mars are presented. The performance and connectivity improvements provided by the relay network will permit use of simpler, lower performance, and less costly telecom subsystems for the in-situ mission exploration elements. Orbiting relay satellites can serve as effective navigation aids by supporting earth-based tracking as well as providing Mars-centered radiometric data for mission elements approaching, in orbit, or on the surface of Mars. The relay satellite orbits may be selected to optimize navigation aid support and communication coverage for specific mission sets.

  11. Low-tech highly efficient radiotechnical solutions for meteors and satellite observations

    NASA Astrophysics Data System (ADS)

    Vovk, V. S.; Shulga, O. V.; Sybiryakova, Ye. S.; Kaliuzny, M. P.; Bushuev, F. I.; Kulichenko, M. O.

    2017-02-01

    Single-station technique of meteors' observation using inexpensive receivers is developed. The receivers are also suitable for observing active artificial Earth's satellites on solar-synchronous orbits when measuring the Doppler shift frequency at which they emit.

  12. Massive photometry of low-altitude artificial satellites on Mini-Mega-TORTORA

    NASA Astrophysics Data System (ADS)

    Karpov, S.; Katkova, E.; Beskin, G.; Biryukov, A.; Bondar, S.; Davydov, E.; Ivanov, E.; Perkov, A.; Sasyuk, V.

    2016-12-01

    The nine-channel Mini-Mega-TORTORA (MMT-9) optical wide-field monitoring system with high temporal resolution system is in operation since June 2014. The system has 0.1 s temporal resolution and effective detection limit around 10 mag (calibrated to V filter) for fast-moving objects on this timescale. In addition to its primary scientific operation, the system detects 200-500 tracks of satellites every night, both on low-altitude and high ellipticity orbits. Using these data we created and support the public database of photometric characteristics for these satellites, available online.

  13. MLRS - A lunar/artificial satellite laser ranging facility at the McDonald Observatory

    NASA Technical Reports Server (NTRS)

    Shelus, P. J.

    1985-01-01

    Experience from lunar and satellite laser ranging experiments carried out at McDonald Observatory has been used to design the McDonald Laser Ranging Station (MLRS). The MLRS is a dual-purpose installation designed to obtain observations from the LAGEOS satellite and lunar targets. The instruments used at the station include a telescope assembly 0.76 meters in diameter; a Q-switched doubled neodymium YAG laser with a pulse rate of three nanoseconds; and a GaAs photodetector with Fabry-Perot interferometric filter. A functional diagram of the system is provided. The operating parameters of the instruments are summarized in a table.

  14. Earth Resources Technology Satellite: Non-US standard catalog No. N-13

    NASA Technical Reports Server (NTRS)

    1973-01-01

    To provide dissemination of information regarding the availability of Earth Resources Technology Satellite (ERTS) imagery, a Non-U.S. Standard Catalog is published on a monthly schedule. The catalogs identify imagery which has been processed and input to the data files during the preceding month. The Non-U.S. Standard Catalog includes imagery covering all areas except that of the United States, Hawaii, and Alaska. Imagery adjacent to the Continental U.S. and Alaska borders will normally appear in the U.S. Standard Catalog. As a supplement to these catalogs, an inventory of ERTS imagery on 16 millimeter microfilm is available. The catalogs consist of four parts: (1) annotated maps which graphically depict the geographic areas covered by the imagery listed in the current catalog, (2) a computer-generated listing organized by observation identification number (ID) with pertinent information for each image, (3) a computer listing of observations organized by longitude and latitude, and (4) observations which have had changes made in their catalog information since the original entry in the data base.

  15. The Earth Observing System Microwave Limb Sounder (EOS MLS) on the Aura Satellite

    NASA Technical Reports Server (NTRS)

    Waters, Joe W.; Froidevaux, Lucien; Harwood, Robert S.; Jarnot, Robert F.; Pickett, Herbert M.; Read, William G.; Siegel, Peter H.; Cofield, Richard E.; Filipiak, Mark J.; Flower, Dennis A.; Holden, James R.; Lau, Gary K.; Livesey, Nathaniel J.; Manney, Gloria L; Pumphrey, Hugh C.; Santee, Michelle L.; Wu, Dong L.; Cuddy, David T.; Lay, Richard R.; Loo, Mario S.; Perun, Vincent S.; Schwartz, Michael J.; Stek, Paul C.; Thurstans, Robert P.; Boyles, Mark A.

    2006-01-01

    The Earth Observing System Microwave Limb Sounder measures several atmospheric chemical species (OH, HO2, H2O, O3, HCl, ClO, HOCl, BrO, HNO3, N2O, CO, HCN, CH3CN, volcanic SO2), cloud ice, temperature, and geopotential height to improve our understanding of stratospheric ozone chemistry, the interaction of composition and climate, and pollution in the upper troposphere. All measurements are made simultaneously and continuously, during both day and night. The instrument uses heterodyne radiometers that observe thermal emission from the atmospheric limb in broad spectral regions centered near 118, 190, 240, and 640 GHz, and 2.5 THz. It was launched July 15, 2004 on the National Aeronautics and Space Administration's Aura satellite and started full-up science operations on August 13, 2004. An atmospheric limb scan and radiometric calibration for all bands are performed routinely every 25 s. Vertical profiles are retrieved every 165 km along the suborbital track, covering 82 S to 82 N latitudes on each orbit. Instrument performance to date has been excellent; data have been made publicly available; and initial science results have been obtained.

  16. A third-order theory for the effect of drag on earth satellite orbits

    NASA Astrophysics Data System (ADS)

    Sharma, Ram K.

    1992-09-01

    Analytical theory for the motion of near-earth satellite orbits with the air drag effect is developed in terms of the KS elements, utilizing an analytical oblate exponential atmospheric model. The series expansions include up to cubic terms in e (eccentricity) and c(a small parameter dependent on the flattening of the atmosphere). Due to the symmetry of the KS element equations, only one of the eight equations is integrated analytically to obtain the state vector at the end of each revolution. Numerical comparisons are made with nine test cases, selected to cover a wide range of eccentricity with perigee heights near to 300 km at three different inclinations. A comparison of three orbital parameters: semi-major axis, eccentricity and argument of perigee, perturbed by air drag with oblate atmosphere is made with the previously developed second-order theory. It is found that with the present theory with increase in eccentricity there is improvement in semi-major axis and eccentricity computations over the second-order theory.

  17. Measurements of the earth radiation budget from satellites during the first GARP global experiment

    NASA Technical Reports Server (NTRS)

    Vonder Haar, T. H.; Campbell, G. G.; Smith, E. A.; Arking, A.; Coulson, K.; Hickey, J.; House, F.; Ingersoll, A.; Jacobowitz, H.; Smith, L.

    1981-01-01

    Radiation budget data (which will aid in climate model development) and solar constant measurements (both to be used for the study of long term climate change and interannual seasonal weather variability) are presented, obtained during Nimbus-6 and Nimbus-7 satellite flights, using wide-field-of-view, scanner, and black cavity detectors. Data on the solar constant, described as a function of the date of measurement, are given. The unweighed mean amounts to 1377 + or - 20 per sq Wm, with a standard deviation of 8 per sq Wm. The new solar data are combined with earlier measurements, and it is suggested that the total absolute energy output of the sun is a minimum at 'solar maximum' and vice versa. Attention is given to the measurements of the net radiation budget, the planetary albedo, and the infrared radiant exitance. The annual and semiannual cycles of normal variability explain most of the variance of energy exchange between the earth and space. Examination of separate ocean and atmospheric energy budgets implies a net continent-ocean region energy exchange.

  18. Comparison and testing of extended Kalman filters for attitude estimation of the Earth radiation budget satellite

    NASA Technical Reports Server (NTRS)

    Deutschmann, Julie; Bar-Itzhack, Itzhack Y.; Rokni, Mohammad

    1990-01-01

    The testing and comparison of two Extended Kalman Filters (EKFs) developed for the Earth Radiation Budget Satellite (ERBS) is described. One EKF updates the attitude quaternion using a four component additive error quaternion. This technique is compared to that of a second EKF, which uses a multiplicative error quaternion. A brief development of the multiplicative algorithm is included. The mathematical development of the additive EKF was presented in the 1989 Flight Mechanics/Estimation Theory Symposium along with some preliminary testing results using real spacecraft data. A summary of the additive EKF algorithm is included. The convergence properties, singularity problems, and normalization techniques of the two filters are addressed. Both filters are also compared to those from the ERBS operational ground support software, which uses a batch differential correction algorithm to estimate attitude and gyro biases. Sensitivity studies are performed on the estimation of sensor calibration states. The potential application of the EKF for real time and non-real time ground attitude determination and sensor calibration for future missions such as the Gamma Ray Observatory (GRO) and the Small Explorer Mission (SMEX) is also presented.

  19. Larmor electric field observed at the Earth's magnetopause by Polar satellite

    SciTech Connect

    Koga, D. Gonzalez, W. D.; Silveira, M. V. D.; Mozer, F. S.; Cardoso, F. R.

    2014-10-15

    We present, for the first time, observational evidence of a kinetic electric field near the X-line associated with asymmetric reconnection at the Earth's dayside magnetopause using Polar observations. On March 29, 2003, Polar satellite detected an asymmetric collisionless reconnection event. This event shows a unipolar Hall electric field signature and a simple deviation from the guide field during the magnetopause crossing, with the absence of an ion plasma jet outflow indicating that the magnetopause crossing was near the X-line. As expected from particle-in-cell simulations by Malakit et al. (Phys. Rev. Lett. 111, 135001 (2013)), an earthward pointing normal electric field appears in the magnetospheric side of the ion diffusion region. The electric field satisfies two necessary conditions for the existence of the finite ion Larmor radius effect: (1) the ion Larmor radius (r{sub g2}) is larger than the distance between the stagnation point and the edge of the ion diffusion region in the strong magnetic field side (δ{sub S2}) and (2) the spatial extent of the kinetic electric field (δ{sub EL}) is of the order of the ion Larmor radius. Furthermore, it is shown that the peak value of the Larmor electric field is comparable to the predicted value. The observation of the Larmor electric field can be valuable in other analyses to show that the crossing occurred near the X-line.

  20. Formation Flying Satellite Control Around the L2 Sun-Earth Libration Point

    NASA Astrophysics Data System (ADS)

    Hamilton, Nicholas H.

    2001-12-01

    A growing interest in formation flying satellites demands development and analysis of control and estimation algorithms for station-keeping and formation maneuvering. This thesis discusses the development of a discrete linear-quadratic- regulator control algorithm for formations in the vicinity of the L2 sun-earth libration point. The development of an appropriate Kalman filter is included as well. Simulations are created for the analysis of the station-keeping and various formation maneuvers of the Stellar Imager mission. The simulations provide tracking error, estimation error, and control effort results. From the control effort, useful design parameters such as AV and propellant mass are determined. For formation maneuvering, the drone spacecraft track to within 4 meters of their desired position and within 1.3 millimeters per second of their desired zero velocity. The filter, with few exceptions, keeps the estimation errors within their three-sigma values. Without noise, the controller performs extremely well, with the drones tracking to within several micrometers. Bach drone uses around 1 to 2 grams of propellant per maneuver, depending on the circumstances.