Science.gov

Sample records for satellites

  1. 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.

  2. Satellite Communication.

    ERIC Educational Resources Information Center

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  3. Satellite communications

    NASA Astrophysics Data System (ADS)

    Rubin, Philip A.

    A review of the economic and technological status of the satellite communications industry is presented. The history of satellite communications is outlined, focusing on the launching of Syncom III in 1963. The basic operation of communication satellites is explained. The differences between C and Ku frequency bands are examined. Economic issues related to satellite communications are discussed in detail.

  4. Satellite communications

    NASA Astrophysics Data System (ADS)

    Saha, M. K.

    1982-11-01

    The paper describes the basic principles and the historial development of satellite communications. Various satellite systems for global communications are discused and compared. Some typical operational communication satellite systems summary including geostationary systems are presented. Considerations leading to the system design including the link design for various multiple access techniques and the future trends in satellite communications systems are also discussed.

  5. Satellite RNAs and Satellite Viruses.

    PubMed

    Palukaitis, Peter

    2016-03-01

    Satellite RNAs and satellite viruses are extraviral components that can affect either the pathogenicity, the accumulation, or both of their associated viruses while themselves being dependent on the associated viruses as helper viruses for their infection. Most of these satellite RNAs are noncoding RNAs, and in many cases, have been shown to alter the interaction of their helper viruses with their hosts. In only a few cases have the functions of these satellite RNAs in such interactions been studied in detail. In particular, work on the satellite RNAs of Cucumber mosaic virus and Turnip crinkle virus have provided novel insights into RNAs functioning as noncoding RNAs. These effects are described and potential roles for satellite RNAs in the processes involved in symptom intensification or attenuation are discussed. In most cases, models describing these roles involve some aspect of RNA silencing or its suppression, either directly or indirectly involving the particular satellite RNA. PMID:26551994

  6. Satellite Videoconferences

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA is helping thousands of teachers to learn more about aerospace matters, improve their classroom skills, and expand significantly the content of their aerospace education curricula by means of live educational satellite videoconferences. The 1 1/2 hour 'Update for Teachers' programs originate at Oklahoma State University (OSU) Telecommunications Center. The television signals are transmitted to the WESTAR IV communications satellite, which remits them to participating schools across the U.S. and in parts of Mexico and Canada. The schools are equipped with small home style satellite reception dishes. Education Satellite Videoconference programs are conducted four times yearly, covering a variety of aerospace subjects. Teachers can call toll-free and have questions answered after the speaker's presentations. Information about NASA educational resources and how to obtain them will be provided.

  7. Satellite observations

    NASA Astrophysics Data System (ADS)

    1984-05-01

    In 1982 and 1983, six scientific satellites were operated successfully. Two of them, JIKIKEN and ISS-b, performed observations of the Earth's plasma environment. HINOTORI, the solar maximum satellite, observed a number of solar flares. HAKUCHO and newly launched TENMA conducted various observations of cosmic X-ray sources. HIMAWARI-2 is a meteorological satellite but its payload includes a solar particle monitor. EXOS-C was successfully launched in February, 1983, and participants in the MAP (Middle Atmosphere Program). Following these missions, the PLANET-A project comprising two missions, MS-T5 and PLANET-A, is under preparation for the participation in the international cooperative exploration of Comet P/Halley. The third X-ray astronomy satellite ASTRO-C is currently scheduled for 1987 launch.

  8. Satellite myths

    NASA Astrophysics Data System (ADS)

    Easton, Roger L.; Hall, David

    2008-01-01

    Richard Corfield's article “Sputnik's legacy” (October 2007 pp23-27) states that the satellite on board the US Vanguard rocket, which exploded during launch on 6 December 1957 two months after Sputnik's successful take-off, was “a hastily put together contraption of wires and circuitry designed only to send a radio signal back to Earth”. In fact, the Vanguard satellite was developed over a period of several years and put together carefully using the best techniques and equipment available at the time - such as transistors from Bell Laboratories/Western Electric. The satellite contained not one but two transmitters, in which the crystal-controlled oscillators had been designed to measure both the temperature of the satellite shell and of the internal package.

  9. Small satellites

    NASA Technical Reports Server (NTRS)

    Thomas, P.; Veverka, J.; Dermott, S.

    1986-01-01

    Satellites smaller than Mimas (r = 195 km) are distinguished by irregular overall shapes and by rough limb topography. Material properties and impact cratering dominate the shaping of these objects. Long fragmentation histories can produce a variety of internal structures, but so far there is no direct evidence that any small satellite is an equilibrium ellipsoid made up of noncohesive gravitationally bound rubble. One many bodies that orbit close to their primary the tidal and rotational components of surface gravity strongly affect the directions of local g and thereby affect the redistribution of regolith by mass wasting. Downslope movement of regolith is extensive on Deimos, and is probably effective on many other small satellites. It is shown that in some cases observed patterns of downslope mass wasting cold produce useful constraints on the satellite's mean density. The diversity of features seen in the few high-resolution images of small satellites currently available suggests that these objects have undergone complex histories of cratering, fragmentation, and regolith evolution.

  10. Centriolar Satellites

    PubMed Central

    Kubo, Akiharu; Sasaki, Hiroyuki; Yuba-Kubo, Akiko; Tsukita, Shoichiro; Shiina, Nobuyuki

    1999-01-01

    We identified Xenopus pericentriolar material-1 (PCM-1), which had been reported to constitute pericentriolar material, cloned its cDNA, and generated a specific pAb against this molecule. Immunolabeling revealed that PCM-1 was not a pericentriolar material protein, but a specific component of centriolar satellites, morphologically characterized as electron-dense granules, ∼70–100 nm in diameter, scattered around centrosomes. Using a GFP fusion protein with PCM-1, we found that PCM-1–containing centriolar satellites moved along microtubules toward their minus ends, i.e., toward centrosomes, in live cells, as well as in vitro reconstituted asters. These findings defined centriolar satellites at the molecular level, and explained their pericentriolar localization. Next, to understand the relationship between centriolar satellites and centriolar replication, we examined the expression and subcellular localization of PCM-1 in ciliated epithelial cells during ciliogenesis. When ciliogenesis was induced in mouse nasal respiratory epithelial cells, PCM-1 immunofluorescence was markedly elevated at the apical cytoplasm. At the electron microscopic level, anti–PCM-1 pAb exclusively labeled fibrous granules, but not deuterosomes, both of which have been suggested to play central roles in centriolar replication in ciliogenesis. These findings suggested that centriolar satellites and fibrous granules are identical novel nonmembranous organelles containing PCM-1, which may play some important role(s) in centriolar replication. PMID:10579718

  11. Satellite broadcasting

    NASA Astrophysics Data System (ADS)

    Gregory, D.; Rainger, P.; Harvey, R. V.; Jennings, A.

    Questions related to direct broadcasting satellites are addressed with attention given to celestial mechanics, synchronous orbits, propagation, international plans, domestic installation, related laws and system costs. The role of the World Administrative Planning Conference (WARC) organization is discussed and contrasted with that of the regional administrative radio conference. Topics related to the field of law include coverage and overspill, regulation and control, copyrights and international organizations. Alternative ways of estimating direct broadcasting system costs are presented with consideration given to satellite costs as a function of mass, launch costs and system costs as a function of power.

  12. Some background about satellites

    NASA Technical Reports Server (NTRS)

    Burns, Joseph A.

    1986-01-01

    Four tables of planetary and satellite data are presented which list satellite discoveries, planetary parameters, satellite orbits, and satellite physical properties respectively. A scheme for classifying the satellites is provided and it is noted that most known moons fall into three general classes: regular satellites, collisional shards, and irregular satellites. Satellite processes are outlined with attention given to origins, dynamical and thermal evolution, surface processes, and composition and cratering. Background material is provided for each family of satellites.

  13. Satellite description

    NASA Astrophysics Data System (ADS)

    Gillett, F. C.; Clegg, P. E.; Neugebauer, G.; Langford, D.; Pouw, A.; Irace, W.; Houck, J.

    The onboard computers and their associated software, the attitude control system, and data recording and the communication links of the infrared astronomy satellite (TRAS) are discussed. The IRAS telescope system is considered in detail. Attention is directed towards the cryogenics, thermal control, optics, focal plane assembly, and electronics associated with the telescope system.

  14. Virtual Satellite

    NASA Technical Reports Server (NTRS)

    Hammrs, Stephan R.

    2008-01-01

    Virtual Satellite (VirtualSat) is a computer program that creates an environment that facilitates the development, verification, and validation of flight software for a single spacecraft or for multiple spacecraft flying in formation. In this environment, enhanced functionality and autonomy of navigation, guidance, and control systems of a spacecraft are provided by a virtual satellite that is, a computational model that simulates the dynamic behavior of the spacecraft. Within this environment, it is possible to execute any associated software, the development of which could benefit from knowledge of, and possible interaction (typically, exchange of data) with, the virtual satellite. Examples of associated software include programs for simulating spacecraft power and thermal- management systems. This environment is independent of the flight hardware that will eventually host the flight software, making it possible to develop the software simultaneously with, or even before, the hardware is delivered. Optionally, by use of interfaces included in VirtualSat, hardware can be used instead of simulated. The flight software, coded in the C or C++ programming language, is compilable and loadable into VirtualSat without any special modifications. Thus, VirtualSat can serve as a relatively inexpensive software test-bed for development test, integration, and post-launch maintenance of spacecraft flight software.

  15. Satellite Bioclimatology.

    NASA Astrophysics Data System (ADS)

    Goward, Samuel N.

    1989-07-01

    Satellite-acquired, remotely sensed observations of the earth's land areas are substatially advancing knowledge of global vegetation patterns. Recognition that combined visible/near infrared spectral reflectance observations are a general indicator of the presence, condition and magnitude of vegetation foliage provides a basis for explanation. This information is of considerable value in climatic research because of the links between climate variables and vegetation foliage. Presence of vegetation foliage is predominantly determined by a combination of local beat and moisture conditions. In turn, foliar presence determines local rates of photosynthesis, affects surface albedo, and influences local rates of evapotranspiration as well as other elements of surface energy/mass balance. Availability of these remotely sensed data provides, for the first time, a consistent, global means to directly study interactions between climate and vegetation. This understanding is now being incorporated in climatological research and should improve understanding of macroscale bioclimatology. Remote sensing technology and understanding of this technology are continuing to develop rapidly and further major advances in this new field of `satellite bioclimatology' can be expected in the near future.

  16. Meteorological satellites

    NASA Astrophysics Data System (ADS)

    1981-10-01

    Meteor-2 (second generation meteorological satellite) and an experimental satellite on which instruments are being tested and modified for the requirements of hydrometeorology and a determination of natural resources are presently operational in the U.S.S.R. Television devices with a 1-10 km terrain image resolution operating in the visible and infrared region are used to determine the space system, velocity and direction of cloud movements and provide information about the snow and ice cover, cyclones, storms, vortices in the atmosphere, and velocity and direction of wind. Images with a 50-1000 m resolution make possible geological and hydrological surveys, an evaluation of the state of vegetation and crops, detection of forest fires, determination of pollution of the atmosphere and sea and determination of optimal fishing regions in the ocean. Measurement of the intensity of atmospheric radiation in narrow infrared regions and very high frequencies allows remote evaluation of the temperature and humidity distribution in the vertical cross section of the Earth's atmosphere.

  17. Satellite altimetry

    NASA Technical Reports Server (NTRS)

    Cheney, Robert E.

    1992-01-01

    Since altimetry data are not really old enough to use the term data archaeology, Mr. Cheney referred to the stewardship of these data. He noted that it is very important to document the basis for an altimetry data set as the algorithms and corrections used to arrive at the Geophysical Data Record (GDR) have been improving and are continuing to improve the precision of sea level data derived from altimetry. He noted that the GEOSAT Exact Repeat Mission (ERM) data set has recently been reprocessed by his organization in the National Ocean Service of NOAA and made available to the scientific community on CD/ROM disks by the National Oceanographic Data Center of the U.S. (NODC). The new data set contains a satellite orbit more precise by an order of magnitude together with an improved water vapor correction. A new, comprehensive GDR Handbook has also been prepared.

  18. Satellites in Education.

    ERIC Educational Resources Information Center

    Jones, David

    1988-01-01

    Describes the methods and materials used to obtain satellite pictures from weather satellites. Discusses possible physics lessons which can be done using this equipment including orbital mechanics, and how the satellite works. (CW)

  19. Iodine Satellite

    NASA Technical Reports Server (NTRS)

    Kamhawi, Hani; Dankanich, John; Martinez, Andres; Petro, Andrew

    2015-01-01

    The Iodine Satellite (iSat) spacecraft will be the first CubeSat to demonstrate high change in velocity from a primary propulsion system by using Hall thruster technology and iodine as a propellant. The mission will demonstrate CubeSat maneuverability, including plane change, altitude change and change in its closest approach to Earth to ensure atmospheric reentry in less than 90 days. The mission is planned for launch in fall 2017. Hall thruster technology is a type of electric propulsion. Electric propulsion uses electricity, typically from solar panels, to accelerate the propellant. Electric propulsion can accelerate propellant to 10 times higher velocities than traditional chemical propulsion systems, which significantly increases fuel efficiency. To enable the success of the propulsion subsystem, iSat will also demonstrate power management and thermal control capabilities well beyond the current state-of-the-art for spacecraft of its size. This technology is a viable primary propulsion system that can be used on small satellites ranging from about 22 pounds (10 kilograms) to more than 1,000 pounds (450 kilograms). iSat's fuel efficiency is ten times greater and its propulsion per volume is 100 times greater than current cold-gas systems and three times better than the same system operating on xenon. iSat's iodine propulsion system consists of a 200 watt (W) Hall thruster, a cathode, a tank to store solid iodine, a power processing unit (PPU) and the feed system to supply the iodine. This propulsion system is based on a 200 W Hall thruster developed by Busek Co. Inc., which was previously flown using xenon as the propellant. Several improvements have been made to the original system to include a compact PPU, targeting greater than 80 percent reduction in mass and volume of conventional PPU designs. The cathode technology is planned to enable heaterless cathode conditioning, significantly increasing total system efficiency. The feed system has been designed to

  20. Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Merline, W. J.

    2001-11-01

    Discovery and study of small satellites of asteroids or double asteroids can yield valuable information about the intrinsic properties of asteroids themselves and about their history and evolution. Determination of the orbits of these moons can provide precise masses of the primaries, and hence reliable estimates of the fundamental property of bulk density. This reveals much about the composition and structure of the primary and will allow us to make comparisons between, for example, asteroid taxonomic type and our inventory of meteorites. The nature and prevalence of these systems will also give clues as to the collisional environment in which they formed, and have further implications for the role of collisions in shaping our solar system. A decade ago, binary asteroids were more of a theoretical curiosity. In 1993, the Galileo spacecraft allowed the first undeniable detection of an asteroid moon, with the discovery of Dactyl, a small moon of Ida. Since that time, and particularly in the last year, the number of known binaries has risen dramatically. Previously odd-shaped and lobate near-Earth asteroids, observed by radar, have given way to signatures indicating, almost certainly, that at least four NEAs are binary systems. The tell-tale lightcurves of several other NEAs reveal a high likelihood of being double. Indications are that among the NEAs, there may be a binary frequency of several tens of percent. Among the main-belt asteroids, we now know of 6 confirmed binary systems, although their overall frequency is likely to be low, perhaps a few percent. The detections have largely come about because of significant advances in adaptive optics systems on large telescopes, which can now reduce the blurring of the Earth's atmosphere to compete with the spatial resolution of space-based imaging (which itself, via HST, is now contributing valuable observations). Most of these binary systems have similarities, but there are important exceptions. Searches among other

  1. Outer planet satellites

    SciTech Connect

    Schenk, P.M. )

    1991-01-01

    Recent findings on the outer-planet satellites are presented, with special consideration given to data on the rheologic properties of ice on icy satellites, the satellite surfaces and exogenic processes, cratering on dead cratered satellites, volcanism, and the interiors of outer-planet satellites. Particular attention is given to the state of Titan's surface and the properties of Triton, Pluto, and Charon. 210 refs.

  2. China's satellite communications discussed

    NASA Astrophysics Data System (ADS)

    Ruhou, Z.

    1986-04-01

    In 1972, China began to enter the age of satellite comunications, and it was realized that satellites could play a large role in television transmission in China. The experimental broadcasting of satellite television programs was begun in 1978, and satisfactory results were obtained. The success of the television transmission demonstration has led to important decisions regarding development of a domestic satellite communications system. Before specialized communications satellites are launched, the decision was made to lease an international communications satellite transmitter. The responsibility of the ground stations were discussed.

  3. Satellite orbit predictor

    NASA Technical Reports Server (NTRS)

    Friedman, Morton l.; Garrett, James, Major

    An analog aid to determine satellite coverage of Emergency Locator Transmitters Emergency Position Indicating Radio Beacon (ELT/EPIRB) distress incidence is discussed. The satellite orbit predictor is a graphical aid for determining the relationship between the satellite orbit, antenna coverage of the spacecraft and coverage of the Local User Terminal. The predictor allows the user to quickly visualize if a selected position will probably be detected and is composed of a base map and a satellite track overlay for each satellite.A table of equator crossings for each satellite is included.

  4. Galileo satellite antenna modeling

    NASA Astrophysics Data System (ADS)

    Steigenberger, Peter; Dach, Rolf; Prange, Lars; Montenbruck, Oliver

    2015-04-01

    The space segment of the European satellite navigation system Galileo currently consists of six satellites. Four of them belong to the first generation of In-Orbit Validation (IOV) satellites whereas the other two are Full Operational Capability (FOC) satellites. High-precision geodetic applications require detailed knowledge about the actual phase center of the satellite and receiver antenna. The deviation of this actual phase center from a well-defined reference point is described by phase center offsets (PCOs) and phase center variations (PCVs). Unfortunately, no public information is available about the Galileo satellite antenna PCOs and PCVs, neither for the IOV, nor the FOC satellites. Therefore, conventional values for the IOV satellite antenna PCOs have been adopted for the Multi-GNSS experiment (MGEX) of the International GNSS Service (IGS). The effect of the PCVs is currently neglected and no PCOs for the FOC satellites are available yet. To overcome this deficiency in GNSS observation modeling, satellite antenna PCOs and PCVs are estimated for the Galileo IOV satellites based on global GNSS tracking data of the MGEX network and additional stations of the legacy IGS network. Two completely independent solutions are computed with the Bernese and Napeos software packages. The PCO and PCV values of the individual satellites are analyzed and the availability of two different solutions allows for an accuracy assessment. The FOC satellites are built by a different manufacturer and are also equipped with another type of antenna panel compared to the IOV satellites. Signal transmission of the first FOC satellite has started in December 2014 and activation of the second satellite is expected for early 2015. Based on the available observations PCO estimates and, optionally PCVs of the FOC satellites will be presented as well. Finally, the impact of the new antenna model on the precision and accuracy of the Galileo orbit determination is analyzed.

  5. Satellite broadcasting in Europe

    NASA Astrophysics Data System (ADS)

    Bartholome, P.

    1984-05-01

    Three main communications services are recognized by the International Telecommunications Union: the Fixed Service, the Mobile Service and the Broadcasting Service. In Europe, EUTELSAT has just begun to exploit the first ECS satellite. The ESA-launched satellite was originally designed to provide an international public telecommunication service, however, the satellite will be used now almost exclusively for TV program distribution, while a second ECS satellite will be used for telephony. Despite plans for the launch of a third, countries in Europe are looking to other organizations such as INTELSAT for greater satellite capacity. Other organizations include Unisat, DFS/Copernicus, GDL, and Videosat. Both satellite and cable networks will increase the program-viewing audience, thus encouraging plans for a pan-European television service intended for an international audience. Although the combination of cable networks and distribution satellites looks promising, high-power broadcasting satellites will play an important role because of flexibility and additional program distribution.

  6. Stereo Measurements from Satellites

    NASA Technical Reports Server (NTRS)

    Adler, R.

    1982-01-01

    The papers in this presentation include: 1) 'Stereographic Observations from Geosynchronous Satellites: An Important New Tool for the Atmospheric Sciences'; 2) 'Thunderstorm Cloud Top Ascent Rates Determined from Stereoscopic Satellite Observations'; 3) 'Artificial Stereo Presentation of Meteorological Data Fields'.

  7. Magnetospheres: Jupiter, Satellite Interactions

    NASA Astrophysics Data System (ADS)

    Neubauer, F.; Murdin, P.

    2000-11-01

    Most of the satellites of Jupiter, notably the large Galilean satellites Io, Europa, Ganymede and Callisto (see JUPITER: SATELLITES), orbit deep inside the magnetosphere of Jupiter (see JUPITER: MAGNETOSPHERE) and are therefore immersed in the flow of magnetospheric plasma (made of a mixture of electrons and ions) and subjected to an interaction with the strong Jovian magnetic field. These intera...

  8. [Theme Issue: Communications Satellites.

    ERIC Educational Resources Information Center

    Howkins, John, Ed.

    1976-01-01

    One section of this journal is devoted to issues involving broadcast satellites. Separate articles discuss the need for international planning of satellite broadcasting, decisions made at the 1971 World Administrative Radio Conference for Space Telecommunications, potential problems in satellite broadcasting, a series of proposals drawn up by the…

  9. Survey: National Environmental Satellite Service

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The national Environmental Satellite Service (NESS) receives data at periodic intervals from satellites of the Synchronous Meteorological Satellite/Geostationary Operational Environmental Satellite series and from the Improved TIROS (Television Infrared Observational Satellite) Operational Satellite. Within the conterminous United States, direct readout and processed products are distributed to users over facsimile networks from a central processing and data distribution facility. In addition, the NESS Satellite Field Stations analyze, interpret, and distribute processed geostationary satellite products to regional weather service activities.

  10. Digital satellite communications

    NASA Astrophysics Data System (ADS)

    Ha, T. T.

    1986-06-01

    The use of satellite communications in point-to-multipoint transmission of data is studied. The theory, systems, and equipment for satellite communications are described. The topics of satellite orbits, satellite construction, earth station equipment, and the analysis of the satellite link are discussed. Different types of digital modulation for carrier transmission, and techniques for enhancing the transmission capacity, such as digital speech interpolation and demand assignment, are examined. Techniques and equipment for performing the multiple access-broadcasting functions including FDMA, TDMA, DAMA, CDMA, and random access are considered.

  11. Fundamentals of satellite navigation

    NASA Astrophysics Data System (ADS)

    Stiller, A. H.

    The basic operating principles and capabilities of conventional and satellite-based navigation systems for air, sea, and land vehicles are reviewed and illustrated with diagrams. Consideration is given to autonomous onboard systems; systems based on visible or radio beacons; the Transit, Cicada, Navstar-GPS, and Glonass satellite systems; the physical laws and parameters of satellite motion; the definition of time in satellite systems; and the content of the demodulated GPS data signal. The GPS and Glonass data format frames are presented graphically, and tables listing the GPS and Glonass satellites, their technical characteristics, and the (past or scheduled) launch dates are provided.

  12. TSS Satellite Overview

    NASA Technical Reports Server (NTRS)

    Manarini, G.

    1985-01-01

    The responsibilities of NASA and PSN/CNR in the tethered satellite system cooperative program are listed and PSN/CNR-AIT system support and technologies studies are summarized. Results are given for investigations of active vs. passive satellite trade offs; analysis of alternative maneuvers; satellite attitude and position determination analysis failure modes analysis; moveable boom dynamic analysis; double tethered satellite system; and thermo/dynamic analysis for 100 km to 120 km altitude range. Objectives for the space plasma science mission and its applications are outlined and the TSS satellite configuration is highlighted. Programmatic aspects are included.

  13. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1971-01-01

    Satellite altitude determination uncertainties are discussed from the standpoint of the GEOS-C satellite. GEOS-C will be tracked by a number of the conventional satellite tracking systems, as well as by two advanced systems; a satellite-to-satellite tracking system and lasers capable of decimeter accuracies which are being developed in connection with the Goddard Earth and Ocean Dynamics Applications program. The discussion is organized in terms of a specific type of GEOS-C orbit which would satisfy a number of scientific objectives including the study of the gravitational field by means of both the altimeter and the satellite-to-satellite tracking system, studies of tides, and the Gulf Stream meanders.

  14. Communication satellite applications

    NASA Astrophysics Data System (ADS)

    Pelton, Joseph N.

    The status and future of the technologies, numbers and services provided by communications satellites worldwide are explored. The evolution of Intelsat satellites and the associated earth terminals toward high-rate all-digital telephony, data, facsimile, videophone, videoconferencing and DBS capabilities are described. The capabilities, services and usage of the Intersputnik, Eutelsat, Arabsat and Palapa systems are also outlined. Domestic satellite communications by means of the Molniya, ANIK, Olympus, Intelsat and Palapa spacecraft are outlined, noting the fast growth of the market and the growing number of different satellite manufacturers. The technical, economic and service definition issues surrounding DBS systems are discussed, along with presently operating and planned maritime and aeronautical communications and positioning systems. Features of search and rescue and tracking, data, and relay satellite systems are summarized, and services offered or which will be offered by every existing or planned communication satellite worldwide are tabulated.

  15. Satellite services system overview

    NASA Technical Reports Server (NTRS)

    Rysavy, G.

    1982-01-01

    The benefits of a satellite services system and the basic needs of the Space Transportation System to have improved satellite service capability are identified. Specific required servicing equipment are discussed in terms of their technology development status and their operative functions. Concepts include maneuverable television systems, extravehicular maneuvering unit, orbiter exterior lighting, satellite holding and positioning aid, fluid transfer equipment, end effectors for the remote manipulator system, teleoperator maneuvering system, and hand and power tools.

  16. Satellite networks for education

    NASA Technical Reports Server (NTRS)

    Singh, J. P.; Morgan, R. P.; Rosenbaum, F. J.

    1972-01-01

    Satellite based educational networking is discussed with particular attention given to the potential uses of communications satellites to help meet educational needs in the United states. Four major subject areas were covered; (1) characteristics and structure of networks, (2) definition of pressures within educational establishment that provide motivation for various types of networks, (3) examination of current educational networking status for educational radio and television, instructional television fixed services, inter- and intra-state educational communication networks, computer networks, and cable television for education, and (4) identification of possible satellite based educational telecommunication services and three alternatives for implementing educational satellite systems.

  17. Satellite communication antenna technology

    NASA Technical Reports Server (NTRS)

    Mittra, R. (Editor); Imbriale, W. A. (Editor); Maanders, E. J. (Editor)

    1983-01-01

    A general overview of current technology in the field of communication satellite antennas is presented. Among the topics discussed are: the design of multiple beam systems; frequency reuse; and polarization control of antenna measurements. Consideration is also given to: contour beam synthesis; dual shaped reflector synthesis; beam shaping; and offset reflector design. The applications of the above technologies to present and future generations of communications satellites is considered, with emphasis given to such systems as: the Intelsats; the Defense Satellite Communications System, (DSCS-III); Satellite Business System (SBS), and Comstar.

  18. Satellite Antenna Systems

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Through the Technology Affiliates Program at the Jet Propulsion Laboratory, the ACTS antenna system was transferred from experimental testing status to commercial development with KVH Industries, Inc. The ACTS design enables mobile satellite antennas to remain pointed at the satellite, regardless of the motion or vibration on which it is mounted. KVH's first product based on the ACTS design is a land-mobile satellite antenna system that will enable direct broadcast satellite television aboard moving trucks, recreational vehicles, trains, and buses. Future products could include use in broadcasting, emergency medical and military vehicles.

  19. Methods of satellite oceanography

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1985-01-01

    The theoretical basis for remote sensing measurements of climate and ocean dynamics is examined. Consideration is given to: the absorption of electromagnetic radiation in the atmosphere; scattering in the atmosphere; and satellite observations using visible light. Consideration is also given to: the theory of radio scatter from the sea; scatter of centimeter waves from the sea; and the theory of operation of synthetic aperture radars. Additional topics include: the coordinate systems of satellite orbits for oceanographic remote sensing applications; the operating features of the major U.S. satellite systems for viewing the ocean; and satellite altimetry.

  20. Satellite Tracking System

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Researchers at the Center for Aerospace Sciences of the University of North Dakota (UND), Grand Forks, used three NASA Computer programs (SANDTRACKS, ODG, NORAD) to develop a Satellite Tracking System for real time utilization of TIROS weather/environment satellite information. SANDTRACKS computes the satellite's position relative to the Earth. ODG allows plotting a view of Earth as seen by the satellite. NORAD computes sight direction, visibility times and maximum elevation angle during each orbit. With the system, UND's Earth System Science Institute will be able to routinely monitor agricultural and environmental conditions of the Northern Plains.

  1. Processing of satellite imagery at the National Environmental Satellite Service

    NASA Technical Reports Server (NTRS)

    Crowe, M.

    1977-01-01

    The National Environmental Satellite Service (NESS) image product processing system is described. Other topics discussed include: (1) image processing of polar-orbiter satellite data; (2) image processing of geostationary satellite data; and (3) quality assurance and product monitoring.

  2. Communication satellite technology trends

    NASA Technical Reports Server (NTRS)

    Cuccia, Louis

    1986-01-01

    A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

  3. Communications technology satellite

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A description of the Communications Technology Satellite (CTS), its planned orbit, its experiments, and associated ground facilities was given. The communication experiments, to be carried out by a variety of groups in both the United States and Canada, include tele-education, tele-medicine, community interaction, data communications and broadcasting. A historical summary of communications satellite development was also included.

  4. Amateur Radio Satellite Communications.

    ERIC Educational Resources Information Center

    Koch, David P.

    The Amateur Radio Satellite Communications project had, as its goal, the assembly of an amateur radio satellite station in a high school physics classroom. Specific objectives were to provide: (1) a special source of interest as a motivator for attracting students and building public relations; (2) a center of interest as a motivator for the study…

  5. Satellite Teleconference Final Report.

    ERIC Educational Resources Information Center

    Elgin Community Coll., IL.

    The vocational education satellite teleconference project accomplished two goals: (1) identified, acquired, copied, and distributed to the Illinois Vocational Curriculum Center 100 marketing or training videotapes for staff development and classroom use; and (2) provided from 15-25 variable time (1- to 3-hour) satellite teleconferences in four…

  6. Audio direct broadcast satellites

    NASA Technical Reports Server (NTRS)

    Miller, J. E.

    1983-01-01

    Satellite sound broadcasting is, as the name implies, the use of satellite techniques and technology to broadcast directly from space to low-cost, consumer-quality receivers the types of sound programs commonly received in the AM and FM broadcast bands. It would be a ubiquitous service available to the general public in the home, in the car, and out in the open.

  7. Advanced communications satellites

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1980-01-01

    The increase in demand for satellite communications services brought about shortages in available transponder capacity, especially at C-band. Interest shifted to the Ku-band frequency and currently carriers are rapidly moving to secure orbital slots for future satellite development. Projections of communications service demands over the next decade indiate growth in voice, data, and video services such that saturation of both C-band and Ku-band will occur by 1990. Emphasis must and will shift to Ka-band (20/30 GHz) frequency for fixed-satellite service. Advanced technologies such as multibeam antennas coupled with on-board satellite switching to allow implementation in this band of very high capacity satellite systems will be applied to meet the demand. Satellite system concepts that are likely in the 1990's and are likely to bring a new dimension to satellite delivered communication service are presented. The NASA 30/20 GHz communications satellite system demonstration program is discussed with emphasis on the related technology development.

  8. Laser Geodynamics Satellite I

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The LAGEOS I (Laser Geodynamics Satellite) was developed and launched by the Marshall Space Flight Center on May 4, 1976 from Vandenberg Air Force Base, California . The two-foot diameter satellite orbited the Earth from pole to pole and measured the movements of the Earth's surface.

  9. Telecommunications satellite systems

    NASA Astrophysics Data System (ADS)

    Ramat, Pierre

    1992-12-01

    A survey of the telecommunications satellite field is presented. After a review of the historical and regulatory background, the main technical features of satellite networks are analyzed, and existing international and national systems are considered. Particular attention is given to Intelsat, Inmarsat, Eutelsat, and Telecom 1 and 2. Future technical and economic trends are then projected.

  10. Satellites in Schools.

    ERIC Educational Resources Information Center

    Underwood, C. I.; And Others

    1987-01-01

    Discusses the use of satellite data in physics classrooms. Describes the apparatus that can be used to collect and analyze data. Provides examples of how telemetry data transmitted by the satellite UoSAT-2 can be used not only in teaching physics, but also in geography, mathematics, and information technology. (TW)

  11. Outer planets satellites

    NASA Technical Reports Server (NTRS)

    Morrison, D.

    1983-01-01

    The present investigation takes into account the published literature on outer planet satellites for 1979-1982. It is pointed out that all but three (the moon and the two Martian satellites) of the known planetary satellites are found in the outer solar system. Most of these are associated with the three regular satellite systems of Jupiter, Saturn, and Uranus. The largest satellites are Titan in the Saturn system and Ganymede and Callisto in the Jupiter system. Intermediate in size between Mercury and Mars, each has a diameter of about 5000 km. Presumably each has an internal composition about 60 percent rock and 40 ice, and each is differentiated with a dense core extending out about 75 percent of the distance to the surface, with a mantle of high-pressure ice and a crust of ordinary ice perhaps 100 km thick. Attention is also given to Io, Europa, the icy satellites of Saturn, the satellites of Uranus, the small satellites of Jupiter and Saturn, Triton and the Pluto system, and plans for future studies.

  12. Signals from Communications Satellites.

    ERIC Educational Resources Information Center

    Thomsen, Volker

    1996-01-01

    Discusses the Doppler effect for relative motion between a source of waves and an observer and the orbital dynamics of communications satellites. Presents preliminary calculations of the satellite's altitude and linear velocity using only the concepts of the Doppler shift and the mechanics of motion in a circular path. (JRH)

  13. The Satellite Situation Center

    NASA Technical Reports Server (NTRS)

    Teague, M. J.; Sawyer, D. M.; Vette, J. I.

    1982-01-01

    Considerations related to the early planning for the International Magnetospheric Study (IMS) took into account the desirability of an establishment of specific entities for generating and disseminating coordination information for both retrospective and predictive periods. The organizations established include the IMS/Satellite Situation Center (IMS/SSC) operated by NASA. The activities of the SSC are related to the preparation of reports on predicted and actually achieved satellite positions, the response to inquiries, the compilation of information on satellite experiments, and the issue of periodic status summaries. Attention is given to high-altitude satellite services, other correlative satellite services, non-IMS activities of the SSC, a summary of the SSC request activity, and post-IMS and future activities.

  14. Satellite networks for education.

    NASA Technical Reports Server (NTRS)

    Singh, J. P.; Morgan, R. P.; Rosenbaum, F. J.

    1972-01-01

    Consideration of satellite-based educational networking. The characteristics and structure of networks are reviewed, and pressures within the educational establishment that are providing motivation for various types of networks are discussed. A number of studies are cited in which networking needs for educational sectors and services are defined. The current status of educational networking for educational radio and television, instructional television fixed services, inter- and intrastate educational communication networks, computer networks, cable television for education, and continuing and proposed educational experiments using NASA's Applications Technology Satellites is reviewed. Possible satellite-based educational telecommunication services and three alternatives for implementing educational satellite systems are described. Some remarks are made concerning public policy aspects of future educational satellite system development.

  15. Satellite Services Workshop, Volume 1

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Key issues associated with the orbital servicing of satellites are examined including servicing spacecraft and equipment, servicing operations, economics, satellite design, docking and berthing, and fluid management.

  16. Skeletal muscle satellite cells

    NASA Technical Reports Server (NTRS)

    Schultz, E.; McCormick, K. M.

    1994-01-01

    Evidence now suggests that satellite cells constitute a class of myogenic cells that differ distinctly from other embryonic myoblasts. Satellite cells arise from somites and first appear as a distinct myoblast type well before birth. Satellite cells from different muscles cannot be functionally distinguished from one another and are able to provide nuclei to all fibers without regard to phenotype. Thus, it is difficult to ascribe any significant function to establishing or stabilizing fiber type, even during regeneration. Within a muscle, satellite cells exhibit marked heterogeneity with respect to their proliferative behavior. The satellite cell population on a fiber can be partitioned into those that function as stem cells and those which are readily available for fusion. Recent studies have shown that the cells are not simply spindle shaped, but are very diverse in their morphology and have multiple branches emanating from the poles of the cells. This finding is consistent with other studies indicating that the cells have the capacity for extensive migration within, and perhaps between, muscles. Complexity of cell shape usually reflects increased cytoplasmic volume and organelles including a well developed Golgi, and is usually associated with growing postnatal muscle or muscles undergoing some form of induced adaptive change or repair. The appearance of activated satellite cells suggests some function of the cells in the adaptive process through elaboration and secretion of a product. Significant advances have been made in determining the potential secretion products that satellite cells make. The manner in which satellite cell proliferative and fusion behavior is controlled has also been studied. There seems to be little doubt that cellcell coupling is not how satellite cells and myofibers communicate. Rather satellite cell regulation is through a number of potential growth factors that arise from a number of sources. Critical to the understanding of this form

  17. Land mobile communications satellite

    NASA Astrophysics Data System (ADS)

    Carnebianca, C.; Pavesi, B.; Tuozzi, A.

    1986-09-01

    The economic value and salient technical and operational characteristics of a European Land Mobile Communication Satellite (LMCS) to complement and supplement the demand for mobile services of Western European countries in the 1995 to 2005 time frames were assessed. A significant future expansion of demand for LCMS services on the part of the public is anticipated. Important augmentations of current service capabilities could be achieved by a satellite service, improving the overall system performances and/or assisting the PTT's in containing their investments in the required infrastructure. The satellite service itself could represent a profitable revenue producer.

  18. Advanced communications satellite systems

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.

    1983-01-01

    There is a rapidly growing demand for satellite circuits, particularly for domestic service within the U.S. NASA's current program is aimed at developing the high risk, advanced satellite communications technologies required to significantly increase the capacity of future satellite communications systems. Attention is given to aspects of traffic distribution and service scenario, problems related to effects of rain attenuation, details regarding system configuration, a 30/20 GHz technology development approach, an experimental flight system, the communications payload for the experimental flight system, a typical experiment flight system coverage, and a typical three axis stabilized flight spacecraft.

  19. Satellite Breakup Risk Mitigation

    NASA Technical Reports Server (NTRS)

    Leleux, Darrin P.; Smith, Jason T.

    2006-01-01

    Many satellite breakups occur as a result of an explosion of stored energy on-board spacecraft or rocket-bodies. These breakups generate a cloud of tens or possibly hundreds of thousands of debris fragments which may pose a transient elevated threat to spaceflight crews and vehicles. Satellite breakups pose a unique threat because the majority of the debris fragments are too small to be tracked from the ground. The United States Human Spaceflight Program is currently implementing a risk mitigation strategy that includes modeling breakup events, establishing action thresholds, and prescribing corresponding mitigation actions in response to satellite breakups.

  20. Satellites save lives

    NASA Astrophysics Data System (ADS)

    Bulloch, Chris

    The use of satellites, in particular weather satellites, to detect emergency transmitter signals for search and rescue (SAR) operations is studied. The benefits provided to SAR operations by the Doppler processing of signals and the assignment of the 100-kHz band, 406.0-406.1 MHz in UHF region for satellite SAR services are discussed. The capabilities of Argos, a data collection system, and its function in SAR operations are described. Future developments for the COSPAS-SARSAT system are considered.

  1. Overview of commercial satellite communications

    NASA Astrophysics Data System (ADS)

    Beakley, G. W.

    1984-07-01

    A brief history of communications satellites is presented, taking into account the launching of Sputnik 1 in October 1957, the Explorer 1 in January of 1958, the launch of the Score as the world's first active communications satellite in December 1958, the Communications Satellite Act in 1962, and the launch of 'Early Bird' in 1964. The Intelsat satellites are considered along with maritime satellite communications, the U.S. domestic satellite systems, Alaskan satellite communications, cable television, broadcast TV stations, print media, the hotel/motel industry as a large market for satellite communications terminals, the opening of a minicable and satellite master antenna TV market for TV receive-only systems, and business telecommunications earth terminals. Attention is also given to future directions regarding satellite positions, the concept of 'video-plus', and direct broadcast satellites.

  2. Biological satellite Kosmos-936

    NASA Technical Reports Server (NTRS)

    Vedeshin, L. A.

    1978-01-01

    A description is given of physiological experiments performed on the biological satellite Kosmos-936. Other experiments to determine the electrostatic and dielectric responses to the effects of cosmic radiation are discussed.

  3. AUSSAT mobile satellite services

    NASA Technical Reports Server (NTRS)

    Nowland, Wayne L.; Wagg, Michael; Simpson, Daniel

    1988-01-01

    An overview of AUSSAT's planned mobile satellite system is given. The development program which is being undertaken to achieve the 1992 service date is described. Both business and technical aspects of the development program are addressed.

  4. Domestic Communication Satellites

    ERIC Educational Resources Information Center

    Horowitz, Andrew

    1974-01-01

    A discussion of the Federal Communications Commission's new policy on domestic satellites in light of our 1) military and economic history; 2) corporate interests; 3) citizen surveillance; and 4) media control. (HB)

  5. Meteorological satellite accomplishments

    NASA Technical Reports Server (NTRS)

    Allison, L. J.; Arking, A.; Bandeen, W. R.; Shenk, W. E.; Wexler, R.

    1974-01-01

    The various types of meteorological satellites are enumerated. Vertical sounding, parameter extraction technique, and both macroscale and mesoscale meteorological phenomena are discussed. The heat budget of the earth-atmosphere system is considered, along with ocean surface and hydrology.

  6. Aiming a Satellite Dish.

    ERIC Educational Resources Information Center

    Zebrowski, Ernest, Jr.

    1988-01-01

    Develops a pair of equations for calculating the elevation and azimuth angles for the various satellites. Uses 3-dimensional vector difference calculations. Provides a practical example, figures, and table. (YP)

  7. Disaster warning satellite study

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The Disaster Warning Satellite System is described. It will provide NOAA with an independent, mass communication system for the purpose of warning the public of impending disaster and issuing bulletins for corrective action to protect lives and property. The system consists of three major segments. The first segment is the network of state or regional offices that communicate with the central ground station; the second segment is the satellite that relays information from ground stations to home receivers; the third segment is composed of the home receivers that receive information from the satellite and provide an audio output to the public. The ground stations required in this system are linked together by two, separate, voice bandwidth communication channels on the Disaster Warning Satellites so that a communications link would be available in the event of disruption of land line service.

  8. Weather, land satellite sale

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    President Ronald Reagan announced on March 8 plans to sell to private industry the nation's land and meteorological remote-sensing satellites, including the responsibility for any future ocean-observing systems. According to the plan, the private firm successful in its bid to buy the five satellites would sell back to the government the data received by the satellites. The Reagan administration says the sale will save money and will put activities appropriate for commercial ventures into the commercial sector. Response to the announcement from scientists and congressmen has been anything but dulcet; one senator, in fact, charges that the Commerce Department and the corporation most likely to purchase the satellites are engaged in a ‘sweetheart deal.’

  9. Measuring Phytoplankton From Satellites

    NASA Technical Reports Server (NTRS)

    Davis, C. O.

    1989-01-01

    Present and future methods examined. Report reviews methods of calculating concentration of phytoplankton from satellite measurements of color of ocean and using such calculations to estimate productivity of phytoplankton.

  10. Orbit determination accuracies using satellite-to-satellite tracking

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.; Argentiero, P. D.; Schmid, P. E.

    1977-01-01

    The uncertainty in relay satellite sate is a significant error source which cannot be ignored in the reduction of satellite-to-satellite tracking data. Based on simulations and real data reductions, it is numerically impractical to use simultaneous unconstrained solutions to determine both relay and user satellite epoch states. A Bayesian or least squares estimation technique with an a priori procedure is presented which permits the adjustment of relay satellite epoch state in the reduction of satellite-to-satellite tracking data without the numerical difficulties introduced by an ill-conditioned normal matrix.

  11. Epos TCS Satellite Data

    NASA Astrophysics Data System (ADS)

    Manunta, Michele; Mandea, Mioara; Fernández-Turiel, José Luis; Stramondo, Salvatore; Wright, Tim; Walter, Thomas; Bally, Philippe; Casu, Francesco; Zeni, Giovanni; Buonanno, Sabatino; Zinno, Ivana; Tizzani, Pietro; Castaldo, Raffaele; Ostanciaux, Emilie; Diament, Michel; Hooper, Andy; Maccaferri, Francesco; Lanari, Riccardo

    2016-04-01

    TCS Satellite Data is devoted to provide Earth Observation (EO) services, transversal with respect to the large EPOS community, suitable to be used in several application scenarios. In particular, the main goal is to contribute with mature services that have already well demonstrated their effectiveness and relevance in investigating the physical processes controlling earthquakes, volcanic eruptions and unrest episodes as well as those driving tectonics and Earth surface dynamics. The TCS Satellite Data will provide two kinds of services: satellite products/services, and Value-added satellite products/services. The satellite products/services are composed of three (EPOSAR, GDM and COMET) well-identified and partly already operational elements for delivering Level 1 products. Such services will be devoted to the generation of SAR interferograms, DTM and ground displacement maps through the exploitation of different advanced EO techniques for InSAR and optical data analysis. The Value-added satellite products/services are composed of 4 elements (EPOSAR, 3D-Def, Mod and COMET) of Level 2 and 3 products. Such services integrate satellite and in situ measurements and observations to retrieve information on source mechanism, such as the geometry (spatial location, depth, volume changes) and the physical parameters of the deformation sources, through the exploitation of modelling approaches. The TCS Satellite Data will provide products in two different processing and delivery modes: 1- surveillance mode - routinely product generation; 2- on demand mode - product generation performed on demand by the user. Concerning the surveillance mode, the goal is providing continuous satellite measurements in areas of particular interest from a geophysical perspective (supersites). The objective is the detection of displacement patterns changing along time and their geophysical explanation. This is a valid approach for inter-seismic movements and volcanic unrest, post-seismic and post

  12. Satellite battery testing status

    NASA Technical Reports Server (NTRS)

    Haag, R.; Hall, S.

    1986-01-01

    Because of the large numbers of satellite cells currently being tested and anticipated at the Naval Weapons Support Center (NAVWPNSUPPCEN) Crane, Indiana, satellite cell testing is being integrated into the Battery Test Automation Project (BTAP). The BTAP, designed to meet the growing needs for battery testing at the NAVWPNSUPPCEN Crane, will consist of several Automated Test Stations (ATSs) which monitor batteries under test. Each ATS will interface with an Automation Network Controller (ANC) which will collect test data for reduction.

  13. Solar Power Satellites

    NASA Technical Reports Server (NTRS)

    Kraft, C. C., Jr.

    1977-01-01

    A satellite based energy concept is described, including the advantages of the basic concept, system characteristics, cost, and environmental considerations. An outline of a plan for the further evaluation and implementation of the system is given. It is concluded that the satellite concept is competitive with other advanced power generation systems when a variety of factors are considered, including technical feasibility, cost, safety, natural resources, environment, baseload capability, location flexibility, land use, and existing industrial base for implementation.

  14. Satellite Applications for Public Service: Project Summaries.

    ERIC Educational Resources Information Center

    Lauffer, Sandra; And Others

    Summaries of 18 different projects involving the use of satellite communications are presented in this report, including PEACESAT Education and Communication Experiments, USP Network Satellite Communication Project, Project Satellite, Satellite Instructional Television Experiment (SITE), Appalachian Education Satellite Program, Alaska Education…

  15. Direct Broadcasting Satellites in Japan.

    ERIC Educational Resources Information Center

    Maeda, Jiro

    The development and use of broadcasting satellites in Japan are discussed in this paper. The paper describes the medium-scale experimental broadcasting satellite, YURI, launched by NASA in 1978, and reports that experiments with YURI in the areas of basic technologies in the broadcasting satellite system, experiments on satellite control…

  16. Satellite Technologies in the Classroom.

    ERIC Educational Resources Information Center

    Portz, Stephen M.

    1999-01-01

    Focuses on ways of using satellite imagery obtained from the Internet, to enhance classroom learning. Discusses satellite deployment; classroom applications, including infrared imagery, high-resolution photography, and global positioning satellites; and use of satellite data for hands-on activities, including cartography, city and community…

  17. Satellite Communications for ATM

    NASA Technical Reports Server (NTRS)

    Shamma, Mohammed A.

    2003-01-01

    This presentation is an overview on Satellite Communication for the Aeronautical Telecommunication Management (ATM) research. Satellite Communications are being considered by the FAA and NASA as a possible alternative to the present and future ground systems supporting Air Traffic Communications. The international Civil Aviation Organization (ICAO) have in place Standards and Recommended Practices (SARPS) for the Aeronautical Mobile Satellite Services (AMSS) which is mainly derived from the pre-existing Inmarsat service that has been in service since the 1980s. The Working Group A of the Aeronautical Mobile Communication Panel of ICAO has also been investigating SARPS for what is called the Next Generation Satellite Service (NGSS) which conforms less to the Inmarsat based architecture and explores wider options in terms of satellite architectures. Several designs are being proposed by Firms such as Boeing, ESA, NASA that are geared toward full or secondary usage of satellite communications for ATM. Satellite communications for ATM can serve several purposes ranging from primary usage where ground services would play a minimal backup role, to an integrated solution where it will be used to cover services, or areas that are less likely to be supported by the proposed and existing ground infrastructure. Such Integrated roles can include usage of satellite communications for oceanic and remote land areas for example. It also can include relieving the capacity of the ground network by providing broadcast based services of Traffic Information Services messages (TIS-B), or Flight Information Services (FIS-B) which can take a significant portion of the ground system capacity. Additionally, satellite communication can play a backup role to support any needs for ground replacement, or additional needed capacity even after the new digital systems are in place. The additional bandwidth that can be provided via satellite communications can also open the door for many new

  18. International communications via satellite

    NASA Astrophysics Data System (ADS)

    McLucas, J. L.

    The evolution of communications satellite systems is traced in terms of technical capabilities and technological advances. The Communications Act of 1962 led to the establishment of INTELSAT on an international basis in 1964. The original 19 signatory nations has grown to over 100, and over 800 ground relay stations have been built. The INTELSAT system comprises spacecraft over the Atlantic, Pacific, and Indian Oceans and handles 2/3 of the world's international electronic communications and all transoceanic television. The 1965 Early Bird satellite had a 240 two-way telephone link capacity and weighed 38 kg, while the Intelsat V satellites, of which there will be nine, have increased the capacity to 20,000 voice circuits and Intelsat VI will double the number by 1993. Increasing demand for satellite communications links is driving the design and development of space platforms for multiple missions of communications, meteorological studies, and on-board switching and data processing in excess of current multiple satellite systems.

  19. Small satellites - An overview

    NASA Astrophysics Data System (ADS)

    Ward, A. K.

    The present review of small satellites examines spacecraft activities in the U.K. and compiles a checklist of advantages and applications for the class. These advantages are illustrated with references to recent small satellite missions and technologies developed to facilitate such launches and projects. Specific programs examined include AMPTE-UKS, Viking, and the UoSAT program, and information is given regarding the Small Explorer program, the RAE Space Technology Research Vehicle, the AEA Argos Program, and space research programs in both Japan and India. Low-cost launches are shown to be available in the form of the Ariane Structure for Auxiliary Payloads, the Pegasus and Delta vehicles, and with the Shuttle Free-flying Getaway Special. Small-satellite technologies that play key roles in their effective implementation are: structure/thermal advances, attitude control systems, on-board communications, and power and data-handling systems.

  20. Brazilian Small Satellites

    NASA Astrophysics Data System (ADS)

    Carvalho, Himilcon

    Brazilian experience with micro scientific satellites began in 1995 with the SACI project that comprised 2 scientific satellites that carried onboard experiments from Brazil, Japan and US. The first one failed after launch (1998) and the second was lost during the second launch attempt of the Brazilian national launcher, VLS, in1999. Started by 1997, the French-Brazilian Microsatellite Project comprised a set of 9 experiments from French and Brazilian scientists. The project was terminated by the French side in 2002. Currently, there are two ongoing science projects, MIRAX (devoted to X-Ray astronomy) and EQUARS (to study the higher atmosphere). These projects include experiments from US, Netherlands, Japan, Canada, and Brazil, with launch scheduled to 2011 or 2012. This paper presents a brief summary of the history of the development of these satellites along with some highlights on the Brazilian Space Program.

  1. Uranus satellites - Surface properties

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Brown, R. H.; Bell, Jeffrey F.

    1991-01-01

    The post-Voyager knowledge of the photometric, colorimetric, spectral, and thermal properties of the Uranian satellites is reviewed, focusing on such fundamental physical properties as albedo, color, and surface texture. While albedo variations of at least a factor of 2 exist, color differences are almost absent (Miranda) or subdued (Oberon). In the case of Titania, the strong opposition effect reported by ground-based observers was confirmed by Voyager. Voyager did not observe the opposition parts of the phase curves of the other satellites. Voyager thermal observations of Ariel and Miranda suggest that both have highly porous regoliths, thermophysically similar to those of Jupiter's icy satellites. At the time of the flyby (south pole facing the sun), maximum surface temperatures reached or exceeded 85 K, but nighttime polar temperatures are predicted to drop to 20 to 30 K because each pole spends about 40 yr in darkness. Ground-based spectroscopy identified water ice as an important surface constituent.

  2. Satellite failures revisited

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2012-12-01

    In January 1994, the two geostationary satellites known as Anik-E1 and Anik-E2, operated by Telesat Canada, failed one after the other within 9 hours, leaving many northern Canadian communities without television and data services. The outage, which shut down much of the country's broadcast television for hours and cost Telesat Canada more than $15 million, generated significant media attention. Lam et al. used publicly available records to revisit the event; they looked at failure details, media coverage, recovery effort, and cost. They also used satellite and ground data to determine the precise causes of those satellite failures. The researchers traced the entire space weather event from conditions on the Sun through the interplanetary medium to the particle environment in geostationary orbit.

  3. Artificial gravity experiment satellites

    NASA Astrophysics Data System (ADS)

    Harada, Tadashi

    1992-07-01

    An overview of the conceptual study of an artificial gravity experiment satellite based on the assumption of a launch by the H-2 launch vehicle with a target launch date in the Year 2000 is presented. While many satellites provided with artificial gravity have been reported in relation to a manned Mars exploration spacecraft mission, the review has been conducted on missions and test subjects only for experimental purposes. Mission requirements were determined based on the results of reviews on the mission, test subjects, and model missions. The system baseline and development plan were based on the results of a study on conceptual structure and scale of the system, including measures to generate artificial gravity. Approximate scale of the system and arm length, mission orbit, visibility of the operation orbit from ground stations in Japan, and satellite attitude on the mission orbit are outlined.

  4. Satellite sale update

    NASA Astrophysics Data System (ADS)

    Richman, Barbara T.

    A senior Department of Commerce official whose connections with the Communications Satellite Corp. (Comsat) regarding the proposed sale of the weather and land satellites (Eos, March 22, 1983, p. 113) have been the subject of congressional inquiry has resigned. Comsat is considered the frontrunner of those looking to purchase the satellites.Guy W. Fiske, Deputy Secretary of Commerce, submitted his letter of resignation on May 10; the resignation became effective May 14. He had been scheduled to testify to two House Science and Technology subcommittees this month on the nature, extent, and propriety of his relationship with Comsat. As Eos went to press, it was unclear whether Fiske would still be asked to testify.

  5. ESA's satellite communications programme

    NASA Astrophysics Data System (ADS)

    Bartholome, P.

    1985-02-01

    The developmental history, current status, and future plans of the ESA satellite-communications programs are discussed in a general survey and illustrated with network diagrams and maps. Consideration is given to the parallel development of national and European direct-broadcast systems and telecommunications networks, the position of the European space and electronics industries in the growing world market, the impact of technological improvements (both in satellite systems and in ground-based networks), and the technological and commercial advantages of integrated space-terrestrial networks. The needs for a European definition of the precise national and international roles of satellite communications, for maximum speed in implementing such decisions (before the technology becomes obsolete), and for increased cooperation and standardization to assure European equipment manufacturers a reasonable share of the market are stressed.

  6. Satellites For Sale

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Astronaut Dale A. Gardner, having just completed the major portion of his second extravehicular activity (EVA) period in three days, holds up a 'For Sale' sign refering to the two satellites, Palapa B-2 and Westar 6 that they retrieved from orbit after their Payload Assist Modules (PAM) failed to fire. Astronaut Joseph P. Allen IV, who also participated in the two EVAs, is reflected in Gardner's helmet visor. A portion of each of two recovered satellites is in the lower right corner, with Westar 6 nearer Discovery's aft.

  7. Satellite communications system 'Tyulpan'

    NASA Astrophysics Data System (ADS)

    Tchuyan, R. K.; Tarasov, E. V.; Belousov, A. P.; Balyk, V. M.; Kovtunenko, V. M.; Morozov, V. A.; Andreev, V. A.; v'yunenko, K. A.

    1993-10-01

    A concept of the satellite communication system called 'Tyulpan' (because or its tulip-resembling shape) is considered. This conception envisages the use of six satellites-retranslators installed on high-latitude elliptic orbits. Such a system can provide the communication for mean- and high-latitude region of Europe, Asia, and America. For the communication, super small ground stations of 0.4 m in diameter can be used. In the development of system conception, the already existing technical solutions and possibility of conversion or existing installations of military destination were taken into account. Therefore, the system considered can be realized at the earliest possible date.

  8. Mexico's first domestic satellite

    NASA Astrophysics Data System (ADS)

    Sanchez-Ruiz, M. E.; Elbert, B. R.

    The principal features of the Morelos communications satellite program, providing Mexico with C-band and Ku-band TV and telephone services beginning in 1985, are reviewed. Two satellites, modified versions of the Hughes HS-376 dual-spin bus, will be launched by STS and controlled from a tracking, telemetery, and command station near Mexico City; the 184-station ground network currently operating with Intelsat-IV will be expanded to about 1000 C-band stations (plus numerous small Ku-band receivers) by 1990. The spacecraft design, communications-subsystem performance, repeater equipment, antennas, and coverage pattern are presented in tables, drawings, diagrams, photographs and maps and discussed.

  9. Satellite Laser Ranging operations

    NASA Technical Reports Server (NTRS)

    Pearlman, Michael R.

    1994-01-01

    Satellite Laser Ranging (SLR) is currently providing precision orbit determination for measurements of: 1) Ocean surface topography from satellite borne radar altimetry, 2) Spatial and temporal variations of the gravity field, 3) Earth and ocean tides, 4) Plate tectonic and regional deformation, 5) Post-glacial uplift and subsidence, 6) Variations in the Earth's center-of-mass, and 7) Variations in Earth rotation. SLR also supports specialized programs in time transfer and classical geodetic positioning, and will soon provide precision ranging to support experiments in relativity.

  10. Satellite oceanography - The instruments

    NASA Technical Reports Server (NTRS)

    Stewart, R. H.

    1981-01-01

    It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.

  11. Oceanography from satellites

    NASA Technical Reports Server (NTRS)

    Wilson, W. S.

    1981-01-01

    It is pointed out that oceanographers have benefited from the space program mainly through the increased efficiency it has brought to ship operations. For example, the Transit navigation system has enabled oceanographers to compile detailed maps of sea-floor properties and to more accurately locate moored subsurface instrumentation. General descriptions are given of instruments used in satellite observations (altimeter, color scanner, infrared radiometer, microwave radiometer, scatterometer, synthetic aperture radar). It is pointed out that because of the large volume of data that satellite instruments generate, the development of algorithms for converting the data into a form expressed in geophysical units has become especially important.

  12. Declassified intelligence satellite photographs

    USGS Publications Warehouse

    U.S. Geological Survey

    1998-01-01

    Recently declassified photographs from spy satellites are an important addition to the record of the Earth?s land surface held by the U.S. Geological Survey (USGS). More than 800,000 high-resolution photos taken between 1959 through 1972 were made available by Executive Order of the President. The collection is held at the USGS EROS Data Center, near Sioux Falls, S. Dak., and are offered for public sale. For some purposes in earth science studies, these photos extend the record of changes in the land surface another decade back in time from the advent of the Landsat earth-observing satellite program.

  13. Public service satellite communications

    NASA Technical Reports Server (NTRS)

    Wolff, E. A.

    1978-01-01

    It is suggested that the high effective isotropic radiated power provided by high-power satellite transmitters and high-gain antennas could be used in conjunction with economical ground receivers to furnish public services in remote areas of the U.S. Applications to health care, education and public safety are mentioned. A system concept involving a communications satellite operating in the Ku-band (12-GHz down, 14-GHz up) and either 100/30 watt stationary earth terminals with 1-1.8 m antennas or mobile terminals with omnidirectional antennas is presented.

  14. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1972-01-01

    Satellite altitude determination uncertainties will be discussed from the standpoint of the GEOS-C satellite, from the longer range viewpoint afforded by the Geopause concept. Data are focused on methods for short-arc tracking which are essentially geometric in nature. One uses combinations of lasers and collocated cameras. The other method relies only on lasers, using three or more to obtain the position fix. Two typical locales are looked at, the Caribbean area, and a region associated with tracking sites at Goddard, Bermuda and Canada which encompasses a portion of the Gulf Stream in which meanders develop.

  15. Numerical simulation of satellite-ring interactions - Resonances and satellite-ring torques

    NASA Technical Reports Server (NTRS)

    Brophy, Thomas G.; Esposito, Larry W.; Stewart, Glen R.; Rosen, Paul A.

    1992-01-01

    The Krook kinetic equation for planetary rings is numerically solved in two spatial dimensions and in time, with (1) interparticle collisions and (2) satellite-forcing, but (3) without self-gravity, for the case of a flattened planetary ring that undergoes gravitational perturbation by a nearby satellite. It is noted that the amplitude of wakes is limited by purely kinematic effects, even in the absence of collisions. Attention is given to the results of a simulation of an inner Lindblad-resonance location, as the distribution approaches steady state; these simulations do not show an increase in velocity dispersion in the resonance zone, obviating a net torque.

  16. Tracking the GLOMR satellite

    NASA Technical Reports Server (NTRS)

    Reiss, Keith W.; Oneil, Jason C.

    1987-01-01

    The task of day-to-day low orbiting satellite tracking utilizing the NAVSPASUR orbital elements is discussed and methods for improving pass time predictions are presented. Estimates are needed for preprogramming of satellite-initiated communications scheduling which requires an accuracy of approximately 30 seconds. This can be achieved by removing the variance associated with the NAVSPASUR D sub 2 (decay) term. Finally, the shock evidenced in GLOMR's orbit on February 7, 1986 is documented and attributed to a severe solar storm with immediately enhanced drag. GLOMR's life expectancy in orbit is now estimated to have dropped approximately 17% by the end of orbit in early February, 1987.

  17. The American Satellite Company (ASC) satellite deployed from payload bay

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The American Satellite Company (ASC) communications satellite is deployed from the payload bay of the Shuttle Discovery. A portion of the cloudy surface of the earth can be seen to the left of the frame.

  18. Mobile satellite ranging

    NASA Technical Reports Server (NTRS)

    Silverberg, E. C.

    1978-01-01

    A brief review of the constraints which have limited satellite ranging hardware and an outline of the steps which are underway to improve the status of the equipment in this area are given. In addition, some suggestions are presented for the utilization of newer instruments and for possible future research and development work in this area.

  19. Satellite Town Meeting.

    ERIC Educational Resources Information Center

    Department of Education, Washington, DC.

    On the third Tuesday of each month, U.S. Secretary of Education, Richard W. Riley, and Deputy Secretary, Madeleine M. Kunin, host the Satellite Town Meeting--a live, interactive teleconference where renowned national experts, local educators, and community leaders share ideas on how to improve schools and reach the National Educational Goals. It…

  20. Small satellite radiometric measurements

    SciTech Connect

    Weber, P.G.

    1991-01-01

    A critical need for the Mission to Planet Earth is to provide continuous, well-calibrated radiometric data for the radiation budget. This paper describes a new, compact, flexible radiometer which will provide both spectrally integrated data and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted vehicles (RPVs). 12 refs., 2 figs.

  1. Perception via satellite

    USGS Publications Warehouse

    Robinove, Charles J.

    1970-01-01

    The earth resources observation satellite (EROS) program in the Department of the Interior is intended to gather and use data from satellites and aircraft on natural and man-made features of the earth's surface. Earth resources technology satellite will provide the EROS program with data for use in dealing with natural resource problems and understanding the interaction between man and the environment. Applications will include studies of tectonic features, hydrologic problems, location of fish schools, determination of the conditions of range land, mapping land use for urban planning, studies of erosion and change along coastlines and major streams, and inventories of land use and land forms. In addition, the ERTS data may be used for detecting forest and crop diseases and inventorying crops. The ERTS satellite will be in a polar, sun-synchronous orbit so that each point on the earth's surface will be sensed every 17 to 20 days, at the same time of day. Multispectral photography is being investigated for its usefulness in hydrology. Side-looking airborne radar has not yet been widely used in hydrologic studies, although it is an excellent tool for all-weather, day or night, coverage of large areas. Other techniques being investigated include passive microwave radiometry, ultraviolet and visible stimulated luminescence, and absorption spectroscopy.

  2. Virophages or satellite viruses?

    PubMed

    Krupovic, Mart; Cvirkaite-Krupovic, Virginija

    2011-11-01

    It has been argued that the smaller viruses associated with giant DNA viruses are a new biological entity. However, Mart Krupovic and Virginija Cvirkaite-Krupovic argue here that these smaller viruses should be classified with the satellite viruses. PMID:22016897

  3. Building Satellites is Easier

    NASA Technical Reports Server (NTRS)

    Marsh, Phyllis Nimmo

    1996-01-01

    'Building Satellites' is a story about Jim Marsh's recovery from a severe head injury told by his wife Phyllis from the moment she learned of its happening, through the ups and downs of a lengthy rehabilitation, until his return to work and daily living. It continues on, however, and narrates his battle with the more insidious Grave's disease. Told in the first person, 'Building Satellites' vividly portrays Phyllis's thoughts and feelings throughout this experience with scrupulous honestly. This is a story worth reading for many reasons. First of all, Jim was an accomplished scientist, respected by his colleagues both in this country and abroad. Secondly, it narrates the many stages of his recovery from head injury with detailed readable accuracy; it informs us as well as inspires. Finally, 'Building Satellites" also tells us the story of Phyllis Marsh's remarkable creative response to this crisis. It narrates her personal experiences as she progresses through the strange and somewhat bizarre world of medicine and rehabilitation, guided by a few basic beliefs, which she learned as a child in Iowa, that provided her with the strength to endure. 'Building Satellites' seems to reaffirm our unconscious, but settled conviction, that when confornted overnight with adversity, we are somehow given the means for coping, supported by our basic beliefs, strengthened by family and friends, and eventually learning to accept any outcome.

  4. Experimental Satellite Quantum Communications

    NASA Astrophysics Data System (ADS)

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-01

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER =4.6 % for a total link duration of 85 s. The mean photon number per pulse μsat leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers.

  5. Learning Through Satellite Broadcasting

    ERIC Educational Resources Information Center

    Krishnamoorthy, P. V.

    1975-01-01

    SITE is an experimental project which would provide vital inputs in designing and executing a satellite-based instructional television system, particularly in rural areas, to stimulate national development in India with important managerial, economic, technological, and social implications. (Author/BP)

  6. Advances in satellite oceanography

    NASA Technical Reports Server (NTRS)

    Brown, O. B.; Cheney, R. E.

    1983-01-01

    Technical advances and recent applications of active and passive satellite remote sensing techniques to the study of oceanic processes are summarized. The general themes include infrared and visible radiometry, active and passive microwave sensors, and buoy location systems. The surface parameters of sea surface temperature, windstream, sea state, altimetry, color, and ice are treated as applicable under each of the general methods.

  7. Retroreflector spherical satellite

    NASA Astrophysics Data System (ADS)

    Akentyev, A. S.; Vasiliev, V. P.; Sadovnikov, M. A.; Sokolov, A. L.; Shargorodskiy, V. D.

    2015-10-01

    Specific features of spherical retroreflector arrays for high-precision laser ranging are considered, and errors in distance measurements are analyzed. A version of a glass retroreflector satellite with a submillimeter "target error" is proposed. Its corner cube reflectors are located in depressions to reduce the working angular aperture, and their faces have a dielectric interference coating.

  8. Which satellites were used?

    Atmospheric Science Data Center

    2014-12-08

    ... (Scanner and NonScanner) were used. The NASA Goddard Space Flight Center built the Earth Radiation Budget Satellite (ERBS) on which the first ERBE instruments were launched by the Space Shuttle Challenger in 1984. ERBE instruments were also launched on two ...

  9. Domestic Communications Satellites.

    ERIC Educational Resources Information Center

    Network Project Notebook, 1972

    1972-01-01

    The June, 1972 Federal Communications Commission's (FCC) decision allowed an "open skies" policy in regard to domestic communication satellites and raised Liberal opposition to a situation where exclusive and unchecked communications power is now in the hands of private entrepreneurs, primarily the big Defense Department oriented aerospace…

  10. Experimental Satellite Quantum Communications.

    PubMed

    Vallone, Giuseppe; Bacco, Davide; Dequal, Daniele; Gaiarin, Simone; Luceri, Vincenza; Bianco, Giuseppe; Villoresi, Paolo

    2015-07-24

    Quantum communication (QC), namely, the faithful transmission of generic quantum states, is a key ingredient of quantum information science. Here we demonstrate QC with polarization encoding from space to ground by exploiting satellite corner cube retroreflectors as quantum transmitters in orbit and the Matera Laser Ranging Observatory of the Italian Space Agency in Matera, Italy, as a quantum receiver. The quantum bit error ratio (QBER) has been kept steadily low to a level suitable for several quantum information protocols, as the violation of Bell inequalities or quantum key distribution (QKD). Indeed, by taking data from different satellites, we demonstrate an average value of QBER=4.6% for a total link duration of 85 s. The mean photon number per pulse μ_{sat} leaving the satellites was estimated to be of the order of one. In addition, we propose a fully operational satellite QKD system by exploiting our communication scheme with orbiting retroreflectors equipped with a modulator, a very compact payload. Our scheme paves the way toward the implementation of a QC worldwide network leveraging existing receivers. PMID:26252672

  11. Data distribution satellite

    NASA Technical Reports Server (NTRS)

    Price, Kent M.; Jorasch, Ronald E.; Wiskerchen, Michael J.

    1991-01-01

    A description is given of a data distribution satellite (DDS) system. The DDS would operate in conjunction with the tracking and data relay satellite system to give ground-based users real time, two-way access to instruments in space and space-gathered data. The scope of work includes the following: (1) user requirements are derived; (2) communication scenarios are synthesized; (3) system design constraints and projected technology availability are identified; (4) DDS communications payload configuration is derived, and the satellite is designed; (5) requirements for earth terminals and network control are given; (6) system costs are estimated, both life cycle costs and user fees; and (7) technology developments are recommended, and a technology development plan is given. The most important results obtained are as follows: (1) a satellite designed for launch in 2007 is feasible and has 10 Gb/s capacity, 5.5 kW power, and 2000 kg mass; (2) DDS features include on-board baseband switching, use of Ku- and Ka-bands, multiple optical intersatellite links; and (3) system user costs are competitive with projected terrestrial communication costs.

  12. On satellite constellation selection

    SciTech Connect

    Canavan, G.H.

    1991-05-01

    Analytical estimates can be used to produce and discuss optimal constellations. They are in close agreement with phase-space estimates and exact solutions. They suggest that distributions of inclined orbits could reduce satellite numbers by factors of 2--3 while improving uniformity. 4 refs., 2 figs.

  13. THE ONE ROOM SATELLITE.

    ERIC Educational Resources Information Center

    DREYFUS, LEE S.

    A WISCONSIN HIGH SCHOOL FRENCH CLASS AND A GROUP OF STUDENTS IN AN ENGLISH CALSS AT THE LYCEE HENRI IV OF PARIS, FRANCE, PARTICIPATED IN A COMBINED CLASS SESSION IN THE FIRST INTERNATIONAL TV CLASSROOM EXCHANGE. THE TV SIGNALS WERE EXCHANGED BY MEANS OF THE EARLY BIRD SATELLITE AND PERMITTED THE STUDENTS TO EXCHANGE MESSAGES. DURING THE TELECAST…

  14. Satellite camera image navigation

    NASA Technical Reports Server (NTRS)

    Kamel, Ahmed A. (Inventor); Graul, Donald W. (Inventor); Savides, John (Inventor); Hanson, Charles W. (Inventor)

    1987-01-01

    Pixels within a satellite camera (1, 2) image are precisely located in terms of latitude and longitude on a celestial body, such as the earth, being imaged. A computer (60) on the earth generates models (40, 50) of the satellite's orbit and attitude, respectively. The orbit model (40) is generated from measurements of stars and landmarks taken by the camera (1, 2), and by range data. The orbit model (40) is an expression of the satellite's latitude and longitude at the subsatellite point, and of the altitude of the satellite, as a function of time, using as coefficients (K) the six Keplerian elements at epoch. The attitude model (50) is based upon star measurements taken by each camera (1, 2). The attitude model (50) is a set of expressions for the deviations in a set of mutually orthogonal reference optical axes (x, y, z) as a function of time, for each camera (1, 2). Measured data is fit into the models (40, 50) using a walking least squares fit algorithm. A transformation computer (66 ) transforms pixel coordinates as telemetered by the camera (1, 2) into earth latitude and longitude coordinates, using the orbit and attitude models (40, 50).

  15. Satellite Weather Watch.

    ERIC Educational Resources Information Center

    Summers, R. Joe

    1982-01-01

    Describes an inexpensive (about $1,500) direct-readout ground station for use in secondary school science/mathematics programs. Includes suggested activities including, among others, developing map overlays, operating station equipment, interpreting satellite data, developing weather forecasts, and using microcomputers for data storage, orbit…

  16. Small satellite space operations

    NASA Technical Reports Server (NTRS)

    Reiss, Keith

    1994-01-01

    CTA Space Systems has played a premier role in the development of the 'lightsat' programs of the 80's and 90's. The high costs and development times associated with conventional LEO satellite design, fabrication, launch, and operations continue to motivate the development of new methodologies, techniques, and generally low cost and less stringently regulated satellites. These spacecraft employ low power 'lightsat' communications (versus TDRSS for NASA's LEO's) and typically fly missions with payload/experiment suites that can succeed, for example, without heavily redundant backup systems and large infrastructures of personnel and ground support systems. Such small yet adaptable satellites are also typified by their very short contract-to-launch times (often one to two years). This paper reflects several of the methodologies and perspectives of our successful involvement in these innovative programs and suggests how they might relieve NASA's mounting pressures to reduce the cost of both the spacecraft and their companion mission operations. It focuses on the use of adaptable, sufficiently powerful yet inexpensive PC-based ground systems for wide ranging user terminal (UT) applications and master control facilities for mission operations. These systems proved themselves in successfully controlling more than two dozen USAF, USN, and ARPA satellites at CTA/SS. UT versions have linked with both GEO and LEO satellites and functioned autonomously in relay roles often in remote parts of the world. LEO applications particularly illustrate the efficacy of these concepts since a user can easily mount a lightweight antenna, usually an omni or helix with light duty rotors and PC-based drivers. A few feet of coax connected to a small transceiver module (the size of a small PC) and a serial line to an associated PC establishes a communications link and together with the PC constitute a viable ground station. Applications included geomagnetic mapping; spaceborne solid state

  17. Cibola flight experiment satellite

    NASA Astrophysics Data System (ADS)

    Davies, P.; Liddle, Doug; Paffett, John; Sweeting, Martin; Curiel, A.; Sun, Wei; Eves, Stuart

    2004-11-01

    In order to achieve an "economy of scale" with respect to payload capacity the major trend in telecommunications satellites is for larger and larger platforms. With these large platforms the level of integration between platform and payload is increasing leading to longer delivery schedules. The typical lifecycle for procurement of these large telecommunications satellites is now 3-6 years depending on the level of non-recurring engineering needed. Surrey Satellite Technology Ltd (SSTL) has designed a low-cost platform aimed at telecommunications and navigation applications. SSTL's Geostationary Minisatellite Platform (GMP) is a new entrant addressing the lower end of the market with payloads up to 250kg requiring less than 1.5 kW power. The British National Space Centre through the MOSAIC Small Satellite Initiative supported the development of GMP. The main design goals for GMP are low-cost for the complete mission including launch and operations and a platform allowing flexible payload accommodation. GMP is specifically designed to allow rapid development and deployment with schedules typically between 1 and 2 years from contract signature to flight readiness. GMP achieves these aims by a modular design where the level of integration between the platform and payload is low. The modular design decomposes the satellite into three major components - the propulsion bay, the avionics bay and the payload module. Both the propulsion and avionics bays are reusable, largely unchanged, and independent of the payload configuration. Such a design means that SSTL or a 3rd party manufacturer can manufacture the payload in parallel to the platform with integration taking place quite late in the schedule. In July 2003 SSTL signed a contract for ESA's first Galileo navigation satellite known as GSTBV2/A. The satellite is based on GMP and ESA plan to launch it into a MEO orbit late in 2005. The second flight of GMP is likely to be in 2006 carrying a geostationary payload

  18. LISA satellite formation control

    NASA Astrophysics Data System (ADS)

    Bik, J. J. C. M.; Visser, P. N. A. M.; Jennrich, O.

    The joint ESA-NASA Laser Interferometer Space Antenna (LISA) mission consists of a triangular formation of three satellites aiming at detecting gravitational waves. In linear approximation the LISA satellites describe a circle around a reference point, maintaining a fixed position with respect to each other. The reference point, the center of the triangle, orbits the Sun in a circular orbit, trailing the Earth at twenty degrees. In reality the distance between the satellites will vary by about one to two percent and the angle between the arms of the antenna will vary by about 0.5° over the course of one year for the nominal LISA satellite configuration. For measurement accuracy it is desirable that the pointing offset of the telescopes be kept small. This makes it necessary to actuate the telescopes or to control the formation. It was assumed that the LISA satellites are equipped with six μN engines that would allow to keep the two cubical proof masses within each satellite in almost perfect free fall. It was found that control forces up to about 700 μN are required for maintaining the absolute triangular LISA formation, leading to unacceptable excursions of the proof masses from free fall. However, these forces compensate predominantly very low frequency variations of the arm lengths and angles of the triangle, which are then to be compensated by the telescope actuators. The variations are outside the aimed LISA measurement bandwidth (10 -4-0.1 Hz). In addition, the effect of thruster noise, orbit determination errors and orbit injection errors was examined. The effect of these error sources on the arm lengths and orientation angles between the LISA satellites was assessed both in open loop and in closed loop, where the closed loop was based on a proportional-derivative (PD) controller. It was found that orbit determination errors of the order of a few km in position and a few mm/s in velocity lead to negligible closed loop control forces. In addition, orbit

  19. Attitude stability of spinning satellites

    NASA Technical Reports Server (NTRS)

    Caughey, T. K.

    1980-01-01

    Some problems of attitude stability of spinning satellites are treated in a rigorous manner. With certain restrictions, linearized stability analysis correctly predicts the attitude stability of spinning satellites, even in the critical cases of the Liapunov-Poincare stability theory.

  20. 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...

  1. Meteorological measurements from satellite platforms

    NASA Technical Reports Server (NTRS)

    Suomi, V. E.

    1972-01-01

    Quantitative exploitation of meteorological data from geosynchronous satellites is starting to move from the laboratory to operational practice. Investigations of the data applications portion of the total meteorological satellite system include: (1) tropospheric wind shear and the related severe storm circulations; (2) kinematic properties of the tropical atmosphere as derived from cloud motion vectors; (3) application of a geostationary satellite rake system to measurements of rainfall; and (4) pointing error analysis of geosynchronous satellites.

  2. Telelibrary: Library Services via Satellite.

    ERIC Educational Resources Information Center

    Liu, Rosa

    1979-01-01

    Investigates the provision of library services via satellite, explains briefly the operation and advantages of communication satellites, and discusses the various telecommunications equipment and services which, when coupled with satellite transmission, will enhance library activities. Demand trend projections for telecommunications services…

  3. Mobile satellite service for Canada

    NASA Technical Reports Server (NTRS)

    Sward, David

    1988-01-01

    The Mobile Satellite (MSAT) system and a special program designed to provide interim mobile satellite services (IMSS) during the construction phase of MSAT are described. A mobile satellite system is a key element in extending voice and and data telecommunications to all Canadians.

  4. Irregular Satellites of the Planets

    NASA Technical Reports Server (NTRS)

    Jewitt, David

    2005-01-01

    This proposal is directed towards the observational exploration of the irregular satellite systems of the planets. Primarily we use large-format CCD cameras on the world's largest telescopes, on Mauna Kea, to discover new irregular satellites and then to monitor their positions in order to ascertain their orbital characteristics. Separate observations are taken to determine the physical properties of the irregular satellites. The big picture science objective is to determine how these satellites were captures, and to use the properties of the satellites and their orbits to place constraints on early solar system (including formation) processes. Work in the first year has focussed on a major investigation of the Saturn irregular satellite system. We secured observing time on the Subaru and Gemini 8-m diameter telescopes in December 2004, January, February and March 2005 for the conduct of a deep, wide-area survey. This has resulted in the detection and orbit determination for 12 new satellites to be announced in the next week or two. Additional satellites were lost, temporarily, due to unusually poor weather conditions on Mauna Kea. These objects will be recovered and their orbits published next year. A separate survey of the Uranus irregular satellites was published (Sheppard, Jewitt and Kleyna 2005). Away from the telescope, we have discovered the amazing result that the four giant planets possess similar numbers of irregular satellites. This flies in the face of the standard gas-drag model for satellite capture, since only two of the giant planets are gas giants and the others (Uranus and Neptune) formed by a different process and in the absence of much gas. The constancy of the satellite number (each giant holds approximately 100 irregular satellites measured down to the kilometer scale) is either a coincidence, with different capture mechanisms at different planets giving by chance the same total numbers of irregular satellites, or indicates that the satellites

  5. An aeronautical mobile satellite experiment

    NASA Technical Reports Server (NTRS)

    Jedrey, T. C.; Dessouky, K. I.; Lay, N. E.

    1990-01-01

    The various activities and findings of a NASA/FAA/COMSAT/INMARSAT collaborative aeronautical mobile satellite experiment are detailed. The primary objective of the experiment was to demonstrate and evaluate an advanced digital mobile satellite terminal developed at the Jet Propulsion Laboratory under the NASA Mobile Satellite Program. The experiment was a significant milestone for NASA/JPL, since it was the first test of the mobile terminal in a true mobile satellite environment. The results were also of interest to the general mobile satellite community because of the advanced nature of the technologies employed in the terminal.

  6. The AMSC mobile satellite system

    NASA Technical Reports Server (NTRS)

    Agnew, Carson E.; Bhagat, Jai; Hopper, Edwin A.; Kiesling, John D.; Exner, Michael L.; Melillo, Lawrence; Noreen, Gary K.; Parrott, Billy J.

    1988-01-01

    The American Mobile Satellite Consortium (AMSC) Mobile Satellite Service (MSS) system is described. AMSC will use three multi-beam satellites to provide L-band MSS coverage to the United States, Canada and Mexico. The AMSC MSS system will have several noteworthy features, including a priority assignment processor that will ensure preemptive access to emergency services, a flexible SCPC channel scheme that will support a wide diversity of services, enlarged system capacity through frequency and orbit reuse, and high effective satellite transmitted power. Each AMSC satellite will make use of 14 MHz (bi-directional) of L-band spectrum. The Ku-band will be used for feeder links.

  7. Automated satellite image navigation

    NASA Astrophysics Data System (ADS)

    Bassett, Robert M.

    1992-12-01

    The automated satellite image navigation method (Auto-Avian) developed and tested by Spaulding (1990) at the Naval Postgraduate School is investigated. The Auto-Avian method replaced the manual procedure of selecting Ground Control Points (GCP's) with an autocorrelation process that utilizes the World Vector Shoreline (WVS) provided by the Defense Mapping Agency (DMA) as a string of GCP's to rectify satellite images. The automatic cross-correlation of binary reference (WVS) and search (image) windows eliminated the subjective error associated with the manual selection of GCP's and produced accuracies comparable to the manual method. The scope of Spaulding's (1990) research was expanded. The worldwide application of the Auto-Avian method was demonstrated in three world regions (eastern North Pacific Ocean, eastern North Atlantic Ocean, and Persian Gulf). Using five case studies, the performance of the Auto-Avian method on 'less than optimum' images (i.e., islands, coastlines affected by lateral distortion and/or cloud cover) was investigated.

  8. New Martian satellite search

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The approach pictures taken by the Viking 1 and Viking 2 spacecrafts two days before their Mars orbital insertion maneuvers were analyzed in order to search for new satellites within the orbit of Phobos. To accomplish this task, search procedure and analysis strategy were formulated, developed and executed using the substantial image processing capabilities of the Image Processing Laboratory at the Jet Propulsion Laboratory. The development of these new search capabilities should prove to be valuable to NASA in processing of image data obtained from other spacecraft missions. The result of applying the search procedures to the Viking approach pictures was as follows: no new satellites of comparable size (approx. 20 km) and brightness to Phobos or Demios were detected within the orbit of Phobos.

  9. Binary satellite galaxies

    NASA Astrophysics Data System (ADS)

    Evslin, Jarah

    2014-05-01

    Suggestions have appeared in the literature that the following four pairs of Milky Way and Andromeda satellite galaxies are gravitationally bound: Draco and Ursa Minor, Leo IV and V, Andromeda I and III, and NGC 147 and 185. Assuming that a given pair is gravitationally bound, the Virial theorem provides a crude estimate of its total mass and so its instantaneous tidal radius. In the case of each pair except for Leo IV and Leo V, the estimated tidal radius is inferior to the separation between the two satellites, suggesting that these pairs are not currently gravitationally bound. Their proximities may be explained if each pair condensed from the remnants of a formerly gravitationally bound structure, but such a scenario is in tension with the absence of older pairs with a wider separation.

  10. Satellite orbit determination

    NASA Technical Reports Server (NTRS)

    Jordan, J. F.; Boggs, D. H.; Born, G. H.; Christensen, E. J.; Ferrari, A. J.; Green, D. W.; Hylkema, R. K.; Mohan, S. N.; Reinbold, S. J.; Sievers, G. L.

    1973-01-01

    A historic account of the activities of the Satellite OD Group during the MM'71 mission is given along with an assessment of the accuracy of the determined orbit of the Mariner 9 spacecraft. Preflight study results are reviewed, and the major error sources described. Tracking and data fitting strategy actually used in the real time operations is itemized, and Deep Space Network data available for orbit fitting during the mission and the auxiliary information used by the navigation team are described. A detailed orbit fitting history of the first four revolutions of the satellite orbit of Mariner 9 is presented, with emphasis on the convergence problems and the delivered solution for the first orbit trim maneuver. Also included are a solution accuracy summary, the history of the spacecraft orbit osculating elements, the results of verifying the radio solutions with TV imaging data, and a summary of the normal points generated for the relativity experiment.

  11. Declassified Intelligence Satellite Photographs

    USGS Publications Warehouse

    U.S. Geological Survey

    2008-01-01

    Declassified photographs from U.S. intelligence satellites provide an important worldwide addition to the public record of the Earth's land surface. This imagery was released to the National Archives and Records Administration (NARA) and the U.S. Geological Survey (USGS) in accordance with Executive Order 12951 on February 23, 1995. The NARA has the original declassified film and a viewing copy. The USGS has another copy of the film to complement the Landsat archive. The declassified collection involves more than 990,000 photographs taken from 1959 through 1980 and was released on two separate occasions: February 1995 (Declass 1) and September 2002 (Declass 2). The USGS copy is maintained by the Earth Resources Observation and Science (EROS) Center, near Sioux Falls, South Dakota. Both the NARA and EROS provide public access to this unique collection that extends the record of land-surface change back another decade from the advent of the Landsat program that began satellite operations in 1972.

  12. Ice reconnaissance by satellite

    NASA Technical Reports Server (NTRS)

    Gloersen, P.; Strome, W. M.

    1976-01-01

    The paper describes the significant milestones in the use of satellites for snow and ice monitoring. The feasibility of such monitoring was demonstrated by the Tiros 2 satellite in 1961. Nimbus 1 showed that breaks in the sea ice can be easily monitored during continuous nighttime conditions; Nimbus 3 showed the practicality of delineating regions of active melting of ice and snow in temperate areas. Landsat data have been found to be particularly useful for monitoring and studying glaciers and their attendant surface features. Ice concentration can be determined with reasonable accuracy from a sequence of electronically scanned microwave radiomenter images made aboard Nimbus 5. In the future we can expect improved sensors and spacecraft systems with longer operating lives.

  13. TOPEX satellite option study

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The basic design of the fleet satellite communication spacecraft (FLTSATCOM) can easily accommodate any of the three payload options for the ocean dynamic topography experiment (TOPEX). The principal mission requirements as well as the payload accommodations and communications systems needed for launching this payload are reviewed. The existing FLTSATCOM satellite design is identified and the approaches for the proposed propulsion system are described in addition to subsystems for mechanical; power; attitude and velocity control; and telemetry, tracking and control are described. The compatability of FLTSATCOM with the launch vehicle is examined and its capabilities vs TOPEX requirements are summarized. Undetermined changes needed to meet data storage, thermal control, and area to mass ratio requirements are discussed. Cost estimates are included for budgetary and planning purposes. The availability of the described design is assessed based on the continuing production of FLTSATCOM spacecraft during the schedule span planned for TOPEX.

  14. LDEF Satellite Radiation Analyses

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    1996-01-01

    This report covers work performed by Science Applications International Corporation (SAIC) under contract NAS8-39386 from the NASA Marshall Space Flight Center entitled LDEF Satellite Radiation Analyses. The basic objective of the study was to evaluate the accuracy of present models and computational methods for defining the ionizing radiation environment for spacecraft in Low Earth Orbit (LEO) by making comparisons with radiation measurements made on the Long Duration Exposure Facility (LDEF) satellite, which was recovered after almost six years in space. The emphasis of the work here is on predictions and comparisons with LDEF measurements of induced radioactivity and Linear Energy Transfer (LET) measurements. These model/data comparisons have been used to evaluate the accuracy of current models for predicting the flux and directionality of trapped protons for LEO missions.

  15. Satellite retrieval system

    NASA Technical Reports Server (NTRS)

    Pruett, E. C.; Robertson, K. B.; Loughead, T. E. (Inventor)

    1983-01-01

    A satellite retrieval system with first and second pairs of coacting parallel bars are separately mounted in spaced parallel planes on the front of a spacecraft. The bars of one pair are at right angles to bars of the other pair, and together the two pairs of bars effect a variable aperture adapted to close around a rod extending from a second spacecraft to effect the capture of the latter.

  16. Satellite servicing economic study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Previous studies have shown that satellite servicing is cost effective; however, all of these studies were of different formats, dollar year, learning rates, availability, etc. Therefore, it was difficult to correlate any useful trends from these studies. The reviewed study was initiated to correlate the economic data into a common data base, using a common set of assumptions. A selected set of existed funded programs was then analyzed to provide an independent analysis of the servicing options and potential economic benefits.

  17. Satellite servicing economic study

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Previous studies have shown that satellite servicing is cost effective; however, all of these studies were of different formats, dollar year, learning rates, availability, etc. Threfore, it was difficult to correlate any useful trends from these studies. The reviewed study was initiated to correlate the economic data into a common data base, using a common set of assumptions. A selected set of existed funded programs was then analyzed to provide an independent analysis of the servicing options and potential economic benefits.

  18. Satellite freeze forecast system

    NASA Technical Reports Server (NTRS)

    Martsolf, J. D. (Principal Investigator)

    1983-01-01

    Provisions for back-up operations for the satellite freeze forecast system are discussed including software and hardware maintenance and DS/1000-1V linkage; troubleshooting; and digitized radar usage. The documentation developed; dissemination of data products via television and the IFAS computer network; data base management; predictive models; the installation of and progress towards the operational status of key stations; and digital data acquisition are also considered. The d addition of dew point temperature into the P-model is outlined.

  19. Recovery of spinning satellites

    NASA Technical Reports Server (NTRS)

    Coppey, J. M.; Mahaffey, W. R.

    1977-01-01

    The behavior of a space tug and a spinning satellite in a coupled configuration was simulated and analyzed. A docking concept was developed to investigate the requirements pertaining to the design of a docking interface. Sensing techniques and control requirements for the chase vehicle were studied to assess the feasibility of an automatic docking. The effects of nutation dampers and liquid propellant slosh motion upon the docking transient were investigated.

  20. Pupil projects involving satellites

    NASA Astrophysics Data System (ADS)

    Perry, G.

    1984-05-01

    The techniques used by pupils at Kettering School, UK, to monitor the USSR space program (using NASA-supplied NORAD radar data and radio transmissions from the spacecraft) are reviewed, and some results are summarized. The main methods used by the pupils include plotting plane spacings, determining orbital periods, and monitoring transmissions from meteorological and navigation satellites and cosmonaut voice communications. The programs covered are briefly characterized, and a glossary of terms is provided.

  1. ASPEC: Solar power satellite

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The solar power satellite (SPS) will provide a clean, reliable source of energy for large-scale consumption. The system will use satellites in geostationary orbits around the Earth to capture the Sun's energy. The intercepted sunlight will be converted to laser beam energy that can be transmitted to the Earth's surface. Ground systems on the Earth will convert the transmissions from space into electric power. The preliminary design for the SPS consists of one satellite in orbit around the Earth transmitting energy to a single ground station. The SPS design uses multilayer solar cell technology arranged on a 20 km squared planar array to intercept sunlight and convert it to an electric voltage. Power conditioning devices then send the electricity to a laser, which transmits the power to the surface of the Earth. A ground station will convert the beam into electricity. Typically, a single SPS will supply 5 GW of power to the ground station. Due to the large mass of the SPS, about 41 million kg, construction in space is needed in order to keep the structural mass low. The orbit configuration for this design is to operate a single satellite in geosynchronous orbit (GEO). The GEO allows the system to be positioned above a single receiving station and remain in sunlight 99 percent of the time. Construction will take place in low Earth orbit (LEO); array sections, 20 in total, will be sailed on solar wind out to the GEO location in 150 days. These individual transportation sections are referred to as solar sailing array panels (SSAP's). The primary truss elements used to support the array are composed of composite tubular members in a pentahedral arrangement. Smart segments consisting of passive and active damping devices will increase the control of dynamic SPS modes.

  2. Satellite Hyperspectral Imaging Simulation

    NASA Technical Reports Server (NTRS)

    Zanoni, Vicki; Stanley, Tom; Blonski, Slawomir; Cao, Changyong; Gasser, Jerry; Ryan, Robert; Zanoni, Vicki; Stanley, Tom

    1999-01-01

    Simulations of generic pushbroom satellite hyperspetral sensors have been performed to evaluate the potential performance and validation techniques for satellite systems such as COIS (NEMO), Warfighter-1 (OrbView-4), and Hyperion (EO-1). The simulaitons start with a generation of synthetic scenes form material maps of studied terrain. Scene-reflected radiance is corrected for atmospheric effects and convolved with sensor spectral response uwing MODTRAN 4 radiance and transmission calculations. Scene images are further convolved with point spread functions derived from Optical Transfer Functions (OTF's) of the sensor system. Photon noise and detector/electronics noise are added to the simulated images, which are also finally quantized to the sensor bit resolution. Studied scenes include bridges and straight roads used for evaluation of sensor spatial resolution, as well as fields of minerals, vegetation, and manmade materials used for evaluation of sensor radiometric response and sensitivity. The scenes are simulated with various seasons and weather conditions. Signal-to-noise ratos and expected performance are estimated for typica satellite system specifications and are discussed for all the scenes.

  3. Satellite Hyperspectral Imaging Simulation

    NASA Technical Reports Server (NTRS)

    Zanoni, Vicki; Stanley, Tom; Blonski, Slawomir; Cao, Changyong; Gasser, Jerry; Ryan, Robert

    1999-01-01

    Simulation of generic pushbroom satellite hyperspectral sensors have been performed to evaluate the potential performance and validation techniques for satellite systems such as COIS(NEMO), Warfighter-1(OrbView-4) and Hyperion(EO-1). The simulations start with a generation of synthetic scenes from material maps of studied terrain. Scene-reflected radiance is corrected for atmospheric effects and convolved with sensor spectral response using MODTRAN 4 radiance and transmissions calculations. Scene images are further convolved with point spread functions derived from Optical Transfer Functions (OTF's) of the sensor system. Photon noise and etectorr/electronics noise are added to the simulated images, which are also finally quantized to the sensor bit resolution. Studied scenes include bridges and straight roads used for evaluation of sensor spatial resolution, as well as fields of minerals, vegetation and manmade materials used for evaluation of sensor radiometric response and sensitivity. The scenes are simulated with various seasons and weather conditions. Signal-to-noise ratios and expected performance are estimated for typical satellite system specifications and are discussed for all the scenes.

  4. Heart Monitoring By Satellite

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The ambulance antenna shown is a specially designed system that allows satellite-relayed two-way communications between a moving emergency vehicle and a hospital emergency room. It is a key component of a demonstration program aimed at showing how emergency medical service can be provided to people in remote rural areas. Satellite communication permits immediate, hospital- guided treatment of heart attacks or other emergencies by ambulance personnel, saving vital time when the scene of the emergency is remote from the hospital. If widely adopted, the system could save tens of thousands of lives annually in the U.S. alone, medical experts say. The problem in conventional communication with rural areas is the fact that radio signals travel in line of sight. They may be blocked by tall buildings, hills and mountains, or even by the curvature of the Earth, so signal range is sharply limited. Microwave relay towers could solve the problem, but a complete network of repeater towers would be extremely expensive. The satellite provides an obstruction-free relay station in space.

  5. NORAD satellite tracking

    NASA Technical Reports Server (NTRS)

    Liu, Joseph J. F.

    1987-01-01

    NORAD routinely tracks about 6000 orbiting objects. During the last 30 days of orbital time, prior to reentry, special perturbations are used in the orbital update procedure. Besides routine orbit determination, NORAD does special tasks such as predicting satellite orbit conjunctions within 20 km, ephimerides of weather satellites, satellite decay predictions and other studies. Since their mission is operational, they do not store the data from their analyses. The ballistic coefficient is not known for most of the orbiting objects. If a ballistic coefficient were derived that was consistent with one density model, it might give erroneous results if used with a different density model. Given the ballistic coefficient, density values could, in principle, be obtained from their tracking data. The densities would represent an integrated mean over the orbital path near perigee. They would be model dependent and would not necessarily represent the real density. In summary, the primary need is for reliable forecasts of solar flux (F10.7) and geomagnetic activity (Ap) in the 1 to 4 week time scale. Forecasts over longer time spans would also be useful for special projects.

  6. Laser satellite power systems

    SciTech Connect

    Walbridge, E.W.

    1980-01-01

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  7. Larger Icy Satellites

    NASA Astrophysics Data System (ADS)

    Vance, Steven; Buratti, B. J.; Hansen, C.; Hurford, T.; McKinnon, W. B.; Pappalardo, R. T.; Turtle, E. P.

    2009-09-01

    Outer planets exploration in the past three decades has revealed a diverse host of large icy bodies undergoing a myriad of geological and chemical processes remarkably similar yet alien to those occurring on Earth. The most active of these, including the Galilean satellites and Saturn's moons Enceladus and Titan, are obvious targets for future robotic exploration. The broader host of satellites larger than 100 km should also figure into NASA's goals, owing to their abundance and insights they offer into past and present geological processes, Solar System formation and planetary evolution. Included in this class are the enigmatic objects Dione, with its smooth planes and fractured regions; Mimas with its giant crater Herschel; Iapetus, which has an odd shape and a mysterious equatorial ridge; Miranda, which has been subjected to drastic geologic reconfiguration; and Triton, with its geyser-like plumes. Many bodies in this class are of sufficient size and density to have hosted internal liquid water oceans in their early history, or even in the present epoch, making them targets of astrobiological interest. We discuss the importance of larger icy satellites to NASA's objectives, their importance for understanding, geology, chemistry and dynamics in the Solar System, and observational and experimental challenges that need to be addressed in the next decade.

  8. Communications satellites - The experimental years

    NASA Astrophysics Data System (ADS)

    Edelson, B. I.

    1983-10-01

    Only eight years after the launc of Sputnik-1 by the Soviet Union, the first commercial satellite, 'Early Bird', entered service. In just twelve years commercial satellite service extended around the earth and became profitable. The reasons for the successful development of the communications satellite services in a comparatively short time are considered. These reasons are related to the presence of three ingredients, taking into account technology to create the system, communications requirements to form a market, and a management structure to implement the system. The formation of the concept of using earth orbiting satellites for telecommunications is discussed. It is pointed out that the years from 1958 to 1964 were the true 'experimental years' for satellite communications. The rapid development of technology during this crucial period is described, giving attention to passive satellites, active systems, and development satellites.

  9. Communications satellites - The experimental years

    NASA Technical Reports Server (NTRS)

    Edelson, B. I.

    1983-01-01

    Only eight years after the launc of Sputnik-1 by the Soviet Union, the first commercial satellite, 'Early Bird', entered service. In just twelve years commercial satellite service extended around the earth and became profitable. The reasons for the successful development of the communications satellite services in a comparatively short time are considered. These reasons are related to the presence of three ingredients, taking into account technology to create the system, communications requirements to form a market, and a management structure to implement the system. The formation of the concept of using earth orbiting satellites for telecommunications is discussed. It is pointed out that the years from 1958 to 1964 were the true 'experimental years' for satellite communications. The rapid development of technology during this crucial period is described, giving attention to passive satellites, active systems, and development satellites.

  10. Optical satellite communications in Europe

    NASA Astrophysics Data System (ADS)

    Sodnik, Zoran; Lutz, Hanspeter; Furch, Bernhard; Meyer, Rolf

    2010-02-01

    This paper describes optical satellite communication activities based on technology developments, which started in Europe more than 30 years ago and led in 2001 to the world-first optical inter-satellite communication link experiment (SILEX). SILEX proved that optical communication technologies can be reliably mastered in space and in 2006 the Japanese Space Agency (JAXA) joined the optical inter-satellite experiment from their own satellite. Since 2008 the German Space Agency (DLR) is operating an inter-satellite link between the NFIRE and TerraSAR-X satellites based on a second generation of laser communication technology, which will be used for the new European Data Relay Satellite (EDRS) system to be deployed in 2013.

  11. New dimensions in satellite hydrology

    NASA Technical Reports Server (NTRS)

    Rango, A.; Salomonson, V. V.; Mcginnis, D. F.; Wiesnet, D. R.

    1974-01-01

    Consideration of the use of remote sensing technology applied from satellites to obtain information for the rapid and continuing assessment of the hydrologic cycle. A detailed account is given of the hydrological information made available through the activities of the ERTS-1 satellite, an experimental satellite entirely devoted to earth resources observations, and the NOAA-2 satellite, a high-resolution operational environmental satellite. Following a description of the satellites and their payloads, it is shown how with their aid information can be obtained regarding atmospheric moisture, surface water and snow cover, glaciers, potential flood situations, and subsurface water fluctuations. In addition, the use of the ERTS-1 and NOAA-2 satellites in watershed characterization and modeling and in monitoring water quality is discussed.

  12. Satellite Survivability Module

    NASA Astrophysics Data System (ADS)

    Buehler, P.; Smith, J.

    The Satellite Survivability Module (SSM) is an end-to-end, physics-based, performance prediction model for directed energy engagement of orbiting spacecraft. SSM was created as an add-on module for the Satellite Tool Kit (STK). Two engagement types are currently supported: laser engagement of the focal plane array of an imaging spacecraft; and Radio Frequency (RF) engagement of spacecraft components. This paper will focus on the laser engagement scenario, the process by which it is defined, and how we use this tool to support a future laser threat detection system experiment. For a laser engagement, the user creates a spacecraft, defines its optical system, adds any protection techniques used by the optical system, introduces a laser threat, and then defines the atmosphere through which the laser will pass. SSM models the laser engagement and its impact on the spacecraft's optical system using four impact levels: degradation, saturation, damage, and destruction. Protection techniques, if employed, will mitigate engagement effects. SSM currently supports two laser protection techniques. SSM allows the user to create and implement a variety of "what if" scenarios. Satellites can be placed in a variety of orbits. Threats can be placed anywhere on the Earth or, for version 2.0, on other satellites. Satellites and threats can be mixed and matched to examine possibilities. Protection techniques for a particular spacecraft can be turned on or off individually; and can be arranged in any order to simulate more complicated protection schemes. Results can be displayed as 2-D or 3-D visualizations, or as textual reports. A new report feature available in version 2.0 will allow laser effects data to be displayed dynamically during scenario execution. In order to test SSM capabilities, the Ball team used SSM to model several engagement scenarios for our future laser threat detection system experiment. Actual test sites, along with actual laser, optics, and detector

  13. ACTS Satellite Telemammography Network Experiments

    NASA Technical Reports Server (NTRS)

    Kachmar, Brian A.; Kerczewski, Robert J.

    2000-01-01

    The Satellite Networks and Architectures Branch of NASA's Glenn Research Center has developed and demonstrated several advanced satellite communications technologies through the Advanced Communications Technology Satellite (ACTS) program. One of these technologies is the implementation of a Satellite Telemammography Network (STN) encompassing NASA Glenn, the Cleveland Clinic Foundation. the University of Virginia, and the Ashtabula County Medical Center. This paper will present a look at the STN from its beginnings to the impact it may have on future telemedicine applications. Results obtained using the experimental ACTS satellite demonstrate the feasibility of Satellite Telemammography. These results have improved teleradiology processes and mammography image manipulation, and enabled advances in remote screening methodologies. Future implementation of satellite telemammography using next generation commercial satellite networks will be explored. In addition, the technical aspects of the project will be discussed, in particular how the project has evolved from using NASA developed hardware and software to commercial off the shelf (COTS) products. Development of asymmetrical link technologies was an outcome of this work. Improvements in the display of digital mammographic images, better understanding of end-to-end system requirements, and advances in radiological image compression were achieved as a result of the research. Finally, rigorous clinical medical studies are required for new technologies such as digital satellite telemammography to gain acceptance in the medical establishment. These experiments produced data that were useful in two key medical studies that addressed the diagnostic accuracy of compressed satellite transmitted digital mammography images. The results of these studies will also be discussed.

  14. Improved accuracies for satellite tracking

    NASA Technical Reports Server (NTRS)

    Kammeyer, P. C.; Fiala, A. D.; Seidelmann, P. K.

    1991-01-01

    A charge coupled device (CCD) camera on an optical telescope which follows the stars can be used to provide high accuracy comparisons between the line of sight to a satellite, over a large range of satellite altitudes, and lines of sight to nearby stars. The CCD camera can be rotated so the motion of the satellite is down columns of the CCD chip, and charge can be moved from row to row of the chip at a rate which matches the motion of the optical image of the satellite across the chip. Measurement of satellite and star images, together with accurate timing of charge motion, provides accurate comparisons of lines of sight. Given lines of sight to stars near the satellite, the satellite line of sight may be determined. Initial experiments with this technique, using an 18 cm telescope, have produced TDRS-4 observations which have an rms error of 0.5 arc second, 100 m at synchronous altitude. Use of a mosaic of CCD chips, each having its own rate of charge motion, in the focal place of a telescope would allow point images of a geosynchronous satellite and of stars to be formed simultaneously in the same telescope. The line of sight of such a satellite could be measured relative to nearby star lines of sight with an accuracy of approximately 0.03 arc second. Development of a star catalog with 0.04 arc second rms accuracy and perhaps ten stars per square degree would allow determination of satellite lines of sight with 0.05 arc second rms absolute accuracy, corresponding to 10 m at synchronous altitude. Multiple station time transfers through a communications satellite can provide accurate distances from the satellite to the ground stations. Such observations can, if calibrated for delays, determine satellite orbits to an accuracy approaching 10 m rms.

  15. Mobile satellite service communications tests using a NASA satellite

    NASA Technical Reports Server (NTRS)

    Chambers, Katherine H.; Koschmeder, Louis A.; Hollansworth, James E.; ONeill, Jack; Jones, Robert E.; Gibbons, Richard C.

    1995-01-01

    Emerging applications of commercial mobile satellite communications include satellite delivery of compact disc (CD) quality radio to car drivers who can select their favorite programming as they drive any distance; transmission of current air traffic data to aircraft; and handheld communication of data and images from any remote corner of the world. Experiments with the enabling technologies and tests and demonstrations of these concepts are being conducted before the first satellite is launched by utilizing an existing NASA spacecraft.

  16. Nano-Satellite Avionics

    NASA Technical Reports Server (NTRS)

    Culver, Harry

    1999-01-01

    Abstract NASA's Goddard Space Flight Center (GSFC) is currently developing a new class of satellites called the nano-satellite (nano-sat). A major objective of this development effort is to provide the technology required to enable a constellation of tens to hundreds of nano-satellites to make both remote and in-situ measurements from space. The Nano-sat will be a spacecraft weighing a maximum of 10 kg, including the propellant mass, and producing at least 5 Watts of power to operate the spacecraft. The electronics are required to survive a total radiation dose rate of 100 krads for a mission lifetime of two years. There are many unique challenges that must be met in order to develop the avionics for such a spacecraft. The first challenge is to develop an architecture that will operate on the allotted 5 Watts and meet the diverging requirements of multiple missions. This architecture will need to incorporate a multitude of new advanced microelectronic technologies. The microelectronics developed must be a modular and scalable packaging of technology to solve the problem of developing a solution to both reduce cost and meet the requirements of various missions. This development will utilize the most cost effective approach, whether infusing commercially driven semiconductor devices into spacecraft applications or partnering with industry to design and develop low cost, low power, low mass, and high capacity data processing devices. This paper will discuss the nano-sat architecture and the major technologies that will be developed. The major technologies that will be covered include: (1) Light weight Low Power Electronics Packaging, (2) Radiation Hard/Tolerant, Low Power Processing Platforms, (3) High capacity Low Power Memory Systems (4) Radiation Hard reconfiguragble field programmable gate array (rFPGA)

  17. The Galilean Satellites

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. From left to right, the moons shown are Ganymede, Callisto, Io, and Europa. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. In order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.

    The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity.

    North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element.

    The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft obtained the Io and Ganymede images in June 1996, while the Europa images were obtained in September 1996. Because Galileo focuses on high resolution imaging of regional areas on Callisto rather than global coverage, the portrait of Callisto is from the 1979 flyby of NASA's Voyager spacecraft.

    Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.

    This image and other images and data received from Galileo are posted on the World

  18. The Galilean Satellites

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. Shown from left to right in order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.

    The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity.

    North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element.

    The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft acquired the Io and Ganymede images in June 1996, the Europa images in September 1996, and the Callisto images in November 1997.

    Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web

  19. Tethered satellite system

    NASA Technical Reports Server (NTRS)

    Sisson, J.

    1986-01-01

    A reusable system is to be developed to enable a variety of scientific investigations to be accomplished from the shuttle, considering the use of a tethered system with manual or automated control, deployment of a satellite toward or away from the Earth, up to 100 km, and conducting or nonconducting tether. Experiments and scientific investigations are to be performed using the tether system for applications such as magnetometry, electrodynamics, atmospheric science, and chemical release. A program is being implemented as a cooperative U.S./Italian activity. The proposed systems, investigations, and the program are charted and briefly discussed.

  20. X-ray satellite

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An overview of the second quarter 1985 development of the X-ray satellite project is presented. It is shown that the project is proceeding according to plan and that the projected launch date of September 9, 1987 is on schedule. An overview of the work completed and underway on the systems, subsystems, payload, assembly, ground equipment and interfaces is presented. Problem areas shown include cost increases in the area of focal instrumentation, the star sensor light scattering requirements, and postponements in the data transmission subsystems.

  1. LDEF satellite radiation study

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    1994-01-01

    Some early results are summarized from a program under way to utilize LDEF satellite data for evaluating and improving current models of the space radiation environment in low earth orbit. Reported here are predictions and comparisons with some of the LDEF dose and induced radioactivity data, which are used to check the accuracy of current models describing the magnitude and directionality of the trapped proton environment. Preliminary findings are that the environment models underestimate both dose and activation from trapped protons by a factor of about two, and the observed anisotropy is higher than predicted.

  2. Synergy in satellite communication

    NASA Astrophysics Data System (ADS)

    Sachdev, D. K.

    1989-10-01

    After presenting a development history for satellite communications systems demonstrating the extent to which synergistic, efficiency-enhancing interactions between emerging technologies form the basis for much of the economic feasibility of these efforts, an evaluation is made of prospective synergisms. Among those identified as uniquely promising are the interactions of electric propulsion and Ni-H batteries, and of onboard data processing/bulk demultiplexing. An attempt is made to furnish a stimulus for system designers to actively seek out synergies rather than wait passively until they emerge.

  3. LDEF Satellite Radiation Analyses

    NASA Technical Reports Server (NTRS)

    Armstrong, T. W.; Colborn, B. L.

    1996-01-01

    Model calculations and analyses have been carried out to compare with several sets of data (dose, induced radioactivity in various experiment samples and spacecraft components, fission foil measurements, and LET spectra) from passive radiation dosimetry on the Long Duration Exposure Facility (LDEF) satellite, which was recovered after almost six years in space. The calculations and data comparisons are used to estimate the accuracy of current models and methods for predicting the ionizing radiation environment in low earth orbit. The emphasis is on checking the accuracy of trapped proton flux and anisotropy models.

  4. Future communications satellite applications

    NASA Technical Reports Server (NTRS)

    Bagwell, James W.

    1992-01-01

    The point of view of the research is made through the use of viewgraphs. It is suggested that future communications satellite applications will be made through switched point to point narrowband communications. Some characteristics of which are as follows: small/low cost terminals; single hop communications; voice compatible; full mesh networking; ISDN compatible; and possible limited use of full motion video. Some target applications are as follows: voice/data networks between plants and offices in a corporation; data base networking for commercial and science users; and cellular radio internodal voice/data networking.

  5. Radio broadcasting via satellite

    NASA Astrophysics Data System (ADS)

    Helm, Neil R.; Pritchard, Wilbur L.

    1990-10-01

    Market areas offering potential for future narrowband broadcast satellites are examined, including international public diplomacy, government- and advertising-supported, and business-application usages. Technical issues such as frequency allocation, spacecraft types, transmission parameters, and radio receiver characteristics are outlined. Service and system requirements, advertising revenue, and business communications services are among the economic issues discussed. The institutional framework required to provide an operational radio broadcast service is studied, and new initiatives in direct broadcast audio radio systems, encompassing studies, tests, in-orbit demonstrations of, and proposals for national and international commercial broadcast services are considered.

  6. Satellite attitude control simulations

    NASA Technical Reports Server (NTRS)

    Debra, D. B.; Powell, J. D.

    1973-01-01

    Work was conducted to develop an extremely low drift rate gyroscope and a very precise star tracker. A proposed relativity satellite will measure very accurately the theoretically predicted 'relativistic' precession of the gyroscope relative to an inertial reference frame provided by the star tracker. Aspects of precision spinning attitude control are discussed together with questions of gyro operation, and the hopping mode for lunar transportation. For the attitude control system of the lunar hopper, a number of control laws were investigated. The studies indicated that some suboptimal controls should be adequate for the system.

  7. A geopause satellite system concept

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1971-01-01

    A typical Geopause satellite orbit has a 14 hour period, a mean height of about 4.6 earth radii, and is nearly circular, polar, and normal to the ecliptic. At this height only a relatively few gravity terms have uncertainties corresponding to orbital perturbations above the decimeter level. The orbit is at the geopotential boundary, the geopause. The few remaining environmental quantities which may be significant can be determined by means of orbit analysis and accelerometers. The Geopause satellite system also provides the tracking geometry and coverage needed for determining the orbit, the tracking system biases and the station locations. Five or more fundamental stations well distributed in longitude can view Geopause over the North Pole. Geopause also provides the basic capability for satellite-to-satellite tracking of drag-free satellites for mapping the gravity field and altimeter satellites for surveying the sea surface topography.

  8. Satellite Vulnerability To Geomagnetic Storms

    NASA Astrophysics Data System (ADS)

    Horne, R. B.; Freemen, M. P.; Riley, D.; Daws, M.; Rutten, K.

    There are several examples where satellites on orbit have failed or partially failed during geomagnetic storms resulting in large insurance claims. Whether the storm is directly responsible for the failures is very controversial, commercially sensitive, and difficult to prove conclusively since there are so few examples. However, there are many non-fatal errors, or anomalies, that occur during the lifetime of spacecraft that enable a statistical analysis. Here we present an analysis of over 5000 satellite anomalies that shows for the first time a statistically significant link between satellite anomalies and geomagnetic storms. We find that the period of highest risk lasts for six days after the start of a magnetic storm. Approximately 40% of anomalies could be due to a random occurrence, but in addition there are between 0 and 35% of satellite anomalies that we attribute as being directly related to geomagnetic storms. We show that the risk depends on satellite prime contractor, orbit type, and age of satellite.

  9. Satellite stabilization using space leeches

    NASA Technical Reports Server (NTRS)

    Walker, Michael W.; Kim, Dong-Min

    1990-01-01

    A control algorithm for satellite stabilization using a space leech is presented. The space leech is assumed to have n reaction wheels with known moments of inertia about their axis of rotation. All mass properties of the satellite are assumed to be unknown. The algorithm brings the satellite to a specified attitude trajectory. Simulations were performed to demonstrate the controller. The model parameters and specific algorithm used and the results obtained are presented.

  10. TDRSS Augmentation System for Satellites

    NASA Technical Reports Server (NTRS)

    Heckler, Gregory W.; Gramling, Cheryl; Valdez, Jennifer; Baldwin, Philip

    2016-01-01

    In 2015, NASA Goddard Space Flight Center (GSFC) reinvigorated the development of the TDRSS Augmentation Service for Satellites (TASS). TASS is a global, space-based, communications and navigation service for users of Global Navigation Satellite Systems(GNSS) and the Tracking and Data Relay Satellite System (TDRSS). TASS leverages the existing TDRSS to provide an S-band beacon radio navigation and messaging source to users at orbital altitudes 1400 km and below.

  11. Trends in mobile satellite communication

    NASA Technical Reports Server (NTRS)

    Johannsen, Klaus G.; Bowles, Mike W.; Milliken, Samuel; Cherrette, Alan R.; Busche, Gregory C.

    1993-01-01

    Ever since the U.S. Federal Communication Commission opened the discussion on spectrum usage for personal handheld communication, the community of satellite manufacturers has been searching for an economically viable and technically feasible satellite mobile communication system. Hughes Aircraft Company and others have joined in providing proposals for such systems, ranging from low to medium to geosynchronous orbits. These proposals make it clear that the trend in mobile satellite communication is toward more sophisticated satellites with a large number of spot beams and onboard processing, providing worldwide interconnectivity. Recent Hughes studies indicate that from a cost standpoint the geosynchronous satellite (GEOS) is most economical, followed by the medium earth orbit satellite (MEOS) and then by the low earth orbit satellite (LEOS). From a system performance standpoint, this evaluation may be in reverse order, depending on how the public will react to speech delay and collision. This paper discusses the trends and various mobile satellite constellations in satellite communication under investigation. It considers the effect of orbital altitude and modulation/multiple access on the link and spacecraft design.

  12. The inner satellites of Jupiter

    NASA Technical Reports Server (NTRS)

    Veverka, J.; Thomas, P.; Synott, S.

    1981-01-01

    The Jupiter moon Amalthea and the smaller satellites J1, J2, and J3, discovered by Voyagers 1 and 2, are discussed under the collective appellation of 'inner satellites', which distinguishes them from the Galilean satellites and the outer satellites, J6-J13. Amalthea is a dark, irregular body on which two large craters are visible, with an estimated surface gravity of 5-7 cm/sec-squared. It is speculated that Amalthea's unique color/reflectance characteristics are due to prolonged charged particle and high-velocity micrometeoroid exposure. Dimensional data are presented for J1-3.

  13. Communications satellite systems capacity analysis

    NASA Technical Reports Server (NTRS)

    Browne, L.; Hines, T.; Tunstall, B.

    1982-01-01

    Analog and digital modulation techniques are compared with regard to efficient use of the geostationary orbit by communications satellites. Included is the definition of the baseline systems (both space and ground segments), determination of interference susceptibility, calculation of orbit spacing, and evaluation of relative costs. It is assumed that voice or TV is communicated at 14/11 GHz using either FM or QPSK modulation. Both the Fixed-Satellite Service and the Broadcasting-Satellite Service are considered. For most of the cases examined the digital approach requires a satellite spacing less than or equal to that required by the analog approach.

  14. Satellite communication for public services

    NASA Technical Reports Server (NTRS)

    Cooper, R. S.; Redisch, W. N.

    1977-01-01

    Public service programs using NASA's ATS-6 and CTS satellites are discussed. Examples include the ATS-6 Health and Education Telecommunications experimental program and the use of CTS to enable students in one university to take courses presented at another distant university. Possible applications of satellite communication systems to several areas of public service are described, and economic and political obstacles hindering the implementation of these programs are considered. It is suggested that a federally sponsored program demonstrating the utility of satellites accomodating a large number of small terminals is needed to encourage commercial satellite operations.

  15. Business Use of Satellite Communications.

    ERIC Educational Resources Information Center

    Edelson, Burton I.; Cooper, Robert S.

    1982-01-01

    Reviews business communications development and discusses business applications of satellite communications, system technology, and prospects for future developments in digital transmission systems. (JN)

  16. Baseband Processor for Communication Satellites

    NASA Technical Reports Server (NTRS)

    Jirberg, Russell J.; Armstrong, Patrick C.

    1987-01-01

    Baseband processing (BBP) system for advanced satellite communications successfully demonstrated. Provides increased data capacity through frequency-reusing multibeam antenna systems, using time-division multiple access (TDMA) and onboard satellite switching. Large numbers of thin-route trunking stations and user-based Earth terminals handled efficiently by satellite baseband switching. With BBP system, satellite routes data messages individually among locations anywhere in continental United States. Processes, controls, and routes message traffic among users. Time-division multiple access and baseband switching used.

  17. Land mobile satellite demonstration system

    NASA Technical Reports Server (NTRS)

    Gooch, Guy M.; Nicholas, David C.

    1988-01-01

    A land mobile satellite demonstration system is described. It ulilizes the INMARSAT MARECS B2 satellite at 26 degrees W. The system provides data transmission using a poll-response protocol with error detection and retransmission at 200 b/s rate. For most tests a 1.8 inch monopole antenna was used, along with a satellite EIRP normally used for four voice channels. A brief summary of the results are given and the overall system consisting of three elements in addition to the satellite (the mobile unit, the base station, and the office terminal and map display) is described. Throughput statistics from one trip are summarized.

  18. GSICS Satellite Intercalibration Products

    NASA Astrophysics Data System (ADS)

    Bali, M.; Flynn, L. E.

    2015-12-01

    Monitoring satellite instrument measurements (Top of Atmosphere radiances) while they are orbiting by comparing them with in-orbit stable references has emerged as a key component of ensuring quality (the stability and accuracy) of their measurements and correcting any biases that emerge during the mission. In 2006 the World Meteorological Organization (WMO) and the CGMS together initiated the Gobal Space Based Inter-Calibration System (GSICS,gsics.wmo.int) with the aim of monitoring the quality of measurement from satellite instruments launched by member including NASA, NOAA, EUMETSAT, ISRO CMA KMA CNES. In recent years, GSICS, via collaboration among member agencies across nations has successfully monitored instrument records for both GEO (GOES, SEVIRI, MTSAT) and LEO (AVHRR) based instruments by comparing them to in-orbit references such as IASI, AIRS and MODIS. The cross comparison products undergo stringent quality checks and standarizations and a scientific review of the theoretical bases and are assigned a GSICS maturity level. The accepted products are distributed freely as GSICS correction products. These products have wide applications. The goal of the presentation is to introduce GSICS cross calibration products and demonstrate their applications in developing products such as Fundamental Climate Data Records (FCDRs), evaluating Spectral Response Function status, and providing bias corrections. The impact of the GSICS bias corrections on retrieval of downstream variables such as Cloud Height Sea Surface Temperature will be one component of the presentation.

  19. The power relay satellite

    NASA Astrophysics Data System (ADS)

    Glaser, Peter E.

    The availability and use of renewable energy sources compatible with reducing risks to the global environment are key to sustainable development. Large-scale, renewable energy resources at undeveloped or underutilized sites are potentially available on several continents. The Power Relay Satellite (PRS) concept has the potential to access these remote energy resources by coupling primary electricity generation from terrestrial transmission lines. A global PRS network can be envisioned to provide a high degree of flexibility for supplying energy demands worldwide with wireless power transmitted from sites on Earth to geosynchronous orbit and then reflected to receivers interfacing with terrestrial power transmision networks. Past developments in wireless power transmission (WPT) are reviewed and recent successful results are noted. The origins of the PRS concept, and a possible configuration are discussed, principles of WPT at microwave frequencies, functional requirements, and system design contraints are outlined, and space transportation concepts presented. PRS assessments including applicable technologies, economic projections, and societal issues are highlighted. It is concluded that the PRS provides a promising option to access renewable resources at great distances from major markets, and represents an important stage in the future development in the future of solar power satellites.

  20. Solar power satellite

    SciTech Connect

    Copeland, R.J.; Martin, J.D.

    1983-11-15

    A solar power satellite includes a truss structure having a plurality of independently controlled solar power modules mounted to one face of the truss structure. The solar power satellite is constructed in orbit by first forming and then assemblying component beam members to the truss structure. The solar power modules are constructed on a fabrication and assembly station movably attached to the truss structure and are then attached to the truss structure. The solar power modules include a primary reflector having a substantially parabolic curvature in cross section. A collector-radiator is mounted on the primary axis of the primary reflector. The cross-sectional configuration of the collector-radiator approximates a flattened inverted S-shape whereon the radius of curvature decreases as the curve approaches both its center and its end furthermost from the primary reflector. The primary reflector is contoured to reflect sun light onto the collector-radiator structure. The collector-radiator structure includes a plurality of spaced radiant energy converting cells. A plurality of light reflective fins are positioned between the converter cells. Each fin is thermally and electrically connected to converter cells on each side thereof. The fins provide radiant cooling of and series electrical connection between the converter cells. The fins also serve as a secondary reflector for concentrating sun light from the primary reflector onto the converter cells.

  1. Determining satellite close approaches

    NASA Astrophysics Data System (ADS)

    Alfano, Salvatore; Negron, David, Jr.

    1993-06-01

    This paper presents a numerical method to evaluate close approaches of two satellites. The algorithm is based on a space curve modeling technique originally developed by Overhauser, presented here as an independent derivation. The method to determine minimum spacing between two space objects is based on creating a relative distance waveform, delta(t), versus time. The waveform is produced from either uniform or arbitrarily spaced data points, from which intervals of close approach are obtained by extracting the real roots of a localized cubic polynomial. This method is free of both transcendental equations and the computation of acceleration terms of the two objects of interest. For this study, a close approach truth table is constructed using a 0.1 second sequential step along the orbits, then differencing the two position vectors. The close approach entrance and exit times for an ellipsoidal quadric surface are then located using a piecewise linear interpolator, and serve as a benchmark for comparison. The simulation results show this algorithm produces encounter times almost identical to those in the truth table, with a 99.84 percent reduction in computer runtime. The results, created from real orbital data, include solution sets for three operational uses of close-approach logic. For this study, satellite orbital motion is modeled using first-order secular perturbations caused by mass anomalies.

  2. Satellite personal communications system

    NASA Technical Reports Server (NTRS)

    Reilly, N. B.; Smith, J. G. (Inventor)

    1980-01-01

    Voice channel communication between low power mobile stations dispersed over a large area is provided by a system which includes a geostationary satellite utilizing a large UHF antenna that can receive a transmission from a caller and retransmit it over any one beam of a matrix of narrow beams, so the chosen beam covers an area in which a designated called party is located. A single up-link control channel occupying a narrow frequency band, can be utilized to receive dial up signals from a caller, and another single down link control channel can be utilized to ring up the called party located anywhere within the continental United States. The satellite antenna includes a matrix of feed horns that not only direct the beams in a controlled matrix onto the area of the continental United States, but also permit detection of the region from which the caller's signal is transmitted and the region from which the called party's answer is received, to enable the interconnection of signals received from these two regions. The system is particularly useful for rural areas.

  3. Enceladus: a vanishing satellite

    NASA Astrophysics Data System (ADS)

    Czechowski, Leszek

    2014-05-01

    Enceladus, a satellite of Saturn, is the smallest celestial body in the Solar System where volcanic activity is observed. Every second, the mass of ~200 kg is ejecting into space. The size of the satellite directly after accretion (this body is referred here as proto-Enceladus) is unknown. It can be estimated in two ways. First, if the average mass outflow is equal to the present rate then the satellite's original mass was ~30% bigger than today. Second, we assume here that density of proto-Enceladus was equal to the present density of Mimas because they were formed in the same part of the nebula. Mimas is dead, so it preserves original composition. Both approaches give similar initial Enceladus' radius (~296 km) and its surface area (~1.1×106 km2). The present values are: 252 km and 7.99×105 km2. The loss of matter should lead to global compression of the crust. Typical effects of compression are: thrust faults, folding, and subduction. However, such forms are not dominant on Enceladus. We propose here special tectonic model that could explain this paradox. The volatiles escape from the hot region through the fractures forming plumes in the space. The loss of the volatiles results in a void, an instability, and motion of solid matter into hot region to fill the void in statu nascendi. The motion includes: Subsidence of the lithosphere of SPT. Flow of matter in the mantle. Motion of lithospheric plates adjacent to SPT towards the active region. If emerging void is being filled by the subsidence of SPT only, then the velocity of subsidence is ~0.05 mm·yr-1. However, all three types of motion are probably important, so the subsidence is slower but mantle flow and plates' motion also play a role in filling the void. Note that in our model reduction of the crust area is not a result of compression but it is a result of the plate sinking. Therefore the compressional surface features do not have to be dominant. Note also that we do not know the present age of the

  4. Gigabit Satellite Network for NASA's Advanced Communication Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

    The advanced communication technology satellite (ACTS) gigabit satellite network provides long-haul point-to-point and point-to-multipoint full-duplex SONET services over NASA's ACTS. at rates up to 622 Mbit/s (SONET OC-12), with signal quality comparable to that obtained with terrestrial fiber networks. Data multiplexing over the satellite is accomplished using time-division multiple access (TDMA) techniques coordinated with the switching and beam hopping facilities provided by ACTS. Transmissions through the satellite are protected with Reed-Solomon encoding. providing virtually error-free transmission under most weather conditions. Unique to the system are a TDMA frame structure and satellite synchronization mechanism that allow: (a) very efficient utilization of the satellite capacity: (b) over-the-satellite dosed-loop synchronization of the network in configurations with up to 64 ground stations: and (c) ground station initial acquisition without collisions with existing signalling or data traffic. The user interfaces are compatible with SONET standards, performing the function of conventional SONET multiplexers and. as such. can be: readily integrated with standard SONET fiber-based terrestrial networks. Management of the network is based upon the simple network management protocol (SNMP). and includes an over-the-satellite signalling network and backup terrestrial internet (IP-based) connectivity. A description of the ground stations is also included.

  5. The Future of Satellite Communications Technology.

    ERIC Educational Resources Information Center

    Nowland, Wayne

    1985-01-01

    Discusses technical advances in satellite technology since the 1960s, and the International Telecommunications Satellite Organization's role in these developments; describes how AUSSAT, Australia's domestic satellite system, exemplifies the latest developments in satellite technology; and reviews satellite system features, possible future…

  6. Sentinels in the Sky: Weather Satellites.

    ERIC Educational Resources Information Center

    Haynes, Robert

    This publication describes forecasting weather activity using satellites. Information is included on the development of weather satellites, the National Oceanic and Atmospheric Administration (NOAA) Satellite System (including the polar-orbiting satellites), and the Geostationary Operational Environmental Satellite (GOES). The publication…

  7. Satellite-Based Educational Services. Technical Memorandum.

    ERIC Educational Resources Information Center

    Operations Research, Inc., Silver Spring, MD.

    This memorandum contains engineering information relevant to the use of communication satellites for educational purposes. Information is provided for ground terminals as well as satellites. Satellite related issues addressed include: (1) expected life of service of various satellites, (2) constraints on the availability of the satellites, (3)…

  8. Multipurpose satellite bus (MPS)

    NASA Astrophysics Data System (ADS)

    The Naval Postgraduate School Advanced Design Project sponsored by the Universities Space Research Association Advanced Design Program is a multipurpose satellite bus (MPS). The design was initiated from a Statement of Work (SOW) developed by the Defense Advanced Research Projects Agency (DARPA). The SOW called for a 'proposal to design a small, low-cost, lightweight, general purpose spacecraft bus capable of accommodating any of a variety of mission payloads. Typical payloads envisioned include those associated with meteorological, communication, surveillance and tracking, target location, and navigation mission areas.' The design project investigates two dissimilar missions, a meteorological payload and a communications payload, mated with a single spacecraft bus with minimal modifications. The MPS is designed for launch aboard the Pegasus Air Launched Vehicle (ALV) or the Taurus Standard Small Launch Vehicle (SSLV).

  9. Polar research from satellites

    NASA Technical Reports Server (NTRS)

    Thomas, Robert H.

    1991-01-01

    In the polar regions and climate change section, the topics of ocean/atmosphere heat transfer, trace gases, surface albedo, and response to climate warming are discussed. The satellite instruments section is divided into three parts. Part one is about basic principles and covers, choice of frequencies, algorithms, orbits, and remote sensing techniques. Part two is about passive sensors and covers microwave radiometers, medium-resolution visible and infrared sensors, advanced very high resolution radiometers, optical line scanners, earth radiation budget experiment, coastal zone color scanner, high-resolution imagers, and atmospheric sounding. Part three is about active sensors and covers synthetic aperture radar, radar altimeters, scatterometers, and lidar. There is also a next decade section that is followed by a summary and recommendations section.

  10. Capture-ejector satellites

    NASA Technical Reports Server (NTRS)

    Macconochie, I. O.; Eldred, C. H.; Martin, J. A.

    1983-01-01

    A satellite in the form of a large rotating rim which can be used to boost spacecraft from low-Earth orbit to higher orbits is described. The rim rotates in the plane of its orbit such that the lower portion of the rim is traveling at suborbital velocity, while the upper portion is travelling at greater than orbital velocity. Ascending spacecraft or payloads arrive at the lowest portion of the rim at suborbital velocities, where the payloads are released on a trajectory for higher orbits; descending payloads employ the reverse procedure. Electric thrusters placed on the rim maintain rim rotational speed and altitude. From the standpoint of currently known materials, the capture-ejector concept may be useful for relatively small velocity increments.

  11. Multipurpose satellite bus (MPS)

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Naval Postgraduate School Advanced Design Project sponsored by the Universities Space Research Association Advanced Design Program is a multipurpose satellite bus (MPS). The design was initiated from a Statement of Work (SOW) developed by the Defense Advanced Research Projects Agency (DARPA). The SOW called for a 'proposal to design a small, low-cost, lightweight, general purpose spacecraft bus capable of accommodating any of a variety of mission payloads. Typical payloads envisioned include those associated with meteorological, communication, surveillance and tracking, target location, and navigation mission areas.' The design project investigates two dissimilar missions, a meteorological payload and a communications payload, mated with a single spacecraft bus with minimal modifications. The MPS is designed for launch aboard the Pegasus Air Launched Vehicle (ALV) or the Taurus Standard Small Launch Vehicle (SSLV).

  12. Satellite Rings Movie

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This brief movie clip (of which the release image is a still frame), taken by NASA's Cassini spacecraft as it approached Jupiter, shows the motions, over a 16 hour-period, of two satellites embedded in Jupiter's ring. The moon Adrastea is the fainter of the two, and Metis the brighter. Images such as these will be used to refine the orbits of the two bodies.

    The movie was made from images taken during a 40-hour sequence of the Jovian ring on December 11, 2000.

    Cassini is a cooperative mission of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages Cassini for NASA's Office of Space Science, Washington, D.C.

  13. Alaska's giant satellite network

    NASA Astrophysics Data System (ADS)

    Hills, A.

    1983-07-01

    The evolution and features of the Alaskan telecommunications network are described, with emphasis on the satellite links. The Alaskan terrain is rugged and largely unpopulated. Satcom V provides C-band (6/4 GHz) transmission with 24 transponders, each having a 40 MHz bandwidth. The Alascom company operated 105 4.5 m earth-based antennas for remote villages, which receive both telephone and television services. There are also 27 10-m dishes for regional and military applications and a 30 m dish, one of three dishes for links to the centerminous U.S. Currently, half the villages have private and business telephone communications facilities and 200 villages have access to two television stations, one educational, one entertainment. Teleconferencing is possible for government and educational purposes, and discussions are underway with NASA to establish a mobile radio communications capacity.

  14. Enceladus: a vanishing satellite

    NASA Astrophysics Data System (ADS)

    Czechowski, Leszek

    Enceladus, a satellite of Saturn, is the smallest celestial body in the Solar System where volcanic activity is observed. Every second, the mass of 200 kg is ejecting into space. The size of the satellite directly after accretion (this body is referred here as proto-Enceladus) is unknown. It can be estimated in two ways. First, if the average mass outflow is equal to the present rate then the satellite’s original mass was 30% bigger than today. Second, we assume here that density of proto-Enceladus was equal to the present density of Mimas because they were formed in the same part of the nebula. Mimas is dead, so it preserves original composition. Both approaches give similar initial Enceladus’ radius ( 296 km) and its surface area ( 1.1×106 km2). The present values are: 252 km and 7.99×105 km2. The loss of matter should lead to global compression of the crust. Typical effects of compression are: thrust faults, folding, and subduction. However, such forms are not dominant on Enceladus. We propose here special tectonic model that could explain this paradox. The volatiles escape from the hot region through the fractures forming plumes in the space. The loss of the volatiles results in a void, an instability, and motion of solid matter into hot region to fill the void in statu nascendi. The motion includes: (i) Subsidence of the lithosphere of SPT. (ii) Flow of matter in the mantle. (iii) Motion of lithospheric plates adjacent to SPT towards the active region. If emerging void is being filled by the subsidence of SPT only, then the velocity of subsidence is 0.05 mm·yr-1. However, all three types of motion are probably important, so the subsidence is slower but mantle flow and plates’ motion also play a role in filling the void. Note that in our model reduction of the crust area is not a result of compression but it is a result of the plate sinking. Therefore the compressional surface features do not have to be dominant. Note also that we do not know the

  15. Satellite Power System (SPS)

    NASA Technical Reports Server (NTRS)

    Edler, H. G.

    1978-01-01

    Potential organizational options for a solar power satellite system (SPS) were investigated. Selection and evaluation criteria were determined to include timeliness, reliability, and adequacy to contribute meaningfully to the U.S. supply; political feasibility (both national and international); and cost effectiveness (including environmental and other external costs). Based on these criteria, four organizational alternatives appeared to offer reasonable promise as potential options for SPS. A large number of key issues emerged as being factors which would influence the final selection process. Among these issues were a variety having to do with international law, international institutions, environmental controls, economics, operational flexibility, congressional policies, commercial-vs-governmental ownership, national dedication, and national and operational stategic issues.

  16. Accessing the Internet Via Satellite.

    ERIC Educational Resources Information Center

    Jackson, Lisa M.

    1998-01-01

    Discusses the use of satellite technology as an option for public schools to access the Internet. Examines costs and available technology. Presents two examples of school-satellite usage, including its use by the Navajo Nation to provide Internet access for its students who are spread out across 26,000 square miles. (GR)

  17. Satellite Technology Demonstration; Final Report.

    ERIC Educational Resources Information Center

    Federation of Rocky Mountain States, Inc., Denver, CO.

    The goal of the Satellite Technology Demonstration project (STD) was to show the feasibility of a satellite-based media system for isolated, rural populations and to test and evaluate user acceptance and the cost of various delivery modes using a variety of materials. The STD amalgamated the resources of government, health, education, and…

  18. Newspaper Uses of Satellite Technology.

    ERIC Educational Resources Information Center

    Johns, David

    Replacing slower mail service, satellite transmission now gives the newspaper industry a practical and almost spontaneous method for sending all kinds of information to any newspaper across the country. Unlike other communication industries, newspapers did not begin to make widespread use of satellite technology until 1979, when government…

  19. Drag-free satellite control

    NASA Technical Reports Server (NTRS)

    Debra, Daniel B.

    1989-01-01

    A drag-free satellite cancels the effect of external disturbances. Although the forces may be small, a satellite is disturbed by residual air drag, radiation pressure, micrometeorite impact, and other small forces that act on its surface disturbing its orbit, which is principally determined by the gravity field. In some missions, these small perturbations that make the satellite deviate from its purely gravitational orbit are limiting. An internal unsupported proof mass is shielded by the satellite from the external disturbances. The position of the shield (or the main part of the satellite) is measured with respect to the internal proof mass, and this information is used to actuate a propulsion system which moves the satellite to follow the proof mass. A drag-free control system is illustrated. Since the proof mass is shielded it follows a purely gravitational orbit - as does the satellite following it - hence the name drag-free satellite. The idea was conceived by Lange (1964) and has been applied to many mission studies since. In some cases, it is not necessary to cancel the disturbances, only to measure them so they may be taken into account. In such cases, an accelerometer may be a more suitable solution (for example, using the ONERA Cactus or the Bell Aerosystems MESA).

  20. A new satellite of saturn?

    PubMed

    Fountain, J W; Larson, S M

    1977-08-26

    Analysis of all available observations of faint objects near Saturn during the 1966 passage of the earth through the plane of Saturn's rings suggests the existence of at least one previously undiscovered satellite of Saturn. The data support the previously published orbit for Janus. These satellites may be major members of an extended ring. PMID:17730174

  1. Satellites: Teaching Technology Looks Up

    ERIC Educational Resources Information Center

    Lewis, Philip

    1973-01-01

    A Satellite will beam career education programs to 56 rural junior high schools and 12 public broadcasting stations in eight Rocky Mountain States. Programing on health, drug education, and English as a second language will be beamed to Alaskan elementary schools. Satellite beamed programs to India are planned on improving occupations skills, food…

  2. Satellite Demonstration: The Videodisc Technology.

    ERIC Educational Resources Information Center

    Propp, George; And Others

    1979-01-01

    Originally part of a symposium on educational media for the deaf, the paper describes a satellite demonstration of video disc materials. It is explained that a panel of deaf individuals in Washington, D.C. and another in Nebraska came into direct two-way communication for the first time, and video disc materials were broadcast via the satellite.…

  3. Radiocommunications for meteorological satellite systems

    NASA Technical Reports Server (NTRS)

    Walton, B. A.

    1975-01-01

    A general overview is presented of the spectrum utilization and frequency requirements of present and planned meteorological satellite programs. The sensors, and TIROS operational systems are discussed along with the Nimbus and Synchronous Meteorological Satellites. STORMSAT, SEASAT, and the Spacelab are briefly described.

  4. Satellite (IRLS) tracking of elk

    NASA Technical Reports Server (NTRS)

    Buechner, H. K.

    1972-01-01

    The practicability of tracking free roaming animals in natural environments by satellite systems is reported. Satellite systems combine continuous tracking with simultaneous monitoring of physiological and environmental parameters through a combination of radio tracking and biotelemetric ground systems that lead to a better understanding of animal behavior and migration patterns.

  5. Turnkey solutions for satellite operations

    NASA Astrophysics Data System (ADS)

    Greemillon, Philippe; Gaullier, Francois

    A unique expertise has been developed by Matra Marconi Space (MMS) in satellite operations covering all aspects of operations activities from mission design up to routine on-station operations. This paper describes the various aspects of MMS involvement in satellites operations with emphasis on satellite operations services which can be tailored to customer requirements in order to provide safe operations at low cost. For mission design and operations engineering specific tools and methods have been developed in order to reduce operation costs, perform early validation of satellite procedures, and ensure that return from in orbit experience is used as input for the design of the next programs. MMS has developed an enhanced ground control system based on modern architecture and using multifunction satellite operator workstations as well as orbit functions for colocated satellites and now in use for Hispasat and Telecom 2 at MMS Customer Support Center. Within MMS a Customer Support Center (CSC) has been set up based on this modern Satellite Control Center and connected to advanced AI tools. From the CSC, MMS is able to the propose a full range of operation services to the EUROSTAR customer from early satellite operations training up to Launch and Early Orbit Phase (LEOP) support and back up control center capability.

  6. Data distribution satellite

    NASA Technical Reports Server (NTRS)

    Stevens, Grady H.

    1992-01-01

    The Data Distribution Satellite (DDS), operating in conjunction with the planned space network, the National Research and Education Network and its commercial derivatives, would play a key role in networking the emerging supercomputing facilities, national archives, academic, industrial, and government institutions. Centrally located over the United States in geostationary orbit, DDS would carry sophisticated on-board switching and make use of advanced antennas to provide an array of special services. Institutions needing continuous high data rate service would be networked together by use of a microwave switching matrix and electronically steered hopping beams. Simultaneously, DDS would use other beams and on board processing to interconnect other institutions with lesser, low rate, intermittent needs. Dedicated links to White Sands and other facilities would enable direct access to space payloads and sensor data. Intersatellite links to a second generation ATDRS, called Advanced Space Data Acquisition and Communications System (ASDACS), would eliminate one satellite hop and enhance controllability of experimental payloads by reducing path delay. Similarly, direct access would be available to the supercomputing facilities and national data archives. Economies with DDS would be derived from its ability to switch high rate facilities amongst users needed. At the same time, having a CONUS view, DDS would interconnect with any institution regardless of how remote. Whether one needed high rate service or low rate service would be immaterial. With the capability to assign resources on demand, DDS will need only carry a portion of the resources needed if dedicated facilities were used. Efficiently switching resources to users as needed, DDS would become a very feasible spacecraft, even though it would tie together the space network, the terrestrial network, remote sites, 1000's of small users, and those few who need very large data links intermittently.

  7. Advanced satellite communication system

    NASA Technical Reports Server (NTRS)

    Staples, Edward J.; Lie, Sen

    1992-01-01

    The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

  8. 30 GHz Commercial Satellite Receivers

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Ponchak, George E.; Romanofsky, Robert R.

    1989-01-01

    NASA's research and development work in satellite communications for the past 10 years has included a major technology thrust aimed at opening the Ka frequency band to commercial exploitation. This has included the development and testing of advanced system network architectures, on-board switching and processing, multibeam and phased array antennas, and satellite and ground terminal RF and digital hardware. Development work in system hardware has focused on critical components including power amplifiers, satellite IF switch matrices, low noise receivers, baseband processors, and high data rate bandwidth efficient modems. This paper describes NASA's work in developing and testing 30 GHz low noise satellite receivers for commercial space communications uplink applications. Frequencies allotted for fixed service commercial satellite communications in the Ka band are 27.5 - 30.0 GHz for uplink transmission and 17.7 - 20.2 GHz for downlink transmission. The relatively large 2.5 GHz bandwidth lends itself to wideband, high data rate digital transmission applications.

  9. Meteorological Satellites and Their Data

    NASA Technical Reports Server (NTRS)

    Vaughn, W.

    1982-01-01

    This paper presents an overview of the meteorological satellite programs that have been evolving from 1958 to the present and reviews plans for the future meteorological and environmental satellite systems that are scheduled to be placed into service in the early 1980's. The development of the TIROS family of weather satellites, including TIROS, ESSA, ITOS/NOAA, and the present TIROS-N (the third-generation operational system) is summarized. The contribution of the Nimbus and ATS technology satellites to the development of the operational polar-orbiting and geostationary satellites is discussed. Included are descriptions of both the TIROS-N and the DMSP payloads currently under development to assure a continued and orderly growth of these systems into the 1980's.

  10. Land mobile satellite system requirements

    NASA Technical Reports Server (NTRS)

    Kiesling, J. D.

    1983-01-01

    A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

  11. Direct Broadcast Satellite: Radio Program

    NASA Technical Reports Server (NTRS)

    Hollansworth, James E.

    1992-01-01

    NASA is committed to providing technology development that leads to the introduction of new commercial applications for communications satellites. The Direct Broadcast Satellite-Radio (DBS-R) Program is a joint effort between The National Aeronautics and Space Administration (NASA) and The United States Information Agency/Voice of America (USIA/VOA) directed at this objective. The purpose of this program is to define the service and develop the technology for a direct-to-listener satellite sound broadcasting system. The DBS-R Program, as structured by NASA and VOA, is now a three-phase program designed to help the U.S. commercial communications satellite and receiver industry bring about this new communications service. Major efforts are being directed towards frequency planning hardware and service development, service demonstration, and experimentation with new satellite and receiver technology.

  12. Land mobile satellite system requirements

    NASA Astrophysics Data System (ADS)

    Kiesling, J. D.

    1983-05-01

    A Land Mobile Satellite System (LMSS) provides voice, data and related communications services to moving vehicles and persons. Communications between the mobiles and satellite are in the 806-890 MHz band. The satellite translates these signals to a ""fixed services band'' such as 14/12 GHz band (Ku-band), and communicates in this band with fixed terminals called gateways. The gateways are located at convenient places such as telephone switches (which provide entry into the national telephone system), dispatcher headquarters, computer centers, etc. Communications are therefore principally mobile to fixed. A third communications link, also at Ku-band, is needed between the satellite and a single fixed ground station. This link provides satellite command, telemetry and ranging and also provides a network control function. The latter, through a common signalling system, receives requests and assigns channel slots, and otherwise controls, monitors and polices the network and collects billing information.

  13. IP voice over ATM satellite: experimental results over satellite channels

    NASA Astrophysics Data System (ADS)

    Saraf, Koroush A.; Butts, Norman P.

    1999-01-01

    IP telephony, a new technology to provide voice communication over traditional data networks, has the potential to revolutionize telephone communication within the modern enterprise. This innovation uses packetization techniques to carry voice conversations over IP networks. This packet switched technology promises new integrated services, and lower cost long-distance communication compared to traditional circuit switched telephone networks. Future satellites will need to carry IP traffic efficiently in order to stay competitive in servicing the global data- networking and global telephony infrastructure. However, the effects of Voice over IP over switched satellite channels have not been investigated in detail. To fully understand the effects of satellite channels on Voice over IP quality; several experiments were conducted at Lockheed Martin Telecommunications' Satellite Integration Lab. The result of those experiments along with suggested improvements for voice communication over satellite are presented in this document. First, a detailed introduction of IP telephony as a suitable technology for voice communication over future satellites is presented. This is followed by procedures for the experiments, along with results and strategies. In conclusion we hope that these capability demonstrations will alleviate any uncertainty regarding the applicability of this technology to satellite networks.

  14. The Communications Satellite as Educational Tool.

    ERIC Educational Resources Information Center

    Long, Peter

    1982-01-01

    Drawing on the experiences of several countries, the author describes satellite technology, discusses the feasibility of satellite use in traditional educational institutions, and analyzes the role of satellites in social development. (SK)

  15. The exterior tidal potential acting on a satellite. [satellite orbits/satellite perturbation - gravitation effects

    NASA Technical Reports Server (NTRS)

    Musen, P.

    1975-01-01

    A theory is presented that points out the existence of several long period and 'cross effects' in the coefficients in the expansion of the geopotential and in the motion of satellites. The tidal potential, defined as small periodic variations in the geopotential, was calculated. The influence of these geopotential variations on satellite perturbation is examined. Spherical harmonics were employed.

  16. The Galilean Satellites

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this 'family portrait,' the four Galilean Satellites are shown to scale. These four largest moons of Jupiter shown in increasing distance from Jupiter are (left to right) Io, Europa, Ganymede, and Callisto.

    These global views show the side of volcanically active Io which always faces away from Jupiter, icy Europa, the Jupiter-facing side of Ganymede, and heavily cratered Callisto. The appearances of these neighboring satellites are amazingly different even though they are relatively close to Jupiter (350,000 kilometers for Io; 1, 800,000 kilometers for Callisto). These images were acquired on several orbits at very low 'phase' angles (the sun, spacecraft, moon angle) so that the sun is illuminating the Jovian moons from completely behind the spacecraft, in the same way a full moon is viewed from Earth. The colors have been enhanced to bring out subtle color variations of surface features. North is to the top of all the images which were taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

    Io, which is slightly larger than Earth's moon, is the most colorful of the Galilean satellites. Its surface is covered by deposits from actively erupting volcanoes, hundreds of lava flows, and volcanic vents which are visible as small dark spots. Several of these volcanoes are very hot; at least one reached a temperature of 2000 degrees Celsius (3600 degrees Fahrenheit) in the summer of 1997. Prometheus, a volcano located slightly right of center on Io's image, was active during the Voyager flybys in 1979 and is still active as Galileo images were obtained. This global view was obtained in September 1996 when Galileo was 485,000 kilometers from Io; the finest details that can be discerned are about 10 km across. The bright, yellowish and white materials located at equatorial latitudes are believed to be composed of sulfur and sulfur dioxide. The polar caps are darker and covered by a redder material.

    Europa has a very different surface from its

  17. The Galilean Satellites

    NASA Technical Reports Server (NTRS)

    1998-01-01

    In this 'family portrait,' the four Galilean Satellites are shown to scale. These four largest moons of Jupiter shown in increasing distance from Jupiter are (left to right) Io, Europa, Ganymede, and Callisto.

    These global views show the side of volcanically active Io which always faces away from Jupiter, icy Europa, the Jupiter-facing side of Ganymede, and heavily cratered Callisto. The appearances of these neighboring satellites are amazingly different even though they are relatively close to Jupiter (350,000 kilometers for Io; 1, 800,000 kilometers for Callisto). These images were acquired on several orbits at very low 'phase' angles (the sun, spacecraft, moon angle) so that the sun is illuminating the Jovian moons from completely behind the spacecraft, in the same way a full moon is viewed from Earth. The colors have been enhanced to bring out subtle color variations of surface features. North is to the top of all the images which were taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

    Io, which is slightly larger than Earth's moon, is the most colorful of the Galilean satellites. Its surface is covered by deposits from actively erupting volcanoes, hundreds of lava flows, and volcanic vents which are visible as small dark spots. Several of these volcanoes are very hot; at least one reached a temperature of 2000 degrees Celsius (3600 degrees Fahrenheit) in the summer of 1997. Prometheus, a volcano located slightly right of center on Io's image, was active during the Voyager flybys in 1979 and is still active as Galileo images were obtained. This global view was obtained in September 1996 when Galileo was 485,000 kilometers from Io; the finest details that can be discerned are about 10 km across. The bright, yellowish and white materials located at equatorial latitudes are believed to be composed of sulfur and sulfur dioxide. The polar caps are darker and covered by a redder material.

    Europa has a very different surface from its

  18. Military applications evolution and future. [meteorological satellites

    NASA Technical Reports Server (NTRS)

    Kaehn, A. J., Jr.

    1982-01-01

    The Defense Meteorological Satellite Program is described with particular emphasis on the military applications of METSAT data. Satellite operational support, data processing and image quality requirements are discussed.

  19. Multi-mission Satellite Management

    NASA Astrophysics Data System (ADS)

    Jamilkowski, M. L.; Teter, M. A.; Grant, K. D.; Dougherty, B.; Cochran, S.

    2015-12-01

    NOAA's next-generation environmental satellite, the Joint Polar Satellite System (JPSS) replaces the current Polar-orbiting Operational Environmental Satellites (POES). JPSS satellites carry sensors which collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The first JPSS satellite was launched in 2011 and is currently NOAA's primary operational polar satellite. The JPSS ground system is the Common Ground System (CGS), and provides command, control, and communications (C3) and data processing (DP). A multi-mission system, CGS provides combinations of C3/DP for numerous NASA, NOAA, DoD, and international missions. In preparation for the next JPSS satellite, CGS improved its multi-mission capabilities to enhance mission operations for larger constellations of earth observing satellites with the added benefit of streamlining mission operations for other NOAA missions. CGS's multi-mission capabilities allows management all of assets as a single enterprise, more efficiently using ground resources and personnel and consolidating multiple ground systems into one. Sophisticated scheduling algorithms compare mission priorities and constraints across all ground stations, creating an enterprise schedule optimized to mission needs, which CGS executes to acquire the satellite link, uplink commands, downlink and route data to the operations and data processing facilities, and generate the final products for delivery to downstream users. This paper will illustrate the CGS's ability to manage multiple, enterprise-wide polar orbiting missions by demonstrating resource modeling and tasking, production of enterprise contact schedules for NOAA's Fairbanks ground station (using both standing and ad hoc requests), deconflicting resources due to ground outages, and updating resource allocations through dynamic priority definitions.

  20. Security Concepts for Satellite Links

    NASA Astrophysics Data System (ADS)

    Tobehn, C.; Penné, B.; Rathje, R.; Weigl, A.; Gorecki, Ch.; Michalik, H.

    2008-08-01

    The high costs to develop, launch and maintain a satellite network makes protecting the assets imperative. Attacks may be passive such as eavesdropping on the payload data. More serious threat are active attacks that try to gain control of the satellite, which may lead to the total lost of the satellite asset. To counter these threats, new satellite and ground systems are using cryptographic technologies to provide a range of services: confidentiality, entity & message authentication, and data integrity. Additionally, key management cryptographic services are required to support these services. This paper describes the key points of current satellite control and operations, that are authentication of the access to the satellite TMTC link and encryption of security relevant TM/TC data. For payload data management the key points are multi-user ground station access and high data rates both requiring frequent updates and uploads of keys with the corresponding key management methods. For secure satellite management authentication & key negotiation algorithms as HMAC-RIPEMD160, EC- DSA and EC-DH are used. Encryption of data uses algorithms as IDEA, AES, Triple-DES, or other. A channel coding and encryption unit for payload data provides download data rates up to Nx250 Mbps. The presented concepts are based on our experience and heritage of the security systems for all German MOD satellite projects (SATCOMBw2, SAR-Lupe multi- satellite system and German-French SAR-Lupe-Helios- II systems inter-operability) as well as for further international (KOMPSAT-II Payload data link system) and ESA activities (TMTC security and GMES).

  1. Satellite Data Simulator Unit: A Multisensor, Multispectral Satellite Simulator Package

    NASA Technical Reports Server (NTRS)

    Masunaga, Hirohiko; Matsui, Toshihisa; Tao, Wei-Kuo; Hou, Arthur Y.; Kummerow, Christian D.; Nakajima, Teruyuki; Bauer, Peter; Olson, William S.; Sekiguchi, Miho; Nakajima, Teruyuki

    2010-01-01

    Several multisensor simulator packages are being developed by different research groups across the world. Such simulator packages [e.g., COSP , CRTM, ECSIM, RTTO, ISSARS (under development), and SDSU (this article), among others] share overall aims, although some are targeted more on particular satellite programs or specific applications (for research purposes or for operational use) than others. The SDSU or Satellite Data Simulator Unit is a general-purpose simulator composed of Fortran 90 codes and applicable to spaceborne microwave radiometer, radar, and visible/infrared imagers including, but not limited to, the sensors listed in a table. That shows satellite programs particularly suitable for multisensor data analysis: some are single satellite missions carrying two or more instruments, while others are constellations of satellites flying in formation. The TRMM and A-Train are ongoing satellite missions carrying diverse sensors that observe clouds and precipitation, and will be continued or augmented within the decade to come by future multisensor missions such as the GPM and Earth-CARE. The ultimate goals of these present and proposed satellite programs are not restricted to clouds and precipitation but are to better understand their interactions with atmospheric dynamics/chemistry and feedback to climate. The SDSU's applicability is not technically limited to hydrometeor measurements either, but may be extended to air temperature and humidity observations by tuning the SDSU to sounding channels. As such, the SDSU and other multisensor simulators would potentially contribute to a broad area of climate and atmospheric sciences. The SDSU is not optimized to any particular orbital geometry of satellites. The SDSU is applicable not only to low-Earth orbiting platforms as listed in Table 1, but also to geostationary meteorological satellites. Although no geosynchronous satellite carries microwave instruments at present or in the near future, the SDSU would be

  2. Laser geodynamic satellite (LAGEOS II)

    NASA Technical Reports Server (NTRS)

    Portelli, C.; Ousley, G. W., Sr.

    1991-01-01

    The Laser Geodynamic Satellite 2 (LAGEOS 2) is nearly identical to the LAGEOS 1 satellite, which was launched by NASA in 1976. However, LAGEOS 2 is completely passive, and is equipped with fused silian corner reflectors for ranging with ground-based lasers. The addition of LAGEOS 2 will provide the GSFC laser network with significantly increased satellite tracking opportunities, because LAGEOS 1 is at a 110-degree inclination and LAGEOS 2 will be at a 52-degree inclination. The flight profile is given, and information is presented in tabular form on the following topics: Deep Space Network support, frequency assignments, telemetry, tracking, and tracking support responsibility.

  3. Advanced Communications Technology Satellite (ACTS)

    NASA Astrophysics Data System (ADS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-06-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  4. The economics of satellite retrieval

    NASA Technical Reports Server (NTRS)

    Price, Kent M.; Greenberg, Joel S.

    1988-01-01

    The economics of space operations with and without the Space Station have been studied in terms of the financial performance of a typical communications-satellite business venture. A stochastic Monte-Carlo communications-satellite business model is employed which includes factors such as satellite configuration, random and wearout failures, reliability of launch and space operations, stand-down time resulting from failures, and insurance by operation. Financial performance impacts have been evaluated in terms of the magnitude of investment, net present value, and return on investment.

  5. Coding for reliable satellite communications

    NASA Technical Reports Server (NTRS)

    Gaarder, N. T.; Lin, S.

    1986-01-01

    This research project was set up to study various kinds of coding techniques for error control in satellite and space communications for NASA Goddard Space Flight Center. During the project period, researchers investigated the following areas: (1) decoding of Reed-Solomon codes in terms of dual basis; (2) concatenated and cascaded error control coding schemes for satellite and space communications; (3) use of hybrid coding schemes (error correction and detection incorporated with retransmission) to improve system reliability and throughput in satellite communications; (4) good codes for simultaneous error correction and error detection, and (5) error control techniques for ring and star networks.

  6. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) was conceived to help maintain U.S. leadership in the world's communications-satellite market. This experimental satellite is expected to be launched by NASA in 1992 and to furnish the technology necessary for establishing very small aperture terminal digital networks which provide on-demand full-mesh connectivity, and 1.544-MBPS services with only a single hop. Utilizing on-board switching and processing, each individual voice or data circuit can be separately routed to any location in the network. This paper provides an overview of the ACTS and discusses the value of the technology for future communications systems.

  7. Satellite TV in the UK

    NASA Astrophysics Data System (ADS)

    Stanyard, Roger

    1991-11-01

    The development of DBS TV is considered in terms of the type of supporting satellite to be selected with attention given to the medium-power concept FSS satellites. Predictions are made regarding the combination direct-to-home/DBS satellite-broadcasting industry emphasizing the use of DBS TV for program delivery and not as a substitute for cable and other distribution methods. DBS TV is an effective technology for reaching audience segments that cannot be included by conventional terrestrial and cable means.

  8. Use of communications. [satellite communication

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Progress in the field of satellite communications is reviewed, and useful services which may be provided by future satellite communications systems are considered. Recommendations are made with regard to mobile communications for use on land and at sea, position determination, mineral and energy exploration, the possibility of using electronic means to assist in main delivery, education and health-care experiments, and the use of satellite telecommunications to enhance the quality of life in rural areas by making available a full range of educational and entertainment programs. The needs of the amateur radio community are also considered.

  9. Hubble Space Telescope satellite

    NASA Technical Reports Server (NTRS)

    Mitchell, R. E.

    1985-01-01

    The Hubble Space Telescope, named for the American astronomer Edwin Powell Hubble, will be the largest and most powerful astronomical instrument ever orbited. Placed above the obscuring effects of the earth's atmosphere in a 600-km orbit, this remotely-controlled, free-flying satellite observatory will expand the terrestrial-equivalent resolution of the universe by a factor of seven, or a volumetric factor of 350. This telescope has a 2.4-m primary mirror and can accommodate five scientific instruments (cameras, spectrographs and photometers). The optics are suitable for a spectral range from 1100 angstrom to 1 mm wavelength. With a projected service life of fifteen years, the spacecraft can be serviced on-orbit for replacement of degraded systems, to insert advanced scientific instruments, and to reboost the telescope from decayed altitudes. The anticipated image quality will be a result of extremely precise lambda/20 optics, stringent cleanliness, and very stable pointing: jitter will be held to less than 0.01 arcsecond for indefinite observation periods, consistent with instrument apertures as small as 0.1 arcsecond.

  10. Satellite Propellant Pump Research

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Veres, Joseph P.; Hah, Chunill; Nerone, Anthony L.; Cunningham, Cameron C.; Kraft, Thomas G.; Tavernelli, Paul F.; Fraser, Bryan

    2005-01-01

    NASA Glenn initiated a satellite propellant pump technology demonstration program. The goal was to demonstrate the technologies for a 60 percent efficient pump at 1 gpm flow rate and 500 psia pressure rise. The pump design and analysis used the in-house developed computer codes named PUMPA and HPUMP3D. The requirements lead to a 4-stage impeller type pump design with a tip diameter of 0.54 inches and a rotational speed of 57,000 rpm. Analyses indicated that flow cavitation was not a problem in the design. Since the flow was incompressible, the stages were identical. Only the 2-stage pump was designed, fabricated, assembled, and tested for demonstration. Water was selected as the surrogate fluid for hydrazine in this program. Complete mechanical design including stress and dynamic analyses were conducted. The pump was driven by an electric motor directly coupled to the impellers. Runs up to 57,000 rpm were conducted, where a pressure rise of 200 psia at a flow rate of 0.8 gpm was measured to validate the design effort.

  11. Satellite Technology for Education Distribution

    ERIC Educational Resources Information Center

    Campbell, Jack M.

    1974-01-01

    The use of satellite technology to bring much needed information, such as career education messages to remote areas of Rocky Mountain States is the subject of this paper. Both software and hardware aspects of this demonstration project are discussed. (Author)

  12. Cloudsat Satellite Images of Amanda

    NASA Video Gallery

    NASA's CloudSat satellite flew over Hurricane Amanda on May 25, at 5 p.m. EDT and saw a deep area of moderate to heavy-moderate precipitation below the freezing level (where precipitation changes f...

  13. Visual Data Analysis for Satellites

    NASA Technical Reports Server (NTRS)

    Lau, Yee; Bhate, Sachin; Fitzpatrick, Patrick

    2008-01-01

    The Visual Data Analysis Package is a collection of programs and scripts that facilitate visual analysis of data available from NASA and NOAA satellites, as well as dropsonde, buoy, and conventional in-situ observations. The package features utilities for data extraction, data quality control, statistical analysis, and data visualization. The Hierarchical Data Format (HDF) satellite data extraction routines from NASA's Jet Propulsion Laboratory were customized for specific spatial coverage and file input/output. Statistical analysis includes the calculation of the relative error, the absolute error, and the root mean square error. Other capabilities include curve fitting through the data points to fill in missing data points between satellite passes or where clouds obscure satellite data. For data visualization, the software provides customizable Generic Mapping Tool (GMT) scripts to generate difference maps, scatter plots, line plots, vector plots, histograms, timeseries, and color fill images.

  14. Ephemeris representations for communications satellites

    NASA Astrophysics Data System (ADS)

    Proulx, R. J.; Cefola, P. J.; McClain, W. D.

    1984-08-01

    Large orbit determination (OD) centers are the primary source of artificial satellite ephemeris data. The ephemeris message of the OD facility contains implicitly the predicted satellite trajectory. The user can recover ephemeris data on the basis of two conceptual approaches. The current investigation is concerned with an alternative solution to the ephemeris representation problem. According to the procedure employed in this case, the mean equinoctial element time histories corresponding to the predicted satellite trajectory generated by the OD facility are approximated by low degree Legendre polynomials to represent their secular behavior and by trigonometric terms to represent their mean periodic behavior. This approach provides a simple, low cost, and accurate ephemeris representation, which satisfies the potential autonomy requirements for Military Satellite Communications.

  15. Synchronous Earth Observatory Satellite /SEOS/

    NASA Technical Reports Server (NTRS)

    Walter, L. S.

    1974-01-01

    NASA/GSFC is currently studying the applications and technical requirements for a Synchronous Earth Observations Satellite (SEOS). Such a satellite would combine the relatively high resolution and multi-spectral capability of the Earth Resources Technology Satellite (ERTS) with the on-station continuous monitoring of the Synchronous Meteorological Satellite (SMS). SEOS capability is geared to perform disaster warning of tornadoes and floods as well as to monitor transient phenomena affecting earth resources (e.g., green waves and algae blooms). The heart of the system is a Large Earth Survey Telescope (LEST) which has a designed 1.5 meter diameter. Spectral bands in the visible, near- and far-infrared have been selected to optimize SEOS utility. A microwave sounder will be used in conjunction with the LEST for meteorological applications.

  16. Commercial satellite broadcasting for Europe

    NASA Astrophysics Data System (ADS)

    Forrest, J. R.

    1988-12-01

    A review is presented of the current television broadcasting situation in European countries, which involves a varied mix of terrestrial VHF or UHF systems and cable networks. A small market has emerged in Europe for receivers using the low-power telecommunications satellite transmission between the program providers and cable network companies. This is expected to change with the launch of medium-power pan-European telecommunication satellites (e.g. ASTRA, EUTELSAT II), which are now directly addressing the market of home reception. DBS (direct broadcast satellite) in the UK, using the D-MAC transmission standard, will offer three additional television channels, data broadcasting services, and a planned evolution to compatible forms of wide-screen, high-definition television. Comments are given on receiver and conditional access system standardization. Some views are expressed on satellite broadcasting as part of an overall broadcasting framework for the future.

  17. Satellite Movie Shows Erika Dissipate

    NASA Video Gallery

    This animation of visible and infrared imagery from NOAA's GOES-West satellite from Aug. 27 to 29 shows Tropical Storm Erika move through the Eastern Caribbean Sea and dissipate near eastern Cuba. ...

  18. Satellite Imagery Via Personal Computer

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Automatic Picture Transmission (APT) was incorporated by NASA in the Tiros 8 weather satellite. APT included an advanced satellite camera that immediately transmitted a picture as well as low cost receiving equipment. When an advanced scanning radiometer was later introduced, ground station display equipment would not readily adjust to the new format until GSFC developed an APT Digital Scan Converter that made them compatible. A NASA Technical Note by Goddard's Vermillion and Kamoski described how to build a converter. In 1979, Electro-Services, using this technology, built the first microcomputer weather imaging system in the U.S. The company changed its name to Satellite Data Systems, Inc. and now manufactures the WeatherFax facsimile display graphics system which converts a personal computer into a weather satellite image acquisition and display workstation. Hardware, antennas, receivers, etc. are also offered. Customers include U.S. Weather Service, schools, military, etc.

  19. Small satellite radiometric measurement system

    SciTech Connect

    Weber, P.G.

    1992-01-01

    A critical need for the US Global Change Research Program is to provide continuous, well-calibrated radiometric data for the earth`s radiation budget. This paper describes a new, compact, relatively light-weight, adaptable radiometer which will provide both spectrally integrated measurements and data in selected spectral bands. The radiometer design is suitable for use on small satellites, aircraft, or remotely piloted aircraft (RPAs). An example of the implementation of this radiometer on a small satellite is given. Significant benefits derive from simultaneous measurements of specific narrow (in wavelength) spectral features; such data may be obtained by combining LARI with a compact spectrometer on the same platform. Well-chosen satellite orbits allow one to use data from other satellites (e.g. DMSP) to enhance the data product, or to provide superior coverage of specific locations. 23 refs.

  20. Telemetry systems of Interkosmos satellites

    NASA Astrophysics Data System (ADS)

    Hetenyi, T.

    1985-02-01

    The INTERKOZMOS space research organization of the socialist countries has been conducting regular scientific research of the region about the Earth since the middle 1960's. Efforts to standardize the telemetry of INTERKOSMOS satellites are reported.

  1. Satellite Teleconferencing in the Caribbean.

    ERIC Educational Resources Information Center

    Sankar, Hollis C.

    1985-01-01

    Discusses the need for, and the development, use, and future trends of, the University of the West Indies Distance Teaching Experiment, which utilizes telephone and communications satellite technology teleconferencing to extend educational opportunities to the peoples of the Caribbean. (MBR)

  2. Earth Resources Technology Satellite (ERTS)

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The Earth Resources Technology Satellite (ERTS) mock-up in a space chamber test at General Electric's Space Division. The ERTS program represented a concentrated effort to observe and monitor the limited resources of the Earth, in order to best conserve and utilize the resources in support of a burgeoning world population. The first ERTS was launched in 1972 and was later named Land Remote-Sensing Satellite (Landsat), to better represent the civil satellite program's prime emphasis on remote sensing of land resources. Multiple sensors survey and relay back masses of data in various ways from the Landsat. NASA has built 7 Land Remote Sensing Satellites, which have helped agricultural experts pick up underutilized land areas and new prospects for land use through irrigation. It has also assisted in pinpointing the spread of crop disease and in charting new uses of the sea for oceanographers.

  3. NASA's TRMM Satellite Captures Cosme

    NASA Video Gallery

    On Tuesday, June 25, Cosme became a hurricane. NASA's TRMM satellite flew over Cosme at 9:46 a.m. EDT shortly before it was upgraded to a hurricane. A rainfall analysis from TRMM's Microwave Imager...

  4. TRMM Satellite Video of Amara

    NASA Video Gallery

    TRMM satellite on Dec. 16, at 2043 UTC showed scattered bands of moderate to heavy rain falling at a rate of over 76.9 mm/3 inches per hour spiraling into Amara's center. Cloud tops reached 13km/~8...

  5. Existence of undiscovered Uranian satellites

    SciTech Connect

    Boice, D.C.

    1986-04-01

    Structure in the Uranian ring system as observed in recent occultations may contain indirect evidence for the existence of undiscovered satellites. Using the Alfven and Arrhenius (1975, 1976) scenario for the formation of planetary systems, the orbital radii of up to nine hypothetical satellites interior to Miranda are computed. These calculations should provide interesting comparisons when the results from the Voyager 2 encounter with Uranus are made public. 15 refs., 1 fig., 1 tab.

  6. Legal aspects of satellite teleconferencing

    NASA Technical Reports Server (NTRS)

    Smith, D. D.

    1971-01-01

    The application of satellite communications for teleconferencing purposes is discussed. The legal framework within which such a system or series of systems could be developed is considered. The analysis is based on: (1) satellite teleconferencing regulation, (2) the options available for such a system, (3) regulatory alternatives, and (4) ownership and management aspects. The system is designed to provide a capability for professional education, remote medical diagnosis, business conferences, and computer techniques.

  7. Satellite lifetime routine user's manual

    NASA Technical Reports Server (NTRS)

    Everett, H. U.; Myler, T. R.

    1975-01-01

    A FORTRAN coded computer program which determines secular variations in mean orbital elements of earth satellites and the lifetime of the orbit is described. The dynamical model treats a point mass satellite subject to solar and lunar disturbing gravitational fields, second, third and fourth harmonics of the earth's oblate potential, earth's atmospheric drag, and solar radiation pressure. Each of these disturbing functions may be selectively simulated. Data preparation instructions, a sample problem, and definitions of output quantities are included.

  8. The data distribution satellite system

    NASA Technical Reports Server (NTRS)

    Bruno, Ronald C.; Weinberg, Aaron

    1991-01-01

    The Data Distributed Satellite (DDS) will be capable of providing the space research community with inexpensive and easy access to space payloads and space data. Furthermore, the DDS is shown to be a natural outgrowth of advances and evolution in both NASA's Space Network and commercial satellite communications. The roadmap and timescale for this evolution is described along with key demonstrations, proof-of-concept models, and required technology development that will support the projected system evolution toward the DDS.

  9. Intelsat satellite scheduled for launch

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The launch schedule for Intelsat 5-B, the prime Intelsat satellite to provide communications services between the Americas, Europe, the Middle East, and Africa, is presented. The planned placement of the satellite into an elliptical transfer orbit, and circularization of the orbit at geosynchronous altitude over the equator are described. Characteristics of the Atlas Centaur launch vehicle, AC-56, are given. The launch operation is summarized and the launch sequence presented. The Intelsat team and contractors are listed.

  10. ARJIS satellite demonstration project

    NASA Astrophysics Data System (ADS)

    Severance, Steve; Williams, Carl

    2005-06-01

    In 2003, the California Space Authority (CSA) was provided funding by the U. S. Congress through the Defense Appropriations Act to develop a project that would demonstrate the U.S. space enterprise capability that would contribute to the effectiveness of those engaged in Homeland Security. The project was given broad latitude in selecting the area of Homeland Security to be addressed and the nature of the space technology to be applied. CSA became aware of a nascent law enforcement data-sharing project in the San Diego region known as the Automated Regional Justice Information System (ARJIS). First developed by the police departments in San Diego, ARJIS is an innovative system that shares criminal justice information among 50 federal, state, and local agencies. ARJIS was completing a pilot project that enabled officers to receive information on handheld computers, which was transmitted wirelessly through cellular networks. The accessed information came from several databases that collectively contained the entire region's crime and arrest reports, traffic citations, and incidents, as well as state and county wants and warrants. The fundamental limitations that plague all cellular-based devices caught CSA's attention and resulted in a cooperative effort to harden the communications link between the patrol officer and critical data. The principal goal of the SATCOM development task was to create a proof-of-concept application that would use SATCOM links to augment the current ARJIS handheld wireless (cellular) capability. The successful technical demonstration and the positive support for satellite communications from the law enforcement community showed that this project filled a need-both for improved information sharing and for highly reliable communications systems.

  11. Satellite medical centers project

    NASA Astrophysics Data System (ADS)

    Aggarwal, Arvind

    2002-08-01

    World class health care for common man at low affordable cost: anywhere, anytime The project envisages to set up a national network of satellite Medical centers. Each SMC would be manned by doctors, nurses and technicians, six doctors, six nurses, six technicians would be required to provide 24 hour cover, each SMC would operate 24 hours x 7 days. It would be equipped with the Digital telemedicine devices for capturing clinical patient information and investigations in the form of voice, images and data and create an audiovisual text file - a virtual Digital patient. Through the broad band connectivity the virtual patient can be sent to the central hub, manned by specialists, specialists from several specialists sitting together can view the virtual patient and provide a specialized opinion, they can see the virtual patient, see the examination on line through video conference or even PCs, talk to the patient and the doctor at the SMC and controlle capturing of information during examination and investigations of the patient at the SMC - thus creating a virtual Digital consultant at the SMC. Central hub shall be connected to the doctors and consultants in remote locations or tertiary care hospitals any where in the world, thus creating a virtual hub the hierarchical system shall provide upgradation of knowledge to thedoctors in central hub and smc and thus continued medical education and benefit the patient thru the world class treatment in the smc located at his door step. SMC shall be set up by franchisee who shall get safe business opportunity with high returns, patients shall get Low cost user friendly worldclass health care anywhere anytime, Doctors can get better meaningful selfemplyment with better earnings, flexibility of working time and place. SMC shall provide a wide variety of services from primary care to world class Global consultation for difficult patients.

  12. Assimilation of Satellite Ozone Observations

    NASA Technical Reports Server (NTRS)

    Stajner, I.; Winslow, N.; Wargan, K.; Hayashi, H.; Pawson, S.; Rood, R.

    2003-01-01

    This talk will discuss assimilation of ozone data from satellite-borne instruments. Satellite observations of ozone total columns and profiles have been measured by a series of Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet (SBUV) instruments, and more recently by the Global Ozone Monitoring Experiment. Additional profile data are provided by instruments on NASA's Upper Atmosphere Research Satellite and by occultation instruments on other platforms. Instruments on Envisat' and future EOS Aura satellite will supply even more comprehensive data about the ozone distribution. Satellite data contain a wealth of information, but they do not provide synoptic global maps of ozone fields. These maps can be obtained through assimilation of satellite data into global chemistry and transport models. In the ozone system at NASA's Data Assimilation Office (DAO) any combination of TOMS, SBUV, and Microwave Limb sounder (MLS) data can be assimilated. We found that the addition of MLS to SBUV and TOMS data in the system helps to constrain the ozone distribution, especially in the polar night region and in the tropics. The assimilated ozone distribution in the troposphere and lower stratosphere is sensitive also to finer changes in the SBUV and TOMS data selection and to changes in error covariance models. All results are established by comparisons of assimilated ozone with independent profiles from ozone sondes and occultation instruments.

  13. 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.

  14. The American mobile satellite system

    NASA Technical Reports Server (NTRS)

    Garner, William B.

    1990-01-01

    During 1989, the American Mobile Satellite Corporation (AMSC) was authorized to construct, launch, and operate satellites to provide mobile satellite services (MSS) to the U.S. and Puerto Rico. The AMSC has undertaken three major development programs to bring a full range of MSS services to the U.S. The first program is the space segment program that will result in the construction and launch of the satellites as well as the construction and installation of the supporting ground telemetry and command system. The second segment will result in the specification, design, development, construction, and installation of the Network Control System necessary for managing communications access to the satellites, and the specification and development of ground equipment for standard circuit switched and packet switched communications services. The third program is the Phase 1 program to provide low speed data services within the U.S. prior to availability of the AMSC satellites and ground segment. Described here are the present status and plans for these three programs as well as an update on related business arrangements and regulatory matters.

  15. Communications satellites versus fiber optics

    NASA Astrophysics Data System (ADS)

    Goldman, A. M., Jr.

    Examples of the interfaces encountered in the provision of intercity, long-distance service in the U.S. are examined, and a comparison is conducted of the costs of the Intercity, Long-Distance portion of a single voice circuit derived from either fixed satellite trunking service or fiber optic bulk capacity. It is estimated that by the end of 1988, fiber optic should span the nation connecting New York and Washington with Los Angeles and San Francisco. It is shown that once fiber connects a given pair of cities, it becomes the least costly transmission medium, especially compared to fixed satellite service. Attention is given to equivalent transmission capacities, six providers of fiber optic capacity, a total satellite capacity comparison, an economic lifetime comparison, satellite and fiber optic network maps, satellite city-pair distance and cost matrices, and fiber optic city-pair distance matrices. It is pointed out that certain future CONUS satellite service applications will be inherently invulnerable to terrestrial fiber optics serving fixed routes.

  16. Odyssey personal communications satellite system

    NASA Technical Reports Server (NTRS)

    Spitzer, Christopher J.

    1993-01-01

    The spectacular growth of cellular telephone networks has proved the demand for personal communications. Large regions of the world are too sparsely populated to be economically served by terrestrial cellular communications. Since satellites are well suited to this application, TRW filed with the FCC on May 31, 1993 for the Odyssey construction permit. Odyssey will provide high quality wireless communication services worldwide from satellites. These services will include: voice, data, paging, and messaging. Odyssey will be an economical approach to providing communications. A constellation of 12 satellites will be orbited in three, 55 deg. inclined planes at an altitude of 10,354 km to provide continuous coverage of designated regions. Two satellites will be visible anywhere in the world at all times. This dual visibility leads to high line-of-sight elevation angles, minimizing obstructions by terrain, trees and buildings. Each satellite generates a multibeam antenna pattern that divides its coverage area into a set of contiguous cells. The communications system employs spread spectrum CDMA on both the uplinks and downlinks. This signaling method permits band sharing with other systems and applications. Signal processing is accomplished on the ground at the satellite's 'Gateway' stations. The 'bent pipe' transponders accommodates different regional standards, as well as signaling changes over time. The low power Odyssey handset will be cellular compatible. Multipath fade protection is provided in the handset.

  17. A satellite for demonstration of Panel Extension Satellite (PETSAT)

    NASA Astrophysics Data System (ADS)

    Sugawara, Yoshiki; Sahara, Hironori; Nakasuka, Shinichi; Greenland, Stephen; Morimoto, Takeshi; Koyama, Kanichi; Kobayashi, Chisato; Kikuchi, Hideaki; Okada, Takanori; Tanaka, Hidenori

    2008-07-01

    This paper presents the current status, configuration, architecture, and key technologies of SOHLA-2, the demonstration mission of the PETSAT (Panel ExTension SATellite) concept. The PETSAT proposal is for a modular satellite consisting of any number of unfolding functional panels. These panels are designed around an open architecture and connected through standardized interfaces. The interfaces between panels incorporate a reliable "plug-in" format, such that when combined, the integrated system takes on the intended satellite function in a redundant and distributed manner. By combining the different panel types in any number and configuration, flexibility to mission requirements is achieved. Some panels for performing basic satellite functions will be available as commercial-off-the-shelf components, and others custom developed dependent on the mission. During launch these panels are stowed in a folded low volume configuration, which is then extended on-orbit, realizing a satellite with a large area for the mounting of solar arrays, mission systems, extensible booms, or any other components. SOHLA-2 is both a concept demonstration and a lightning detection mission in the VHF band. It weighs less than 50 kg and consists of six panels: communication, attitude control, propulsion, mission, experiment and bus function. The bus function panel is based on the successful Cubesat XI developed at the University of Tokyo and this acts as the manager of the technology demonstration aspects for the mission. By basing the architecture upon a proven technology, the reliability of the satellite is increased. It is intended that the satellite be launched in early 2008.

  18. Orbital Manoeuvres of Chinas Zi Yuan Satellites

    NASA Astrophysics Data System (ADS)

    Clark, P. S.

    China has launched two satellites in the Zi Yuan programme through to October 2001. The first was the CBERS satellite, developed jointly with Brazil and the second was a domestic satellite which is reportedly being used for reconnaissance work. The orbital behaviour of the two satellites has been completely different and is reviewed in this paper.

  19. Geostationary meteorological satellite systems - An overview

    NASA Astrophysics Data System (ADS)

    Blersch, Donald J.; Probert, Todd C.

    Past and present geosynchronous meteorological satellites developed in the USA, Europe, Japan, India, and the Soviet Union are reviewed. Particular attention is given to the Applications Technology Satellite Program, GOES and SMS/GOES, METEOSAT, GMS/Himawari, the Indian National Satellite, and a Soviet geostationary meteorological satellite program, GOMS.

  20. IMS/Satellite Situation Center report

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Services planned by the Satellite Situation Center during the International Magnetospheric Study are briefly described. User requirements are emphasized. The following data are presented: orbital parameters for ISIS 2, ESRO 4, and HEOS 2; entry exit times for highly elliptical satellites; plots for highly elliptical earth satellites; and plots and flux tube intersection for low altitude satellites.

  1. Satellites You Can See for Homework

    ERIC Educational Resources Information Center

    Broderick, Stephen

    2012-01-01

    Artificial satellites are easily observed most nights when the weather is fine. The website called "Heavens Above" at www.heavens-above.com will help locate these satellites flying over one's location. It also includes how bright they will appear. The direction of travel of each satellite in the night sky also indicates the type of satellite. For…

  2. Civil satellite navigation and location systems

    NASA Astrophysics Data System (ADS)

    Blanchard, W. F.

    1989-05-01

    The use of satellites for civil navigation and location, including satellites not necessarily launched for that purpose, is reviewed. In particular, attention is given to differences between civil and military satellites; civil use of military systems and the associated commercial considerations and regulatory issues; the use of communication satellites; and radiodetermination satellite service based on geostationary satellites. The discussion also covers integration with ground-based radio-navigation systems; existing radio-navigation satellite systems; and the Starfix, Geostar/Locstar, Starfind, Navsat, and Rexstar systems.

  3. Shadow imaging of geosynchronous satellites

    NASA Astrophysics Data System (ADS)

    Douglas, Dennis Michael

    Geosynchronous (GEO) satellites are essential for modern communication networks. If communication to a GEO satellite is lost and a malfunction occurs upon orbit insertion such as a solar panel not deploying there is no direct way to observe it from Earth. Due to the GEO orbit distance of ~36,000 km from Earth's surface, the Rayleigh criteria dictates that a 14 m telescope is required to conventionally image a satellite with spatial resolution down to 1 m using visible light. Furthermore, a telescope larger than 30 m is required under ideal conditions to obtain spatial resolution down to 0.4 m. This dissertation evaluates a method for obtaining high spatial resolution images of GEO satellites from an Earth based system by measuring the irradiance distribution on the ground resulting from the occultation of the satellite passing in front of a star. The representative size of a GEO satellite combined with the orbital distance results in the ground shadow being consistent with a Fresnel diffraction pattern when observed at visible wavelengths. A measurement of the ground shadow irradiance is used as an amplitude constraint in a Gerchberg-Saxton phase retrieval algorithm that produces a reconstruction of the satellite's 2D transmission function which is analogous to a reverse contrast image of the satellite. The advantage of shadow imaging is that a terrestrial based redundant set of linearly distributed inexpensive small telescopes, each coupled to high speed detectors, is a more effective resolved imaging system for GEO satellites than a very large telescope under ideal conditions. Modeling and simulation efforts indicate sub-meter spatial resolution can be readily achieved using collection apertures of less than 1 meter in diameter. A mathematical basis is established for the treatment of the physical phenomena involved in the shadow imaging process. This includes the source star brightness and angular extent, and the diffraction of starlight from the satellite

  4. Telemetry Data Collection from Oscar Satellite

    NASA Technical Reports Server (NTRS)

    Haddock, Paul C.; Horan, Stephen

    1998-01-01

    This paper discusses the design, configuration, and operation of a satellite station built for the Center for Space Telemetering and Telecommunications Laboratory in the Klipsch School of Electrical and Computer Engineering Engineering at New Mexico State University (NMSU). This satellite station consists of a computer-controlled antenna tracking system, 2m/70cm transceiver, satellite tracking software, and a demodulator. The satellite station receives satellite,telemetry, allows for voice communications, and will be used in future classes. Currently this satellite station is receiving telemetry from an amateur radio satellite, UoSAT-OSCAR-11. Amateur radio satellites are referred to as Orbiting Satellites Carrying Amateur Radio (OSCAR) satellites as discussed in the next section.

  5. Satellite services system analysis study. Volume 2: Satellite and services user model

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Satellite services needs are analyzed. Topics include methodology: a satellite user model; representative servicing scenarios; potential service needs; manned, remote, and automated involvement; and inactive satellites/debris. Satellite and services user model development is considered. Groundrules and assumptions, servicing, events, and sensitivity analysis are included. Selection of references satellites is also discussed.

  6. Jupiter small satellite montage

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A montage of images of the small inner moons of Jupiter from the camera onboard NASA's Galileo spacecraft shows the best views obtained of these moons during Galileo's 11th orbit around the giant planet in November 1997. At that point, Galileo was completing its first two years in Jupiter orbit--known as the Galileo 'prime mission'--and was about to embark on a successful two-year extension, called the Galileo Europa Mission.

    The top two images show the moon Thebe. Thebe rotates by approximately 50 degrees between the time these two images were taken, so that the same prominent impact crater is seen in both views; this crater, which has been given the provisional name Zethus, is near the point on Thebe that faces permanently away from Jupiter.

    The next two images show the moon Amalthea; they were taken with the Sun directly behind the observer, an alignment that emphasizes patterns of intrinsically bright or dark surface material. The third image from the top is a view of Amalthea's leading side, the side of the moon that 'leads' as Amalthea moves in its orbit around Jupiter. This image looks 'noisy' because it was obtained serendipitously during an observation of the Jovian satellite Io (Amalthea and Io shared the same camera frame but the image was exposed for bright Io rather than for the much darker Amalthea). The fourth image from the top emphasizes prominent 'spots' of relatively bright material that are located near the point on Amalthea that faces permanently away from Jupiter. The bottom image is a view of the tiny moon Metis.

    In all the images, north is approximately up, and the moons are shown in their correct relative sizes. The images are, from top to bottom: Thebe taken on November 7, 1997 at a range of 504,000 kilometers (about 313,000 miles); Thebe on November 7, 1997 at a range of 548,000 kilometers (about 340,000 miles); Amalthea on November 6, 1997 at a range of about 650,000 kilometers (about 404,000 miles); Amalthea on November

  7. Landscape Comparisons - Galilean Satellites

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This mosaic includes images taken by NASA's Galileo spacecraft during nine orbits around Jupiter and its four largest satellites. From left to right, the moons shown are Io, Europa, Ganymede, and Callisto. Galileo's solid state imaging camera built surface views in different colors and at varying resolutions. Most of the images were acquired between June 1996 and June 1997 by Galileo, but three images- Callisto in the top row, Ganymede in the middle row and Io in the bottom row-are from Voyager's mission to Jupiter in 1979.

    The top row displays the relative sizes of the moons in global views at relatively low resolution. The images, scaled to about 10 kilometers (3.9 miles) per picture element (pixel), feature the smallest visible features of about 20 kilometers (12.4 miles). Surfaces are affected by tectonic or volcanic changes in the moons' interiors or by exterior deposition. Middle row images show regional views of up to 10 times higher resolution, each covering an area about 1,000 by 750 kilometers (621 by 466 miles) and scaled to about 1.8 kilometer (1.1 mile) per pixel. Regional features include volcanic cauldera fields on Io, tidally-induced cracks thousands of kilometers long on Europa, bright grooved regions on Ganymede, and enormous impact basins on Callisto caused by impacts with primitive comets or asteroids. Bottom row views represent the highest resolutions, covering areas about 100 by 75 kilometers (62 by 47 miles) and scaled to about 180 meters (197 yards) per pixel. The images show Io's volcanic plume vents, Europa's abundant ridges, Ganymede's fractured, grooved terrain, and Callisto's heavily eroded and mantled craters.

    Spectral regions not visible to the eye are shown, indicating differences in surface chemical composition or changes in the way the surface reflects sunlight. For example, in the left middle image, bright red depicts newly-ejected volcanic material on Io, and the surrounding yellow materials are older sulphur deposits. The

  8. Search for Asteroid Satellites

    NASA Astrophysics Data System (ADS)

    Merline, W. J.; Close, L. M.; Menard, F.; Dumas, C.; Chapman, C. R.; Slater, D. C.

    2001-11-01

    We report on the recent progress of our comprehensive search for satellites of asteroids. In 1998, we began our survey using newly newly developed technologies in adaptive optics to explore the close environs of several hundred main-belt asteroids. Adaptive optics (AO) removes the blurring caused by the Earth's atmosphere and allows diffraction-limited imaging in the near-IR (J-,H-,K'-bands) at the world's largest telescopes. Angular resolutions as high as 0.04 arcsec are possible. We have employed the excellent facilities at the Canada-France-Hawaii Telescope, the W.M. Keck II telescope, and the new Gemini North 8m telescope. Each of these facilities provides unique capabilities and are each complementary to the other. So far we have discovered or recovered a half-dozen small moons or double asteroids by this AO-assisted direct-imaging technique. Our sample now exceeds 300 main-belt targets, and we have expanded the survey to include near-Earth and Trojan asteroids. Other groups are using AO, direct HST imaging, direct ground-based imaging, advanced lightcurve analysis, and radar techniques to further sample these populations, as well as the Kuiper Belt. Our results show that the frequency of binary asteroids (at least to our detection limits) is rather small in the main belt, possibly a few percent. Frequencies among other populations, such as the NEAs, are seen to be much higher. We also find that although there are similarities among the detected systems, there are also significant differences. Thus, it is likely that several different formation mechanisms will be required to explain the observed systems. All of the proposed mechanisms for formation involve collisions of one type or another (physical or gravitational). Study of these systems will provide significant insight to the collisional history and evolution of these asteroid populations. Further, the presence of a companion allows accurate determination of the density of the primary, and thus yields

  9. Oscar satellites, amateur radio in space

    NASA Astrophysics Data System (ADS)

    Henry, J. M.

    The history of amateur radio satellites is reviewed. Attention is given to the Canadian role in the development of the Orbiting Satellite Carrying Amateur Radio OSCAR payload carried aboard the Discoverer 36 satellite. Recent progress in developing new generation amateur radio satellites is addressed with reference to the AMSAT satellite which will retransmit emergency location transmitter signals from aircraft in distress. The position of the ELT is determined by computer processing of doppler information.

  10. 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.

  11. Linked Autonomous Interplanetary Satellite Orbit Navigation

    NASA Technical Reports Server (NTRS)

    Parker, Jeffrey S.; Anderson, Rodney L.; Born, George H.; Leonard, Jason M.; McGranaghan, Ryan M.; Fujimoto, Kohei

    2013-01-01

    A navigation technology known as LiAISON (Linked Autonomous Interplanetary Satellite Orbit Navigation) has been known to produce very impressive navigation results for scenarios involving two or more cooperative satellites near the Moon, such that at least one satellite must be in an orbit significantly perturbed by the Earth, such as a lunar halo orbit. The two (or more) satellites track each other using satellite-to-satellite range and/or range-rate measurements. These relative measurements yield absolute orbit navigation when one of the satellites is in a lunar halo orbit, or the like. The geometry between a lunar halo orbiter and a GEO satellite continuously changes, which dramatically improves the information content of a satellite-to-satellite tracking signal. The geometrical variations include significant out-of-plane shifts, as well as inplane shifts. Further, the GEO satellite is almost continuously in view of a lunar halo orbiter. High-fidelity simulations demonstrate that LiAISON technology improves the navigation of GEO orbiters by an order of magnitude, relative to standard ground tracking. If a GEO satellite is navigated using LiAISON- only tracking measurements, its position is typically known to better than 10 meters. If LiAISON measurements are combined with simple radiometric ground observations, then the satellite s position is typically known to better than 3 meters, which is substantially better than the current state of GEO navigation. There are two features of LiAISON that are novel and advantageous compared with conventional satellite navigation. First, ordinary satellite-to-satellite tracking data only provides relative navigation of each satellite. The novelty is the placement of one navigation satellite in an orbit that is significantly perturbed by both the Earth and the Moon. A navigation satellite can track other satellites elsewhere in the Earth-Moon system and acquire knowledge about both satellites absolute positions and velocities

  12. Minuteman 2 launched small satellite

    NASA Technical Reports Server (NTRS)

    Chan, Sunny; Hinders, Kriss; Martin, Trent; Mcmillian, Shandy; Sharp, Brad; Vajdos, Greg

    1994-01-01

    The goal of LEOSat Industries' Spring 1994 project was to design a small satellite that has a strong technology demonstration or scientific justification and incorporates a high level of student involvement. The satellite is to be launched into low earth orbit by the converted Minuteman 2 satellite launcher designed by Minotaur Designs, Inc. in 1993. The launch vehicle shroud was modified to a height of 90 inches, a diameter of 48 inches at the bottom and 35 inches at the top for a total volume of 85 cubic feet. The maximum allowable mass of the payload is about 1100 lb., depending on the launch site, orbit altitude, and inclination. The satellite designed by LEOSat Industries is TerraSat, a remote-sensing satellite that will provide information for use in space-based earth studies. It will consist of infrared and ultraviolet/visible sensors similar to the SDI-developed sensors being tested on Clementine. The sensors will be mounted on the Defense Systems, Inc. Standard Satellite-1 spacecraft bus. LEOSat has planned for two satellites orbiting the Earth with trajectories similar to that of LANDSAT 5. The semi-major axis is 7080 kilometers, the eccentricity is 0, and the inclination is 98.2 degrees. The estimated mass of TerraSat is 145 kilograms and the estimated volume is 1.8 cubic meters. The estimated cost of TerraSat is $13.7 million. The projected length of time from assembly of the sensors to launch of the spacecraft is 13 months.

  13. Weather Satellite Enterprise Information Chain

    NASA Astrophysics Data System (ADS)

    Jamilkowski, M. L.; Grant, K. D.; Miller, S. W.; Cochran, S.

    2015-12-01

    NOAA & NASA are acquiring the next-generation civilian operational weather satellite: Joint Polar Satellite System (JPSS). Contributing the afternoon orbit & ground system (GS) to replace current NOAA POES Satellites, its sensors will collect meteorological, oceanographic & climatological data. The JPSS Common Ground System (CGS), consisting of C3 and IDP segments, is developed by Raytheon. It now flies the Suomi National Polar-orbiting Partnership (S-NPP) satellite, transferring data between ground facilities, processing them into environmental products for NOAA weather centers, and expanding to support JPSS-1 in 2017. As a multi-mission system, CGS provides combinations of C3, data processing, and product delivery for numerous NASA, NOAA, DoD and international missions.The CGS provides a wide range of support to a number of missions: Command and control and mission management for the S-NPP mission today, expanding this support to the JPSS-1 satellite mission in 2017 Data acquisition for S-NPP, the JAXA's Global Change Observation Mission - Water (GCOM-W1), POES, and the Defense Meteorological Satellite Program (DMSP) and Coriolis/WindSat for the DoD Data routing over a global fiber network for S-NPP, JPSS-1, GCOM-W1, POES, DMSP, Coriolis/WindSat, NASA EOS missions, MetOp for EUMETSAT and the National Science Foundation Environmental data processing and distribution for S-NPP, GCOM-W1 and JPSS-1 The CGS plays a key role in facilitating the movement and value-added enhancement of data all the way from satellite-based sensor data to delivery to the consumers who generate forecasts and produce watches and warnings. This presentation will discuss the information flow from sensors, through data routing and processing, and finally to product delivery. It will highlight how advances in architecture developed through lessons learned from S-NPP and implemented for JPSS-1 will increase data availability and reduce latency for end user applications.

  14. Using Cell Phones From Satellites

    NASA Technical Reports Server (NTRS)

    Horan, Stephen

    2000-01-01

    During the past several years, an interest has grown in using commercial telecommunications techniques to supply Telemetry and Command (T&C) services. Recently, the National Aeronautics and Space Administration (NASA) Space Operations Management Office (SOMO) has outlined plans to utilize satellite-based telecommunications services to support space operations in space missions over the next several decades. NASA currently obtains the bulk of its telecommunications services for earth-orbiting satellites via the existing government-owned and controlled Space Network (SN) system. This system consists of the constellation of Tracking and Data Relay Satellites (TDRS) in Geostationary Earth Orbit (GEO) and the associated ground terminals and communications intrastructure. This system is valuable and effective for scientific satellites costing over one million dollars. However, for smaller satellites, this system becomes problematic due to the cost of transponders and support infrastructure. The nominal transponders for using the TDRS cannot be obtained for a cost in dollars, and size, weight, or power that the 3 Corner Satellite project can afford. For these types of nanosatellite missions, alternatives that fit the mission cost and satellite profiles are needed. In particular, low-cost access using existing commercial infrastructure would be useful to mission planners. In particular, the ability to obtain low data rate T&C services would be especially valuable. The nanosatellites generally have low T&C requirements and therefore would benefit from using commercial services that could operate in the 2400 bps - 9600 bps range, especially if contact times longer than the 5 - 10 minute ground station passes could be found.

  15. Autonomous satellite navigation methods using the Global Positioning Satellite System

    NASA Technical Reports Server (NTRS)

    Murata, M.; Tapley, B. D.; Schutz, B. E.

    1982-01-01

    This investigation considers the problem of autonomous satellite navigation using the NAVSTAR Global Positioning System (GPS). The major topics covered include the design, implementation, and validation of onboard navigation filter algorithms by means of computer simulations. The primary errors that the navigation filter design must minimize are computational effects and modeling inaccuracies due to limited capability of the onboard computer. The minimization of the effect of these errors is attained by applying the sequential extended Kalman filter using a factored covariance implementation with Q-matrix or dynamical model compensations. Peformance evaluation of the navigation filter design is carried out using both the CDC Cyber 170/750 computer and the PDP-11/60 computer. The results are obtained assuming the Phase I GPS constellation, consisting of six satellites, and a Landsat-D type spacecraft as the model for the user satellite orbit.

  16. Phoebe and the Icy Saturnian Satellites: Implications for Satellite Origins

    NASA Astrophysics Data System (ADS)

    Mosqueira, I.; Estrada, P. R.

    2004-11-01

    Phoebe's retrograde, eccentric and inclined orbit marks it as an object captured from heliocentric orbit. Accordingly, its composition may be indicative of its origin in the solar nebula. Analogous arguments have been made extensively in connection with the origin of Pluto-Charon (see, e.g., McKinnon et al. 1997) as well as Triton (McKinnon and Mueller 1989). Indeed, the demarcation between nebula and subnebula objects has led a number of workers (see, e.g., Johnson et al. 1987; Lunine et al. 1993; Podolak et al. 1993) to argue that the regular satellites of the giant planets did not derive the bulk of their material directly from heliocentric orbit. The recent Cassini flyby of Phoebe has yielded a mass for this object of GM = 0.5527 ± 0.001 km3/s2 Jacobson et al. 2004 (this conference). Its density of 1.6 g/cm3 indicates a rock to ice ratio of at least 50 % (Porco et al. 2004; Science, to be submitted). Phoebe's high rock/ice ratio when compared to the icy Saturnian satellites reinforces the argument that Phoebe is an object that formed in heliocentric orbit and became captured. Yet, given that it may be misleading to lump together satellites with quite different formation histories, we refine the comparison on the basis of models for regular satellite formation. Because it derives condensables directly from heliocentric orbit and fails to consider planetesimals, the model of Canup and Ward (2002) does not provide a context for understanding such compositional differences. We will therefore discuss two models of satellite formation we are developing, which differ mainly in their treatment of turbulence (decaying vs steady). In both models the inner (located inside Titan's orbit), icy Saturnian satellites represent a second generation of objects. Mosqueira and Estrada (2003a,b) has these satellites forming 104-10^5 years after Titan as the disk became optically thin and water rich due to preferential gas drag loss of silicates as Saturn cooled. On the other hand

  17. Phoebe and the Icy Saturnian Satellites: Implications for Satellite Origins

    NASA Astrophysics Data System (ADS)

    Mosqueira, I.; Estrada, P. R.

    2004-12-01

    Phoebe's retrograde, eccentric and inclined orbit marks it as an object captured from heliocentric orbit. Accordingly, its composition may be indicative of its origin in the solar nebula. Analogous arguments have been made extensively in connection with the origin of Pluto-Charon (see, e.g., McKinnon et al. 1997) as well as Triton (McKinnon and Mueller 1989). Indeed, the demarcation between nebula and subnebula objects has led a number of workers (see, e.g., Johnson et al. 1987; Lunine et al. 1993; Podolak et al. 1993) to argue that the regular satellites of the giant planets did not derive the bulk of their material directly from heliocentric orbit. The recent Cassini flyby of Phoebe has yielded a mass for this object of GM = 0.5527 ± 0.001 km3/s2 Jacobson et al. 2004. Its density of 1.6 g/cm3 indicates a rock to ice ratio of at least 50 % (Porco et al. 2004; Science, to be submitted). Phoebe's high rock/ice ratio when compared to the icy Saturnian satellites reinforces the argument that Phoebe is an object that formed in heliocentric orbit and became captured. Yet, given that it may be misleading to lump together satellites with quite different formation histories, we refine the comparison on the basis of models for regular satellite formation. Because it derives condensables directly from heliocentric orbit and fails to consider planetesimals, the model of Canup and Ward (2002) does not provide a context for understanding such compositional differences. We will therefore discuss two models of satellite formation we are developing, which differ mainly in their treatment of turbulence (decaying vs steady). In both models the inner (located inside Titan's orbit), icy Saturnian satellites represent a second generation of objects. Mosqueira and Estrada (2003a,b) has these satellites forming 104-10^5 years after Titan as the disk became optically thin and water rich due to preferential gas drag loss of silicates as Saturn cooled. On the other hand, the gas

  18. Automatic satellite tracking system for the NASA Satellite Photometric Observatory

    NASA Technical Reports Server (NTRS)

    Mucklow, Glenn H.

    1980-01-01

    The development of an Automatic TV Tracking System for NASA's mobile 61 cm aperture Satellite Photometric Observatory is described. The analysis techniques used to match the FOV and resolutions to changing seeing conditions are covered in details. Theoretical reasons for such matching of general interest are discussed. It is shown that the energy density in a satellite image is 11 times greater during good seeing conditions than during typical seeing conditions. The Z7987 image tube is shown to be able to detect 16th magnitude objects under ideal seeing conditions using only 8 percent of the light collected by the main telescope. Experimental results show that the SPO equipped with a Z7987 camera can track a satellite at any orbital velocity with less than 0.14 mr accuracy using the DBA Series 606 TV Tracker. The manual system used prior to the installation of the Automatic TV Tracking System could maintain track at 1.1 mr accuracy for comparison.

  19. Stream Gauges and Satellite Measurements

    NASA Astrophysics Data System (ADS)

    Alsdorf, D. E.

    2010-12-01

    Satellite measurements should not be viewed as a replacement for stream gauges. However, occasionally it is suggested that because satellite-based measurements can provide river discharge, a motivation for satellite approaches is an increasing lack of stream gauges. This is an argument for more stream gauges, but not necessarily for satellite measurements. Rather, in-situ and spaceborne methods of estimating discharge are complementary. Stream gauges provide frequent measurements at one point in the river reach whereas satellites have the potential to measure throughout all reaches but at orbital repeat intervals of days to weeks. The Surface Water and Ocean Topography satellite mission (SWOT) is an opportunity to further develop these complements. The motivation for SWOT, and indeed for any satellite based method of estimating discharge, should not be as a replacement for stream gauges. Scientific and application uses should motivate the measurements. For example, understanding floods with their dynamic water surfaces are best sampled from remote platforms that provide water surface elevations throughout the floodwave. As another example, today’s water and energy balance models are giving outputs at increasing spatial resolution and are making use of water surface elevations throughout the modeled basin. These models require a similar resolution in the calibrating and validating observations. We should also be aware of practical limitations. In addition to providing spatially distributed hydrodynamic measurements on rivers, SWOT will be able to measure storage changes in the estimated 30 million lakes in the world that are larger than a hectare. Knowing the storage changes in these lakes is especially important in certain regions such as the Arctic but gauging even a small fraction of these is impractical. Another motivator for satellite methods is that even in the presence of stream gauges, discharge data is not always well shared throughout all countries

  20. Research Supporting Satellite Communications Technology

    NASA Technical Reports Server (NTRS)

    Horan Stephen; Lyman, Raphael

    2005-01-01

    This report describes the second year of research effort under the grant Research Supporting Satellite Communications Technology. The research program consists of two major projects: Fault Tolerant Link Establishment and the design of an Auto-Configurable Receiver. The Fault Tolerant Link Establishment protocol is being developed to assist the designers of satellite clusters to manage the inter-satellite communications. During this second year, the basic protocol design was validated with an extensive testing program. After this testing was completed, a channel error model was added to the protocol to permit the effects of channel errors to be measured. This error generation was used to test the effects of channel errors on Heartbeat and Token message passing. The C-language source code for the protocol modules was delivered to Goddard Space Flight Center for integration with the GSFC testbed. The need for a receiver autoconfiguration capability arises when a satellite-to-ground transmission is interrupted due to an unexpected event, the satellite transponder may reset to an unknown state and begin transmitting in a new mode. During Year 2, we completed testing of these algorithms when noise-induced bit errors were introduced. We also developed and tested an algorithm for estimating the data rate, assuming an NRZ-formatted signal corrupted with additive white Gaussian noise, and we took initial steps in integrating both algorithms into the SDR test bed at GSFC.

  1. Petite Amateur Navy Satellite (PANSAT)

    NASA Technical Reports Server (NTRS)

    Sakoda, D.; Hiser, J. K.

    1989-01-01

    The Naval Postgraduate School's (NPS) Space Systems Academic Group (SSAG) is designing and developing a small communications satellite for launch aboard the shuttle as a complex autonomous payload (CAP). The objectives of PANSAT are three-fold. First, PANSAT will provide an ideal educational tool for the officer students at NPS supporting Space Systems Engineering and Space Systems Operations with hands-on hardware development. Second, the satellite will provide digital store-and-forward communications, or packet radio, for the amateur radio community. The third objective is to provide a low-cost, space-based platform for small experiments. PANSAT will be launched from the shuttle at a nominal altitude of 200 n.m. and an inclination of at least 37 degrees. The satellite weight is 150 lbs. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 437.25 MHz. A maximum 50 kHz of bandwidth is envisioned for the satellite. The expected lifetime of the satellite is 1 1/2 to 2 years before atmospheric reentry. The PANSAT design consists of the following: communications subsystem (COMM); computer, or data processor and sequencer (DP&S); power subsystem; structure subsystem; and experiment payload.

  2. VLBI observations of geosynchronous satellites

    NASA Astrophysics Data System (ADS)

    Shu, Fengchun; Zhang, Xiuzhong; Zheng, Weimin

    The principle of determining spacecraft angular position with differential VLBI (Very Long Baseline Interferometry) technique is described. The first domestic differential VLBI observations of geosynchronous satellites were performed with participations of Shanghai, Urumqi and Kunming stations. Three strong quasars within angular separation of 15° from target satellites were selected as reference radio sources. The main purpose of such observations is to obtain interferometric fringes of the satellites, and to estimate accuracy of differential VLBI observations. A 2-station FX type correlator at SHAO (Shanghai Astronomical Observatory) was used to do cross-correlations of radio signals in MK3A-C tape format. Strong fringes of the satellites were detected to all stations. The precision of time delay and rate was derived from the correlator output. Based on system errors analysis, we estimated that ΔDOR (Delta Differential One-way Ranging) error was about 41 cm, and ΔDOD (Delta Differential One-way Doppler) error was about 0.148mm/s, which corresponded, respectively, to the position error of 8m and the velocity error of 2.8mm/s for the geosynchronous satellite on the plane of sky.

  3. Satellite dual antenna pointing system

    NASA Technical Reports Server (NTRS)

    Keigler, John E. (Inventor); Hartshorne, Frank A. (Inventor)

    1986-01-01

    A satellite antenna pointing system for separately pointing separated transmit and receive high gain antenna systems includes means for separately and sequentially applying a beacon signal to the transmit and receive antenna systems and a broad beam width antenna which has a coverage area greater than the overall coverage region of the spot beam antenna systems. The system includes ground stations located at or near the periphery of the overall coverage region adapted to receive these beacon signals. At a central control station these beacon signals are compared to provide first signals proportional to the ratio of said beacon signals received from said transmit antenna system and said broad beam width antenna and second signals proportional to the ratio of said beacon signals received from said satellite receive antenna system and said broad beam width antenna. The central station generates from said first signals transmit antenna control signals which are sent to the satellite to control the orientation of said transmit antenna system. Likewise, the central control station generates from the second signals receiver antenna control signals which are applied to the satellite to control the orientation of the satellite receive antenna system.

  4. 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.

  5. Chartering Launchers for Small Satellites

    NASA Astrophysics Data System (ADS)

    Hernandez, Daniel

    The question of how to launch small satellites has been solved over the years by the larger launchers offering small satellites the possibility of piggy-backing. Specific fixtures have been developed and commercialized: Arianespace developed the ASAP interface, the USAF studied ESPA, NASA has promoted Shuttle launch possibilities, Russian authorities and companies have been able to find solutions with many different launchers... It is fair to say that most launcher suppliers have worked hard and finally often been able to find solutions to launch most small satellites into orbit. It is also true, however, that most of these small satellites were technology demonstration missions capable of accepting a wide range of orbit and launch characteristics: orbit altitude and inclination, launch date, etc. In some cases the small satellite missions required a well-defined type of orbit and have therefore been obliged to hire a small launcher on which they were the prime passenger. In our paper we would like to propose an additional solution to all these possibilities: launchers could plan well in advance (for example about 3 years), trips to precisely defined orbits to allow potential passengers to organize themselves and be ready on the D-Day. On the scheduled date the chartered launcher goes to the stated orbit while on another date, another chartered launcher goes to another orbit. The idea is to organize departures for space like trains or airplanes leaving on known schedules for known destinations.

  6. Visualizing Airborne and Satellite Imagery

    NASA Technical Reports Server (NTRS)

    Bierwirth, Victoria A.

    2011-01-01

    Remote sensing is a process able to provide information about Earth to better understand Earth's processes and assist in monitoring Earth's resources. The Cloud Absorption Radiometer (CAR) is one remote sensing instrument dedicated to the cause of collecting data on anthropogenic influences on Earth as well as assisting scientists in understanding land-surface and atmospheric interactions. Landsat is a satellite program dedicated to collecting repetitive coverage of the continental Earth surfaces in seven regions of the electromagnetic spectrum. Combining these two aircraft and satellite remote sensing instruments will provide a detailed and comprehensive data collection able to provide influential information and improve predictions of changes in the future. This project acquired, interpreted, and created composite images from satellite data acquired from Landsat 4-5 Thematic Mapper (TM) and Landsat 7 Enhanced Thematic Mapper plus (ETM+). Landsat images were processed for areas covered by CAR during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCT AS), Cloud and Land Surface Interaction Campaign (CLASIC), Intercontinental Chemical Transport Experiment-Phase B (INTEXB), and Southern African Regional Science Initiative (SAFARI) 2000 missions. The acquisition of Landsat data will provide supplemental information to assist in visualizing and interpreting airborne and satellite imagery.

  7. Space Solar Power: Satellite Concepts

    NASA Technical Reports Server (NTRS)

    Little, Frank E.

    1999-01-01

    Space Solar Power (SSP) applies broadly to the use of solar power for space related applications. The thrust of the NASA SSP initiative is to develop concepts and demonstrate technology for applying space solar power to NASA missions. Providing power from satellites in space via wireless transmission to a receiving station either on earth, another celestial body or a second satellite is one goal of the SSP initiative. The sandwich design is a satellite design in which the microwave transmitting array is the front face of a thin disk and the back of the disk is populated with solar cells, with the microwave electronics in between. The transmitter remains aimed at the earth in geostationary orbit while a system of mirrors directs sunlight to the photovoltaic cells, regardless of the satellite's orientation to the sun. The primary advantage of the sandwich design is it eliminates the need for a massive and complex electric power management and distribution system for the satellite. However, it requires a complex system for focusing sunlight onto the photovoltaic cells. In addition, positioning the photovoltaic array directly behind the transmitting array power conversion electronics will create a thermal management challenge. This project focused on developing designs and finding emerging technology to meet the challenges of solar tracking, a concentrating mirror system including materials and coatings, improved photovoltaic materials and thermal management.

  8. Satellite remote sensing. An introduction

    SciTech Connect

    Harris, R.

    1987-01-01

    Satellite remote sensing, which is the monitoring, evaluation and prediction of the resources and features of the Earth's surface and its atmosphere from satellites, is an exciting, fast-growing technique used by environmental scientists to improve their knowledge of our planet. The non-military and non-communications satellites launched by the US, USSR, and the European Community produce digital images of the Earth's surface and its atmosphere. These images are used to search for undiscovered mineral resources, to conduct population, land use and resource censuses, to control pests and pollution, to illustrate weather movements on television and much more. This introductory book examines the physical basis of remote sensing-the sensors and satellites used to collect data, and the methods used to process these data as well as the application of satellite remote sensing in the study of vegetation, land use, geology, soils, the atmosphere and the hydrosphere. The last chapter looks at the future: space stations, international coordination, etc.

  9. Galilean satellite eclipse studies. I - Observations and satellite characteristics

    NASA Technical Reports Server (NTRS)

    Greene, T. F.; Smith, D. W.; Shorthill, R. W.

    1980-01-01

    Spectrophotometric light curves of 12 Galilean satellite eclipses are reported. The observations were made in 20 to 30 channels over the wavelength range 3240 to 10,500 A using the 200-in. telescope. The initial data processing is described. These data measure the Jovian aerosol content in the lower stratosphere and uppermost troposphere and the methane abundance in the lower stratosphere. The data are consistent with a lack of limb darkening on the Galilean satellites. The orbit of Callisto is shown to be inclined 0.08 + or - 0.02 deg to the equatorial plane of Jupiter.

  10. Domestic and regional satellite systems

    NASA Astrophysics Data System (ADS)

    Keigler, John E.; Profera, Charles E.

    1990-07-01

    The technical characteristics of domestic and regional satellite systems are discussed. Spacecraft technology is reviewed, communication payload technology developments are discussed, and resources and economics are discussed. It is seen that, compared to the installation of terrestrial microwave or optical cable networks in remote and harsh areas, satellite systems offer both lower costs and shorter time to bring on line. Proven technology and mature hardware is available for regions where orbit/spectrum space is still plentiful. As in North America, the sequence of growth is likely to be C-band and then K-band. Corresponding earth station advances in efficient modulation techniques and time-division multiple access will increase the capacity per transponder channel, while frequency and spatial reuse will provide more channels per satellite.

  11. The Mexican national satellite system

    NASA Astrophysics Data System (ADS)

    Sanchez Ruiz, M. E.; Briskman, R. D.

    1983-10-01

    The satellites, tracking, telemetry, command, and monitoring facilities, and the earth station complex for the Mexican national satellite system, Morelos, are described. The spacecraft are intended to provide educational television, rural telephony, data transmission, and business and industrial services. Scheduled for 1985 launch, the satellites will be placed in GEO and use the C and Ku bands with 12 narrow band and six wideband transponders. Spin-stabilized and solar cell powered, the functional mass will be 666 kg, including propellant. The solar panels will provide 940 W of power and 830 W will be available from NiCd batteries during eclipse conditions. The earth station will be located at Iztapalapa, which will have a 12 m antenna, redundant uplink and downlink radios, and command and ranging equipment. Back-up capability will be provided by a station at Tulancingo. Ku band and C band stations are in planning.

  12. General relativity and satellite orbits

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.

    1975-01-01

    The general relativistic correction to the position of a satellite is found by retaining Newtonian physics for an observer on the satellite and introducing a potential. The potential is expanded in terms of the Keplerian elements of the orbit and substituted in Lagrange's equations. Integration of the equations shows that a typical earth satellite with small orbital eccentricity is displaced by about 17 cm. from its unperturbed position after a single orbit, while the periodic displacement over the orbit reaches a maximum of about 3 cm. The moon is displaced by about the same amounts. Application of the equations to Mercury gives a total displacement of about 58 km. after one orbit and a maximum periodic displacement of about 12 km.

  13. PLHR emissions observed on satellites

    NASA Astrophysics Data System (ADS)

    Molchanov, Oleg; Parrot, Michel

    1995-04-01

    The aim of this paper is to review the most relevant characteristics of Power Line Harmonic Radiation (PLHR) that have been observed from satellites. Fifteen years ago, just after publications of results from the ARIEL-3 and -4 satellites, a large debate occurred about the influence of this phenomenon on natural wave emissions. New data were recently published concerning observations made from the low-altitude satellite AUREOL-3. These data indicate strong evidence for man-made influences on the ionosphere and magnetosphere. All the previous observations will be presented, with their main features. This paper also discusses the possible origin of magnetospheric lines that have been reported. The influence of man-made emissions will be evaluated and compared with other sources of energy in the Earth's environment.

  14. Radiodetermination satellite services and standard

    NASA Astrophysics Data System (ADS)

    Rothblatt, Martin A.

    Technical and operational aspects of radiodetermination satellite services (RDSSs) are examined in a general overview. RDSS is the satellite position-finding and navigation service (with limited alphanumeric message capability) defined by the FCC and ITU for operation at 1.610-1.626 GHz (uplink) and 2.484-2.500 GHz (downlink). The history of RDSS and its relationship to other satellite communication systems are discussed, and consideration is given to RDSS system architectures; space-segment, control-segment, and user-segment design; traffic management and control of non-RDSS interference; and aeronautical, maritime, land-mobile, personal, and special RDSS applications. Diagrams, graphs, and tables of numerical data are provided.

  15. Gaussian entanglement distribution via satellite

    NASA Astrophysics Data System (ADS)

    Hosseinidehaj, Nedasadat; Malaney, Robert

    2015-02-01

    In this work we analyze three quantum communication schemes for the generation of Gaussian entanglement between two ground stations. Communication occurs via a satellite over two independent atmospheric fading channels dominated by turbulence-induced beam wander. In our first scheme, the engineering complexity remains largely on the ground transceivers, with the satellite acting simply as a reflector. Although the channel state information of the two atmospheric channels remains unknown in this scheme, the Gaussian entanglement generation between the ground stations can still be determined. On the ground, distillation and Gaussification procedures can be applied, leading to a refined Gaussian entanglement generation rate between the ground stations. We compare the rates produced by this first scheme with two competing schemes in which quantum complexity is added to the satellite, thereby illustrating the tradeoff between space-based engineering complexity and the rate of ground-station entanglement generation.

  16. Commercial applications of satellite oceanography

    NASA Technical Reports Server (NTRS)

    Montgomery, D. R.

    1981-01-01

    It is shown that in the next decade the oceans' commercial users will require an operational oceanographic satellite system or systems capable of maximizing real-time coverage over all ocean areas. Seasat studies suggest that three spacecraft are required to achieve this. Here, the sensor suite would measure surface winds, wave heights (and spectral energy distribution), ice characteristics, sea-surface temperature, ocean colorimetry, height of the geoid, salinity, and subsurface thermal structure. The importance of oceanographic data being distributed to commercial users within two hours of observation time is stressed. Also emphasized is the importance of creating a responsive oceanographic satellite data archive. An estimate of the potential dollar benefits of such an operational oceanographic satellite system is given.

  17. Dynamics of coorbital satellite rings

    NASA Technical Reports Server (NTRS)

    Salo, H.; Yoder, C. F.

    1988-01-01

    The dynamical behavior of a coorbital satellite ring is studied for N = 2-9 satellites, in terms of a simplified dynamical description, in which the motion is reduced to the separation angles between satellites. The number and stability of different kinds of stationary configurations is explored, revealing that equally spaced rings are not stable against small perturbations for N not greater than 6, while for N = 2-8 there exists another, stable compact solution. Integrations of exact equations confirm these results. Moreover, the systems are found to display chaotic characteristics for a certain range of energy. The behavior can be interpreted in terms of maximum velocity curves, defining the allowed region of the motion in the phase space.

  18. Advanced Communications Technology Satellite (ACTS)

    NASA Technical Reports Server (NTRS)

    Plecity, Mark S.; Nall, Mark E.

    1991-01-01

    The NASA Advanced Communications Technology Satellite (ACTS) provides high risk technologies having the potential to dramatically enhance the capabilities of the satellite communications industry. This experimental satellite, which will be launched by NASA in 1993, will furnish the technology necessary for providing a range of services. Utilizing the ACTS very-high-gain-hopping spot-beam antennas with on-board routing and processing, Very Small Aperture Terminal (VSAT) digital networks which provide on-demand, full-mesh-convectivity 1.544-MBPS services with only a single hop can be established. The high-gain spot-beam antenna at Ka-band permits wide area, flexible networks providing high data rate services between modest-size earth terminals.

  19. Satellite Communications Using Commercial Protocols

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.; Griner, James H.; Dimond, Robert; Frantz, Brian D.; Kachmar, Brian; Shell, Dan

    2000-01-01

    NASA Glenn Research Center has been working with industry, academia, and other government agencies in assessing commercial communications protocols for satellite and space-based applications. In addition, NASA Glenn has been developing and advocating new satellite-friendly modifications to existing communications protocol standards. This paper summarizes recent research into the applicability of various commercial standard protocols for use over satellite and space- based communications networks as well as expectations for future protocol development. It serves as a reference point from which the detailed work can be readily accessed. Areas that will be addressed include asynchronous-transfer-mode quality of service; completed and ongoing work of the Internet Engineering Task Force; data-link-layer protocol development for unidirectional link routing; and protocols for aeronautical applications, including mobile Internet protocol routing for wireless/mobile hosts and the aeronautical telecommunications network protocol.

  20. Schuler Period in LEO Satellites

    NASA Technical Reports Server (NTRS)

    Carpenter, Russell J.; Bar-Itzhack, Itzhack Y.

    2004-01-01

    This paper generalizes and extends the concept of the Schuler oscillation that occurs in the theory of inertial navigation systems, allowing one to see how the Schuler phenomenon affects inertial navigation systems operating in space. We show why a low earth orbit satellite's orbital period is identical to the period of the Schuler pendulum, which is the period of the errors for terrestrial inertial navigation systems. We also show that the generalized form of the Schuler oscillation takes the same form as the Hill-Clohessy-Wiltshire equations for satellite relative motion and that the period of the out-of-plane motion in neighboring satellite relative trajectories is the same as the Schuler period. Finally, we describe how INS gyro drift manifests itself in different coordinate systems for the orbital case. These results may assist orbital flight dynamics and attitude control systems engineers in the design and analysis of INS-equipped spacecraft

  1. Satellite Data Transmission (SDT) requirement

    NASA Technical Reports Server (NTRS)

    Chie, C. M.; White, M.; Lindsey, W. C.

    1984-01-01

    An 85 Mb/s modem/codec to operate in a 34 MHz C-band domestic satellite transponder at a system carrier to noise power ratio of 19.5 dB is discussed. Characteristics of a satellite channel and the approach adopted for the satellite data transmission modem/codec selection are discussed. Measured data and simulation results of the existing 50 Mbps link are compared and used to verify the simulation techniques. Various modulation schemes that were screened for the SDT are discussed and the simulated performance of two prime candidates, the 8 PSK and the SMSK/2 are given. The selection process that leads to the candidate codec techniques are documented and the technology of the modem/codec candidates is assessed. Costs of the modems and codecs are estimated.

  2. Natural Satellite Ephemerides at JPL

    NASA Astrophysics Data System (ADS)

    Jacobson, Robert Arthur; Brozovic, Marina

    2015-08-01

    There are currently 176 known natural planetary satellites in the solar system; 150 are officially recognized by the IAU and 26 have IAU provisional designations. We maintain ephemerides for all of the satellites at NASA's Jet Propulsion Laboratory (JPL) and make them available electronically through the On-Line Solar System Data Service known as Horizons(http://ssd.jpl.nasa.gov/horizons) and in the form of generic Spice Kernels (SPK files) from NASA's Navigation and Ancillary Information Facility (http://naif.jpl.nasa.gov/naif). General satellite information such as physical constants and descriptive orbital elements can be found on the JPL Solar System Dynamics Website (http://ssd.jpl.nasa.gov). JPL's ephemerides directly support planetary spacecraft missions both in navigation and science data analysis. They are also used in general scientific investigations of planetary systems. We produce the ephemerides by fitting numerically integrated orbits to observational data. Our model for the satellite dynamics accounts for the gravitational interactions within a planetary system and the external gravitational perturbations from the Sun and planets. We rely on an extensive data set to determine the parameters in our dynamical models. The majority of the observations are visual, photographic, and CCD astrometry acquired from Earthbased observatories worldwide and the Hubble Space Telescope. Additional observations include optical and photoelectric transits, eclipses, occultations, Earthbased radar ranging, spacecraft imaging,and spacecraft radiometric tracking. The latter data provide information on the planet and satellite gravity fields as well as the satellite position at the times of spacecraft close encounters. In this paper we report on the status of the ephemerides and our plan for future development, specifically that in support of NASA's Juno, Cassini, and New Horizons missions to Jupiter, Saturn, and Pluto, respectively.

  3. Reinventing the Solar Power Satellite

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.

    2004-01-01

    The selling price of electrical power varies with time. The economic viability of space solar power is maximum if the power can be sold at peak power rates, instead of baseline rate. Price and demand of electricity was examined from spot-market data from four example markets: New England, New York City, suburban New York, and California. The data was averaged to show the average price and demand for power as a function of time of day and time of year. Demand varies roughly by a factor of two between the early-morning minimum demand, and the afternoon maximum; both the amount of peak power, and the location of the peak, depends significantly on the location and the weather. The demand curves were compared to the availability curves for solar energy and for tracking and non-tracking satellite solar power systems in order to compare the market value of terrestrial and solar electrical power. In part 2, new designs for a space solar power (SSP) system were analyzed to provide electrical power to Earth for economically competitive rates. The approach was to look at innovative power architectures to more practical approaches to space solar power. A significant barrier is the initial investment required before the first power is returned. Three new concepts for solar power satellites were invented and analyzed: a solar power satellite in the Earth-Sun L2 point, a geosynchronous no-moving parts solar power satellite, and a nontracking geosynchronous solar power satellite with integral phased array. The integral-array satellite had several advantages, including an initial investment cost approximately eight times lower than the conventional design.

  4. Satellite-Based Quantum Communications

    SciTech Connect

    Hughes, Richard J; Nordholt, Jane E; McCabe, Kevin P; Newell, Raymond T; Peterson, Charles G

    2010-09-20

    Single-photon quantum communications (QC) offers the attractive feature of 'future proof', forward security rooted in the laws of quantum physics. Ground based quantum key distribution (QKD) experiments in optical fiber have attained transmission ranges in excess of 200km, but for larger distances we proposed a methodology for satellite-based QC. Over the past decade we have devised solutions to the technical challenges to satellite-to-ground QC, and we now have a clear concept for how space-based QC could be performed and potentially utilized within a trusted QKD network architecture. Functioning as a trusted QKD node, a QC satellite ('QC-sat') could deliver secret keys to the key stores of ground-based trusted QKD network nodes, to each of which multiple users are connected by optical fiber or free-space QC. A QC-sat could thereby extend quantum-secured connectivity to geographically disjoint domains, separated by continental or inter-continental distances. In this paper we describe our system concept that makes QC feasible with low-earth orbit (LEO) QC-sats (200-km-2,000-km altitude orbits), and the results of link modeling of expected performance. Using the architecture that we have developed, LEO satellite-to-ground QKD will be feasible with secret bit yields of several hundred 256-bit AES keys per contact. With multiple ground sites separated by {approx} 100km, mitigation of cloudiness over any single ground site would be possible, potentially allowing multiple contact opportunities each day. The essential next step is an experimental QC-sat. A number of LEO-platforms would be suitable, ranging from a dedicated, three-axis stabilized small satellite, to a secondary experiment on an imaging satellite. to the ISS. With one or more QC-sats, low-latency quantum-secured communications could then be provided to ground-based users on a global scale. Air-to-ground QC would also be possible.

  5. Morelos Satellite System for Mexico

    NASA Astrophysics Data System (ADS)

    Sanchez Ruiz, M. E.

    1986-03-01

    The telephone, television, and data communication services that the Morelos Satellite System (MSS) provides are discussed. The design and functions of the MSS which consists of two geosynchronous communication satellites that operate in C and Ku frequency bands and are located at 113.5 deg and 116.5 deg W longitude are described. The capabilities of the antenna, communication, attitude control, telemetry, command, reaction control, electrical power, and thermal control subsystems are studied. The components of the earth station are examined. The economic and social benefits possible from the application of the MSS to banking, rural clinics, food distribution services, and the oil and electric industries are analyzed.

  6. Environmentally induced discharges on satellites

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.

    1982-01-01

    The problem of assessing hazards to geosynchronous satellite systems from geomagnetic substorm encounters is investigated. The available space flight data, coupled with analytical modeling studies, show that only relatively low differential charging is possible from environmental encounters. Using an analytical study of a discharge event on SCATHA, a discharge process is postulated where a small amount of charge is lost to space. These characteristics could then be used as inputs to a coupling model to determine the hazard to a spacecraft. The procedure is applied to a three axis stabilized satellite design.

  7. Dimensioning of Aeronautical Satellite Services

    NASA Astrophysics Data System (ADS)

    Holzbock, M.; Jahn, A.; Werner, M.

    2002-01-01

    This paper will provide a generalised baseline for a systematic AirCom design process and address in particular the dimensioning of satellite systems for aeronautical services. These services will roll out soon in medium- and long-haul aircraft. The offered services will range from low rate telephony, internet access, and streaming applications for video and audio. The aggregate bit rates on up- and downlink will certainly be statistically time-dependent and asymmetric in forward and backward direction. A tool will be described that is able to model this traffic. Furthermore the dimensioning of satellite constellations can be done. Due to the stochastic nature of the traffic, multi-service models for the traffic generation of different services will be described. Furthermore, the traffic will be affected by the available bit rate and shaping or blocking will equalize the peak loads. If fleets with many aircraft are considered, aeronautical traffic models must be based on actual aircraft routes, flight schedules, location and time of day, as well as seats per aircraft and type of aircraft (charter, business etc.). The regionally distributed traffic has to be served by several satellites and appropriate sharing of the serving satellites may spread the traffic in hot zones and yield a better load distribution. When aeronautical services will spread out, the capacity demand will grow quickly and the capacity of existing Ku-band GEO satellites will soon be exceeded. Changing to higher frequency bands will provide large spectrum portions and smaller spotbeams will allow better frequency reuse. Even constellations with non-geostationary satellites could be re-advent to serve better the higher latitude regions. Then, another mobility component for the fast changing satellite topology need to be addressed, and routing issues of the traffic must be considered. The paper will describe solutions for the mapping of satellites and traffic demand as well as routing algorithms

  8. Land mobile satellite propagation results

    NASA Technical Reports Server (NTRS)

    Nicholas, David C.

    1988-01-01

    During the Fall of 1987 a land mobile satellite demonstration using the MARECS B2 satellite at 26 degrees W was performed. While all the data have not been digested, some observations are in order. First, the system worked remarkably well for the margins indicated. Second, when the system worked poorly, the experimenters could almost always identify terrain or other obstacles causing blockage. Third, the forward link seems relatively more reliable than the return link, and occasional return link problems occured which have not been entirely explained.

  9. Satellite imagery of the earth

    USGS Publications Warehouse

    Merifield, P.M.; Cronin, J.; Foshee, L.L.; Gawarecki, S.J.; Neal, J.T.; Stevenson, R.E.; Stone, R.O.; Williams, R.S., Jr.

    1969-01-01

    Photography of the Earth from spacecraft has application to both atmospheric and Earth sciences. Gemini and Apollo photographs have furnished information on sea surface roughness, areas of potential upwelling and oceanic current systems. Regional geologic structures and geomorphologic features are also recorded in orbital photographs. Infrared satellite imagery provides meteorological and hydrological data and is potentially useful for locating fresh water springs along coastal areas, sources of geothermal power and volcanic activity. Ground and airborne surveys are being undertaken to create a basis for the interpretation of data obtained from future satellite systems.

  10. Small satellite solar array substrate

    NASA Technical Reports Server (NTRS)

    Fiore, John N.; Rosanova, Giulio

    1994-01-01

    The SMall EXplorer (SMEX) Fast Auroral SnapshoT (FAST) spacecraft was developed to investigate plasma physics of auroral phenomena at high orbital altitude. The FAST satellite comprises a variety of deployable booms with sensors on the ends, and instruments that protrude from the main body of the spacecraft to obtain the plasma and electromagnetic fields data. This required the plasma disturbance around the satellite to be kept to a minimum. A non deployable, body mounted solar array was implemented. This led to the design of a light weight solar array substrate with a high degree of structural integrity.

  11. Ion propulsion for communications satellites

    NASA Technical Reports Server (NTRS)

    Poeschel, R. L.

    1984-01-01

    In a recent study of potential applications for electric propulsion, it was determined that ion propulsion can provide North-South stationkeeping (NSSK) for communication satellites in geosynchronous orbit with appreciably less mass than chemical propulsion. While this finding is not new, the margin of benefit over advanced chemical propulsion technology depends strongly on the ion propulsion system specifications. Full advantage must be taken of the under-utilized stored energy available from the communication satellite's batteries. This paper describes a methodology for evaluating the benefits obtained in using ion propulsion for NSSK, both in terms of the mass reduction and its economic value.

  12. Chameleon gravity and satellite geodesy

    NASA Astrophysics Data System (ADS)

    Morris, J. R.

    2014-12-01

    We consider the possibility of the detection of a chameleon effect by an earth orbiting satellite such as LAGEOS, and possible constraints that might be placed on chameleon model parameters. Approximate constraints presented here result from using a simple monopole approximation for the gravitational field of the earth, along with results from the Khoury-Weltman chameleon model, solar system constraints obtained from the Cassini mission, and parameter bounds obtained from the LAGEOS satellite. It is furthermore suggested that a comparison of ground-based and space-based multipole moments of the geopotential could reveal a possible chameleon effect.

  13. Data compression for satellite images

    NASA Technical Reports Server (NTRS)

    Chen, P. H.; Wintz, P. A.

    1976-01-01

    An efficient data compression system is presented for satellite pictures and two grey level pictures derived from satellite pictures. The compression techniques take advantages of the correlation between adjacent picture elements. Several source coding methods are investigated. Double delta coding is presented and shown to be the most efficient. Both predictive differential quantizing technique and double delta coding can be significantly improved by applying a background skipping technique. An extension code is constructed. This code requires very little storage space and operates efficiently. Simulation results are presented for various coding schemes and source codes.

  14. Customer concerns regarding satellite servicing

    NASA Technical Reports Server (NTRS)

    Rysavy, Gordon

    1987-01-01

    The organization of orbital servicing of satellites is discussed. Provision of servicing equipment; design interfaces between the satellite and the servicing equipment; and the economic viability of the concept are discussed. The proposed solution for satisfying customer concerns is for the servicing organizations to baseline an adequate inventory of servicing equipment with standard interfaces and established servicing costs. With this knowledge, the customer can conduct tradeoff studies and make programmatic decisions regarding servicing options. A dialog procedure between customers and servicing specialists is outlined.

  15. Severe storms observing satellite (STORMSAT)

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The primary payload for this satellite is the Advanced Atmospheric Sounding and Imaging Radiometer which will perform precise infrared temperature sounding and visible/infrared imaging from geostationary orbit. A secondary payload instrument which may be utilized on STORMSAT is the Microwave Atmospheric Sounding Radiometer which provides an independent set of temperature and humidity sounding in cloudy, meteorologically active regions. The study provides satellite designs and identifies mission-unique subsystems using the Multimission Modular Spacecraft using a Shuttle/Interim Upper Stage launch vehicle.

  16. The economics of satellite maintenance

    NASA Technical Reports Server (NTRS)

    Derocher, W. L., Jr.; Sosnay, R. G.

    1975-01-01

    The primary goal of the space transportation system - to reduce the cost of space programs while satisfying their mission requirements - can be enhanced by the proper choice of a satellite-maintenance concept. This paper develops the life-cycle costs of performing an automated satellite program during the shuttle era in three competitive modes: expendable, ground-refurbishable, and in-orbit maintainable. In-orbit maintenance is shown to be the most economic maintenance mode for both low- and high-earth orbits.

  17. Trends in NASA communication satellites

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.; Robbins, W. H.; Stretchberry, D. M.

    1972-01-01

    Satellite telecommunications can help to satisfy several national needs such as education, health care, cultural opportunities, and data transfer. There are current experiments being conducted with NASA spacecraft ATS 1, 3, and 5 in an attempt to satisfy these national needs. Future experiments are planned for the ATS F/G and CTS spacecrafts. The next generation of communications satellites must provide multiple region coverage, multichannel capability, high quality TV pictures, and must allow low cost ground receivers to be used. The proposed NASA spacecrafts, ATS H/I, will satisfy these requirements. Other countries of the world can benefit from ATS H/I technology.

  18. NASA's mobile satellite development program

    NASA Technical Reports Server (NTRS)

    Rafferty, William; Dessouky, Khaled; Sue, Miles

    1988-01-01

    A Mobile Satellite System (MSS) will provide data and voice communications over a vast geographical area to a large population of mobile users. A technical overview is given of the extensive research and development studies and development performed under NASA's mobile satellite program (MSAT-X) in support of the introduction of a U.S. MSS. The critical technologies necessary to enable such a system are emphasized: vehicle antennas, modulation and coding, speech coders, networking and propagation characterization. Also proposed is a first, and future generation MSS architecture based upon realized ground segment equipment and advanced space segment studies.

  19. Providing satellite systems for the national weather satellite services.

    NASA Technical Reports Server (NTRS)

    Stroud, W. G.; Press, H.; Stampfl, R. A.

    1973-01-01

    Discussion of cooperative arrangements and agreements among NASA, the Department of Commerce, and other governmental agencies in developing and operating meteorological satellite systems. The development of present interagency agreements and their conditions are discussed along with differences from the usual NASA program introduced by the supplier-client relationship between NASA and NOAA (National Oceanic and Atmospheric Administration).

  20. Ocean observing satellite study: instrument and satellite constellation architecture options

    NASA Technical Reports Server (NTRS)

    Gerber, A. J.; McGuire, J.; Cunningham, J. D.; Pichel, W. G.

    2002-01-01

    This paper provides: (1) an overview of the set of active and passive instruments identified by the IPO designed to make the ocean measurements including visible and infrared medium and high resolution imagers, radiometers, altimeters, and synthetic aperture radars and (2) the instrument and satellite constellation architecture options studied, and their ability to meet the set of measurement requirements.

  1. Satellite switched FDMA advanced communication technology satellite program

    NASA Technical Reports Server (NTRS)

    Atwood, S.; Higton, G. H.; Wood, K.; Kline, A.; Furiga, A.; Rausch, M.; Jan, Y.

    1982-01-01

    The satellite switched frequency division multiple access system provided a detailed system architecture that supports a point to point communication system for long haul voice, video and data traffic between small Earth terminals at Ka band frequencies at 30/20 GHz. A detailed system design is presented for the space segment, small terminal/trunking segment at network control segment for domestic traffic model A or B, each totaling 3.8 Gb/s of small terminal traffic and 6.2 Gb/s trunk traffic. The small terminal traffic (3.8 Gb/s) is emphasized, for the satellite router portion of the system design, which is a composite of thousands of Earth stations with digital traffic ranging from a single 32 Kb/s CVSD voice channel to thousands of channels containing voice, video and data with a data rate as high as 33 Mb/s. The system design concept presented, effectively optimizes a unique frequency and channelization plan for both traffic models A and B with minimum reorganization of the satellite payload transponder subsystem hardware design. The unique zoning concept allows multiple beam antennas while maximizing multiple carrier frequency reuse. Detailed hardware design estimates for an FDMA router (part of the satellite transponder subsystem) indicate a weight and dc power budget of 353 lbs, 195 watts for traffic model A and 498 lbs, 244 watts for traffic model B.

  2. Emerging technologies for communication satellite payloads

    NASA Astrophysics Data System (ADS)

    Yüceer, Mehmet

    2012-04-01

    Recent developments in payload designs will allow more flexible and efficient use of telecommunication satellites. Important modifications in repeater designs, antenna structures and spectrum policies open up exciting opportunities for GEO satellites to support a variety of emerging applications, ranging from telemedicine to real-time data transfer between LEO satellite and ground station. This study gives information about the emerging technologies in the design of communication satellites' transceiver subsystem and demonstrates the feasibility of using fiber optic links for the local oscillator distribution in future satellite payloads together with the optical inter-satellite link.

  3. Experiments in data collection technology using satellites

    NASA Technical Reports Server (NTRS)

    Anderson, R. E.; Lewis, J. R.; Trudell, B. J.

    1977-01-01

    A variety of techniques potentially useful to data collection have been tested. An automatic data collection platform with a minicomputer collects and preprocesses data, then sends desired information when interrogated through a communication satellite. Position surveillance by tone-code ranging through communication satellites is automatic, real time and accurate. Emergency medical data transmissions from ambulances to hospitals can be extended to rural and remote areas by direct satellite links. A small platform can send emergency-related data through a satellite while the satellite is routinely relaying powerful communication signals. A low orbit satellite provides means to locate existing emergency locator beacons.

  4. Searching for satellites of Ceres

    NASA Astrophysics Data System (ADS)

    Schmidt, B.; Li, J.; McFadden, L.; Mutchler, M.; McLean, B.; Russell, C.

    2014-07-01

    The existence of satellites, or lack thereof, around Ceres is of great interest to the Dawn mission, which is currently en route to Ceres and will arrive in February 2015. The Dawn spacecraft will orbit Ceres at altitudes of 1180 to 6400 km, well within the satellite stability region. The final opportunity for observations of Ceres with HST prior to Dawn's arrival occurred in April 2014, when Ceres will make a close pass at opposition to Earth. In addition to providing additional targets for exciting physical studies by the Dawn instruments, satellites, if there were any, would substantially affect Dawn's orbit planning in order to accommodate observations and ensure spacecraft safety. For example, detection of satellites would allow this program to derive a more accurate measurement of the mass of Ceres, which is important for the mission planners to determine the orbit of the spacecraft. With the observation planning process already underway, early detection of satellites will provide sufficient time to adapt mission plans to be able to observe any satellites on ingress or during the mapping orbits. The timing is particularly important, since the spacecraft now has use of only two reaction wheels, which is already impacting mission design, and which prevents Dawn from conducting its own deep satellite search as was accomplished prior to arrival at Vesta. Because of this, an HST survey is critical for Dawn operations at Ceres. Since satellite detection could require a change to the mission's nominal orbital strategy and present risk from dust associated with any satellites, it is crucial to put Dawn in the best position to succeed. HST observed Ceres using the High Resolution Channel (HRC) of the Advanced Camera for Surveys (ACS) to study the physical properties of Ceres and carried out surface mapping (Parker et al. 2004, Thomas et al. 2005, Li et al. 2006). Several ''long-V'' (F555W filter) exposures were taken using the full field of view of the ACS-HRC to

  5. Satellite voice broadcast system study, volume 2

    NASA Technical Reports Server (NTRS)

    Horstein, M.

    1985-01-01

    This study investigates the feasibility of providing Voice of America (VOA) broadcasts by satellite relay, rather than via terrestrial relay stations. Satellite voice broadcast systems are described for three different frequency bands: HF (26 MHz), VHF (68 MHz), and L-band (1.5 GHz). The geographical areas of interest at HF and L-band include all major land masses worldwide with the exception of the U.S., Canada, and Australia. Geostationary satellite configurations are considered for both frequency bands. In addition, a system of subsynchronous, circular satellites with an orbit period of 8 hours is developed for the HF band. VHF broadcasts, which are confined to the Soviet Union, are provied by a system of Molniya satellites. Satellites intended for HF or VHF broadcastinbg are extremely large and heavy. Satellite designs presented here are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. Even so, at HF it would take 47 geostationary satellites or 20 satellites in 8-hour orbits to fully satisfy the voice-channel requirements of the broadcast schedule provided by VOA. On the other hand, three Molniya satellites suffice for the geographically restricted schedule at VHF. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. Moreover, these satellites are comparable in size and weight to current satellites designed for direct broadcast of video program material.

  6. Mobile satellite regulation in the United States

    NASA Technical Reports Server (NTRS)

    Levin, Lon C.; Sonnenfeldt, Walter H.

    1990-01-01

    During the last decade, the U.S. FCC has developed the regulatory structure for the provision of mobile services via satellite. In May 1989, the FCC awarded American Mobile Satellite Corporation (AMSC) a license to provide the full range of domestic mobile satellite services in the U.S. At that time, the FCC reaffirmed the U.S. mobile satellite industry structure and spectrum allocations that had been adopted previously. Also in May 1989, the FCC authorized the Communications Satellite Corporation (COMSAT), the U.S. Signatory to Inmarsat, to provide international aeronautical satellite service via the Inmarsat system. Earlier in 1989, the FCC permitted the use of Ku-band satellites to provide messaging and tracking services. In the mid-1980's, the FCC established the Radiodetermination Satellite Service and awarded licenses. Among the mobile satellite matters currently facing the FCC are whether additional spectrum should be allocated for domestic 'generic' mobile satellite services, the regulatory structure for the provision of mobile satellite service on an interim basis before AMSC launches its dedicated satellites, and whether to authorize a low earth orbit satellite system to provide mobile data service.

  7. Orbit determination accuracies using satellite-to-satellite tracking. [applicable to the Tracking and Data Relay Satellite system

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.; Argentiero, P. D.; Schmid, P. E.

    1978-01-01

    The results of the ATS-6/GEOS-3 and the ATS-6/NIMBUS-6 satellite-to-satellite tracking orbit determination experiments are reported. The tracking systems used in these experiments differ from the Tracking and Data Relay Satellite System (TDRSS), primarily in the use of one rather than two synchronous relay satellites. However, the simulations mentioned indicate that the insights gained from the experiments with regard to proper data reduction techniques and expected results are applicable to the TDRSS.

  8. Satellite height determination using satellite-to-satellite tracking and ground laser systems

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.

    1972-01-01

    An attempt was made to use GEOS-C spacecraft height, as measured by the onboard radar altimeter, for an improved determination of the earth's gravitational field and for the determination of the variation of the physical surface of the oceans. Two tracking system approaches to accurately determine the spacecraft height (orbit) are described and their results stated. These are satellite-to-satellite tracking (SST) and ground-laser tracking (GLT). Height variations can be observed in the dm-regions using SST and in the m-region using present GLT.

  9. Satellite height determination using satellite-to-satellite tracking and ground laser systems

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.

    1972-01-01

    The height of the GEOS-C spacecraft was utilized as measured by the onboard radar altimeter, for an improved determination of the earth's gravitational field and for the determination of the variation of the physical surface of the oceans. Two tracking system approaches to accurately determine the spacecraft height (orbit) are described and their results stated. These are satellite-to-satellite tracking (SST) and ground laser tracking (GLT). Height variations can be observed in the dm-regions using SST and in the m-region using present GLT.

  10. Electric power for space satellites

    NASA Technical Reports Server (NTRS)

    Mackenzie, C. M.

    1974-01-01

    The development of electric power systems for satellites is discussed as an evolutionary process requiring the integration of power generation, power storage, and power control and distribution. The growth of space electric power systems is traced. The capabilities and limitations of the various elements (i.e. silicon solar cells) are discussed together with their impact on future technological growth.

  11. Small satellites for tropical applications

    NASA Astrophysics Data System (ADS)

    Montpetit, Marie-Jose; Bonn, Ferdinand

    1993-11-01

    A number of mission studies were performed to assess the suitability of small satellite systems for tropical data acquisition. These studies took into account the specifics of the tropical user communities and were focused on remote sensing and resource management issues. The requirements and potential solutions for four application areas are discussed. For monitoring of forest and agricultural vegetation, a small synthetic aperture radar is considered with P, C, or X band imaging, possibly supplemented by a high resolution multispectral imager. The radar would have the capability to monitor below cloud cover which is often found in tropical regions. Optical, microwave, or spectrographic imaging would also be useful in small satellites for disaster monitoring (notably of floods), land management, and air pollution monitoring. A small satellite with data storage and forwarding capability is also envisioned to collect data from dependable, low-power, and low-cost ground sensors via a simple ultrahigh frequency uplink and download the data on a very high frequency downlink. All the small satellites would be launched in low inclination orbits to ensure a number of consecutive passes over the targeted tropical area.

  12. The DSI small satellite launcher

    NASA Technical Reports Server (NTRS)

    Nichols, S.; Gibbons, D.; Wise, J.; Nguyen, D.

    1992-01-01

    A new launcher has been developed by DSI, that is compatible with the GAS canisters. It has the proven capability to deploy a satellite from an orbiting Shuttle that is 18 inches in diameter, 31 inches long, and weighing 190 pounds. These DSI Launchers were used aboard the Discovery (STS-39) in May 1991 as part of the Infrared Background Signature Survey (IBSS) to deploy three small satellites known as Chemical Release Observation (CRO) satellites A, B, and C. Because the satellites contained hazardous liquids (MMH, UDMH, and MON-10) and were launched from GAS Cylinders without motorized doors, the launchers were required to pass NASA Shuttle Payload safety and verification requirements. Some of the more interesting components of the design were the V-band retention and separation mechanism, the separation springs, and the launcher electronics which provided a properly inhibited release sequence operated through the Small Payload Accommodations Switch Panel (SPASP) on board the Orbiter. The original plan for this launcher was to use a motorized door. The launcher electronics, therefore has the capability to be modified to accommodate the door, if desired.

  13. Geosynchronous Meteorological Satellite Data Seminar

    NASA Technical Reports Server (NTRS)

    1976-01-01

    A seminar was organized by NASA to acquaint the meteorological community with data now available, and data scheduled to be available in the future, from geosynchronous meteorological satellites. The twenty-four papers were presented in three half-day sessions in addition to tours of the Image Display and LANDSAT Processing Facilities during the afternoon of the second day.

  14. Adaptive arrays for satellite communications

    NASA Technical Reports Server (NTRS)

    Gupta, I. J.; Ksienski, A. A.

    1984-01-01

    The suppression of interfering signals in a satellite communication system was studied. Adaptive arrays are used to suppress interference at the reception site. It is required that the interference be suppressed to very low levels and a modified adaptive circuit is used which accomplishes the desired objective. Techniques for the modification of the transmit patterns to minimize interference with neighboring communication links are explored.

  15. Medium Spatial Resolution Satellite Characterization

    NASA Technical Reports Server (NTRS)

    Stensaas, Greg

    2007-01-01

    This project provides characterization and calibration of aerial and satellite systems in support of quality acquisition and understanding of remote sensing data, and verifies and validates the associated data products with respect to ground and and atmospheric truth so that accurate value-added science can be performed. The project also provides assessment of new remote sensing technologies.

  16. Video Teleconferencing: Learning via Satellite.

    ERIC Educational Resources Information Center

    Rusk, Mike

    1988-01-01

    Discusses the use of one-way video, two-way audio teleconferencing as a teaching medium. Describes the teleconference facilities of Tulsa Junior College, the College Satellite Network and National University Teleconference Network, and the roles played by various people and groups in teleconferencing. Considers the cognitive aspects of video…

  17. University Satellite Campus Management Models

    ERIC Educational Resources Information Center

    Fraser, Doug; Stott, Ken

    2015-01-01

    Among the 60 or so university satellite campuses in Australia are many that are probably failing to meet the high expectations of their universities and the communities they were designed to serve. While in some cases this may be due to the demand driven system, it may also be attributable in part to the ways in which they are managed. The…

  18. Introductory Course on Satellite Navigation

    ERIC Educational Resources Information Center

    Giger, Kaspar; Knogl, J. Sebastian

    2012-01-01

    Satellite navigation is widely used for personal navigation and more and more in precise and safety-critical applications. Thus, the subject is suited for attracting the interest of young people in science and engineering. The practical applications allow catching the students' attention for the theoretical background. Educational material on the…

  19. The Mobile Satellite Services Market.

    ERIC Educational Resources Information Center

    Anderson, Samuel

    Mobile satellite (MSAT) technology is the basis for a new component of the telecommunications industry capable of providing services to small inexpensive subscriber terminals located almost any place in the world. The market for MSAT space segment capacity (bandwidth and power) is a natural monopoly that can be logically and technically…

  20. Satellites of Mars - Geologic history

    NASA Technical Reports Server (NTRS)

    Thomas, P.; Veverka, J.; Bell, J.; Lunine, J.; Cruikshank, D.

    1992-01-01

    The small, irregularly shaped satellites of Mars, Phobos and Deimos, provide the most detailed view of the geomorphic forms and processes important on small solar system bodies. The satellites appear to be very similar in composition, strongly resembling carbonaceous asteroids; however, recent groundbased spectra suggest that their surfaces have little bound or interlayer water. Despite their similar compositions, sizes and environments, Phobos and Deimos have radically different surface features. Phobos is densely covered by craters that are nearly lunar in appearance; Deimos' craters are subdued and largely filled in by debris. Phobos shows only local downslope movement of regolith; Deimos has it on a global scale. Phobos is criss-crossed by linear depressions; Deimos has none. Crater ejecta appear to be retained near their sources on Phobos while the ejecta are widespread on Deimos. The reasons for the differences between the satellites are not known; imaging of asteroids should tell us which, if either, satellite is typical of the many small bodies that populate the asteroid belt.

  1. Satellite Sees 3 Tropical Cyclones

    NASA Video Gallery

    This animation of GOES-15 satellite observations from July 8 (6:00 p.m. EDT) to July 12 (9:30 a.m. EDT), 2012, shows Hurricane Daniel weaken to a remnant low pressure area nearing Hawaii, while Emi...

  2. Technology for satellite power conversion

    NASA Technical Reports Server (NTRS)

    Campbell, D. P.; Gouker, M. A.; Summers, C.; Gallagher, J. J.

    1984-01-01

    Techniques for satellite electromagnetic energy transfer and power conversion at millimeter and infrared wavelengths are discussed. The design requirements for rectenna receiving elements are reviewed for both coherent radiation sources and Earth thermal infrared emission. Potential power transmitters including gyrotrons, free electron lasers, and CO2 lasers are assessed along with the rectification properties of metal-oxide metal diode power converters.

  3. Satellite services and orbital retrieval

    NASA Technical Reports Server (NTRS)

    Adornato, R. J.

    1985-01-01

    Within the capabilities of the Space Shuttle Orbiter, a broad range of services which can be made available to the satellite user community as summarized. Payload deployment, close proximity retrieval, and a number of other mission related functions are discussed. The focus here is on close proximity retrieval and retrieval of payloads in higher energy low Earth orbits.

  4. Satellite monitoring of black bear.

    NASA Technical Reports Server (NTRS)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  5. Artificial-Satellite-Analysis Program

    NASA Technical Reports Server (NTRS)

    Kwok, Johnny H.

    1989-01-01

    Artificial Satellite Analysis Program (ASAP) is general orbit-predicting computer program incorporating sufficient orbit-modeling accuracy for design and planning of missions and analysis of maneuvers. Suitable for study of planetary-orbit missions with spacecraft trajectories of reconnaissance (flyby) and exploratory (mapping) nature. Not written for specific mission and intended use for almost any planetary orbiting mission. Written in FORTRAN 77.

  6. A power satellite sonic simulator

    NASA Technical Reports Server (NTRS)

    Ott, J. H.; Rice, J. S.

    1980-01-01

    A simulator is described which generates and transmits a beam of audible sound energy mathematically similar to the solar power satellite (SPS) power beam. The simulator provides a laboratory means for analysis of ground based closed loop SPS phase control and of ionospheric effects on the SPS microwave power beam.

  7. Satellite Communications: Hopes and Fears

    ERIC Educational Resources Information Center

    Sirkin, Abraham M.

    1978-01-01

    The potentials of space communication, including the prospects and problems of direct broadcast TV satellites, are examined. Considered are future visions, internal and international goals, economic factors, political constraints, prior consent, U.S. and U.N. positions, and free flow of information. (LBH)

  8. Skynet satellite electron precharging experiments

    NASA Technical Reports Server (NTRS)

    Vanlint, V. A. J.; Fromme, D. A.; Stettner, R.

    1979-01-01

    Large surface areas (approximately 1 sq m) of the Skynet I qualification model satellite were exposed to the environments of a flux of monoenergetic electrons and pulsed high-intensity X-ray photons from an exploding-wire-radiator source, separately and simultaneously. Experiments were performed with both the cylindrical solar cell panels and the end thermal blanket exposed to these environments. The satellite was instrumented with fiber-optics isolated fast-response sensors capable of sensing and recording the time-varying electric fields and surface currents on the satellite. Spontaneous discharges of the two surfaces were characterized prior to measurements of the interaction of the system-generated electromagnetic pulse from the X-ray photon burst with the electron precharged surfaces. A two-dimensional self-consistent finite difference computer code was used to predict the currents on the Skynet both with and without precharging of the thermal-blanket. These calculations, which used an thermal-blanket voltage profile, predicted a factor of 2 increase in satellite exterior axial currents.

  9. Water Quality Monitoring by Satellite

    ERIC Educational Resources Information Center

    Journal of Chemical Education, 2004

    2004-01-01

    The availability of abundant water resources in the Upper Midwest of the United States is nullified by their contamination through heavy commercial and industrial activities. Scientists have taken the responsibility of detecting the water quality of these resources through remote-sensing satellites to develop a wide-ranging water purification plan…

  10. Electric propulsion for small satellites

    NASA Astrophysics Data System (ADS)

    Keidar, Michael; Zhuang, Taisen; Shashurin, Alexey; Teel, George; Chiu, Dereck; Lukas, Joseph; Haque, Samudra; Brieda, Lubos

    2015-01-01

    Propulsion is required for satellite motion in outer space. The displacement of a satellite in space, orbit transfer and its attitude control are the task of space propulsion, which is carried out by rocket engines. Electric propulsion uses electric energy to energize or accelerate the propellant. The electric propulsion, which uses electrical energy to accelerate propellant in the form of plasma, is known as plasma propulsion. Plasma propulsion utilizes the electric energy to first, ionize the propellant and then, deliver energy to the resulting plasma leading to plasma acceleration. Many types of plasma thrusters have been developed over last 50 years. The variety of these devices can be divided into three main categories dependent on the mechanism of acceleration: (i) electrothermal, (ii) electrostatic and (iii) electromagnetic. Recent trends in space exploration associate with the paradigm shift towards small and efficient satellites, or micro- and nano-satellites. A particular example of microthruster considered in this paper is the micro-cathode arc thruster (µCAT). The µCAT is based on vacuum arc discharge. Thrust is produced when the arc discharge erodes some of the cathode at high velocity and is accelerated out the nozzle by a Lorentz force. The thrust amount is controlled by varying the frequency of pulses with demonstrated range to date of 1-50 Hz producing thrust ranging from 1 µN to 0.05 mN.

  11. GOES-R: Satellite Insight

    NASA Technical Reports Server (NTRS)

    Fitzpatrick, Austin J.; Leon, Nancy J.; Novati, Alexander; Lincoln, Laura K.; Fisher, Diane K.

    2012-01-01

    GOES-R: Satellite Insight seeks to bring awareness of the GOES-R (Geostationary Operational Environmental Satellite -- R Series) satellite currently in development to an audience of all ages on the emerging medium of mobile games. The iPhone app (Satellite Insight) was created for the GOES-R Program. The app describes in simple terms the types of data products that can be produced from GOES-R measurements. The game is easy to learn, yet challenging for all audiences. It includes educational content and a path to further information about GOESR, its technology, and the benefits of the data it collects. The game features action-puzzle game play in which the player must prevent an overflow of data by matching falling blocks that represent different types of GOES-R data. The game adds more different types of data blocks over time, as long as the player can prevent a data overflow condition. Points are awarded for matches, and players can compete with themselves to beat their highest score.

  12. Cryovolcanism on the icy satellites

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.

    1994-01-01

    Evidence of past cryovolcanism is widespread and extremely varied on the icy satellites. Some cryovolcanic landscapes, notably on Triton, are similar to many silicate volcanic terrains, including what appear to be volcanic rifts, calderas and solidified lava lakes, flow fields, breached cinder cones or stratovolcanoes, viscous lava domes, and sinuous rilles. Most other satellites have terrains that are different in the important respect that no obvious volcanoes are present. The preserved record of cryovolcanism generally is believed to have formed by eruptions of aqueous solutions and slurries. Even Triton's volcanic crust, which is covered by nitrogen-rich frost, is probably dominated by water ice. Nonpolar and weakly polar molecular liquids (mainly N2, CH4, CO, CO2, and Ar), may originate by decomposition of gas-clathrate hydrates and may have been erupted on some icy satellites, but without water these substances do not form rigid solids that are stable against sublimation or melting over geologic time. Triton's plumes, active at the time of Voyager 2's flyby, may consist of multicomponent nonpolar gas mixtures. The plumes may be volcanogenic fumaroles or geyserlike emissions powered by deep internal heating, and, thus, the plumes may be indicating an interior that is still cryomagmatically active; or Triton's plumes may be powered by solar heating of translucent ices very near the surface. The Uranian and Neptunian satellites Miranda, Ariel, and Triton have flow deposits that are hundreds to thousands of meters thick (implying highly viscous lavas); by contrast, the Jovian and Saturnian satellites generally have plains-forming deposits composed of relatively thin flows whose thicknesses have not been resolved in Voyager images (thus implying relatively low-viscosity lavas). One possible explanation for this inferred rheological distinction involves a difference in volatile composition of the Uranian and Neptunian satellites on one hand and of the Jovian and

  13. Cryovolcanism on the icy satellites

    USGS Publications Warehouse

    Kargel, J.S.

    1994-01-01

    Evidence of past cryovolcanism is widespread and extremely varied on the icy satellites. Some cryovolcanic landscapes, notably on Triton, are similar to many silicate volcanic terrains, including what appear to be volcanic rifts, calderas and solidified lava lakes, flow fields, breached cinder cones or stratovolcanoes, viscous lava domes, and sinuous rilles. Most other satellites have terrains that are different in the important respect that no obvious volcanoes are present. The preserved record of cryovolcanism generally is believed to have formed by eruptions of aqueous solutions and slurries. Even Triton's volcanic crust, which is covered by nitrogen-rich frost, is probably dominated by water ice. Nonpolar and weakly polar molecular liquids (mainly N2, CH4, CO, CO2, and Ar), may originate by decomposition of gas-clathrate hydrates and may have been erupted on some icy satellites, but without water these substances do not form rigid solids that are stable against sublimation or melting over geologic time. Triton's plumes, active at the time of Voyager 2's flyby, may consist of multicomponent nonpolar gas mixtures. The plumes may be volcanogenic fumaroles or geyserlike emissions powered by deep internal heating, and, thus, the plumes may be indicating an interior that is still cryomagmatically active; or Triton's plumes may be powered by solar heating of translucent ices very near the surface. The Uranian and Neptunian satellites Miranda, Ariel, and Triton have flow deposits that are hundreds to thousands of meters thick (implying highly viscous lavas); by contrast, the Jovian and Saturnian satellites generally have plains-forming deposits composed of relatively thin flows whose thicknesses have not been resolved in Voyager images (thus implying relatively low-viscosity lavas). One possible explanation for this inferred rheological distinction involves a difference in volatile composition of the Uranian and Neptunian satellites on one hand and of the Jovian and

  14. CCRS Landcover Maps From Satellite Data

    SciTech Connect

    Trishchenko, Alexander

    2008-01-15

    The Canadian Centre for Remote Sensing (CCRS) presents several landcover maps over the SGP CART site area (32-40N, 92-102W) derived from satellite data including AVHRR, MODIS, SPOT vegetation data, and Landsat satellite TM imagery.

  15. Cloudsat and MTSAT Satellites Observer Atsani

    NASA Video Gallery

    This Aug. 19 image combines cloud imagery from Japan's MTSAT satellite and NASA's CloudSat satellite. Areas of pink and red designate larger amounts of liquid and ice. Light blue indicate smaller c...

  16. TRMM Satellite Shows Heavy Rainfall in Cristina

    NASA Video Gallery

    NASA's TRMM satellite rainfall data was overlaid on an enhanced visible/infrared image from NOAA's GOES-East satellite showing cloud and rainfall extent. Green areas indicate rainfall at over 20 mm...

  17. TRMM Satellite Rainfall Data on Iselle

    NASA Video Gallery

    TRMM satellite rainfall data overlaid on an enhanced infrared image from NOAA's GOES-West satellite shows heavy rainfall occurring around the Iselle's eye. The most intense rain was falling at a ra...

  18. 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 ...

  19. Our World: A-Train Satellites

    NASA Video Gallery

    The A-Train consists of five satellites orbiting Earth that use the latest NASA technology to study the Earth's system. This segment introduces Aqua, one of the satellites that studies water on Earth.

  20. IMPROVING BIOGENIC EMISSION ESTIMATES WITH SATELLITE IMAGERY

    EPA Science Inventory

    This presentation will review how existing and future applications of satellite imagery can improve the accuracy of biogenic emission estimates. Existing applications of satellite imagery to biogenic emission estimates have focused on characterizing land cover. Vegetation dat...

  1. First Public Library Satellite Receiver System.

    ERIC Educational Resources Information Center

    Donaldson, Marion F.

    1982-01-01

    Description of video services at Lake County Public Library, Indiana, highlights the installation of a satellite receiver system and notes funding and justification, components of a satellite system, decisions and sources of assistance, programming available, and future considerations. (EJS)

  2. NASA compendium of satellite communications programs

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A comprehensive review of worldwide satellite communication programs is reported that ranges in time from the inception of satellite communications to mid-1971. Particular emphasis is placed on program results, including experiments conducted, communications system operational performance, and technology employed.

  3. Meteorological satellites: Past, present, and future

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Past developments, accomplishments and future potential of meteorological satellites are discussed. Meteorological satellite design is described in detail. Space platforms and their meteorological applications are discussed. User needs are also discussed.

  4. GOES Weather Satellite Watches The Sun

    NASA Video Gallery

    NASA satellites such as STEREO, SOHO, and SDO are dedicated to studying the sun. GOES is a weather satellite but also watches the sun constantly. Watch this video and learn why space weather data i...

  5. Program and technology on timeservice via satellite.

    NASA Astrophysics Data System (ADS)

    Liang, Shuangyou

    1995-06-01

    According to the status of broadcasting-television via synchronous satellites in China, the technology and control methods to realize the timeservice with high precision via synchronous satellites are presented in this paper. In this program, the time signal in the CCTV signals is retained and the satellite orbital parameters and some other parameters are inserted into the CCTV signals without using additional satellite channels.

  6. Teledesic pushes $9-billion, 900-satellite system

    NASA Astrophysics Data System (ADS)

    1994-03-01

    Teledesic Corp. is seeking FCC approval to deploy a communication satellite system, costing $9 billion and using more than 900 satellites in low Earth orbit. This system would provide telephone and broadband data service to remote areas and developing countries. The two major stockholders in Teledesic are William Gates (of Microsoft Corp.) and Craig McCaw (of McCaw Cellular Communications). Each satellite would act as a node in a packet-switching network. The satellites would provide continuous global coverage.

  7. 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.

  8. Compendium of Applications Technology Satellite user experiments

    NASA Technical Reports Server (NTRS)

    Engler, N. A.; Strange, J. D.; Hein, G. F.

    1976-01-01

    The achievements of the user experiments performed with ATS satellites from 1967 to 1973 are summarized. Included are fixed and mobile point to point communications experiments involving voice, teletype and facsimile transmissions. Particular emphasis is given to the Alaska and Hawaii satellite communications experiments. The use of the ATS satellites for ranging and position fixing of ships and aircraft is also covered. The structure and operating characteristics of the various ATS satellite are briefly described.

  9. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Reilly, Charles H.; Walton, Eric K.; Kohnhorst, Paul

    1987-01-01

    A procedure is described that was used to calculate minimum required satellite separations based on total link carrier to interference requirements. Also summarized are recent results with a switching algorithm for satellite synthesis problems. Analytic solution value bounds for two of the satellite synthesis models studied are described. Preliminary results from an empirical study of alternate mixed integer programming models for satellite synthesis are presented. Research plans for the near future are discussed.

  10. Laser beamed power: Satellite demonstration applications

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Westerlund, Larry H.

    1992-01-01

    It is possible to use a ground-based laser to beam light to the solar arrays of orbiting satellites, to a level sufficient to provide all or some of the operating power required. Near-term applications of this technology for providing supplemental power to existing satellites are discussed. Two missions with significant commercial pay-off are supplementing solar power for radiation-degraded arrays and providing satellite power during eclipse for satellites with failed batteries.

  11. Earth resources satellite systems for flood monitoring

    NASA Technical Reports Server (NTRS)

    Mcginnis, D. F.; Rango, A.

    1975-01-01

    The environmental satellites NOAA-2 and ERTS-1 observed flooding in United States' rivers such as the Mississippi during 1973. Combination of NOAA-2 observation frequency and the ERTS-1 resolution provides an adequate satellite system for monitoring floods. Several polar-orbiting satellites of the ERTS type could view flooded areas at a reasonably high resolution every three to five days. A high-resolution earth-synchronous satellite would further enhance flood mapping by providing observations whenever clouds are absent.

  12. Developing a global aeronautical satellite system

    NASA Technical Reports Server (NTRS)

    Dement, Donald K.

    1988-01-01

    Arinc, an airline industry-owned and operated company in the United States, has taken steps toward establishing a global aeronautical satellite communications system. Plans call for initiation of a thin-route data operation in 1989, upgrading to establish voice communications via shared spot-beam transponders carried on other satellites, and deploying a worldwide network using dedicated satellites by 1994.

  13. Satellite Television and (Distance) Education in Australia.

    ERIC Educational Resources Information Center

    Millar, Alex C.

    The Australian national communications satellite AUSSAT, launched in August 1985, is used by government, business, and education. At this stage, the most comprehensive educational project using the satellite involves the state of Queensland, where the government has leased one of the satellite's transponders to provide services throughout the…

  14. Processor Units Reduce Satellite Construction Costs

    NASA Technical Reports Server (NTRS)

    2014-01-01

    As part of the effort to build the Fast Affordable Science and Technology Satellite (FASTSAT), Marshall Space Flight Center developed a low-cost telemetry unit which is used to facilitate communication between a satellite and its receiving station. Huntsville, Alabama-based Orbital Telemetry Inc. has licensed the NASA technology and is offering to install the cost-cutting units on commercial satellites.

  15. Sustained Satellite Missions for Climate Data Records

    NASA Technical Reports Server (NTRS)

    Halpern, David

    2012-01-01

    Satellite CDRs possess the accuracy, longevity, and stability for sustained moni toring of critical variables to enhance understanding of the global integrated Earth system and predict future conditions. center dot Satellite CDRs are a critical element of a global climate observing system. center dot Satellite CDRs are a difficult challenge and require high - level managerial commitment, extensive intellectual capital, and adequate funding.

  16. Satellite Uplink vs. Videotape in Borrower Training.

    ERIC Educational Resources Information Center

    Hanson, Gregory D.; Parsons, Robert L.

    2000-01-01

    Pennsylvania extension educators used satellite downlinks to provide distance education. However, the use of satellite downlinks was associated with technical difficulties, rigid scheduling, and high costs. Satellite downlinks were replaced with videotaped instructor presentations, which date quickly. The Internet may provide a more flexible and…

  17. 14 CFR 141.91 - Satellite bases.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor...

  18. 14 CFR 141.91 - Satellite bases.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor...

  19. 14 CFR 141.91 - Satellite bases.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor...

  20. 14 CFR 141.91 - Satellite bases.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor...

  1. 14 CFR 141.91 - Satellite bases.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Satellite bases. 141.91 Section 141.91... OTHER CERTIFICATED AGENCIES PILOT SCHOOLS Operating Rules § 141.91 Satellite bases. The holder of a... assistant chief instructor is designated for each satellite base, and that assistant chief instructor...

  2. Experiment In Aeronautical-Mobile/Satellite Communication

    NASA Technical Reports Server (NTRS)

    Jedrey, Thomas C.; Lay, Norman E.; Dessouky, Khaled

    1992-01-01

    Report describes study of performance of digital mobile/satellite communication terminals of advanced design intended for use in ground stations and airplanes in aeronautical-mobile service. Study was collaboration of NASA, Federal Aviation Administration (FAA), Communications Satellite Corp. (COMSAT), and International Maritime Satellite System (INMARSAT).

  3. Satellite to measure equatorial ozone layer

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The Atmosphere Explorer E (Explorer 55) Satellite is described. The satellite will gather information on the earth's upper atmosphere, particularly regarding the condition of the protective ozone layer. The satellite will also provide information concerning the earth's heat balance, and heat flow characteristics, and energy conversion mechanisms.

  4. Direct-Broadcast Satellites and Cultural Integrity

    ERIC Educational Resources Information Center

    Pool, Ithiel de Sola

    1975-01-01

    Argues that progress in satellite communications depends upon the assurance that satellites are useful to people in all countries, and that a world television network and a worldwide packet data communication system would help achieve that goal, and asserts that direct-satellite television broadcasting does not represent, at present, an active…

  5. The Impact of Satellites on Cable Communications.

    ERIC Educational Resources Information Center

    Chayes, Abram

    Two recent developments in communications satellite technology may speed the coming of cable TV (CATV) networks. First, increases in satellite power are reducing the cost of ground stations. Second, a connection between one ground station, the satellite, and any other ground station is no longer necessarily fixed. Now one station can communicate…

  6. Interim Service ISDN Satellite (ISIS) network model for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.; Hager, E. Paul

    1991-01-01

    The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Network Model for Advanced Satellite Designs and Experiments describes a model suitable for discrete event simulations. A top-down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ISDN modeling abstractions are added to permit the determination and performance for the NASA Satellite Communications Research (SCAR) Program.

  7. The Olympus satellite and satellite direct broadcasting in Italy

    NASA Astrophysics Data System (ADS)

    Castelli, E.; Tirro, S.

    Plans for the development of DBS-TV technology in Italy are discussed from the perspective of the Italian electronics industry, with an emphasis on experimental broadcasts using the Olympus satellite channel assigned to Italy by ESA. Consideration is given to the operating characteristics of PAL, MAC-C, MAC-D2, extended-MAC, and MUSE color-TV systems and their compatibility with DBS; the planned availability of TV channels on Olympus-type and Italsat-type satellites; individual, community, and CATV reception of DBS signals; the projected growth of the DBS audience in Italy, the UK, and the FRG by 1999; and the potential Italian market for satellite receivers and antennas. The need for prompt completion and evaluation of the Olympus experiments and antennas. The need for prompt completion and evaluation of the Olympus experiments (beginning in 1987) and selection of the systems to be implemented, so that the industry can supply the home equipment required on time, is stressed. Tables of numerical data and maps of the Olympus coverage areas are provided.

  8. Direct broadcast satellite service by direct broadcast satellite corporation

    NASA Astrophysics Data System (ADS)

    Pritchard, W. L.; Radin, H. W.

    1984-03-01

    It is noted that common carrier operation implies the offer to transmit television programs or any other information in electronic form for any customer at a rate posted in a tariff recorded at the FCC and applied without discrimination. The satellite system developed must be flexible enough to provide virtually any transmision service its customers may decide to offer at some future time. This means that spot beams must be available, which will permit the programmer to concentrate his offerings on particular regions of the country. Also, with the first satellite, there will be full-coverage service to the entire contiguous United States; in this way, programmers wishing to reach a nationwide audience will be able to do so from the beginning of their DBS operation. In addition, there will be an effective isotropic radiated power level that is high enough to accommodate high-definition television. As a common carrier, it is also necessary to seek the maximum possible standardization of signal transmission formats, receiver and antenna characteristics, and satellite locations so that programmers wishing to provide either subscription-supported or advertiser-supported programs can reach the widest possible audiences.

  9. 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

  10. A new wave of communication satellites

    NASA Technical Reports Server (NTRS)

    Lovell, R. R.; Cuccia, C. L.

    1984-01-01

    Satellites provide at present telephone, television, data, and business services on a national, regional, and international scale, and the geostationary arc has become crowded at C-band (6/4 GHz) and Ku-band (14/11 GHz) frequencies. The evolution and the present state of satellite communications are discussed along with details regarding the development of direct broadcast satellites, the position of Canada with respect to satellite communications, Japanese developments, ESA and Eutelsat, aspects of collaboration between France and Germany regarding communications satellites, the United Kingdom, and the Nordic countries.

  11. Inter-satellite laser link simulation analysis

    NASA Astrophysics Data System (ADS)

    Tong, Lanjuan; Guan, Hui; Wang, Zhilin

    2015-11-01

    The characteristic of satellite communication link was firstly described and four application modes were put forward. By comparison, it is suggested that microwave link is used in satellite-to-ground communication and laser link is used in inter-satellite communication. Secondly the condition and composition of laser link establishment was analyzed and laser link model was set up, and the principle and composition of APT system was described. Finally, based on STK and MATLAB platform, the process of inter-satellite laser link establishment was designed, and setting the scene of TDRS capturing and tracking user's satellite as an example, simulation was realized and demonstrated.

  12. Oceanic Satellite Data Distribution System

    NASA Technical Reports Server (NTRS)

    Montgomery, D. R.

    1980-01-01

    The Satellite Data Distribution System (SDDS) serves to process satellite-derived ocean observations, generate ocean analysis and forecast products, and distribute the products to a limited set of commercial users. The SDDS functions in series with the U.S. Navy Fleet Numerical Oceanography Center (FNOC) to provide products on a near-real-time basis to commercial marine industries. Conventional meteorological and oceanographic observations provided to FNOC serve as the input set to the numerical analysis and forecast models. Large main-frame computers are used to analyze and forecast products on a routine, operational basis (at 6-hour and 12-hour synoptic times). The products, reformatted to meet commercial users needs, are transferred to a NASA-owned computer for storage and distribution. Access to the information is possible either by a commercial dial-up packet-switching network or by a direct computer-computer connection.

  13. Ephemeris errors of GPS satellites

    NASA Technical Reports Server (NTRS)

    Colombo, O. L.

    1986-01-01

    Numerical models are developed to examine the potential effects of solar radiation, the terrestrial gravitational field, and the estimated initial state of the Global Positioning System (GPS) satellites, along with the capability of current models to account for the effects on the ephemeris of the GPS constellation. Of particular interest is the accuracy of the satellite position predictions for applications in geodesy. The main characteristics of the GPS orbits are reviewed and linear combinations of possible errors for 3 day ephemerides are examined. It is shown that the effects of the forces on the GPS orbits will be dynamic, yet can be expressed simply enough to maintain positioning accuracy to 1 percent. The calculations can also take into consideration solar wind pressure on the solar panels.

  14. Satellite Relaying of Geophysical Data

    NASA Technical Reports Server (NTRS)

    Allenby, R. J.

    1977-01-01

    Data Collection Platforms (DCPs) for transmitting surface data to an orbiting satellite for relaying to a central data distribution center are being used in a number of geophysical applications. "Off-the-shelf" DCP's, transmitting through Landsat or GOES satellites, are fully capable of relaying data from low-data-rate instruments, such as tiltmeters or tide gauges. In cooperation with the Lamont-Doherty Geological Observatory, Goddard has successfully installed DCP systems on a tide gauge and tiltmeter array on Anegada, British Virgin Islands. Because of the high-data-rate requirements, a practical relay system capable of handling seismic information is not yet available. Such a system could become the basis of an operational hazard prediction system for reducing losses due to major natural catastrophies such as earthquakes, volcanic eruptions, landslides or tsunamis.

  15. Aerial Photographs and Satellite Images

    USGS Publications Warehouse

    U.S. Geological Survey

    1997-01-01

    Photographs and other images of the Earth taken from the air and from space show a great deal about the planet's landforms, vegetation, and resources. Aerial and satellite images, known as remotely sensed images, permit accurate mapping of land cover and make landscape features understandable on regional, continental, and even global scales. Transient phenomena, such as seasonal vegetation vigor and contaminant discharges, can be studied by comparing images acquired at different times. The U.S. Geological Survey (USGS), which began using aerial photographs for mapping in the 1930's, archives photographs from its mapping projects and from those of some other Federal agencies. In addition, many images from such space programs as Landsat, begun in 1972, are held by the USGS. Most satellite scenes can be obtained only in digital form for use in computer-based image processing and geographic information systems, but in some cases are also available as photographic products.

  16. Electric propulsion for communications satellites

    NASA Technical Reports Server (NTRS)

    Free, B. A.; Guman, W. J.; Herron, B. G.; Zafran, S.

    1978-01-01

    Electric propulsion systems derive their low overall mass, relative to chemical propulsion systems, from an optimized mix of independently controlled power and mass flow rate. A significant reduction in mass can be secured by substituting electric propulsion for conventional hydrazine systems for all the major propulsion tasks of a communications satellite. Additional advantages for all electric propulsion maneuvers are precision location and higher pointing accuracy. Three auxiliary electric propulsion systems are now available for application on communications satellites: the electrically augmented hydrazine system, the Teflon pulsed plasma system, and the mercury ion thruster system. Primary electric propulsion will be available in the mid to late 1980s as a spin-off of NASA's program of interplanetary exploration.

  17. Bankfull Discharge Using Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Leão, J. O.; Silva, J. S.; Research Team Of Rhasa

    2013-05-01

    Satellite altimetry is now a mature tool to collect water levels over large and medium-size rivers. The present study is dedicated to the determination of bankfull discharge using satellite altimetry and imagery to determine hydrological parameters such as the phase of the bankfull discharge at the crossing of the river bed with the ground track of the altimetry missions or the surface slope of the river. We applied the methodology to the two major tributaries of the Amazon river, namely the Rio Madeira and the Rio Negro. The results are a significzant difference in the values of bankfull discharge in the two basins, together with significant difference in along-course slopes, reflecting the difference in geomorphological context between the two watersheds.

  18. Thermal Targets for Satellite Calibration

    SciTech Connect

    Villa-Aleman, E.

    2001-01-10

    The Savannah River Technology Center (SRTC) is currently calibrating the Multispectral Thermal Imager (MTI) satellite sponsored by the Department of Energy. The MTI imager is a research and development project with 15 wavebands in the visible, near-infrared, short-wave infrared, mid-wave infrared and long-wave infrared spectral regions. A plethora of targets with known temperatures such as power plant heated lakes, volcano lava vents, desert playas and aluminized Mylar tarps are being used in the validation of the five thermal bands of the MTI satellite. SRTC efforts in the production of ''cold targets'' with aluminized Mylar tarps will be described. Visible and thermal imagery and wavelength dependent radiance measurements of the calibration targets will be presented.

  19. Avionics for a Small Satellite

    NASA Technical Reports Server (NTRS)

    Abbott, Larry; Jochim, David; Schuler, Robert

    2001-01-01

    This paper discusses a small. seven and a half (7.5) inch diameter. satellite that NASA-JSC is developing as a technology demonstrator for an astronaut assistant free flyer. The Free Flyer is designed to off load flight crew work load by performing inspections of the exterior of Space Shuttle or International Space Station. The Free Flyer is designed to be operated by the flight crew thereby reducing the number of Extra Vehicle Activities (EVA) or by an astronaut on the ground further reducing crew work load. The paper focuses on the design constraint of a small satellite and the technology approach used to achieve the set of high performance requirements specified for the Free Flyer. Particular attention is paid to the processor card as it is the heart and system integration point of the Free Flyer.

  20. Polar orbiting operational weather satellites.

    NASA Technical Reports Server (NTRS)

    Stampfl, R. A.; Albert, G.

    1972-01-01

    The progress in the development of operational weather satellites is reviewed, covering their chronology from Explorer 7 of 1959 through Meteor 12 of June, 1972. Special attention is given to the development of the TIROS series satellites with the evolution of their operational sensors, data systems and performance requirements. The topics also include the data collection system designs, to Advanced Very High Resolution Radiometer (AVHRR), the sounder radiometer, the Solar Environment Monitor (SEM), the data processor, and TIROS-N operation and orbital characteristics. It is expected that TIROS-N and its forthcoming advanced versions will provide an effective technology for sensing environmental data on a global scale in the latter half of the decade.

  1. Mobile satellite systems - A review

    NASA Astrophysics Data System (ADS)

    McNally, J. L.; Breithaupt, R. W.

    1986-10-01

    A comprehensive set of technical, economic, and policy studies have been completed in Canada to determine the viability of a mobile service to satisfy Canada's requirements. This paper will present an overall review of these studies, give a rationale as to why narrowband technologies are necessary for the commercial viability of this service, and the approach taken in the development of these technologies. A brief review of activities and proposed mobile satellite systems in other areas besides North America is also given.

  2. Satellite services handbook. Interface guidelines

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Satellite interfaces for on orbit servicing, both manned and unmanned are identified, and is intended to be used by designers of space vehicles, both foreign and domestic. A primary concern is for design of interfaces with the astronaut in the loop, especially extravehicular activity, but also intravehicular activity and operations that are remote but have man-in-the-loop. The main emphasis is on servicing in low earth orbits from the Space Shuttle and also from the Space Station or other platforms.

  3. Satellite Observations in Science Education

    NASA Astrophysics Data System (ADS)

    Jasmin, T. J.; Whittaker, T. M.; Ackerman, S. A.; Howles, L. L.

    2005-12-01

    Satellite Observations in Science Education (SOSE) is a five year project funded by the NASA REASoN (Research, Education, Applications Solutions Network) mission. The goal is to develop an Internet-based education environment which provides interactive learning activities teaching remote sensing principles and exploratory data analysis. A toolkit of Reusable Content Objects will allow scientists and educators from many disciplines to easily assemble learning modules accessible from any Java-enabled web browser.

  4. Satellite services handbook. Interface guidelines

    NASA Astrophysics Data System (ADS)

    1983-12-01

    Satellite interfaces for on orbit servicing, both manned and unmanned are identified, and is intended to be used by designers of space vehicles, both foreign and domestic. A primary concern is for design of interfaces with the astronaut in the loop, especially extravehicular activity, but also intravehicular activity and operations that are remote but have man-in-the-loop. The main emphasis is on servicing in low earth orbits from the Space Shuttle and also from the Space Station or other platforms.

  5. The TOPEX satellite option study

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The applicability of an existing spacecraft bus and subsystems to the requirements of ocean circulation measurements are assessed. The operational meteorological satellite family TIROS and DMSP are recommended. These programs utilize a common bus to satisfy their Earth observation missions. Note that although the instrument complements were different, the pointing accuracies were different, and, initially, the boosters were different, a high degree of commonality was achieved.

  6. Cesium standard for satellite application

    NASA Technical Reports Server (NTRS)

    Bloch, M. B.; Meirs, M.; Pascaru, I.; Weinstein, B.

    1983-01-01

    A Cesium frequency standard that was developed for satellite applications is discussed. It weighs 23 lbs. and uses 23.5 watts of power, achieves a stability of 1 x ten to the minus 13th power/100,000 seconds, and is radiation hardened. To achieve the weight and reliability requirements, both thick and thin film hybrid circuits were utilized. A crystal oscillator is used to improve short-term stability and performance on a moving platform.

  7. The Swedish satellite project Viking

    SciTech Connect

    Hultqvist, B. )

    1990-05-01

    The Swedish satellite project Viking is described and related to earlier missions. Some new operational characteristics are discussed, including the real-time data analysis campaigns that were an important part of the project. Some areas of important scientific impact of the project are also described. Viking was specially designed and equipped for investigation of plasma physical acceleration and other processes in the transition region between hot and cold plasma on auroral latitude magnetic field lines.

  8. Desert Dust Satellite Retrieval Intercomparison

    NASA Technical Reports Server (NTRS)

    Carboni, E.; Thomas, G. E.; Sayer, A. M.; Siddans, R.; Poulsen, C. A.; Grainger, R. G.; Ahn, C.; Antoine, D.; Bevan, S.; Braak, R.; Brindley, H.; DeSouza-Mchado, S.; Deuze, J. L.; Diner, D.; Ducos, F.; Grey, W.; Hsu, C.; Kalashnikova, O. V.; Kahn, R.; North, P. R. J.; Salustro, C.; Smith, A.; Tanre, D.; Torres, O.; Veihelmann, B.

    2012-01-01

    This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim is to identify and understand the differences between current algorithms, and hence improve future retrieval algorithms. The satellite instruments considered are AATSR, AIRS, MERIS, MISR, MODIS, OMI, POLDER, and SEVIRI. An interesting aspect is that the different algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. These include multi-angle approaches (MISR, AATSR), polarisation measurements (POLDER), single-view approaches using solar wavelengths (OMI, MODIS), and the thermal infrared spectral region (SEVIRI, AIRS). Differences between instruments, together with the comparison of different retrieval algorithms applied to measurements from the same instrument, provide a unique insight into the performance and characteristics of the various techniques employed. As well as the intercomparison between different satellite products, the AODs have also been compared to co-located AERONET data. Despite the fact that the agreement between satellite and AERONET AODs is reasonably good for all of the datasets, there are significant differences between them when compared to each other, especially over land. These differences are partially due to differences in the algorithms, such as as20 sumptions about aerosol model and surface properties. However, in this comparison of spatially and temporally averaged data, at least as significant as these differences are sampling issues related to the actual footprint of each instrument on the heterogeneous aerosol field, cloud identification and the quality control flags of each dataset.

  9. Weather Satellite Pictures and How to Obtain Them.

    ERIC Educational Resources Information Center

    Petit, Noel J.; Johnson, Philip

    1982-01-01

    An introduction to satellite meteorology is presented to promote use of live weather satellite photographs in the classroom. Topics addressed include weather satellites, how they work, earth emissions, satellite photography, satellite image analysis, obtaining satellite pictures, and future considerations. Includes sources for materials to…

  10. Power beaming to communication satellites in GEO

    SciTech Connect

    Morgan, R.M.; Lipinski, R.J.

    1992-12-31

    Batteries normally provide power to geosynchronous satellites during earth eclipse 90 times each year, but the heavy charge-discharge cycle decreases their life expectancy. Battery life, and thus satellite life, could be extended by providing power during eclipses via laser illumination of the photovoltaic array. For a spin-stabilized satellite this would require 35 kill using an 8-m diameter transmission mirror (and 850-nm light) or 180 kW using a 3.5-m mirror. A 3-axis stabilized satellite has a larger span and requires an elongated spot to use a comparable laser. At present, 70 satellites are scheduled to be replaced by the year 2000 at a cost of almost $10 billion. Power beaming could save a substantial portion of this cost. Laser illumination also could augment solar power to increase the power available to new satellites. Increased power could boost the signal strength or allow more channels on the satellite. In addition, high-frequency channels (which require higher power to penetrate the atmosphere) could be used. Removal of waste heat from the satellite limits the amount of power that can be transmitted. Nevertheless, a spin-stabilized satellite with power beaming could generate 0.9 kill per square meter of the collector array, which is six times that of an equivalent conventional satellite using the same size solar panel. A 3-axis stabilized satellite could generate 0.6 kW/m{sup 2} (four times conventional).

  11. Antennas for mobile satellite communications

    NASA Technical Reports Server (NTRS)

    Huang, John

    1991-01-01

    A NASA sponsored program, called the Mobile Satellite (MSAT) system, has prompted the development of several innovative antennas at L-band frequencies. In the space segment of the MSAT system, an efficient, light weight, circularly polarized microstrip array that uses linearly polarized elements was developed as a multiple beam reflector feed system. In the ground segment, a low-cost, low-profile, and very efficient microstrip Yagi array was developed as a medium-gain mechanically steered vehicle antenna. Circularly shaped microstrip patches excited at higher-order modes were also developed as low-gain vehicle antennas. A more recent effort called for the development of a 20/30 GHz mobile terminal antenna for future-generation mobile satellite communications. To combat the high insertion loss encountered at 20/30 GHz, series-fed Monolithic Microwave Integrated Circuit (MMIC) microstrip array antennas are currently being developed. These MMIC arrays may lead to the development of several small but high-gain Ka-band antennas for the Personal Access Satellite Service planned for the 2000s.

  12. The Giant Planet Satellite Exospheres

    NASA Technical Reports Server (NTRS)

    McGrath, Melissa A.

    2014-01-01

    Exospheres are relatively common in the outer solar system among the moons of the gas giant planets. They span the range from very tenuous, surface-bounded exospheres (e.g., Rhea, Dione) to quite robust exospheres with exobase above the surface (e.g., lo, Triton), and include many intermediate cases (e.g., Europa, Ganymede, Enceladus). The exospheres of these moons exhibit an interesting variety of sources, from surface sputtering, to frost sublimation, to active plumes, and also well illustrate another common characteristic of the outer planet satellite exospheres, namely, that the primary species often exists both as a gas in atmosphere, and a condensate (frost or ice) on the surface. As described by Yelle et al. (1995) for Triton, "The interchange of matter between gas and solid phases on these bodies has profound effects on the physical state of the surface and the structure of the atmosphere." A brief overview of the exospheres of the outer planet satellites will be presented, including an inter-comparison of these satellites exospheres with each other, and with the exospheres of the Moon and Mercury.

  13. GOES satellite time code dissemination

    NASA Technical Reports Server (NTRS)

    Beehler, R. E.

    1983-01-01

    The GOES time code system, the performance achieved to date, and some potential improvements in the future are discussed. The disseminated time code is originated from a triply redundant set of atomic standards, time code generators and related equipment maintained by NBS at NOAA's Wallops Island, VA satellite control facility. It is relayed by two GOES satellites located at 75 W and 135 W longitude on a continuous basis to users within North and South America (with overlapping coverage) and well out into the Atlantic and Pacific ocean areas. Downlink frequencies are near 468 MHz. The signals from both satellites are monitored and controlled from the NBS labs at Boulder, CO with additional monitoring input from geographically separated receivers in Washington, D.C. and Hawaii. Performance experience with the received time codes for periods ranging from several years to one day is discussed. Results are also presented for simultaneous, common-view reception by co-located receivers and by receivers separated by several thousand kilometers.

  14. Binning of satellite magnetic anomalies

    NASA Technical Reports Server (NTRS)

    Goyal, H. K.; Vonfrese, R. R. B.; Hinze, W. J.

    1985-01-01

    Crustal magnetic anomaly signals over satellite orbits were simulated to investigate numerical averaging as an anomaly estimator. Averaging as an anomaly estimator involves significant problems concerning spatial and amplitude smoothing of the satellite magnetic observations. The results of simulations suggest that the error of numerical averaging constitutes a small and relatively minor component of the total error-budget of higher orbital anomaly estimates, whereas for lower orbital estimates numerical averaging error increases substantially. As an alternative to numerical averaging, least-squares collocation was investigated and observed to produce substantially more accurate anomaly estimates, particularly as the orbital elevation of prediction was decreased towards the crustal sources. In contrast to averaging, collocation is a significantly more resource-intensive procedure to apply because of the practical, but surmountable problems related to establishing and inverting the covariance matrix for accurate anomaly prediction. However, collocation may be much more effectively used to exploit the anomaly details contained in the lower orbital satellite magnetic data for geologic analysis.

  15. Payload accommodations. Satellite servicing support

    NASA Technical Reports Server (NTRS)

    Lee, Roscoe

    1990-01-01

    The proposed technology studies discussed at the Space Transportation Avionics Symposium in Williamsburg, VA on 7 to 9 November 1989, are discussed. The discussions and findings of the Payload Accommodations Subpanel are also summarized. The major objective of the proposed focused technology development is to develop and demonstrate (ground and flight) autonomous rendezvous, proximity operations, and docking/berthing capabilities to support satellite servicing. It is expected that autonomous rendezvous and docking (AR and D) capabilities will benefit both the users (e.g., satellite developers and operators) and the transportation system developers and operators. AR and D will provide increased availability of rendezvous and docking services by reducing the operational constraints associated with current capabilities. These constraints include specific lighting conditions, continuous space-to-ground communications, and lengthy ground tracking periods. AR and D will provide increased cost efficiency with the potential for reduced propellant expenditures and workloads (flight and/or ground crews). The AR and D operations will be more consistent, allowing more flexibility in the design of the satellite control system and docking/berthing mechanisms.

  16. Phillips Laboratory small satellite initiatives

    NASA Astrophysics Data System (ADS)

    Lutey, Mark K.; Imler, Thomas A.; Davis, Robert J.

    1993-09-01

    The Phillips Laboratory Space Experiments Directorate in conjunction with the Air Force Space Test Program (AF STP), Defense Advanced Research and Projects Agency (DARPA) and Strategic Defense Initiative Organization (SDIO), are managing five small satellite program initiatives: Lightweight Exo-Atmospheric Projectile (LEAP) sponsored by SDIO, Miniature Sensor Technology Integration (MSTI) sponsored by SDIO, Technology for Autonomous Operational Survivability (TAOS) sponsored by Phillips Laboratory, TechSat sponsored by SDIO, and the Advanced Technology Standard Satellite Bus (ATSSB) sponsored by DARPA. Each of these spacecraft fulfills a unique set of program requirements. These program requirements range from a short-lived `one-of-a-kind' mission to the robust multi- mission role. Because of these diverging requirements, each program is driven to use a different design philosophy. But regardless of their design, there is the underlying fact that small satellites do not always equate to small missions. These spacecraft with their use of or ability to insert new technologies provide more capabilities and services for their respective payloads which allows the expansion of their mission role. These varying program efforts culminate in an ATSSB spacecraft bus approach that will support moderate size payloads, up to 500 pounds, in a large set of orbits while satisfying the `cheaper, faster, better' method of doing business. This technical paper provides an overview of each of the five spacecraft, focusing on the objectives, payoffs, technologies demonstrated, and program status.

  17. Jupiter and Its Galilean Satellites

    NASA Technical Reports Server (NTRS)

    McGrath, Melissa A.

    2012-01-01

    Jupiter is one of the two most studied planets other than Earth in our Solar System. It is the largest, fastest rotating, has the strongest magnetic field, and an incredibly diverse set of satellites, most prominent of which are the four Galilean satellites discovered in 1610. Io, Europa, Ganymede and Callisto encompass some of the most bizarre environments known in the solar system, from Io, the most volcanically active and perhaps the most inhospitable body known, to Europa, currently thought to be the most likely extraterrestrial abode for habitability, to Ganymede, which is larger than Mercury, and Callisto, which has the oldest surface known in the solar system with the widest array of crater morphologies known. One of the premier areas of scientific return in solar system research in the past 15 years, due in large part to the Galileo mission and observations by the Hubble Space Telescope, has been a remarkable increase in our knowledge about these satellites. Discoveries have been made of tenuous molecular oxygen atmospheres on Europa and Ganymede, a magnetic field and accompanying auroral emissions at the poles of Ganymede, and of ozone and sulfur dioxide embedded in the surfaces of Europa, Ganymede and Callisto. Io's unusual sulfur dioxide atmosphere, including its volcanic plumes and strong electrodynamic interaction with magnetospheric plasma, has finally been quantitatively characterized. This talk will present highlights from the recent discoveries and advances in our understanding of these fascinating objects.

  18. Satellite Orbital Interpolation Comparison Methods

    NASA Astrophysics Data System (ADS)

    Richard, J.-Y.; Deleflie, F.; Gambis, D.

    2012-04-01

    A satellite or artificial probe orbit is made of time series of orbital elements such as state vectors (position and velocities, keplerian orbital elements) given at regular or irregular time intervals. These time series are fitted to observations, so that differences between observations (distance, radial velocity) and the theoretical quantity be minimal, according to a statistical criterion, mostly based on the least-squared algorithm. These computations are carried out using dedicated software, such as the GINS used by GRGS, mainly at CNES Toulouse and Paris Observatory. From an operational point of view, time series of orbital elements are 7-day long. Depending on the dynamical configurations, more generally, they can typically vary from a couple of days to some weeks. One of the fundamental parameters to be adjusted is the initial state vector. This can lead to time gaps, at the level of a few dozen of centimeters between the last point of a time series to the first one of the following data set. The objective of this presentation consists in the improvement of an interpolation method freed itself of such possible "discontinuities" resulting between satellite's orbit arcs when a new initial bulletin is adjusted. We show the principles of interpolation for these time series and compare solutions coming from different interpolation methods such as Lagrange polynomial, spline cubic, Chebyshev orthogonal polynomial and cubic Hermite polynomial. These polynomial coefficients are used to reconstruct and interpolate the satellite orbits without time gaps and discontinuities and requiring a weak memory size.

  19. Satellite remote sensing of vegetation

    NASA Astrophysics Data System (ADS)

    Mahr, Tobias; Peper, Eva; Schubert, Alexander; Warnach, Simon; Pöhler, Denis; Horbanski, Martin; Beirle, Steffen; Mies, Kornelia; Platt, Ulrich; Wagner, Thomas

    2013-04-01

    DOAS (Differential Optical Absorption Spectroscopy) allows to determine the concentration of trace gases based on their specific absorptions cross-sections along a light path. Since 1995, this principle is employed successfully on satellite-based instruments like GOME, GOME-2 and SCIAMACHY for the global measurement of stratospheric and tropospheric trace gases like ozone and nitrogen oxides. Usually, spectral signatures from the ground, where a big part of the sunlight is reflected, are neglected in the evaluation. This can lead to errors in the trace gas determination. However, these structures offer the opportunity to identify surface properties of the earth and different types of vegetation. To analyse spectral reflectance properties, high resolved reflection spectra (FWHM 0.29 nm) from 95 plants were measured between 350 and 1050 nm. They can serve as a basis for the analysis of satellite data. Including different vegetation reference spectra, it is possible to determine groups of plants with similar optical properties. This allows to derive global maps of the spatio-temporal variation of plant distribution by satellite remote sensing. We present first results of this technique based on SCIAMACHY observations.

  20. Communication satellite services for special purpose users

    NASA Technical Reports Server (NTRS)

    Wright, D. L.; Kiesling, J. D.

    1977-01-01

    The present study identifies potential satellite services, examines the technology necessary for efficient implementation of these services, and determines minimum service cost versus user network size. The generic satellite services evaluated comprise TV and radio distribution (for retransmission), video teleconferencing (interactive), audio/facsimile teleconferencing (interactive), multiplexed data/voice (point-to-point), and satellite-supported land mobile. Satellite costs are based on extrapolations from ongoing commercial satellite programs. Production methods, new technology, and effect of production quantities on present and future production costs are examined to provide information on earth station equipment cost versus the variable 'buy'. Six different launch vehicles from a Delta 2914 to a dedicated Shuttle and three frequency bands and both broadcast (no eclipse capability) and fixed service satellites are considered to assess the effect of satellite size on cost and performance. It is assumed that the user pays only for his prorata share of the space segment costs.

  1. Saturn's satellites: Predictions for Cassini

    NASA Astrophysics Data System (ADS)

    Delitsky, M. L.; Hibbitts, C. A.

    2004-11-01

    Saturn's satellites are subjected to a variety of energy inputs (from photons, magnetospheric and solar ions and electrons) which will affect their surface composition. The Saturn magnetosphere contains an assortment of ions, including O+ and H+ from sputtering of water ice on the inner satellites and N+ from sputtering of Titan's atmosphere. Implantation of these ions onto the surfaces of the satellites may produce compounds possibly detectable by Cassini instruments. The satellites contain water ice and carbon dioxide ice (and possibly organics, on Phoebe). In Delitsky and Lane (2002), chemistry resulting from nitrogen ion implantation into water ice and carbon dioxide ice was outlined. From deposition of N+ ions into H2O/CO2, a complicated C-H-N-O chemistry may result, including formation of isocyanates, nitriles, nitrogen oxides and amino acids. Upon irradiation, H2O/CO2 mixtures will yield esters, ketones, alcohols, carboxylic acids and other interesting compounds. Cassini's infrared instruments CIRS and VIMS have spectral ranges that can detect many bands of these compounds. VIMS spectral range is 0.35 - 5.1 microns; CIRS covers the spectral range 7 - 100 microns, although its Mid-IR interferometer portion (7 -16 microns) is where organic materials are particularly spectrally active. Weak features are present in the short IR for NO (1.91 microns), NO2 (1.95), NH3 (2.00, 2.24), CH3OH (2.27, 2.34), and CO2 (1.965, 2.01) [Quirico et al.,1999]. Some molecules have stronger absorption features at these wavelengths: [CO2: 4.25 - 4.27 microns; NH3: 3 microns and 9.2 microns (important because the 3 micron band can be masked by water); H2CO3: 3.88 microns (weak); HCOOH: 8.2 microns; O2: 9.7 microns]. These molecules may exist as ices, or as molecules trapped in the surface. CH- and CN-containing molecules absorb at 3.2 - 3.4 microns, and 4.6 microns, respectively. H2O2, detected on Europa by its 3.5 micron band, may exist in the icy surfaces of the Saturn satellites

  2. Downward continuation of gravity information from satellite to satellite tracking or satellite gradiometry in local areas

    NASA Technical Reports Server (NTRS)

    Rummel, R.

    1975-01-01

    Integral formulas in the parameter domain are used instead of a representation by spherical harmonics. The neglected regions will cause a truncation error. The application of the discrete form of the integral equations connecting the satellite observations with surface gravity anomalies is discussed in comparison with the least squares prediction method. One critical point of downward continuation is the proper choice of the boundary surface. Practical feasibilities are in conflict with theoretical considerations. The properties of different approaches for this question are analyzed.

  3. Satellite Operation Design for Assessing MTF Performance of Earth Observation Satellite Using Stellar Sources

    NASA Astrophysics Data System (ADS)

    Kim, Hee-Seob; Chung, Dae-Won; Choi, Hae-Jin

    2007-12-01

    Modulation Transfer Function (MTF) of satellite image is an important performance index in satellite image applications. Therefore MTF performance is assessed using satellite image for the ground target during LEOP phase after launch. But the MTF performance assessment using the ground target can be affected by imaging conditions such as cloud and weather. In this paper system requirements and satellite operation for assessing MTF performance of satellite image using stellar sources are proposed. Satellite capability in collecting stellar sources using the satellite which is designed for earth observation and satellite image usefulness for assessing MTF performances were analyzed. The proposed approach will be useful to assess MTF performance of earth observation satellite in lower earth orbit.

  4. Activities of Canadian Satellite Communications, Inc.

    NASA Astrophysics Data System (ADS)

    1992-12-01

    Canadian Satellite Communications (Cancom) has as its core business the provision of television and radio signals to cable systems in Canada, with the objective of making affordable broadcast signals available to remote and/or small communities. Cancom also provides direct-to-home services to backyard receiving dishes, as well as satellite digital data business communications services, satellite business television, and satellite network services. Its business communication services range from satellite links for big-city businesses with small branch operations located far from major centers, to a mobile messaging and tracking system for the trucking industry. Revenues in 1992 totalled $48,212,000 and net income was just over $7 million. Cancom bought 10 percent interest in Leosat Corp. of Washington, DC, who are seeking approval to operate a position locator network from low-orbit satellites. Cancom has also become a partner in SovCan Star Satellite Communications Inc., which will build an international satellite system in partnership with Russia. The first satellite in this east-west business network will be placed in a Russian orbital slot over the Atlantic by 1996, and a second satellite will follow for the Pacific region. This annual report of Cancom's activities for 1992 includes financial statements and a six year financial review.

  5. Global Positioning System Satellite Selection Method

    NASA Technical Reports Server (NTRS)

    Niles, Frederick A. (Inventor)

    2001-01-01

    The satellite selection method as utilized by the spaceborne Global Positioning System receiver provides navigational solutions and is designed for use in low Earth orbit. The satellite selection method is a robust algorithm that can be used a GPS receiver to select appropriate GPS satellites for use in calculating point solutions or attitude solutions. The method is takes into account the difficulty of finding a particular GPS satellite phase code, especially when the search range in greatly increased due to Doppler shifts introduced into the carrier frequency. The method starts with an update of the antenna pointing and spacecraft vectors to determine the antenna backplane direction. Next, the GPS satellites that will potentially be in view of the antenna are ranked on a list, whereby the list is generated based on the estimated attitude and position of each GPS satellite. Satellites blocked by the Earth are not entered on this list. A second list is created, whereby the GPS satellites are ranked according to their desirability for use in attitude determination. GPS satellites are ranked according to their orthogonality to the antenna backplane, and according to geometric dilution of precision considerations. After the lists are created, the channels of the spaceborne GPS receiver are assigned to various GPS satellites for acquisition and lock. Preliminary Doppler frequencies for searching are assigned to the various channels.

  6. German telecommunications satellite (Deutscher fernmelde satellit) (DFS-1 and -2)

    NASA Technical Reports Server (NTRS)

    Hiendlmeier, G.; Schmeller, H.

    1991-01-01

    The German Telecommunications Satellite (DFS) Program is to provide telecommunications service for high data rate transmission of text and video data to the Federal Republic of Germany within the 11-14 GHz and 20-30 GHz bands. The space segment of this program is composed of three satellites, DFS-1, DFS-2, and DFS-3, which will be located at 23.5 degrees E longitude of the geostationary orbit. The DFS will be launched from the Center Spatial Guyanis in French Giana on an Ariane launch vehicle. The mission follows the typical injection sequence: parking orbit, transfer orbit, and earth orbit. Attitude maneuvers will be performed to orient the spacecraft prior to Apogee Kick Motor (AKM) firing. After AKM firing, drift phase orbital and attitude maneuvers will be performed to place the spacecraft in its final geostationary position. The Deep Space Network (DSN) will support the transfer and drift orbit mission phases. Information is presented in tabular form for the following areas: DSN support, compatibility testing, frequency assignments, telemetry, command, and tracking support responsibilities.

  7. Mobile satellite systems. A review

    NASA Astrophysics Data System (ADS)

    McNally, J. L.; Breithaupt, R. W.

    The advantages of a mobile satellite system have been recognized worldwide, and after the 1979 World Administrative Radio Conference (WARC) identified spectrum in the 806 to 890 MHz band for region 2, the Canadian Government quickly took steps to provide mobile satellite services for all of Canada including the 200 mile offshore ocean territorial limits. A comprehensive set of technical, economic, and policy studies have been completed in Canada to determine the viability of a mobile service to satisfy Canada's requirements. This paper will present an overall review of these studies, give a rationale as to why narrowband technologies are necessary for the commercial viability of this service, and the approach taken in the development of these technologies. A brief review of activities and proposed mobile satellite systems in other areas besides North America is also given. The effect of an early entry by commercial interests (Telesat in Canada) will be examined including system parameters which require careful coordination within Canada and the U.S. operations in order to assure commercial viability in both countries. A review of some common requirements in the Canadian and U.S. systems will be discussed in order to standardize the system and equipment approaches for each country and provide mutual back-up in the event of a spacecraft anomaly. The trade-offs between the use of UHF (800 MHz) and L-Band (1.5 GHz) when used for true mobile applications are discussed. A hybrid system design is explored which would make the most appropriate use of both bands.

  8. European small geostationary communications satellites

    NASA Astrophysics Data System (ADS)

    Sun, Wei, , Dr.; Ellmers, Frank; Winkler, Andreas; Schuff, Herbert; Sansegundo Chamarro, Manuel Julián

    2011-04-01

    Hispasat Advanced Generation 1 (HAG1) is the first satellite using the SGEO platform, which is under the development in the ESA Artes-11 program. Since the last presentation in the IAC 2007, a European industrial consortium led by OHB has completed the mission and spacecraft design. The platform Preliminary Design Review has been carried out in May 2008. The customer for the first mission is a commercial operator—Hispasat. The contract was signed in December 2008 and the satellite will be launched in 2012. To give confidence to the customer, SGEO platform will use up to date flight proven technologies. HAG1 carries 20/24 Ku-band and 3/5 Ka-band transponders to provide commercial services. Some innovative payload technologies will also be flown on board of HAG1 to gain in-orbit heritage. SGEO has also been selected as the baseline platform for the ESA Data Relay Satellite (EDRS). Phase-A study has just kicked off in January 2009. The targeted launch date is 2013. Heinrich Hertz will also use the SGEO platform. Heinrich Hertz is funded by the German Space Agency (DLR) and provides flight opportunities for technologies and components developed by the German Space Industry. With the HAG1 contract in hand, and EDRS and Heinrich Hertz in the line, OHB with its partners has the confidence that it will be able to speed up the product development of the SGEO platform for potential customers in the commercial market. This paper will first present the updated platform design and the status of the product development will be followed with the introduction of innovative payload technologies on board the first mission—HAG1 and ended with the mission concepts of EDRS and Heinrich Hertz missions.

  9. FUSE satellite electrical power subsystem

    SciTech Connect

    Roufberg, L.; Noah, K.

    1998-07-01

    The Far Ultraviolet Spectroscopic Explorer (FUSE) satellite will be placed into a low earth orbit to investigate astrophysical processes related to the formation and development of the early universe. The FUSE satellite is considered a pathfinder for NASA's Mid-Class Explorers (MIDEX). To reduce mission cost and development time while delivering quality science, NASA has enforced strict cost caps with a clear definition of high-level science objectives. As a result, a significant design driver for the electrical power subsystem (EPS) was to minimize cost. The FUSE EPS is a direct energy transfer, unregulated bus architecture, with batteries directly on the bus and solar array power limted by pulse-width-modulated shunt regulators. The power subsystem electronics (PSE) contains circuitry to control battery charging, provide power to the loads, and provide fault protection. The electronics is based on the PSE which Orbital (formerly, Fairchild Space) designed and built for NASA/GSFC's XTE spacecraft. However, the FUSE PSE design incorporates a number of unique features to meet the mission requirements. To minimize size of the solar panels due to stowed attachment constraints, GaAs/Ge solar cells were selected. This is the first time this type of large area, thinned solar cell with integral bypass diodes are being used for a NASA LEO mission. The solar panels support a satellite load power of 520W. Nickel Cadmium (NiCd) batteries are used which are identical to the RADARSAT-I design, except for different temperature sensors. This is the first mission for which Orbital is using SAFT NiCd batteries. The spacecraft bus, including the EPS, has successfully completed environmental testing and has been delivered for instrument integration. Tradeoffs involved in designing the EPS and selecting components based on the requirements are discussed. Analyses including solar array and battery sizing and energy balance are presented in addition to results from testing the flight

  10. Cartography of irregularly shaped satellites

    NASA Technical Reports Server (NTRS)

    Batson, R. M.; Edwards, Kathleen

    1987-01-01

    Irregularly shaped satellites, such as Phobos and Amalthea, do not lend themselves to mapping by conventional methods because mathematical projections of their surfaces fail to convey an accurate visual impression of the landforms, and because large and irregular scale changes make their features difficult to measure on maps. A digital mapping technique has therefore been developed by which maps are compiled from digital topographic and spacecraft image files. The digital file is geometrically transformed as desired for human viewing, either on video screens or on hard copy. Digital files of this kind consist of digital images superimposed on another digital file representing the three-dimensional form of a body.

  11. NOAA's future GOES satellite program

    NASA Astrophysics Data System (ADS)

    Howard, Edward; Heymann, Roger; Dittberner, Gerald J.; Kirkner, Steven

    1996-10-01

    Future weather satellites for NOAA at geosynchronous orbit may be smaller, less costly, and developed by a different process than is currently done. This path is sometimes called the 'smaller, cheaper and faster' process being pursued by NASA. We believe in the future there will be less money, a focus on using the right technology and the desire to get the most value for the resources invested in space missions. In this paper we give an update on our progress to define future GOES. It will include our efforts to trade on user requirement early, to use evolutionary technology, and to consider new cost reduction and program management techniques.

  12. MEMOS - Mars Environment Monitoring Satellite

    NASA Astrophysics Data System (ADS)

    Ott, T.; Barabash, S.; von Schéele, F.; Clacey, E.; Pokrupa, N.

    2007-08-01

    The Swedish Institute of Space Physics (IRF) in cooperation with the Swedish Space Corporation (SSC) has conducted first studies on a Mars Environment Monitoring Satellite (MEMOS). The MEMOS microsatellite (mass < 20 kg) will accommodate four scientific instruments: solar EUV/UV monitor (SEM), solar wind monitor (SWIM), magnetometer (MAG) and radiation environment monitor (REM). The payload monitors the solar conditions at Mars and characterizes the Mars environment to support other missions and science investigations. Monitoring of the solar wind parameters (velocity, density, and field) is the key for any aeronomy and solar wind interaction mission at Mars. The solar EUV / UV (HeII 30.4 nm and HII 121.6 nm) flux monitoring is required for upper atmosphere / ionosphere studies. The radiation environment monitoring is needed to study space weather effects on the near-Mars environment as well as for the preparations for man-flights. MEMOS follows the design philosophy of a detached and autonomously flying instrument for achieving the mentioned objectives. It is intended to be carried "piggy-back" to Mars on a suitable mission. Potential missions are: ESA Mars orbiters within the NEXT or Cosmic Vision programs, NASA Mars orbiters, national / bilateral Mars missions. At Mars MEMOS is separated from its carrier (parent satellite) via the release mechanism implemented in the dual formation flight mission PRISMA. The separation will take place during the orbit insertion scenario of the parent satellite at Mars thus placing MEMOS in a highly elliptical orbit guarantying sufficient observation time in the solar wind. In orbit MEMOS will autonomously detumble and spin-up to ~1 rpm for reasons of stabilization and to fulfill instrument requirements. Such a low spin-rate is sufficient for a required inertial pointing accuracy of 2.5° because of the small external disturbance torques (< 10-7 Nm) predominant at Mars responsible for nutation and precession of the spin-axis. The

  13. Costing the satellite power system

    NASA Technical Reports Server (NTRS)

    Hazelrigg, G. A., Jr.

    1978-01-01

    The paper presents a methodology for satellite power system costing, places approximate limits on the accuracy possible in cost estimates made at this time, and outlines the use of probabilistic cost information in support of the decision-making process. Reasons for using probabilistic costing or risk analysis procedures instead of standard deterministic costing procedures are considered. Components of cost, costing estimating relationships, grass roots costing, and risk analysis are discussed. Risk analysis using a Monte Carlo simulation model is used to estimate future costs.

  14. Resolving Seamounts in Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Marks, K. M.; Smith, W. H.

    2006-12-01

    We have examined three factors influencing the use of satellite altimeter data to map seamounts and guyots in the deep ocean: (1) the resolution of seamount and guyot gravity anomalies by altimetry; (2) the non-linearity of the relationship between gravity and bathymetry; and (3) the homogeneity of the mass density within the seamount or guyot. When altimeter data are used to model the marine gravity anomaly field the result may have limited resolution due to noise levels in the altimeter data, track spacing of the satellite profiles, inclination angles of the orbits, and filters used to combine and interpolate the data (Sandwell and Smith, JGR, 1997). We compared the peak-to-trough amplitude of gravity anomalies in Sandwell and Smith`'s version 15.1 field to peak-to-trough amplitudes measured by gravimeters on board ships. The satellite gravity field amplitudes match ship measurements well over seamounts and guyots having volumes exceeding ~2000 km3. Over smaller volume seamounts, where the anomalies have most of their power at quite short wavelengths, the satellite field under-estimates the anomaly amplitude. If less filtering could be done, or a new mission with a lower noise level were flown, more of the anomalies associated with small seamounts might be resolved. Smith and Sandwell (Science, 1997) predicted seafloor topography from altimetric gravity assuming that the density of seafloor topography is nearly constant over ~100 km distances, and that the relationship between gravity and topography may be approximated by a liner filter over those distances. In fact, the true theoretical relationship is non-linear (Parker, Geophys. J. R. astr. Soc, 1972); it can be expressed as an N-th order expansion, with the N=1 term representing a linear filter and the N>1 terms accounting for higher-order corrections. We find that N=2 is a sufficient approximation at both seamounts and guyots. Constant density models of large volume guyots do not fit the observed gravity

  15. Satellite demodulator and telecommand decoder

    NASA Astrophysics Data System (ADS)

    Pereiradelucena, Antonio Macilio

    1986-11-01

    This work presents the design, analysis and test results of the BPSK/NRZ-L demodulator and telecommand decoder of the data collecting the satellite of Missao Espacial Completa Brasileira (MECB). The constraints imposed by the space application motivate the adoption of nonconventional solutions. Basically, the innovations are the parallel subcarrier and bit synchronization and the replacement of multipliers by exclusive-or gates operating on digital signals. These innovations offer advantages in speed, power consumption and reliability. A partial and original mathematical analysis of the adopted solutions is presented.

  16. Satellite spectra of heliumlike nickel

    SciTech Connect

    Hsuan, H.; Bitter, M.; Hill, K.W.; von Goeler, S. Grek, B.; Johnson, D.; Johnson, L.C.; Sesnic, S.; Bhalla, C.P.; Karim, K.R.

    1987-02-01

    Spectra of heliumlike nickel, NiXXVII, have been observed from Tokamak Fusion Test Reactor (TFTR) plasmas with a high resolution crystal spectrometer. The experimental arrangement permits simultaneous observation of the heliumlike resonance line, the intercombination and forbidden lines, and all the associated satellites due to transitions 1s/sup 2/nl - 1s2l'nl'' with N greater than or equal to 2. Relative wavelengths and line intensities can thus be determined very accurately. The observed spectral data are in good agreement with results from the present Hartree-Fock-Slater atomic model calculations and predictions from the Z-expansion method.

  17. Trends in NASA communication satellites.

    NASA Technical Reports Server (NTRS)

    Sivo, J. N.; Robbins, W. H.; Stretchberry, D. M.

    1972-01-01

    Discussion of the potential applications of satellite communications technology in meeting the national needs in education, health care, culture, and data transfer techniques. Experiments with the NASA ATS 1, 3 and 5 spacecraft, which are conducted in an attempt to satisfy such needs, are reviewed. The future needs are also considered, covering the requirements of multiple region coverage, communications between regions, large numbers of ground terminals, multichannel capability and high quality TV pictures. The ATS F and CTS spacecraft are expected to be available in the near future to expand experiments in this field.

  18. Fermilab's Satellite Refrigerator Expansion Engines

    SciTech Connect

    Peterson, Thomas J.

    1983-01-01

    Each of Fermilab's 24 satellite refrigerators includes two reciprocating expanders, a "wet" engine and a "dry" engine. The wet engines and all but eleven of the dry engines were manufactured by Koch Process Systems (Westboro, Massachusetts). These are basically Koch Model 1400 expaaders installed in cryostats designed by Fermilab. The other eleven dry engines are an in-hou~e design referred to as "Gardner-Fermi" engines since they evolved from the GX3-2500 engines purchas~d from Gardner Cryogenics. Table I surmnarizes the features of our three types of expanders....

  19. Data Recovery from SCATHA Satellite

    NASA Technical Reports Server (NTRS)

    Fennell, J. F.; Boyd, G. M.; Redding, M. T.; McNab, M. C.

    1997-01-01

    This document gives a brief description of the SCATHA (P78-2) satellite and consolidates into one location information relevant to the generation of the SCATHA Summary Data parameters for the European Space Agency (ESA), under ESTEC Contract No. 11006/94/NL/CC, and the National Aeronautics and Space Administration (NASA), under Grant No. NAGW-414 1. Included are descriptions of the instruments from which the Summary Data parameters are generated, their derivation, and archival. Any questions pertaining to the Summary Data parameters should be directed to Dr. Joseph Fennell.

  20. Multi-purpose satellite bus

    NASA Technical Reports Server (NTRS)

    Sakoda, Daniel; Agrawal, Brij N.

    1991-01-01

    The Multi-Purpose Satellite bus (MPS) can be used for a number of payloads which may require different orbits, pointing accuracy, and electrical power consumption. Specifically, it was designed to accommodate the Advanced Very High Resolution Radiometer and an EHF communication payload, both of which have a three-year life. The estimated beginning-of-life weight of the MPS bus is 150 kg. It can be launched by either the Pegasus ALV or the Taurus SSLV. Configuration requirements for the different missions are discussed.

  1. Solar power satellite cost estimate

    NASA Technical Reports Server (NTRS)

    Harron, R. J.; Wadle, R. C.

    1981-01-01

    The solar power configuration costed is the 5 GW silicon solar cell reference system. The subsystems identified by work breakdown structure elements to the lowest level for which cost information was generated. This breakdown divides into five sections: the satellite, construction, transportation, the ground receiving station and maintenance. For each work breakdown structure element, a definition, design description and cost estimate were included. An effort was made to include for each element a reference that more thoroughly describes the element and the method of costing used. All costs are in 1977 dollars.

  2. Interactions between satellites and plasma

    NASA Technical Reports Server (NTRS)

    Isensee, U.; Lehr, W.; Maassberg, H.

    1984-01-01

    The interactions of a spacecraft with the surrounding, streaming plasma were determined by the following effects: the fade out of the plasma in the wake of the probe, the emission of photoelectrons and secondary electrons, the differential charging of the surface of the probe, and a spatial potential distribution in the vicinity of the space probe. These effects and their importance are discussed and following plasma conditions are considered: (1) geostationary satellite orbits; (2) in the solar wind (HELIOS mission); and (3) in the ionosphere at an altitude of 250 km (the projected OSV on Spacelab). The fundamental models are reviewed.

  3. SATELLITE FORMATION from ancient massive rings

    NASA Astrophysics Data System (ADS)

    Crida, Aurélien; Charnoz, Sébastien

    2013-07-01

    When a planetary tidal disk - like Saturn's rings - spreads beyond the Roche radius (inside which planetary tides prevent aggregation), satellites form and migrate away. Here, we show that most regular satellites in the solar system probably formed in this way. According to our analytical model, when the spreading is slow, a retinue of satellites appear with masses increasing with distance to the Roche radius, in excellent agreement with Saturn's, Uranus', and Neptune's satellite systems. This suggests that Uranus and Neptune used to have massive rings that disappeared to give birth to most of their regular satellites. In contrast, when the spreading is fast, only one large satellite forms, as was the case for Pluto and Earth. This conceptually bridges the gap between terrestrial and giant planet systems. (Ref: Crida & Charnoz 2012, Science, 338, 1196-1199)

  4. Kagawa Satellite “STARS” in Shikoku

    NASA Astrophysics Data System (ADS)

    Nohmi, Masahiro; Yamamoto, Takeshi; Andatsu, Akira; Takagi, Yohei; Nishikawa, Yusuke; Kaneko, Takashi; Kunitom, Daisuke

    The Space Tethered Autonomous Robotic Satellite (STARS) is being developed in Kagawa University, and it will be launched by the H-IIA rocket by Japan Aerospace Exploration Agency (JAXA) in summer 2008. STARS is the first satellite developed in Shikoku, and its specific characteristics are: (i) mother and daughter satellites, which have basic satellite system respectively, and those are launched at the same time; (ii) large space system more than 5m by extending tether; (iii) robotic system, the daughter satellite controls its arm link and the mother satellite controls tether extension. Development of STARS in Kagawa University demonstrates space technology in local community, which has been considered to be a national project. Also, it promotes popularization, enlightenment, and understanding of space technology in local area of the Kagawa prefecture and around it.

  5. In search of satellites of minor planets

    NASA Astrophysics Data System (ADS)

    Maley, P. D.

    1980-12-01

    The detection of satellites of asteroids in observations of the occultation of stars is discussed. Anomalous occultation events recorded in addition to the possible discovery of a natural satellite of Herculina in 1978 are related, including the secondary occultation of Gamma Ceti by Hebe in March, 1977, a secondary occultation by Melpomene in December 1978, and unexplained occultations by Eros, Cybele and Metis. A procedure which may be used by amateur astronomers to provide reliable evidence for minor planet parasitic satellites is outlined, and the importance of multiple observations of stellar occultations by asteroids to the detection of parasitic satellites is emphasized. Additional observations supporting the existence of asteroid satellites are noted, and the factors casting doubt on the reality of the inferred satellites are pointed out.

  6. 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.

  7. ECS - The European Communication Satellite system

    NASA Astrophysics Data System (ADS)

    Wooster, C. B.

    1981-09-01

    The evolution of the European Communication Satellite system (ECS) is traced from feasibility studies in 1970 to the development and launch in 1978 of the Orbital Test Satellite (OTS) by the European Space Agency to prove the new satellite and radio transmission technology being used on ECS. This was followed by the establishment of 'Interim EUTELSAT' in 1979 as the organization to operate ECS. The satellite, which operates at 11/14 GHz, covers all the capitals in Europe via three spot beam antennas, supplemented by a 'Eurobeam' regional coverage antenna which extends the range to cover all of Europe and the Mediterranean basin. Telephony channels are transmitted digitally using time division multiple access (TDMA) with digital speech interpolation (DSI) to optimize satellite capacity. Television transmission is by analog FM over the Eurobeam antenna to North African as well as European capitals. System implications of TDMA operation are discussed, and the EUTELSAT policy for Special Services or satellite business systems is discussed.

  8. Secular motion around synchronously orbiting planetary satellites.

    PubMed

    Lara, Martin; San-Juan, Juan F; Ferrer, Sebastián

    2005-12-01

    We investigate the secular motion of a spacecraft around the natural satellite of a planet. The satellite rotates synchronously with its mean motion around the planet. Our model takes into account the gravitational potential of the satellite up to the second order, and the third-body perturbation in Hill's approximation. Close to the satellite, the ratio of rotation rate of the satellite to mean motion of the orbiter is small. When considering this ratio as a small parameter, the Coriolis effect is a first-order perturbation, while the third-body tidal attraction, the ellipticity effect, and the oblateness perturbation remain at higher orders. Then, we apply perturbation theory and find that a third-order approach is enough to show the influence of the satellite's ellipticity in the pericenter dynamics. Finally, we discuss the averaged system in the three-dimensional parametric space, and provide a global description of the flow. PMID:16396586

  9. Model-based satellite acquisition and tracking

    NASA Technical Reports Server (NTRS)

    Casasent, David; Lee, Andrew J.

    1988-01-01

    A model-based optical processor is introduced for the acquisition and tracking of a satellite in close proximity to an imaging sensor of a space robot. The type of satellite is known in advance, and a model of the satellite (which exists from its design) is used in this task. The model base is used to generate multiple smart filters of the various parts of the satellite, which are used in a symbolic multi-filter optical correlator. The output from the correlator is then treated as a symbolic description of the object, which is operated upon by an optical inference processor to determine the position and orientation of the satellite and to track it as a function of time. The knowledge and model base also serves to generate the rules used by the inference machine. The inference machine allows for feedback to optical correlators or feature extractors to locate the individual parts of the satellite and their orientations.

  10. Some Mathematical Problems of Satellite Networks

    NASA Technical Reports Server (NTRS)

    Lo, Martin

    1995-01-01

    Economic forces and technology development have made low-earth-orbit satellite constellations extremely attractive to the emergent personal communications industry. These constellations range from 2 to nearly 1000 satellites. Even though none of the constellations are as yet completely deployed, design on second generation constellations have already begun. The satellite coverage and network links provide some interesting mathematical problems. We examine some of the geometric and combinatorial problems associated with these networks.

  11. STS-5 deployment of communications satellites

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The Telesat Canada ANIK C-3 communications satellite rises from its protective 'cradle' (obscured by another such device in the foreground) in the cargo bay of the Space Shuttle Columbia. The empty, closed shield in the cargo bay (foreground) earlier had protected Satellite Business Systems (SBS-3) satellite. Both orbital maneuvering system (OMS) pods, part of the vertical tail and part of the wing stand out in this photo.

  12. A public service communications satellite user brochure

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The capabilities of a proposed communications satellite that would be devoted to experiments and demonstrations of various public services is described. A Public Service Communications Satellite study was undertaken at the NASA Goddard Space Flight Center (GSFC) to define the problems and opportunities of a renewed NASA role and the form such NASA involvement should take. The concept that has evolved has resulted from careful consideration of experiments that were already undertaken on existing satellites.

  13. Satellite system considerations for computer data transfer

    NASA Technical Reports Server (NTRS)

    Cook, W. L.; Kaul, A. K.

    1975-01-01

    Communications satellites will play a key role in the transmission of computer generated data through nationwide networks. This paper examines critical aspects of satellite system design as they relate to the computer data transfer task. In addition, it discusses the factors influencing the choice of error control technique, modulation scheme, multiple-access mode, and satellite beam configuration based on an evaluation of system requirements for a broad range of application areas including telemetry, terminal dialog, and bulk data transmission.

  14. Origin and Evolution of Saturn's Small Satellites

    NASA Astrophysics Data System (ADS)

    Charnoz, Sebastien; Salmon, J.; Crida, A.; Brahic, A.

    2009-09-01

    All Saturn’ small satellites, orbiting below Mimas'orbit, share some common physical and dynamical properties : they have strong water absorption bands (Poulet & Cuzzi, 2002 Icarus 160, 350-358, Cuzzi et al., in press) , they have strange and elongated shapes and are under dense (Charnoz et al, 2007 Science 318, 1622, Porco et al. 2007 Science 318, 1602). They are also dynamically coupled with Saturn rings. In addition, due to their small size, they should not be primordial because of the meteoroid bombardment. They dynamically evolve under the tidal torque of the planet and the rings, in addition to satellite's perturbations. A theory of their origin still needs to be done. We show in the present work that these small satellites may be the natural result of the viscous spreading of Saturn's rings. Using a new 1D coupled hydrodynamic + dynamical evolution code, we compute that the rings viscous spreading may naturally form a population of 10-50 km size satellites, with and orbital organisation similar to the today population of small satellites. Self-regulation processes are at work limiting the maximum mass of small satellite to about the mass of Janus, consistently with observations. This satellite formation scenario of a new kind (due to the viscous spreading of a disk) seems to explain the composition, the shape, the total mass, and the low density of Saturn's small satellites. It would give also an interesting explanation to the origin of the F ring. In conclusion, Saturn's small satellites may be considered as a specific category of satellites whose origin is very different either from Saturn's main satellites of Saturn's captured satellites. They could be the "children” of the rings.

  15. A SEARCH FOR SATELLITES AROUND CERES

    SciTech Connect

    Bieryla, A.; Parker, J. Wm.; Young, E. F.; Stern, S. A.; McFadden, L. A.; Russell, C. T.; Sykes, M. V.; Gladman, B.

    2011-06-15

    We conducted a satellite search around the dwarf planet 1 Ceres using Hubble Space Telescope and ground-based Palomar data. No candidate objects were found orbiting Ceres in its entire stability region down to {approx}500 km from the surface of Ceres. Assuming a satellite would have the same albedo as Ceres, which has a visual geometric albedo of 0.07-0.10, our detection limit is sensitive to satellites larger than 1-2 km in diameter.

  16. Coordinates of features on the Galilean satellites

    NASA Technical Reports Server (NTRS)

    Davies, M. E.; Katayama, F. Y.

    1980-01-01

    The coordinate systems of each of the Galilean satellites are defined and coordinates of features seen in the Voyager pictures of these satellites are presented. The control nets of the satellites were computed by means of single block analytical triangulations. The normal equations were solved by the conjugate iterative method which is convenient and which converges rapidly as the initial estimates of the parameters are very good.

  17. History of on-orbit satellite fragmentations

    NASA Technical Reports Server (NTRS)

    Nauer, David J.

    1992-01-01

    Since the first serious satellite fragmentation occurred in Jun. 1961, and instantaneously increased the total Earth satellite population by more than 400 percent, the issue of space operations within the finite region of space around the Earth has been the subject of increasing interest and concern. The prolific satellite fragmentations of the 1970's and the marked increase in the number of fragmentations in the 1980's served to widen international research into the characteristics and consequences of such events. Plans for large, manned space stations in the next decade and beyond demand a better understanding of the hazards of the dynamic Earth satellite population. The contribution of satellite fragmentations to the growth of the Earth satellite population is complex and varied. The majority of detectable fragmentation debris have already fallen out of orbit, and the effects of 40 percent of all fragmentations have completely disappeared. In this volume, satellite fragmentations are categorized by their assessed nature and to a lesser degree by their effect on the near-Earth space environment. A satellite breakup is the usually destructive disassociation of an orbital payload, rocket body, or structure, often with a wide range of ejecta velocities. A satellite breakup may be accidental or the result of intentional actions, e.g., due to a propulsion system malfunction or a space weapons test, respectively. An anomalous event is the unplanned separation, usually at low velocity, of one or more detectable objects from a satellite which remains essentially intact. Anomalous events can be caused by material deterioration of items such as thermal blankets, protective shields, or solar panels. As a general rule, a satellite breakup will produce considerably more debris, both trackable and non-trackable, than an anomalous event. From one perspective, satellite breakups may be viewed as a measure of the effects of man's activity on the environment, while anomalous

  18. Communications satellite no. 2 (CS-2)

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The purpose of the Japanese CS-2 satellite is to provide national communications and industrial communications, such as special emergency and remote communications, and to contribute to the development of technology pertaining to communications satellites. Description and operating parameters of the following satellite components are presented: structure, communications system, telemetry/command system, electric power system, attitude and antenna control system, secondary propulsion system, apogee motor, framework, and heat control system.

  19. Satellite radiation observations and climate theory

    NASA Technical Reports Server (NTRS)

    Ohring, G.; Gruber, A.

    1983-01-01

    The representative applications of satellite observations of the earth radiation budget in climate studies are discussed. Consideration is given to the use of satellite observational data for validating numerical estimates of the sensitivity of longwave radiation, surface temperature, and cloud amount to changes in the radiation budget. Particular emphasis is given to the application of satellite observations to the validation of temperature estimates obtained from the NOAA Seasonal Hemispheric Zonal Average Model (SZHAM).

  20. Microwave intersatellite links for communications satellites

    NASA Technical Reports Server (NTRS)

    Welti, G. R.

    1982-01-01

    Applications and interface requirements for intersatellite links (ISLs) between commercial communications satellites are reviewed, ranging from ISLs between widely separated satellites to ISLs between clustered satellites. On-board processing architectures for ISLs employing a variety of modulation schemes are described. These schemes include FM remodulation and QPSK regeneration in combination with switching and buffering. The various architectures are compared in terms of complexity, required performance, antenna size, mass, and power.

  1. Engineering calculations for communications satellite systems planning

    NASA Technical Reports Server (NTRS)

    Walton, E.; Aebker, E.; Mata, F.; Reilly, C.

    1991-01-01

    The final phase of a satellite synthesis project is described. Several methods for generating satellite positionings with improved aggregate carrier to interference characteristics were studied. Two general methods for modifying required separation values are presented. Also, two methods for improving aggregate carrier to interference (C/I) performance of given satellite synthesis solutions are presented. A perturbation of the World Administrative Radio Conference (WARC) synthesis is presented.

  2. Small Satellite Access of the Space Network

    NASA Technical Reports Server (NTRS)

    Horan, Stephen; Minnix, Timothy O.; Vigil, J. S.

    1999-01-01

    Small satellites have been perceived as having limited access to NASA's Space Network (SN). The potential for satellite access of the space network when the design utilizes a fixed antenna configuration and low-power, coded transmission is analyzed. From the analysis, satellites using this configuration in high-inclination orbits are shown to have a daily data throughput in the 100 to 1000 Mbit range using the multiple access communications service.

  3. Tethered satellite system dynamics and control

    NASA Technical Reports Server (NTRS)

    Musetti, B.; Cibrario, B.; Bussolino, L.; Bodley, C. S.; Flanders, H. A.; Mowery, D. K.; Tomlin, D. D.

    1990-01-01

    The first tethered satellite system, scheduled for launch in May 1991, is reviewed. The system dynamics, dynamics control, and dynamics simulations are discussed. Particular attention is given to in-plane and out-of-plane librations; tether oscillation modes; orbiter and sub-satellite dynamics; deployer control system; the sub-satellite attitude measurement and control system; the Aeritalia Dynamics Model; the Martin-Marietta and NASA-MSFC Dynamics Model; and simulation results.

  4. A study of satellite emergency locator systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Satellite emergency locator systems were studied. The objective of the study was to determine the feasibility and hardware requirements for satellite systems capable of identifying and locating the position emergency locator transmitters and emergency position indicating radio beacons. Both geosynchronous and near-polar-orbiting satellites were considered. One of the most important aspects of the study was to minimize the cost of the hardware required.

  5. A forecast of broadcast satellite communications

    NASA Technical Reports Server (NTRS)

    Martino, J. P.; Lenz, R. C., Jr.

    1977-01-01

    This paper presents forecasts of likely changes in broadcast satellite technology, the technology of ground terminals, and the technology of terrestrial communications competitive with satellites. The impacts of these changes in technology are then assessed, using a cross-impact model of U.S. domestic telecommunications, to determine the consequences of various possible changes in communications satellite technology. These consequences are discussed in terms of various possible services, for households, businesses, and specialized customers, which might become economically viable as a result of improvements in satellite technology.

  6. Mobile satellite service in the United States

    NASA Technical Reports Server (NTRS)

    Agnew, Carson E.; Bhagat, Jai; Hopper, Edwin A.; Kiesling, John D.; Exner, Michael L.; Melillo, Lawrence; Noreen, Gary K.; Parrott, Billy J.

    1988-01-01

    Mobile satellite service (MSS) has been under development in the United States for more than two decades. The service will soon be provided on a commercial basis by a consortium of eight U.S. companies called the American Mobile Satellite Consortium (AMSC). AMSC will build a three-satellite MSS system that will offer superior performance, reliability and cost effectiveness for organizations requiring mobile communications across the U.S. The development and operation of MSS in North America is being coordinated with Telesat Canada and Mexico. AMSC expects NASA to provide launch services in exchange for capacity on the first AMSC satellite for MSAT-X activities and for government demonstrations.

  7. Rotational dynamics of irregularly shaped natural satellites

    NASA Technical Reports Server (NTRS)

    Wisdom, Jack

    1987-01-01

    The rotational histories of irregularly shaped satellites are studied and are found to differ from the standard picture of tidal evolution of satellite rotations. Prior to capture into the synchronous rotation resonance, a narrow attitude-unstable chaotic zone is entered and the satellite begins to tumble chaotically. It is noted that enhanced dissipation of energy during the chaotic-tumbling phase may effect the orbital evolution. The theory suggests that, eventually, the rotation stays close to one of the accessible attitude-stable islands long enough for the weak tidal torque to remove the satellite from the chaotic zone.

  8. Advanced satellite design and ISDN compatibility

    NASA Astrophysics Data System (ADS)

    Pelton, Joseph N.

    1992-03-01

    The present evaluation of numerous strategies that can be pursued to upgrade satellite-based communications notes that such services will remain an important option for users even in a world of broadband Integrated Services Digital Network (ISDN) and Asynchronous Transfer Mode (ATM) services. Standards organizations concerned with satellite communications should accordingly develop ISDN and ATM standards that are compatible with satellites, fiber-optics, and hybrid systems, including those standards relating to improving satellite performance in such areas of strategic weakness as onboard processing and artificially intelligent ultrasmall aperture terminals.

  9. Placement of retroreflectors on the Lageos satellite

    NASA Technical Reports Server (NTRS)

    Moore, J. E.

    1976-01-01

    A model is presented for placing a large number of equal size holes in the surface of a spherical satellite. This problem differs from the classical mathematical problem of packing the maximum number of equal nonoverlapping circles on a sphere in that no hole can intersect the assembly joint at the satellite equator. The model was used during the design of Lageos to analyze the influence of the satellite diameter and hole size on the number of holes that could be placed on the satellite. The retroreflector placement pattern used in constructing Lageos was produced by the model.

  10. The tethered satellite electrodynamics experiment project

    NASA Technical Reports Server (NTRS)

    Price, John M.

    1988-01-01

    NASA and Italy's PSN have undertaken the Tethered Satellite Electrodynamics Experiment, in which two tethered bodies will be equipped with data-collecting scientific instruments, as the first stage of the development of the Tethered Satellite System that can be deployed by the Space Shuttle. The experiment will give attention to the electromagnetic interaction between the satellite/tether/orbiter system and the ambient space plasma, and should demonstrate the operation of both satellite- and Shuttle-borne electrodynamic instruments with a conductive tether.

  11. Small-satellite technology and applications III

    SciTech Connect

    Horais, B.J.

    1993-01-01

    This third conference on small-satellite applications has combined a number of significant and timely presentations on the status, in the US and on the international front, of this emerging industry. Presentations by all of the major Department of Defense activities in this field, including an overview of the ARPA CAMEO multispectral remote sensing satellite program, space activities at the Air Force Phillips Laboratory, and a space systems capabilities overview of the Naval Research Laboratory, are complemented by presentations from several international activities on their accomplishments and progress in the development of remote sensing satellite programs. For example: Spar Aerospace of Canada presented an overview of the progress they have made in establishing a space program through the use of small satellites, and the University of Surrey and Spar Aerospace provided an overview of the application of image compression schemes to imagery obtained from their UoSAT series of satellites. In addition, a number of papers were presented that summarize the state of technology in supporting activities, such as the development of the low-cost composite standardized satellite bus structures, accurate star trackers, and the application of JPEG and MPEG compression capabilities. Small-Satellite Technology and Applications III also addresses the business and cost estimating aspects of the emerging small-satellite industry as a means of increasing the overall awareness of the community in all aspects of developing a small-satellite remote sensing capability. Separate abstracts were prepared for 25 papers in this conference.

  12. Heterogeneity in the muscle satellite cell population

    PubMed Central

    Biressi, Stefano; Rando, Thomas A.

    2010-01-01

    Satellite cells, the adult stem cells responsible for skeletal muscle regeneration, are defined by their location between the basal lamina and the fiber sarcolemma. Increasing evidence suggests that satellite cells represent a heterogeneous population of cells with distinct embryological origin and multiple levels of biochemical and functional diversity. This review focuses on the rich diversity of the satellite cell population based on studies across species. Ultimately, a more complete characterization of the heterogeneity of satellite cells will be essential to understand the functional significance in terms of muscle growth, homeostasis, tissue repair, and aging. PMID:20849971

  13. Satellite ground-terminal user simulation

    NASA Technical Reports Server (NTRS)

    Shalkhauser, Mary Jo W.

    1988-01-01

    Realistic simulation of satellite communication systems and evaluation of satellite networking schemes require emulation of the systems's users. A laboratory model of a Ka-band satellite-switched time-division multiple-access (SS-TDMA) communication network, referred to as the System Integration, Test, and Evaluation (SITE) project, uses special bit-error-rate (BER) test sets to simulate the transmitting and receiving users of a communication network. The bit-error-rate test sets contain circuit boards that can be modified to create a variety of interfaces to satellite system ground terminals.

  14. Space Weather, Cosmic Rays, and Satellite Anomalies

    NASA Astrophysics Data System (ADS)

    Lev, Dorman

    Results are presented of the Satellite Anomaly Project, which aims to improve the methods of safeguarding satellites in the Earth’s magnetosphere from the negative effects of the space environment. Anomaly data from the USSR and Russian “Kosmos” series satellites in the period 1971-1999 are combined into one database, together with similar information on other spacecraft. This database contains, beyond the anomaly information, various characteristics of space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluencies of electrons and protons at different energies, high energy cosmic ray variations and other solar, interplanetary and solar wind data. A comparative analysis of the distribution of each of these parameters relative to satellite anomalies was carried out for the total number of anomalies (about 6000 events), and separately for high altitude orbit satellites ( 5000 events) and low altitude (about 800 events). No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and proton event onsets for high (>1500 km) and low (<1500 km) altitude orbits revealed a big difference in behavior. Satellites were divided into several groups according to their orbital characteristics (altitude and inclination). The relation of satellite anomalies to the environmental parameters was found to be different for various orbits, and this should be taken into account when developing anomaly frequency models. The preliminary anomaly frequency models are presented.

  15. Meteorological satellites in support of weather modification

    NASA Technical Reports Server (NTRS)

    Reynolds, D. W.; Vonder Haar, T. H.; Grant, L. O.

    1978-01-01

    During the past several years, many weather modification programs have been incorporating meteorological satellite data into both the operations and the analysis phase of these projects. This has occurred because of the advancement of the satellite as a mesoscale measurement platform, both temporally and spatially, and as the availability of high quality data has increased. This paper surveys the applications of meteorological satellite data to both summer and winter weather modification programs. A description of the types of observations needed by the programs is given, and an assessment of how accurately satellites can determine these necessary parameters is made.

  16. Communications satellites in non-geostationary orbits

    NASA Technical Reports Server (NTRS)

    Price, Kent M.; Doong, Wen; Nguyen, Tuan Q.; Turner, Andrew E.; Weyandt, Charles

    1988-01-01

    The design of a satellite communications system in an orbit lower than GEO is described. Two sun-synchronous orbits which lie in the equatorial plane have been selected: (1) the apogee at constant time-of-day equatorial orbit, a highly eccentric orbit with five revolutions per day, which allows 77-135 percent more satellite mass to be placed in orbit than for GEO; and (2) the sun-synchronous 12-hour equatorial orbit, a circular orbit with two revolutions per day, which allows 23-29 percent more mass. The results of a life cycle economic analysis illustrate that nongeostationary satellite systems could be competitive with geostationary satellite systems.

  17. Small satellite debris catalog maintenance issues

    NASA Technical Reports Server (NTRS)

    Jackson, Phoebe A.

    1991-01-01

    The United States Space Command (USSPACECOM) is a unified command of the Department of Defense, and one of its tasks is to detect, track, identify, and maintain a catalog of all man-made objects in Earth orbit. This task is called space surveillance, and the most important tool for space surveillance is the satellite catalog. The command's reasons for performing satellite catalog maintenance is presented. A satellite catalog is described, and small satellite-debris catalog-maintenance issues are identified. The underlying rationale is to describe the catalog maintenance services so that the members of the community can use them with assurance.

  18. Domestic satellite services for rural areas

    NASA Astrophysics Data System (ADS)

    Briskman, R. D.

    1984-03-01

    It is pointed out that rural areas can be served by a domestic satellite communications system in an efficient and economical manner. To accomplish such efficiency and economy, the engineering parameters of the satellite communications system must be analyzed and selected with a view toward achieving the desired performance at minimum total cost. The equipment for an entire rural satellite communication system serving 1200 communities can be acquired for approximately $200 million (1983 dollars). An identical system, however, could also be implemented at much lower capital costs by leasing space segment capacity from existing satellite systems (Briskman and Savage, 1983).

  19. Satellite mission scheduling algorithm based on GA

    NASA Astrophysics Data System (ADS)

    Sun, Baolin; Mao, Lifei; Wang, Wenxiang; Xie, Xing; Qin, Qianqing

    2007-11-01

    The Satellite Mission Scheduling problem (SMS) involves scheduling tasks to be performed by a satellite, where new task requests can arrive at any time, non-deterministically, and must be scheduled in real-time. This paper describes a new Satellite Mission Scheduling problem based on Genetic Algorithm (SMSGA). In this paper, it investigates algorithmic approaches for determining an optimal or near-optimal sequence of tasks, allocated to a satellite payload over time, with dynamic tasking considerations. The simulation results show that the proposed approach is effective and efficient in applications to the real problems.

  20. Live Satellite Communications... An Exciting Teaching Aid

    ERIC Educational Resources Information Center

    Journal of Aerospace Education, 1976

    1976-01-01

    Describes ways that orbiting satellites carrying amateur radios can be used in the classroom at various grade levels to supplement physics, mathematics, electronics, and social science curricula. (MLH)

  1. A Satellite Frost Forecasting System for Florida

    NASA Technical Reports Server (NTRS)

    Martsolf, J. D.

    1981-01-01

    Since the first of two minicomputers that are the main components of the satellite frost forecast system was delivered in 1977, the system has evolved appreciably. A geostationary operational environmental satellite (GOES) system provides the satellite data. The freeze of January 12-14, 1981, was documented with increasing interest in potential of such systems. Satellite data is now acquired digitally rather than by redigitizing the GOES-Tap transmissions. Data acquisition is now automated, i.e., the computers are programmed to operate the system with little, if any, operation intervention.

  2. The dynamics of Martian satellites from observations

    NASA Astrophysics Data System (ADS)

    Emelyanov, N. V.; Vashkovyak, S. N.; Nasonova, L. P.

    1993-01-01

    This paper deals with the study of the motion of Martian satellites and with the determination of kinematic and dynamic parameters describing this system of satellites and planet. The values of these parameters are found on the basis of all available data of ground-based and space-based observations of Phobos and Deimos. The original analytical theory of the motion of the satellites was used and the data set was wider than in similar papers of other authors. Thus, a new specified model of the motion of Mars' satellites has been constructed.

  3. Satellites at work (Space in the seventies)

    NASA Technical Reports Server (NTRS)

    Corliss, W. R.

    1971-01-01

    The use of satellites in the areas of communications, meteorology, geodesy, navigation, air traffic control, and earth resources technology is discussed. NASA contributions to various programs are reviewed.

  4. TUBSAT-1, satellite technology for educational purposes

    NASA Technical Reports Server (NTRS)

    Ginati, A.

    1988-01-01

    TUBSAT-1 (Technical University of Berlin Satellite) is an experimental low-cost satellite within the NASA Get Away Special (GAS) program. This project is being financed by the German BMFT (Federal Ministry for Research and Technology), mainly for student education. The dimensions and weight are determined by GAS requirements and the satellite will be ejected from the space shuttle into an approximately 300-km circular orbit. It is a sun/star oriented satellite with an additional spin stabilization mode. The first planned payload is to be used for observing flight paths of migratory birds from northern Europe to southern Africa and back.

  5. Integration of mobile satellite and cellular systems

    NASA Technical Reports Server (NTRS)

    Drucker, Elliott H.; Estabrook, Polly; Pinck, Deborah; Ekroot, Laura

    1993-01-01

    By integrating the ground based infrastructure component of a mobile satellite system with the infrastructure systems of terrestrial 800 MHz cellular service providers, a seamless network of universal coverage can be established. Users equipped for both cellular and satellite service can take advantage of a number of features made possible by such integration, including seamless handoff and universal roaming. To provide maximum benefit at lowest posible cost, the means by which these systems are integrated must be carefully considered. Mobile satellite hub stations must be configured to efficiently interface with cellular Mobile Telephone Switching Offices (MTSO's), and cost effective mobile units that provide both cellular and satellite capability must be developed.

  6. Advanced ISDN satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The research performed by GTE Government Systems and the University of Colorado in support of the NASA Satellite Communications Applications Research (SCAR) Program is summarized. Two levels of research were undertaken. The first dealt with providing interim services Integrated Services Digital Network (ISDN) satellite (ISIS) capabilities that accented basic rate ISDN with a ground control similar to that of the Advanced Communications Technology Satellite (ACTS). The ISIS Network Model development represents satellite systems like the ACTS orbiting switch. The ultimate aim is to move these ACTS ground control functions on-board the next generation of ISDN communications satellite to provide full-service ISDN satellite (FSIS) capabilities. The technical and operational parameters for the advanced ISDN communications satellite design are obtainable from the simulation of ISIS and FSIS engineering software models of the major subsystems of the ISDN communications satellite architecture. Discrete event simulation experiments would generate data for analysis against NASA SCAR performance measure and the data obtained from the ISDN satellite terminal adapter hardware (ISTA) experiments, also developed in the program. The Basic and Option 1 phases of the program are also described and include the following: literature search, traffic mode, network model, scenario specifications, performance measures definitions, hardware experiment design, hardware experiment development, simulator design, and simulator development.

  7. The Canadian mobile satellite program

    NASA Astrophysics Data System (ADS)

    Boudreau, P. M.; Breithaupt, R. W.; McNally, J. L.

    The progressions and selection of design features for the Canadian segment of a mobile satellite (MSAT) communications system are traced. The feasibility study for a satellite-based public and government mobile communications service to underserved areas was carried out between 1980-82. The results covered the market demand, commercial viability, user cost-benefit, and spacecraft concepts. A subsequent 2 yr study was initiated to proceed with project definition. A market of 1.1 million users was identified in all of Canada, with MSAT replacing other systems for 50 percent of the market. Operations would be in the 806-890 MHz range. Traffic will be routed through gateway links functioning in the 8/7 GHz SHF band while the mobile units will be connected through an 821-825 MHz up link and an 866-870 MH downlink. New technologies will be needed for a central control station, the gateway stations, and the base stations for the mobile radio service, the mobile user terminals, and data collection platforms.

  8. Platelet satellitism: an ultrastructural study.

    PubMed Central

    Payne, C. M.

    1981-01-01

    The ultrastructural morphology of platelet-polymorph (platelet-polymorphonuclear leukocyte) rosettes was investigated in EDTA-anticoagulated blood obtained from two patients who exhibited the phenomenon of platelet satellitism. Most of the platelet profiles were attached to the polymorph surface by broad areas of contact. Examination of these broad areas of contact at high magnification revealed an intercellular material of low electron density. This material appeared to form strands, which bridged the intercellular space and spanned the entire area formed by the apposing plasma membranes. Phagocytosis of entire platelets was only observed in 1 case. The platelet profiles that participated in rosette formation revealed a large number of glycogen particles, compared with unattached platelets. Ultrastructural examination of "stress" platelets obtained from five normal subjects treated with steroids similarly showed a large number of glycogen particles, although no rosette formation or phagocytosis of platelets was observed. The etiology of platelet satellitism is discussed. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:7223859

  9. Petite Amateur Navy Satellite (PANSAT)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The subsystem and structural design of the Naval Post Graduate School's Petite Amateur Navy Satellite (PANSAT) is described. The objectives of PANSAT are: (1) to provide an ideal educational tool for officer students; (2) to provide digital store-and-forward communications, or packet radio, for the amateur radio community; and (3) to provide a low-cost space-based platform for small experiments. PANSAT will be launched from the Shuttle at a nominal altitude of 200 nmi. and an inclination of at least 37 deg. Since there is no attitude control, eight dipole whip antennas will be used to provide isotropic ground coverage for communications. FM digital communications will be used with up-link and down-link on a single frequency in the amateur band of 144 to 146 MHz or 437 to 438 MHz. The satellite's communications subsystem, data processor and sequencer, power subsystem, structure subsystem, and experiment payload are described. The major experiment being considered will test the on-orbit annealing of radiation damaged solar cells.

  10. 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.

  11. Transiting Exoplanet Survey Satellite (TESS)

    NASA Technical Reports Server (NTRS)

    Ricker, G. R.; Clampin, M.; Latham, D. W.; Seager, S.; Vanderspek, R. K.; Villasenor, J. S.; Winn, J. N.

    2012-01-01

    The Transiting Exoplanet Survey Satellite (TESS) will discover thousands of exoplanets in orbit around the brightest stars in the sky. In a two-year survey, TESS will monitor more than 500,000 stars 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. No ground-based survey can achieve this feat. A large fraction of TESS target stars will be 30-100 times brighter than those observed by Kepler satellite, and therefore TESS . planets will be far easier to characterize with follow-up observations. TESS will make it 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. TESS will provide prime targets for observation with the James Webb Space Telescope (JWST), as well as other large ground-based and space-based telescopes of the future. TESS data will be released with minimal delay (no proprietary period), inviting immediate community-wide efforts to study the new planets. The TESS legacy will be a catalog of the very nearest and brightest main-sequence stars hosting transiting exoplanets, thus providing future observers with the most favorable targets for detailed investigations.

  12. Satellite operations support expert system

    NASA Technical Reports Server (NTRS)

    1985-01-01

    The Satellite Operations Support Expert System is an effort to identify aspects of satellite ground support activity which could profitably be automated with artificial intelligence (AI) and to develop a feasibility demonstration for the automation of one such area. The hydrazine propulsion subsystems (HPS) of the International Sun Earth Explorer (ISEE) and the International Ultraviolet Explorer (IUS) were used as applications domains. A demonstration fault handling system was built. The system was written in Franz Lisp and is currently hosted on a VAX 11/750-11/780 family machine. The system allows the user to select which HPS (either from ISEE or IUE) is used. Then the user chooses the fault desired for the run. The demonstration system generates telemetry corresponding to the particular fault. The completely separate fault handling module then uses this telemetry to determine what and where the fault is and how to work around it. Graphics are used to depict the structure of the HPS, and the telemetry values displayed on the screen are continually updated. The capabilities of this system and its development cycle are described.

  13. Environmentally induced discharges on satellites

    NASA Technical Reports Server (NTRS)

    Stevens, N. J.

    1982-01-01

    A discharge process whose trigger conditions are a negative exposed metallic surface surrounded by a less negative dielectric, and a large voltage gradient at a dielectric/metal interface is proposed. Analysis of SCATHA data for a discharge substantiates the postulation. Surface discharges cause a small transient charge transfer to space which results in voltage transients. A method of computing these transients, based on the charge lost through the capacitance to space and a fraction of charge stored in the dielectric at the discharge source was developed. It gives an estimate of the discharge transients at the discharge site, which is used as input for coupling code analysis of structure/system response. The transient computations were applied to a three-axis stabilized, geosynchronous satellite for both sunlight and eclipse charging. The energy of the transient pulses are about 1 mJ for sunlight discharge and 8 mJ for eclipse. Changing of selected coatings on the satellite would relieve the stress.

  14. Automated satellite telemetry processing system

    NASA Astrophysics Data System (ADS)

    Parunakian, David; Kalegaev, Vladimir; Barinova, Vera

    In this paper we describe the design and important implementation details of the new automated system for processing satellite telemetry developedat Skobeltsyn Institute of Nuclear Physics of Moscow State University (SINP MSU) . We discuss the most common tasks and pitfall for such systems built around data stream from a single spacecraft or a single instrument, and suggest a solution that allows to quickly develop telemetry processing modules and to integrate them with an existing polling mechanism, support infrastructure and data storage in Oracle or MySQL database systems. We also demonstrate the benefits of this approach using modules for processing three different spacecraft data streams: Coronas-Photon (2009-003A), Tatiana-2 (2009-049D) and Meteor-M no.1 (2009-049A). The data format and protocols used by each of these spacecraft have distinct peculiarities, which nevertheless did not pose a problem for integrating their modules into the main system. Remote access via web interface to Oracle databases and sophisticated visualization tools create a possibility of efficient scientific exploitation of satellite data. Such a system is already deployed at the web portal of the Space Monitoring Data Center (SMDC) of SINP MSU (http://smdc.sinp.msu.ru).

  15. The tectonics of icy satellites

    NASA Astrophysics Data System (ADS)

    Murchie, S. L.

    The formation of tectonic structures on icy satellites may have resulted from one or more of several geologic processes: global volume change due to internal temperature change, H2O-ice phase changes, or ice-silicate differentiation; mantle convection driven by thermal or compositional heterogeneities; tidal deformation; and impact-related processes including formation of fracture systems, seismic disruption of areas antipodal to impact sites, basin collapse, and global reorientation. Observed tectonic structures and their associated volcanic deposits are classified herein into six basic assemblages: (1) pervasive troughs and scarps occurring at globally coherent orientations; (2) throughgoing troughs and bands of troughs, generally associated with volcanic materials; (3) linear to curvilinear ridges; (4) volcanically modified systems of concentric and radial scarps and furrows; (5) regional volcanic and tectonic centers; and (6) grooved terrain intimately associated with light-colored volcanic deposits. Comparison of these assemblages with predicted manifestations of different geologic processes may lead to some understanding of the relationship of volcanic and tectonic features to the endogenic and exogenic processes that have affected icy satellites.

  16. Worldwide satellite market demand forecast

    NASA Technical Reports Server (NTRS)

    Bowyer, J. M.; Frankfort, M.; Steinnagel, K. M.

    1981-01-01

    The forecast is for the years 1981 - 2000 with benchmark years at 1985, 1990 and 2000. Two typs of markets are considered for this study: Hardware (worldwide total) - satellites, earth stations and control facilities (includes replacements and spares); and non-hardware (addressable by U.S. industry) - planning, launch, turnkey systems and operations. These markets were examined for the INTELSAT System (international systems and domestic and regional systems using leased transponders) and domestic and regional systems. Forecasts were determined for six worldwide regions encompassing 185 countries using actual costs for existing equipment and engineering estimates of costs for advanced systems. Most likely (conservative growth rate estimates) and optimistic (mid range growth rate estimates) scenarios were employed for arriving at the forecasts which are presented in constant 1980 U.S. dollars. The worldwide satellite market demand forecast predicts that the market between 181 and 2000 will range from $35 to $50 billion. Approximately one-half of the world market, $16 to $20 billion, will be generated in the United States.

  17. Iowa satellite project ISAT-1

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Satellite systems to date have been mainly scientific in nature. Only a few systems have been of direct use to the public such as for telephone or television transmission. Space enterprises have remained a mystery to the general public and beyond the reach of the small business community. The result is a less than supportive public when it comes to space activities. The purpose of the ISAT-1 program is to develop a small and relatively inexpensive satellite that will serve the State of Iowa, primarily for educational purposes. It will provide products, services, and activities that will be educational, practical, and useful for a large number for people. The emphasis is on public awareness, 'space literacy', and routine practical applications rather than high technology. The initial conceptual design phase was complete when the current team took over the project. Some areas of the conceptual design were taken a little farther, but for the most part this team started at the detailed design stage.

  18. Photometric Study of Uranian Satellites

    NASA Technical Reports Server (NTRS)

    Kesten, Philip R.

    1998-01-01

    The best summary of my work at NASA is expressed in the following abstract, submitted the Division for Planetary Science of the American Astronomical Society and to be presented at the annual meeting in Madison in October. We report photometric measurements of Uranian satellites Miranda, Ariel, Umbriel and Titania (10.4 Aug. 1995), and Neptune's satellite Triton (21.2 Sept. 1995) with the infrared camera (IRCAM) and standard J (1.13 - 1.42 microns), H (1.53 - 1.81 microns), and K (2.00 - 2.41 microns) filters at the 3.8-m UKIRT telescope on Mauna Kea. The individual images frames are 256 x 256 pixels with a platescale of .286 arcsec/pixel, resulting in a 1.22 arc min field of view. This summer brought the IR photometry measurements nearly to a close. As indicated by the abstract above, I will present this work at the annual DPS meeting in October. In anticipation of the opening of the new Carl Sagan Laboratory for Cosmochemisty, of which I will be a participating member, I also devoted a considerable fraction of the summer to learning the biochemistry which underlies the experiments to be conducted. To put the end of the summary close to the beginning, it was a most productive summer.

  19. Doppler factors in satellite-to-satellite tracking. [with relativistic effects

    NASA Technical Reports Server (NTRS)

    Marini, J. W.

    1974-01-01

    The Doppler factors occurring in range rate satellite-to-satellite tracking measurements are derived with special relativistic effects included. The error resulting from the use of simplified expressions for these factors is discussed.

  20. Interim Service ISDN Satellite (ISIS) simulator development for advanced satellite designs and experiments

    NASA Technical Reports Server (NTRS)

    Pepin, Gerard R.

    1992-01-01

    The simulation development associated with the network models of both the Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures is documented. The ISIS Network Model design represents satellite systems like the Advanced Communications Technology Satellite (ACTS) orbiting switch. The FSIS architecture, the ultimate aim of this element of the Satellite Communications Applications Research (SCAR) Program, moves all control and switching functions on-board the next generation ISDN communications satellite. The technical and operational parameters for the advanced ISDN communications satellite design will be obtained from the simulation of ISIS and FSIS engineering software models for their major subsystems. Discrete event simulation experiments will be performed with these models using various traffic scenarios, design parameters, and operational procedures. The data from these simulations will be used to determine the engineering parameters for the advanced ISDN communications satellite.