Advanced communication satellites worldwide - Satellites of opportunity for the ACTS mobile terminal

NASA Technical Reports Server (NTRS)

Girardey, Catherine C.

1993-01-01

Space agencies worldwide are involved in advanced satellite communication systems. This paper presents an overview of these satellites and related technologies in the U.S., Europe, and Japan. They are geostationary satellites using high frequency bands such as K/Ka (20/30 GHz) and O-band (millimeter wave), as well as optical frequencies. The similarity of these programs demonstrate a common interest to develop large capacity satellite communication systems, and shows that closer international cooperation could be set up. The ACTS Mobile Terminal (AMT) project discussed here is such an example. The AMT's compatibility with satellites other than ACTS has been studied, and a proposed common experiment is presented here. The Japanese Engineering Test Satellite ETS-VI has been identified as the best initial 'satellite of opportunity' for AMT in this preliminary assessment.

Meteorological Measurements from Satellite Platforms. [stability and control of flexible stochastic satellites

NASA Technical Reports Server (NTRS)

Suomi, V. E.

1975-01-01

The stability of stochastic satellites and the stability and control of flexible satellites were investigated. The effects of random environmental torques and noises in the moments of inertia of spinning and three-axes stabilized satellites were first compared analytically by four methods and by analog simulations. Among the analytical methods, it was shown that the Fokker-Planck formulation yields predictions which most coincide with the simulation results. It was then shown that the required stability criterion of a satellite is quite different from that obtained by a deterministic approach, under the assumption that the environmental and control torques experienced by the satellite are random. Finally, it was demonstrated that, by monitoring the deformations of the flexible elements of a satellite, the effectiveness of the satellite control system can be increased considerably.

GOES West - Western Region WFO Satellite Imagery - Satellite Products and

Science.gov Websites

Services Division - Office of Satellite and Product Operations Skip Navigation Link NESDIS banner image and link to NESDIS link to the NOAA Home page Link to the National Environmental Satellite , Data, and Information Service Home Page Default Office of Satellite and Product Operations banner image

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.

NOAASIS (NOAA Satellite Information System) Home Page - Office of Satellite

Science.gov Websites

and Product Operations » DOC » NOAA » NESDIS » NOAASIS NOAA Satellite Information System Organizational Links National Environmental Satellite, Data, and Information Service (NESDIS) Office of Satellite ): Information and specific ground project support data for the Direct Broadcast Community from JPSS supported

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.

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.

Compendium of meteorological satellites and instrumentation. [US, USSR, UK, and French satellites

NASA Technical Reports Server (NTRS)

Stoldt, N. W.; Havanac, P. J.

1973-01-01

Pertinent information is presented for 98 launched and planned satellites of the U.S., U.K., U.S.S.R., and France, as well as their over 200 meteorological experiments or instruments. Summary information is provided for both operational and research satellites. Three major sections include: (1) an overview by country, of the various series of meteorological satellite programs; (2) brief descriptions of the satellites and their experiments; and (3) an extensive bibliography. A glossary of acronyms and two indexes for cross-referencing are also included. In addition, various tables and figures presenting satellite operating times, data coverage, location of launch sites, and descriptions of the launch vehicles used to orbit the meteorological satellites are given.

Ionospheric range-rate effects in satellite-to-satellite tracking

NASA Technical Reports Server (NTRS)

Lipofsky, J. R.; Bent, R. B.; Llewellyn, S. K.; Schmid, P. E.

1977-01-01

Investigation of ionospheric range and range-rate corrections in satellite-to-satellite tracking were investigated. Major problems were cited and the magnitude of errors that have to be considered for communications between satellites and related experiments was defined. The results point to the need of using a sophisticated modeling approach incorporating daily solar data, and where possible actual ionospheric measurements as update information, as a simple median model cannot possibly account for the complex interaction of the many variables. The findings provide a basis from which the residual errors can be estimated after ionospheric modeling is incorporated in the reduction. Simulations were performed for satellites at various heights: Apollo, Geos, and Nimbus tracked by ATS-6; and in two different geometric configurations: coplanar and perpendicular orbits.

Relative tracking control of constellation satellites considering inter-satellite link

NASA Astrophysics Data System (ADS)

Fakoor, M.; Amozegary, F.; Bakhtiari, M.; Daneshjou, K.

2017-11-01

In this article, two main issues related to the large-scale relative motion of satellites in the constellation are investigated to establish the Inter Satellite Link (ISL) which means the dynamic and control problems. In the section related to dynamic problems, a detailed and effective analytical solution is initially provided for the problem of satellite relative motion considering perturbations. The direct geometric method utilizing spherical coordinates is employed to achieve this solution. The evaluation of simulation shows that the solution obtained from the geometric method calculates the relative motion of the satellite with high accuracy. Thus, the proposed analytical solution will be applicable and effective. In the section related to control problems, the relative tracking control system between two satellites will be designed in order to establish a communication link between the satellites utilizing analytical solution for relative motion of satellites with respect to the reference trajectory. Sliding mode control approach is employed to develop the relative tracking control system for body to body and payload to payload tracking control. Efficiency of sliding mode control approach is compared with PID and LQR controllers. Two types of payload to payload tracking control considering with and without payload degree of freedom are designed and suitable one for practical ISL applications is introduced. Also, Fuzzy controller is utilized to eliminate the control input in the sliding mode controller.

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.

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.

Satellite image collection optimization

NASA Astrophysics Data System (ADS)

Martin, William

2002-09-01

Imaging satellite systems represent a high capital cost. Optimizing the collection of images is critical for both satisfying customer orders and building a sustainable satellite operations business. We describe the functions of an operational, multivariable, time dynamic optimization system that maximizes the daily collection of satellite images. A graphical user interface allows the operator to quickly see the results of what if adjustments to an image collection plan. Used for both long range planning and daily collection scheduling of Space Imaging's IKONOS satellite, the satellite control and tasking (SCT) software allows collection commands to be altered up to 10 min before upload to the satellite.

Small satellite product assurance

NASA Astrophysics Data System (ADS)

Demontlivault, J.; Cadelec, Jacques

1993-01-01

In order to increase the interest in small satellites, their cost must be reduced; reducing product assurance costs induced by quality requirements is a major objective. For a logical approach, small satellites are classified in three main categories: satellites for experimental operations with a short lifetime, operational satellites manufactured in small mass with long lifetime requirements, operational satellites (long lifetime required), of which only a few models are produced. The various requirements as regards the product assurance are examined for each satellite category: general requirements for space approach, reliability, electronic components, materials and processes, quality assurance, documentation, tests, and management. Ideal product assurance system integrates quality teams and engineering teams.

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.

Determination of the number of navigation satellites within satellite acquisition range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurenkov, Vladimir I., E-mail: kvi.48@mail.ru, E-mail: ask@ssau.ru; Kucherov, Alexander S., E-mail: kvi.48@mail.ru, E-mail: ask@ssau.ru; Gordeev, Alexey I., E-mail: exactoone@yahoo.com

2014-12-10

The problem of determination of the number of navigation satellites within acquisition range with regard to antenna systems configuration and stochastic land remote sensing satellite maneuvers is the subject considered in the paper. Distribution function and density function of the number of navigation satellites within acquisition range are obtained.

TDF-1, The French Broadcasting Satellite (TDF-1, Satellite Francais de Radiodiffusion),

DTIC Science & Technology

1982-04-22

defines the general directions of the program and gives the necessary directives to a joint project directorate in Munich, Germany ( French projects ...AD-A117 961 NAVAL ZNTELIGENC SUPPORT CENTER WASHINGTON DC TRAN-(ITC F/0 17/2 TOF-Il, THE FRENCH BROADCASTING SATELLITE (TDP-I. SATELLITE PRAN-ETC(U...8201/80A UNCLASSIFIED TITLE: TDF-1, The French Broadcasting Satellite TDF 1, satellite francais de radiodiffusion AUTHOR(S) AND/OR EDITOR(S): C

LARES Laser Relativity Satellite

NASA Astrophysics Data System (ADS)

Ciufolini, Ignazio; et al.

2011-05-01

After almost three decades since the first idea of launching a passive satellite to measure gravitomagnetism, launch of LARES satellite is approaching. The new developed VEGA launcher will carry LARES in a nominally circular orbit at 1450 km altitude. This satellite, along with the two LAGEOS satellites, will allow to improve a previous measurement of the Lense-Thirring effect by a factor of 10. This important achievement will be a result of the idea of combining orbital parameters of a constellation of laser ranging satellites along with a specific design of LARES satellite. Other key points of the experiment are: the ever improving knowledge of the gravitational field of Earth, in particular the lower degree even zonal harmonics with GRACE satellites, and an accurate estimate of all the classical perturbations such as atmospheric drag and solar radiation pressure. In the paper both the scientific aspects as well as the design consideration will be described

Space Solar Power Satellite Systems, Modern Small Satellites, and Space Rectenna

NASA Astrophysics Data System (ADS)

Bergsrud, Corey Alexis Marvin

Space solar power satellite (SSPS) systems is the concept of placing large satellite into geostationary Earth orbit (GEO) to harvest and convert massive amounts of solar energy into microwave energy, and to transmit the microwaves to a rectifying antenna (rectenna) array on Earth. The rectenna array captures and converts the microwave power into usable power that is injected into the terrestrial electric grid for use. This work approached the microwave power beam as an additional source of power (with solar) for lower orbiting satellites. Assuming the concept of retrodirectivity, a GEO-SSPS antenna array system tracks and delivers microwave power to lower orbiting satellites. The lower orbiting satellites are equipped with a stacked photovoltaic (PV)/rectenna array hybrid power generation unit (HPGU) in order to harvest solar and/or microwave energy for on-board use during orbit. The area, and mass of the PV array part of the HPGU was reduced at about 32% beginning-of-life power in order to achieve the spacecraft power requirements. The HPGU proved to offer a mass decrease in the PGU, and an increase in mission life due to longer living component life of the rectenna array. Moreover, greater mission flexibility is achieved through a track and power delivery concept. To validate the potential advantages offered by a HPGU, a mission concept was presented that utilizes modern small satellites as technology demonstrators. During launch, a smaller power receiving "daughter" satellite sits inside a larger power transmitting "mother" satellite. Once separated from the launch vehicle the daughter satellite is ejected away from the mother satellite, and each satellite deploys its respective power transmitting or power receiving hardware's for experimentation. The concept of close proximity mission operations between the satellites is considered. To validate the technology of the space rectenna array part of the HPGU, six milestones were completed in the design. The first

SatelliteDL: a Toolkit for Analysis of Heterogeneous Satellite Datasets

NASA Astrophysics Data System (ADS)

Galloy, M. D.; Fillmore, D.

2014-12-01

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

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.

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.

The dynamic phenomena of a tethered satellite: NASA's first Tethered Satellite Mission, TSS-1

NASA Technical Reports Server (NTRS)

Ryan, R. S.; Mowery, D. K.; Tomlin, D. D.

1993-01-01

The tethered satellite system (TSS) was envisioned as a means of extending a satellite from its base (space shuttle, space station, space platform) into a lower or higher altitude in order to more efficiently acquire data and perform science experiments. This is accomplished by attaching the satellite to a tether, deploying it, then reeling it in. When its mission is completed, the satellite can be returned to its base for reuse. If the tether contains a conductor, it can also be used as a means to generate and flow current to and from the satellite to the base. When current is flowed, the tether interacts with the Earth's magnetic field, deflecting the tether. When the current flows in one direction, the system becomes a propulsive system that can be used to boost the orbiting system. In the other direction, it is a power generating system. Pulsing the current sets up a dynamic oscillation in the tether, which can upset the satellite attitude and preclude docking. A basic problem occurs around 400-m tether length, during satellite retrieval when the satellite's pendulous (rotational) mode gets in resonance with the first lateral tether string mode. The problem's magnitude is determined by the amount of skiprope present coming into this resonance condition. This paper deals with the tethered satellite, its dynamic phenomena, and how the resulting problems were solved for the first tethered satellite mission (TSS-1). Proposals for improvements for future tethered satellite missions are included. Results from the first tethered satellite flight are summarized.

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

Healthy satellites provide quality service

NASA Astrophysics Data System (ADS)

Margittai, Paul

The procedures used by Telesat Canada to ensure the performance of Anik satellites is described. At the Satellite Telemetry, Tracking and Command station, each Anik satellite has its own dedicated antenna. Telemetered information from the satellites is received, processed and forwarded to the Satellite Control Center. There the satellite controllers issue all commands to the satellites, and continually monitor the telemetered data. These data, describing the state of health of the satellites, are then analyzed by engineering specialists. The satellites are held in their precise orbital positions by means of specially developed software. The Anik C and D satellites employ travelling wave tube amplifiers (TWTAs) in the transpounder channels. The TWTA saturated flux density (SFD) and equivalent isotropic radiated power (EIRP) are regularly measured and their trends scrutinized. This ensures that customers receive the radio frequency power needed for high-quality service. The satellite electrical power is supplied by the solar cell array and batteries. Power system performance is evaluated regularly to ensure that power is available to operate the required number of TWTAs. In addition to rain-fades, short service interruptions can be caused by high voltage trip-offs of TWTAs, and by electrostatic discharge related anomalies. To minimize these interruptions, Telesat ensures that the satellite controllers are fully trained and prepared for any eventuality, and the relevant operational procedures are continually refined. A fully trained staff of satellite controllers keep interruptions caused by high voltage trip-offs of TWTAs and by electrostatic discharge to a minimum.

Tethered satellite control mechanism

NASA Technical Reports Server (NTRS)

Kyrias, G. M.

1983-01-01

The tethered satellite control mechanisms consist of four major subsystems. The reel drive mechanism stores the tether. It is motor driven and includes a level wind to uniformly feed the tether to the reel. The lower boom mechanism serves two primary functions: (1) it measures tether length and velocity as the tether runs through the mechanism, and (2) it reads the tether tension at the reel. It also provides change the direction for the tether from the reel to the upper boom mechanism. The deployment boom positions the upper boom mechanism with satellite out of the cargo bay. The deployment function places the 500-kg satellite 20 m away from the Space Shuttle (producing a small natural gravity gradient force), impacts an initial velocity to the satellite for deployment, and allows for satellite docking at a safe distance from the body of the Space Shuttle. The upper boom mechanism (UBM) services three functions: (1) it provides tether control to the satellite as the satellite swings in and out of plane; (2) it reads tether tension in the low range during the early deployment and final retrieval parts of the mission; and (3) it produces additional tether tension at the reel when tether tension to the satellite is in the low range.

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

NASA Astrophysics Data System (ADS)

Johnson, N. L.

1983-02-01

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

Three small deployed satellites

NASA Image and Video Library

2012-10-04

ISS033-E-009282 (4 Oct. 2012) --- Several tiny satellites are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module’s robotic arm on Oct. 4, 2012. Japan Aerospace Exploration Agency astronaut Aki Hoshide, flight engineer, set up the satellite deployment gear inside the lab and placed it in the Kibo airlock. The Japanese robotic arm then grappled the deployment system and its satellites from the airlock for deployment. Earth’s horizon and the blackness of space provide the backdrop for the scene.

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.

Gravimetric geodesy and sea surface topography studies by means of satellite-to-satellite tracking and satellite altimetry

NASA Technical Reports Server (NTRS)

Siry, J. W.

1972-01-01

A satellite-to-satellite tracking experiment is planned between ATS-F and GEOS-C with a range accuracy of 2-meters and a range rate accuracy of 0.035 centimeters per second for a 10-second integration time. This experiment is planned for 1974. It is anticipated that it will improve the spatial resolution of the satellite geoid by half an order of magnitude to about 6 degrees. Longer integration times should also permit a modest increase in the acceleration resolution. Satellite altimeter data will also be obtained by means of GEOS-C. An overall accuracy of 5-meters in altitude is the goal. The altimeter, per se, is expected to have an instrumental precision of about 2 meters, and an additional capability to observe with a precision of about 0.2 meters for limited periods.

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.

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.

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.

JPSS Preparations at the Satellite Proving Ground for Marine, Precipitation, and Satellite Analysis

NASA Technical Reports Server (NTRS)

Folmer, Michael J.; Berndt, E.; Clark, J.; Orrison, A.; Kibler, J.; Sienkiewicz, J.; Nelson, J.; Goldberg, M.; Sjoberg, W.

2016-01-01

The ocean prediction center at the national hurricane center's tropical analysis and forecast Branch, the Weather Prediction center and the Satellite analysis branch of NESDIS make up the Satellite Proving Ground for Marine, Precipitation and Satellite Analysis. These centers had early exposure to JPSS products using the S-NPP Satellite that was launched in 2011. Forecasters continue to evaluate new products in anticipation for the launch of JPSS-1 sometime in 2017.

Three small deployed satellites

NASA Image and Video Library

2012-10-04

ISS033-E-009286 (4 Oct. 2012) --- Several tiny satellites are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module’s robotic arm on Oct. 4, 2012. Japan Aerospace Exploration Agency astronaut Aki Hoshide, flight engineer, set up the satellite deployment gear inside the lab and placed it in the Kibo airlock. The Japanese robotic arm then grappled the deployment system and its satellites from the airlock for deployment. A portion of the station’s solar array panels and a blue and white part of Earth provide the backdrop for the scene.

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.

Three small deployed satellites

NASA Image and Video Library

2012-10-04

ISS033-E-009285 (4 Oct. 2012) --- Several tiny satellites are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module’s robotic arm on Oct. 4, 2012. Japan Aerospace Exploration Agency astronaut Aki Hoshide, flight engineer, set up the satellite deployment gear inside the lab and placed it in the Kibo airlock. The Japanese robotic arm then grappled the deployment system and its satellites from the airlock for deployment. A portion of the station’s solar array panels and a blue and white part of Earth provide the backdrop for the scene.

Plan of Time Management of Satellite Positioning System using Quasi-zenith Satellite

NASA Astrophysics Data System (ADS)

Takahashi, Yasuhiro; Fujieda, Miho; Amagai, Jun; Yokota, Shoichiro; Kimura, Kazuhiro; Ito, Hiroyuki; Hama, Shin'ichi; Morikawa, Takao; Kawano, Isao; Kogure, Satoshi

The Quasi-Zenith satellites System (QZSS) is developed as an integrated satellite service system of communication, broadcasting and positioning for mobile users in specified regions of Japan from high elevation angle. Purposes of the satellite positioning system using Quasi-Zenith satellite (QZS) are to complement and augment the GPS. The national institutes concerned have been developing the positioning system using QZS since 2003 and will carry out experiments and researches in three years after the launch. In this system, National Institute of Information and Communications Technology (NICT) is mainly in charge of timing system for the satellite positioning system using QZS, such as onboard hydrogen maser atomic clock and precise time management system of the QZSS. We started to develop the engineering model of the time management system for the QZSS. The time management system for the QZSS will be used to compare time differences between QZS and earth station as well as to compare between three onboard atomic clocks. This paper introduces time management of satellite positioning system using the QZSS.

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…

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.

[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…

Satellite-Delivered Learning.

ERIC Educational Resources Information Center

Arnall, Gail C.

1987-01-01

Discusses the application of satellite information delivery to training. Describes a new trend, horizontal programming. Also discusses vertical programming and in-house production of training materials. Lists vendors of satellite-based training. (CH)

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…

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

Utilizing a TDRS satellite for direct broadcast satellite-radio propagation experiments and demonstrations

NASA Technical Reports Server (NTRS)

Hollansworth, James E.

1993-01-01

The NASA/VOA Direct Broadcast Satellite-Radio (DBS-R) Program will be using a NASA Tracking Data Relay Satellite (TDRS) satellite at 62 deg. West longitude to conduct live satellite S-band propagation experiments and demonstrations of satellite sound broadcasting over the next two years (1993-1994). The NASA/VOA DBS-R program has applied intensive effort to garner domestic and international support for the DBS-R concept. An S-band DBS-R allocation was achieved for Region 2 at WARC-92 held in Spain. With this allocation, the DBS-R program now needs to conduct S-band propagation experiments and systems demonstrations that will assist in the development of planning approaches for the use of Broadcast Satellite Service (Sound) frequency bands prior to the planning conference called for by WARC-92. These activities will also support receiver concept development applied to qualities ranging from AM to Monophonic FM, Stereophonic FM, Monophonic CD, and Stereophonic CD quality.

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.

On-orbit checkout study. [for the synchronous meteorological satellite and the technology demonstration satellite

NASA Technical Reports Server (NTRS)

Pritchard, E. I.

1977-01-01

The spaceborne testing equipment carried by the orbiter and the measuring equipment onboard the satellite (telemetry) is tested to verify that each is operating satisfactorily. The satellite command system is also checked. Thermal stabilization with the satellite in the orbiter shadow is achieved in six to eight hours. Satellite subsystem tests are run, and thermal control by heaters is checked. Thermal stabilization with the satellite exposed to the sun (when the orbiter is in sunlight) is again achieved in an estimated six to eight hours. Subsystem tests are again run in the hot condition, and heat rejection tests are made.

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.

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

Laser Geodynamics Satellite (LAGEOS)

NASA Image and Video Library

2016-05-04

This 1975 NASA video highlights the development of LAser GEOdynamics Satellite (LAGEOS I) developed at NASA's Marshall Space Flight Center in Huntsville, Alabama. LAGEOS I is a passive satellite constructed from brass and aluminum and contains 426 individual precision reflectors made from fused silica glass. The mirrored surface of the satellite was designed to reflect laser beams from ground stations for accurate ranging measurements. LAGEOS I was launched on May 4, 1976 from Vandenberg Air Force Base, California. The two-foot diameter, 900-pound satellite orbited the Earth from pole to pole, measuring the movements of the Earth's surface relative to earthquakes, continental drift, and other geophysical phenomena. Scientists at NASA's Marshall Space Flight Center in Huntsville, Alabama came up with the idea for the satellite and built it at the Marshall Center.

Full Service ISDN Satellite (FSIS) network model for advanced ISDN satellite design and experiments

NASA Technical Reports Server (NTRS)

Pepin, Gerard R.

1992-01-01

The Full Service Integrated Services Digital Network (FSIS) network model for advanced satellite designs describes a model suitable for discrete event simulations. A top down model design uses the Advanced Communications Technology Satellite (ACTS) as its basis. The ACTS and the Interim Service ISDN Satellite (ISIS) perform ISDN protocol analyses and switching decisions in the terrestrial domain, whereas FSIS makes all its analyses and decisions on-board the ISDN satellite.

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.

Estimating Density Using Precision Satellite Orbits from Multiple Satellites

NASA Astrophysics Data System (ADS)

McLaughlin, Craig A.; Lechtenberg, Travis; Fattig, Eric; Krishna, Dhaval Mysore

2012-06-01

This article examines atmospheric densities estimated using precision orbit ephemerides (POE) from several satellites including CHAMP, GRACE, and TerraSAR-X. The results of the calibration of atmospheric densities along the CHAMP and GRACE-A orbits derived using POEs with those derived using accelerometers are compared for various levels of solar and geomagnetic activity to examine the consistency in calibration between the two satellites. Densities from CHAMP and GRACE are compared when GRACE is orbiting nearly directly above CHAMP. In addition, the densities derived simultaneously from CHAMP, GRACE-A, and TerraSAR-X are compared to the Jacchia 1971 and NRLMSISE-00 model densities to observe altitude effects and consistency in the offsets from the empirical models among all three satellites.

JEMRMS Small Satellite Deployment Observation

NASA Image and Video Library

2012-10-04

ISS033-E-009334 (4 Oct. 2012) --- Several tiny satellites are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module’s robotic arm on Oct. 4, 2012. Japan Aerospace Exploration Agency astronaut Aki Hoshide, flight engineer, set up the satellite deployment gear inside the lab and placed it in the Kibo airlock. The Japanese robotic arm then grappled the deployment system and its satellites from the airlock for deployment.

JEMRMS Small Satellite Deployment Observation

NASA Image and Video Library

2012-10-04

ISS033-E-009458 (4 Oct. 2012) --- Several tiny satellites are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module’s robotic arm on Oct. 4, 2012. Japan Aerospace Exploration Agency astronaut Aki Hoshide, flight engineer, set up the satellite deployment gear inside the lab and placed it in the Kibo airlock. The Japanese robotic arm then grappled the deployment system and its satellites from the airlock for deployment.

NPP Satellite Launch

NASA Image and Video Library

2011-10-28

The Satellite Operations Facility of the National Oceanic and Atmospheric Administration (NOAA) is seen here minutes before the launch of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) on Friday, Oct. 28, 2011 in Suitland, Md. NPP is a joint venture between NASA and NOAA, and is the nation's newest Earth-observing satellite, which will provide data on climate change science, allow for accurate weather forecasts and advance warning for severe weather. NPP was launched from Vandenberg Air Force Base in California. Photo Credit: (NASA/Carla Cioffi)

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.

Echo 30" Sub Satellite

NASA Image and Video Library

2012-09-07

James Hansen describes the work on Project Echo s air density experiment known as the Sub-Satellite. Before launch engineers subjected the sub-satellite to many tests. Here, the sub-satellite is shown prior to tests to determine the capacity of the 30-inch Sub-Satellite to withstand the high temperature of direct sunlight in space, Langley researchers subjected it to 450 F heat test. Results indicated that the aluminum-covered Mylar plastic would effectively reflect the dangerous heat. -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308, p. 168.

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.

The Eccentric Satellites Problem: Comparing Milky Way Satellite Orbital Properties to Simulation Results

NASA Astrophysics Data System (ADS)

Haji, Umran; Pryor, Carlton; Applebaum, Elaad; Brooks, Alyson

2018-01-01

We compare the orbital properties of the satellite galaxies of the Milky Way to those of satellites found in simulated Milky Way-like systems as a means of testing cosmological simulations of galaxy formation. The particular problem that we are investigating is a discrepancy in the distribution of orbital eccentricities. Previous studies of Milky Way-mass systems analyzed in a semi-analytic ΛCDM cosmological model have found that the satellites tend to have significantly larger fractions of their kinetic energy invested in radial motion with respect to their central galaxy than do the real-world Milky Way satellites. We analyze several high-resolution ("zoom-in") hydrodynamical simulations of Milky Way-mass galaxies and their associated satellite systems to investigate why previous works found Milky Way-like systems to be rare. We find a possible relationship between a quiescent galactic assembly history and a distribution of satellite kinematics resembling that of the Milky Way. This project has been supported by funding from National Science Foundation grant PHY-1560077.

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

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.

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.

Land mobile satellite propagation measurements in Japan using ETS-V satellite

NASA Technical Reports Server (NTRS)

Obara, Noriaki; Tanaka, Kenji; Yamamoto, Shin-Ichi; Wakana, Hiromitsu

1993-01-01

Propagation characteristics of land mobile satellite communications channels have been investigated actively in recent years. Information of propagation characteristics associated with multipath fading and shadowing is required to design commercial land mobile satellite communications systems, including protocol and error correction method. CRL (Communications Research Laboratory) has carried out propagation measurements using the Engineering Test Satellite-V (ETS-V) at L band (1.5 GHz) through main roads in Japan by a medium gain antenna with an autotracking capability. This paper presents the propagation statistics obtained in this campaign.

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.

Stereoscopic observations from meteorological satellites

NASA Astrophysics Data System (ADS)

Hasler, A. F.; Mack, R.; Negri, A.

The capability of making stereoscopic observations of clouds from meteorological satellites is a new basic analysis tool with a broad spectrum of applications. Stereoscopic observations from satellites were first made using the early vidicon tube weather satellites (e.g., Ondrejka and Conover [1]). However, the only high quality meteorological stereoscopy from low orbit has been done from Apollo and Skylab, (e.g., Shenk et al. [2] and Black [3], [4]). Stereoscopy from geosynchronous satellites was proposed by Shenk [5] and Bristor and Pichel [6] in 1974 which allowed Minzner et al. [7] to demonstrate the first quantitative cloud height analysis. In 1978 Bryson [8] and desJardins [9] independently developed digital processing techniques to remap stereo images which made possible precision height measurement and spectacular display of stereograms (Hasler et al. [10], and Hasler [11]). In 1980 the Japanese Geosynchronous Satellite (GMS) and the U.S. GOES-West satellite were synchronized to obtain stereo over the central Pacific as described by Fujita and Dodge [12] and in this paper. Recently the authors have remapped images from a Low Earth Orbiter (LEO) to the coordinate system of a Geosynchronous Earth Orbiter (GEO) and obtained stereoscopic cloud height measurements which promise to have quality comparable to previous all GEO stereo. It has also been determined that the north-south imaging scan rate of some GEOs can be slowed or reversed. Therefore the feasibility of obtaining stereoscopic observations world wide from combinations of operational GEO and LEO satellites has been demonstrated. Stereoscopy from satellites has many advantages over infrared techniques for the observation of cloud structure because it depends only on basic geometric relationships. Digital remapping of GEO and LEO satellite images is imperative for precision stereo height measurement and high quality displays because of the curvature of the earth and the large angular separation of the

Saturn's outer satellite, Phoebe

NASA Technical Reports Server (NTRS)

1981-01-01

Voyager 2 took this photo of Saturn's outer satellite, Phoebe, on Sept. 4, 1981, from 2.2 million kilometers (1.36 million miles) away. The photo shows that Phoebe is about 200 kilometers (120 miles) in diameter, about twice the size of Earth-based measurements; and dark, with five percent reflectivity -- much darker than any other Saturnian satellite. That, and information from Earth-based observations, indicates Phoebe is almost certainly a captured asteroid, and did not form in the original Saturn nebula as Saturn's other satellites did. Phoebe is the only Saturnian satellite that does not always show the same face to Saturn: Its orbital period is 550 days. Its rotation period (length of day), determined from Voyager 2 observations, is nine to ten hours. Other ground-based observations that indicate that Phoebe is a captured asteroid: It orbits Saturn in the ecliptic plane (the plane in which Earth and most other planets orbit the Sun), rather than in Saturn's equatorial plane as the other Saturn satellites do. And Phoebe's orbit is retrograde -- in the direction opposite to that of the other satellites. Voyager is managed for NASA's Office of Space Science by the Jet Propulsion Laboratory.

Cost Consideration for Future Communications Satellite

NASA Astrophysics Data System (ADS)

Iida, Takashi

2002-01-01

This paper discusses the cost driving factors of the future communications satellite rather than discussing its cost itself directly, in terms of development period of time, services, and R&D by government. In the first, a period of time for development of a communications system is discussed in comparison of satellite communications system with a terrestrial communications system. Generally speaking, the terrestrial communications system is developed in a short period. Especially, the recent network related IT technology changes very rapidly, like so-called as "Dog Year". On the other hand, it takes a long time, more than several years, to develop a satellite communications system. This paper will discuss this time period of development is how to influence the system realization in various cases. In the second, the service related cost is discussed. First, a mobile communications satellite system is considered as an example. The tremendous penetration speed of the terrestrial cellular phones prevents from the success of the mobile satellite communications system. The success of the mobile satellite communications system depends on how early and user friendly to develop its user terminals. Second, the broadcasting service is described as a successful example. It is described that the satellite broadcasting has a very competitive advantage to the terrestrial broadcasting service from the cost point of view. Finally, the cost of the technology R&D for the future communication satellite by the government is discussed. A model of the future communications satellite for next 30 years has been proposed(1)(2). As an example, this paper estimates the satellite cost of the 60 Gbps range of capacity which is called as 1.5G satellite, where the capacity of the second generation Internet satellite (2G) is 50-500 Gbps per satellite. In the paper, the R&D plan of the future communications satellite will be discussed as a next R&D project to the first generation Internet

NPP Satellite Launch

NASA Image and Video Library

2011-10-28

NASA Deputy Administrator Lori Garver, left, watches the launch of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) at the National Oceanic and Atmospheric Administration (NOAA) Satellite Operations Center on Friday, Oct. 28, 2011 in Suitland, Md. U.S Congresswoman Donna Edwards, D-Md., is seen next to Garver. NPP is a joint venture between NASA and NOAA, and is the nation's newest Earth-observing satellite, which will provide data on climate change science, allow for accurate weather forecasts and advance warning for severe weather. NPP was launched from Vandenberg Air Force Base in California. Photo Credit: (NASA/Carla Cioffi)

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

NASA Technical Reports Server (NTRS)

Bartholomew, C. A.

1972-01-01

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

Spectrum and power allocation in cognitive multi-beam satellite communications with flexible satellite payloads

NASA Astrophysics Data System (ADS)

Liu, Zhihui; Wang, Haitao; Dong, Tao; Yin, Jie; Zhang, Tingting; Guo, Hui; Li, Dequan

2018-02-01

In this paper, the cognitive multi-beam satellite system, i.e., two satellite networks coexist through underlay spectrum sharing, is studied, and the power and spectrum allocation method is employed for interference control and throughput maximization. Specifically, the multi-beam satellite with flexible payload reuses the authorized spectrum of the primary satellite, adjusting its transmission band as well as power for each beam to limit its interference on the primary satellite below the prescribed threshold and maximize its own achievable rate. This power and spectrum allocation problem is formulated as a mixed nonconvex programming. For effective solving, we first introduce the concept of signal to leakage plus noise ratio (SLNR) to decouple multiple transmit power variables in the both objective and constraint, and then propose a heuristic algorithm to assign spectrum sub-bands. After that, a stepwise plus slice-wise algorithm is proposed to implement the discrete power allocation. Finally, simulation results show that adopting cognitive technology can improve spectrum efficiency of the satellite communication.

Interim Service ISDN Satellite (ISIS) hardware experiment development for advanced ISDN satellite designs and experiments

NASA Technical Reports Server (NTRS)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Service Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Development for Advanced Satellite Designs describes the development of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into Time Division Multiple Access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the RS-499 interface for satellite uplink. The same ISTA converts in the opposite direction the RS-499 to U-interface data with a simple switch setting.

Interim Service ISDN Satellite (ISIS) hardware experiment design for advanced ISDN satellite design and experiments

NASA Technical Reports Server (NTRS)

Pepin, Gerard R.

1992-01-01

The Interim Service Integrated Services Digital Network (ISDN) Satellite (ISIS) Hardware Experiment Design for Advanced Satellite Designs describes the design of the ISDN Satellite Terminal Adapter (ISTA) capable of translating ISDN protocol traffic into time division multiple access (TDMA) signals for use by a communications satellite. The ISTA connects the Type 1 Network Termination (NT1) via the U-interface on the line termination side of the CPE to the V.35 interface for satellite uplink. The same ISTA converts in the opposite direction the V.35 to U-interface data with a simple switch setting.

The Skeletal Muscle Satellite Cell

PubMed Central

2011-01-01

The skeletal muscle satellite cell was first described and named based on its anatomic location between the myofiber plasma and basement membranes. In 1961, two independent studies by Alexander Mauro and Bernard Katz provided the first electron microscopic descriptions of satellite cells in frog and rat muscles. These cells were soon detected in other vertebrates and acquired candidacy as the source of myogenic cells needed for myofiber growth and repair throughout life. Cultures of isolated myofibers and, subsequently, transplantation of single myofibers demonstrated that satellite cells were myogenic progenitors. More recently, satellite cells were redefined as myogenic stem cells given their ability to self-renew in addition to producing differentiated progeny. Identification of distinctively expressed molecular markers, in particular Pax7, has facilitated detection of satellite cells using light microscopy. Notwithstanding the remarkable progress made since the discovery of satellite cells, researchers have looked for alternative cells with myogenic capacity that can potentially be used for whole body cell-based therapy of skeletal muscle. Yet, new studies show that inducible ablation of satellite cells in adult muscle impairs myofiber regeneration. Thus, on the 50th anniversary since its discovery, the satellite cell’s indispensable role in muscle repair has been reaffirmed. PMID:22147605

Communication Technology Satellite Portable Terminal

NASA Image and Video Library

1977-03-21

This vehicle served as a mobile terminal for the Communications Technology Satellite. The Communications Technology Satellite was an experimental communications satellite launched in January 1976 by the National Aeronautics and Space Administration (NASA) and the Canadian Department of Communications. The satellite operated in a new frequency band reserved for broadcast satellites with transmitting power levels that were 10 to 20 times higher than those of contemporary satellites. Throughout 1977 and 1978 NASA allowed qualified groups to utilize the satellite from one of the three ground-based transmission centers. NASA’s Lewis Research Center in Cleveland, Ohio was NASA’s lead center on the project. Lewis was responsible for the control and coordination of all US experiments on the satellite. The center housed the satellite’s main control center which included eight parabolic reflector antennae ranging from 2 to 15 feet in diameter. Many of the satellite’s components had been tested in simulated space conditions at Lewis. The Lewis-designed vehicle seen here served as a field unit for transmitting and receiving wideband signals and narrowband voice. The vehicle permitted live television interviews, recording equipment, and cameras. An 8-foot diameter parabolic reflector was mounted on the roof. The interior of the vehicle had workstations, monitors, transmitting equipment, and a lounge area.

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.

JEMRMS Small Satellite Deployment Observation

NASA Image and Video Library

2012-10-04

ISS033-E-009315 (4 Oct. 2012) --- Several tiny satellites are featured in this image photographed by an Expedition 33 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module’s robotic arm on Oct. 4, 2012. Japan Aerospace Exploration Agency astronaut Aki Hoshide, flight engineer, set up the satellite deployment gear inside the lab and placed it in the Kibo airlock. The Japanese robotic arm then grappled the deployment system and its satellites from the airlock for deployment. A blue and white part of Earth provides the backdrop for the scene.

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.

Collision Avoidance: Coordination of Predicted Conjunctions between NASA Satellites and Satellites of other Countries

NASA Astrophysics Data System (ADS)

Kelly, A.; Watson, W.

2014-09-01

This paper describes one of the challenges facing the flight operations teams of the International Earth Observing constellation satellites at the 705 km orbit, including NASAs satellites. The NASA Earth Science Mission Operations (ESMO) Project has been dealing with predicted conjunctions (close approach) between operational/non-operational space objects and the satellites in the International Earth observing constellations for several years. Constellation satellites include: NASAs Earth Observing System (EOS) Terra, Aqua, and Aura, CloudSat, the joint NASA/CNES CALIPSO mission, Earth Observing 1 (EO-1), the Japan Aerospace and Exploration Agency (JAXA) Global Change Observation Mission-Water 1 (GCOM-W1) mission, the United States Geological Survey (USGS) Landsat 7 and Landsat 8, and until 2013, Argentinas SAC-C mission and the CNES PARASOL mission. The NASA Conjunction Analysis and Risk Assessment (CARA) team provides daily reports to the ESMO Project regarding any high interest close approach events (HIEs) involving the constellation satellites. The daily CARA reports provide risk assessment results that help the operations teams to determine if there is a need to perform a risk mitigation action. If the conjuncting space object is an operational satellite that is capable of maneuvering, the affected satellite team needs to coordinate their action plan with the owner operator of the conjuncting satellite. It is absolutely critical for the two teams to communicate as soon as possible. The goal is to minimize the collision risk; this can happen if both satellite operators do not coordinate their maneuver plans. The constellation teams have established guidelines for coordinating HIEs. This coordination process has worked successfully for several years for satellites that are operated by other organizations in the United States and by NASAs international partners, all with whom NASA has a cooperative agreement. However, the situation is different for HIEs with

Small Satellite Propulsion Options

NASA Technical Reports Server (NTRS)

Myers, Roger M.; Oleson, Steven R.; Curran, Francis M.; Schneider, Steven J.

1994-01-01

Advanced chemical and low power electric propulsion offer attractive options for small satellite propulsion. Applications include orbit raising, orbit maintenance, attitude control, repositioning, and deorbit of both Earth-space and planetary spacecraft. Potential propulsion technologies for these functions include high pressure Ir/Re bipropellant engines, very low power arcjets, Hall thrusters, and pulsed plasma thrusters, all of which have been shown to operate in manners consistent with currently planned small satellites. Mission analyses show that insertion of advanced propulsion technologies enables and/or greatly enhances many planned small satellite missions. Examples of commercial, DoD, and NASA missions are provided to illustrate the potential benefits of using advanced propulsion options on small satellites.

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.’

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.

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.

Broadcast satellite service: The international dimension

NASA Technical Reports Server (NTRS)

Samara, Noah

1991-01-01

The dawn of the 1990's has witnessed the birth of a new satellite service - satellite sound broadcasting. This new service is characterized by digital transmission at data rates up to 256 kb/s from satellites in geostationary orbit to small, low-cost, mobile and portable receivers. The satellite sound broadcasting service is a logical step beyond navigation satellite service, such as that provided by the GPS Navstar system. The mass market appeal of satellite sound broadcasting in the area of lightsat technology and low-cost digital radios has greatly facilitated the financing of this type of space service.

Broadcast satellite service: The international dimension

NASA Astrophysics Data System (ADS)

Samara, Noah

1991-09-01

The dawn of the 1990's has witnessed the birth of a new satellite service - satellite sound broadcasting. This new service is characterized by digital transmission at data rates up to 256 kb/s from satellites in geostationary orbit to small, low-cost, mobile and portable receivers. The satellite sound broadcasting service is a logical step beyond navigation satellite service, such as that provided by the GPS Navstar system. The mass market appeal of satellite sound broadcasting in the area of lightsat technology and low-cost digital radios has greatly facilitated the financing of this type of space service.

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.

Satellite applications to electric-utility communications needs. [land mobile satellite service

NASA Technical Reports Server (NTRS)

Horstein, M.; Barnett, R.

1981-01-01

Significant changes in the Nation's electric power systems are expected to result from the integration of new technology, possible during the next decade. Digital communications for monitor and control, exclusive of protective relaying, are expected to double or triple current traffic. A nationwide estimate of 13 Mb/s traffic is projected. Of this total, 8 Mb/s is attributed to the bulk-power system as it is now being operated (4 Mb/s). This traffic could be accommodated by current communications satellites using 3- to 4.5-m-diameter ground terminals costing $35,000 to $70,000 each. The remaining 5-Mb/s traffic is attributed to new technology concepts integrated into the distribution system. Such traffic is not compatible with current satellite technology because it requires small, low-cost ground terminals. Therefore, a high effective isotropic radiated power satellite, such as the one being planned by NASA for the Land Mobile Satellite Service, is required.

NPP Satellite Launch

NASA Image and Video Library

2011-10-28

Dr. Kathy Sullivan, center, Deputy Administrator of the National Oceanic and Atmospheric Administration (NOAA) and former NASA astronaut is interviewed by a local television network at NOAA's Satellite Operations Facility in Suitland, Md. after the successful launch of the National Polar-orbiting Operational Environmental Satellite System Preparatory Project (NPP) on Friday, Oct. 28, 2011. NPP is a joint venture between NASA and NOAA, and is the nation's newest Earth-observing satellite, which will provide data on climate change science, allow for accurate weather forecasts and advance warning for severe weather. NPP was launched from Vandenberg Air Force Base in California. Photo Credit: (NASA/Carla Cioffi)

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).

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)

JPSS Preparations at the Satellite Proving Ground for Marine, Precipitation, and Satellite Analysis

NASA Astrophysics Data System (ADS)

Folmer, M. J.; Berndt, E.; Clark, J.; Orrison, A.; Kibler, J.; Sienkiewicz, J. M.; Nelson, J. A., Jr.; Goldberg, M.

2016-12-01

The National Oceanic and Atmospheric Administration (NOAA) Satellite Proving Ground (PG) for Marine, Precipitation, and Satellite Analysis (MPS) has been demonstrating and evaluating Suomi National Polar-orbiting Partnership (S-NPP) products along with other polar-orbiting satellite platforms in preparation for the Joint Polar Satellite System - 1 (JPSS-1) launch in March 2017. The first S-NPP imagery was made available to the MPS PG during the evolution of Hurricane Sandy in October 2012 and has since been popular in operations. Since this event the MPS PG Satellite Liaison has been working with forecasters on ways to integrate single-channel and multispectral imagery from the Visible Infrared Imaging Radiometer Suite (VIIRS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and the Advanced Very High Resolution Radiometer (AVHRR)into operations to complement numerical weather prediction and geostationary satellite savvy National Weather Service (NWS) National Centers. Additional unique products have been introduced to operations to address specific forecast challenges, including the Cooperative Institute for Research in the Atmosphere (CIRA) Layered Precipitable Water, the National Environmental Satellite, Data, and Information Service (NESDIS) Snowfall Rate product, NOAA Unique Combined Atmospheric Processing System (NUCAPS) Soundings, ozone products from the Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder/Advanced Technology Microwave Sounder (CrIS/ATMS), and Infrared Atmospheric Sounding Interferometer (IASI). In addition, new satellite domains have been created to provide forecasters at the NWS Ocean Prediction Center and Weather Prediction Center with better quality imagery at high latitudes. This has led to research projects that are addressing forecast challenges such as tropical to extratropical transition and explosive cyclogenesis. This presentation will provide examples of how the MPS PG has been introducing and integrating

Impact of multiconstellation satellite signal reception on performance of satellite-based navigation under adverse ionospheric conditions

NASA Astrophysics Data System (ADS)

Paul, Ashik; Paul, Krishnendu Sekhar; Das, Aditi

2017-03-01

Application of multiconstellation satellites to address the issue of satellite signal outages during periods of equatorial ionospheric scintillations could prove to be an effective tool for maintaining the performance of satellite-based communication and navigation without compromise in accuracy and integrity. A receiver capable of tracking GPS, Global Navigation Satellite System (GLONASS), and Galileo satellites is operational at the Institute of Radio Physics and Electronics, University of Calcutta, Calcutta, India, located near the northern crest of the equatorial ionization anomaly in the Indian longitude sector. The present paper shows increased availability of satellites combining GPS, GLONASS, and Galileo constellations from Calcutta compared to GPS-only scenario and estimates intense scintillation-free (S4 < 0.6) satellite vehicle look angles at different hours of the postsunset period 19:00-01:00 LT during March 2014. A representative case of 1 March 2014 is highlighted in the paper and overall statistics for March 2014 presented to indicate quantitative advantages in terms of scintillation-free satellite vehicle look angles that may be utilized for planning communication and navigation channel spatial distribution under adverse ionospheric conditions. The number of satellites tracked and receiver position deviations has been found to show a good correspondence with the occurrence of intense scintillations and poor user receiver-satellite link geometry. The ground projection of the 350 km subionospheric points corresponding to multiconstellation shows extended spatial coverage during periods of scintillations (0.2 < S4 < 0.6) compared to GPS.

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.

Leveraging the NPS Femto Satellite for Alternative Satellite Communication Networks

DTIC Science & Technology

2017-09-01

the next-generation NPSFS. 14. SUBJECT TERMS space , Femto satellite, NPSFS, network, communication , Arduino, RockBlock, Iridium Modem 15. NUMBER...provides a proof of concept for using Naval Postgraduate School Femto Satellites (NPSFS) as an alternative communication space -based network. The...We need several physical and procedural elements to conduct communication through space and using the electromagnetic spectrum. 1. Power Any

Design Considerations for a Dedicated Gravity Recovery Satellite Mission Consisting of Two Pairs of Satellites

NASA Technical Reports Server (NTRS)

Wiese, D. N.; Nerem, R. S.; Lemoine, F. G.

2011-01-01

Future satellite missions dedicated to measuring time-variable gravity will need to address the concern of temporal aliasing errors; i.e., errors due to high-frequency mass variations. These errors have been shown to be a limiting error source for future missions with improved sensors. One method of reducing them is to fly multiple satellite pairs, thus increasing the sampling frequency of the mission. While one could imagine a system architecture consisting of dozens of satellite pairs, this paper explores the more economically feasible option of optimizing the orbits of two pairs of satellites. While the search space for this problem is infinite by nature, steps have been made to reduce it via proper assumptions regarding some parameters and a large number of numerical simulations exploring appropriate ranges for other parameters. A search space originally consisting of 15 variables is reduced to two variables with the utmost impact on mission performance: the repeat period of both pairs of satellites (shown to be near-optimal when they are equal to each other), as well as the inclination of one of the satellite pairs (the other pair is assumed to be in a polar orbit). To arrive at this conclusion, we assume circular orbits, repeat groundtracks for both pairs of satellites, a 100-km inter-satellite separation distance, and a minimum allowable operational satellite altitude of 290 km based on a projected 10-year mission lifetime. Given the scientific objectives of determining time-variable hydrology, ice mass variations, and ocean bottom pressure signals with higher spatial resolution, we find that an optimal architecture consists of a polar pair of satellites coupled with a pair inclined at 72deg, both in 13-day repeating orbits. This architecture provides a 67% reduction in error over one pair of satellites, in addition to reducing the longitudinal striping to such a level that minimal post-processing is required, permitting a substantial increase in the spatial

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…

DS-CDMA satellite diversity reception for personal satellite communication: Downlink performance analysis

NASA Technical Reports Server (NTRS)

DeGaudenzi, Riccardo; Giannetti, Filippo

1995-01-01

The downlink of a satellite-mobile personal communication system employing power-controlled Direct Sequence Code Division Multiple Access (DS-CDMA) and exploiting satellite-diversity is analyzed and its performance compared with a more traditional communication system utilizing single satellite reception. The analytical model developed has been thoroughly validated by means of extensive Monte Carlo computer simulations. It is shown how the capacity gain provided by diversity reception shrinks considerably in the presence of increasing traffic or in the case of light shadowing conditions. Moreover, the quantitative results tend to indicate that to combat system capacity reduction due to intra-system interference, no more than two satellites shall be active over the same region. To achieve higher system capacity, differently from terrestrial cellular systems, Multi-User Detection (MUD) techniques are likely to be required in the mobile user terminal, thus considerably increasing its complexity.

Local gravity disturbance estimation from multiple-high-single-low satellite-to-satellite tracking

NASA Technical Reports Server (NTRS)

Jekeli, Christopher

1989-01-01

The idea of satellite-to-satellite tracking in the high-low mode has received renewed attention in light of the uncertain future of NASA's proposed low-low mission, Geopotential Research Mission (GRM). The principal disadvantage with a high-low system is the increased time interval required to obtain global coverage since the intersatellite visibility is often obscured by Earth. The U.S. Air Force has begun to investigate high-low satellite-to-satellite tracking between the Global Positioning System (GPS) of satellites (high component) and NASA's Space Transportation System (STS), the shuttle (low component). Because the GPS satellites form, or will form, a constellation enabling continuous three-dimensional tracking of a low-altitude orbiter, there will be no data gaps due to lack of intervisibility. Furthermore, all three components of the gravitation vector are estimable at altitude, a given grid of which gives a stronger estimate of gravity on Earth's surface than a similar grid of line-of-sight gravitation components. The proposed Air Force mission is STAGE (Shuttle-GPS Tracking for Anomalous Gravitation Estimation) and is designed for local gravity field determinations since the shuttle will likely not achieve polar orbits. The motivation for STAGE was the feasibility to obtain reasonable accuracies with absolutely minimal cost. Instead of simulating drag-free orbits, STAGE uses direct measurements of the nongravitational forces obtained by an inertial package onboard the shuttle. The sort of accuracies that would be achievable from STAGE vis-a-vis other satellite tracking missions such as GRM and European Space Agency's POPSAT-GRM are analyzed.

Encryption protection for communication satellites

NASA Astrophysics Data System (ADS)

Sood, D. R.; Hoernig, O. W., Jr.

In connection with the growing importance of the commercial communication satellite systems and the introduction of new technological developments, users and operators of these systems become increasingly concerned with aspects of security. The user community is concerned with maintaining confidentiality and integrity of the information being transmitted over the satellite links, while the satellite operators are concerned about the safety of their assets in space. In response to these concerns, the commercial satellite operators are now taking steps to protect the communication information and the satellites. Thus, communication information is being protected by end-to-end encryption of the customer communication traffic. Attention is given to the selection of the NBS DES algorithm, the command protection systems, and the communication protection systems.

Satellite Communications Industry

DTIC Science & Technology

1993-04-01

Ariane $loom SAJAC 1 Hughes Satellite Japan 06/94 $150m SAJAC 2 Hughes Satellite Japan -- (spare) $150m SatcomHl GE GE Americom /95 $50m SOLIDARIDAD ...1 Hughes SCT (Mexico) 11/93 Ariane $loom SOLIDARIDAD 2 Hughes SCT (Mexico) /94 $loom Superbird Al Loral Space Com Gp (Jap) 11/92 Ariane $175m

Satellite power system operations

NASA Technical Reports Server (NTRS)

Pugh, F. L.; Gordon, A. I.

1980-01-01

A projection of the electrical energy demands over the next 30 to 50 years, coupled with reasonable assessments of known or developable energy sources, indicates that a shortage of electrical energy will occur about the turn of the century. Recognizing the criticality of such a shortage, the Department of Energy is currently evaluating alternative power generation concepts. One of these candidate concepts is the Satellite Power System. The power levels considered during the evaluation of the various satellite systems have ranged from 5 to 10 GW. It is apparent that, with this power level, both the satellite and the rectenna must be very large and encompass a large number of complex operational system activities. Major elements of the Satellite Power System (SPS) consist of a power satellite placed in a geosynchronous equatorial orbit, and a dedicated ground receiving station (GRS) located at a selected site within the continental United States. The nominal power output of the SPS is established at 5 gigawatts (5 million kilowatts) although, because of various system constraints or losses, it may actually produce between 4 and 5 gigawatts.

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.

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.

Ocean surveillance satellites

NASA Astrophysics Data System (ADS)

Laurent, D.

Soviet and U.S. programs involving satellites for surveillance of ships and submarines are discussed, considering differences in approaches. The Soviet program began with the Cosmos 198 in 1967 and the latest, the Cosmos 1400 series, 15 m long and weighing 5 tons, carry radar for monitoring ships and a nuclear reactor for a power supply. Other Soviet spacecraft carrying passive microwave sensors and ion drives powered by solar panels have recently been detonated in orbit for unknown reasons. It has also been observed that the Soviet satellites are controlled in pairs, with sequential orbital changes for one following the other, and both satellites then overflying the same points. In contrast, U.S. surveillance satellites have been placed in higher orbits, thus placing greater demands on the capabilities of the on-board radar and camera systems. Project White Cloud and the Clipper Bow program are described, noting the continued operation of the White Cloud spacecraft, which are equipped to intercept radio signals from surface ships. Currently, the integrated tactical surveillance system program has completed its study and a decision is expected soon.

Quarantine constraints as applied to satellites.

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Stavro, W.; Gonzalez, C.

1973-01-01

Plans for unmanned missions to planets beyond Mars in the 1970s include satellite encounters. Recently published observations of data for Titan, a satellite of Saturn, indicate that conditions may be hospitable for the growth of microorganisms. Therefore, the problem of satisfying possible quarantine constraints for outer planet satellites was investigated. This involved determining the probability of impacting a satellite of Jupiter or Saturn by a spacecraft for a planned satellite encounter during an outer planet mission. Mathematical procedures were formulated which (1) determine the areas in the aim-plane that would result in trajectories that impact the satellite and (2) provide a technique for numerically integrating the navigation error function over the impact area to obtain impact probabilities. The results indicate which of the planned spacecraft trajectory correction maneuvers are most critical in terms of satellite quarantine violation.

Quarantine constraints as applied to satellites

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Stavro, W.; Gonzalez, C. C.

1973-01-01

Plans for unmanned missions to planets beyond Mars in the 1970s include satellite encounters. Recently published observations of data for Titan, a satellite of Saturn, indicate that conditions may be hospitable for the growth of microorganisms. Therefore, the problem of satisfying possible quarantine constraints for outer planet satellites was investigated. This involved determining the probability of impacting a satellite of Jupiter or Saturn by a spacecraft for a planned satellite encounter during an outer planet mission. Mathematical procedures were formulated which determine the areas in the aim-plane that would result in trajectories that impact the satellite and provide a technique for numerically integrating the navigation error function over the impact area to obtain impact probabilities. The results indicate which of the planned spacecraft trajectory correction maneuvers are most critical in terms of satellite quarantine violation.

On-Orbit Calibration of a Multi-Spectral Satellite Satellite Sensor Using a High Altitude Airborne Imaging Spectrometer

NASA Technical Reports Server (NTRS)

Green, R. O.; Shimada, M.

1996-01-01

Earth-looking satellites must be calibrated in order to quantitatively measure and monitor components of land, water and atmosphere of the Earth system. The inevitable change in performance due to the stress of satellite launch requires that the calibration of a satellite sensor be established and validated on-orbit. A new approach to on-orbit satellite sensor calibration has been developed using the flight of a high altitude calibrated airborne imaging spectrometer below a multi-spectral satellite sensor.

Muscle satellite cell heterogeneity and self-renewal

PubMed Central

Motohashi, Norio; Asakura, Atsushi

2014-01-01

Adult skeletal muscle possesses extraordinary regeneration capacities. After muscle injury or exercise, large numbers of newly formed muscle fibers are generated within a week as a result of expansion and differentiation of a self-renewing pool of muscle stem cells termed muscle satellite cells. Normally, satellite cells are mitotically quiescent and reside beneath the basal lamina of muscle fibers. Upon regeneration, satellite cells are activated, and give rise to daughter myogenic precursor cells. After several rounds of proliferation, these myogenic precursor cells contribute to the formation of new muscle fibers. During cell division, a minor population of myogenic precursor cells returns to quiescent satellite cells as a self-renewal process. Currently, accumulating evidence has revealed the essential roles of satellite cells in muscle regeneration and the regulatory mechanisms, while it still remains to be elucidated how satellite cell self-renewal is molecularly regulated and how satellite cells are important in aging and diseased muscle. The number of satellite cells is decreased due to the changing niche during ageing, resulting in attenuation of muscle regeneration capacity. Additionally, in Duchenne muscular dystrophy (DMD) patients, the loss of satellite cell regenerative capacity and decreased satellite cell number due to continuous needs for satellite cells lead to progressive muscle weakness with chronic degeneration. Thus, it is necessary to replenish muscle satellite cells continuously. This review outlines recent findings regarding satellite cell heterogeneity, asymmetric division and molecular mechanisms in satellite cell self-renewal which is crucial for maintenance of satellite cells as a muscle stem cell pool throughout life. In addition, we discuss roles in the stem cell niche for satellite cell maintenance, as well as related cell therapies for approaching treatment of DMD. PMID:25364710

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.

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…

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.

Earth Observation Satellites and Chinese Applications

NASA Astrophysics Data System (ADS)

Li, D.

In this talk existing and future Earth observation satellites are briefly described These satellites include meteorological satellites ocean satellites land resources satellites cartographic satellites and gravimetric satellites The Chinese government has paid and will pay more attention to and put more effort into enhancing Chinese earth observation satellite programs in the next fifteen years The utilization of these satellites will effectively help human beings to solve problems it faces in areas such as population natural resources and environment and natural hazards The author will emphasize the originality of the scientific and application aspects of the Chinese program in the field of Earth observations The main applications include early warning and prevention of forest fires flooding and drought disaster water and ocean ice disasters monitoring of landslides and urban subsidence investigation of land cover change and urban expansion as well as urban and rural planning The author introduces the most up-to-date technology used by Chinese scientists including fusion and integration of multi-sensor multi-platform optical and SAR data of remote sensing Most applications in China have obtained much support from related international organizations and universities around the world These applications in China are helpful for economic construction and the efficient improvement of living quality

University Satellite Consortium and Space Education in Japan Centered on Micro-Nano Satellites

NASA Astrophysics Data System (ADS)

Nakasuka, S.; Kawashima, R.

2002-01-01

in Japan especially centered on micro or nano class satellites. Hands-on training using micro-nano satellites provide unique opportunity of space education to university level students, by giving them a chance to experience the whole space project cycle from mission creation, satellite design, fabrication, test, launch, operation through analysis of the results. Project management and team working are other important skills that can be trained in these projects. include 1) low cost, which allows one laboratory in university to carry out a project, 2) short development period such as one or two year, which enables students to obtain the results of their projects before they graduate, and 3) small size and weight, which enables fabrication and test within usually very narrow university laboratory areas. In Japan, several projects such as CanSat, CubeSat or Whale Observation Satellite have been carried out, proving that micro-nano satellites provide very unique and valuable educational opportunity. with the objective to make a university student and staff community of these micro-nano satellite related activities in Japan. This consortium aims for many activities including facilitating information and skills exchange and collaborations between member universities, helping students to use ground test facilities of national laboratories, consulting them on political or law related matters, coordinating joint development of equipments or projects, and bridging between these university activities and the needs or interests of the people in general. This kind of outreach activity is essential because how to create missions of micro-nano satellites should be pursued in order for this field to grow larger than a merely educational enterprise. The final objectives of the consortium is to make a huge community of the users, mission creators, investors and manufactures(i.e., university students) of micro-nano satellites, and provide a unique contribution to the activation of

Direct Broadcast Satellite: Radio Program

NASA Astrophysics Data System (ADS)

Hollansworth, James E.

1992-10-01

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.

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.

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.

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.

Design and Fabrication of DebriSat - A Representative LEO Satellite for Improvements to Standard Satellite Breakup Models

NASA Technical Reports Server (NTRS)

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

2012-01-01

This paper discusses the design and fabrication of DebriSat, a 50 kg satellite developed to be representative of a modern low Earth orbit satellite in terms of its components, materials used, and fabrication procedures. DebriSat will be the target of a future hypervelocity impact experiment to determine the physical characteristics of debris generated after an on-orbit collision of a modern LEO satellite. The major ground-based satellite impact experiment used by DoD and NASA in their development of satellite breakup models was SOCIT, conducted in 1992. The target used for that experiment was a Navy transit satellite (40 cm, 35 kg) fabricated in the 1960's. Modern satellites are very different in materials and construction techniques than those built 40 years ago. Therefore, there is a need to conduct a similar experiment using a modern target satellite to improve the fidelity of the satellite breakup models. To ensure that DebriSat is truly representative of typical LEO missions, a comprehensive study of historical LEO satellite designs and missions within the past 15 years for satellites ranging from 1 kg to 5000 kg was conducted. This study identified modern trends in hardware, material, and construction practices utilized in recent LEO missions. Although DebriSat is an engineering model, specific attention is placed on the quality, type, and quantity of the materials used in its fabrication to ensure the integrity of the outcome. With the exception of software, all other aspects of the satellite s design, fabrication, and assembly integration and testing will be as rigorous as that of an actual flight vehicle. For example, to simulate survivability of launch loads, DebriSat will be subjected to a vibration test. As well, the satellite will undergo thermal vacuum tests to verify that the components and overall systems meet typical environmental standards. Proper assembly and integration techniques will involve comprehensive joint analysis, including the precise

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.

Satellite antenna management system and method

NASA Technical Reports Server (NTRS)

Leath, Timothy T (Inventor); Azzolini, John D (Inventor)

1999-01-01

The antenna management system and method allow a satellite to communicate with a ground station either directly or by an intermediary of a second satellite, thus permitting communication even when the satellite is not within range of the ground station. The system and method employ five major software components, which are the control and initialization module, the command and telemetry handler module, the contact schedule processor module, the contact state machining module, and the telemetry state machine module. The control and initialization module initializes the system and operates the main control cycle, in which the other modules are called. The command and telemetry handler module handles communication to and from the ground station. The contact scheduler processor module handles the contact entry schedules to allow scheduling of contacts with the second satellite. The contact and telemetry state machine modules handle the various states of the satellite in beginning, maintaining and ending contact with the second satellite and in beginning, maintaining and ending communication with the satellite.

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.

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.

Normalization and calibration of geostationary satellite radiances for the International Satellite Cloud Climatology Project

NASA Technical Reports Server (NTRS)

Desormeaux, Yves; Rossow, William B.; Brest, Christopher L.; Campbell, G. G.

1993-01-01

Procedures are described for normalizing the radiometric calibration of image radiances obtained from geostationary weather satellites that contributed data to the International Satellite Cloud Climatology Project. The key step is comparison of coincident and collocated measurements made by each satellite and the concurrent AVHRR on the 'afternoon' NOAA polar-orbiting weather satellite at the same viewing geometry. The results of this comparison allow transfer of the AVHRR absolute calibration, which has been established over the whole series, to the radiometers on the geostationary satellites. Results are given for Meteosat-2, 3, and 4, for GOES-5, 6, and 7, for GMS-2, 3, and 4 and for Insat-1B. The relative stability of the calibrations of these radiance data is estimated to be within +/- 3 percent; the uncertainty of the absolute calibrations is estimated to be less than 10 percent. The remaining uncertainties are at least two times smaller than for the original radiance data.

Satellite Cell Self-Renewal.

PubMed

Giordani, Lorenzo; Parisi, Alice; Le Grand, Fabien

2018-01-01

Adult skeletal muscle is endowed with regenerative potential through partially recapitulating the embryonic developmental program. Upon acute injury or in pathological conditions, quiescent muscle-resident stem cells, called satellite cells, become activated and give rise to myogenic progenitors that massively proliferate, differentiate, and fuse to form new myofibers and restore tissue functionality. In addition, a proportion of activated cells returns back to quiescence and replenish the pool of satellite cells in order to maintain the ability of skeletal muscle tissue to repair. Self-renewal is the process by which stem cells divide to make more stem cells to maintain the stem cell population throughout life. This process is controlled by cell-intrinsic transcription factors regulated by cell-extrinsic signals from the niche and the microenvironment. This chapter provides an overview about the general aspects of satellite cell biology and focuses on the cellular and molecular aspects of satellite cell self-renewal. To date, we are still far from understanding how a very small proportion of the satellite cell progeny maintain their stem cell identity when most of their siblings progress through the myogenic program to construct myofibers. © 2018 Elsevier Inc. All rights reserved.

Meteorological Satellite Education Resources: Web-based Learning Modules, Initiatives, and the Environmental Satellite Resource Center (ESRC)

NASA Astrophysics Data System (ADS)

Schreiber-Abshire, W.; Dills, P.

2008-12-01

The COMET® Program (www.comet.ucar.edu) receives funding from NOAA NESDIS and the NPOESS Integrated Program Office (IPO), with additional contributions from the GOES-R Program Office and EUMETSAT, to directly support education and training efforts in the area of satellite meteorology. This partnership enables COMET to create educational materials of global interest on geostationary and polar- orbiting remote sensing platforms and their instruments, data, products, and operational applications. Over the last several years, COMET's satellite education programs have focused on the capabilities and applications of the upcoming next generation operational polar-orbiting NPP/NPOESS system and its relevance to operational forecasters and other user communities. COMET's activities have recently expanded to include education on the future Geostationary Operational Environmental Satellites (GOES-R). By partnering with experts from the Naval Research Laboratory, NOAA-NESDIS and various user communities, COMET stimulates greater utilization of both current and future satellite observations and products. In addition, COMET has broadened the scope of its online training to include materials on the EUMETSAT Polar-orbiting System (EPS) and Meteosat geostationary satellites. EPS represents an important contribution to the Initial Joint Polar System (IJPS) between NOAA and EUMETSAT, while Meteosat imaging capabilities provide an early look for the next generation GOES-R satellites. Also in collaboration with EUMETSAT, COMET is developing future modules on the joint NASA-CNES Jason altimetry mission and on satellite capabilities for monitoring the global climate. COMET also provides Spanish translations of relevant GOES materials in order to support the GEOSS (Global Earth Observation System of Systems) Americas effort, which is associated with the move of GOES-10 to provide routine satellite coverage over South America. This poster presentation provides an overview of COMET

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.

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…

Donor Satellite Cell Engraftment is Significantly Augmented When the Host Niche is Preserved and Endogenous Satellite Cells are Incapacitated

PubMed Central

Boldrin, Luisa; Neal, Alice; Zammit, Peter S; Muntoni, Francesco; Morgan, Jennifer E

2012-01-01

Stem cell transplantation is already in clinical practice for certain genetic diseases and is a promising therapy for dystrophic muscle. We used the mdx mouse model of Duchenne muscular dystrophy to investigate the effect of the host satellite cell niche on the contribution of donor muscle stem cells (satellite cells) to muscle regeneration. We found that incapacitation of the host satellite cells and preservation of the muscle niche promote donor satellite cell contribution to muscle regeneration and functional reconstitution of the satellite cell compartment. But, if the host niche is not promptly refilled, or is filled by competent host satellite cells, it becomes nonfunctional and donor engraftment is negligible. Application of this regimen to aged host muscles also promotes efficient regeneration from aged donor satellite cells. In contrast, if the niche is destroyed, yet host satellite cells remain proliferation-competent, donor-derived engraftment is trivial. Thus preservation of the satellite cell niche, concomitant with functional impairment of the majority of satellite cells within dystrophic human muscles, may improve the efficiency of stem cell therapy. Stem Cells2012;30:1971–1984 PMID:22730231

Joint Polar Satellite System

NASA Technical Reports Server (NTRS)

Trenkle, Timothy; Driggers, Phillip

2011-01-01

The Joint Polar Satellite System (JPSS) is a joint NOAA/NASA mission comprised of a series of polar orbiting weather and climate monitoring satellites which will fly in a sun-synchronous orbit, with a 1330 equatorial crossing time. JPSS resulted from the decision to reconstitute the National Polar-orbiting Operational Environmental Satellite System (NPOESS) into two separate programs, one to be run by the Department of Defense (DOD) and the other by NOAA. This decision was reached in early 2010, after numerous development issues caused a series of unacceptable delays in launching the NPOESS system.

Probability of satellite collision

NASA Technical Reports Server (NTRS)

Mccarter, J. W.

1972-01-01

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

Satellite-Based EMI Detection, Identification, and Mitigation

NASA Astrophysics Data System (ADS)

Stottler, R.; Bowman, C.

2016-09-01

Commanding, controlling, and maintaining the health of satellites requires a clear operating spectrum for communications. Electro Magnetic Interference (EMI) from other satellites can interfere with these communications. Determining which satellite is at fault improves space situational awareness and can be used to avoid the problem in the future. The Rfi detection And Prediction Tool, Optimizing Resources (RAPTOR) monitors the satellite communication antenna signals to detect EMI (also called RFI for Radio Frequency Interference) using a neural network trained on past cases of both normal communications and EMI events. RAPTOR maintains a database of satellites that have violated the reserved spectrum in the past. When satellite-based EMI is detected, RAPTOR first checks this list to determine if any are angularly close to the satellite being communicated with. Additionally, RAPTOR checks the Space Catalog to see if any of its active satellites are angularly close. RAPTOR also consults on-line databases to determine if the described operating frequencies of the satellites match the detected EMI and recommends candidates to be added to the known offenders database, accordingly. Based on detected EMI and predicted orbits and frequencies, RAPTOR automatically reschedules satellite communications to avoid current and future satellite-based EMI. It also includes an intuitive display for a global network of satellite communications antennas and their statuses including the status of their EM spectrum. RAPTOR has been prototyped and tested with real data (amplitudes versus frequency over time) for both satellite communication signals and is currently undergoing full-scale development. This paper describes the RAPTOR technologies and results of testing.

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'.

Rotational properties of planetary satellites

NASA Technical Reports Server (NTRS)

Peale, S. J.

1991-01-01

Properties of satellite rotation that are observable in principle, include the rotation period, the orientation of the spin axis relative to the orbit plane, precession of the spin axis due to gravitational torques, nonprincipal axis rotation or wobble, and deviations from uniform principle axis rotation or libration. Considerable order is observed in current satellite rotation states, and it is of interest to ascertain how this order came about and why some satellites do not conform to the dominant norm. There is a strong coupling between the spin and orbital motions that is primarily responsible for maintaining the ordered rotation states in most cases, but this coupling is equally responsible for destroying any chance of orderly rotation for Saturn's satellite Hyperion. Understanding the processes which constrain current rotation states as well as those of an evolutionary nature which could have brought the individual satellites to their observed rotation and orbit states allows us to sometimes infer interior properties of some satellite or even of its primary planet, although, attempts to deduce primordial rotation states are usually frustrated. The observed rotational properties of the planetary satellites are summarized, and the understanding of the processes maintaining and those leading to the observed states are outlined. Some of the inferences that can be drawn about intrinsic properties of the bodies themselves are indicated.

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

History of on-orbit satellite fragmentations

NASA Astrophysics Data System (ADS)

Nauer, David J.

1992-07-01

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

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.

Communication Satellite Payload Special Check out Equipment (SCOE) for Satellite Testing

NASA Astrophysics Data System (ADS)

Subhani, Noman

2016-07-01

This paper presents Payload Special Check out Equipment (SCOE) for the test and measurement of communication satellite Payload at subsystem and system level. The main emphasis of this paper is to demonstrate the principle test equipment, instruments and the payload test matrix for an automatic test control. Electrical Ground Support Equipment (EGSE)/ Special Check out Equipment (SCOE) requirements, functions and architecture for C-band and Ku-band payloads are presented in details along with their interface with satellite during different phases of satellite testing. It provides test setup, in a single rack cabinet that can easily be moved from payload assembly and integration environment to thermal vacuum chamber all the way to launch site (for pre-launch test and verification).

High-resolution satellite imagery for mesoscale meteorological studies

NASA Technical Reports Server (NTRS)

Johnson, David B.; Flament, Pierre; Bernstein, Robert L.

1994-01-01

In this article high-resolution satellite imagery from a variety of meteorological and environmental satellites is compared. Digital datasets from Geostationary Operational Environmental Satellite (GOES), National Oceanic and Atmospheric Administration (NOAA), Defense Meteorological Satellite Program (DMSP), Landsat, and Satellite Pour l'Observation de la Terre (SPOT) satellites were archived as part of the 1990 Hawaiian Rainband Project (HaRP) and form the basis of the comparisons. During HaRP, GOES geostationary satellite coverage was marginal, so the main emphasis is on the polar-orbiting satellites.

TriAnd and its siblings: satellites of satellites in the Milky Way halo

NASA Astrophysics Data System (ADS)

Deason, A. J.; Belokurov, V.; Hamren, K. M.; Koposov, S. E.; Gilbert, K. M.; Beaton, R. L.; Dorman, C. E.; Guhathakurta, P.; Majewski, S. R.; Cunningham, E. C.

2014-11-01

We explore the Triangulum-Andromeda (TriAnd) overdensity in the SPLASH (Spectroscopic and Photometric Landscape of Andromeda's Stellar Halo) and SEGUE (the Sloan Extension for Galactic Understanding and Exploration) spectroscopic surveys. Milky Way main-sequence turn-off stars in the SPLASH survey reveal that the TriAnd overdensity and the recently discovered Pan-Andromeda Archaeological Survey (PAndAS) stream share a common heliocentric distance (D ˜ 20 kpc), position on the sky, and line-of-sight velocity (VGSR ˜ 50 km s-1). Similarly, A-type, giant, and main-sequence turn-off stars selected from the SEGUE survey in the vicinity of the Segue 2 satellite show that TriAnd is prevalent in these fields, with a velocity and distance similar to Segue 2. The coincidence of the PAndAS stream and Segue 2 satellite in positional and velocity space to TriAnd suggests that these substructures are all associated, and may be a fossil record of group-infall on to the Milky Way halo. In this scenario, the Segue 2 satellite and PAndAS stream are `satellites of satellites', and the large, metal-rich TriAnd overdensity is the remains of the group central.

Solar satellites

NASA Astrophysics Data System (ADS)

Poher, C.

A reference system design, projected costs, and the functional concepts of a satellite solar power system (SSPS) for converting sunlight falling on solar panels of a satellite in GEO to a multi-GW beam which could be received by a rectenna on earth are outlined. Electricity transmission by microwaves has been demonstrated, and a reference design system for supplying 5 GW dc to earth was devised. The system will use either monocrystalline Si or concentrator GaAs solar cells for energy collection in GEO. Development is still needed to improve the lifespan of the cells. Currently, the cell performance degrades 50 percent in efficiency after 7-8 yr in space. Each SSPS satellite would weigh either 34,000 tons (Si) or 51,000 tons (GaAs), thereby requiring the fabrication of a heavy lift launch vehicle or a single-stage-to-orbit transport in order to minimize launch costs. Costs for the solar panels have been estimated at $500/kW using the GaAs technology, with transport costs for materials to GEO being $40/kg.

Flight and ground tests of a GOES satellite time receiver for satellite communications applications

NASA Technical Reports Server (NTRS)

Swanson, R. L.; Nichols, S. A.

1981-01-01

A satellite time receiver was tested in various environmental conditions during the past year. The commercial receiver designed to work with the National Oceanic and Atmospheric Administration's (NOAA) Geostationary Operational Environmental Satellites (GOES). The test program included operation at low elevation during flight in a military cargo aircraft and long term comparison with laboratory standards. The GOES satellite time receiver offers an opportunity to provide easy wide area coverage synchronization at low cost.

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.

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.

AVS on satellite

NASA Astrophysics Data System (ADS)

Zhao, Haiwu; Wang, Guozhong; Hou, Gang

2005-07-01

AVS is a new digital audio-video coding standard established by China. AVS will be used in digital TV broadcasting and next general optical disk. AVS adopted many digital audio-video coding techniques developed by Chinese company and universities in recent years, it has very low complexity compared to H.264, and AVS will charge very low royalty fee through one-step license including all AVS tools. So AVS is a good and competitive candidate for Chinese DTV and next generation optical disk. In addition, Chinese government has published a plan for satellite TV signal directly to home(DTH) and a telecommunication satellite named as SINO 2 will be launched in 2006. AVS will be also one of the best hopeful candidates of audio-video coding standard on satellite signal transmission.

Direct recovery of mean gravity anomalies from satellite to satellite tracking

NASA Technical Reports Server (NTRS)

Hajela, D. P.

1974-01-01

The direct recovery was investigated of mean gravity anomalies from summed range rate observations, the signal path being ground station to a geosynchronous relay satellite to a close satellite significantly perturbed by the short wave features of the earth's gravitational field. To ensure realistic observations, these were simulated with the nominal orbital elements for the relay satellite corresponding to ATS-6, and for two different close satellites (one at about 250 km height, and the other at about 900 km height) corresponding to the nominal values for GEOS-C. The earth's gravitational field was represented by a reference set of potential coefficients up to degree and order 12, considered as known values, and by residual gravity anomalies obtained by subtracting the anomalies, implied by the potential coefficients, from their terrestrial estimates. It was found that gravity anomalies could be recovered from strong signal without using any a-priori terrestrial information, i.e. considering their initial values as zero and also assigning them a zero weight matrix. While recovering them from weak signal, it was necessary to use the a-priori estimate of the standard deviation of the anomalies to form their a-priori diagonal weight matrix.

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.

SOVCAN STAR: An international satellite system

NASA Astrophysics Data System (ADS)

Skatchkov, Valery A.

SOVCAN STAR is a Russian-Canadian cooperative venture company formed to manufacture, test, launch and operate a Ku-band satellite system. Drawing on the more than twenty years communications satellite experience of the founding companies, the SOVCAN STAR satellites are being designed to be competitive and cost effective. They will be equipped with 24 transponders and four steerable antennas. The design allows the operators to switch individual transponders between the various antenna coverage beams. These satellites will offer a high degree of operational flexibility and performance. The SOVCAN STAR strategy is to develop a network of satellites in parallel with the growth and evolution of the traffic requirements. Such an approach minimizes the technical, schedule and program risks while at the same time significantly reduces the financial exposure. The first SOVCAN STAR satellite will be commissioned in 1996 and operated at 14 deg W. The beams will be aligned to North America and Europe offering International service between Canada, the Eastern U.S.A., Europe, Russia and the Western C.I.S. Republics. The second SOVCAN STAR satellite will be commissioned a year later and operated at 145 deg E. This satellite will cover the Western Pacific Ocean, Eastern Asia and Australasia.

Muscle satellite cells adopt divergent fates

PubMed Central

Zammit, Peter S.; Golding, Jon P.; Nagata, Yosuke; Hudon, Valérie; Partridge, Terence A.; Beauchamp, Jonathan R.

2004-01-01

Growth, repair, and regeneration of adult skeletal muscle depends on the persistence of satellite cells: muscle stem cells resident beneath the basal lamina that surrounds each myofiber. However, how the satellite cell compartment is maintained is unclear. Here, we use cultured myofibers to model muscle regeneration and show that satellite cells adopt divergent fates. Quiescent satellite cells are synchronously activated to coexpress the transcription factors Pax7 and MyoD. Most then proliferate, down-regulate Pax7, and differentiate. In contrast, other proliferating cells maintain Pax7 but lose MyoD and withdraw from immediate differentiation. These cells are typically located in clusters, together with Pax7−ve progeny destined for differentiation. Some of the Pax7+ve/MyoD−ve cells then leave the cell cycle, thus regaining the quiescent satellite cell phenotype. Significantly, noncycling cells contained within a cluster can be stimulated to proliferate again. These observations suggest that satellite cells either differentiate or switch from terminal myogenesis to maintain the satellite cell pool. PMID:15277541

On orbital allotments for geostationary satellites

NASA Technical Reports Server (NTRS)

Gonsalvez, David J. A.; Reilly, Charles H.; Mount-Campbell, Clark A.

1986-01-01

The following satellite synthesis problem is addressed: communication satellites are to be allotted positions on the geostationary arc so that interference does not exceed a given acceptable level by enforcing conservative pairwise satellite separation. A desired location is specified for each satellite, and the objective is to minimize the sum of the deviations between the satellites' prescribed and desired locations. Two mixed integer programming models for the satellite synthesis problem are presented. Four solution strategies, branch-and-bound, Benders' decomposition, linear programming with restricted basis entry, and a switching heuristic, are used to find solutions to example synthesis problems. Computational results indicate the switching algorithm yields solutions of good quality in reasonable execution times when compared to the other solution methods. It is demonstrated that the switching algorithm can be applied to synthesis problems with the objective of minimizing the largest deviation between a prescribed location and the corresponding desired location. Furthermore, it is shown that the switching heuristic can use no conservative, location-dependent satellite separations in order to satisfy interference criteria.

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.

COSPAS-SARSAT Satellite Orbit Predictor. Volume 3

NASA Technical Reports Server (NTRS)

Friedman, Morton L.; Garrett, James

1984-01-01

The satellite orbit predictor is a graphical aid for determining the relationship between the satellite (SARSAT or COSPAS) orbit, antenna coverage of the spacecraft and coverage of the LUTs. 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. Additionally, a table of equator crossings for each satellite is included.

VLBI Observations of Geostationary Satellites

NASA Astrophysics Data System (ADS)

Artz, T.; Nothnagel, A.; La Porta, L.

2013-08-01

For a consistent realization of a Global Geodetic Observing System (GGOS), a proper tie between the individual global reference systems used in the analysis of space-geodetic observations is a prerequisite. For instance, the link between the terrestrial, the celestial and the dynamic reference system of artificial Earth orbiters may be realized by Very Long O Baseline Interferometry (VLBI) observations of one or several satellites. In the preparation phase for a dedicated satellite mission, one option to realize this is using a geostationary (GEO) satellite emitting a radio signal in X-Band and/or S-Band and, thus, imitating a quasar. In this way, the GEO satellite can be observed by VLBI together with nearby quasars and the GEO orbit can, thus, be determined in a celestial reference frame. If the GEO satellite is, e.g., also equipped with a GNSS-type transmitter, a further tie between GNSS and VLBI may be realized. In this paper, a concept for the generation of a radio signal is shown. Furthermore, simulation studies for estimating the GEO position are presented with a GEO satellite included in the VLBI schedule. VLBI group delay observations are then simulated for the quasars as well as for the GEO satellite. The analysis of the simulated observations shows that constant orbit changes are adequately absorbed by estimated orbit parameters. Furthermore, the post-fit residuals are comparable to those from real VLBI sessions.

Broadcast Satellite: "Appropriate Technology" Available Now

ERIC Educational Resources Information Center

Norwood, Frank W.

1978-01-01

Experimental broadcasting satellites make possible a cooperative and inexpensive communications system for use in remote areas of the world. Considered are their historical background, news dissemination, the SITE Project in India, NASA's ATS satellites, satellite classroom instruction, and Caribbean interests. (LBH)

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.

Small Cube Satellite Deploy

NASA Image and Video Library

2013-11-19

ISS038-E-003876 (19 Nov. 2013) --- Three nanosatellites, known as Cubesats, are featured in this image photographed by an Expedition 38 crew member on the International Space Station. The satellites were released outside the Kibo laboratory using a Small Satellite Orbital Deployer attached to the Japanese module's robotic arm on Nov. 19, 2013. Japan Aerospace Exploration Agency astronaut Koichi Wakata, flight engineer, monitored the satellite deployment while operating the Japanese robotic arm from inside Kibo. The Cubesats were delivered to the International Space Station Aug. 9, aboard Japan’s fourth H-II Transfer Vehicle, Kounotori-4.

Satellite-aided mobile radio concepts study: Concept definition of a satellite-aided mobile and personal radio communication system

NASA Technical Reports Server (NTRS)

Anderson, R. E.

1979-01-01

The satellite system requires the use of a large satellite antenna and spacecraft array power of about 12 kW or more depending on the operating frequency. Technology developments needed include large offset reflector multibeam antennas, satellite electrical power sybsystems providing greater than 12 kW of power, signal switching hardware, and linearized efficient solid state amplifiers for the satellite-aided mobile band. Presently there is no frequency assignment for this service, and it is recommended that an allocation be pursued. The satellite system appears to be within reasonable extrapolation of the state of the art. It is further recommended that the satellite-aided system spacecraft definition studies and supporting technology development be initiated.

TADPOLE satellite. [low cost synchronous orbit satellite to evaluate small mercury bombardment ion thruster applications

NASA Technical Reports Server (NTRS)

1974-01-01

A low cost synchronous orbit satellite to evaluate small mercury bombardment ion thruster applications is described. The ion thrusters provide the satellite with precise north-south and east-west stationkeeping capabilities. In addition, the thrusters are used to unload the reaction wheels used for attitude control and for other purposes described in the report. The proposed satellite is named TADPOLE. (Technology Application Demonstration Program of Low Energy).

Germany's Option for a Moon Satellite

NASA Astrophysics Data System (ADS)

Quantius, Dominik

The German non-profit amateur satellite organisation AMSAT-Deutschland successfully de-signed, built and launched four HEO satellites in the last three decades. Now they are going to build a satellite to leave the Earth orbit based on their flight-proven P3-D satellite design. Due to energetic constraints the most suitable launch date for the planned P5-A satellite to Mars will be in 2018. To efficiently use the relatively long time gap until launch a possible prior Moon mission came into mind. In co-operation with the DLR-Institute of Space Systems in Bremen, Germany, two studies on systems level for a first P5 satellite towards Moon and a following one towards Mars have been performed. By using the DLR's Concurrent Engineering Facility (CEF) two consistent satellite concepts were designed including mission analysis, configuration, propulsion, subsystem dimensioning, payload selection, budgeting and cost. The present paper gives an insight in the accomplished design process and the results of the performed study towards Moon. The developed Moon orbiter is designed to carry the following four main instruments besides flexible communication abilities: • slewable HDTV camera combined with a high gain antenna that allows receiving lunar television using a commercially available satellite TV dish on Earth • sensor imaging infrared spectrometer for mineralogy of lunar silicates and lunar surface temperature measurements • camera for detection and monitoring of impact flashes in visible light (VIS) on lunar night side caused by meteoroid impact events • camera technology test for interplanetary navigation and planetary approach navigation. This study presents a non-industrial satellite concept that could be launched as piggyback load on Ariane 5 into GTO. Due to the fact, that the satellite would be built by the private sector, the mission costs would remain low. Otherwise the scientific and public output would be high using that satellite bus for the instruments

One Web Satellites Ground Breaking

NASA Image and Video Library

2017-03-16

A model of a OneWeb satellite like those the company will build to will connect all areas of the world to the Internet wirelessly. The company plans to launch 2,000 of the satellites as part of its constellation. The satellites will be built at a new factory at Exploration Park at NASA's Kennedy Space Center. The company held a groundbreaking ceremony for the factory. Photo credit: NASA/Kim Shiflett

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.

Mobile satellite communications in the 1990's

NASA Astrophysics Data System (ADS)

Singh, Jai

1992-07-01

The evolution of Inmarsat global services from a single market and single service of the 1980's to all of the key mobile markets and a wide range of new terminals and services in the 1990's is described. An overview of existing mobile satellite services, as well as new services under implementation for introduction in the near and longer term, including a handheld satellite phone (Inmarsat-P), is provided. The initiative taken by Inmarsat in the integration of its global mobile satellite services with global navigation capability derived from GPS (Global Positioning System) and the GLONASS (Russian GPS) navigation satellite systems and the provision of an international civil overlay for GPS/GLONASS integrity and augmentation is highlighted. To complete the overview of the development of mobile satellite services in the 1990's, the known national and regional mobile satellite system plans and the various recent proposals for both orbiting and geostationary satellite systems for proving handheld satellite phone and/or data messaging services are described.

Transit satellite system timing capabilities

NASA Technical Reports Server (NTRS)

Finsod, T. D.

1978-01-01

Current time transfer capabilities of the Transit Satellite System are reviewed. Potential improvements in the changes in equipment and operational procedures using operational satellites are discussed.

Global satellite triangulation and trilateration for the National Geodetic Satellite Program (solutions WN 12, 14 and 16). [study and analysis of data from artificial satellites

NASA Technical Reports Server (NTRS)

Mueller, I. I.; Kumar, M.; Reilly, J. P.; Saxena, N.; Soler, T.

1973-01-01

A multi-year study and analysis of data from satellites launched specifically for geodetic purposes and from other satellites useful in geodetic studies was conducted. The program of work included theoretical studies and analysis for the geometric determination of station positions derived from photographic observations of both passive and active satellites and from range observations. The current status of data analysis, processing and results are examined.

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.

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.

Satellite cells say NO to radiation.

PubMed

Cho-Lim, Jennie J; Caiozzo, Vincent J; Tseng, Bertrand P; Giedzinski, Erich; Baker, Mike J; Limoli, Charles L

2011-05-01

Skeletal muscles are commonly exposed to radiation for diagnostic procedures and the treatment of cancers and heterotopic bone formation. Few studies have considered the impact of clinical doses of radiation on the ability of satellite cells (myogenic stem cells) to proliferate, differentiate and contribute to recovering/maintaining muscle mass. The primary objective of this study was to determine whether the proliferation of irradiated satellite cells could be rescued by manipulating NO levels via pharmacological approaches and mechanical stretch (which is known to increase NO levels). We used both SNP (NO donor) and PTIO (NO scavenger) to manipulate NO levels in satellite cells. We observed that SNP was highly effective in rescuing the proliferation of irradiated satellite cells, especially at doses less than 5 Gy. The potential importance of NO was further illustrated by the effects of PTIO, which completely inhibited the rescue effect of SNP. Mechanical cyclic stretch was found to produce significant increases in NO levels of irradiated satellite cells, and this was associated with a robust increase in satellite cell proliferation. The effects of both radiation and NO on two key myogenic regulatory factors (MyoD and myogenin) were also explored. Irradiation of satellite cells produced a significant increase in both MyoD and myogenin, effects that were mitigated by manipulating NO levels via SNP. Given the central role of myogenic regulatory factors in the proliferation and differentiation of satellite cells, the findings of the current study underscore the need to more fully understand the relationship between radiation, NO and the functionality of satellite cells.

Ionospheric Refraction Corrections in the GTDS for Satellite-To-Satellite Tracking Data

NASA Technical Reports Server (NTRS)

Nesterczuk, G.; Kozelsky, J. K.

1976-01-01

In satellite-to-satellite tracking (SST) geographic as well as diurnal ionospheric effects must be contended with, for the line of sight between satellites can cross a day-night interface or lie within the equatorial ionosphere. These various effects were examined and a method of computing ionospheric refraction corrections to range and range rate measurements with sufficient accuracy were devised to be used in orbit determinations. The Bent Ionospheric Model is used for SST refraction corrections. Making use of this model a method of computing corrections through large ionospheric gradients was devised and implemented into the Goddard Trajectory Determination System. The various considerations taken in designing and implementing this SST refraction correction algorithm are reported.

Satellite tracking of threatened species

USGS Publications Warehouse

Williams, M.; Lunsford, A.; Ellis, D.; Robinson, J.; Coronado, P.; Campbell, W.

1998-01-01

In 1990, a joint effort of two U.S. federal agencies, NASA Goddard Space Flight Center (GSFC) and the Patuxent Wildlife Research Center, began. We initially joined forces in a project that used satellite telemetry to discover the winter home of a tiny dwindling population of Siberian Cranes. Since then several projects have emerged, and a web site was created to follow some of these activities. This web site is called the Satellite Tracking of Threatened Species and its location is http://sdcd.gsfc.nasa.gov/ISTO/satellite_tracking. It describes the overall program, and links you to three subsections that describe the projects in more detail: Satellite Direct Readout, Birdtracks, and Birdworld.

One-Dimensional Hybrid Satellite Track Model for the Dynamics Explorer 2 (DE 2) Satellite

NASA Technical Reports Server (NTRS)

Deng, Wei; Killeen, T. L.; Burns, A. G.; Johnson, R. M.; Emery, B. A.; Roble, R. G.; Winningham, J. D.; Gary, J. B.

1995-01-01

A one-dimensional hybrid satellite track model has been developed to calculate the high-latitude thermospheric/ionospheric structure below the satellite altitude using Dynamics Explorer 2 (DE 2) satellite measurements and theory. This model is based on Emery et al. satellite track code but also includes elements of Roble et al. global mean thermosphere/ionosphere model. A number of parameterizations and data handling techniques are used to input satellite data from several DE 2 instruments into this model. Profiles of neutral atmospheric densities are determined from the MSIS-90 model and measured neutral temperatures. Measured electron precipitation spectra are used in an auroral model to calculate particle impact ionization rates below the satellite. These rates are combined with a solar ionization rate profile and used to solve the O(+) diffusion equation, with the measured electron density as an upper boundary condition. The calculated O(+) density distribution, as well as the ionization profiles, are then used in a photochemical equilibrium model to calculate the electron and molecular ion densities. The electron temperature is also calculated by solving the electron energy equation with an upper boundary condition determined by the DE 2 measurement. The model enables calculations of altitude profiles of conductivity and Joule beating rate along and below the satellite track. In a first application of the new model, a study is made of thermospheric and ionospheric structure below the DE 2 satellite for a single orbit which occurred on October 25, 1981. The field-aligned Poynting flux, which is independently obtained for this orbit, is compared with the model predictions of the height-integrated energy conversion rate. Good quantitative agreement between these two estimates has been reached. In addition, measurements taken at the incoherent scatter radar site at Chatanika (65.1 deg N, 147.4 deg W) during a DE 2 overflight are compared with the model

The predicted luminous satellite populations around SMC- and LMC-mass galaxies - a missing satellite problem around the LMC?

NASA Astrophysics Data System (ADS)

Dooley, Gregory A.; Peter, Annika H. G.; Carlin, Jeffrey L.; Frebel, Anna; Bechtol, Keith; Willman, Beth

2017-11-01

Recent discovery of many dwarf satellite galaxies in the direction of the Small and Large Magellanic Clouds (SMC and LMC) provokes questions of their origins, and what they can reveal about galaxy evolution theory. Here, we predict the satellite stellar mass function of Magellanic Cloud-mass host galaxies using abundance matching and reionization models applied to the Caterpillar simulations. Specifically focusing on the volume within 50 kpc of the LMC, we predict a mean of four to eight satellites with stellar mass M* > 104 M⊙, and three to four satellites with 80 < M* ≤ 3000 M⊙. Surprisingly, all 12 currently known satellite candidates have stellar masses of 80 < M* ≤ 3000 M⊙. Reconciling the dearth of large satellites and profusion of small satellites is challenging and may require a combination of a major modification of the M*-Mhalo relationship (steep, but with an abrupt flattening at 103 M⊙), late reionization for the Local Group (zreion ≲ 9 preferred) and/or strong tidal stripping. We can more robustly predict that ∼53 per cent of satellites within this volume were accreted together with the LMC and SMC and ∼47 per cent were only ever Milky Way satellites. Observing satellites of isolated LMC-sized field galaxies is essential to place the LMC in context, and to better constrain the M*-Mhalo relationship. Modelling known LMC-sized galaxies within 8 Mpc, we predict 1-6 (2-12) satellites with M* > 105 M⊙ (M* > 104 M⊙) within the virial volume of each, and 1-3 (1-7) within a single 1.5° diameter field of view, making their discovery likely.

Advanced mobile satellite communications using COMETS satellite in MM-wave and Ka-band

NASA Technical Reports Server (NTRS)

Ohmori, Shingo; Isobe, Shunkichi; Takeuchi, Makoto; Naito, Hideyuki

1993-01-01

Early in the 21st century, the demand for personal communications using mobile, hand-held, and VSAT terminals will rapidly increase. In a future system, many different types of services should be provided with one-hop connection. The Communications Research Laboratory (CRL) has studied a future advanced mobile satellite communications system using millimeter wave and Ka band. In 1990, CRL started the Communications and Broadcasting Engineering Test Satellite (COMETS) project. The satellite has been developed in conjunction with NASDA and will be launched in 1997. This paper describes the COMETS payload configuration and the experimental system for the advanced mobile communications mission.

Computing Thermal Imbalance Forces On Satellites

NASA Technical Reports Server (NTRS)

Vigue, Yvonne; Schutz, Robert E.; Sewell, Granville; Abusali, Pothai A. M.

1994-01-01

HEAT.PRO computer program calculates imbalance force caused by heating of surfaces of satellite. Calculates thermal imbalance force and determines its effect on orbit of satellite, especially where shadow cast by Earth Causes periodic changes in thermal environment around satellite. Written in FORTRAN 77.

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).

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.

A baseline maritime satellite communication system

NASA Technical Reports Server (NTRS)

Durrani, S. H.; Mcgregor, D. N.

1974-01-01

This paper describes a baseline system for maritime communications via satellite during the 1980s. The system model employs three geostationary satellites with global coverage antennas. Access to the system is controlled by a master station; user access is based on time-ordered polling or random access. Each Thor-Delta launched satellite has an RF power of 100 W (spinner) or 250 W (three-axis stabilized), and provides 10 equivalent duplex voice channels for up to 1500 ships with average waiting times of approximately 2.5 minutes. The satellite capacity is bounded by the available bandwidth to 50 such channels, which can serve up to 10,000 ships with an average waiting time of 5 minutes. The ships must have peak antenna gains of approximately 15.5 dB or 22.5 dB for the two cases (10 or 50 voice channels) when a spinner satellite is used; the required gains are 4 dB lower if a three-axis stabilized satellite is used. The ship antenna requirements can be reduced by 8 to 10 dB by employing a high-gain multi-beam phased array antenna on the satellite.

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

Exobiology of icy satellites

NASA Astrophysics Data System (ADS)

Simakov, M. B.

At the beginning of 2004 the total number of discovered planets near other stars was 119 All of them are massive giants and met practically in all orbits In a habitable zone from 0 8 up to 1 1 AU at less 11 planets has been found starting with HD 134987 and up to HD 4203 It would be naive to suppose existence of life in unique known to us amino-nucleic acid form on the gas-liquid giant planets Nevertheless conditions for onset and evolutions of life can be realized on hypothetical satellites extrasolar planets All giant planets of the Solar system have a big number of satellites 61 of Jupiter 52 of Saturn known in 2003 A small part of them consist very large bodies quite comparable to planets of terrestrial type but including very significant share of water ice Some from them have an atmosphere E g the mass of a column of the Titan s atmosphere exceeds 15 times the mass of the Earth atmosphere column Formation or capture of satellites is a natural phenomenon and satellite systems definitely should exist at extrasolar planets A hypothetical satellite of the planet HD 28185 with a dense enough atmosphere and hydrosphere could have biosphere of terrestrial type within the limits of our notion about an origin of terrestrial biosphere As an example we can see on Titan the largest satellite of Saturn which has a dense nitrogen atmosphere and a large quantity of liquid water under ice cover and so has a great exobiological significance The most recent models of the Titan s interior lead to the conclusion that a substantial liquid layer

Haystack Ultrawideband Satellite Imaging Radar

DTIC Science & Technology

2014-09-01

SEP 2014 2. REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Haystack Ultrawideband Satellite Imaging Radar 5a...www.ll.mit.edu September 2014 Since the launch of satellites into Earth orbits more than 50 years ago, space has become crowded. Commercial and military... satellites , both active and defunct, share the space environment with an assort- ment of space debris, such as remnants of damaged spacecraft and

Public Service Communication Satellite Program

NASA Technical Reports Server (NTRS)

Brown, J. P.

1977-01-01

The proposed NASA Public Service Communication Satellite Program consists of four different activities designed to fulfill the needs of public service sector. These are: interaction with the users, experimentation with existing satellites, development of a limited capability satellite for the earliest possible launch, and initiation of an R&D program to develop the greatly increased capability that future systems will require. This paper will discuss NASA efforts in each of these areas.

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.

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.

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.

Satellite missions, global environment, and the concept of a global satellite observation information network. The role of the committee on Earth observation satellites (CEOS)

NASA Astrophysics Data System (ADS)

Smith, D. Brent; Williams, David F.; Fujita, Akihiro

The paper traces the development of the Committee on Earth Observation Satellites (CEOS) since its November 1990 Plenary: its restructuring to include major intergovernmental user and international scientific organizational affiliates; its focus on data sharing issues and completion of a CEOS resolution guaranteeing global change researchers access to satellite data at the cost of filling a user request; unfolding of a CEOS-associated initiative of the UK Prime Minister reporting to UNCED delegations on the relevance of satellite missions to the study of the global environment; development of a "Dossier" providing detailed information on all CEOS agency satellite missions, including sensor specifications, ground systems, standard data products, and other information relevant to users; creation of a permanent CEOS Secretariat; and efforts currently underway to assess the feasibility of a global satellite observation information network. Of particular relevance to developing countries, the paper will discuss CEOS efforts to assure broad user access and to foster acceptance of applications in such important areas as disaster monitoring and mitigation, land cover change, weather forecasting, and long-term climate modeling.

Solar power satellites: The Engineering Challenges

NASA Technical Reports Server (NTRS)

Woodcock, G. R.

1978-01-01

Certain elements of solar power satellite design and system engineering studies are reviewed analyzing solar power satellites as a potential baseload electric power source. The complete system concept concept includes not only the satellites and their ground stations, but also the space transportation for delivery of the satellites, piece by piece, into space, and the factories for their construction in space. Issues related to carrying the solar power satellite concept from the present design study phase through implementation of actual hardware are considered. The first issue category is environmental aspects of the SPS systems. The second category of issues is the technology risks associated with achieving the necessary component and subsystem performances. The third category includes the engineering issues associated with carrying out such a large scale project. The fourth issue category is financial: the funding required to bring such a project into being and the costs of the satellites and resulting cost of the power produced as compared to potential alternative energy sources.

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.

On-board processing for future satellite communications systems: Satellite-Routed FDMA

NASA Astrophysics Data System (ADS)

Berk, G.; Christopher, P. F.; Hoffman, M.; Jean, P. N.; Rotholz, E.; White, B. E.

1981-05-01

A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented.

On-board processing for future satellite communications systems: Satellite-Routed FDMA

NASA Technical Reports Server (NTRS)

Berk, G.; Christopher, P. F.; Hoffman, M.; Jean, P. N.; Rotholz, E.; White, B. E.

1981-01-01

A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented.

NOAA Satellite and Information Service's International and Interagency

Science.gov Websites

FISHERIES CHARTING SATELLITES CLIMATE RESEARCH CAREERS Satellite and Data Policy Developing Partnerships Satellite and Information Service International and Interagency Affairs Office NOAA Satellite and , NESDIS IIAD facilitates the access, provision, and use of in situ and satellite data and products, and

Satellite orbit computation methods

NASA Technical Reports Server (NTRS)

1977-01-01

Mathematical and algorithmical techniques for solution of problems in satellite dynamics were developed, along with solutions to satellite orbit motion. Dynamical analysis of shuttle on-orbit operations were conducted. Computer software routines for use in shuttle mission planning were developed and analyzed, while mathematical models of atmospheric density were formulated.

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.

Initial results of centralized autonomous orbit determination of the new-generation BDS satellites with inter-satellite link measurements

NASA Astrophysics Data System (ADS)

Tang, Chengpan; Hu, Xiaogong; Zhou, Shanshi; Liu, Li; Pan, Junyang; Chen, Liucheng; Guo, Rui; Zhu, Lingfeng; Hu, Guangming; Li, Xiaojie; He, Feng; Chang, Zhiqiao

2018-01-01

Autonomous orbit determination is the ability of navigation satellites to estimate the orbit parameters on-board using inter-satellite link (ISL) measurements. This study mainly focuses on data processing of the ISL measurements as a new measurement type and its application on the centralized autonomous orbit determination of the new-generation Beidou navigation satellite system satellites for the first time. The ISL measurements are dual one-way measurements that follow a time division multiple access (TDMA) structure. The ranging error of the ISL measurements is less than 0.25 ns. This paper proposes a derivation approach to the satellite clock offsets and the geometric distances from TDMA dual one-way measurements without a loss of accuracy. The derived clock offsets are used for time synchronization, and the derived geometry distances are used for autonomous orbit determination. The clock offsets from the ISL measurements are consistent with the L-band two-way satellite, and time-frequency transfer clock measurements and the detrended residuals vary within 0.5 ns. The centralized autonomous orbit determination is conducted in a batch mode on a ground-capable server for the feasibility study. Constant hardware delays are present in the geometric distances and become the largest source of error in the autonomous orbit determination. Therefore, the hardware delays are estimated simultaneously with the satellite orbits. To avoid uncertainties in the constellation orientation, a ground anchor station that "observes" the satellites with on-board ISL payloads is introduced into the orbit determination. The root-mean-square values of orbit determination residuals are within 10.0 cm, and the standard deviation of the estimated ISL hardware delays is within 0.2 ns. The accuracy of the autonomous orbits is evaluated by analysis of overlap comparison and the satellite laser ranging (SLR) residuals and is compared with the accuracy of the L-band orbits. The results indicate

The Arctic Regional Communications Small SATellite (ARCSAT)

NASA Technical Reports Server (NTRS)

Casas, Joseph; Kress, Martin; Sims, William; Spehn, Stephen; Jaeger, Talbot; Sanders, Devon

2013-01-01

Traditional satellite missions are extremely complex and expensive to design, build, test, launch and operate. Consequently many complementary operational, exploration and research satellite missions are being formulated as a growing part of the future space community capabilities using formations of small, distributed, simple to launch and inexpensive highly capable small scale satellites. The Arctic Regional Communications small SATellite (ARCSAT) initiative would launch a Mini-Satellite "Mothership" into Polar or Sun Sync low-earth-orbit (LEO). Once on orbit, the Mothership would perform orbital insertion of four internally stored independently maneuverable nanosatellites, each containing electronically steerable antennas and reconfigurable software-defined radios. Unlike the traditional geostationary larger complex satellite communication systems, this LEO communications system will be comprised of initially a five small satellite formation that can be later incrementally increased in the total number of satellites for additional data coverage. ARCSAT will provide significant enabling capabilities in the Arctic for autonomous voice and data communications relay, Maritime Domain Awareness (MDA), data-extraction from unattended sensors, and terrestrial Search & Rescue (SAR) beacon detection missions throughout the "data starved desert" of the Arctic Region.

Satellite stratospheric aerosol measurement validation

NASA Technical Reports Server (NTRS)

Russell, P. B.; Mccormick, M. P.

1984-01-01

The validity of the stratospheric aerosol measurements made by the satellite sensors SAM II and SAGE was tested by comparing their results with each other and with results obtained by other techniques (lider, dustsonde, filter, and impactor). The latter type of comparison required the development of special techniques that convert the quantity measured by the correlative sensor (e.g. particle backscatter, number, or mass) to that measured by the satellite sensor (extinction) and quantitatively estimate the uncertainty in the conversion process. The results of both types of comparisons show agreement within the measurement and conversion uncertainties. Moreover, the satellite uncertainty is small compared to aerosol natural variability (caused by seasonal changes, volcanoes, sudden warmings, and vortex structure). It was concluded that the satellite measurements are valid.

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.

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.

The application of decommissioned GEO satellites to CAPS

NASA Astrophysics Data System (ADS)

Fu, S. Y.; Wang, Z. R.; Shi, H. L.; Ma, L. H.

2018-06-01

To ensure the reliable service of geostationary earth orbiting (GEO) communication satellites during the period of in-orbit, the hardware design life of each system usually has some redundancies in contrast to the limited fuel used to keep the satellite position and attitude. After the brief analysis of the life of the satellite subsystems, the feasibility of turning the decommissioned GEO communication satellites into slightly inclined geosynchronous orbiting (SIGSO) satellites is proved. In addition, the role and the actual usage of SIGSO satellites in Chinese Area Positioning System (CAPS) are analysed and discussed, including the effect on the improvement of Position Dilution of Precision (PDOP) of the navigation constellation and the application to satellite communication system, thus the potential value of satellite material and devices is exploited.

Monitoring Cyanobacteria with Satellites Webinar

EPA Pesticide Factsheets

real-world satellite applications can quantify cyanobacterial harmful algal blooms and related water quality parameters. Provisional satellite derived cyanobacteria data and different software tools are available to state environmental and health agencies.

Laser beamed power - Satellite demonstration applications

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Westerlund, Larry H.

1992-01-01

Feasibility of using a ground-based laser to beam light to the solar arrays of orbiting satellites to a level sufficient to provide the operating power required is discussed. An example case of a GEO communications satellite near the end of life due to radiation damage of the solar arrays or battery failure is considered. It is concluded that the commercial satellite industry should be able to reap significant economic benefits through the use of power beaming which is capable of providing supplemental power for satellites with failing arrays, or primary power for failed batteries.

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.

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.

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.

Odyssey, an optimized personal communications satellite system

NASA Astrophysics Data System (ADS)

Rusch, Roger J.

Personal communications places severe demands on service providers and transmission facilities. Customers are not satisfied with the current levels of service and want improvements. Among the characteristics that users seek are: lower service rates, hand held convenience, acceptable time delays, ubiquitous service, high availability, reliability, and high quality. The space industry is developing commercial space systems for providing mobile communications to personal telephones. Provision of land mobile satellite service is fundamentally different from the fixed satellite service provided by geostationary satellites. In fixed service, the earth based antennas can depend on a clear path from user to satellite. Mobile users in a terrestrial environment commonly encounter blockage due to vegetation, terrain or buildings. Consequently, high elevation angles are of premium value. TRW studied the issues and concluded that a Medium Earth Orbit constellation is the best solution for Personal Communications Satellite Service. TRW has developed Odyssey, which uses twelve satellites in medium altitude orbit to provide personal communications satellite service. The Odyssey communications system projects a multibeam antenna pattern to the Earth. The attitude control system orients the satellites to ensure constant coverage of land mass and coastal areas. Pointing can be reprogrammed by ground control to ensure optimized coverage of the desired service areas. The payload architecture features non-processing, "bent pipe" transponders and matrix amplifiers to ensure dynamic power delivery to high demand areas. Circuit capacity is 3000 circuits per satellite. Each satellite weighs 1917 kg (4226 pounds) at launch and the solar arrays provide 3126 Watts of power. Satellites are launched in pairs on Ariane, Atlas, or other vehicles. Each satellite is placed in a circular orbit at an altitude of 10,354 km. There are three orbit planes inclined at 55° to the equatorial plane

Odyssey, an optimized personal communications satellite system

NASA Astrophysics Data System (ADS)

Rusch, Roger J.

Personal communications places severe demands on service providers and transmission facilities. Customers are not satisfied with the current levels of service and want improvements. Among the characteristics that users seek are: lower service rates, hand held convenience, acceptable time delays, ubiquitous service, high availability, reliability, and high quality. The space industry in developing commercial space systems for providing mobile communications to personal telephones. Provision of land mobile satellite service is fundamentally different from the fixed satellite service provided by geostationary satellites. In fixed service, the earth based antennas can depend on a clear path from user to satellite. Mobile users in a terrestrial environment commonly encounter blockage due to vegetation, terrain or buildings. Consequently, high elevation angles are of premium value. TRW studied the issues and concluded that a Medium Earth Orbit constellation is the best solution for Personal Communications Satellite Service. TRW has developed Odyssey, which uses twelve satellites in medium altitude orbit to provide personal communications satellite service. The Odyssey communications system projects a multibeam antenna pattern to the Earth. The attitude control system orients the satellites to ensure constant coverage of land mass and coastal areas. Pointing can be reprogrammed by ground control to ensure optimized coverage of the desired service areas. The payload architecture features non-processing, 'bent pipe' transponders and matrix amplifiers to ensure dynamic power delivery to high demand areas. Circuit capacity is 3000 circuits per satellite. Each satellite weighs 1917 kg (4226 pounds) at launch and the solar arrays provide 3126 watts of power. Satellites are launched in pairs on Ariane, Atlas, or other vehicles. Each satellite is placed in a circular orbit at an altitude of 10,354 km.

Synchronized Position Hold, Engage, Reorient, Experimental Satellites

NASA Technical Reports Server (NTRS)

Miller, David W.; Wilson, Edward; How, Jonathan; Sanenz-Otero, Alvar; Chamitoff, Gregory

2009-01-01

Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) are bowling-ball sized spherical satellites. They will be used inside the space station to test a set of well-defined instructions for spacecraft performing autonomous rendezvous and docking maneuvers. Three free-flying spheres will fly within the cabin of the station, performing flight formations. Each satellite is self-contained with power, propulsion, computers and navigation equipment. The results are important for satellite servicing, vehicle assembly and formation flying spacecraft configurations. SPHERES is a testbed for formation flying by satellites, the theories and calculations that coordinate the motion of multiple bodies maneuvering in microgravity. To achieve this inside the ISS cabin, bowling-ball-sized spheres perform various maneuvers (or protocols), with one to three spheres operating simultaneously . The Synchronized Position Hold, Engage, Reorient, Experimental Satellites (SPHERES) experiment will test relative attitude control and station-keeping between satellites, re-targeting and image plane filling maneuvers, collision avoidance and fuel balancing algorithms, and an array of geometry estimators used in various missions. SPHERES consists of three self-contained satellites, which are 18 sided polyhedrons that are 0.2 meter in diameter and weigh 3.5 kilograms. Each satellite contains an internal propulsion system, power, avionics, software, communications, and metrology subsystems. The propulsion system uses CO2, which is expelled through the thrusters. SPHERES satellites are powered by AA batteries. The metrology subsystem provides real-time position and attitude information. To simulate ground station-keeping, a laptop will be used to transmit navigational data and formation flying algorithms. Once these data are uploaded, the satellites will perform autonomously and hold the formation until a new command is given.

Satellites | National Oceanic and Atmospheric Administration

Science.gov Websites

and understand our dynamic planet LATEST FEATURES // NOAA-20 satellite shares first polar view satellite (GOES-16) witnessed a frightening display of stratiform, or 'spider' lightning as it's known, in Earth DSCOVR, NOAA's first operational satellite in deep space, orbits a million miles from Earth in

Satellite RNAs of plant viruses: structures and biological effects.

PubMed Central

Roossinck, M J; Sleat, D; Palukaitis, P

1992-01-01

Plant viruses often contain parasites of their own, referred to as satellites. Satellite RNAs are dependent on their associated (helper) virus for both replication and encapsidation. Satellite RNAs vary from 194 to approximately 1,500 nucleotides (nt). The larger satellites (900 to 1,500 nt) contain open reading frames and express proteins in vitro and in vivo, whereas the smaller satellites (194 to 700 nt) do not appear to produce functional proteins. The smaller satellites contain a high degree of secondary structure involving 49 to 73% of their sequences, with the circular satellites containing more base pairing than the linear satellites. Many of the smaller satellites produce multimeric forms during replication. There are various models to account for their formation and role in satellite replication. Some of these smaller satellites encode ribozymes and are able to undergo autocatalytic cleavage. The enzymology of satellite replication is poorly understood, as is the replication of their helper viruses. In many cases the coreplication of satellites suppresses the replication of the helper virus genome. This is usually paralleled by a reduction in the disease induced by the helper virus; however, there are notable exceptions in which the satellite exacerbates the pathogenicity of the helper virus, albeit on only a limited number of hosts. The ameliorative satellites are being assessed as biocontrol agents of virus-induced disease. In greenhouse studies, satellites have been known to "spontaneously" appear in virus cultures. The possible origin of satellites will be briefly considered. PMID:1620065

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.

Study of chaos in chaotic satellite systems

NASA Astrophysics Data System (ADS)

Khan, Ayub; Kumar, Sanjay

2018-01-01

In this paper, we study the qualitative behaviour of satellite systems using bifurcation diagrams, Poincaré section, Lyapunov exponents, dissipation, equilibrium points, Kaplan-Yorke dimension etc. Bifurcation diagrams with respect to the known parameters of satellite systems are analysed. Poincaré sections with different sowing axes of the satellite are drawn. Eigenvalues of Jacobian matrices for the satellite system at different equilibrium points are calculated to justify the unstable regions. Lyapunov exponents are estimated. From these studies, chaos in satellite system has been established. Solution of equations of motion of the satellite system are drawn in the form of three-dimensional, two-dimensional and time series phase portraits. Phase portraits and time series display the chaotic nature of the considered system.

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

NASA Technical Reports Server (NTRS)

1978-01-01

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

Satellite imagery and discourses of transparency

NASA Astrophysics Data System (ADS)

Harris, Chad Vincent

In the last decade there has been a dramatic increase in satellite imagery available in the commercial marketplace and to the public in general. Satellite imagery systems and imagery archives, a knowledge domain formally monopolized by nation states, have become available to the public, both from declassified intelligence data and from fully integrated commercial vendors who create and market imagery data. Some of these firms have recently launched their own satellite imagery systems and created rather large imagery "architectures" that threaten to rival military reconnaissance systems. The increasing resolution of the imagery and the growing expertise of software and imagery interpretation developers has engendered a public discourse about the potentials for increased transparency in national and global affairs. However, transparency is an attribute of satellite remote sensing and imagery production that is taken for granted in the debate surrounding the growing public availability of high-resolution satellite imagery. This paper examines remote sensing and military photo reconnaissance imagery technology and the production of satellite imagery in the interests of contemplating the complex connections between imagery satellites, historically situated discourses about democratic and global transparency, and the formation and maintenance of nation state systems. Broader historical connections will also be explored between satellite imagery and the history of the use of cartographic and geospatial technologies in the formation and administrative control of nation states and in the discursive formulation of national identity. Attention will be on the technology itself as a powerful social actor through its connection to both national sovereignty and transcendent notions of scientific objectivity. The issues of the paper will be explored through a close look at aerial photography and satellite imagery both as communicative tools of power and as culturally relevant

Broadband Satellite Technologies and Markets Assessed

NASA Technical Reports Server (NTRS)

Wallett, Thomas M.

1999-01-01

The current usage of broadband (data rate greater than 64 kilobits per second (kbs)) for multimedia network computer applications is increasing, and the need for network communications technologies and systems to support this use is also growing. Satellite technology will likely be an important part of the National Information Infrastructure (NII) and the Global Information Infrastructure (GII) in the next decade. Several candidate communications technologies that may be used to carry a portion of the increased data traffic have been reviewed, and estimates of the future demand for satellite capacity have been made. A study was conducted by the NASA Lewis Research Center to assess the satellite addressable markets for broadband applications. This study effort included four specific milestones: (1) assess the changing nature of broadband applications and their usage, (2) assess broadband satellite and terrestrial technologies, (3) estimate the size of the global satellite addressable market from 2000 to 2010, and (4) identify how the impact of future technology developments could increase the utility of satellite-based transport to serve this market.

Heterochromatin-Encoded Satellite RNAs Induce Breast Cancer.

PubMed

Zhu, Quan; Hoong, Nien; Aslanian, Aaron; Hara, Toshiro; Benner, Christopher; Heinz, Sven; Miga, Karen H; Ke, Eugene; Verma, Sachin; Soroczynski, Jan; Yates, John R; Hunter, Tony; Verma, Inder M

2018-06-07

Heterochromatic repetitive satellite RNAs are extensively transcribed in a variety of human cancers, including BRCA1 mutant breast cancer. Aberrant expression of satellite RNAs in cultured cells induces the DNA damage response, activates cell cycle checkpoints, and causes defects in chromosome segregation. However, the mechanism by which satellite RNA expression leads to genomic instability is not well understood. Here we provide evidence that increased levels of satellite RNAs in mammary glands induce tumor formation in mice. Using mass spectrometry, we further show that genomic instability induced by satellite RNAs occurs through interactions with BRCA1-associated protein networks required for the stabilization of DNA replication forks. Additionally, de-stabilized replication forks likely promote the formation of RNA-DNA hybrids in cells expressing satellite RNAs. These studies lay the foundation for developing novel therapeutic strategies that block the effects of non-coding satellite RNAs in cancer cells. Copyright © 2018 Elsevier Inc. All rights reserved.

Satellite cells in human skeletal muscle plasticity

PubMed Central

Snijders, Tim; Nederveen, Joshua P.; McKay, Bryon R.; Joanisse, Sophie; Verdijk, Lex B.; van Loon, Luc J. C.; Parise, Gianni

2015-01-01

Skeletal muscle satellite cells are considered to play a crucial role in muscle fiber maintenance, repair and remodeling. Our knowledge of the role of satellite cells in muscle fiber adaptation has traditionally relied on in vitro cell and in vivo animal models. Over the past decade, a genuine effort has been made to translate these results to humans under physiological conditions. Findings from in vivo human studies suggest that satellite cells play a key role in skeletal muscle fiber repair/remodeling in response to exercise. Mounting evidence indicates that aging has a profound impact on the regulation of satellite cells in human skeletal muscle. Yet, the precise role of satellite cells in the development of muscle fiber atrophy with age remains unresolved. This review seeks to integrate recent results from in vivo human studies on satellite cell function in muscle fiber repair/remodeling in the wider context of satellite cell biology whose literature is largely based on animal and cell models. PMID:26557092

Intrinsic and extrinsic mechanisms regulating satellite cell function

PubMed Central

Dumont, Nicolas A.; Wang, Yu Xin; Rudnicki, Michael A.

2015-01-01

Muscle stem cells, termed satellite cells, are crucial for skeletal muscle growth and regeneration. In healthy adult muscle, satellite cells are quiescent but poised for activation. During muscle regeneration, activated satellite cells transiently re-enter the cell cycle to proliferate and subsequently exit the cell cycle to differentiate or self-renew. Recent studies have demonstrated that satellite cells are heterogeneous and that subpopulations of satellite stem cells are able to perform asymmetric divisions to generate myogenic progenitors or symmetric divisions to expand the satellite cell pool. Thus, a complex balance between extrinsic cues and intrinsic regulatory mechanisms is needed to tightly control satellite cell cycle progression and cell fate determination. Defects in satellite cell regulation or in their niche, as observed in degenerative conditions such as aging, can impair muscle regeneration. Here, we review recent discoveries of the intrinsic and extrinsic factors that regulate satellite cell behaviour in regenerating and degenerating muscles. PMID:25922523

Satellite interference analysis and simulation using personal computers

NASA Astrophysics Data System (ADS)

Kantak, Anil

1988-03-01

This report presents the complete analysis and formulas necessary to quantify the interference experienced by a generic satellite communications receiving station due to an interfering satellite. Both satellites, the desired as well as the interfering satellite, are considered to be in elliptical orbits. Formulas are developed for the satellite look angles and the satellite transmit angles generally related to the land mask of the receiving station site for both satellites. Formulas for considering Doppler effect due to the satellite motion as well as the Earth's rotation are developed. The effect of the interfering-satellite signal modulation and the Doppler effect on the power received are considered. The statistical formulation of the interference effect is presented in the form of a histogram of the interference to the desired signal power ratio. Finally, a computer program suitable for microcomputers such as IBM AT is provided with the flowchart, a sample run, results of the run, and the program code.

Satellite Interference Analysis and Simulation Using Personal Computers

NASA Technical Reports Server (NTRS)

Kantak, Anil

1988-01-01

This report presents the complete analysis and formulas necessary to quantify the interference experienced by a generic satellite communications receiving station due to an interfering satellite. Both satellites, the desired as well as the interfering satellite, are considered to be in elliptical orbits. Formulas are developed for the satellite look angles and the satellite transmit angles generally related to the land mask of the receiving station site for both satellites. Formulas for considering Doppler effect due to the satellite motion as well as the Earth's rotation are developed. The effect of the interfering-satellite signal modulation and the Doppler effect on the power received are considered. The statistical formulation of the interference effect is presented in the form of a histogram of the interference to the desired signal power ratio. Finally, a computer program suitable for microcomputers such as IBM AT is provided with the flowchart, a sample run, results of the run, and the program code.

Millimeter accuracy satellites for two color ranging

NASA Technical Reports Server (NTRS)

Degnan, John J.

1993-01-01

The principal technical challenge in designing a millimeter accuracy satellite to support two color observations at high altitudes is to provide high optical cross-section simultaneously with minimal pulse spreading. In order to address this issue, we provide, a brief review of some fundamental properties of optical retroreflectors when used in spacecraft target arrays, develop a simple model for a spherical geodetic satellite, and use the model to determine some basic design criteria for a new generation of geodetic satellites capable of supporting millimeter accuracy two color laser ranging. We find that increasing the satellite diameter provides: a larger surface area for additional cube mounting thereby leading to higher cross-sections; and makes the satellite surface a better match for the incoming planar phasefront of the laser beam. Restricting the retroreflector field of view (e.g. by recessing it in its holder) limits the target response to the fraction of the satellite surface which best matches the optical phasefront thereby controlling the amount of pulse spreading. In surveying the arrays carried by existing satellites, we find that European STARLETTE and ERS-1 satellites appear to be the best candidates for supporting near term two color experiments in space.

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.

Office of Satellite and Product Operations

Science.gov Websites

» OSPO Home » DOC » NOAA » NESDIS » OSPO NOAA Office of Satellite and Product Operations EMWIN GEONETCAST Americas GOES DCS LRIT NOAA Satellite Conferences NOAASIS SARSAT Products Atmosphere movements. GOES satellite imagery is also used to estimate rainfall during the thunderstorms and hurricanes

Regulation of Satellite Cell Function in Sarcopenia

PubMed Central

Alway, Stephen E.; Myers, Matthew J.; Mohamed, Junaith S.

2014-01-01

The mechanisms contributing to sarcopenia include reduced satellite cell (myogenic stem cell) function that is impacted by the environment (niche) of these cells. Satellite cell function is affected by oxidative stress, which is elevated in aged muscles, and this along with changes in largely unknown systemic factors, likely contribute to the manner in which satellite cells respond to stressors such as exercise, disuse, or rehabilitation in sarcopenic muscles. Nutritional intervention provides one therapeutic strategy to improve the satellite cell niche and systemic factors, with the goal of improving satellite cell function in aging muscles. Although many elderly persons consume various nutraceuticals with the hope of improving health, most of these compounds have not been thoroughly tested, and the impacts that they might have on sarcopenia and satellite cell function are not clear. This review discusses data pertaining to the satellite cell responses and function in aging skeletal muscle, and the impact that three compounds: resveratrol, green tea catechins, and β-Hydroxy-β-methylbutyrate have on regulating satellite cell function and therefore contributing to reducing sarcopenia or improving muscle mass after disuse in aging. The data suggest that these nutraceutical compounds improve satellite cell function during rehabilitative loading in animal models of aging after disuse (i.e., muscle regeneration). While these compounds have not been rigorously tested in humans, the data from animal models of aging provide a strong basis for conducting additional focused work to determine if these or other nutraceuticals can offset the muscle losses, or improve regeneration in sarcopenic muscles of older humans via improving satellite cell function. PMID:25295003

USEEIO Satellite Tables

EPA Pesticide Factsheets

These files contain the environmental data as particular emissions or resources associated with a BEA sectors that are used in the USEEIO model. They are organized by the emission or resources type, as described in the manuscript. The main files (without SI) show the final satellite tables in the 'Exchanges' sheet which have emissions or resource use per USD for 2013. The other sheets in these files provide meta data for the create of the tables, including general information, sources, etc. The 'export' sheet is used for saving the satellite table for csv export. The data dictionary describes the fields in this sheet. The supporting files provide all the details data transformation and organization for the development of the satellite tables.This dataset is associated with the following publication:Yang, Y., W. Ingwersen, T. Hawkins, and D. Meyer. USEEIO: a New and Transparent United States Environmentally Extended Input-Output Model. JOURNAL OF CLEANER PRODUCTION. Elsevier Science Ltd, New York, NY, USA,

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.

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.

47 CFR 25.279 - Inter-satellite service.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Technical Operations § 25.279 Inter-satellite service. (a) Any satellite communicating with other space stations may use frequencies in the inter-satellite service as indicated in § 2.106 of this chapter. This...

47 CFR 25.279 - Inter-satellite service.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Technical Operations § 25.279 Inter-satellite service. (a) Any satellite communicating with other space stations may use frequencies in the inter-satellite service as indicated in § 2.106 of this chapter. This...

47 CFR 25.279 - Inter-satellite service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Technical Operations § 25.279 Inter-satellite service. (a) Any satellite communicating with other space stations may use frequencies in the inter-satellite service as indicated in § 2.106 of this chapter. This...

47 CFR 25.279 - Inter-satellite service.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Technical Operations § 25.279 Inter-satellite service. (a) Any satellite communicating with other space stations may use frequencies in the inter-satellite service as indicated in § 2.106 of this chapter. This...

47 CFR 25.279 - Inter-satellite service.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Technical Operations § 25.279 Inter-satellite service. (a) Any satellite communicating with other space stations may use frequencies in the inter-satellite service as indicated in § 2.106 of this chapter. This...

FOREWORD: Satellite Remote Sensing Beyond 2015

NASA Technical Reports Server (NTRS)

Tucker, Compton J.

2017-01-01

Satellite remote sensing has progressed tremendously since the first Landsat was launched on June 23, 1972. Since the 1970s, satellite remote sensing and associated airborne and in situ measurements have resulted in vital and indispensable observations for understanding our planet through time. These observations have also led to dramatic improvements in numerical simulation models of the coupled atmosphere-land-ocean systems at increasing accuracies and predictive capability. The same observations document the Earth's climate and are driving the consensus that Homo sapiens is changing our climate through greenhouse gas emissions. These accomplishments are the combined work of many scientists from many countries and a dedicated cadre of engineers who build the instruments and satellites that collect Earth observation data from satellites, all working toward the goal of improving our understanding of the Earth. This edition of the Remote Sensing Handbook (Vol. I, II, and III) is a compendium of information for many research areas of our Planet that have contributed to our substantial progress since the 1970s. Remote sensing community is now using multiple sources of satellite and in situ data to advance our studies, what ever they might be. In the following paragraphs, I will illustrate how valuable and pivotal role satellite remote sensing has played in climate system study over last five decades, The Chapters in the Remote Sensing Handbook (Vol. I, II, and III) provides many other specific studies on land, water, and other applications using EO data of last five decades, The Landsat system of Earth-observing satellites has led the way in pioneering sustained observations of our planet. From 1972 to the present, at least one and sometimes two Landsat satellites have been in operation. Starting with the launch of the first NOAA-NASA Polar Orbiting Environmental Satellites NOAA-6 in 1978, improved imaging of land, clouds, and oceans and atmospheric soundings of

Satellite communications for disaster relief operations

NASA Technical Reports Server (NTRS)

Sivo, J. N.

1979-01-01

The use of existing and planned communication satellite systems to provide assistance in the implementation of disaster relief operations on a global basis was discussed along with satellite communications system implications and their potential impact on field operations in disaster situations. Consideration are given to the utilization of both INTELSAT and MARISAT systems operating at frequencies ranging from 1.5 to 4 GHz and to the size and type of ground terminals necessary for satellite access. Estimates of communication requirements for a global system are given. Some discussion of cost estimates for satellite services to support operations are included. Studies of communication satellites for both pre and post disaster applications conducted for NOAA are included as well as recent experiments conducted in conjunction with the Office of Foreign Disaster Assistance of the Agency for International Development.

Multibeam Aeronautical Satellite System Design.

DOT National Transportation Integrated Search

1971-12-01

A method is described which allows the identification of favored beam distributions for multiple beam aeronautical satellites. It is used to synthesize beam designs and compare the capacities of two satellite system configurations which cover the maj...

Anti-sway control of tethered satellite systems using attitude control of the main satellite

NASA Astrophysics Data System (ADS)

Yousefian, Peyman; Salarieh, Hassan

2015-06-01

In this study a new method is introduced to suppress libration of a tethered satellite system (TSS). It benefits from coupling between satellites and tether libration dynamics. The control concept uses the main satellite attitude maneuvers to suppress librational motion of the tether, and the main satellite's actuators for attitude control are used as the only actuation in the system. The study considers planar motion of a two body TSS system in a circular orbit and it is assumed that the tether's motion will not change it. Governing dynamic equations of motion are derived using the extended Lagrange method. Controllability of the system around the equilibrium state is studied and a linear LQG controller is designed to regulate libration of the system. Tether tension and satellite attitude are assumed as only measurable outputs of the system. The Extended Kalman Filter (EKF) is used to estimate states of the system to be used as feedback to the controller. The designed controller and observer are implemented to the nonlinear plant and simulations demonstrate that the controller lead to reduction of the tether libration propoerly. By the way, because the controller is linear, it is applicable only at low amplitudes in the vicinity of equilibrium point. To reach global stability, a nonlinear controller is demanded.

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.

Fine-tuning satellite-based rainfall estimates

NASA Astrophysics Data System (ADS)

Harsa, Hastuadi; Buono, Agus; Hidayat, Rahmat; Achyar, Jaumil; Noviati, Sri; Kurniawan, Roni; Praja, Alfan S.

2018-05-01

Rainfall datasets are available from various sources, including satellite estimates and ground observation. The locations of ground observation scatter sparsely. Therefore, the use of satellite estimates is advantageous, because satellite estimates can provide data on places where the ground observations do not present. However, in general, the satellite estimates data contain bias, since they are product of algorithms that transform the sensors response into rainfall values. Another cause may come from the number of ground observations used by the algorithms as the reference in determining the rainfall values. This paper describe the application of bias correction method to modify the satellite-based dataset by adding a number of ground observation locations that have not been used before by the algorithm. The bias correction was performed by utilizing Quantile Mapping procedure between ground observation data and satellite estimates data. Since Quantile Mapping required mean and standard deviation of both the reference and the being-corrected data, thus the Inverse Distance Weighting scheme was applied beforehand to the mean and standard deviation of the observation data in order to provide a spatial composition of them, which were originally scattered. Therefore, it was possible to provide a reference data point at the same location with that of the satellite estimates. The results show that the new dataset have statistically better representation of the rainfall values recorded by the ground observation than the previous dataset.

Multipath study for a low altitude satellite utilizing a data relay satellite system

NASA Technical Reports Server (NTRS)

Eggert, D.

1970-01-01

Technical considerations associated with a low altitude satellite operating in conjuction with a data relay satellite system are reported. Emphasis was placed on the quantitative characterization of multipath phenomenon and determination of power received via both the direct and earth reflection paths. Attempts were made to develop a means for estimating the magnitude and nature of the reflected power.

Solar power satellite, system definition study. Part 2, volume 3: SPS satellite systems

NASA Technical Reports Server (NTRS)

1977-01-01

The differences in approach to solar energy conversion by solar cells and thermal engine systems are examined. Systems requirements for the solar power satellite (SPS) are given along with a description of the primary subsystems. Trades leading to exact configuration selection, for example, selection of the Rankine cycle operating temperatures are explained, and two satellite configurations are discussed.

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

NASA Technical Reports Server (NTRS)

1972-01-01

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

Choosing ESRO's first scientific satellites

NASA Astrophysics Data System (ADS)

Russo, Arturo

1992-11-01

The choice of the scientific payloads of the European Space Research Organization's (ESRO's) first generation of satellites is analyzed. Concentration is on those aspects of the decision process that involved more directly the scientific community and that emerged as major issues in the discussion of the Launching Program Advisory Committee (LPAC). The main theme was the growing competition between the various fields of space science within the progressive retrenching of the Organization's financial resources available for the satellite program. A general overview of the status of the program by the end of 1966 is presented. The choice of the first small satellites' payloads (ESRO 1 and 2, and HEOS-A) and the difficult definition of the TD satellite program are discussed. This part covers a time span going from early 1963 to the spring of 1966. In the second part, the narrative starts from the spring of 1967, when the decision to recommend a second HEOS-type satellite was taken, and then analyzes the complex situation determined by the crisis of the TD program in 1968, and the debates which eventually led to the abandonment of TD-2 and the start of the far less ambitious ESRO 5 project.

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.

GEO Satellites as Space Weather Sensors

DTIC Science & Technology

2016-04-26

and analyzed >1 million hours of geostationary communications satellite housekeeping telemetry from commercial operators and have correlated the data...operational environment factors, and rank them by their their importance. 15. SUBJECT TERMS geostationary , satellite, communications, power...acquired  and  analyzed  >1  million  hours  of   geostationary  communications  satellite   housekeeping  telemetry  from

Land-mobile satellite communication system

NASA Technical Reports Server (NTRS)

Yan, Tsun-Yee (Inventor); Rafferty, William (Inventor); Dessouky, Khaled I. (Inventor); Wang, Charles C. (Inventor); Cheng, Unjeng (Inventor)

1993-01-01

A satellite communications system includes an orbiting communications satellite for relaying communications to and from a plurality of ground stations, and a network management center for making connections via the satellite between the ground stations in response to connection requests received via the satellite from the ground stations, the network management center being configured to provide both open-end service and closed-end service. The network management center of one embodiment is configured to provides both types of service according to a predefined channel access protocol that enables the ground stations to request the type of service desired. The channel access protocol may be configured to adaptively allocate channels to open-end service and closed-end service according to changes in the traffic pattern and include a free-access tree algorithm that coordinates collision resolution among the ground stations.

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.

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.

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.

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.

Advanced mobile satellite communications system using Ka and MM-wave bands in Japan's R and D satellite project

NASA Technical Reports Server (NTRS)

Isobe, Shunkichi; Ohmori, Shingo; Hamamoto, Naokazu; Yamamoto, Minoru

1991-01-01

Communications Research Laboratory (CRL) studied an advanced mobile satellite communications system using Ka and millimeter-wave bands in the R&D Satellite project. The project started in 1990 and the satellite will be launched in 1997. On-board multi-beam interconnecting is one of basic functions to realize one-hop connection among Very Small Aperture Terminals (VSATs), mobile, and hand-held terminals in future mobile satellite communications system. An Intermediate Frequency (IF) filter bank and regenerative transponder are suitable for this function. The transponder configuration of an advanced mobile communications mission of the R&D Satellite for experiment is shown. High power transmitters of Ka and millimeter-wave bands, a 3x3 IF filter band and Single Channel Per Carrier/Time Division Multiplexing (SCPC/TDM) regenerative MODEMS, which will be boarded on the R&D Satellite, are being developed for the purpose of studying the feasibility of advanced mobile communications system.

Color Survey of the Irregular Planetary Satellites

NASA Astrophysics Data System (ADS)

Graykowski, Ariel; Jewitt, David

2017-10-01

Irregular planetary satellites are characterized by their large orbital distance from their planet, their high eccentricity and their high inclination, all indicating that they were captured. However, the mechanism of capture and the source region of the satellites remain subjects of conjecture. This work presents the optical magnitudes and colors from a photometric survey of 42 irregular satellites with data obtained from the LRIS instrument on the 10-meter telescope at the Keck Observatory in Hawaii. Color is used as a proxy for composition. We compare the satellite populations of different planets and compare the satellites as a whole with other solar system small-body populations. For instance, if irregular satellites were captured from the Kuiper Belt, as is commonly proposed, then some might contain the ultrared material that is common in the trans-Neptunian and Centaur populations. Overall our data show that the irregular satellites lack ultrared matter. They are color-wise more similar to the comets, giant planet Trojans and other bodies of the middle solar system. Implications of our observations, and comparisons with previous color work, will be discussed.

Texstar: The all-Texas educational satellite system

NASA Technical Reports Server (NTRS)

1990-01-01

Longhorn Satellite Company (LSC) has designed Texstar, and educational satellite communications system which will be considered as a means of equalizing the distribution of educational resources throughout the state of Texas. Texstar will be capable of broadcasting live lectures and documentaries in addition to transmitting data from a centralized receiving-transmitting station. Included in the design of Texstar is the system and subsystem design for the satellite and the design of the ground stations. The launch vehicle used will be the Texas-built Conestoga 421-48. The Texstar system incorporates three small satellites in slightly inclined geosynchronous orbits. Due to the configuration and spacing of these satellites, the system will be accessed as if it were one large, geostationary satellite. Texstar is shown to be a viable option to the educational crisis in the state of Texas.

Capture of irregular satellites at Jupiter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio

The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encountersmore » with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10{sup –8}. This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.« less

Secure voice for mobile satellite applications

NASA Technical Reports Server (NTRS)

Vaisnys, Arvydas; Berner, Jeff

1990-01-01

The initial system studies are described which were performed at JPL on secure voice for mobile satellite applications. Some options are examined for adapting existing Secure Telephone Unit III (STU-III) secure telephone equipment for use over a digital mobile satellite link, as well as for the evolution of a dedicated secure voice mobile earth terminal (MET). The work has included some lab and field testing of prototype equipment. The work is part of an ongoing study at JPL for the National Communications System (NCS) on the use of mobile satellites for emergency communications. The purpose of the overall task is to identify and enable the technologies which will allow the NCS to use mobile satellite services for its National Security Emergency Preparedness (NSEP) communications needs. Various other government agencies will also contribute to a mobile satellite user base, and for some of these, secure communications will be an essential feature.

The 3D Radiation Dose Analysis For Satellite

NASA Astrophysics Data System (ADS)

Cai, Zhenbo; Lin, Guocheng; Chen, Guozhen; Liu, Xia

2002-01-01

the earth. These particles come from the Van Allen Belt, Solar Cosmic Ray and Galaxy Cosmic Ray. They have different energy and flux, varying with time and space, and correlating with solar activity tightly. These particles interact with electrical components and materials used on satellites, producing various space radiation effects, which will damage satellite to some extent, or even affect its safety. orbit. Space energy particles inject into components and materials used on satellites, and generate radiation dose by depositing partial or entire energy in them through ionization, which causes their characteristic degradation or even failure. As a consequence, the analysis and protection for radiation dose has been paid more attention during satellite design and manufacture. Designers of satellites need to analyze accurately the space radiation dose while satellites are on orbit, and use the results as the basis for radiation protection designs and ground experiments for satellites. can be calculated, using the model of the trapped proton and the trapped electron in the Van Allen Belt (AE8 and AP8). This is the 1D radiation dose analysis for satellites. Obviously, the mass shielding from the outside space to the computed point in all directions is regarded as a simple sphere shell. The actual structure of satellites, however, is very complex. When energy particles are injecting into a given equipment inside satellite from outside space, they will travel across satellite structure, other equipment, the shell of the given equipment, and so on, which depends greatly on actual layout of satellite. This complex radiation shielding has two characteristics. One is that the shielding masses for the computed point are different in different injecting directions. The other is that for different computed points, the shielding conditions vary in all space directions. Therefore, it is very difficult to tell the differences described above using the 1D radiation analysis, and

Effect of Ionosphere on Geostationary Communication Satellite Signals

NASA Astrophysics Data System (ADS)

Erdem, Esra; Arikan, Feza; Gulgonul, Senol

2016-07-01

Geostationary orbit (GEO) communications satellites allow radio, television, and telephone transmissions to be sent live anywhere in the world. They are extremely important in daily life and also for military applications. Since, satellite communication is an expensive technology addressing crowd of people, it is critical to improve the performance of this technology. GEO satellites are at 35,786 kilometres from Earth's surface situated directly over the equator. A satellite in a geostationary orbit (GEO) appears to stand still in the sky, in a fixed position with respect to an observer on the earth, because the satellite's orbital period is the same as the rotation rate of the Earth. The advantage of this orbit is that ground antennas can be fixed to point towards to satellite without their having to track the satellite's motion. Radio frequency ranges used in satellite communications are C, X, Ku, Ka and even EHG and V-band. Satellite signals are disturbed by atmospheric effects on the path between the satellite and the receiver antenna. These effects are mostly rain, cloud and gaseous attenuation. It is expected that ionosphere has a minor effect on the satellite signals when the ionosphere is quiet. But there are anomalies and perturbations on the structure of ionosphere with respect to geomagnetic field and solar activity and these conditions may cause further affects on the satellite signals. In this study IONOLAB-RAY algorithm is adopted to examine the effect of ionosphere on satellite signals. IONOLAB-RAY is developed to calculate propagation path and characteristics of high frequency signals. The algorithm does not have any frequency limitation and models the plasmasphere up to 20,200 km altitude, so that propagation between a GEO satellite and antenna on Earth can be simulated. The algorithm models inhomogeneous, anisotropic and time dependent structure of the ionosphere with a 3-D spherical grid geometry and calculates physical parameters of the

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.

Satellite voice broadcase system study. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Horstein, M.

1985-01-01

The feasibility of providing Voice of America (VOA) broadcasts by satellite relay was investigated. Satellite voice broadcast systems are described for three different frequency bands: HF, FHV, and L-band. Geostationary satellite configurations are considered for both frequency bands. A system of subsynchronous, circular satellites with an orbit period of 8 hours was developed for the HF band. The VHF broadcasts are provided by a system of Molniya satellites. The satellite designs are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. These satellites are comparable in size and weight to current satellites designed for the direct broadcast of video program material.

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

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.

Satellite-tracking and earth-dynamics research programs

NASA Technical Reports Server (NTRS)

1975-01-01

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

A Multi-Satellite GRACE-like Mission Using Small Satellites

NASA Astrophysics Data System (ADS)

Stephens, M.; Bender, P. L.; Nerem, R.; Pierce, R.; Wiese, D. N.

2010-12-01

Measurement of global water variation provides information critical to climate change and water resource monitoring. The Gravity Recovery and Climate Experiment II (GRACE II) was chosen as a Tier III mission by National Research Council's decadal survey because of its unique ability to measure the global mass distributions and variations in the mass distribution caused primarily by water variation. We discuss a multi-satellite approach to a GRACE-like mission. Enhanced spatial resolution of mass variations over those provided by the current GRACE mission can be achieved by improving the ranging accuracy; an interferometric ranging concept that improves the ranging accuracy has been demonstrated[1]. However, recent calculations show that to obtain the full science improvement using interferometric ranging, temporal aliasing errors due to modeling and to undersampling of geophysical signals must be mitigated[2]. One approach is to improve the data analysis techniques and validation processes. Another approach is to fly two or more pairs of satellites, thereby sampling the Earth's gravitational field at shorter time intervals[3]. A multiple-pair mission is often dismissed as too expensive, but the mission costs of a multiple-pair GRACE-like mission could be greatly reduced by developing compact ranging systems so that the mass, power, and volume usage is consistent with small spacecraft buses. Such size reduction drastically reduces the launch costs by allowing the spacecraft to be launched as auxiliary payloads. We will discuss the technological challenges that are associated with a GRACE-like mission that uses smallsats to reduce costs of more than one pair of satellites, as well as the scientific benefits of the two or more satellite pairs. The technological challenges include reducing the size of the payload and developing a low-drag, low-pointing jitter spacecraft. [1]Pierce, R., J. Leitch, M. Stephens, P. Bender, and R. Nerem, “Intersatellite range monitoring

Using satellite communications for a mobile computer network

NASA Technical Reports Server (NTRS)

Wyman, Douglas J.

1993-01-01

The topics discussed include the following: patrol car automation, mobile computer network, network requirements, network design overview, MCN mobile network software, MCN hub operation, mobile satellite software, hub satellite software, the benefits of patrol car automation, the benefits of satellite mobile computing, and national law enforcement satellite.

Solar array experiments on the SPHINX satellite. [Space Plasma High voltage INteraction eXperiment satellite

NASA Technical Reports Server (NTRS)

Stevens, N. J.

1974-01-01

The Space Plasma, High Voltage Interaction Experiment (SPHINX) is the name given to an auxiliary payload satellite scheduled to be launched in January 1974. The principal experiments carried on this satellite are specifically designed to obtain the engineering data on the interaction of high voltage systems with the space plasma. The classes of experiments are solar array segments, insulators, insulators with pin holes and conductors. The satellite is also carrying experiments to obtain flight data on three new solar array configurations: the edge illuminated-multijunction cells, the teflon encased cells, and the violet cells.

Global ring satellite communications system for future broadband network

NASA Astrophysics Data System (ADS)

Iida, Takashi; Suzuki, Yoshiaki; Arimoto, Yoshinori; Akaishi, Akira

2005-04-01

The purpose of this paper is to examine a cost model of a global ring satellite communications system as a 2G-satellite (second generation Internet satellite) for the future Internet satellite, whose capacity is around 120 Gbps. The authors proposed the future needs of research and development of communications satellite for the next 30 years and also proposed the approach of three generations for the future Internet satellites. First, the paper reviews and updates the original proposal for the future needs of communications satellite, considering the recent development of the quantum communication technology. It also examines the communications satellite applicability for bridging the digital divide in the Asia-Oceania as an example. The paper clarifies this possibility of communications satellite by showing various relationships among Internet penetration, land area, population growth, etc. Second, the cost of the global ring satellite is examined. The user terminal is considered as a combination of an earth terminal and wireless local area network for a user community. This paper shows that the global ring satellite has a possibility of a good cost-competitiveness to the terrestrial system because of the global communications system can be configured only by satellite system.

Hesr1 and Hesr3 are essential to generate undifferentiated quiescent satellite cells and to maintain satellite cell numbers

PubMed Central

Fukada, So-ichiro; Yamaguchi, Masahiko; Kokubo, Hiroki; Ogawa, Ryo; Uezumi, Akiyoshi; Yoneda, Tomohiro; Matev, Miroslav M.; Motohashi, Norio; Ito, Takahito; Zolkiewska, Anna; Johnson, Randy L.; Saga, Yumiko; Miyagoe-Suzuki, Yuko; Tsujikawa, Kazutake; Takeda, Shin’ichi; Yamamoto, Hiroshi

2011-01-01

Satellite cells, which are skeletal muscle stem cells, divide to provide new myonuclei to growing muscle fibers during postnatal development, and then are maintained in an undifferentiated quiescent state in adult skeletal muscle. This state is considered to be essential for the maintenance of satellite cells, but their molecular regulation is unknown. We show that Hesr1 (Hey1) and Hesr3 (Heyl) (which are known Notch target genes) are expressed simultaneously in skeletal muscle only in satellite cells. In Hesr1 and Hesr3 single-knockout mice, no obvious abnormalities of satellite cells or muscle regenerative potentials are observed. However, the generation of undifferentiated quiescent satellite cells is impaired during postnatal development in Hesr1/3 double-knockout mice. As a result, myogenic (MyoD and myogenin) and proliferative (Ki67) proteins are expressed in adult satellite cells. Consistent with the in vivo results, Hesr1/3-null myoblasts generate very few Pax7+ MyoD– undifferentiated cells in vitro. Furthermore, the satellite cell number gradually decreases in Hesr1/3 double-knockout mice even after it has stabilized in control mice, and an age-dependent regeneration defect is observed. In vivo results suggest that premature differentiation, but not cell death, is the reason for the reduced number of satellite cells in Hesr1/3 double-knockout mice. These results indicate that Hesr1 and Hesr3 are essential for the generation of adult satellite cells and for the maintenance of skeletal muscle homeostasis. PMID:21989910

The Use of a Satellite Human Interaction System in Conjunction with a Satellite Media Distribution System. Satellite Technology Demonstration, Technical Report No. 0217.

ERIC Educational Resources Information Center

Dale, Joyce B.

Satellite Technology Demonstration (STD) was designed to provide data on the use of a satellite to deliver educational programs to 56 rural-isolated schools in eight Rocky Mountain States. Three series were broadcast: (1) a junior high school career development, (2) career development for public school administrators and teachers, and (3) topical…

Satellite-Based Precipitation Datasets

NASA Astrophysics Data System (ADS)

Munchak, S. J.; Huffman, G. J.

2017-12-01

Of the possible sources of precipitation data, those based on satellites provide the greatest spatial coverage. There is a wide selection of datasets, algorithms, and versions from which to choose, which can be confusing to non-specialists wishing to use the data. The International Precipitation Working Group (IPWG) maintains tables of the major publicly available, long-term, quasi-global precipitation data sets (http://www.isac.cnr.it/ ipwg/data/datasets.html), and this talk briefly reviews the various categories. As examples, NASA provides two sets of quasi-global precipitation data sets: the older Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) and current Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) mission (IMERG). Both provide near-real-time and post-real-time products that are uniformly gridded in space and time. The TMPA products are 3-hourly 0.25°x0.25° on the latitude band 50°N-S for about 16 years, while the IMERG products are half-hourly 0.1°x0.1° on 60°N-S for over 3 years (with plans to go to 16+ years in Spring 2018). In addition to the precipitation estimates, each data set provides fields of other variables, such as the satellite sensor providing estimates and estimated random error. The discussion concludes with advice about determining suitability for use, the necessity of being clear about product names and versions, and the need for continued support for satellite- and surface-based observation.

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.

Next generation satellite communications networks

NASA Astrophysics Data System (ADS)

Garland, P. J.; Osborne, F. J.; Streibl, I.

The paper introduces two potential uses for new space hardware to permit enhanced levels of signal handling and switching in satellite communication service for Canada. One application involves increased private-sector services in the Ku band; the second supports new personal/mobile services by employing higher levels of handling and switching in the Ka band. First-generation satellite regeneration and switching experiments involving the NASA/ACTS spacecraft are described, where the Ka band and switching satellite network problems are emphasized. Second-generation satellite development is outlined based on demand trends for more packet-based switching, low-cost earth stations, and closed user groups. A demonstration mission for new Ka- and Ku-band technologies is proposed, including the payload configuration. The half ANIK E payload is shown to meet the demonstration objectives, and projected to maintain a fully operational payload for at least 10 years.

Satellite Remote Sensing of Aerosol Forcing

NASA Technical Reports Server (NTRS)

Remer, Lorraine; Kaufman, Yoram; Ramaprasad, Jaya; Procopio, Aline; Levin, Zev

1999-01-01

Aerosol and cloud impacts on the earth's climate become a recent hot topic in climate studies. Having near future earth observing satellites, EOS-AM1 (Earth Observing System-AM1), ENVISAT (Environmental Satellites) and ADEOS-2 (Advanced Earth Observation Satellite-2), it will be a good timing to discuss how to obtain and use the microphysical parameters of aerosols and clouds for studying their climate impacts. Center for Climate System Research (CCSR) of the University of Tokyo invites you to 'Symposium on synergy between satellite-remote sensing and climate modeling in aerosol and cloud issues.' Here, we like to discuss the current and future issues in the remote sensing of aerosol and cloud microphysical parameters and their climate modeling studies. This workshop is also one of workshop series on aerosol remote sensing held in 1996, Washington D. C., and Meribel, France in 1999. It should be reminded that NASDA/ADEOS-1 & -2 (National Space Development Agency of Japan/Advanced Earth Observation Satellite-1 & -2) Workshop will be held in the following week (Dec. 6-10, 1999), so that this opportunity will be a perfect period for you to attend two meetings for satellite remote sensing in Japan. A weekend in Kyoto, the old capital of Japan, will add a nice memory to your visiting Japan. *Issues in the symposium: 1) most recent topics in aerosol and cloud remot sensing, and 2) utility of satellite products on climate modeling of cloud-aerosol effects.

Satellite-Based Quantum Communications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hughes, Richard J; Nordholt, Jane E; McCabe, Kevin P

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 secretmore » 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.« less

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.

Satellite orbit determination using quantum correlation technology

NASA Astrophysics Data System (ADS)

Zhang, Bo; Sun, Fuping; Zhu, Xinhui; Jia, Xiaolin

2018-03-01

After the presentation of second-order correlation ranging principles with quantum entanglement, the concept of quantum measurement is introduced to dynamic satellite precise orbit determination. Based on the application of traditional orbit determination models for correcting the systematic errors within the satellite, corresponding models for quantum orbit determination (QOD) are established. This paper experiments on QOD with the BeiDou Navigation Satellite System (BDS) by first simulating quantum observations of 1 day arc-length. Then the satellite orbits are resolved and compared with the reference precise ephemerides. Subsequently, some related factors influencing the accuracy of QOD are discussed. Furthermore, the accuracy for GEO, IGSO and MEO satellites increase about 20, 30 and 10 times, respectively, compared with the results from the resolution by measured data. Therefore, it can be expected that quantum technology may also bring delightful surprises to satellite orbit determination as have already emerged in other fields.

Mini All-purpose Satellite Control Center (MASCC)

NASA Technical Reports Server (NTRS)

Zaouche, Gerard

1994-01-01

A new generation of Mini All-purpose Satellite Control Centers (MASCC) has been developed by CNES (F). They turn out to be easily adaptable to different kinds of satellites, both Low Earth Orbital or Geostationary. The features of MASCC allow both standard satellite control activities, and checking of passengers experiments hosted on a space platform. In the different environments in which it may be used, MASCC provides standard broadcasting of telemetry parameters on animated synoptics (curves, bar graphs, alphanumeric displays, ...), which turns out to be a very useful and ergonomic medium for operational teams or satellite specialists. Special care has been taken during the MASCC development about two points: - automation of all routine tasks, allowing automated operation, and limiting human commitment to system supervision and decision making, - software adaptability. To reach these two main objectives, the MASCC design provides:(1) a simple, robust and flexible hardware architecture, based on powerful distributed workstations; and (2) a table-driven software architecture, easily adapted to various operational needs. Satellite characteristics are described in a central Data Base. Hence, the processing of telemetry and commands is largely independent from the satellite itself. In order to validate these capabilities, the MASCC has been customized to several types of satellites and orbital platforms: (1) SPOT4, the French new generation of remote sensing satellites; (2) TELECOM2, the French geostationary TV and telecommunication satellite; and (3) MIR, the Russian orbital platform. MASCC development has been completed by the third quarter of 1993. This paper will provide first a description of the MASCC basic functions, of its hardware and software design. It will then detail the increased automation capability, along with the easy adaptation of the MASCC to new satellites with minimal software modifications.

Protected transitional solution to transformational satellite communications

NASA Astrophysics Data System (ADS)

Brand, Jerry C.

2005-06-01

As the Warfighter progresses into the next generation battlefield, transformational communications become evident as an enabling technology. Satellite communications become even more vital as the battles range over greater non-contiguous spaces. While current satellite communications provide suitable beyond line-of-sight communications and the Transformational Communications Architecture (TCA) sets the stage for sound information exchange, a realizable transition must occur to ensure successful succession to this higher level. This paper addresses the need for a planned escalation to the next generation satellite communications architecture and offers near-term alternatives. Commercial satellite systems continue to enable the Warfighter to reach back to needed information resources, providing a large majority of available bandwidth. Four areas of concentration for transition include encrypted Telemetry, Tracking and Control (or Command) (TT&C), encrypted and covered data, satellite attack detection and protection, and operational mobility. Solution methodologies include directly embedding COMSEC devices in the satellites and terminals, and supplementing existing terminals with suitable equipment and software. Future satellites planned for near-term launches can be adapted to include commercial grade and higher-level secure equipment. Alternately, the expected use of programmable modems (Software Defined Radios (SDR)) enables incorporation of powerful cipher methods approaching military standards as well as waveforms suitable for on-the-move operation. Minimal equipment and software additions on the satellites can provide reasonable attack detection and protection methods in concert with the planned satellite usage. Network management suite modifications enable cohesive incorporation of these protection schemes. Such transitional ideas offer a smooth and planned transition as the TCA takes life.

Satellite networks in the ISDN era

NASA Astrophysics Data System (ADS)

Amadesi, P.; Haines, P.; Patacchini, A.

1986-12-01

The development of an integrated service digital network (ISDN) capable of supporting a wide range of services using a small set of standard multipurpose user-network interfaces is examined. The ISDN environment is expected to consist of functional elements such as, circuit switching, packet switching, and common channel signaling. The use of satellites or fiber optics in the ISDN is evaluated. The relation between satellites and the ISDN in the short-, medium-, and long-terms is analyzed. The recommendations of the consultative committee, CCIR, concerning the definition of the hypothetical reference digital path and the required quality and availability for ISDN applications, and the proposed plans of Eutelsat and Intelsat for satellite systems compatible with an ISDN are discussed. The application of business satellite networks and packet satellite networks to an ISDN is studied. The long-term objectives for an ISDN is a wideband system that accommodates digital transmission on circuit and packet switched bases.

Mathematical programming formulations for satellite synthesis

NASA Technical Reports Server (NTRS)

Bhasin, Puneet; Reilly, Charles H.

1987-01-01

The problem of satellite synthesis can be described as optimally allotting locations and sometimes frequencies and polarizations, to communication satellites so that interference from unwanted satellite signals does not exceed a specified threshold. In this report, mathematical programming models and optimization methods are used to solve satellite synthesis problems. A nonlinear programming formulation which is solved using Zoutendijk's method and a gradient search method is described. Nine mixed integer programming models are considered. Results of computer runs with these nine models and five geographically compatible scenarios are presented and evaluated. A heuristic solution procedure is also used to solve two of the models studied. Heuristic solutions to three large synthesis problems are presented. The results of our analysis show that the heuristic performs very well, both in terms of solution quality and solution time, on the two models to which it was applied. It is concluded that the heuristic procedure is the best of the methods considered for solving satellite synthesis problems.

Landsat—Earth observation satellites

USGS Publications Warehouse

,

2015-11-25

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

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.

Small Aperture Telescope Observations of Co-located Geostationary Satellites

NASA Astrophysics Data System (ADS)

Scott, R.; Wallace, B.

As geostationary orbit (GEO) continues to be populated, satellite operators are increasing usage of co-location techniques to maximize usage of fewer GEO longitude slots. Co-location is an orbital formation strategy where two or more geostationary satellites reside within one GEO stationkeeping box. The separation strategy used to prevent collision between the co-located satellites generally uses eccentricity (radial separation) and inclination (latitude separation) vector offsets. This causes the satellites to move in relative motion ellipses about each other as the relative longitude drift between the satellites is near zero. Typical separations between the satellites varies from 1 to 100 kilometers. When co-located satellites are observed by optical ground based space surveillance sensors the participants appear to be separated by a few minutes of arc or less in angular extent. Under certain viewing geometries, these satellites appear to visually conjunct even though the satellites are, in fact, well separated spatially. In situations where one of the co-located satellites is more optically reflective than the other, the reflected sunglint from the more reflective satellite can overwhelm the other. This less frequently encountered issue causes the less reflective satellite to be glint masked in the glare of the other. This paper focuses on space surveillance observations on co-located Canadian satellites using a small optical telescope operated by Defence R&D Canada - Ottawa. The two above mentioned problems (cross tagging and glint masking) are investigated and we quantify the results for Canadian operated geostationary satellites. The performance of two line element sets when making in-frame CCD image correlation between the co-located satellites is also examined. Relative visual magnitudes between the co-located members are also inspected and quantified to determine the susceptibility of automated telescopes to glint masking of co-located satellite members.

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.

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.

TDRSS Augmentation Service for Satellites (TASS)

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.

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.

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.

A Survey of Geosynchronous Satellite Glints

DTIC Science & Technology

2009-09-01

particular, 8 consecutive nights of photometry were obtained of DirecTV-9S which show the evolution of glints from that satellite . This is of particular...off the spacecraft, which dominates most of the phase angle signatures. However, at times of favorable alignment between the satellite , observer and... timing , shapes, and durations of the glints along with notional glint models. We also briefly discuss glints from other satellites in the constellation

Small Satellite Constellations for Geospace Sciences

NASA Astrophysics Data System (ADS)

Spence, H. E.

2016-12-01

The recent National Academy of Sciences Solar and Space Physics Decadal Survey (DS) identified community-consensus science priorities for the decade spanning 2013 - 2022. In this talk, we discuss the ways by which small satellite constellations are already and may soon accelerate progress toward achieving many of these science targets. The DS outlined four overarching science goals: (1) determine the origins of the Sun's activity and predict the variations in the space environment; (2) determine the dynamics and coupling of Earth's magnetosphere, ionosphere, and atmosphere and their response to solar and terrestrial inputs; (3) determine the interaction of the Sun with the solar system and the interstellar medium; and, (4) discover and characterize fundamental processes that occur both within the heliosphere and throughout the universe. These DS science goals provide the context for key science challenges in the three connected parts of the system that encompass all of solar and space physics, herein referred to as geospace: the Sun and heliosphere; the coupled solar wind-magnetosphere system; and, the coupled atmosphere-ionosphere-magnetosphere system. The DS further presented the role that small satellites play in resolving many of these science challenges, with a particular emphasis on the role that constellations of small satellites will play. While once considered by many as being "futuristic" or even "unrealizable", constellations of small satellites are already making important contributions to geospace science and with the promise for more to come. Using the DS as a guidepost, in this presentation, we outline representative small satellite constellation missions alread underway, some in development, and others notionally proposed over the next several years that employ small satellite constellations to tackle large science imperatives. Finally, we give examples of key small satellite technologies in development that will potentially enable great scientific

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.

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.

Low Earth Orbit satellite traffic simulator

NASA Technical Reports Server (NTRS)

Hoelzel, John

1995-01-01

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

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.

Satellite DNA: An Evolving Topic

PubMed Central

Garrido-Ramos, Manuel A.

2017-01-01

Satellite DNA represents one of the most fascinating parts of the repetitive fraction of the eukaryotic genome. Since the discovery of highly repetitive tandem DNA in the 1960s, a lot of literature has extensively covered various topics related to the structure, organization, function, and evolution of such sequences. Today, with the advent of genomic tools, the study of satellite DNA has regained a great interest. Thus, Next-Generation Sequencing (NGS), together with high-throughput in silico analysis of the information contained in NGS reads, has revolutionized the analysis of the repetitive fraction of the eukaryotic genomes. The whole of the historical and current approaches to the topic gives us a broad view of the function and evolution of satellite DNA and its role in chromosomal evolution. Currently, we have extensive information on the molecular, chromosomal, biological, and population factors that affect the evolutionary fate of satellite DNA, knowledge that gives rise to a series of hypotheses that get on well with each other about the origin, spreading, and evolution of satellite DNA. In this paper, I review these hypotheses from a methodological, conceptual, and historical perspective and frame them in the context of chromosomal organization and evolution. PMID:28926993

Orbit-spectrum sharing between the fixed-satellite and broadcasting-satellite services with applications to 12 GHz domestic systems

NASA Technical Reports Server (NTRS)

Reinhart, E. E.

1974-01-01

A systematic, tutorial analysis of the general problem of orbit-spectrum sharing among inhomogeneous satellite system is presented. Emphasis is placed on extrapolating and applying the available data on rain attenuation and on reconciling differences in the results of various measurements of the subjective effects of interference on television picture quality. An analytic method is presented for determining the approximate values of the intersatellite spacings required to keep mutual interference levels within prescribed limits when many dissimilar satellites share the orbit. A computer model was developed for assessing the interference compatibility of arbitrary configurations of large numbers of geostationary satellite systems. It is concluded that the band from 11.7 c GHz can be shared effectively by broadcasting-satellite and fixed-satellite systems. Recommendations for future study are included.

BRITE-PL: the first Polish scientific satellite

NASA Astrophysics Data System (ADS)

Orleanski, Piotr; Graczyk, Rafal; Rataj, Miroslaw; Schwarzenberg-Czerny, Aleksander; Zawistowski, Tomasz; Zee, Robert E.

2010-09-01

The participation in BRITE Consortium gives Poland the possibility to launch into space the first Polish scientific satellite. This paper presents the Polish technical contribution to the BRITE Program to be realized in two institutes of the Polish Academy of Sciences: Nicolaus Copernicus Astronomical Center and Space Research Center.. BRITE Constellation, short for "BRIght Target Explorer Constellation," is a group of up to six nano-satellites whose purpose is to photometrically measure low-level oscillations and temperature variations in the sky's 286 stars brighter than visual magnitude 3.5, with unprecedented precision and time sampling not achievable through terrestrial-based methods. The three-axis pointing performance (1 arc minute rms stability) of each BRITE satellite is a significant advancement over anything that has ever flown before on a nano-satellite and is an important factor that enables the high precision photometry mission. The paper summarizes the technical details of the BRITE satellite based on Generic Nanosatellite Bus from SFL/UTIAS. The first Polish satellite, BRITE -PL 1, will be a modified version of the original SFL design. The second Polish satellite, BRITE-PL 2, will include the significant changes to be implemented by SRC PAS.

Dynamic system simulation of small satellite projects

NASA Astrophysics Data System (ADS)

Raif, Matthias; Walter, Ulrich; Bouwmeester, Jasper

2010-11-01

A prerequisite to accomplish a system simulation is to have a system model holding all necessary project information in a centralized repository that can be accessed and edited by all parties involved. At the Institute of Astronautics of the Technische Universitaet Muenchen a modular approach for modeling and dynamic simulation of satellite systems has been developed called dynamic system simulation (DySyS). DySyS is based on the platform independent description language SysML to model a small satellite project with respect to the system composition and dynamic behavior. A library of specific building blocks and possible relations between these blocks have been developed. From this library a system model of the satellite of interest can be created. A mapping into a C++ simulation allows the creation of an executable system model with which simulations are performed to observe the dynamic behavior of the satellite. In this paper DySyS is used to model and simulate the dynamic behavior of small satellites, because small satellite projects can act as a precursor to demonstrate the feasibility of a system model since they are less complex compared to a large scale satellite project.

PRMT7 Preserves Satellite Cell Regenerative Capacity.

PubMed

Blanc, Roméo Sébastien; Vogel, Gillian; Chen, Taiping; Crist, Colin; Richard, Stéphane

2016-02-16

Regeneration of skeletal muscle requires the continued presence of quiescent muscle stem cells (satellite cells), which become activated in response to injury. Here, we report that whole-body protein arginine methyltransferase PRMT7(-/-) adult mice and mice conditionally lacking PRMT7 in satellite cells using Pax7-CreERT2 both display a significant reduction in satellite cell function, leading to defects in regenerative capacity upon muscle injury. We show that PRMT7 is preferentially expressed in activated satellite cells and, interestingly, PRMT7-deficient satellite cells undergo cell-cycle arrest and premature cellular senescence. These defects underlie poor satellite cell stem cell capacity to regenerate muscle and self-renew after injury. PRMT7-deficient satellite cells express elevated levels of the CDK inhibitor p21CIP1 and low levels of its repressor, DNMT3b. Restoration of DNMT3b in PRMT7-deficient cells rescues PRMT7-mediated senescence. Our findings define PRMT7 as a regulator of the DNMT3b/p21 axis required to maintain muscle stem cell regenerative capacity. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

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.

Satellite Power Systems (SPS) concept definition study. Volume 5: Special emphasis studies. [rectenna and solar power satellite design studies

NASA Technical Reports Server (NTRS)

Hanley, G. M.

1980-01-01

Satellite configurations based on the Satellite Power System baseline requirements were analyzed and a preferred concept selected. A satellite construction base was defined, precursor operations incident to establishment of orbital support facilities identified, and the satellite construction sequence and procedures developed. Rectenna construction requirement were also addressed. Mass flow to orbit requirements were revised and traffic models established based on construction of 60 instead of 120 satellites. Analyses were conducted to determine satellite control, resources, manufacturing, and propellant requirements. The impact of the laser beam used for space-to-Earth power transmission upon the intervening atmosphere was examined as well as the inverse effect. The significant space environments and their effects on spacecraft components were investigated to define the design and operational limits imposed by the environments on an orbit transfer vehicle. The results show that LEO altitude 300 nmi and transfer orbit duration 6 months are preferrable.

Applications based on restored satellite images

NASA Astrophysics Data System (ADS)

Arbel, D.; Levin, S.; Nir, M.; Bhasteker, I.

2005-08-01

Satellites orbit the earth and obtain imagery of the ground below. The quality of satellite images is affected by the properties of the atmospheric imaging path, which degrade the image by blurring it and reducing its contrast. Applications involving satellite images are many and varied. Imaging systems are also different technologically and in their physical and optical characteristics such as sensor types, resolution, field of view (FOV), spectral range of the acquiring channels - from the visible to the thermal IR (TIR), platforms (mobilization facilities; aircrafts and/or spacecrafts), altitude above ground surface etc. It is important to obtain good quality satellite images because of the variety of applications based on them. The more qualitative is the recorded image, the more information is yielded from the image. The restoration process is conditioned by gathering much data about the atmospheric medium and its characterization. In return, there is a contribution to the applications based on those restorations i.e., satellite communication, warfare against long distance missiles, geographical aspects, agricultural aspects, economical aspects, intelligence, security, military, etc. Several manners to use restored Landsat 7 enhanced thematic mapper plus (ETM+) satellite images are suggested and presented here. In particular, using the restoration results for few potential geographical applications such as color classification and mapping (roads and streets localization) methods.

An optimization tool for satellite equipment layout

NASA Astrophysics Data System (ADS)

Qin, Zheng; Liang, Yan-gang; Zhou, Jian-ping

2018-01-01

Selection of the satellite equipment layout with performance constraints is a complex task which can be viewed as a constrained multi-objective optimization and a multiple criteria decision making problem. The layout design of a satellite cabin involves the process of locating the required equipment in a limited space, thereby satisfying various behavioral constraints of the interior and exterior environments. The layout optimization of satellite cabin in this paper includes the C.G. offset, the moments of inertia and the space debris impact risk of the system, of which the impact risk index is developed to quantify the risk to a satellite cabin of coming into contact with space debris. In this paper an optimization tool for the integration of CAD software as well as the optimization algorithms is presented, which is developed to automatically find solutions for a three-dimensional layout of equipment in satellite. The effectiveness of the tool is also demonstrated by applying to the layout optimization of a satellite platform.

Introduction to Satellite Communications.

DTIC Science & Technology

1974-04-15

diagram. . 9-18 9-14 Three basic oscillator configurations functional diagram. 9-20 9-15 Oneshot emitter coupled monostable multivibrator schematic...recognized the potential advantages inherent in the use of satellites and have had research and development programs in effect for a number of years...Radio Relays. The United States has long been interested in satellites for a variety of reasons, and research in this field has been accelerated since

Satellite Photometric Error Determination

DTIC Science & Technology

2015-10-18

the GEO Color Photometry Catalog (GCPC) that tried to remedy some of the problems listed above for geostationary satellites. In particular, we... Geostationary objects over the continental US  Develop new feature extraction methods such as albedo-area measurements  Understanding of seasonal...Fig. 4 and Fig. 5, there are examples of color photometry signatures for a 3-axis stabilized geostationary satellite. The data were taken with a

Satellite deployment during STS-5

NASA Image and Video Library

1982-11-17

S82-39793 (11 Nov. 1982) --- The Satellite Business Systems (SBS-3) spacecraft springs from its protective ?cradle? in the cargo bay of the Earth-orbiting space shuttle Columbia and head toward a series of maneuvers that will eventually place it in a geosynchronous orbit. This moment marks a milestone for the Space Transportation System (STS) program, as the placement of the communications satellites represents the first deployment of a commercial satellite from an orbiting space vehicle. Part of Columbia?s wings can be seen on both the port and starboard sides. Also both orbital maneuvering system (OMS) pods are seen at center. The vertical stabilizer is obscured by the satellite. The closed protective cradle device shielding Telesat Canada?s ANIK C-3 spacecraft is seen between the other shield and the OMS pod. ANIK is to be launched on the mission?s second day. This photograph was exposed through the aft windows of the flight deck. Photo credit: NASA

Satellite Image Classification of Building Damages Using Airborne and Satellite Image Samples in a Deep Learning Approach

NASA Astrophysics Data System (ADS)

Duarte, D.; Nex, F.; Kerle, N.; Vosselman, G.

2018-05-01

The localization and detailed assessment of damaged buildings after a disastrous event is of utmost importance to guide response operations, recovery tasks or for insurance purposes. Several remote sensing platforms and sensors are currently used for the manual detection of building damages. However, there is an overall interest in the use of automated methods to perform this task, regardless of the used platform. Owing to its synoptic coverage and predictable availability, satellite imagery is currently used as input for the identification of building damages by the International Charter, as well as the Copernicus Emergency Management Service for the production of damage grading and reference maps. Recently proposed methods to perform image classification of building damages rely on convolutional neural networks (CNN). These are usually trained with only satellite image samples in a binary classification problem, however the number of samples derived from these images is often limited, affecting the quality of the classification results. The use of up/down-sampling image samples during the training of a CNN, has demonstrated to improve several image recognition tasks in remote sensing. However, it is currently unclear if this multi resolution information can also be captured from images with different spatial resolutions like satellite and airborne imagery (from both manned and unmanned platforms). In this paper, a CNN framework using residual connections and dilated convolutions is used considering both manned and unmanned aerial image samples to perform the satellite image classification of building damages. Three network configurations, trained with multi-resolution image samples are compared against two benchmark networks where only satellite image samples are used. Combining feature maps generated from airborne and satellite image samples, and refining these using only the satellite image samples, improved nearly 4 % the overall satellite image

Satellite To Satellite Doppler Tracking (SSDT) for mapping of the Earth's gravity field

NASA Technical Reports Server (NTRS)

Colombo, G.; Gaposchkin, E. M.; Grossi, M.

1981-01-01

Two SSDT schemes were evaluated: a standard, low-low, SSDT configuration, which both satellites are in basically the same low altitude nearly circular orbit and the pair is characterized by small angular separation; and a more general configuration in which the two satellites are in arbitrary orbits, so that different configurations can be comparatively analyed. The standard low-low SSDT configuration is capable of recovering 1 deg X 1 deg surface anomalies with a strength as low as 1 milligal, located on the projected satellite path, when observing from a height as large as 300 km. The Colombo scheme provides an important complement of SSDT observations, inasmuch as it is sensitive to radial velocity components, while keeping at the same performance level both measuring sensitivity and measurement resolution.

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.

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

NASA Technical Reports Server (NTRS)

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

1975-01-01

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

Licensing of future mobile satellite systems

NASA Technical Reports Server (NTRS)

Lepkowski, Ronald J.

1990-01-01

The regulatory process for licensing mobile satellite systems is complex and can require many years to complete. This process involves frequency allocations, national licensing, and frequency coordination. The regulatory process that resulted in the establishment of the radiodetermination satellite service (RDSS) between 1983 and 1987 is described. In contrast, each of these steps in the licensing of the mobile satellite service (MSS) is taking a significantly longer period of time to complete.

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…

Recovery of refractivity profiles and pressure and temperature distributions in the lower atmosphere from satellite-to-satellite radio occultation data

NASA Technical Reports Server (NTRS)

Murray, C. W., Jr.

1977-01-01

The feasibility of recovering parameters from one-way range rate between two earth orbiting spacecraft during occultation of the tracking signal by the earth's lower atmosphere. The tracking data is inverted by an integral transformation (Abel transform) to obtain a vertical refractivity profile above the point of closest approach of the ray connecting the satellites. Pressure and temperature distributions can be obtained from values of dry refractivity using the hydrostatic equation and perfect gas law. Two methods are investigated for recovering pressure and temperature parameters. Results show that recovery is much more sensitive to satellite velocity errors than to satellite position errors. An error analysis is performed. An example is given demonstrating recovery of parameters from radio occultation data obtained during satellite-to-satellite tracking of Nimbus 6 by the ATS 6 satellite.

Satellite data-relay activities in Arizona

USGS Publications Warehouse

Boner, F.C.; Blee, J.W.; Shope, W.G.

1985-01-01

The U.S. Geological Survey (USGS) Arizona District collects data from automated streamflow stations for a wide variety of uses. Data from these stations are provided to Federal, State, and local agencies that have a responsibility to issue flood warnings; to generate forecasts of water availability; to monitor flow to insure compliance with treaties and other legal mandates; and to manage reservoirs for hydropower, flood abatement, and municipal and irrigation water supply. In the mid-1970's, the escalation of data collection costs and a need for more timely data led the Arizona District to examine alternatives for remote data acquisition. On the basis of successful data communications experiments with NASA 's Landsat satellite, an operational system for satellite-data relay was developed in 1976 using the National Oceanic and Atmospheric Administrations 's (NOAA) Geostationary Operational Environmental Satellite (GOES). A total of 62 data collection platforms (DCP's) was operated in 1983. Satellite telemetry operations are controlled at the remote data-collection stations by small battery-operated data collection platforms. The DCP 's periodically collect data from the sensors, store the data in computer memory, and at preset times transmit the data to the GOES satellite. The satellite retransmits the data to Earth where a ground-receive station transmits or transfers the data by land communications to the USGS computer in Reston, Virginia, for processing. The satellite relay transfers the data from sensor to computer in minutes; therefore, the data are available to users on a near real-time basis. (Author 's abstract)

14/12-GHz-band satellite communication services

NASA Astrophysics Data System (ADS)

Hayashi, Kunihiro; Nagaki, Kiyoaki; Mori, Yasuo

1990-01-01

Three new systems for integrated TV-relay services have been developed: Satellite Video Comunication Service (SVCS) and Satellite Digital Communication Service (SDCS), with Japan's 14/12-GHz-band commercial communication satellites. These systems have been in commercial use since May 1989. Usually SVCS and SDCS have been provided using Ka-band (30/20 GHz-band) of CS-2 and Cs-3. This paper provides an overview of the design, the performance, and the systems of the new 14/12-GHz-band satellite communication services.

Global trends in satellite-based emergency mapping

USGS Publications Warehouse

Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

2016-01-01

Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective.

Spectral Measurements of Geosynchronous Satellites During Glint Season

DTIC Science & Technology

2015-10-18

mechanical structures. 1. INTRODUCTION Man-made satellites serve a plethora of purposes from navigation to remote sensing. Geostationary orbits...in effect causing these satellites to appear fixed above the same point on earth. These geostationary satellites (GEOs) facilitate communications... Geostationary satellites are used for communication and navigation, among other purposes as mentioned above. By observing and characterizing the

Autonomous sensor-based dual-arm satellite grappling

NASA Technical Reports Server (NTRS)

Wilcox, Brian; Tso, Kam; Litwin, Todd; Hayati, Samad; Bon, Bruce

1989-01-01

Dual-arm satellite grappling involves the integration of technologies developed in the Sensing and Perception (S&P) Subsystem for object acquisition and tracking, and the Manipulator Control and Mechanization (MCM) Subsystem for dual-arm control. S&P acquires and tracks the position, orientation, velocity, and angular velocity of a slowly spinning satellite, and sends tracking data to the MCM subsystem. MCM grapples the satellite and brings it to rest, controlling the arms so that no excessive forces or torques are exerted on the satellite or arms. A 350-pound satellite mockup which can spin freely on a gimbal for several minutes, closely simulating the dynamics of a real satellite is demonstrated. The satellite mockup is fitted with a panel under which may be mounted various elements such as line replacement modules and electrical connectors that will be used to demonstrate servicing tasks once the satellite is docked. The subsystems are housed in three MicroVAX II microcomputers. The hardware of the S&P Subsystem includes CCD cameras, video digitizers, frame buffers, IMFEX (a custom pipelined video processor), a time-code generator with millisecond precision, and a MicroVAX II computer. Its software is written in Pascal and is based on a locally written vision software library. The hardware of the MCM Subsystem includes PUMA 560 robot arms, Lord force/torque sensors, two MicroVAX II computers, and unimation pneumatic parallel grippers. Its software is written in C, and is based on a robot language called RCCL. The two subsystems are described and test results on the grappling of the satellite mockup with rotational rates of up to 2 rpm are provided.

Leonardo-BRDF: A New Generation Satellite Constellation

NASA Technical Reports Server (NTRS)

Esper, Jaime; Neeck, Steven; Wiscombe, Warren; Ryschkewitsch, Michael; Andary, J. (Technical Monitor)

2000-01-01

Instantaneous net radiation flux at the top of the atmosphere is one of the primary drivers of climate and global change. Since the dawn of the satellite era, great efforts and expense have gone into measuring this flux from single satellites and even (for a several-year period) from a constellation of three satellites called ERBE. However, the reflected solar flux is an angular and spectral integral over the so-called "BRDF" or Bidirectional Reflectance Distribution Function, which is the angular distribution of reflected solar radiation for each solar zenith angle and each wavelength. Previous radiation flux satellites could not measure instantaneous BRDF, so scientists have had to fall back on models or composites. Because their range of observed solar zenith angles was very limited due to sunsynchronous orbits, the resultant flux maps are too inaccurate to see the dynamics of radiation flux or to reliably correlate it with specific phenomena (hurricanes, biomass fires, urban pollution, dust outbreaks, etc.). Accuracy only becomes acceptable after monthly averaging, but this washes out almost all cause-and-effect information, further exacerbated by the lack of spectral resolution. Leonardo-BRDF is a satellite system designed to measure the instantaneous spectral BRDF using a formation of highly coordinated satellites, all pointing at the same Earth targets at the same time. It will allow scientists for the first time to assess the radiative forcing of climate due to specific phenomena, which is bound to be important in the ongoing debate about global warming and what is causing it. The formation is composed of two satellite types having, as instrument payloads, single highly-integrated miniature imaging spectrometers or radiometers. Two nearby "keystone" satellites anchor the formation and fly in static orbits. They employ wide field of view imaging spectrometers that are extremely light and compact. The keystone satellites are identical and can operate in

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…

Analysis of laser jamming to satellite-based detector

NASA Astrophysics Data System (ADS)

Wang, Si-wen; Guo, Li-hong; Guo, Ru-hai

2009-07-01

The reconnaissance satellite, communication satellite and navigation satellite used in the military applications have played more and more important role in the advanced technique wars and already become the significant support and aid system for military actions. With the development of all kinds of satellites, anti-satellite laser weapons emerge as the times require. The experiments and analyses of laser disturbing CCD (charge coupled detector) in near ground have been studied by many research groups, but their results are not suitable to the case that using laser disturbs the satellite-based detector. Because the distance between the satellite-based detector and the ground is very large, it is difficult to damage it directly. However the optical receive system of satellite detector has large optical gain, so laser disturbing satellite detector is possible. In order to determine its feasibility, the theoretical analyses and experimental study are carried out in the paper. Firstly, the influence factors of laser disturbing satellite detector are analyzed in detail, which including laser power density on the surface of the detector after long distance transmission, and laser power density threshold for disturbing etc. These factors are not only induced by the satellite orbit, but dependence on the following parameters: laser average power in the ground, laser beam quality, tracing and aiming precision and atmospheric transmission. A calculation model is developed by considering all factors which then the power density entering into the detector can be calculated. Secondly, the laser disturbing experiment is performed by using LD (laser diode) with the wavelength 808 nm disturbing CCD 5 kilometer away, which the disturbing threshold value is obtained as 3.55×10-4mW/cm2 that coincides with other researcher's results. Finally, using the theoretical model, the energy density of laser on the photosensitive surface of MSTI-3 satellite detector is estimated as about 100m

Tracking and data relay satellite system (TDRSS) capabilities

NASA Astrophysics Data System (ADS)

Spearing, R. E.

1985-10-01

The Tracking and Data Relay Satellite System (TDRSS) is the latest implementation to tracking and data acquisition network for near-earth orbiting satellite support designed to meet the requirements of the current and projected (to the year 2000) satellite user community. The TDRSS consists of a space segment (SS) and a ground segment (GS) that fit within NASA's Space Network (SN) complex controlled at the Goddard Space Flight Center. The SS currently employs a single satellite, TDRS-1, with two additional satellites to be deployed in January 1986 and July 1986. The GS contains the communications and equipment required to manage the three TDR satellites and to transmit and receive information to and from TDRSS user satellites. Diagrams and tables illustrating the TDRSS signal characteristics, the situation of TDRSS within the SN, the SN operations and element interrelationships, as well as future plans for new missions are included.

Tracking and data relay satellite system (TDRSS) capabilities

NASA Technical Reports Server (NTRS)

Spearing, R. E.

1985-01-01

The Tracking and Data Relay Satellite System (TDRSS) is the latest implementation to tracking and data acquisition network for near-earth orbiting satellite support designed to meet the requirements of the current and projected (to the year 2000) satellite user community. The TDRSS consists of a space segment (SS) and a ground segment (GS) that fit within NASA's Space Network (SN) complex controlled at the Goddard Space Flight Center. The SS currently employs a single satellite, TDRS-1, with two additional satellites to be deployed in January 1986 and July 1986. The GS contains the communications and equipment required to manage the three TDR satellites and to transmit and receive information to and from TDRSS user satellites. Diagrams and tables illustrating the TDRSS signal characteristics, the situation of TDRSS within the SN, the SN operations and element interrelationships, as well as future plans for new missions are included.

The use of satellites in non-goestationary orbits for unloading geostationary communication satellite traffic peaks. Volume 2: Technical report

NASA Technical Reports Server (NTRS)

Price, K.; Turner, A.; Nguyen, T.; Doong, W.; Weyandt, C.

1987-01-01

The part of the geostationary (GEO) orbital arc used for United States domestic fixed, communications service is rapidly becoming filled with satellites. One of the factors currently limiting its utilization is that communications satellites must be designed to have sufficient capacity to handle peak traffic leads, and thus are under utilized most of the time. A solution is to use satellites in suitable non-geostationary orbits to unload the traffic peaks. Three different designs for a non-geostationary orbit communications satellite system are presented for the 1995 time frame. The economic performance is analyzed and compared with geostationary satellites for two classes of service, trunking and customer premise service. The result is that the larger payload of the non-geostationary satellite offsets the burdens of increased complexity and worse radiation environment to give improved economic performance. Depending on ground terminal configuration, the improved economic performance of the space segment may be offset by increased ground terminal expenses.

Thermospheric density estimation from SLR observations of LEO satellites - A case study with the ANDE-Pollux satellite

NASA Astrophysics Data System (ADS)

Blossfeld, M.; Schmidt, M.; Erdogan, E.

2016-12-01

The thermospheric neutral density plays a crucial role within the equation of motion of Earth orbiting objects since drag, lift or side forces are one of the largest non-gravitational perturbations acting on the satellite. Precise Orbit Determination (POD) methods can be used to estimate thermospheric density variations from measured orbit determinations. One method which provides highly accurate measurements of the satellite position is Satellite Laser Ranging (SLR). Within the POD process, scaling factors are estimated frequently. These scaling factors can be either used for the scaling of the so called satellite-specific drag (ballistic) coefficients or the integrated thermospheric neutral density. We present a method for analytically model the drag coefficient based on a couple of physical assumptions and key parameters. In this paper, we investigate the possibility to use SLR observations to the very low Earth orbiting satellite ANDE-Pollux (approximately at 350km altitude) to determine scaling factors for different a priori thermospheric density models. We perform a POD for ANDE-Pollux covering 49 days between August 2009 and September 2009 which means the time span containing the largest number of observations during the short lifetime of the satellite. Finally, we compare the obtained scaled thermospheric densities w.r.t. each other

On the life and death of satellite haloes

NASA Astrophysics Data System (ADS)

Taffoni, Giuliano; Mayer, Lucio; Colpi, Monica; Governato, Fabio

2003-05-01

We study the evolution of dark matter satellites orbiting inside more massive haloes using semi-analytical tools coupled with high-resolution N-body simulations. We select initial satellite sizes, masses, orbital energies, and eccentricities as predicted by hierarchical models of structure formation. Both the satellite (of initial mass Ms,0) and the main halo (of mass Mh) are described by a Navarro, Frenk & White density profile with various concentrations. We explore the interplay between dynamic friction and tidal mass loss/evaporation in determining the final fate of the satellite. We provide a user-friendly expression for the dynamic friction time-scale τdf,live and for the disruption time for a live (i.e. mass-losing) satellite. This can be easily implemented into existing semi-analytical models of galaxy formation improving considerably the way they describe the evolution of satellites. Massive satellites (Ms,0 > 0.1Mh) starting from typical cosmological orbits sink rapidly (irrespective of the initial circularity) toward the centre of the main halo where they merge after a time τdf,rig, as if they were rigid. Satellites of intermediate mass (0.01Mh < Ms,0 < 0.1Mh) suffer severe tidal mass losses as dynamic friction reduces their pericentre distance. In this case, mass loss increases substantially their decay time with respect to a rigid satellite. The final fate depends on the concentration of the satellite, cs, relative to that of the main halo, ch. Only in the unlikely case where cs/ch<~ 1 are satellites disrupted. In this mass range, τdf,live gives a measure of the merging time. Among the satellites whose orbits decay significantly, those that survive must have been moving preferentially on more circular orbits since the beginning as dynamical friction does not induce circularization. Lighter satellites (Ms,0 < 0.01Mh) do not suffer significant orbital decay and tidal mass loss stabilizes the orbit even further. Their orbits should map those at the

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.

NOAASIS Gateway - NOAA Satellite Information System (NOAASIS); Office of

Science.gov Websites

Satellite and Product Operations » DOC » NOAA » NESDIS » NOAASIS NOAA Satellite Information System NOAASIS Gateway The NOAA Satellite Information System provides essential information for satellite direct readout station operators and users of NOAA environmental satellite data. While the emphasis is on

System and Apparatus for Deploying a Satellite

NASA Technical Reports Server (NTRS)

Santos, Luis H. (Inventor); Hudeck, John D. (Inventor)

2016-01-01

A frictionless satellite constraint system is provided. The constraint system includes at least one clamp bar configured to restrain a satellite within the constraint system in an axial direction. The constraint system also includes a plurality of pins configured to restrain the satellite within the constraint system in a lateral direction.

State Geography Using NOAA Polar-Orbiting Satellites.

ERIC Educational Resources Information Center

Stadler, Stephen J.

1985-01-01

NOAA polar-orbiting satellites have the capability of providing views of entire states. This article describes the characteristics of data from these satellites, indicates their advantages and disadvantages, and shows how the satellite data can be used in a statewide representation of physical geography for students at the introductory level. (RM)

IMS/Satellite Situation Center report. Predicted orbit plots for IMP-H-1976. [Explorer 47 satellite

NASA Technical Reports Server (NTRS)

1975-01-01

Predicted orbit plots are shown in three projections. The time period covered by each set of projections is 12 days 6 hours, corresponding approximately to the period of IMP-H satellite. The three coordinate systems used are the Geocentric Solar Ecliptic system (GSE), the Geocentric Solar Magnetospheric system (GSM), and the Solar Magnetic system (SM). For each of the three projections, time ticks and codes are given on the satellite trajectories. The codes are interpreted in the table at the base of each plot. Time is given in the table as year/day/decimal hour. The total time covered by each plot is shown at the bottom of each table. An additional variable is given in the table for each time tick. For the GSM and SM projection this variable is the geocentric distance to the satellite in earth radii, and for the GSE projection the variable is satellite ecliptic latitude in degrees.

Influence of tides in viscoelastic bodies of planet and satellite on the satellite's orbital motion

NASA Astrophysics Data System (ADS)

Emelyanov, N. V.

2018-06-01

The problem of influence of tidal friction in both planetary and satellite bodies upon satellite's orbital motion is considered. Using the differential equations in satellite's rectangular planetocentric coordinates, the differential equations describing the changes in semimajor axis and eccentricity are derived. The equations in rectangular coordinates were taken from earlier works on the problem. The calcultations carried out for a number of test examples prove that the averaged solutions of equations in coordinates and precise solutions of averaged equations in the Keplerian elements are identical. For the problem of tides raised on planet's body, it was found that, if satellite's mean motion n is equal to 11/18 Ω, where Ω is the planet's angular rotation rate, the orbital eccentricity does not change. This conclusion is in agreement with the results of other authors. It was also found that there is essential discrepancy between the equations in the elements obtained in this paper and analogous equations published by earlier researchers.

Low Earth Orbit satellite/terrestrial mobile service compatibility

NASA Technical Reports Server (NTRS)

Sheriff, Ray E.; Gardiner, John G.

1993-01-01

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

Space industrialization - Education. [via communication satellites

NASA Technical Reports Server (NTRS)

Joels, K. M.

1978-01-01

The components of an educational system based on, and perhaps enhanced by, space industrialization communications technology are considered. Satellite technology has introduced a synoptic distribution system for various transmittable educational media. The cost of communications satellite distribution for educational programming has been high. It has, therefore, been proposed to utilize Space Shuttle related technology and Large Space Structures (LSS) to construct a system with a quantum advancement in communication capability and a quantum reduction in user cost. LSS for communications purposes have three basic advantages for both developed and emerging nations, including the ability to distribute signals over wide geographic areas, the reduced cost of satellite communications systems versus installation of land based systems, and the ability of a communication satellite system to create instant educational networks.

Laser Communication Experiments with Artemis Satellite

NASA Astrophysics Data System (ADS)

Kuzkov, Sergii; Sodnik, Zoran; Kuzkov, Volodymyr

2013-10-01

In November 2001, the European Space Agency (ESA) established the world-first inter-satellite laser communication link between the geostationary ARTEMIS satellite and the low Earth orbiting (LEO) SPOT-4 Earth observation satellite, demonstrating data rates of 50 Mbps. In 2006, the Japanese Space Agency launched the KIRARI (OICETS) LEO satellite with a compatible laser communication terminal and bidirectional laser communication links (50 Mbps and 2 Mbps) were successfully realized between KIRARI and ARTEMIS. ESA is now developing the European Data Relay Satellite (EDRS) system, which will use laser communication technology to transmit data between the Sentinel 1 and 2 satellites in LEO to two geostationary satellites (EDRS-A and EDRS-C) at data rates of 1.8 Gbps. As the data handling capabilities of state-of-the-art telecommunication satellites in GEO increase so is the demand for the feeder-link bandwidth to be transmitted from ground. This is why there is an increasing interest in developing high bandwidth ground-to-space laser communication systems working through atmosphere. In 2002, the Main Astronomical Observatory (MAO) started the development of its own laser communication system for its 0.7m AZT-2 telescope, located in Kyiv, Ukraine. The work was supported by the National Space Agency of Ukraine and by ESA. MAO developed a highly accurate computerized tracking system for AZT-2 telescope and a compact laser communication package called LACES (Laser Atmosphere and Communication Experiments with Satellites). The LACES instrument includes a camera of the pointing and tracking subsystems, a receiver module, a laser transmitter module, a tip/tilt atmospheric turbulence compensation subsystem, a bit error rate tester module and other optical and electronic components. The principal subsystems are mounted on a platform, which is located at the Cassegrain focus of the AZT-2 telescope. All systems were tested with the laser communication payload on-board ARTEMIS and

Validation of Satellite Retrieved Land Surface Variables

NASA Technical Reports Server (NTRS)

Lakshmi, Venkataraman; Susskind, Joel

1999-01-01

The effective use of satellite observations of the land surface is limited by the lack of high spatial resolution ground data sets for validation of satellite products. Recent large scale field experiments include FIFE, HAPEX-Sahel and BOREAS which provide us with data sets that have large spatial coverage and long time coverage. It is the objective of this paper to characterize the difference between the satellite estimates and the ground observations. This study and others along similar lines will help us in utilization of satellite retrieved data in large scale modeling studies.

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.

The Archimedes satellite system

NASA Astrophysics Data System (ADS)

Taylor, Stuart C.; Shurvinton, William D.

1992-03-01

Archimedes is a satellite system conceived by the European Space Agency (ESA) to effectively serve the European market for Mobile Radio Services (MRS). This paper describes the requirements and technical design of the Archimedes satellite system. The underlying assumptions and trade-offs behind the design are detailed and the design is compared and contrasted against alternative design solutions, both technically and economically. A path forward for the development of the system is indicated.

Autonomous Navigation of a Satellite Cluster

DTIC Science & Technology

1990-12-01

satellite’s velocity are determined by the Clohessy - Wiltshire equations I (these equations will be introduced in the next section) and take the form: (8:80...transition matrix, is based upon the Clohessy - Wiltshire equations of motion. These equations describe "the relative motion of two satellites when one is in a...discovery warranted a re-examination of the solutions to the Clohessy - Wiltshire equations. If the solutions for satellite #1 and #2 are subtracted

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.

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.

Review of West Germany's DFS satellite telecommunications program

NASA Astrophysics Data System (ADS)

1984-01-01

The purchase of telecommunication satellites by the German postal system is announced. Three satellites are under construction. One satellite is to take over actual operational functions, the second is to be parked in orbit, and the third is stored on the ground for emergencies. The services provided are discussed. The satellites are to enhance the cable and radio relay networks already in use.

Satellite power system salvage and disposal alternatives

NASA Technical Reports Server (NTRS)

1980-01-01

A wide range of salvage options for the SPS satellite, ranging from use in and beyond geosynchronous orbit to use in low Earth orbit in return and use on Earth are presented. The satellite can be used intact to provide power for various purposes, it can be cannibalized or it can be melted down to supply materials for space or ground based products. The use of SPS beyond its nominal lifetime provides value that can be deducted from the SPS capital investment cost. The present value of the salvage value of the SPS satellites, referenced to the system initial operation data, is on the order of five to ten percent of its on-orbit capital cost. (Given a 30 year satellite lifetime and a four percent discount rate, the theoretical maximum salvage value is 30.8 percent of the capital cost.) The SPS demonstration satellite is available some 30 years earlier than the first full scale SPS satellite and has a salvage value on the order of 80 percent of its on-orbit capital cost. In the event that it becomes desirable to dispose of either the demonstration of full scale SPS satellite, a number of disposal options is presented for which intact disposal costs are less than one percent of capital costs.

AMOS Galaxy 15 Satellite Observations and Analysis

NASA Astrophysics Data System (ADS)

Hall, D.

2011-09-01

In early April 2010, the Galaxy 15 geosynchronous satellite experienced an on-orbit anomaly. Even though the satellite's transmitters and articulating solar panel were still functioning, ground controllers lost the ability to command and maneuver the satellite. With its orbital position no longer maintained, Galaxy 15 began to drift eastward. This forced several other satellites to make collision avoidance maneuvers during the following months. Soon after the initial anomaly, Galaxy 15's operators predicted that the satellite’s reaction wheels would eventually become saturated, causing a loss of both spacecraft attitude and proper sunward orientation of the solar panels. This "off-pointing" event finally occurred in late December, ultimately leading to a depletion of Galaxy 15's batteries. This near-death experience had a fortunate side effect, however, in that it forced the satellite’s command unit to reboot and once again be able to both receive and execute ground commands. The satellite operators have since recovered control of the satellite. AMOS conducted non-resolved photometric observations of Galaxy 15 before, during and after these events. Similar observations were conducted of Galaxy 12, the nearly-identical replacement satellite. This presentation presents and discusses these temporal brightness signatures in detail, comparing the changing patterns in the observations to the known sequence of events.

Man-Made Moons: Satellite Communications for Schools.

ERIC Educational Resources Information Center

Grayson, Lawrence P.; And Others

In an effort to prepare teachers for the coming changes in education caused by the rapidly developing communication satellite technology, this monograph offers a non-technical background to this new development. It begins by explaining the importance of such satellites and offers a layman's guide to the technology of satellite systems. It reviews…

47 CFR 76.127 - Satellite sports blackout.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 4 2014-10-01 2014-10-01 false Satellite sports blackout. 76.127 Section 76... Sports Blackout § 76.127 Satellite sports blackout. (a) Upon the request of the holder of the broadcast rights to a sports event, or its agent, no satellite carrier shall retransmit to subscribers within the...

47 CFR 76.127 - Satellite sports blackout.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 4 2013-10-01 2013-10-01 false Satellite sports blackout. 76.127 Section 76... Sports Blackout § 76.127 Satellite sports blackout. (a) Upon the request of the holder of the broadcast rights to a sports event, or its agent, no satellite carrier shall retransmit to subscribers within the...

47 CFR 76.127 - Satellite sports blackout.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 4 2012-10-01 2012-10-01 false Satellite sports blackout. 76.127 Section 76... Sports Blackout § 76.127 Satellite sports blackout. (a) Upon the request of the holder of the broadcast rights to a sports event, or its agent, no satellite carrier shall retransmit to subscribers within the...

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…

47 CFR 76.127 - Satellite sports blackout.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Satellite sports blackout. 76.127 Section 76... Sports Blackout § 76.127 Satellite sports blackout. (a) Upon the request of the holder of the broadcast rights to a sports event, or its agent, no satellite carrier shall retransmit to subscribers within the...

47 CFR 76.127 - Satellite sports blackout.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Satellite sports blackout. 76.127 Section 76... Sports Blackout § 76.127 Satellite sports blackout. (a) Upon the request of the holder of the broadcast rights to a sports event, or its agent, no satellite carrier shall retransmit to subscribers within the...

Teamwork Reasoning and Multi-Satellite Missions

NASA Technical Reports Server (NTRS)

Marsella, Stacy C.; Plaunt, Christian (Technical Monitor)

2002-01-01

NASA is rapidly moving towards the use of spatially distributed multiple satellites operating in near Earth orbit and Deep Space. Effective operation of such multi-satellite constellations raises many key research issues. In particular, the satellites will be required to cooperate with each other as a team that must achieve common objectives with a high degree of autonomy from ground based operations. The multi-agent research community has made considerable progress in investigating the challenges of realizing such teamwork. In this report, we discuss some of the teamwork issues that will be faced by multi-satellite operations. The basis of the discussion is a particular proposed mission, the Magnetospheric MultiScale mission to explore Earth's magnetosphere. We describe this mission and then consider how multi-agent technologies might be applied in the design and operation of these missions. We consider the potential benefits of these technologies as well as the research challenges that will be raised in applying them to NASA multi-satellite missions. We conclude with some recommendations for future work.

Web Transfer Over Satellites Being Improved

NASA Technical Reports Server (NTRS)

Allman, Mark

1999-01-01

Extensive research conducted by NASA Lewis Research Center's Satellite Networks and Architectures Branch and the Ohio University has demonstrated performance improvements in World Wide Web transfers over satellite-based networks. The use of a new version of the Hypertext Transfer Protocol (HTTP) reduced the time required to load web pages over a single Transmission Control Protocol (TCP) connection traversing a satellite channel. However, an older technique of simultaneously making multiple requests of a given server has been shown to provide even faster transfer time. Unfortunately, the use of multiple simultaneous requests has been shown to be harmful to the network in general. Therefore, we are developing new mechanisms for the HTTP protocol which may allow a single request at any given time to perform as well as, or better than, multiple simultaneous requests. In the course of study, we also demonstrated that the time for web pages to load is at least as short via a satellite link as it is via a standard 28.8-kbps dialup modem channel. This demonstrates that satellites are a viable means of accessing the Internet.

Potential markets for advanced satellite communications

NASA Astrophysics Data System (ADS)

Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

1993-09-01

This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

Potential markets for advanced satellite communications

NASA Technical Reports Server (NTRS)

Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

1993-01-01

This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

CCD astrometric observations of Saturnian satellites

NASA Astrophysics Data System (ADS)

Veiga, C. H.; Vieira Martins, R.; Vienne, A.; Thuillot, W.; Arlot, J.-E.

2003-03-01

Astrometric positions of the first eight largest Saturnian satellites and the Lagrangian satellites Helene, Telesto and Calypso are presented from 493 CCD frames taken at the oppositions in 1995 through 1999. The images were obtained over 27 nights. Observed positions are compared with the calculated ones from Vienne and Duriez TASS 1.7 for the large satellites and from JPL positions for the Lagrangian satellites. The rms is about 0farcs 12 for the former but 0farcs 20 for Iapetus and 0farcs 28 for Hyperion. For the Lagrangian satellites it is about 0farcs 21 for Helene, 2farcs 02 for Telesto and 0farcs 60 for Calypso. The catalog (Full Table \\ref{tab4}) is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/400/1095 Based on observations made at Laboratório Nacional de Astrofísica/MCT-Itajubá-Brazil.

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.

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.

Satellite-Relayed Intercontinental Quantum Network.

PubMed

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-19

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ∼kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

Satellite-Relayed Intercontinental Quantum Network

NASA Astrophysics Data System (ADS)

Liao, Sheng-Kai; Cai, Wen-Qi; Handsteiner, Johannes; Liu, Bo; Yin, Juan; Zhang, Liang; Rauch, Dominik; Fink, Matthias; Ren, Ji-Gang; Liu, Wei-Yue; Li, Yang; Shen, Qi; Cao, Yuan; Li, Feng-Zhi; Wang, Jian-Feng; Huang, Yong-Mei; Deng, Lei; Xi, Tao; Ma, Lu; Hu, Tai; Li, Li; Liu, Nai-Le; Koidl, Franz; Wang, Peiyuan; Chen, Yu-Ao; Wang, Xiang-Bin; Steindorfer, Michael; Kirchner, Georg; Lu, Chao-Yang; Shu, Rong; Ursin, Rupert; Scheidl, Thomas; Peng, Cheng-Zhi; Wang, Jian-Yu; Zeilinger, Anton; Pan, Jian-Wei

2018-01-01

We perform decoy-state quantum key distribution between a low-Earth-orbit satellite and multiple ground stations located in Xinglong, Nanshan, and Graz, which establish satellite-to-ground secure keys with ˜kHz rate per passage of the satellite Micius over a ground station. The satellite thus establishes a secure key between itself and, say, Xinglong, and another key between itself and, say, Graz. Then, upon request from the ground command, Micius acts as a trusted relay. It performs bitwise exclusive or operations between the two keys and relays the result to one of the ground stations. That way, a secret key is created between China and Europe at locations separated by 7600 km on Earth. These keys are then used for intercontinental quantum-secured communication. This was, on the one hand, the transmission of images in a one-time pad configuration from China to Austria as well as from Austria to China. Also, a video conference was performed between the Austrian Academy of Sciences and the Chinese Academy of Sciences, which also included a 280 km optical ground connection between Xinglong and Beijing. Our work clearly confirms the Micius satellite as a robust platform for quantum key distribution with different ground stations on Earth, and points towards an efficient solution for an ultralong-distance global quantum network.

Global trends in satellite-based emergency mapping.

PubMed

Voigt, Stefan; Giulio-Tonolo, Fabio; Lyons, Josh; Kučera, Jan; Jones, Brenda; Schneiderhan, Tobias; Platzeck, Gabriel; Kaku, Kazuya; Hazarika, Manzul Kumar; Czaran, Lorant; Li, Suju; Pedersen, Wendi; James, Godstime Kadiri; Proy, Catherine; Muthike, Denis Macharia; Bequignon, Jerome; Guha-Sapir, Debarati

2016-07-15

Over the past 15 years, scientists and disaster responders have increasingly used satellite-based Earth observations for global rapid assessment of disaster situations. We review global trends in satellite rapid response and emergency mapping from 2000 to 2014, analyzing more than 1000 incidents in which satellite monitoring was used for assessing major disaster situations. We provide a synthesis of spatial patterns and temporal trends in global satellite emergency mapping efforts and show that satellite-based emergency mapping is most intensively deployed in Asia and Europe and follows well the geographic, physical, and temporal distributions of global natural disasters. We present an outlook on the future use of Earth observation technology for disaster response and mitigation by putting past and current developments into context and perspective. Copyright © 2016, American Association for the Advancement of Science.

Applications of Geostationary Satellite Data to Aviation

NASA Astrophysics Data System (ADS)

Ellrod, Gary P.; Pryor, Kenneth

2018-03-01

Weather is by far the most important factor in air traffic delays in the United States' National Airspace System (NAS) according to the Federal Aviation Administration (FAA). Geostationary satellites have been an effective tool for the monitoring of meteorological conditions that affect aviation operations since the launch of the first Synchronous Meteorological Satellite (SMS) in the United States in 1974. This paper will review the global use of geostationary satellites in support of aviation weather since their inception, with an emphasis on the latest generation of satellites, such as Geostationary Operational Environmental Satellite (GOES)-R (16) with its Advanced Baseline Imager (ABI) and Geostationary Lightning Mapper (GLM). Specific applications discussed in this paper include monitoring of convective storms and their associated hazards, fog and low stratus, turbulence, volcanic hazards, and aircraft icing.

Model of load distribution for earth observation satellite

NASA Astrophysics Data System (ADS)

Tu, Shumin; Du, Min; Li, Wei

2017-03-01

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

The role of satellite cells in muscle hypertrophy.

PubMed

Blaauw, Bert; Reggiani, Carlo

2014-02-01

The role of satellite cells in muscle hypertrophy has long been a debated issue. In the late 1980s it was shown that proteins remain close to the myonucleus responsible for its synthesis, giving rise to the idea of a nuclear domain. This, together with the observation that during various models of muscle hypertrophy there is an activation of the muscle stem cells, i.e. satellite cells, lead to the idea that satellite cell activation is required for muscle hypertrophy. Thus, satellite cells are not only responsible for muscle repair and regeneration, but also for hypertrophic growth. Further support for this line of thinking was obtained after studies showing that irradiation of skeletal muscle, and therefore elimination of all satellite cells, completely prevented overload-induced hypertrophy. Recently however, using different transgenic approaches, it has become clear that muscle hypertrophy can occur without a contribution of satellite cells, even though in most situations of muscle hypertrophy satellite cells are activated. In this review we will discuss the contribution of satellite cells, and other muscle-resident stem cells, to muscle hypertrophy both in mice as well as in humans.

Satellite ATM Networks: Architectures and Guidelines Developed

NASA Technical Reports Server (NTRS)

vonDeak, Thomas C.; Yegendu, Ferit

1999-01-01

An important element of satellite-supported asynchronous transfer mode (ATM) networking will involve support for the routing and rerouting of active connections. Work published under the auspices of the Telecommunications Industry Association (http://www.tiaonline.org), describes basic architectures and routing protocol issues for satellite ATM (SATATM) networks. The architectures and issues identified will serve as a basis for further development of technical specifications for these SATATM networks. Three ATM network architectures for bent pipe satellites and three ATM network architectures for satellites with onboard ATM switches were developed. The architectures differ from one another in terms of required level of mobility, supported data rates, supported terrestrial interfaces, and onboard processing and switching requirements. The documentation addresses low-, middle-, and geosynchronous-Earth-orbit satellite configurations. The satellite environment may require real-time routing to support the mobility of end devices and nodes of the ATM network itself. This requires the network to be able to reroute active circuits in real time. In addition to supporting mobility, rerouting can also be used to (1) optimize network routing, (2) respond to changing quality-of-service requirements, and (3) provide a fault tolerance mechanism. Traffic management and control functions are necessary in ATM to ensure that the quality-of-service requirements associated with each connection are not violated and also to provide flow and congestion control functions. Functions related to traffic management were identified and described. Most of these traffic management functions will be supported by on-ground ATM switches, but in a hybrid terrestrial-satellite ATM network, some of the traffic management functions may have to be supported by the onboard satellite ATM switch. Future work is planned to examine the tradeoffs of placing traffic management functions onboard a satellite as

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

One Web Satellites Ground Breaking

NASA Image and Video Library

2017-03-16

Brian Holz, CEO of OneWeb Satellites, speaks during the groundbreaking ceremony at Kennedy's Exploration Park for OneWeb. The company, in partnership with Airbus, is building a 150,000-square-foot factory to manufacture satellites that will connect all areas of the world to the Internet wirelessly. Photo credit: NASA/Kim Shiflett

Geosynchronous earth orbit/low earth orbit space object inspection and debris disposal: A preliminary analysis using a carrier satellite with deployable small satellites

NASA Astrophysics Data System (ADS)

Crockett, Derick

Detailed observations of geosynchronous satellites from earth are very limited. To better inspect these high altitude satellites, the use of small, refuelable satellites is proposed. The small satellites are stationed on a carrier platform in an orbit near the population of geosynchronous satellites. A carrier platform equipped with deployable, refuelable SmallSats is a viable option to inspect geosynchronous satellites. The propellant requirement to transfer to a targeted geosynchronous satellite, perform a proximity inspection mission, and transfer back to the carrier platform in a nearby orbit is determined. Convex optimization and traditional optimization techniques are explored, determining minimum propellant trajectories. Propellant is measured by the total required change in velocity, delta-v. The trajectories were modeled in a relative reference frame using the Clohessy-Wiltshire equations. Mass estimations for the carrier platform and the SmallSat were determined by using the rocket equation. The mass estimates were compared to the mass of a single, non-refuelable satellite performing the same geosynchronous satellite inspection missions. From the minimum delta-v trajectories and the mass analysis, it is determined that using refuelable SmallSats and a carrier platform in a nearby orbit can be more efficient than using a single non-refuelable satellite to perform multiple geosynchronous satellite inspections.

Recommended satellite imagery capabilities for disaster management

NASA Technical Reports Server (NTRS)

Richards, P. B.; Robinove, C. J.; Wiesnet, D. R.; Salomonson, V. V.; Maxwell, M. S.

1982-01-01

This study explores the role that satellite imaging systems might play in obtaining information needed in the management of natural and manmade disasters. Information requirements which might conceivably be met by satellite were identified for over twenty disasters. These requirements covered pre-disaster mitigation and preparedness activities, disaster response activities, and post-disaster recovery activities. The essential imaging satellite characteristics needed to meet most of the information requirements are 30 meter (or finer) spatial resolution, frequency of observations of one week or less, data delivery times of one day or less, and stereo, synoptic all-weather coverage of large areas in the visible, near infrared, thermal infrared and microwave bands. Of the current and planned satellite systems investigated for possible application to disaster management, Landsat-D and SPOT appear to have the greatest potential during disaster mitigation and preparedness activities, but all satellites studied have serious deficiencies during response and recovery activities. Several strawman concepts are presented for a satellite system optimized to support all disaster management activities.

Morphology of Dwarf Galaxies in Isolated Satellite Systems

NASA Astrophysics Data System (ADS)

Ann, Hong Bae

2017-08-01

The environmental dependence of the morphology of dwarf galaxies in isolated satellite systems is analyzed to understand the origin of the dwarf galaxy morphology using the visually classified morphological types of 5836 local galaxies with z ≲ 0.01. We consider six sub-types of dwarf galaxies, dS0, dE, dE_{bc}, dSph, dE_{blue}, and dI, of which the first four sub-types are considered as early-type and the last two as late-type. The environmental parameters we consider are the projected distance from the host galaxy (r_{p}), local and global background densities, and the host morphology. The spatial distributions of dwarf satellites of early-type galaxies are much different from those of dwarf satellites of late-type galaxies, suggesting the host morphology combined with r_{p} plays a decisive role on the morphology of the dwarf satellite galaxies. The local and global background densities play no significant role on the morphology of dwarfs in the satellite systems hosted by early-type galaxies. However, in the satellite system hosted by late-type galaxies, the global background densities of dE and dSph satellites are significantly different from those of dE_{bc}, dE_{blue}, and dI satellites. The blue-cored dwarf satellites (dE_{bc}) of early-type galaxies are likely to be located at r_{p} > 0.3 Mpc to keep their cold gas from the ram pressure stripping by the hot corona of early-type galaxies. The spatial distribution of dE_{bc} satellites of early-type galaxies and their global background densities suggest that their cold gas is intergalactic material accreted before they fall into the satellite systems.

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

RADIATION DAMAGE TO SATELLITE ELECTRONIC SYSTEMS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rogers, S.C.

The radiation sensitivity of satellite electronic systems was examined in order to determine the limitations they place on satellite life. The effects of radiation on components are briefly reviewed. Methods are presented and illustrated for determining the minimum radiation level at which circuit failure could occur. The effects of shielding on the radiation belt levels are discussed. It is shown that the effects of space radiation on satellite circuits, in general, can be made negligible by using good design practices. (M.C.G.)

The Earth Synchronous Satellite Carrier Rocket,

DTIC Science & Technology

1984-01-26

FOREIGN TECHNOLOGY DIVISION 0 - THE EARTH SYNCHRONOUS SATELLITE CARRIER ROCKET jJ by Zhou Yiyun ’% AR 2 1984 Approved for public-release; 84 03 01 071...I - FTD-ID(RS)T-1787-83 EDITED TRANSLATION FTD-IDCRS)T-1787-83 26 January 1984 MICROFICHE NR: FTD-84-C-000094 THE EARTH SYNCHRONOUS SATELLITE CARRIER...quality copy available. / THE EARTH SYNCHRONOUS SATELLITE CARRIER ROCKET by Zhou Yiyun Last September, the fight for the champion of the Women’s World

The Galilean Satellites

NASA Image and Video Library

1997-11-18

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. http://photojournal.jpl.nasa.gov/catalog/PIA00601

New Solar Cells to Boost Satellite Power

Science.gov Websites

New Solar Cells to Boost Satellite Power For more information contact: George Douglas (303) 275 much as doubled, each satellite and its services can be more economical and offer a greater return to satellite customers. The new cells will also have a longer useful life. Because of their construction they

Study of EVA operations associated with satellite services

NASA Technical Reports Server (NTRS)

Nash, J. O.; Wilde, R. D.

1982-01-01

Extravehicular mobility unit (EMU) factors associated with satellite servicing activities are identified and the EMU improvements necessary to enhance satellite servicing operations are outlined. Areas of EMU capabilities, equipment and structural interfaces, time lines, EMU modifications for satellite servicing, environmental hazards, and crew training are vital to manned Eva/satellite services and as such are detailed. Evaluation of EMU capabilities indicates that the EMU can be used in performing near term, basic satellite servicing tasks; however, satellite servicing is greatly enhanced by incorporating key modifications into the EMU. The servicing missions involved in contamination sensitive payload repair are illustrated. EVA procedures and equipment can be standardized, reducing both crew training time and in orbit operations time. By standardizing and coordinating procedures, mission cumulative time lines fall well within the EMU capability.

Spacecraft (Mobile Satellite) configuration design study

NASA Technical Reports Server (NTRS)

1985-01-01

The relative costs to procure and operate a two-satellite mobile satellite system designed to operate either in the UHF band of the L Band, and with several antenna diameter options in each frequency band was investigated. As configured, the size of the spacecraft is limited to the current RCA Series 4000 Geosynchronous Communications Spacecraft bus, which spans the range from 4000 to 5800 pounds in the transfer orbit. The Series 4000 bus forms the basis around which the Mobile Satellite transponder and associated antennas were appended. Although the resultant configuration has little outward resemblance to the present Series 4000 microwave communications spacecraft, the structure, attitude control, thermal, power, and command and control subsystems of the Series 4000 spacecraft are all adapted to support the Mobile Satellite mission.

Orbit determination for ISRO satellite missions

NASA Astrophysics Data System (ADS)

Rao, Ch. Sreehari; Sinha, S. K.

Indian Space Research Organisation (ISRO) has been successful in using the in-house developed orbit determination and prediction software for satellite missions of Bhaskara, Rohini and APPLE. Considering the requirements of satellite missions, software packages are developed, tested and their accuracies are assessed. Orbit determination packages developed are SOIP, for low earth orbits of Bhaskara and Rohini missions, ORIGIN and ODPM, for orbits related to all phases of geo-stationary missions and SEGNIP, for drift and geo-stationary orbits. Software is tested and qualified using tracking data of SIGNE-3, D5-B, OTS, SYMPHONIE satellites with the help of software available with CNES, ESA and DFVLR. The results match well with those available from these agencies. These packages have supported orbit determination successfully throughout the mission life for all ISRO satellite missions. Member-Secretary

Controlled tether extends satellite's orbital range

NASA Astrophysics Data System (ADS)

Wigotsky, V.

1984-06-01

A low orbit satellite tethered to the Space Shuttle Orbiter's cargo bay would be able to conduct upper atmosphere experiments without fear of orbit deterioration. NASA has in light of this initiated a Tethered Satellite System program aimed at the 1987 deployment of a 1,100-lb, 5 ft-diameter satellite to a distance of 6-12 miles from the Space Shuttle on a Kevlar tether. The distance of the fully developed system will be 62 miles, representing an altitude of 80 miles above the earth. Tether diameters under consideration are in the 0.065-0.1 inch range. The satellite control system will consist of a reel drive, a deployment boom, and a boom-mounted tether control, in order to vary tether tension during gravity gradient changes.

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.

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.

Satellite recovery - Attitude dynamics of the targets

NASA Technical Reports Server (NTRS)

Cochran, J. E., Jr.; Lahr, B. S.

1986-01-01

The problems of categorizing and modeling the attitude dynamics of uncontrolled artificial earth satellites which may be targets in recovery attempts are addressed. Methods of classification presented are based on satellite rotational kinetic energy, rotational angular momentum and orbit and on the type of control present prior to the benign failure of the control system. The use of approximate analytical solutions and 'exact' numerical solutions to the equations governing satellite attitude motions to predict uncontrolled attitude motion is considered. Analytical and numerical results are presented for the evolution of satellite attitude motions after active control termination.

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.

Use of Advanced Solar Cells for Commercial Communication Satellites

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Landis, Geoffrey A.

1995-01-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Use of advanced solar cells for commerical communication satellites

NASA Astrophysics Data System (ADS)

Landis, Geoffrey A.; Bailey, Sheila G.

1995-01-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar- and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because of the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from Low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Use of advanced solar cells for commercial communication satellites

NASA Astrophysics Data System (ADS)

Bailey, Sheila G.; Landis, Geoffrey A.

1995-03-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Mobile telephony through LEO satellites: To OBP or not

NASA Technical Reports Server (NTRS)

Monte, Paul A.; Louie, Ming; Wiedeman, R.

1991-01-01

GLOBALSTAR is a satellite-based mobile communications system that is interoperable with the current and future Public Land Mobile Network (PLMN) and Public Switched Telephone Network (PSTN). The selection of the transponder type, bent-pipe, or onboard processing (OBP), for GLOBALSTAR is based on many criteria, each of which is essential to the commercial and technological feasibility of GLOBALSTAR. The trade study that was done to determine the pros and cons of a bent-pipe transponder or an onboard processing transponder is described. The design of GLOBALSTAR's telecommunications system is a multi-variable cost optimization between the cost and complexity of individual satellites, the number of satellites required to provide coverage to the service areas, the cost of launching the satellites into their selected orbits, the ground segment cost, user equipment cost, satellite voice channel capacity, and other issues. Emphasis is on the cost and complexity of the individual satellites, specifically the transponder type and the impact of the transponder type on satellite and ground segment cost, satellite power and weight, and satellite voice channel capacity.

Characterization and isolation of highly purified porcine satellite cells

PubMed Central

Ding, Shijie; Wang, Fei; Liu, Yan; Li, Sheng; Zhou, Guanghong; Hu, Ping

2017-01-01

Pig is an important food source and an excellent system to model human diseases. Careful characterization of the swine skeletal muscle stem cells (satellite cells) will shed lights on generation of swine skeletal muscle disease model and efficient production of porcine meat for the food industry. Paired box protein 7 (Pax7) is a highly conserved transcription factor shared by satellite cells from various species. However, the sequence of Pax7 has not been characterized in pig. The lack of method to isolate highly purified satellite cells hinders the thorough characterization of the swine satellite cells. Here we found molecular markers for swine satellite cells and revealed that the porcine satellite cells were heterogeneous in various pieces of skeletal muscle. We further developed a method to isolate highly purified satellite cells directly from porcine muscles using fluorescence-activated cell sorting. We next characterized the proliferation and differentiation abilities of isolated satellite cells in vitro; and found that long-term culturing of satellite cells in vitro led to stemness loss. PMID:28417015

Mobile telephony through LEO satellites: To OBP or not

NASA Astrophysics Data System (ADS)

Monte, Paul A.; Louie, Ming; Wiedeman, R.

1991-11-01

GLOBALSTAR is a satellite-based mobile communications system that is interoperable with the current and future Public Land Mobile Network (PLMN) and Public Switched Telephone Network (PSTN). The selection of the transponder type, bent-pipe, or onboard processing (OBP), for GLOBALSTAR is based on many criteria, each of which is essential to the commercial and technological feasibility of GLOBALSTAR. The trade study that was done to determine the pros and cons of a bent-pipe transponder or an onboard processing transponder is described. The design of GLOBALSTAR's telecommunications system is a multi-variable cost optimization between the cost and complexity of individual satellites, the number of satellites required to provide coverage to the service areas, the cost of launching the satellites into their selected orbits, the ground segment cost, user equipment cost, satellite voice channel capacity, and other issues. Emphasis is on the cost and complexity of the individual satellites, specifically the transponder type and the impact of the transponder type on satellite and ground segment cost, satellite power and weight, and satellite voice channel capacity.

SCOPE : Future Formation-Flying Magnetospheric Satellite Mission

NASA Astrophysics Data System (ADS)

Saito, Yoshifumi

A formation flight satellite mission "SCOPE" is now under study aiming at launching in 2017. "SCOPE" stands for ‘cross Scale COupling in the Plasma universE'. The main purpose of this mission is to investigate the dynamic behaviors of plasma in the terrestrial magnetosphere that range over magnitudes of both temporal and spatial scales. The basic idea of the SCOPE mission is to distinguish temporal and spatial variations of physical processes by putting five formation flight spacecraft into the key regions of the Earth's magnetosphere. The formation consists of one large mother satellite and four small daughter satellites. Three of the four daughter satellites surround the mother satellite 3-dimensionally maintaining the mutual distances of variable ranges between 5 km and 5000 km. The fourth daughter satellite stays near the mother satellite with the distance between 5 km and 100 km. By this configuration, we can obtain both the macro-scale (1000 km - 5000 km) and micro-scale (¡ 100 km) information about the plasma disturbances at the same time. The launcher for SCOPE has been assumed to be M-V rocket (or its succession rocket) of JAXA. However, due to the termination of M-V rocket, we are now considering to use HIIA. The orbits of SCOPE satellites are all highly elliptical with its apogee 30Re from the Earth center. The inter-satellite link is used for telemetry/command operation as well as ranging to determine the relative orbits of the 5 satellites in small distances. The SCOPE mission is designed such that observational studies from the new perspective, the crossscale coupling, should be conducted. The orbit of the formation flight are designed such that the spacecraft will visit most of the key regions in the magnetosphere, including the bow shock, the magnetospheric boundary, the inner-magnetosphere, and the near-Earth magnetotail. The key issues for the realization of this mission are: (1) The need for high temporal resolution of electron measurements

47 CFR 74.643 - Interference to geostationary-satellites.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 47 Telecommunication 4 2014-10-01 2014-10-01 false Interference to geostationary-satellites. 74... Television Broadcast Auxiliary Stations § 74.643 Interference to geostationary-satellites. Applicants and... geostationary-satellites. [68 FR 12771, Mar. 17, 2003] ...

47 CFR 74.643 - Interference to geostationary-satellites.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 47 Telecommunication 4 2010-10-01 2010-10-01 false Interference to geostationary-satellites. 74... Television Broadcast Auxiliary Stations § 74.643 Interference to geostationary-satellites. Applicants and... geostationary-satellites. [68 FR 12771, Mar. 17, 2003] ...

47 CFR 74.643 - Interference to geostationary-satellites.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 47 Telecommunication 4 2013-10-01 2013-10-01 false Interference to geostationary-satellites. 74... Television Broadcast Auxiliary Stations § 74.643 Interference to geostationary-satellites. Applicants and... geostationary-satellites. [68 FR 12771, Mar. 17, 2003] ...

47 CFR 74.643 - Interference to geostationary-satellites.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 47 Telecommunication 4 2012-10-01 2012-10-01 false Interference to geostationary-satellites. 74... Television Broadcast Auxiliary Stations § 74.643 Interference to geostationary-satellites. Applicants and... geostationary-satellites. [68 FR 12771, Mar. 17, 2003] ...

47 CFR 74.643 - Interference to geostationary-satellites.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 4 2011-10-01 2011-10-01 false Interference to geostationary-satellites. 74... Television Broadcast Auxiliary Stations § 74.643 Interference to geostationary-satellites. Applicants and... geostationary-satellites. [68 FR 12771, Mar. 17, 2003] ...

Simulator design for advanced ISDN satellite design and experiments

NASA Technical Reports Server (NTRS)

Pepin, Gerald R.

1992-01-01

This simulation design task completion report documents the simulation techniques associated with the network models of both the Interim Service ISDN (integrated services digital network) Satellite (ISIS) and the Full Service ISDN Satellite (FSIS) architectures. The ISIS network model design represents satellite systems like the Advanced Communication 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 communication 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 events 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.

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.

Multi-CubeSat Deployment Strategies: How Different Satellite Deployment Schemes Affect Satellite Separation and Detection for Various Types of Constellations and Missions

DTIC Science & Technology

2016-03-24

2009.1 107 of the 158 satellites launched are operated by commercial entities.1 In early 2015, SpaceX and OneWeb each announced their plans to deploy...very large constellations of small satellites ( SpaceX – 4025, OneWeb – 648).1 Each of the OneWeb satellites is planned to weigh around 150 kg,12...while SpaceX expects their satellites to weigh several hundred kilograms each.13 Clearly, the growth in the use of small satellites is causing, and will

Sharing Resources In Mobile/Satellite Communications

NASA Technical Reports Server (NTRS)

Yan, Tsun-Yee; Sue, Miles K.

1992-01-01

Report presents preliminary theoretical analysis of several alternative schemes for allocation of satellite resource among terrestrial subscribers of landmobile/satellite communication system. Demand-access and random-access approaches under code-division and frequency-division concepts compared.

Comparison of satellite reflectance algorithms for estimating ...

EPA Pesticide Factsheets

We analyzed 10 established and 4 new satellite reflectance algorithms for estimating chlorophyll-a (Chl-a) in a temperate reservoir in southwest Ohio using coincident hyperspectral aircraft imagery and dense water truth collected within one hour of image acquisition to develop simple proxies for algal blooms and to facilitate portability between multispectral satellite imagers for regional algal bloom monitoring. Narrow band hyperspectral aircraft images were upscaled spectrally and spatially to simulate 5 current and near future satellite imaging systems. Established and new Chl-a algorithms were then applied to the synthetic satellite images and then compared to calibrated Chl-a water truth measurements collected from 44 sites within one hour of aircraft acquisition of the imagery. Masks based on the spatial resolution of the synthetic satellite imagery were then applied to eliminate mixed pixels including vegetated shorelines. Medium-resolution Landsat and finer resolution data were evaluated against 29 coincident water truth sites. Coarse-resolution MODIS and MERIS-like data were evaluated against 9 coincident water truth sites. Each synthetic satellite data set was then evaluated for the performance of a variety of spectrally appropriate algorithms with regard to the estimation of Chl-a concentrations against the water truth data set. The goal is to inform water resource decisions on the appropriate satellite data acquisition and processing for the es

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.

Satellite Imaging in the Study of Pennsylvania's Environmental Issues.

ERIC Educational Resources Information Center

Nous, Albert P.

This document focuses on using satellite images from space in the classroom. There are two types of environmental satellites routinely broadcasting: (1) Polar-Orbiting Operational Environmental Satellites (POES), and (2) Geostationary Operational Environmental Satellites (GOES). Imaging and visualization techniques provide students with a better…

Optical data communication for Earth observation satellite systems

NASA Astrophysics Data System (ADS)

Fischer, J.; Loecherbach, E.

1991-10-01

The current development status of optical communication engineering in comparison to the conventional microwave systems and the different configurations of the optical data communication for Earth observation satellite systems are described. An outlook to future optical communication satellite systems is given. During the last decade Earth observation became more and more important for the extension of the knowledge about our planet and the human influence on nature. Today pictures taken by satellites are used, for example, to discover mineral resources or to predict harvest, crops, climate, and environment variations and their influence on the population. A new and up to date application for Earth observation satellites can be the verification of disarmament arrangements and the control of crises areas. To solve these tasks a system of Earth observing satellites with sensors tailored to the envisaged mission is necessary. Besides these low Earth orbiting satellites, a global Earth observation system consists of at least two data relay satellites. The communication between the satellites will be established via Inter-Satellite Links (ISL) and Inter-Orbit Links (IOL). On these links, bitrates up to 1 Gbit/s must be taken into account. Due to the increasing scarcity of suitable frequencies, higher carrier frequencies must probably be considered, and possible interference with terrestrial radio relay systems are two main problems for a realization in microwave technique. One important step to tackle these problems is the use of optical frequencies for IOL's and ISL's.

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.

Results of Observations over Jupiter's Galilean Satellites

NASA Astrophysics Data System (ADS)

Chigladze, Revaz; Tateshvili, Maia

The work describes the polarization properties of the light reflected from the surfaces of Galileo Jupiter's satellites, with their physical characteristics studied based on their analysis. Europe turned out to have the most homogeneous, and Callisto has the least homogeneous. Time variations are the most typical to satellite Io what must be the result of the volcanic actions on the satellite surface.

Orbital design strategy for domestic communication satellite systems.

NASA Technical Reports Server (NTRS)

Ramji, S.; Sawitz, P.

1973-01-01

Review of some of the considerations pertinent to efficient orbit utilization in the design of domestic communications satellite systems. A strategy is developed to efficiently locate a heterogeneous system of satellites within the available arc and provide room for future growth. A practical design is illustrated, using a computer simulation model, for the placement of 25 satellites within 73% of the available arc employing frequency and polarization coordination techniques. A number of widely variable factors that influence satellite spacing are examined. These factors include such critical system elements as telephony and television interference noise limits, frequency plan coordination, polarization plan coordination, ground antenna diameter, signal protection ratio, and satellite station keeping.

Satellite Contributions to Global Change Studies

NASA Technical Reports Server (NTRS)

Parkinson, Claire L.

2009-01-01

By providing a global view with a level playing field (no region missed because of unfavorable surface conditions or political boundaries), satellites have made major contributions to improved monitoring and understanding of our constantly changing planet. The global view has allowed surprising realizations like the relative sparsity of lightning strikes over oceans and the large-scale undulations on the massive Antarctic ice sheet. It has allowed the tracking of all sorts of phenomena, including aerosols, both natural and anthropogenic, as they move with the atmospheric circulation and impact weather and human health. But probably nothing that the global view allows is more important in the long term than its provision. of unbiased data sets to address the issue of global change, considered by many to be among the most important issues facing humankind today. With satellites we can monitor atmospheric temperatures at all latitudes and longitudes, and obtain a global average that lessens the likelihood of becoming endlessly mired in the confusions brought about by the certainty of regional differences. With satellites we can monitor greenhouse gases such as CO2 not just above individual research stations but around the globe. With satellites we can monitor the polar sea ice covers, as we have done since the late 1970s, determining and quantifying the significant reduction in Arctic sea ice and the slight growth in Antarctic sea ice over that period, With satellites we can map the full extent and changes in the Antarctic stratospheric ozone depletions that were first identified from using a single ground station; and through satellite data we have witnessed from afar land surface changes brought about by humans both intentionally, as with wide-scale deforestation, and unintentionally, as with the decay of the Aral Sea. The satellite data are far from sufficient for all that we need in order to understand the global system and forecast its changes, as we also need

Small Cube Satellite Deploy

NASA Image and Video Library

2013-11-19

ISS038-E-003874 (19 Nov. 2013) --- Three nanosatellites, known as Cubesats, are deployed from a Small Satellite Orbital Deployer (SSOD) attached to the Kibo laboratory's robotic arm at 7:10 a.m. (EST) on Nov. 19, 2013. Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, monitored the satellite deployment while operating the Japanese robotic arm from inside Kibo. The Cubesats were delivered to the International Space Station Aug. 9, aboard Japan's fourth H-II Transfer Vehicle, Kounotori-4.

Satellite battery testing status

NASA Astrophysics Data System (ADS)

Haag, R.; Hall, S.

1986-09-01

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.

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.

Intra-enterprise telecommunication satellites

NASA Astrophysics Data System (ADS)

Henry, A. J.

1981-11-01

Information transfer in the mid 1980's is sketched. The use of geostationary satellites for internal requirements of businesses is an important factor in the growth of information transfer. Protection of transferred information is achieved through encryption. The companies which use satellites are those whose telecommunication costs are already significant; who have large computing capabilities including distributed data processing; who use national and international leased circuits; and whose establishments are dispersed. Uses include teleconferencing, voice and data transmission, and text and facsimile communication.

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.

Measuring Geosynchronous Satellites from Stellar Appulses with AO

DTIC Science & Technology

2014-09-01

These stars provided reference positions and magnitudes for the satellites . Overall, we demonstrate that we can time appulses of stars and geosynchronous...provided reference positions and magnitudes for the satellites . Overall, we demonstrate that we can time appulses of stars and geosynchronous satellites to...with 20 ms exposure times . When we returned to the third set of images, we found another satellite in the field and followed them together on the third

DIORAMA Model of Satellite Body Orientation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Werley, Kenneth Alan

2016-03-04

The DIORAMA GPS satellite platform orientation model is described. Satellites need to keep sensors pointed towards the earth and solar panels oriented to face the sun (when not in the earth’s shadow) while they orbit the earth.

CCRS Landcover Maps From Satellite Data

DOE Data Explorer

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.

Rotation histories of the natural satellites

NASA Technical Reports Server (NTRS)

Peale, S. J.

1977-01-01

Recent advances in the theory of rotation are combined with traditional approaches to study the rotational evolution of the 33 known natural satellites. A calculation similar to that reported by Burns and Safronov (1973) is applied to each satellite to obtain the characteristic time of decay of any wobble motion to smooth rotation about the principal axis of maximum moment of inertia. Stability criteria and capture probabilities are calculated for the 3/2 spin resonance. Results show that only the regular satellites and Iapetus, Hyperion, Triton, and the moon are tidally evolved. Of these, 13 have confirmed synchronous rotation periods; capture probabilities into the 3/2 resonance indicate that none of the remaining 10 should be captured in nonsynchronous, commensurate spin states. For the most part, the irregular satellites retain their original spins except for a relaxation to principal axis rotation. Tidal evolution of the obliquities of the satellites is evaluated in the framework of the generalization of Cassini's laws for the moon. Nearly resonant, forced librations in longitude of 4.8 and 0.5 deg are calculated on the basis of the observed shapes of Phobos and Deimos, respectively.

High accuracy satellite drag model (HASDM)

NASA Astrophysics Data System (ADS)

Storz, Mark F.; Bowman, Bruce R.; Branson, Major James I.; Casali, Stephen J.; Tobiska, W. Kent

The dominant error source in force models used to predict low-perigee satellite trajectories is atmospheric drag. Errors in operational thermospheric density models cause significant errors in predicted satellite positions, since these models do not account for dynamic changes in atmospheric drag for orbit predictions. The Air Force Space Battlelab's High Accuracy Satellite Drag Model (HASDM) estimates and predicts (out three days) a dynamically varying global density field. HASDM includes the Dynamic Calibration Atmosphere (DCA) algorithm that solves for the phases and amplitudes of the diurnal and semidiurnal variations of thermospheric density near real-time from the observed drag effects on a set of Low Earth Orbit (LEO) calibration satellites. The density correction is expressed as a function of latitude, local solar time and altitude. In HASDM, a time series prediction filter relates the extreme ultraviolet (EUV) energy index E10.7 and the geomagnetic storm index ap, to the DCA density correction parameters. The E10.7 index is generated by the SOLAR2000 model, the first full spectrum model of solar irradiance. The estimated and predicted density fields will be used operationally to significantly improve the accuracy of predicted trajectories for all low-perigee satellites.

Giant step for communication satellite technology

NASA Technical Reports Server (NTRS)

Lovell, R. R.

1984-01-01

NASA's communications program, which is concerned with advanced communications technology, reflects the need for operational communications satellite capacity beyond the capabilities of current technology and the unwillingness of private industry in the U.S. to undertake making the required long-range, high-risk technology advances. It is pointed out that current satellites will not satisfy the forecasted demand for additional capacity in the 1990s and beyond. Current technology exists primarily up to 18 GHz. Designing a communications satellite at each of the three major uplink/downlink frequency bands (C, Ku, and Ka, 6/4 GHz, 14/11 GHz, and 30/20 GHz, respectively) presents different program management and technical problems. Increasing frequency or power can be done only by intensive sustained research. This is the rationale for NASA to pursue the Advanced Communications Technology Satellite (ACTS) program.

Giant step for communication satellite technology

NASA Astrophysics Data System (ADS)

Lovell, R. R.

1984-03-01

NASA's communications program, which is concerned with advanced communications technology, reflects the need for operational communications satellite capacity beyond the capabilities of current technology and the unwillingness of private industry in the U.S. to undertake making the required long-range, high-risk technology advances. It is pointed out that current satellites will not satisfy the forecasted demand for additional capacity in the 1990s and beyond. Current technology exists primarily up to 18 GHz. Designing a communications satellite at each of the three major uplink/downlink frequency bands (C, Ku, and Ka, 6/4 GHz, 14/11 GHz, and 30/20 GHz, respectively) presents different program management and technical problems. Increasing frequency or power can be done only by intensive sustained research. This is the rationale for NASA to pursue the Advanced Communications Technology Satellite (ACTS) program.

Discovery of two new satellites of Pluto.

PubMed

Weaver, H A; Stern, S A; Mutchler, M J; Steffl, A J; Buie, M W; Merline, W J; Spencer, J R; Young, E F; Young, L A

2006-02-23

Pluto's first known satellite, Charon, was discovered in 1978. It has a diameter (approximately 1,200 km) about half that of Pluto, which makes it larger, relative to its primary, than any other moon in the Solar System. Previous searches for other satellites around Pluto have been unsuccessful, but they were not sensitive to objects less, similar150 km in diameter and there are no fundamental reasons why Pluto should not have more satellites. Here we report the discovery of two additional moons around Pluto, provisionally designated S/2005 P 1 (hereafter P1) and S/2005 P 2 (hereafter P2), which makes Pluto the first Kuiper belt object known to have multiple satellites. These new satellites are much smaller than Charon, with estimates of P1's diameter ranging from 60 km to 165 km, depending on the surface reflectivity; P2 is about 20 per cent smaller than P1. Although definitive orbits cannot be derived, both new satellites appear to be moving in circular orbits in the same orbital plane as Charon, with orbital periods of approximately 38 days (P1) and approximately 25 days (P2).

TV via satellite from AT&T

NASA Astrophysics Data System (ADS)

Kiely, J.

1982-04-01

AT&T's Satellite Television Service, which relays TV feeds by means of the Comstar domestic communications satellite system, is discussed. Advantages include the ability to provide multiple feeds of program and advertising material simultaneously to affiliates, which can help accommodate the trend toward greater program diversity, and the ability to distribute one signal to many points, making their use economically attractive. A proposed radio service from AT&T is also discussed, which could provide radio broadcasters and programmers with a high-quality, versatile means of transmitting radio programs via satellite.

Small satellites and space debris issues

NASA Astrophysics Data System (ADS)

Yakovlev, M.; Kulik, S.; Agapov, V.

2001-10-01

The objective of this report is the analysis of the tendencies in designing of small satellites (SS) and the effect of small satellites on space debris population. It is shown that SS to include nano- and pico-satellites should be considered as a particularly dangerous source of space debris when elaborating international standards and legal documents concerning the space debris problem, in particular "International Space Debris Mitigation Standard". These issues are in accordance with the IADC goals in its main activity areas and should be carefully considered within the IADC framework.

Terrestrial Observations from NOAA Operational Satellites.

PubMed

Yates, H; Strong, A; McGinnis, D; Tarpley, D

1986-01-31

Important applications to oceanography, hydrology, and agriculture have been developed from operational satellites of the National Oceanic and Atmospheric Administration and are currently expanding rapidly. Areas of interest involving the oceans include sea surface temperature, ocean currents, and ocean color. Satellites can monitor various hydrological phenomena, including regional and global snow cover, river and sea ice extent, and areas of global inundation. Agriculturally important quantities derived from operational satellite observations include precipitation, daily temperature extremes, canopy temperatures, insolation, and snow cover. This overview describes the current status of each area.

Gradio: Project proposal for satellite gradiometry

NASA Technical Reports Server (NTRS)

Balmino, G.; Barilier, F.; Bernard, A.; Bouzat, C.; Riviera, G.; Runavot, J.

1981-01-01

A gradiometric approach, rather than the more complicated satellite to satellite tracking, is proposed for studying anomalies in the gravitational fields of the Earth and, possibly, other telluric bodies. The first analyses of a gradiometer based on four of ONERA's CACTUS or SUPERCACTUS accelerometers are summarized. it is shown that the obstacles to achieving the required accuracy are not insuperable. The device will be carried in a 1000 kg lens shaped satellite in a heliosynchronous orbit 200 to 300 km in altitude. The first launching is planned for the end of 1987.

Satellite Networks: Architectures, Applications, and Technologies

NASA Technical Reports Server (NTRS)

Bhasin, Kul (Compiler)

1998-01-01

Since global satellite networks are moving to the forefront in enhancing the national and global information infrastructures due to communication satellites' unique networking characteristics, a workshop was organized to assess the progress made to date and chart the future. This workshop provided the forum to assess the current state-of-the-art, identify key issues, and highlight the emerging trends in the next-generation architectures, data protocol development, communication interoperability, and applications. Presentations on overview, state-of-the-art in research, development, deployment and applications and future trends on satellite networks are assembled.

NASA compendium of satellite communications programs

NASA Technical Reports Server (NTRS)

1975-01-01

A comprehensive review is given of worldwide satellite communication programs that range in time from the inception of satellite communications to mid-1974. Particular emphasis is placed on program results, including experiments conducted, communications system operational performance, and technology employed. The background for understanding these results is established through brief summaries of the program organization, system configuration, and satellite and ground terminal characteristics. Major consideration is given to the communications system aspects of each program, but general spacecraft technology and other experiments conducted as part of the same program are mentioned summarily.

ARTES: the future of satellite telecommunication

NASA Astrophysics Data System (ADS)

González-Blázquez, Angel; Detain, Dominique

2005-08-01

Throughout its 30-year existence, ESA has played a key role by providing telecommunications infrastructures that have allowed the in-orbit validation, qualification and demonstration of equipment, technology and services. In the past, this has been achieved through the provision of dedicated satellites like OTS, Marecs, Olympus and Artemis, as well as by the implementation of piggy-back payloads on other ESA or commercial satellites. Today, due to the importance of satellite telecommunications, ESA continues to support this sector mainly through its ARTES - Advanced Research in Telecommunications - Programme.

On-board processing for telecommunications satellites

NASA Technical Reports Server (NTRS)

Nuspl, P. P.; Dong, G.

1991-01-01

In this decade, communications satellite systems will probably face dramatic challenges from alternative transmission means. To balance and overcome such competition, and to prepare for new requirements, INTELSAT has developed several on-board processing techniques, including Satellite-Switched TDMA (SS-TDMA), Satellite-Switched FDMA (SS-FDMA), several Modulators/Demodulators (Modem), a Multicarrier Multiplexer and Demodulator MCDD), an International Business Service (IBS)/Intermediate Data Rate (IDR) BaseBand Processor (BBP), etc. Some proof-of-concept hardware and software were developed, and tested recently in the INTELSAT Technical Laboratories. These techniques and some test results are discussed.

NASA mobile satellite program

NASA Technical Reports Server (NTRS)

Knouse, G.; Weber, W.

1985-01-01

A three phase development program for ground and space segment technologies which will enhance and enable the second and third generation mobile satellite systems (MSS) is outlined. Phase 1, called the Mobile Satellite Experiment (MSAT-X), is directed toward the development of ground segment technology needed for future MSS generations. Technology validation and preoperational experiments with other government agencies will be carried out during the two year period following launch. The satellite channel capacity needed to carry out these experiments will be obtained from industry under a barter type agreement in exchange for NASA provided launch services. Phase 2 will develop and flight test the multibeam spacecraft antenna technology needed to obtain substantial frequency reuse for second generation commercial systems. Industry will provide the antenna, and NASA will fly it on the Shuttle and test it in orbit. Phase 3 is similar to Phase 2 but will develop an even larger multibeam antenna and test it on the space station.

NASA mobile satellite program

NASA Astrophysics Data System (ADS)

Knouse, G.; Weber, W.

1985-04-01

A three phase development program for ground and space segment technologies which will enhance and enable the second and third generation mobile satellite systems (MSS) is outlined. Phase 1, called the Mobile Satellite Experiment (MSAT-X), is directed toward the development of ground segment technology needed for future MSS generations. Technology validation and preoperational experiments with other government agencies will be carried out during the two year period following launch. The satellite channel capacity needed to carry out these experiments will be obtained from industry under a barter type agreement in exchange for NASA provided launch services. Phase 2 will develop and flight test the multibeam spacecraft antenna technology needed to obtain substantial frequency reuse for second generation commercial systems. Industry will provide the antenna, and NASA will fly it on the Shuttle and test it in orbit. Phase 3 is similar to Phase 2 but will develop an even larger multibeam antenna and test it on the space station.

Aeronautical and Maritime Satellite Technology Bibliography

DOT National Transportation Integrated Search

1976-03-01

Material used and generated over the past five years on the aeronautical and maritime satellite programs has been reviewed and organized in this report. Emphasis has been placed on advanced electronic technology and its application to the satellite s...

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.

Integration of mobile satellite and cellular systems

NASA Astrophysics Data System (ADS)

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

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.

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.

Transient response measurements on a satellite system

NASA Technical Reports Server (NTRS)

Nanevicz, J. E.; Adamo, R. C.

1977-01-01

A set of instruments designed to detect the occurance of electrical breakdown was flown on a synchronous-orbit satellite. The LeRC sensors were installed on cables inside the vehicle. Accordingly, they respond to signals coupled into the satellite wiring system. The SRI sensors were located on the exterior of the vehicle and detected the RF noise pulses associated with surface breakdowns. The results of the earlier SRI program are being used to design and develop a set of intrumentation suitable for inclusion as a general piggy-back package for the detection of the onset of satellite charging and breakdowns on synchronous orbit satellites.

Uranus Satellites

NASA Image and Video Library

1996-11-26

On Jan. 18, 1986, NASA Voyager 2 discoverd three Uranus satellites. All three lie outside the orbits of Uranus nine known rings, the outermost of which, the epsilon ring, is seen at upper right. http://photojournal.jpl.nasa.gov/catalog/PIA00368

A novel approach for simulating the optical misalignment caused by satellite platform vibration in the ground test of satellite optical communication systems.

PubMed

Wang, Qiang; Tan, Liying; Ma, Jing; Yu, Siyuan; Jiang, Yijun

2012-01-16

Satellite platform vibration causes the misalignment between incident direction of the beacon and optical axis of the satellite optical communication system, which also leads to the instability of the laser link and reduces the precision of the system. So how to simulate the satellite platform vibration is a very important work in the ground test of satellite optical communication systems. In general, a vibration device is used for simulating the satellite platform vibration, but the simulation effect is not ideal because of the limited randomness. An approach is reasonable, which uses a natural random process for simulating the satellite platform vibration. In this paper, we discuss feasibility of the concept that the effect of angle of arrival fluctuation is taken as an effective simulation of satellite platform vibration in the ground test of the satellite optical communication system. Spectrum characteristic of satellite platform vibration is introduced, referring to the model used by the European Space Agency (ESA) in the SILEX program and that given by National Aeronautics and Space Development Agency (NASDA) of Japan. Spectrum characteristic of angle of arrival fluctuation is analyzed based on the measured data from an 11.16km bi-directional free space laser transmission experiment. Spectrum characteristic of these two effects is compared. The results show that spectra of these two effects have similar variation trend with the variation of frequency and feasibility of the concept is proved by the comparison results. At last the procedure of this method is proposed, which uses the power spectra of angle of arrival fluctuation to simulate that of the satellite platform vibration. The new approach is good for the ground test of satellite optical communication systems.

Commercial observation satellites: broadening the sources of geospatial data

NASA Astrophysics Data System (ADS)

Baker, John C.; O'Connell, Kevin M.; Venzor, Jose A.