WorldWideScience

Sample records for technology satellite apogee

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

    Science.gov (United States)

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

    2016-09-01

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

  2. Satellite communication antenna technology

    Science.gov (United States)

    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.

  3. Communication satellite technology trends

    Science.gov (United States)

    Cuccia, Louis

    1986-01-01

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

  4. 国内外卫星用液体远地点发动机发展综述%Development of liquid apogee engine for satellite at home and abroad

    Institute of Scientific and Technical Information of China (English)

    周红玲; 姜文龙; 刘昌国

    2011-01-01

    综述了国内外卫星用液体远地点发动机的发展情况,阐述了国外几种典型远地点发动机和国内三代490 N发动机的主要技术特点和技术指标,对比分析了其产品性能并介绍了其产品的考核应用情况。自上世纪90年代以来,国内外在卫星用液体远地点发动机的研制中喷注器性能不断提高,推力室均采用了新型抗高温氧化材料,主要以铼/铱材料和C/SiC复合材料为主,最终实现了发动机真空比冲性能的不断提高。先进的液体远地点发动机采用高性能喷注器和新型抗高温氧化材料,其比冲性能指标已高达323 s以上。%The technology characteristics and development trend of liquid apogee engines for satellites at home and abroad are summarized in this paper.The performance specification and the application of the typical engines abroad and the 490 N engines of three generations made in China are introduced.Since 1990s,the performance of the injectors in liquid apogee engines for satellites has been increasingly improved,and all the thrusters have adopted new type high-temperature oxidation resistant materials such as iridium/rhenium and C/SiC composite materials.Benefiting from the modified injectors and new materials,the performance of the liquid apogee engine has been significantly improved,and its specific impulse is up to 323 s.

  5. Advanced Communications Technology Satellite (ACTS)

    Science.gov (United States)

    Gedney, Richard T.; Schertler, Ronald J.

    1989-01-01

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

  6. Advanced Communications Technology Satellite (ACTS)

    Science.gov (United States)

    Olmstead, Dean A.; Schertler, Ronald J.

    The benefits that will be offered by the NASA-sponsored communication spacecraft ACTS which is scheduled for launch in 1992 are described together with examples of demonstrations on proposed data, video, and voice applications supported by the advanced ACTS technologies. Compared to existing satellite service, the ACTS will provide lower cost, better service, greater convenience, and improved service reliability of telecommunications to customers around the world. In addition, the pioneering ACTS technology will provide many capabilities qualitatively different from those of current satellite systems, such as on-demand assignment, frequency reuse, and the flexible targeting of spot beams directly to the very-small-aperture terminals at customer premises.

  7. Research Supporting Satellite Communications Technology

    Science.gov (United States)

    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.

  8. Introduction to Satellite Communications Technology for NREN

    Science.gov (United States)

    Stone, Thom

    2004-01-01

    NREN requirements for development of seamless nomadic networks necessitates that NREN staff have a working knowledge of basic satellite technology. This paper addresses the components required for a satellite-based communications system, applications, technology trends, orbits, and spectrum, and hopefully will afford the reader an end-to-end picture of this important technology.

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

    Science.gov (United States)

    Hoder, Douglas; Bergamo, Marcos

    1996-01-01

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

  10. women Contrlbute to Satellite Technology

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    IN the early morning of August 14, 1992, at the Xichang satellite launching center, China Central Television Station was about to do a live, worldwide broadcast on the launching of an Australian communications satellite made by the United States. With the order of the commander, "Ignition," people could watch the white rocket rise, pierce the blue sky and race toward the space with a long flaming tail trailing behind it.

  11. TUBSAT-1, satellite technology for educational purposes

    Science.gov (United States)

    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.

  12. Broadband Satellite Technologies and Markets Assessed

    Science.gov (United States)

    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.

  13. An Educator's Guide to Communication Satellite Technology.

    Science.gov (United States)

    Polcyn, Kenneth A.

    Recent developments in the area of sophisticated communications technology present challenges to the imagination of every educator. This guide provides educational planners with an awareness and understanding of communication satellite technology, its current uses, and some of the tentative plans for educational experimentation. The first part…

  14. Soviet satellite communications science and technology

    Energy Technology Data Exchange (ETDEWEB)

    Birch, J.N.; Campanella, S.J.; Gordon, G.D.; McElroy, D.R.; Pritchard, W.L.; Stamminger, R.

    1991-08-01

    This is a report by six US scientists and engineers concerning the current state of the art and projections of future Soviet satellite communications technologies. The panel members are experts in satellite stabilization, spacecraft environments, space power generation, launch systems, spacecraft communications sciences and technologies, onboard processing, ground stations, and other technologies that impact communications. The panel assessed the Soviet ability to support high-data-rate space missions at 128 Mbps by evaluating current and projected Soviet satellite communications technologies. A variety of space missions were considered, including Earth-to-Earth communications via satellites in geostationary or highly elliptical orbits, those missions that require space-to-Earth communications via a direct path and those missions that require space-to-Earth communications via a relay satellite. Soviet satellite communications capability, in most cases, is 10 years behind that of the United States and other industrialized nations. However, based upon an analysis of communications links needed to support these missions using current Soviet capabilities, it is well within the current Soviet technology to support certain space missions outlined above at rates of 128 Mbps or higher, although published literature clearly shows that the Soviet Union has not exceeded 60 Mbps in its current space system. These analyses are necessary but not sufficient to determine mission data rates, and other technologies such as onboard processing and storage could limit the mission data rate well below that which could actually be supported via the communications links. Presently, the Soviet Union appears to be content with data rates in the low-Earth-orbit relay via geostationary mode of 12 Mbps. This limit is a direct result of power amplifier limits, spacecraft antenna size, and the utilization of K{sub u}-band frequencies. 91 refs., 16 figs., 15 tabs.

  15. Advanced Communication Technology Satellite (ACTS) multibeam antenna technology verification experiments

    Science.gov (United States)

    Acosta, Roberto J.; Larko, Jeffrey M.; Lagin, Alan R.

    1992-01-01

    The Advanced Communication Technology Satellite (ACTS) is a key to reaching NASA's goal of developing high-risk, advanced communications technology using multiple frequency bands to support the nation's future communication needs. Using the multiple, dynamic hopping spot beams, and advanced on board switching and processing systems, ACTS will open a new era in communications satellite technology. One of the key technologies to be validated as part of the ACTS program is the multibeam antenna with rapidly reconfigurable hopping and fixed spot beam to serve users equipped with small-aperature terminals within the coverage areas. The proposed antenna technology experiments are designed to evaluate in-orbit ACTS multibeam antenna performance (radiation pattern, gain, cross pol levels, etc.).

  16. System Design and Key Technologies of the GF-3 Satellite

    Directory of Open Access Journals (Sweden)

    ZHANG Qingjun

    2017-03-01

    Full Text Available GF-3 satellite, the first C band and multi-polarization SAR satellite in China, achieves breakthroughs in a number of core and key technologies. The satellite technology abides by the principle of “Demand Pulls, Technology Pushes”, forming a series of innovation point, and reaching or surpassing international level in main technical specification.

  17. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) and its successor, APOGEE-2

    Science.gov (United States)

    Majewski, S. R.; APOGEE Team; APOGEE-2 Team

    2016-09-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) of Sloan Digital Sky Survey III (SDSS-III) has produced a large catalog of high resolution ({R = 22 500}), high quality (S/N > 100), infrared (H-band) spectra for stars throughout all stellar populations of the Milky Way, including in regions veiled by significant dust opacity. APOGEE's half million spectra collected on > 163 000 unique stars, with time series information via repeat visits to each star, are being applied to numerous problems in stellar populations, Galactic astronomy, and stellar astrophysics. From among the early results of the APOGEE project - which span from measurements of Galactic dynamics, to multi-element chemical maps of the disk and bulge, new views of the interstellar medium, explorations of stellar companions, the chemistry of star clusters, and the discovery of rare stellar species - I highlight a few results that demonstrate APOGEE's unique ability to sample and characterize the Galactic disk and bulge. Plans are now under way for an even more ambitious successor to APOGEE: the six-year, dual-hemisphere APOGEE-2 project. Both phases of APOGEE feature a strong focus on targets having asteroseismological measurements from either Kepler or {CoRoT}, from which it is possible to derive relatively precise stellar ages. The combined APOGEE and APOGEE-2 databases of stellar chemistry, dynamics and ages constitute an unusually comprehensive, systematic and homogeneous resource for constraining models of Galactic evolution.

  18. The Communications Technology Satellite /CTS/ Program

    Science.gov (United States)

    Evans, W. M.; Davies, N. G.; Hawersaat, W. H.

    1976-01-01

    The purposes of the joint Canadian-U.S. Communications Technology Satellite (CTS) Program are (1) to conduct satellite communication systems experiments using the 12- and 14-GHz bands and low-cost transportable ground terminals, (2) to develop and flight test a power amplifier tube having a greater than 50% efficiency with a saturated power output of 200 W at 12 GHz, (3) to develop and flight test a lightweight extendible solar array with an initial power output greater than 1 kW, and (4) to develop and flight test a 3-axis stabilization system to maintain accurate antenna boresight positioning on a spacecraft with flexible appendages. Brief descriptions of these experiments and of the ground facilities are provided.

  19. Distance and extinction determination for APOGEE stars with Bayesian method

    CERN Document Server

    Wang, Jianling; Pan, Kaike; Chen, Bingqiu; Zhao, Yongheng; Wicker, James

    2016-01-01

    Using a Bayesian technology we derived distances and extinctions for over 100,000 red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey by taking into account spectroscopic constraints from the APOGEE stellar parameters and photometric constraints from 2MASS, as well as a prior knowledge on the Milky Way. Derived distances are compared with those from four other independent methods, the Hipparcos parallaxes, star clusters, APOGEE red clump stars, and asteroseismic distances from APOKASC (Rodrigues et al. 2014) and SAGA Catalogues (Casagrande et al. 2014). These comparisons covers four orders of magnitude in the distance scale from 0.02 kpc to 20 kpc. The results show that our distances agree very well with those from other methods: the mean relative difference between our Bayesian distances and those derived from other methods ranges from -4.2% to +3.6%, and the dispersion ranges from 15% to 25%. The extinctions toward all stars are also derived and compared wi...

  20. Emerging Technologies: Small Satellite and Associated TPED

    Science.gov (United States)

    Zitz, R.

    2014-09-01

    The 2010 National Space Policy directs the U.S. space community, comprised of the Department of Defense, Intelligence Community, Military Services and NASA to examine our nation's ability to conduct space-based ISR and communications even during a period of peer state and near peer state attacks intended to deny us our advantages we accrue from our use of space systems. DOD and the ICs past experience is largely one of building small numbers of extraordinarily capable and expensive (exquisite) satellites for communications and ISR. As potential adversaries continue to develop cyber-attack capabilities and have demonstrated an ability to kinetically attack spacecraft, the vulnerability of our architecture is now a serious concern. In addition, the sluggish U.S. economy, the draw down and pull back from a decade of combat operations, and other factors have combined to force a significant reduction in DOD and IC spending over the coming decade(s). Simultaneously, DOD and the IC have a growing awareness that the long lead times and long mission duration of the exquisite space assets can lead to fielding technologies that become obsolete and mission limiting. Some DOD and IC leaders are now examining alternative architectures to provide lower cost, flexible, more diverse and rapidly launchable space systems. Government leaders are considering commercially hosted payloads in geosynchronous orbits and smaller, lower cost, free flying government and commercial satellites in low earth orbits. Additional changes to the ground tasking, processing, exploitation and dissemination (TPED) systems would ensure small satellites have end-to-end mission capability and meet emerging needs such as ease of tasking, multi-INT processing, and more advanced distribution mechanisms (e.g., to users on the move). Today, a majority of agency leaders and their subordinate program managers remain convinced that only large, expensive systems can truly answer requirements and provide reliable

  1. The Advanced Communication Technology Satellite and ISDN

    Science.gov (United States)

    Lowry, Peter A.

    1996-01-01

    This paper depicts the Advanced Communication Technology Satellite (ACTS) system as a global central office switch. The ground portion of the system is the collection of earth stations or T1-VSAT's (T1 very small aperture terminals). The control software for the T1-VSAT's resides in a single CPU. The software consists of two modules, the modem manager and the call manager. The modem manager (MM) controls the RF modem portion of the T1-VSAT. It processes the orderwires from the satellite or from signaling generated by the call manager (CM). The CM controls the Recom Laboratories MSPs by receiving signaling messages from the stacked MSP shelves ro units and sending appropriate setup commands to them. There are two methods used to setup and process calls in the CM; first by dialing up a circuit using a standard telephone handset or, secondly by using an external processor connected to the CPU's second COM port, by sending and receiving signaling orderwires. It is the use of the external processor which permits the ISDN (Integrated Services Digital Network) Signaling Processor to implement ISDN calls. In August 1993, the initial testing of the ISDN Signaling Processor was carried out at ACTS System Test at Lockheed Marietta, Princeton, NJ using the spacecraft in its test configuration on the ground.

  2. The role of technology in influencing future civil communications satellites

    Science.gov (United States)

    Bagwell, James W.; Mahle, Christoph E.

    1990-01-01

    Technology, both as an enabler and as a driver of new and improved communication satellites, is discussed. A brief look at the beginnings and evolution of satellite communications is given to reveal the continuing influence of technology over the past 25 years. An assessment of the current state of the art which serves as a benchmark representing how far technology has come and as a basis for comparison for future possibilities is presented. A short tutorial on communications satellite basics is presented, followed by an assessment of technologies used for satellite antennas and signal amplification and routing. A discussion of future service requirements follows, and emerging technologies are identified along with possible improved communications capabilities that can result from them. The outlook for the role of technology for future communication satellites is summarized.

  3. Status of the Third Miniature Sensor Technology Integration Satellite Mission

    OpenAIRE

    Barnhart, David; Hurtz, Rick; McClelland, Jim; Cellarius, Mark; Meyers, AI

    1994-01-01

    The MSTI-3 satellite is the third in a series established to test, in realistic scenarios, miniature spacecraft and sensor technologies for missile detection and tracking on low-cost, low-earth orbit technology demonstration satellites. Cooperative demonstrations are planned to combine MSTI-provided target track file information, with interceptor technology tests, to fully demonstrate technologies associated with theater missile defense (TMO) targeting. The program is sponsored by the Ballist...

  4. Apogee system using the lithium and water reaction

    Energy Technology Data Exchange (ETDEWEB)

    Duchemin, O.; Poinsot, C. [Ecole Nationale Superieure des Ingenieurs des Etudes et Techniques d`Armement, 29 - Brest (France)

    1996-12-31

    We investigate the feasibility of an apogee engine using Lithium and water as a bi-liquid propellant for a 2-ton class geostationary satellite. The Lithium and water reaction is briefly described, and after a discussion on how the high mass fraction of condensed products yielded by the reaction is handled by the NASA-Lewis code, the specific impulse is computed. A water to Lithium ratio of 2.4 at a chamber pressure of 5 bar and at a temperature of 1800 K is proposed as a baseline, for vacuum specific impulse of 286 s with a nozzle area ratio of 300. The most relevant issues of engineering design are eventually addressed. (authors) 4 refs.

  5. Building technological capability within satellite programs in developing countries

    Science.gov (United States)

    Wood, Danielle; Weigel, Annalisa

    2011-12-01

    This paper explores the process of building technological capability in government-led satellite programs within developing countries. The key message is that these satellite programs can learn useful lessons from literature in the international development community. These lessons are relevant to emerging satellite programs that leverage international partnerships in order to establish local capability to design, build and operate satellites. Countries with such programs include Algeria, Nigeria, Turkey, Malaysia and the United Arab Emirates. The paper first provides background knowledge about space activity in developing countries, and then explores the nuances of the lessons coming from the international development literature. Developing countries are concerned with satellite technology because satellites provide useful services in the areas of earth observation, communication, navigation and science. Most developing countries access satellite services through indirect means such as sharing data with foreign organizations. More countries, however, are seeking opportunities to develop satellite technology locally. There are objective, technically driven motivations for developing countries to invest in satellite technology, despite rich debate on this topic. The paper provides a framework to understand technical motivations for investment in satellite services, hardware, expertise and infrastructure in both short and long term. If a country decides to pursue such investments they face a common set of strategic decisions at the levels of their satellite program, their national context and their international relationships. Analysis of past projects shows that countries have chosen diverse strategies to address these strategic decisions and grow in technological capability. What is similar about the historical examples is that many countries choose to leverage international partnerships as part of their growth process. There are also historical examples from

  6. Cultures in orbit: Satellite technologies, global media and local practice

    Science.gov (United States)

    Parks, Lisa Ann

    Since the launch of Sputnik in 1957, satellite technologies have had a profound impact upon cultures around the world. "Cultures in Orbit" examines these seemingly disembodied, distant relay machines in relation to situated social and cultural processes on earth. Drawing upon a range of materials including NASA and UNESCO documents, international satellite television broadcasts, satellite 'development' projects, documentary and science fiction films, remote sensing images, broadcast news footage, World Wide Web sites, and popular press articles I delineate and analyze a series of satellite mediascapes. "Cultures in Orbit" analyzes uses of satellites for live television relay, surveillance, archaeology and astronomy. The project examines such satellite media as the first live global satellite television program Our World, Elvis' Aloha from Hawaii concert, Aboriginal Australian satellite programs, and Star TV's Asian music videos. In addition, the project explores reconnaissance images of mass graves in Bosnia, archaeological satellite maps of Cleopatra's underwater palace in Egypt, and Hubble Space Telescope images. These case studies are linked by a theoretical discussion of the satellite's involvement in shifting definitions of time, space, vision, knowledge and history. The satellite fosters an aesthetic of global realism predicated on instantaneous transnational connections. It reorders linear chronologies by revealing traces of the ancient past on the earth's surface and by searching in deep space for the "edge of time." On earth, the satellite is used to modernize and develop "primitive" societies. Satellites have produced new electronic spaces of international exchange, but they also generate strategic maps that advance Western political and cultural hegemony. By technologizing human vision, the satellite also extends the epistemologies of the visible, the historical and the real. It allows us to see artifacts and activities on earth from new vantage points

  7. SATELLITE GRAVITY SURVEYING TECHNOLOGY AND RESEARCH OF EARTH'S GRAVITY FIELD

    Institute of Scientific and Technical Information of China (English)

    Ning Jinsheng

    2003-01-01

    This is a summarized paper. Two topics are discussed: Firstly, the concept, development and application of four kinds of satellite gravity surveying technology are introduced; Secondly, some problems of theory and method, which must be considered in the study of the Earth's gravity field based on satellite gravity data, are expounded.

  8. Satellite Networks: Architectures, Applications, and Technologies

    Science.gov (United States)

    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.

  9. Enabling Technology for Small Satellite Launch Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Access to space for Small Satellites is enabled by the use of excess launch capacity on existing launch vehicles. A range of sizes, form factors and masses of small...

  10. Enabling Technology for Small Satellite Launch Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Access to space for Small Satellites is enabled by the use of excess launch capacity on existing launch vehicles. A range of sizes, form factors and masses need to...

  11. Building Technological Capability within Satellite Programs in Developing Countries

    Science.gov (United States)

    Wood, Danielle Renee

    Global participation in space activity is growing as satellite technology matures and spreads. Countries in Africa, Asia and Latin America are creating or reinvigorating national satellite programs. These countries are building local capability in space through technological learning. They sometimes pursue this via collaborative satellite development projects with foreign firms that provide training. This phenomenon of collaborative satellite development projects is poorly understood by researchers of technological learning and technology transfer. The approach has potential to facilitate learning, but there are also challenges due to misaligned incentives and the tacit nature of the technology. Perspectives from literature on Technological Learning, Technology Transfer, Complex Product Systems and Product Delivery provide useful but incomplete insight for decision makers in such projects. This work seeks a deeper understanding of capability building through collaborative technology projects by conceiving of the projects as complex, socio-technical systems with architectures. The architecture of a system is the assignment of form to execute a function along a series of dimensions. The research questions explore the architecture of collaborative satellite projects, the nature of capability building during such projects, and the relationship between architecture and capability building. The research design uses inductive, exploratory case studies to investigate six collaborative satellite development projects. Data collection harnesses international field work driven by interviews, observation, and documents. The data analysis develops structured narratives, architectural comparison and capability building assessment. The architectural comparison reveals substantial variation in project implementation, especially in the areas of project initiation, technical specifications of the satellite, training approaches and the supplier selection process. The individual

  12. Multichannel demultiplexer/demodulator technologies for future satellite communication systems

    Science.gov (United States)

    Ivancic, William D.; Budinger, James M.; Staples, Edward J.; Abramovitz, Irwin; Courtois, Hector A.

    1992-01-01

    NASA-Lewis' Space Electronics Div. supports ongoing research in advanced satellite communication architectures, onboard processing, and technology development. Recent studies indicate that meshed VSAT (very small aperture terminal) satellite communication networks using FDMA (frequency division multiple access) uplinks and TDMA (time division multiplexed) downlinks are required to meet future communication needs. One of the critical advancements in such a satellite communication network is the multichannel demultiplexer/demodulator (MCDD). The progress is described which was made in MCDD development using either acousto-optical, optical, or digital technologies.

  13. Advanced Power Technology Development Activities for Small Satellite Applications

    Science.gov (United States)

    Piszczor, Michael F.; Landis, Geoffrey A.; Miller, Thomas B.; Taylor, Linda M.; Hernandez-Lugo, Dionne; Raffaelle, Ryne; Landi, Brian; Hubbard, Seth; Schauerman, Christopher; Ganter, Mathew; hide

    2017-01-01

    NASA Glenn Research Center (GRC) has a long history related to the development of advanced power technology for space applications. This expertise covers the breadth of energy generation (photovoltaics, thermal energy conversion, etc.), energy storage (batteries, fuel cell technology, etc.), power management and distribution, and power systems architecture and analysis. Such advanced technology is now being developed for small satellite and cubesat applications and could have a significant impact on the longevity and capabilities of these missions. A presentation during the Pre-Conference Workshop will focus on various advanced power technologies being developed and demonstrated by NASA, and their possible application within the small satellite community.

  14. Mobile satellite communications - Vehicle antenna technology update

    Science.gov (United States)

    Bell, D.; Naderi, F. M.

    1986-01-01

    This paper discusses options for vehicle antennas to be used in mobile satellite communications systems. Two types of antennas are identified. A non-steerable, azimuthally omnidirectional antenna with a modest gain of 3 to 5 dBi is suggested when a low cost is desired. Alternatively, mechanically or electronically steerable antennas with a higher gain of 10 to 12 dBi are suggested to alleviate power and spectrum scarcity associated with mobile satellite communications. For steerable antennas, both open-loop and closed-loop pointing schemes are discussed. Monopulse and sequential lobing are proposed for the mechanically steered and electronically steered antennas, respectively. This paper suggests a hybrid open-loop/closed-loop pointing technique as the best performer in the mobile satellite environment.

  15. NASA's mobile satellite communications program; ground and space segment technologies

    Science.gov (United States)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-10-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  16. NASA's mobile satellite communications program; ground and space segment technologies

    Science.gov (United States)

    Naderi, F.; Weber, W. J.; Knouse, G. H.

    1984-01-01

    This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

  17. Mobile satellite communications technology - A summary of NASA activities

    Science.gov (United States)

    Dutzi, E. J.; Knouse, G. H.

    1986-01-01

    Studies in recent years indicate that future high-capacity mobile satellite systems are viable only if certain high-risk enabling technologies are developed. Accordingly, NASA has structured an advanced technology development program aimed at efficient utilization of orbit, spectrum, and power. Over the last two years, studies have concentrated on developing concepts and identifying cost drivers and other issues associated with the major technical areas of emphasis: vehicle antennas, speech compression, bandwidth-efficient digital modems, network architecture, mobile satellite channel characterization, and selected space segment technology. The program is now entering the next phase - breadboarding, development, and field experimentation.

  18. Use of CDMA access technology in mobile satellite systems

    Science.gov (United States)

    Ramasastry, Jay; Wiedeman, Bob

    1995-01-01

    Use of Code Division Multiple Access (CDMA) technology in terrestrial wireless systems is fairly well understood. Similarly, design and operation of Power Control in a CDMA-based system in a terrestrial environment is also well established. Terrestrial multipath characteristics, and optimum design of the CDMA receiver to deal with multipath and fading conditions are reliably established. But the satellite environment is different. When the CDMA technology is adopted to the satellite environment, other design features need to be incorporated (for example; interleaving, open-loop and closed-loop power control design, diversity characteristics) to achieve comparable level of system performance. In fact, the GLOBALSTAR LEO/MSS system has incorporated all these features. Contrary to some published reports, CDMA retains the advantages in the satellite environment that are similar to those achieved in the terrestrial environment. This document gives a description of the CDMA waveform and other design features adopted for mobile satellite applications.

  19. Advanced Microelectronics Technologies for Future Small Satellite Systems

    Science.gov (United States)

    Alkalai, Leon

    1999-01-01

    Future small satellite systems for both Earth observation as well as deep-space exploration are greatly enabled by the technological advances in deep sub-micron microelectronics technologies. Whereas these technological advances are being fueled by the commercial (non-space) industries, more recently there has been an exciting new synergism evolving between the two otherwise disjointed markets. In other words, both the commercial and space industries are enabled by advances in low-power, highly integrated, miniaturized (low-volume), lightweight, and reliable real-time embedded systems. Recent announcements by commercial semiconductor manufacturers to introduce Silicon On Insulator (SOI) technology into their commercial product lines is driven by the need for high-performance low-power integrated devices. Moreover, SOI has been the technology of choice for many space semiconductor manufacturers where radiation requirements are critical. This technology has inherent radiation latch-up immunity built into the process, which makes it very attractive to space applications. In this paper, we describe the advanced microelectronics and avionics technologies under development by NASA's Deep Space Systems Technology Program (also known as X2000). These technologies are of significant benefit to both the commercial satellite as well as the deep-space and Earth orbiting science missions. Such a synergistic technology roadmap may truly enable quick turn-around, low-cost, and highly capable small satellite systems for both Earth observation as well as deep-space missions.

  20. Satellite systems for personal applications concepts and technology

    CERN Document Server

    Richharia, Madhavendra

    2010-01-01

    Presents the concepts, technology, and role of satellite systems in support of personal applications, such as mobile and broadband communications, navigation, television, radio and multimedia broadcasting, safety of life services, etc. This book presents a novel perspective on satellite systems, reflecting the modern personal technology context, and hence a focus on the individual as end-user. The book begins by outlining key generic concepts before discussing techniques adopted in particular application areas; next, it exemplifies these techniques through discussion of state-of-art c

  1. An overview of the Communications Technology Satellite (CTS) project

    Science.gov (United States)

    Rapp, W.; Ogden, D.; Wright, D.

    1982-01-01

    The Communications Technology Satellite (CTS) project is reviewed. A technical description of the CTS spacecraft and its cognate hardware and operations is included. A historical treatise of the CTS project is provided. Also presented is an overview of the CTS experiments and demonstrations conducted during the course of the project.

  2. Communications technology satellite output-tube design and development

    Science.gov (United States)

    Connolly, D. J.; Forman, R.; Jones, C. L.; Kosmahl, H.; Sharp, G. R.

    1977-01-01

    The design and development of a 200-watt-output, traveling-wave tube (TWT) for the Communications Technology Satellite (CTS) is discussed, with emphasis on the design evolution during the manufacturing phase of the development program. Possible further improvements to the tube design are identified.

  3. Technology status of HNF-based monopropellants for satellite propulsion

    NARCIS (Netherlands)

    Marée, A.G.M.; Moerel, J.L.P.A.; Weiland-Veltmans, W.H.M.; Wierkx, F.J.M.; Zevenbergen, J.

    2004-01-01

    This paper reports on significant technological progress made over the last few years in determining the feasibility of HNF-based monopropellants. An HNF-based monopropellant is an interesting alternative for hydrazine as monopropellant for satellite propulsion. New non-toxic monopropellants based o

  4. Technology status of HNF-based monopropellants for satellite propulsion

    NARCIS (Netherlands)

    Marée, A.G.M.; Moerel, J.L.P.A.; Weiland-Veltmans, W.H.M.; Wierkx, F.J.M.; Zevenbergen, J.

    2004-01-01

    This paper reports on significant technological progress made over the last few years in determining the feasibility of HNF-based monopropellants. An HNF-based monopropellant is an interesting alternative for hydrazine as monopropellant for satellite propulsion. New non-toxic monopropellants based o

  5. Satellite Technology Contribution to Water and Food Security

    Science.gov (United States)

    Brown, Molly E.

    2010-01-01

    This slide presentation reviews the issue of supplies of food, the relationship to food security, the ability of all people to attain sufficient food for an active and healthy life, and the ability to use satellite technology and remote sensing to assist with planning and act as an early warning system.

  6. Progress on the use of satellite technology for gravity exploration

    Directory of Open Access Journals (Sweden)

    Yanwei Ding

    2015-07-01

    Full Text Available In this paper, the technological progress on Chinese gravity exploration satellites is presented. Novel features such as ultra-stable structure, high accurate thermal control, drag-free and attitude control, micro-thrusters, aerodynamic configuration, the ability to perform micro-vibration analyses, microwave ranging system and mass center trimmer are described.

  7. Satellite remote-sensing technologies used in forest fire management

    Institute of Scientific and Technical Information of China (English)

    TIAN Xiao-rui; Douglas J. Mcrae; SHU Li-fu; WANG Ming-yu; LI Hong

    2005-01-01

    Satellite remote sensing has become a primary data source for fire danger rating prediction, fuel and fire mapping, fire monitoring, and fire ecology research. This paper summarizes the research achievements in these research fields, and discusses the future trend in the use of satellite remote-sensing techniques in wildfire management. Fuel-type maps from remote-sensing data can now be produced at spatial and temporal scales quite adequate for operational fire management applications. US National Oceanic and Atmospheric Administration (NOAA) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellites are being used for fire detection worldwide due to their high temporal resolution and ability to detect fires in remote regions. Results can be quickly presented on many Websites providing a valuable service readily available to fire agency. As cost-effective tools, satellite remote-sensing techniques play an important role in fire mapping. Improved remote-sensing techniques have the potential to date older fire scars and provide estimates of burn severity. Satellite remote sensing is well suited to assessing the extent of biomass burning, a prerequisite for estimating emissions at regional and global scales, which are needed for better understanding the effects of fire on climate change. The types of satellites used in fire research are also discussed in the paper. Suggestions on what remote-sensing efforts should be completed in China to modernize fire management technology in this country are given.

  8. A Fast, Affordable, Science and Technology SATellite (FASTSAT) and the Small Satellite Market Development Environment

    Science.gov (United States)

    Boudreaux, Mark; Montgomery, Edward; Cacas, Joseph

    2008-01-01

    The National Aeronautics and Space Administr ation at Marshall Space Flight Center and the National Space Science and Technology Center in Huntsville Alabama USA, are jointly developing a new class of science and technology mission small satellites. The Fast, Affordable, Science and Technology SATell ite (FASTSAT) was designed and developed using a new collaborative and best practices approach. The FASTSAT development, along with the new class of low cost vehicles currently being developed, would allow performance of 30 kg payload mass missions for a cost of less than 10 million US dollars.

  9. Assessment of a satellite power system and six alternative technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wolsko, T.; Whitfield, R.; Samsa, M.; Habegger, L.S.; Levine, E.; Tanzman, E.

    1981-04-01

    The satellite power system is assessed in comparison to six alternative technologies. The alternatives are: central-station terrestrial photovoltaic systems, conventional coal-fired power plants, coal-gasification/combined-cycle power plants, light water reactor power plants, liquid-metal fast-breeder reactors, and fusion. The comparison is made regarding issues of cost and performance, health and safety, environmental effects, resources, socio-economic factors, and insitutional issues. The criteria for selecting the issues and the alternative technologies are given, and the methodology of the comparison is discussed. Brief descriptions of each of the technologies considered are included. (LEW)

  10. The APOGEE Spectral Line List for H band Spectroscopy

    CERN Document Server

    Shetrone, Matthew; Lawler, James; Prieto, Carlos Allende; Johnson, Jennifer A; Smith, Verne; Cunha, Katia; Holtzman, Jon; Perez, Ana Garcia; Meszaros, Szabolcs; Sobeck, Jennifer; Zamora, Olga; Garcia-Hernandez, Anibal; Souto, Diogo; Chojnowski, Drew; Koesterke, Lars; Majewski, Steven

    2015-01-01

    We present the $H$ band spectral line lists adopted by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). The APOGEE line lists comprise astrophysical, theoretical, and laboratory sources from the literature, as well as newly evaluated astrophysical oscillator strengths and damping parameters. We discuss the construction of the APOGEE line list, which is one of the critical inputs for the APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP), and present three different versions that have been used at various stages of the project. The methodology for the newly calculated astrophysical line lists is reviewed. The largest of these three line lists contains 134457 molecular and atomic transitions. In addition to the format adopted to store the data, the line lists are available in MOOG, Synspec and Turbospectrum formats. We also present a list of $H$ band spectral features that are either poorly represented or completely missing in our line list. This list is based on the average...

  11. Baade's window and APOGEE. Metallicities, ages, and chemical abundances

    Science.gov (United States)

    Schultheis, M.; Rojas-Arriagada, A.; García Pérez, A. E.; Jönsson, H.; Hayden, M.; Nandakumar, G.; Cunha, K.; Allende Prieto, C.; Holtzman, J. A.; Beers, T. C.; Bizyaev, D.; Brinkmann, J.; Carrera, R.; Cohen, R. E.; Geisler, D.; Hearty, F. R.; Fernandez-Tricado, J. G.; Maraston, C.; Minnitti, D.; Nitschelm, C.; Roman-Lopes, A.; Schneider, D. P.; Tang, B.; Villanova, S.; Zasowski, G.; Majewski, S. R.

    2017-04-01

    Context. Baade's window (BW) is one of the most observed Galactic bulge fields in terms of chemical abundances. Owing to its low and homogeneous interstellar absorption it is considered the perfect calibration field for Galactic bulge studies. Aims: In the era of large spectroscopic surveys, calibration fields such as BW are necessary for cross calibrating the stellar parameters and individual abundances of the APOGEE survey. Methods: We use the APOGEE BW stars to derive the metallicity distribution function (MDF) and individual abundances for α- and iron-peak elements of the APOGEE ASPCAP pipeline (DR13), as well as the age distribution for stars in BW. Results: We determine the MDF of APOGEE stars in BW and find a remarkable agreement with that of the Gaia-ESO survey (GES). Both exhibit a clear bimodal distribution. We also find that the Mg-metallicity planes of the two surveys agree well, except for the metal-rich part ([Fe/H] > 0.1), where APOGEE finds systematically higher Mg abundances with respect to the GES. The ages based on the [C/N] ratio reveal a bimodal age distribution, with a major old population at 10 Gyr, with a decreasing tail towards younger stars. A comparison of stellar parameters determined by APOGEE and those determined by other sources reveals detectable systematic offsets, in particular for spectroscopic surface gravity estimates. In general, we find a good agreement between individual abundances of O, Na, Mg, Al, Si, K, Ca, Cr, Mn, Co, and Ni from APOGEE with that of literature values. Conclusions: We have shown that in general APOGEE data show a good agreement in terms of MDF and individual chemical abundances with respect to literature works. Using the [C/N] ratio we found a significant fraction of young stars in BW.

  12. Attitude Control Subsystem for the Advanced Communications Technology Satellite

    Science.gov (United States)

    Hewston, Alan W.; Mitchell, Kent A.; Sawicki, Jerzy T.

    1996-01-01

    This paper provides an overview of the on-orbit operation of the Attitude Control Subsystem (ACS) for the Advanced Communications Technology Satellite (ACTS). The three ACTS control axes are defined, including the means for sensing attitude and determining the pointing errors. The desired pointing requirements for various modes of control as well as the disturbance torques that oppose the control are identified. Finally, the hardware actuators and control loops utilized to reduce the attitude error are described.

  13. Galactic stellar populations with APOGEE and Kepler

    Science.gov (United States)

    Johnson, J. A.; APOKASC Collaboration

    2016-09-01

    Understanding the history of baryons is key to understanding galaxy formation, as galaxies with very similar stellar mass and/or dark matter halo mass can have markedly different morphologies in their stellar light. Stars are a useful way to study this history, because properties such as their composition, age, and orbital motion can map galaxy formation and evolution. Lightcurves from the Kepler mission, both original and extended, provide asteroseismic parameters, such as Δ ν and ν_max, and rotation periods. The high-resolution near-infrared APOGEE spectroscopic survey is observing an extensive sample of red giants and cool dwarfs in both the Kepler and K2 fields to provide composition and effective temperature measurements. These spectroscopic and seismic parameters can be combined to yield ages, important for dissecting the history of the Milky Way. Results based on this combination have already been published in the first APOKASC catalog. Among the interesting results about stellar populations so far are the presence of a large metallicity spread in the young secondary red clump population at the solar circle, the identification of young, yet α-rich stars, and the detection of a field blue straggler descendant. The K2 fields along the ecliptic will extend the possibilities of these techniques to new lines of sight in the Galaxy and provide a much more representative sample of Galactic populations with seismic and spectroscopic information.

  14. Research on Coal Exploration Technology Based on Satellite Remote Sensing

    Directory of Open Access Journals (Sweden)

    Dong Xiao

    2016-01-01

    Full Text Available Coal is the main source of energy. In China and Vietnam, coal resources are very rich, but the exploration level is relatively low. This is mainly caused by the complicated geological structure, the low efficiency, the related damage, and other bad situations. To this end, we need to make use of some advanced technologies to guarantee the resource exploration is implemented smoothly and orderly. Numerous studies show that remote sensing technology is an effective way in coal exploration and measurement. In this paper, we try to measure the distribution and reserves of open-air coal area through satellite imagery. The satellite picture of open-air coal mining region in Quang Ninh Province of Vietnam was collected as the experimental data. Firstly, the ENVI software is used to eliminate satellite imagery spectral interference. Then, the image classification model is established by the improved ELM algorithm. Finally, the effectiveness of the improved ELM algorithm is verified by using MATLAB simulations. The results show that the accuracies of the testing set reach 96.5%. And it reaches 83% of the image discernment precision compared with the same image from Google.

  15. Application of SAW technology in satellites for mobile services

    Science.gov (United States)

    Andreassen, O.; Viddal, V.; Galteland, J.

    1990-03-01

    Two surface acoustic wave (SAW) technologies for IF processing in a mobile satellite are discussed. The components and operations of the SAW filters method and the SAW filtering, routing, and beamforming concept are described. The capabilities of these two concepts are evaluated and compared. It is observed that the use of SAW filters is the more conventional and mature technology; it performs the channelizing function with a bank of SAW filters and routing of these channels by a switch matrix arrangement. The SAW filtering, routing, and beamforming concept is a more advanced technology that has the ability to give high resolution at low cost in volume and power; however, it has a high power consumption at large total processed bandwidth.

  16. ASPCAP: The APOGEE Stellar Parameter and Chemical Abundances Pipeline

    Science.gov (United States)

    García Pérez, Ana E.; Allende Prieto, Carlos; Holtzman, Jon A.; Shetrone, Matthew; Mészáros, Szabolcs; Bizyaev, Dmitry; Carrera, Ricardo; Cunha, Katia; García-Hernández, D. A.; Johnson, Jennifer A.; Majewski, Steven R.; Nidever, David L.; Schiavon, Ricardo P.; Shane, Neville; Smith, Verne V.; Sobeck, Jennifer; Troup, Nicholas; Zamora, Olga; Weinberg, David H.; Bovy, Jo; Eisenstein, Daniel J.; Feuillet, Diane; Frinchaboy, Peter M.; Hayden, Michael R.; Hearty, Fred R.; Nguyen, Duy C.; O'Connell, Robert W.; Pinsonneault, Marc H.; Wilson, John C.; Zasowski, Gail

    2016-06-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R ≈ 22,500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using χ2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.

  17. ASPCAP: The Apogee Stellar Parameter and Chemical Abundances Pipeline

    CERN Document Server

    Pérez, Ana E García; Holtzman, Jon A; Shetrone, Matthew; Mészáros, Szabolcs; Bizyaev, Dmitry; Carrera, Ricardo; Cunha, Katia; García-Hernández, D A; Johnson, Jennifer A; Majewski, Steven R; Nidever, David L; Schiavon, Ricardo P; Shane, Neville; Smith, Verne V; Sobeck, Jennifer; Troup, Nicholas; Zamora, Olga; Bovy, Jo; Eisenstein, Daniel J; Feuillet, Diane; Frinchaboy, Peter M; Hayden, Michael R; Hearty, Fred R; Nguyen, Duy C; O'Connell, Robert W; Pinsonneault, Marc H; Weinberg, David H; Wilson, John C; Zasowski, Gail

    2015-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R=22, 500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using chi-2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization, and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, wh...

  18. CTS United States experiments - A progress report. [Communications Technology Satellite for high power broadcasting

    Science.gov (United States)

    Robbins, W. H.; Donoughe, P. L.

    1976-01-01

    The Communications Technology Satellite (CTS) is a high-power broadcast satellite launched by NASA on January 17, 1976. CTS is the first satellite to operate at a frequency of 12 gigahertz and incorporates technology making possible new satellite telecommunications services. CTS is a cooperative program of the United States and Canada. This paper presents the results of the United States experimental activity to date. Wide segments of the population are involved in the Experiments Program, including the scientific community, other government agencies, industry, and the education and health entities. The experiments are associated with both technological objectives and the demonstration of new community and social services via satellite.

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

    Science.gov (United States)

    Nordberg, W.

    1975-01-01

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

  20. Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 2

    Science.gov (United States)

    Greenburg, J. S.; Kaplan, M.; Fishman, J.; Hopkins, C.

    1985-01-01

    The computational procedures used in the evaluation of spacecraft technology programs that impact upon commercial communication satellite operations are discussed. Computer programs and data bases are described.

  1. A Study on the Timing Technology of Digital Satellite TV

    Science.gov (United States)

    Song, K. X.

    2013-03-01

    Based on analyzing and summarizing the modern timing technologies, through intensive analyzing the characteristics of the current digital satellite TV signals, and without changing equipment configuration of the digital satellite TV transmitter and signal system, this thesis puts forward the method of using the digital TV signal to transmit the standard time and frequency, and carries out the relevant researches on the key technologies. Meanwhile, we make experiments on the digital satellite TV timing system, which are based on the proposed timing method. Through analyzing the test data, the timing method is proved practicable and with a high precision. The main research work is as follows: (1) Firstly, we summarize the necessary conditions and key elements required for timing by analyzing the characteristics of modern timing methods, and analyze China’s digital satellite TV signal system; Secondly, we propose the idea that the inherent flag bit of source coding signals of TV is used to trigger event of timing and then complete this task; Thirdly, we propose the principle of transmitting the standard time and frequency through digital satellite TV signal, analyze the error sources which affect the accuracy of timing, and find the ways to reduce the error effect. (2) Synchronization clock signal is recovered from asynchronous serial interface (ASI) data to achieve bit synchronization, so that the transmitter can accurately access to the high-precision standard time code. At the same time, the TV signal transmission delay on the transmission channel is accurately measured in order to supply the necessary information for timing. Based on the analysis of the ASI data transmission characteristics and transmission standards, a method using over-sampling to recover the ASI clock signal and synchronize the digital TV signal source coding is proposed in this paper. This method is proved effective by the implementation on the FPGA (Field Programmable Gate Array). (3) Using

  2. Toward a Comprehensive Sample of VLM Chemical Abundances with APOGEE

    Science.gov (United States)

    Aganze, Christian; Birky, Jessica L.; Theissen, Christopher; Burgasser, Adam J.; Schmidt, Sarah J.; Teske, Johanna K.; Stassun, Keivan G.; Bird, Jonathan C.

    2017-01-01

    Understanding the formation and evolution of very low-mass (VLM, M R~ 22,500 spectrograph mounted on the 2.5 m SDSS telescope that has provided near-infrared (H-band, 1.5-1.7 micron) spectra of more than 150,000 stars down to a magnitude of H=12.2. The reduction pipeline produces precise, model-dependent determinations for temperature, surface gravity, metallicity and individual abundances for the majority of these targets. However, below Teff ≈ 3000 K, this pipeline does not produce reliable parameters. We have identified a sample of 46 M3-L5 dwarfs observed by this survey at distances of 5-30 pc by cross-matching the APOGEE catalog to catalogs of known late-M, L, T dwarfs. We characterize this sample using existing photometry and spectroscopy from other surveys, and examine the properties of their APOGEE spectra, including correlating atomic equivalent width measurements to parameters inferred from model fits of broad-band, low-resolution data and defining empirical trends . We discuss a potential sample for further APOGEE measurements that would diversify these trends and allow the use of APOGEE data to examine kinematics, rotation and multiplicity across the hydrogen-burning mass limit.This work is supported the SDSS Faculty and Student (FAST) initiative.

  3. The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

    DEFF Research Database (Denmark)

    Majewski, Steven R.; Schiavon, Ricardo P.; Frinchaboy, Peter M.

    2017-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the...

  4. Autonomous, agile micro-satellites and supporting technologies

    Energy Technology Data Exchange (ETDEWEB)

    Breitfeller, E; Dittman, M D; Gaughan, R J; Jones, M S; Kordas, J F; Ledebuhr, A G; Ng, L C; Whitehead, J C; Wilson, B

    1999-07-19

    This paper updates the on-going effort at Lawrence Livermore National Laboratory to develop autonomous, agile micro-satellites (MicroSats). The objective of this development effort is to develop MicroSats weighing only a few tens of kilograms, that are able to autonomously perform precision maneuvers and can be used telerobotically in a variety of mission modes. The required capabilities include satellite rendezvous, inspection, proximity-operations, docking, and servicing. The MicroSat carries an integrated proximity-operations sensor-suite incorporating advanced avionics. A new self-pressurizing propulsion system utilizing a miniaturized pump and non-toxic mono-propellant hydrogen peroxide was successfully tested. This system can provide a nominal 25 kg MicroSat with 200-300 m/s delta-v including a warm-gas attitude control system. The avionics is based on the latest PowerPC processor using a CompactPCI bus architecture, which is modular, high-performance and processor-independent. This leverages commercial-off-the-shelf (COTS) technologies and minimizes the effects of future changes in processors. The MicroSat software development environment uses the Vx-Works real-time operating system (RTOS) that provides a rapid development environment for integration of new software modules, allowing early integration and test. We will summarize results of recent integrated ground flight testing of our latest non-toxic pumped propulsion MicroSat testbed vehicle operated on our unique dynamic air-rail.

  5. NASA ACTS Multibeam Antenna (MBA) System. [Advanced Communications Technology Satellite

    Science.gov (United States)

    Choung, Youn H.; Stiles, W. Herschel; Wu, Joseph; Wong, William C.; Chen, C. Harry

    1986-01-01

    The design of the Advanced Communications Technology Satellite MBA system, which provides both spot beam and scanning beam coverage to both high and low burst rates data-users is examined. The MBA consists of receive and transmit antennas installed on a common precision mounting platform that is integrated to the bus through three flexures; a lightweight system with low thermal distortion is obtained by using composite materials for the MBA structures. The RF design, which is a Cassegrain reflector with a large equivalent focal length/aperture size, is described. Consideration is given to the position of the feed in order to minimize scan loss and sidelobe levels, the size of the subreflector in order to minimize feed spillover, and antenna performance degradation caused by reflector surface distortion. Breadbroad model test result reveal that the maximum sidelobe level outside the 2.5 HPBW region is -30 dB or lower relative to the power.

  6. Gossamer Technology to Deorbit LEO Non-Propulsion Fitted Satellite

    Science.gov (United States)

    Dupuy, C.; LeCouls, O.

    2010-01-01

    Since 2004, CNES has decided to apply the end of life Code of Conduct rules to debris mitigation. Originally drawn up by the main European space agencies, it contains basic rules to be applied in space in order to limit the increase of orbital debris. In low Earth orbit, the rule is to limit in-orbit lifetime to 25 years after the end of the operational mission, or else to transfer to a graveyard orbit above 2000 km. In order to follow these instructions, a task force was set up in 2005 to find the best way to implement them on MICROSCOPE and CNES microsatellite family (MYRIADE). This 200-kg spacecraft should be launched in 2014 on a 790-km high circular orbit. Without targeted action, its natural re-entry would occur in 67 years. Two strategies to reduce this time period were compared: propulsive maneuvers at the end of the mission or the deployment of large surfaces to increase significantly the ballistic coefficient. At the end of the trade off, it was recommended: .. For the non-propulsive system fitted satellites, to use passive aerobraking by deployment of added surface, .. For satellites having propulsive subsystem in baseline for mission purposes, to keep sufficient propellant and implement specific maneuvers. The poster gives an overview of the process that led to the development of a deployable aerobraking wing using a lightweight aluminized Kapton membrane and an inflatable aluminum laminate boom. The main requirements; The trade off among various aerobraking solutions; The development plan. This technology presents a very attractive potential and it could be a first step in using of inflatable technology on spaces vehicles, before to deal with others more exigent applications.

  7. The Human-Technological Interface: An Analysis of a Satellite Communication Learning Environment.

    Science.gov (United States)

    Collins, Valerie A. C.; Murphy, Peter J.

    1987-01-01

    The effectiveness of distance education methods that involve direct interaction between the student and communications satellite technology is discussed, drawing on experiences in British Columbia adult distance education programs using interactive instructional television and other modern technologies. (MSE)

  8. The ACTS Flight System - Cost-Effective Advanced Communications Technology. [Advanced Communication Technology Satellite

    Science.gov (United States)

    Holmes, W. M., Jr.; Beck, G. A.

    1984-01-01

    The multibeam communications package (MCP) for the Advanced Communications Technology Satellite (ACTS) to be STS-launched by NASA in 1988 for experimental demonstration of satellite-switched TDMA (at 220 Mbit/sec) and baseband-processor signal routing (at 110 or 27.5 Mbit/sec) is characterized. The developmental history of the ACTS, the program definition, and the spacecraft-bus and MCP parameters are reviewed and illustrated with drawings, block diagrams, and maps of the coverage plan. Advanced features of the MPC include 4.5-dB-noise-figure 30-GHz FET amplifiers and 20-GHz TWTA transmitters which provide either 40-W or 8-W RF output, depending on rain conditions. The technologies being tested in ACTS can give frequency-reuse factors as high as 20, thus greatly expanding the orbit/spectrum resources available for U.S. communications use.

  9. Technology for a quasi-GSO satellite communications system

    OpenAIRE

    Katagi, T.; Yonezawa, R.; Chiba, I.; Urasaki, S.

    1999-01-01

    In this paper, a satellite communications system using a Quasi Geostationary Satellite Orbit (Quasi-GSO) is proposed. A 24-hour period Quasi-GSO system could give high quality communication to high latitude regions with its satellites observed from earth stations having high elevation angles. In this paper, a system concept and a deployable flat antenna with light weight antenna elements are described proposing it to be a good candidate for mobile communications satellite use.

  10. APOGEE strings: a fossil record of the gas kinematic structure

    CERN Document Server

    Hacar, A; Forbrich, J; Meingast, S; Kubiak, K; Grossschedl, J

    2016-01-01

    We compare APOGEE radial velocities (RVs) of young stars in the Orion A cloud with CO line gas emission and find a correlation between the two at large-scales, in agreement with previous studies. However, at smaller scales we find evidence for the presence of substructure in the stellar velocity field. Using a Friends-of-Friends approach we identify 37 stellar groups with almost identical RVs. These groups are not randomly distributed but form elongated chains or strings of stars with five or more members with low velocity dispersion, across lengths of 1-1.5~pc. The similarity between the kinematic properties of the APOGEE strings and the internal velocity field of the chains of dense cores and fibers recently identified in the dense ISM is striking and suggests that for most of the Orion A cloud, young stars keep memory of the parental gas substructure where they originated.

  11. Evolution of the NOAA National Weather Service Satellite Broadcast Network (SBN) to Europe's DVB-S satellite communications technology standard

    Science.gov (United States)

    Cragg, Phil; Brockman, William E.

    2006-08-01

    The National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS) uses a commercial Satellite Broadcast Network (SBN) to distribute weather data to the NWS AWIPS workstations and National Centers and to NWS Family of Service Users. Advances in science and technology from NOAA's observing systems, such as remote sensing satellites and NEXRAD radars, and advances in Numeric Weather Prediction have greatly increased the volume of data to be transmitted via the SBN. The NOAA-NWS SBN Evolution Program did a trade study resulting in the selection of Europe's DVB-S communication protocol as the basis for enabling a significant increase in the SBN capacity. The Digital Video Broadcast (DVB) group, started to develop digital TV for Europe through satellite broadcasting, has become the current standard for defining technology for satellite broadcasting of digital data for much of the world. NOAA-NWS implemented the DVB-S with inexpensive, Commercial Off The Shelf receiving equipment. The modernized NOAA-NWS SBN meets current performance goals and provides the basis for continued future expansion with no increase in current communication costs. This paper discusses aspects of the NOAA-NWS decision and the migration to the DVB-S standard for its commercial satellite broadcasts of observations and Numerical Weather Prediction data.

  12. Target Selection for the Apache Point Observatory Galactic Evolution Experiment (APOGEE)

    CERN Document Server

    Zasowski, G; Frinchaboy, P M; Majewski, S R; Nidever, D L; Pinto, H J Rocha; Girardi, L; Andrews, B; Chojnowski, S D; Cudworth, K M; Jackson, K; Munn, J; Skrutskie, M F; Beaton, R L; Blake, C H; Covey, K; Deshpande, R; Epstein, C; Fabbian, D; Fleming, S W; Hernandez, A Garcia; Herrero, A; Mahadevan, S; Meszaros, Sz; Schultheis, M; Sellgren, K; Terrien, R; van Saders, J; Prieto, C Allende; Bizyaev, D; Burton, A; Cunha, K; da Costa, L N; Hasselquist, S; Hearty, F; Holtzman, J; Perez, A E Garcia; Maia, M A G; O'Connell, R W; O'Donnell, C; Pinsonneault, M; Santiago, B X; Schiavon, R P; Shetrone, M; Smith, V; Wilson, J C

    2013-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all Galactic environments (i.e., bulge, disk, and halo), with the principal goal of constraining dynamical and chemical evolution models of the Milky Way. APOGEE takes advantage of the reduced effects of extinction at infrared wavelengths to observe the inner Galaxy and bulge at an unprecedented level of detail. The survey's broad spatial and wavelength coverage enables users of APOGEE data to address numerous Galactic structure and stellar populations issues. In this paper we describe the APOGEE targeting scheme and document its various target classes to provide the necessary background and reference information to analyze samples of APOGEE data with awareness of the imposed selection criteria and resulting sample properties. APOGEE's primary sample consists of ~100,000 red giant stars, selected to minimize observational biases in age and metallicity. We present the methodology and ...

  13. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment

    OpenAIRE

    Wu Xiao-po; Zhao Hai-yang; Xi Song-tao

    2014-01-01

    Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  14. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment

    Directory of Open Access Journals (Sweden)

    Wu Xiao-po

    2014-06-01

    Full Text Available Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  15. Dutch Micro Systems Technology for the Next Generation of Small Satellites

    NARCIS (Netherlands)

    Gill, E.; Monna, G.L.E.; Scherpen, J.M.A.; Verhoeven, C.J.M.

    2007-01-01

    Advanced microelectronics and Micro Systems Technology (MST) enable an increased functional performance of small satellites with decreased demands on mass, size and power. The research and development cluster MISAT stimulates the design and development of advanced small satellite platforms based on

  16. President's Task Force on Communications Policy. Domestic Applications of Communication Satellite Technology. Staff Paper Four.

    Science.gov (United States)

    President's Task Force on Communications Policy, Washington, DC.

    A staff paper to the President's Task Force on Communications Policy examines the feasibility of a domestic communications satellite system. Although, with expected technological advancement, satellites may play a significant role in domestic transmission and are economically feasible right now, a number of remaining questions make the…

  17. SATELLITE GRAVITY SURVEYING TECHNOLOGY AND RESEARCH OF EARTH'S GRAVITY FIELD

    Institute of Scientific and Technical Information of China (English)

    NingJinsheng

    2003-01-01

    This is a summarized paper.Two topics are discussed:Firstly,the comcept,development and application of four kinds of satellite gravity surveying technology are introduced;Secondly,some problems of theory and method,which must be considered in the study lf the Earth's gravity field based on satellite gravity data,are expounded.

  18. Dutch Micro Systems Technology for the Next Generation of Small Satellites

    NARCIS (Netherlands)

    Gill, E.; Monna, G.L.E.; Scherpen, J.M.A.; Verhoeven, C.J.M.

    2007-01-01

    Advanced microelectronics and Micro Systems Technology (MST) enable an increased functional performance of small satellites with decreased demands on mass, size and power. The research and development cluster MISAT stimulates the design and development of advanced small satellite platforms based on

  19. Study on fault locating technology for satellite power system

    Institute of Scientific and Technical Information of China (English)

    LONG Bing; JIANG Xing-wei; SONG Zheng-ji

    2005-01-01

    It is currently prevalent to locate faults for a satellite power system based on an expert system, not utilizing all the available information provided by tests. The casual network model for a satellite power system is presented. Considerations for failure probability of each component of the power system, the cost of applying each test, the influence of a precedent test result on the next test selection, and an optimal sequential testing algorithm for fault location is presented. This program is applied to locate the failure component of the power system of a satellite. The results show this program is very effective and it is very fast to generate an optimal diagnosis tree.

  20. The Second Young Engineers' Satellite: Innovative Technology through Education

    Science.gov (United States)

    Fujii, Hironori A.; Kruijff, Michiel; van der Heide, Erik J.; Watanabe, Takeo

    The second Young Engineers' Satellite,YES2, is the longest manmade structure launched in 2007 and is space piggybacked on the Foton-M3 microgravity platform with the objective of a controlled deployment of a 32km tether. This paper introduces the object and the flight results of YES2 and the performance of the satellite is studied in comparison of the simulations and ground tests with respect to the flight results.

  1. The rise and fall of COMSAT technology, business, and government in satellite communications

    CERN Document Server

    Whalen, D

    2014-01-01

    Satellite communications grosses over 100 billion annually and is heading toward 200 billion. COMSAT started all of this in 1963 when it was organized in compliance with the Communications Satellite Act of 1962. COMSAT was responsible for choosing geosynchronous earth orbit (GEO), forming INTELSAT, and generally promoting the technological change that saw satellite power increase from the 40 watts of Early Bird (INTELSAT I) to the almost 10 kilowatts of INTELSAT IX; earth station antennas were reduced from 30 meters to 1 meter. The business of satellite communications was expanded to mobile co

  2. Network design for telemedicine--e-health using satellite technology.

    Science.gov (United States)

    Graschew, Georgi; Roelofs, Theo A; Rakowsky, Stefan; Schlag, Peter M

    2008-01-01

    Over the last decade various international Information and Communications Technology networks have been created for a global access to high-level medical care. OP 2000 has designed and validated the high-end interactive video communication system WinVicos especially for telemedical applications, training of the physician in a distributed environment, teleconsultation and second opinion. WinVicos is operated on a workstation (WoTeSa) using standard hardware components and offers a superior image quality at a moderate transmission bandwidth of up to 2 Mbps. WoTeSa / WinVicos have been applied for IP-based communication in different satellite-based telemedical networks. In the DELTASS-project a disaster scenario was analysed and an appropriate telecommunication system for effective rescue measures for the victims was set up and evaluated. In the MEDASHIP project an integrated system for telemedical services (teleconsultation, teleelectro-cardiography, telesonography) on board of cruise ships and ferries has been set up. EMISPHER offers an equal access for most of the countries of the Euro-Mediterranean area to on-line services for health care in the required quality of service. E-learning applications, real-time telemedicine and shared management of medical assistance have been realized. The innovative developments in ICT with the aim of realizing a ubiquitous access to medical resources for everyone at any time and anywhere (u-Health) bear the risk of creating and amplifying a digital divide in the world. Therefore we have analyzed how the objective needs of the heterogeneous partners can be joined with the result that there is a need for real integration of the various platforms and services. A virtual combination of applications serves as the basic idea for the Virtual Hospital. The development of virtual hospitals and digital medicine helps to bridge the digital divide between different regions of the world and enables equal access to high-level medical care. Pre

  3. The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

    Science.gov (United States)

    Majewski, Steven R.; Schiavon, Ricardo P.; Frinchaboy, Peter M.; Allende Prieto, Carlos; Barkhouser, Robert; Bizyaev, Dmitry; Blank, Basil; Brunner, Sophia; Burton, Adam; Carrera, Ricardo; Chojnowski, S. Drew; Cunha, Kátia; Epstein, Courtney; Fitzgerald, Greg; García Pérez, Ana E.; Hearty, Fred R.; Henderson, Chuck; Holtzman, Jon A.; Johnson, Jennifer A.; Lam, Charles R.; Lawler, James E.; Maseman, Paul; Mészáros, Szabolcs; Nelson, Matthew; Nguyen, Duy Coung; Nidever, David L.; Pinsonneault, Marc; Shetrone, Matthew; Smee, Stephen; Smith, Verne V.; Stolberg, Todd; Skrutskie, Michael F.; Walker, Eric; Wilson, John C.; Zasowski, Gail; Anders, Friedrich; Basu, Sarbani; Beland, Stephane; Blanton, Michael R.; Bovy, Jo; Brownstein, Joel R.; Carlberg, Joleen; Chaplin, William; Chiappini, Cristina; Eisenstein, Daniel J.; Elsworth, Yvonne; Feuillet, Diane; Fleming, Scott W.; Galbraith-Frew, Jessica; García, Rafael A.; García-Hernández, D. Aníbal; Gillespie, Bruce A.; Girardi, Léo; Gunn, James E.; Hasselquist, Sten; Hayden, Michael R.; Hekker, Saskia; Ivans, Inese; Kinemuchi, Karen; Klaene, Mark; Mahadevan, Suvrath; Mathur, Savita; Mosser, Benoît; Muna, Demitri; Munn, Jeffrey A.; Nichol, Robert C.; O'Connell, Robert W.; Parejko, John K.; Robin, A. C.; Rocha-Pinto, Helio; Schultheis, Matthias; Serenelli, Aldo M.; Shane, Neville; Silva Aguirre, Victor; Sobeck, Jennifer S.; Thompson, Benjamin; Troup, Nicholas W.; Weinberg, David H.; Zamora, Olga

    2017-09-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the Sloan 2.5 m Telescope, APOGEE has collected a half million high-resolution (R ˜ 22,500), high signal-to-noise ratio (>100), infrared (1.51-1.70 μm) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design—hardware, field placement, target selection, operations—and gives an overview of these aspects as well as the data reduction, analysis, and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity, and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12 and later releases, all of the APOGEE data products are publicly available.

  4. Cosmic rays and other space weather effects influenced on satellite operation, technologies, biosphere and people health

    Science.gov (United States)

    Lev, Dorman

    2016-07-01

    Satellite anomalies (or malfunctions), including total distortion of electronics and loose of some satellites cost for Insurance Companies billions dollars per year. During especially active periods the probability of big satellite anomalies and their loosing increased very much. Now, when a great number of civil and military satellites are continuously worked for our practice life, the problem of satellite anomalies became very important. Many years ago about half of satellite anomalies were caused by technical reasons (for example, for Russian satellites Kosmos), but with time with increasing of production quality, this part became smaller and smaller. The other part, which now is dominated, caused by different space weather effects (energetic particles of CR and generated/trapped in the magnetosphere, and so on). We consider only satellite anomalies not caused by technical reasons: the total number of such anomalies about 6000 events, and separately for high and low altitude orbit satellites (5000 and about 800 events, correspondingly for high and low altitude satellites). No relation was found between low and high altitude satellite anomalies. Daily numbers of satellite anomalies, averaged by a superposed epoch method around sudden storm commencements and solar proton event onsets for high (>1500 km) and low (account under developing of the anomaly frequency models and forecasting. We consider also influence of CR on frequency of gene mutations and evolution of biosphere (we show that if it will be no CR, the Earth's civilization will be start only after milliards years later, what will be too late), CR role in thunderstorm phenomena and discharges, space weather effects on space technologies and radiation effects from solar and galactic CR in dependence of cutoff rigidities and altitude, influence magnetic storms accompanied by CR Forbush-effects on people health (increasing frequency of infarct myocardial and brain strokes), increasing frequency of car

  5. Solid state device technology for Solar Power Satellite

    Science.gov (United States)

    Weir, D. G.

    1980-01-01

    The feasibility of using solid state elements in the solar power satellite transmitter system is addressed. Recommendations are given concerning device types, the antenna modules, and the overall antenna system. The development of a solid state amplifier based on GaAs field effect transistor devices is also described.

  6. Technology development of the Space Transportation System mission and terrestrial applications of satellite technology

    Science.gov (United States)

    1981-01-01

    The Space Transportation System (STS) is discussed, including the launch processing system, the thermal protection subsystem, meteorological research, sound supression water system, rotating service structure, improved hypergol or removal systems, fiber optics research, precision positioning, remote controlled solid rocket booster nozzle plugs, ground operations for Centaur orbital transfer vehicle, parachute drying, STS hazardous waste disposal and recycle, toxic waste technology and control concepts, fast analytical densitometry study, shuttle inventory management system, operational intercommunications system improvement, and protective garment ensemble. Terrestrial applications are also covered, including LANDSAT applications to water resources, satellite freeze forecast system, application of ground penetrating radar to soil survey, turtle tracking, evaluating computer drawn ground cover maps, sparkless load pulsar, and coupling a microcomputer and computing integrator with a gas chromatograph.

  7. The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

    CERN Document Server

    Majewski, Steven R; Frinchaboy, Peter M; Prieto, Carlos Allende; Barkhouser, Robert; Bizyaev, Dmitry; Blank, Basil; Brunner, Sophia; Burton, Adam; Carrera, Ricardo; Chojnowski, S Drew; Cunha, Katia; Epstein, Courtney; Fitzgerald, Greg; Perez, Ana E Garcia; Hearty, Fred R; Henderson, Chuck; Holtzman, Jon A; Johnson, Jennifer A; Lam, Charles R; Lawler, James E; Maseman, Paul; Meszaros, Szabolcs; Nelson, Matthew; Nguyen, Duy Coung; Nidever, David L; Pinsonneault, Marc; Shetrone, Matthew; Smee, Stephen; Smith, Verne V; Stolberg, Todd; Skrutskie, Michael F; Walker, Eric; Wilson, John C; Zasowski, Gail; Anders, Friedrich; Basu, Sarbani; Beland, Stephane; Blanton, Michael R; Bovy, Jo; Brownstein, Joel R; Carlberg, Joleen; Chaplin, William; Chiappini, Cristina; Eisenstein, Daniel J; Elsworth, Yvonne; Feuillet, Diane; Fleming, Scott W; Galbraith-Frew, Jessica; Garcia, Rafael A; Garcia-Hernandez, D Anibal; Gillespie, Bruce A; Girardi, Leo; Gunn, James E; Hasselquist, Sten; Hayden, Michael R; Hekker, Saskia; Ivans, Inese; Kinemuchi, Karen; Klaene, Mark; Mahadevan, Suvrath; Mathur, Savita; Mosser, Benoit; Muna, Demitri; Munn, Jeffrey A; Nichol, Robert C; O'Connell, Robert W; Robin, A C; Rocha-Pinto, Helio; Schultheis, Matthias; Serenelli, Aldo M; Shane, Neville; Aguirre, Victor Silva; Sobeck, Jennifer S; Thompson, Benjamin; Troup, Nicholas W; Weinberg, David H; Zamora, Olga

    2015-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three year observing campaign on the Sloan 2.5-m Telescope, APOGEE has collected a half million high resolution (R~22,500), high S/N (>100), infrared (1.51-1.70 microns) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design---hardware, field placement, target selection, operations---and gives an overview of these aspects as well as the data reduction, analysis and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of scienc...

  8. Determining Ages of APOGEE Giants with Known Distances

    CERN Document Server

    Feuillet, Diane K; Holtzman, Jon; Girardi, Leo; MacDonald, Nick; Majewski, Steven R; Nidever, David L

    2015-01-01

    We present a sample of local red giant stars observed using the New Mexico State University 1 m telescope with the APOGEE spectrograph, for which we estimate stellar ages and the age distribution from the high-resolution spectroscopic stellar parameters and accurate distance measurements from Hipparcos. The high-resolution (R ~ 23,000), near infrared (H-band, 1.5-1.7 micron) APOGEE spectra provide measurements of the stellar atmospheric parameters (temperature, surface gravity, [M/H], and [alpha/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 40%. For red giants, the relatively rapid evolution of stars up the red giant branch allows the age to be constrained based on the mass. We examine methods of estimating age using both the mass-age relation directly and a Bayesian isochrone matching of measured parameters, assuming a constant star formation history (SFH). To i...

  9. Status of the fast mission: Micro-satellite formation flying for technology, science and education

    NARCIS (Netherlands)

    Guo, J.; Maessen, D.C.; Gill, E.K.A.; Moon, S.G.; Zheng, G.

    2009-01-01

    FAST (Formation for Atmospheric Science and Technology demonstration) is a cooperative Dutch Chinese formation flying mission led by Delft University of Technology (TU Delft) in the Netherlands and Tsinghua University in China. It is expected to be the first international micro-satellite formation f

  10. Status of the fast mission: Micro-satellite formation flying for technology, science and education

    NARCIS (Netherlands)

    Guo, J.; Maessen, D.C.; Gill, E.K.A.; Moon, S.G.; Zheng, G.

    2009-01-01

    FAST (Formation for Atmospheric Science and Technology demonstration) is a cooperative Dutch Chinese formation flying mission led by Delft University of Technology (TU Delft) in the Netherlands and Tsinghua University in China. It is expected to be the first international micro-satellite formation

  11. Status of the fast mission: Micro-satellite formation flying for technology, science and education

    NARCIS (Netherlands)

    Guo, J.; Maessen, D.C.; Gill, E.K.A.; Moon, S.G.; Zheng, G.

    2009-01-01

    FAST (Formation for Atmospheric Science and Technology demonstration) is a cooperative Dutch Chinese formation flying mission led by Delft University of Technology (TU Delft) in the Netherlands and Tsinghua University in China. It is expected to be the first international micro-satellite formation f

  12. Applications technology satellite F&G /ATS F&G/ mobile terminal.

    Science.gov (United States)

    Greenbaum, L. A.; Baker, J. L.

    1971-01-01

    The mobile terminal is a flexible, easily transportable system. The terminal design incorporates a combination of unique and proven hardware to provide maximum utility consistent with reliability. The flexibility built into the system will make it possible to satisfy the requirements of the applications technology satellite program concerned with the conduction of various spacecraft technology experiments. The terminal includes two parabolic antennas.

  13. Next Generation Solar Array Technologies for Small Satellites

    OpenAIRE

    Fosness, E.; Guerrero, J.; Mayberry, C.; Carpenter, B.; Goldstein, D.

    2002-01-01

    Recent advances in Shape Memory Alloy (SMA), Elastic Memory Composites (EMC), and ultra- light composites along with thin-film Copper-Indium- Diselinide (CIS) photovoltaics have offered the potential to provide solar array systems for small satellites that are significantly lighter than the current state of the practice. The Air Force Research Laboratory (AFRL), National Aeronautics and Space Administration (NASA) Langley, Defense Advanced Research Projects Agency (DARPA), and Lockheed Martin...

  14. The Application of the Technology of 3D Satellite Cloud Imaging in Virtual Reality Simulation

    Directory of Open Access Journals (Sweden)

    Xiao-fang Xie

    2007-05-01

    Full Text Available Using satellite cloud images to simulate clouds is one of the new visual simulation technologies in Virtual Reality (VR. Taking the original data of satellite cloud images as the source, this paper depicts specifically the technology of 3D satellite cloud imaging through the transforming of coordinates and projection, creating a DEM (Digital Elevation Model of cloud imaging and 3D simulation. A Mercator projection was introduced to create a cloud image DEM, while solutions for geodetic problems were introduced to calculate distances, and the outer-trajectory science of rockets was introduced to obtain the elevation of clouds. For demonstration, we report on a computer program to simulate the 3D satellite cloud images.

  15. THE APPLICATION OF SATELLITE POSITIONING TECHNOLOGY AND ITS INDUSTRIALIZATION IN CHINA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Satellite positioning technology has been widely used in all kinds of military and civil land, marine, space and aeronautical target positioning tasks, naviga tion activities and accurate surveying measurements since 90 s in the last cen tury due to its advantage in providing all-weather, real-time, three dimensional and high precision positioning information, as well as speed and accurate timing information. By now, it has already formed a new hi-tech industry basically.This paper briefly reviews the development of the global satellite positioning and navigation technologies including the basic information of China's "Plough navigation system", introduces the history of satellite positioning technology and its major application fields as well as the status quo of this being industri alized trade in China, gives an account of the writers' vision for the application and prospect of the satellite positioning technologies in China, and approaches the tactics and stresses of the satellite positioning technology's application and its industrialization future in China.

  16. Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 1

    Science.gov (United States)

    Greenburg, J. S.; Gaelick, C.; Kaplan, M.; Fishman, J.; Hopkins, C.

    1985-01-01

    Commercial organizations as well as government agencies invest in spacecraft (S/C) technology programs that are aimed at increasing the performance of communications satellites. The value of these programs must be measured in terms of their impacts on the financial performane of the business ventures that may ultimately utilize the communications satellites. An economic evaluation and planning capability was developed and used to assess the impact of NASA on-orbit propulsion and space power programs on typical fixed satellite service (FSS) and direct broadcast service (DBS) communications satellite business ventures. Typical FSS and DBS spin and three-axis stabilized spacecraft were configured in the absence of NASA technology programs. These spacecraft were reconfigured taking into account the anticipated results of NASA specified on-orbit propulsion and space power programs. In general, the NASA technology programs resulted in spacecraft with increased capability. The developed methodology for assessing the value of spacecraft technology programs in terms of their impact on the financial performance of communication satellite business ventures is described. Results of the assessment of NASA specified on-orbit propulsion and space power technology programs are presented for typical FSS and DBS business ventures.

  17. Technology programs and related policies - Impacts on communications satellite business ventures

    Science.gov (United States)

    Greenberg, J. S.

    1985-01-01

    The DOMSAT II stochastic communication satellite business venture financial planning simulation model is described. The specification of business scenarios and the results of several analyses are presented. In particular, the impacts of NASA on-orbit propulsion and power technology programs are described. The effects of insurance rates and self-insurance and of the use of the Space Shuttle and Ariane transportation systems on a typical fixed satellite service business venture are discussed.

  18. Technology programs and related policies - Impacts on communications satellite business ventures

    Science.gov (United States)

    Greenberg, J. S.

    1985-01-01

    The DOMSAT II stochastic communication satellite business venture financial planning simulation model is described. The specification of business scenarios and the results of several analyses are presented. In particular, the impacts of NASA on-orbit propulsion and power technology programs are described. The effects of insurance rates and self-insurance and of the use of the Space Shuttle and Ariane transportation systems on a typical fixed satellite service business venture are discussed.

  19. Versatile Satellite Architecture and Technology: A New Architecture for Low Cost Satellite Missions for Solar-Terrestrial Studies

    Science.gov (United States)

    Cook, T. A.; Chakrabarti, S.; Polidan, R.; Jaeger, T.; Hill, L.

    2011-12-01

    Early in the 20th century, automobiles appeared as extraordinary vehicles - and now they are part of life everywhere. Late in the 20th century, internet and portable phones appeared as innovations - and now omni-present requirements. At mid-century, the first satellites were launched into space - and now 50 years later - "making a satellite" remains in the domain of highly infrequent events. Why do all universities and companies not have their own satellites? Why is the work force capable of doing so remarkably small? Why do highly focused science objectives that require just a glimpse from space never get a chance to fly? Historically, there have been two primary impediments to place an experiment in orbit - high launch costs and the high cost of spacecraft systems and related processes. The first problem appears to have been addressed through the availability of several low-cost (< $10M) commercial launch opportunities. The Versatile Satellite Architecture and Technology (VerSAT) will address the second. Today's space missions are often large, complex and require development times typically a decade from conception to execution. In present risk-averse scenario, the huge expense of these one-of-a-kind mission architecture can only be justified if the technology required to make orders of magnitude gains is flight-proven at the time mission conception. VerSAT will complement these expensive missions which are "too large to fail" and the CUBESATs. A number of Geospace science experiments that could immediately take advantage of VerSAT have been identified. They range from the study of fundamental questions of the "ignorosphere" from a single satellite lasting a few days - a region of space that was probed once about 40 years ago, to a constellation of satellites which will disentangle the space and time ambiguity of the variability of ionospheric structures and their link to the storms in the Sun to long-term studies of the Sun-Earth system. VerSAT is a true

  20. CTS /Hermes/ - United States experiments and operations summary. [Communications Technology Satellite

    Science.gov (United States)

    Donoughe, P. L.; Hunczak, H. R.

    1977-01-01

    The U.S. experiments conducted with the Communications Technology Satellite, a joint Canadian-U.S. venture launched in 1976, are discussed. The 14/12 GHz frequencies employed by the 200-W transmitter on board the satellite provide two-way television and voice communications. Applications of the satellite in the categories of health care, community services and education are considered; experiments have also made use of the special properties of the super-high frequency band (e.g. link characterization and digital communications). Time-sharing of the 14/12 GHz communication between the U.S. and Canada has functioned well.

  1. Communications satellite business ventures - Measuring the impact of technology programmes and related policies

    Science.gov (United States)

    Greenberg, J. S.

    1986-01-01

    An economic evaluation and planning procedure which assesses the effects of various policies on fixed satellite business ventures is described. The procedure is based on a stochastic financial simulation model, the Domsat II, which evaluates spacecraft reliability, market performance, and cost uncertainties. The application of the Domsat II model to the assessment of NASA's ion thrusters for on-orbit propulsion and GaAs solar cell technology is discussed. The effects of insurance rates and the self-insurance option on the financial performance of communication satellite business ventures are investigated. The selection of a transportation system for placing the satellites into GEO is analyzed.

  2. Communications satellite business ventures - Measuring the impact of technology programmes and related policies

    Science.gov (United States)

    Greenberg, J. S.

    1986-01-01

    An economic evaluation and planning procedure which assesses the effects of various policies on fixed satellite business ventures is described. The procedure is based on a stochastic financial simulation model, the Domsat II, which evaluates spacecraft reliability, market performance, and cost uncertainties. The application of the Domsat II model to the assessment of NASA's ion thrusters for on-orbit propulsion and GaAs solar cell technology is discussed. The effects of insurance rates and the self-insurance option on the financial performance of communication satellite business ventures are investigated. The selection of a transportation system for placing the satellites into GEO is analyzed.

  3. Integrating Balloon and Satellite Operation Data Centers for Technology Readiness Assessment

    Science.gov (United States)

    Mattiello-Francisco, Fátima; Fernandes, Jose Oscar

    2016-07-01

    Stratospheric balloon-borne experiments have been one of the most effective ways to validate innovative space technology, taking the advantage of reduced development cycles and low cost in launching and operation. In Brazil, the National Institute for Space Research (INPE) has balloon and satellite ground infrastructures since the 1970´s and the 1990´s, respectively. In the recent past, a strategic approach was adopted on the modernization of balloon ground operation facilities for supporting the protoMIRAX experiment, an X-ray imaging telescope under development at INPE as a pathfinder for the MIRAX (Monitor e Imageador de Raios X) satellite mission. The strategic target was to reuse the SATellite Control System (SATCS), a software framework developed to control and monitor INPÉs satellites, for balloon operation. This paper presents the results of that effort and the new ongoing project, a computer-based framework named I2Bso, which strategic target is to Integrate INPÉs Balloon and Satellite Operation data centers. The I2Bso major purpose is to support the continuous assessment of an innovative technology after different qualification flights either on board balloons or satellites in order to acquire growing evidence for the technology maturity.

  4. SpaceWire model development technology for satellite architecture.

    Energy Technology Data Exchange (ETDEWEB)

    Eldridge, John M.; Leemaster, Jacob Edward; Van Leeuwen, Brian P.

    2011-09-01

    Packet switched data communications networks that use distributed processing architectures have the potential to simplify the design and development of new, increasingly more sophisticated satellite payloads. In addition, the use of reconfigurable logic may reduce the amount of redundant hardware required in space-based applications without sacrificing reliability. These concepts were studied using software modeling and simulation, and the results are presented in this report. Models of the commercially available, packet switched data interconnect SpaceWire protocol were developed and used to create network simulations of data networks containing reconfigurable logic with traffic flows for timing system distribution.

  5. Transfer of satellite applications and technology - The need for a U.S. initiative

    Science.gov (United States)

    Hudson, Heather E.

    In the brief history of satellite communications, the United States has passed through three major eras: the Era of Conjecture, the Era of Experiments and the Era of Services. NASA took the lead in the experimental era to demonstrate both technology and applications - and to ensure their transfer for commercial use. The developing world has also entered the Era of Services, but without the benefit of an experimental phase. Several developing countries now have their own domestic systems; others share regqional systems or lease domestic capacity from INTELSAT. However, the record of developmental applications of these satellites has been disappointing to date. Much capacity sits idle. The U.S. has a great deal to share with the developing world to assist in the effective utilization of this technology. A U.S. Satellite Applications and Technology Transfer (SATT) program is proposed.

  6. TARGET SELECTION FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT (APOGEE)

    Energy Technology Data Exchange (ETDEWEB)

    Zasowski, G.; Johnson, Jennifer A.; Andrews, B.; Epstein, C. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States); Frinchaboy, P. M.; Jackson, K. [Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Majewski, S. R.; Chojnowski, S. D.; Skrutskie, M. F.; Beaton, R. L. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Nidever, D. L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Pinto, H. J. Rocha; Girardi, L. [Laboratorio Interinstitucional de e-Astronomia-LIneA, Rio de Janeiro, RJ 20921-400 (Brazil); Cudworth, K. M. [Yerkes Observatory, University of Chicago, Williams Bay, WI 53191 (United States); Munn, J. [US Naval Observatory, Flagstaff Station, Flagstaff, AZ 86001 (United States); Blake, C. H. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Covey, K. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Deshpande, R.; Fleming, S. W. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Fabbian, D., E-mail: gail.zasowski@gmail.com [Instituto de Astrofisica de Canarias, Calle Via Lactea s/n, E-38205 La Laguna, Tenerife (Spain); and others

    2013-10-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution infrared spectroscopic survey spanning all Galactic environments (i.e., bulge, disk, and halo), with the principal goal of constraining dynamical and chemical evolution models of the Milky Way. APOGEE takes advantage of the reduced effects of extinction at infrared wavelengths to observe the inner Galaxy and bulge at an unprecedented level of detail. The survey's broad spatial and wavelength coverage enables users of APOGEE data to address numerous Galactic structure and stellar populations issues. In this paper we describe the APOGEE targeting scheme and document its various target classes to provide the necessary background and reference information to analyze samples of APOGEE data with awareness of the imposed selection criteria and resulting sample properties. APOGEE's primary sample consists of {approx}10{sup 5} red giant stars, selected to minimize observational biases in age and metallicity. We present the methodology and considerations that drive the selection of this sample and evaluate the accuracy, efficiency, and caveats of the selection and sampling algorithms. We also describe additional target classes that contribute to the APOGEE sample, including numerous ancillary science programs, and we outline the targeting data that will be included in the public data releases.

  7. Chemical trends in the Galactic Halo with APOGEE data

    CERN Document Server

    Fernández-Alvar, E; Prieto, C Allende; Hayden, M R; Beers, T C; Fernández-Trincado, J G; Meza, A; Schultheis, M; Santiago, B X; Queiroz, A B; Anders, F; da Costa, L N; Chiappini, C

    2016-01-01

    The galaxy formation process in the $\\Lambda$-Cold Dark Matter scenario can be constrained from the analysis of stars in the Milky Way's halo system. We examine the variation of chemical abundances in distant halo stars observed by the Apache Point Galactic Evolution Experiment (APOGEE), as a function of distance from the Galactic center ($r$) and iron abundance ([M/H]), in the range 5 $\\lesssim r \\lesssim$ 30 kpc and $-2.5 15$ kpc and [M/H] $> -1.1$ (larger in the case of O, Mg and S) with respect to the nearest halo stars. This result confirms previous claims for low-$\\alpha$ stars found at larger distances. Chemical differences in elements with other nucleosynthetic origins (Ni, K, Na, and Al) are also detected. C and N do not provide reliable information about the interstellar medium from which stars formed because our sample comprises RGB and AGB stars and can experience mixing of material to their surfaces.

  8. Advanced technology for a satellite multichannel demultiplexer/demodulator

    Science.gov (United States)

    Abramovitz, Irwin J.; Flechsig, Drew E.; Matteis, Richard M., Jr.

    1994-01-01

    Satellite on-board processing is needed to efficiently service multiple users while at the same time minimizing earth station complexity. The processing satellite receives a wideband uplink at 30 GHz and down-converts it to a suitable intermediate frequency. A multichannel demultiplexer then separates the composite signal into discrete channels. Each channel is then demodulated by bulk demodulators, with the baseband signals routed to the downlink processor for retransmission to the receiving earth stations. This type of processing circumvents many of the difficulties associated with traditional bent-pipe repeater satellites. Uplink signal distortion and interference are not retransmitted on the downlink. Downlink power can be allocated in accordance with user needs, independent of uplink transmissions. This allows the uplink users to employ different data rates as well as different modulation and coding schemes. In addition, all downlink users have a common frequency standard and symbol clock on the satellite, which is useful for network synchronization in time division multiple access schemes. The purpose of this program is to demonstrate the concept of an optically implemented multichannel demultiplexer (MCD). A proof-of-concept (POC) model has been developed which has the ability to receive a 40 MHz wide composite signal consisting of up to 1000 40 kHz QPSK modulated channels and perform the demultiplexing process. In addition a set of special test equipment (STE) has been configured to evaluate the performance of the POC model. The optical MCD is realized as an acousto-optic spectrum analyzer utilizing the capability of Bragg cells to perform the required channelization. These Bragg cells receive an optical input from a laser source and an RF input (the signal). The Bragg interaction causes optical output diffractions at angles proportional to the RF input frequency. These discrete diffractions are optically detected and output to individual demodulators for

  9. Determining Ages of APOGEE Giants with Known Distances

    Science.gov (United States)

    Feuillet, Diane K.; Bovy, Jo; Holtzman, Jon; Girardi, Léo; MacDonald, Nick; Majewski, Steven R.; Nidever, David L.

    2016-01-01

    We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R ˜ 22,500), near infrared (1.51-1.7 μm) APOGEE spectra provide measurements of stellar atmospheric parameters (temperature, surface gravity, [M/H], and [α/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 30%. For giants, the relatively rapid evolution up the red giant branch allows the age to be constrained by the mass. We examine methods of estimating age using both the mass-age relation directly and a Bayesian isochrone matching of measured parameters, assuming a constant SFH. To improve the SFH prior, we use a hierarchical modeling approach to constrain the parameters of the model SFH using the age probability distribution functions of the data. The results of an α-dependent Gaussian SFH model show a clear age-[α/M] relation at all ages. Using this SFH model as the prior for an empirical Bayesian analysis, we determine ages for individual stars. The resulting age-metallicity relation is flat, with a slight decrease in [M/H] at the oldest ages and a ˜0.5 dex spread in metallicity across most ages. For stars with ages ≲1 Gyr we find a smaller spread, consistent with radial migration having a smaller effect on these young stars than on the older stars.

  10. DETERMINING AGES OF APOGEE GIANTS WITH KNOWN DISTANCES

    Energy Technology Data Exchange (ETDEWEB)

    Feuillet, Diane K.; Holtzman, Jon [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Bovy, Jo [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Girardi, Léo [Osservatorio Astronomico di Padova—INAF, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); MacDonald, Nick [Department of Astronomy, University of Washington, Seattle, WA 98195 (United States); Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Nidever, David L., E-mail: feuilldk@nmsu.edu [Large Synoptic Survey Telescope, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

    2016-01-20

    We present a sample of 705 local giant stars observed using the New Mexico State University 1 m telescope with the Sloan Digital Sky Survey-III/Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph, for which we estimate stellar ages and the local star formation history (SFH). The high-resolution (R ∼ 22,500), near infrared (1.51–1.7 μm) APOGEE spectra provide measurements of stellar atmospheric parameters (temperature, surface gravity, [M/H], and [α/M]). Due to the smaller uncertainties in surface gravity possible with high-resolution spectra and accurate Hipparcos distance measurements, we are able to calculate the stellar masses to within 30%. For giants, the relatively rapid evolution up the red giant branch allows the age to be constrained by the mass. We examine methods of estimating age using both the mass–age relation directly and a Bayesian isochrone matching of measured parameters, assuming a constant SFH. To improve the SFH prior, we use a hierarchical modeling approach to constrain the parameters of the model SFH using the age probability distribution functions of the data. The results of an α-dependent Gaussian SFH model show a clear age–[α/M] relation at all ages. Using this SFH model as the prior for an empirical Bayesian analysis, we determine ages for individual stars. The resulting age–metallicity relation is flat, with a slight decrease in [M/H] at the oldest ages and a ∼0.5 dex spread in metallicity across most ages. For stars with ages ≲1 Gyr we find a smaller spread, consistent with radial migration having a smaller effect on these young stars than on the older stars.

  11. Potential Market for Satellite Technology in Meeting Telecommunication Needs of Developing Nations

    Science.gov (United States)

    1996-01-01

    A recent study examined the potential for satellite technology to meet the telecommunication needs of developing nations. The growth of these nations depends on their attracting and holding the industrial investments of developed nations. This will not be likely with the antiquated telecommunications infrastructure typical of developing nations. On the contrary, it will require an infrastructure that is compatible with international standards. Most of the developing nations perceive this necessity and are pursuing the necessary upgrades. The rate of replacement, types of technology, services affected, and the terrestrial/satellite mix differ by each nation's priorities and gross national product (GNP).

  12. CONTACT: An Air Force technical report on military satellite control technology

    Science.gov (United States)

    Weakley, Christopher K.

    1993-07-01

    This technical report focuses on Military Satellite Control Technologies and their application to the Air Force Satellite Control Network (AFSCN). This report is a compilation of articles that provide an overview of the AFSCN and the Advanced Technology Program, and discusses relevant technical issues and developments applicable to the AFSCN. Among the topics covered are articles on Future Technology Projections; Future AFSCN Topologies; Modeling of the AFSCN; Wide Area Communications Technology Evolution; Automating AFSCN Resource Scheduling; Health & Status Monitoring at Remote Tracking Stations; Software Metrics and Tools for Measuring AFSCN Software Performance; Human-Computer Interface Working Group; Trusted Systems Workshop; and the University Technical Interaction Program. In addition, Key Technology Area points of contact are listed in the report.

  13. Calibration/Validation Technology for the CO2 Satellite Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We are proposing to develop high altitude CO2 analyzer technology that can be deployed on the research aircraft of NASA's Airborne Science Program (ASP). The...

  14. Fast, Affordable, Science and Technology Satellite (FASTSAT) Huntsville-01 (HSV-01) Spacecraft Lessons Learned Report

    Science.gov (United States)

    Smith, Timothy A.

    2012-01-01

    The Fast Affordable Science and Technology Satellite (FASTSAT) project is a path finding effort to produce reliable satellite busses for different applications at an unprecedented speed and low cost. The project is designed to be a generational project and the first satellite produced is the Huntsville -01 (HSV-01) spacecraft. The subject of this report is the lessons learned gained during the development, testing, and up to the delivery of the FASTSAT HSV -01 spacecraft. The purpose of this report is to capture the major findings that will greatly benefit the future FASTSAT satellites and perhaps other projects interested in pushing the boundaries for cost and schedule. The FASTSAT HSV -01 primary objectives, success criteria, and team partners are summarized to give a frame of reference to the lessons learned.

  15. Summary of the CTS Transient Event Counter data after one year of operation. [Communication Technology Satellite

    Science.gov (United States)

    Stevens, N. J.; Klinect, V. W.; Gore, J. V.

    1977-01-01

    The environmental charging of satellite surfaces during geomagnetic substorms is the apparent cause of a significant number of anomalous events occurring on geosynchronous satellites since the early 1970's. Electromagnetic pulses produced in connection with the differential charging of insulators can couple into the spacecraft harness and cause electronic switching anomalies. An investigation conducted to determine the response of the spacecraft surfaces to substorm particle fluxes makes use of a harness transient detector. The harness transient detector, called the Transient Event Counter (TEC) was built and integrated into the Canadian-American Communications Technology Satellite (CTS). A description of the TEC and its operational characteristics is given and the obtained data are discussed. The data show that the satellite surfaces appear to be charged to the point that discharges occur and that the discharge-induced transients couple into the wire harnesses.

  16. System Critical Design Audit (CDA). Books 1, 2 and 3; [Small Satellite Technology Initiative (SSTI Lewis Spacecraft Program)

    Science.gov (United States)

    1995-01-01

    Small Satellite Technology Initiative (SSTI) Lewis Spacecraft Program is evaluated. Spacecraft integration, test, launch, and spacecraft bus are discussed. Payloads and technology demonstrations are presented. Mission data management system and ground segment are also addressed.

  17. Communication Media and Educational Technology: An Overview and Assessment with Reference to Communication Satellites.

    Science.gov (United States)

    Ohlman, Herbert

    In this survey and analysis of the present state and future trends of communication media and educational technology, particular emphasis is placed on the potential uses of communication satellites and the substitution of electronic transmission for physical distribution of educational materials. The author analyzes in detail the characteristics…

  18. MISAT : Designing a Series of Powerful Small Satellites Based upon Micro Systems Technology

    NARCIS (Netherlands)

    Gill, E.; Monna, G.L.E.; Scherpen, J.M.A.; Verhoeven, C.J.M.

    2007-01-01

    MISAT is a research and development cluster which will create a small satellite platform based on Micro Systems Technology (MST) aiming at innovative space as well as terrestrial applications. MISAT is part of the Dutch MicroNed program which has established a microsystems infrastructure to fully

  19. MISAT : Designing a Series of Powerful Small Satellites Based upon Micro Systems Technology

    NARCIS (Netherlands)

    Gill, E.; Monna, G.L.E.; Scherpen, J.M.A.; Verhoeven, C.J.M.

    2007-01-01

    MISAT is a research and development cluster which will create a small satellite platform based on Micro Systems Technology (MST) aiming at innovative space as well as terrestrial applications. MISAT is part of the Dutch MicroNed program which has established a microsystems infrastructure to fully ex

  20. Extremely high frequency (EHF) satellite communications (SATCOM) technology-transmitters and receivers

    Science.gov (United States)

    Raue, Jorg E.

    1983-10-01

    During the past three years, interest in satellite communications in the frequency bands above Ku-band has expanded dramatically. As a result, a number of key technology developments, targeted to meet specific next generation spaceborne needs, were undertaken. The state-of-the-art in solid state power transmitters and low noise receivers, including critical passive component technology, is presented. This includes filters as well as a series of rugged high performance ferrite components such as isolators, circulators and latching switches.

  1. VizieR Online Data Catalog: ASPCAP weights for the 15 APOGEE chemical elements (Garcia+, 2016)

    Science.gov (United States)

    Garcia Perez, A. E.; Allende Prieto, C.; Holtzman, J. A.; Shetrone, M.; Meszaros, S.; Bizyaev, D.; Carrera, R.; Cunha, K.; Garcia-Hernandez, D. A.; Johnson, J. A.; Majewski, S. R.; Nidever, D. L.; Schiavon, R. P.; Shane, N.; Smith, V. V.; Sobeck, J.; Troup, N.; Zamora, O.; Weinberg, D. H.; Bovy, J.; Eisenstein, D. J.; Feuillet, D.; Frinchaboy, P. M.; Hayden, M. R.; Hearty, F. R.; Nguyen, D. C.; O'Connell, R. W.; Pinsonneault, M. H.; Wilson, J. C.; Zasowski, G.

    2016-07-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R~22500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. The pipeline matches the observations to a set of synthetic spectrum templates using the {chi}2 minimization in a multidimensional parameter space. Stellar parameters are derived first from the entire APOGEE spectral range, followed by the determination of individual chemical abundances from spectral windows optimized for each element. Table3 gives the weights as a function of wavelength, for the 15 APOGEE chemical elements. (1 data file).

  2. Downsizing Antenna Technologies for Mobile and Satellite Communications

    Science.gov (United States)

    Huang, J.; Densmore, A.; Tulintseff, A.; Jamnejad, V.

    1993-01-01

    Due to the increasing and stringent functional requirements (larger capacity, longer distances, etc.) of modern day communication systems, higher antenna gains are generally needed. This higher gain implies larger antenna size and mass which are undesirable to many systems. Consequently, downsizing antenna technology becomes one of the most critical areas for research and development efforts. Techniques to reduce antenna size can be categorized and are briefly discussed.

  3. The peculiar globular cluster Palomar 1 and persistence in the SDSS-APOGEE data base

    Science.gov (United States)

    Jahandar, Farbod; Venn, Kim A.; Shetrone, Matthew D.; Irwin, Mike; Bovy, Jo; Sakari, Charli M.; Kielty, Collin L.; Digby, Ruth A. R.; Frinchaboy, Peter M.

    2017-10-01

    The Sloan Digital Sky Survey-III Apache Point Observatory Galactic Evolution Experiment (APOGEE) Data Release 12 (DR12) is a unique resource to search for stars beyond the tidal radii of star clusters. We have examined the APOGEE DR12 data base for new candidates of the young star cluster Palomar 1 (Pal 1), a system with previously reported tidal tails (Niederste-Ostholt et al. 2010). The APOGEE Stellar Parameters and Chemical Abundances Pipeline data base includes spectra and stellar parameters for two known members of Pal 1 (Stars I and II), however these do not agree with the stellar parameters determined from optical spectra by Sakari et al. (2011). We find that the APOGEE analysis of these two stars is strongly affected by the known persistence problem (Majewski et al. 2015; Nidever et al. 2015). By re-examining the individual visits, and removing the blue (and sometimes green) APOGEE detector spectra affected by persistence, then we find excellent agreement in a re-analysis of the combined spectra. These methods are applied to another five stars in the APOGEE field with similar radial velocities and metallicities as those of Pal 1. Only one of these new candidates, Star F, may be a member located in the tidal tail based on its heliocentric radial velocity, metallicity and chemistry. The other four candidates are not well aligned with the tidal tails, and comparison to the Besançon model (Robin et al. 2003) suggests that they are more likely to be non-members, i.e. part of the Galactic halo. This APOGEE field could be re-examined for other new candidates if the persistence problem can be removed from the APOGEE spectral data base.

  4. VizieR Online Data Catalog: SDSS-III/APOGEE. II. The multi-epoch ABE sample (Chojnowski+, 2017)

    Science.gov (United States)

    Chojnowski, S. D.; Wisniewski, J. P.; Whelan, D. G.; Labadie-Bartz, J.; Borges Fernandes, M.; Lin, C.-C.; Majewski, S. R.; Stringfellow, G. S.; Mennickent, R. E.; Roman-Lopes, A.; Tang, B.; Hearty, F. R.; Holtzman, J. A.; Pepper, J.; Zasowski, G.

    2017-08-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) instrument is a 300-fiber spectrograph that records most of the H band with resolving power R~22500 on three non-overlapping detectors (blue detector: 15145-15810Å, green detector: 15860-16430Å, red detector: 16480-16950Å). The SDSS-IV/APOGEE-2 survey began operations on the 2.5m Sloan telescope starting in 2014 August. Although numerous new Be stars have been identified in the APOGEE-2 telluric standard star sample, in this paper we only use APOGEE-2 spectra pertaining to Be stars that are also observed during SDSS-III/APOGEE-1 and again selected as telluric standards for APOGEE-2 observations. In particular, the following stars have been observed during APOGEE-1 and APOGEE-2, with the number of APOGEE-2 observations given in parentheses: ABE-038 (1), ABE-051 (1), ABE-054 (6), ABE-074 (15), ABE-093 (6), ABE-101 (5), ABE-148 (1), ABE-167 (4), ABE-176 (6), ABE-177 (6), ABE-184 (6), ABE-185 (6), ABE-187 (7), ABE-188 (7), and ABE-190 (7). After rejecting (1) spectra with S/N<40, (2) spectra mentioned in Section 2.1.2, and (3) 16 stars with only one APOGEE observation, we arrive at a total of 1100 spectra for 213 stars in this paper (more than five spectra per star on average). (3 data files).

  5. CTS digital video college curriculum-sharing experiment. [Communications Technology Satellite

    Science.gov (United States)

    Lumb, D. R.; Sites, M. J.

    1974-01-01

    NASA-Ames Research Center, Stanford University, and Carleton University, Ottawa, Canada, are participating in a joint experiment to evaluate the feasibility and effectiveness of college curriculum sharing using compressed digital television and the Communications Technology Satellite (CTS). Each university will offer televised courses to the other during the 1976-1977 academic year via CTS, a joint program by NASA and the Canadian Department of Communications. The video compression techniques to be demonstrated will enable economical interconnection of educational institutions using existing and planned domestic satellites.

  6. Advanced Communications Technology Satellite (ACTS). Phase 1: Industrial/academic experimenters

    Science.gov (United States)

    Maisel, James E.; Nowlin, Robert W.

    1992-01-01

    This report presents the work done at Arizona State University under the ACTS Experimenters Program. The main thrust of the Program was to develop experiments to test, evaluate, and prove the commercial worthiness of the ACTS satellite which is scheduled for launch in 1993. To accomplish this goal, meetings were held with various governmental, industrial, and academic units to discuss the ACTS satellite and its technology and possible experiments that would generate industrial interest and support for ASU's efforts. Several local industries generated several experiments of their own. The investigators submitted several experiments of educational, medical, commercial, and technical value and interest. The disposition of these experimental proposals is discussed in this report.

  7. Pre-Launch Radiometric Performance Characterization of the Advanced Technology Microwave Sounder on the Joint Polar Satellite System-1 Satellite

    Science.gov (United States)

    Smith, Craig K.; Kim, Edward; Leslie, R. Vincent; Lyu, Joseph; McCormick, Lisa M.; Anderson, Kent

    2017-01-01

    The Advanced Technology Microwave Sounder (ATMS) is a space-based, cross-track radiometer for operational atmospheric temperature and humidity sounding, utilizing 22 channels over a frequency range from 23 to 183 gigahertz. The ATMS for the Joint Polar Satellite System-1 has undergone two rounds of re-work in 2014-2015 and 2016, following performance issues discovered during and following thermal vacuum chamber (TVAC) testing at the instrument and observatory level. Final shelf-level testing, including measurement of pass band characteristics and spectral response functions, was completed in December 2016. Final instrument-level TVAC testing and calibration occurred during February 2017. Here we will describe the instrument-level TVAC calibration process, and illustrate with results from the final TVAC calibration effort.

  8. Cardinal kinematics: I. Rotation fields of the APOGEE Survey

    CERN Document Server

    Kordopatis, Georges; Chiappini, Cristina; Minchev, Ivan; Anders, Friedrich; Santiago, Basilio

    2016-01-01

    Correlations between stellar chemistry and kinematics have long been used to gain insight into the evolution of the Milky Way Galaxy. Orbital angular momentum is a key physical parameter and it is often estimated from three-dimensional space motions. We here demonstrate the lower uncertainties that can be achieved in the estimation of one component of velocity through selection of stars in key directions and use of line-of-sight velocity alone (i.e. without incorporation of proper motion data). In this first paper we apply our technique to stars observed in the direction of Galactic rotation in the APOGEE survey. We first derive the distribution of azimuthal velocities, $v_\\phi$, then from these and observed radial coordinates, estimate the stellar guiding centre radii, $R_g$, within $6.9\\leq R \\leq 10$ kpc with uncertainties smaller than (or of the order of) 1kpc. We show that there is no simple way to select a clean stellar sample based on low errors on proper motions and distances to obtain high-quality 3D...

  9. Chemical trends in the Galactic halo from APOGEE data

    Science.gov (United States)

    Fernández-Alvar, E.; Carigi, L.; Allende Prieto, C.; Hayden, M. R.; Beers, T. C.; Fernández-Trincado, J. G.; Meza, A.; Schultheis, M.; Santiago, B. X.; Queiroz, A. B.; Anders, F.; da Costa, L. N.; Chiappini, C.

    2017-02-01

    The galaxy formation process in the Λ cold dark matter scenario can be constrained from the analysis of stars in the Milky Way's halo system. We examine the variation of chemical abundances in distant halo stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE), as a function of distance from the Galactic Centre (r) and iron abundance ([M/H]), in the range 5 ≲ r ≲ 30 kpc and -2.5 distribution function exhibits two peaks, at [M/H] ∼ -1.5 and ∼-2.1, consistent with previously reported halo metallicity distributions. We obtain a difference of ∼0.1 dex for α-element-to-iron ratios for stars at r > 15 kpc and [M/H] > -1.1 (larger in the case of O, Mg, and S) with respect to the nearest halo stars. This result confirms previous claims for low-α stars found at larger distances. Chemical differences in elements with other nucleosynthetic origins (Ni, K, Na, and Al) are also detected. C and N do not provide reliable information about the interstellar medium from which stars formed because our sample comprises red giant branch and asymptotic giant branch stars and can experience mixing of material to their surfaces.

  10. A Report on University Applications of Satellite/Cable Technology; First Annual International Communications Conference (Madison, Wisconsin, June 3-5, 1975).

    Science.gov (United States)

    Parker, Lorne A., Comp.; Riccomini, Betsy, Comp.

    The aim of the conference on University Applications of Satellite/Cable Technology was to stimulate discussion among universities, industry, and government on the possibilities of satellite and cable technology in the future. Twenty-six presentations were made covering the following topics: the current status of satellite/cable technology; the…

  11. Satellite Technology as a Source of Integration. A Comparative Analyze: Europe MERCOSUR

    Science.gov (United States)

    Castillo Argañarás, Luis F.

    2002-01-01

    Satellite technology as a source of integration. A comparative several changes in the field of international law, creating the need to build a new framework for integration and cooperation. analysis between the development of the European Integration for space activities and the first steps towards the same target by the MERCOSUR with a comparative point of view will show the positive and negative side effects of its development up to our present time.

  12. Cardinal kinematics - I. Rotation fields of the APOGEE survey

    Science.gov (United States)

    Kordopatis, Georges; Wyse, Rosemary F. G.; Chiappini, Cristina; Minchev, Ivan; Anders, Friedrich; Santiago, Basilio

    2017-05-01

    Correlations between stellar chemistry and kinematics have long been used to gain insight into the evolution of the Milky Way Galaxy. Orbital angular momentum is a key physical parameter and it is often estimated from three-dimensional space motions. We here demonstrate the lower uncertainties that can be achieved in the estimation of one component of velocity through selection of stars in key directions and use of line-of-sight velocity alone (i.e. without incorporation of proper motion data). In this first paper, we apply our technique to stars observed in the direction of Galactic rotation in the APOGEE (Apache Point Observatory Galactic Evolution Experiment) survey. We first derive the distribution of azimuthal velocities, vϕ, then from these and observed radial coordinates, estimate the stellar guiding centre radii, Rg, within 6.9 ≤ R ≤ 10 kpc with uncertainties smaller than (or of the order of) 1 kpc. We show that there is no simple way to select a clean stellar sample based on low errors on proper motions and distances to obtain high-quality 3D velocities and hence one should pay particular attention when trying to identify kinematically peculiar stars based on velocities derived using the proper motions. Using our vϕ estimations, we investigate the joint distribution of elemental abundances and rotational kinematics free from the blurring effects of epicyclic motions, and we derive the ∂vϕ/∂[α/Fe] and ∂vϕ/∂[Fe/H] trends for the thin and thick discs as a function of radius. Our analysis provides further evidence for radial migration within the thin disc and hints against radial migration playing a significant role in the evolution of the thick disc.

  13. Cardinal kinematics: I. Rotation fields of the APOGEE Survey

    Science.gov (United States)

    Kordopatis, Georges; Wyse, Rosemary F. G.; Chiappini, Cristina; Minchev, Ivan; Anders, Friedrich; Santiago, Basilio

    2017-01-01

    Correlations between stellar chemistry and kinematics have long been used to gain insight into the evolution of the Milky Way Galaxy. Orbital angular momentum is a key physical parameter and it is often estimated from three-dimensional space motions. We here demonstrate the lower uncertainties that can be achieved in the estimation of one component of velocity through selection of stars in key directions and use of line-of-sight velocity alone (i.e. without incorporation of proper motion data). In this first paper we apply our technique to stars observed in the direction of Galactic rotation in the APOGEE survey. We first derive the distribution of azimuthal velocities, vφ, then from these and observed radial coordinates, estimate the stellar guiding centre radii, Rg, within 6.9 ≤ R ≤ 10 kpc with uncertainties smaller than (or of the order of) 1 kpc. We show that there is no simple way to select a clean stellar sample based on low errors on proper motions and distances to obtain high-quality 3D velocities and hence one should pay particular attention when trying to identify kinematically peculiar stars based on velocities derived using the proper motions. Using our vφ estimations, we investigate the joint distribution of elemental abundances and rotational kinematics free from the blurring effects of epicyclic motions, and we derive the partial v_φ / partial [α /Fe] & ∂vφ/∂[Fe/H] trends for the thin and thick discs as a function of radius. Our analysis provides further evidence for radial migration within the thin disc and hints against radial migration playing a significant role in the evolution of the thick disc.

  14. Cubic Satellites, Vanguard Technology Integration, an Educational Opportunity of Modernization in Mexico

    Science.gov (United States)

    Moreno-Franco, Olmo A.; Muñoz-Ubando, L. A.; Moreno-Moreno, Prudenciano; Vargas-Méndez, Eduardo E.

    This paper provides a theoretical approach on the CubeSat standard making a cost-benefit analysis in the use of pico-satellites at the education and technology integration model for educational modernization. With the CubeSat format is planned to develop an orbit LEO pico-satellite as part of a multidisciplinary project led by the Robotics Institute of Yucatan (TRIY), assisted with previous experience in Mexico and Colombia, to build a satellite capable of stabilizing through a robotic device, which will be a training model for human resources in Mexico. The CubeSat initiative represents a technological development of more than 10 years who is still alive and growing, attracting new participants from different educational institutions and global business, which has proven to be a project that would be made and successful results with a significant low budget compared to other space missions, and finally is an opportunity to bring students and teachers to the aerospace industry, through a convergence of technology, and academic discipline.

  15. Two for the Price of One: SB2s in the SDSS-III/APOGEE Survey

    Science.gov (United States)

    Chojnowski, S. Drew; Nguyen, Duy Cuong; Nidever, David L.; Zasowski, Gail; Bender, Chad F.; Troup, Nicholas William; Beers, Timothy C.; de Lee, Nathan M.; Fleming, Scott W.; Frinchaboy, Peter M.; García Pérez, Ana; Hearty, Fred R.; Holtzman, Jon A.; Majewski, Steven R.; Schiavon, Ricardo P.; Apogee Team

    2015-01-01

    We present a catalog of double-lined spectroscopic binaries (SB2s) identified in H-band spectra from the SDSS-III Apache Point Galactic Evolution Experiment (APOGEE). The APOGEE survey utilizes high-resolution, high-signal-to-noise, multi-epoch, H-band spectra of primarily red giant branch stars to study the chemical and dynamical history of the Milky Way Galaxy. In order to identify the SB2 sample, we searched the data for double and triple peaks in the radial velocity cross-correlation functions (RVCCF) obtained through comparison of the observed spectra to synthetic template spectra covering a wide range of stellar parameters. We also consider the singular value decomposition (SVD) method to derive line broadening profiles and search for SB2s. The SB2 identification algorithm will be applied to all data from the APOGEE-2 survey so that SB2 systems are automatically flagged. APOGEE's multi-epoch spectroscopy of SB2s yields dynamically measured mass ratios and, in the case of eclipsing systems, facilitates determination of the true masses and radii. Results for some of the more remarkable SB2 systems will be presented, as will statistics with respect to the SB2 fraction in a large spectroscopic survey like APOGEE.

  16. THE SDSS-III APOGEE SPECTRAL LINE LIST FOR H-BAND SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Shetrone, M. [University of Texas at Austin, McDonald Observatory (United States); Bizyaev, D.; Chojnowski, D. [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Lawler, J. E. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, WI 53706 (United States); Prieto, C. Allende; Zamora, O.; García-Hernández, D. A.; Souto, D. [Instituto de Astrofísica de Canarias, Calle Vía Lactea s/n, E-38205 La Laguna, Tenerife (Spain); Johnson, J. A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Smith, V. V. [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Cunha, K. [Observatório Nacional, Rua General Jose Cristino, 77, 20921-400 São Cristóvão, Rio de Janeiro, RJ (Brazil); Holtzman, J. [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Pérez, A. E. García; Sobeck, J.; Majewski, S. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Mészáros, Sz. [ELTE Gothard Astrophysical Observatory, H-9704 Szombathely, Szent Imre herceg st. 112 (Hungary); Koesterke, L. [The University of Texas at Austin, Texas Advanced Computing Center (United States); Zasowski, G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2015-12-15

    We present the H-band spectral line lists adopted by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). The APOGEE line lists comprise astrophysical, theoretical, and laboratory sources from the literature, as well as newly evaluated astrophysical oscillator strengths and damping parameters. We discuss the construction of the APOGEE line list, which is one of the critical inputs for the APOGEE Stellar Parameters and Chemical Abundances Pipeline, and present three different versions that have been used at various stages of the project. The methodology for the newly calculated astrophysical line lists is reviewed. The largest of these three line lists contains 134,457 molecular and atomic transitions. In addition to the format adopted to store the data, the line lists are available in MOOG, Synspec, and Turbospectrum formats. The limitations of the line lists along with guidance for its use on different spectral types are discussed. We also present a list of H-band spectral features that are either poorly represented or completely missing in our line list. This list is based on the average of a large number of spectral fit residuals for APOGEE observations spanning a wide range of stellar parameters.

  17. Choice of high-apogee AES orbits on the basis of the qualitative methods of the theory of perturbations and situational analysis. Part I. Situational studies based on orbital tori

    Science.gov (United States)

    Prokhorenko, V. I.

    2016-03-01

    The paper discusses the problems of the choice of high-apogee orbits of artificial Earth satellites (AES), proceeding from the tasks of space experiments aimed at studying near-earth space and taking into account the features of the orbital evolution and ballistic lifetime. The suggested methods of the choice of orbits consist of two components. The first is based on the use of mathematical models of studied regions of near-earth space and various techniques of situation analysis, among which the annual and daily orbital tori developed by the author about 35 years ago are key. The second component is based on qualitative methods of the theory of perturbations of high-apogee AES orbits developed by M.L. Lidov more than 50 years ago.

  18. Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

    Science.gov (United States)

    Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

    1996-01-01

    The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

  19. Preliminary Results of the Ground/Orbiter Lasercomm Demonstration Experiment between Table Mountain and teh ETS-V1 Satellite

    Science.gov (United States)

    Wilson, K. E.; Lesh, J. R.; Araki, K.; Arimoto, Y.

    1996-01-01

    The Ground/Orbiter Lasercomm Demonstration (GOLD) is an optical communications demonstration between the Japanese Engineering Test Satellite (ETS-V1) and an optical ground transmitting and receiving station at the Table Mountain FAcility in Wrightwood California. Laser transmissions to the satellite are performed approximately four hours every third night when the satellite is at apogee above Table Mountain.

  20. Calibrations of Atmospheric Parameters Obtained from the First Year of SDSS-III APOGEE Observations

    CERN Document Server

    Mészáros, Sz; Pérez, A E García; Prieto, C Allende; Schiavon, R P; Basu, S; Bizyaev, D; Chaplin, W J; Chojnowski, S D; Cunha, K; Elsworth, Y; Epstein, C; Frinchaboy, P M; García, R A; Hearty, F R; Hekker, S; Johnson, J A; Kallinger, T; Koesterke, L; Majewski, S R; Martell, S L; Nidever, D; Pinsonneault, M H; O'Connell, J; Shetrone, M; Smith, V V; Wilson, J C; Zasowski, G

    2013-01-01

    The SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three year survey that is collecting 100,000 high-resolution spectra in the near-IR across multiple Galactic populations. To derive stellar parameters and chemical compositions from this massive data set, the APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP) has been developed. Here, we describe empirical calibrations of stellar parameters presented in the first SDSS-III APOGEE data release (DR10). These calibrations were enabled by observations of 559 stars in 20 globular and open clusters. The cluster observations were supplemented by observations of stars in NASA's Kepler field that have well determined surface gravities from asteroseismic analysis. We discuss the accuracy and precision of the derived stellar parameters, considering especially effective temperature, surface gravity, and metallicity; we also briefly discuss the derived results for the abundances of the alpha-elements, carbon, and nitrogen. Ov...

  1. Results of the Apogee-Raising Campaign of the Magnetospheric Multiscale Mission

    Science.gov (United States)

    Williams, Trevor; Ottenstein, Neil; Palmer, Eric J.; Hollister, Jacob

    2017-01-01

    This paper describes the apogee-raising campaign of the Magnetospheric Multiscale mission, where the spacecraft increased their apogee radii from 12 to 25 Earth radii in a total of 98 maneuvers. These maneuvers included an initial formation resize set to spread the spacecraft apart for safety, 32 apogee-raise delta-v maneuvers, their associated slews, four perigee-raise maneuvers and the associated slews, and finally a set of maneuvers to get back into formation. These activities were all accomplished successfully and on schedule with no anomalies, and at a fuel consumption somewhat less than predicted. As a result, MMS was set up ready to carry out in situ studies of magnetic reconnection in the magnetotail, with sufficient fuel remaining for a significant extended mission.

  2. An accurate and self-consistent chemical abundance catalogue for the APOGEE/Kepler sample

    CERN Document Server

    Hawkins, Keith; Jofre, Paula; Gilmore, Gerry; Elsworth, Yvonne; Hekker, Saskia

    2016-01-01

    Context. The APOGEE survey has obtained high-resolution infrared spectra of more than 100,000 stars. Deriving chemical abundances patterns of these stars is paramount to piecing together the structure of the Milky Way. While the derived chemical abundances have been shown to be precise for most stars, some calibration problems have been reported, in particular for more metal- poor stars. Aims. In this paper, we aim to (1) re-determine the chemical abundances of the APOGEE+Kepler stellar sample (APOKASC) with an independent procedure, line list and line selection, and high quality surface gravity information from astroseismology, and (2) extend the abundance catalogue by including abundances that are not currently reported in the most recent APOGEE release (DR12). Methods. We fixed the Teff and log g to those determined using spectrophotometric and asteroseismic techniques, respectively. We made use of the Brussels Automatic Stellar Parameter (BACCHUS) code to derive the metallicity and broadening parameters f...

  3. Satellite navigation—Amazing technology but insidious risk: Why everyone needs to understand space weather

    Science.gov (United States)

    Hapgood, Mike

    2017-04-01

    Global navigation satellite systems (GNSS) are one of the technological wonders of the modern world. Popularly known as satellite navigation, these systems have provided global access to precision location and timing services and have thereby stimulated advances in industry and consumer services, including all forms of transport, telecommunications, financial trading, and even the synchronization of power grids. But this wonderful technology is at risk from natural phenomena in the form of space weather. GNSS signals experience a slight delay as they pass through the ionosphere. This delay varies with space weather conditions and is the most significant source of error for GNSS. Scientific efforts to correct these errors have stimulated billions of dollars of investment in systems that provide accurate correction data for suitably equipped GNSS receivers in a growing number of regions around the world. This accuracy is essential for GNSS use by aircraft and ships. Space weather also provides a further occasional but severe risk to GNSS: an extreme space weather event may deny access to GNSS as ionospheric scintillation scrambles the radio signals from satellites, and rapid ionospheric changes outstrip the ability of error correction systems to supply accurate corrections. It is vital that GNSS users have a backup for such occasions, even if it is only to hunker down and weather the storm.

  4. Renewable Energy SCADA/Training Using NASA's Advanced Technology Communication Satellite

    Science.gov (United States)

    Kalu, A.; Emrich, C.; Ventre, G.; Wilson, W.; Acosta, Roberto (Technical Monitor)

    2000-01-01

    The lack of electrical energy in the rural communities of developing countries is well known, as is the economic unfeasibility of providing much needed energy to these regions via electric grids. Renewable energy (RE) can provide an economic advantage over conventional forms in meeting some of these energy needs. The use of a Supervisory Control and Data Acquisition (SCADA) arrangement via satellite could enable experts at remote locations to provide technical assistance to local trainees while they acquire a measure of proficiency with a newly installed RE system through hands-on training programs using the same communications link. Upon full mastery of the technologies, indigenous personnel could also employ similar SCADA arrangements to remotely monitor and control their constellation of RE systems. Two separate ACTS technology verification experiments (TVEs) have demonstrated that the portability of the Ultra Small Aperture Terminal (USAT) and the versatility of NASA's Advanced Communications Technology Satellite (ACTS), as well as the advantages of Ka band satellites, can be invaluable in providing energy training via distance education (DE), and for implementing renewable energy system SCADA. What has not been tested is the capabilities of these technologies for a simultaneous implementation of renewable energy DE and SCADA. Such concurrent implementations will be useful for preparing trainees in developing countries for their eventual SCADA operations. The project described in this correspondence is the first effort, to our knowledge, in this specific TVE. The setup for this experiment consists of a one-Watt USAT located at Florida Solar Energy Center (FSEC) connected to two satellite modems tuned to different frequencies to establish two duplex ACTS Ka-band communication channels. A short training program on operation and maintenance of the system will be delivered while simultaneously monitoring and controlling the hybrid using the same satellite

  5. Renewable Energy SCADA/Training Using NASA's Advanced Technology Communication Satellite

    Science.gov (United States)

    Kalu, A.; Emrich, C.; Ventre, G.; Wilson, W.; Acosta, Roberto (Technical Monitor)

    2000-01-01

    The lack of electrical energy in the rural communities of developing countries is well known, as is the economic unfeasibility of providing much needed energy to these regions via electric grids. Renewable energy (RE) can provide an economic advantage over conventional forms in meeting some of these energy needs. The use of a Supervisory Control and Data Acquisition (SCADA) arrangement via satellite could enable experts at remote locations to provide technical assistance to local trainees while they acquire a measure of proficiency with a newly installed RE system through hands-on training programs using the same communications link. Upon full mastery of the technologies, indigenous personnel could also employ similar SCADA arrangements to remotely monitor and control their constellation of RE systems. Two separate ACTS technology verification experiments (TVEs) have demonstrated that the portability of the Ultra Small Aperture Terminal (USAT) and the versatility of NASA's Advanced Communications Technology Satellite (ACTS), as well as the advantages of Ka band satellites, can be invaluable in providing energy training via distance education (DE), and for implementing renewable energy system SCADA. What has not been tested is the capabilities of these technologies for a simultaneous implementation of renewable energy DE and SCADA. Such concurrent implementations will be useful for preparing trainees in developing countries for their eventual SCADA operations. The project described in this correspondence is the first effort, to our knowledge, in this specific TVE. The setup for this experiment consists of a one-Watt USAT located at Florida Solar Energy Center (FSEC) connected to two satellite modems tuned to different frequencies to establish two duplex ACTS Ka-band communication channels. A short training program on operation and maintenance of the system will be delivered while simultaneously monitoring and controlling the hybrid using the same satellite

  6. Iodine Propulsion Advantages for Low Cost Mission Applications and the Iodine Satellite (ISAT) Technology Demonstration

    Science.gov (United States)

    Dankanich, John W.; Schumacher, Daniel M.

    2015-01-01

    The NASA Marshall Space Flight Center Science and Technology Office is continuously exploring technology options to increase performance or reduce cost and risk to future NASA missions including science and exploration. Electric propulsion is a prevalent technology known to reduce mission costs by reduction in launch costs and spacecraft mass through increased post launch propulsion performance. The exploration of alternative propellants for electric propulsion continues to be of interest to the community. Iodine testing has demonstrated comparable performance to xenon. However, iodine has a higher storage density resulting in higher ?V capability for volume constrained systems. Iodine's unique properties also allow for unpressurized storage yet sublimation with minimal power requirements to produce required gas flow rates. These characteristics make iodine an ideal propellant for secondary spacecraft. A range of mission have been evaluated with a focus on low-cost applications. Results highlight the potential for significant cost reduction over state of the art. Based on the potential, NASA has been developing the iodine Satellite for a near-term iodine Hall propulsion technology demonstration. Mission applications and progress of the iodine Satellite project are presented.

  7. Guidance, Navigation, and Control Techniques and Technologies for Active Satellite Removal

    Science.gov (United States)

    Ortega Hernando, Guillermo; Erb, Sven; Cropp, Alexander; Voirin, Thomas; Dubois-Matra, Olivier; Rinalducci, Antonio; Visentin, Gianfranco; Innocenti, Luisa; Raposo, Ana

    2013-09-01

    This paper shows an internal feasibility analysis to de- orbit a non-functional satellite of big dimensions by the Technical Directorate of the European Space Agency ESA. The paper focuses specifically on the design of the techniques and technologies for the Guidance, Navigation, and Control (GNC) system of the spacecraft mission that will capture the satellite and ultimately will de-orbit it on a controlled re-entry.The paper explains the guidance strategies to launch, rendezvous, close-approach, and capture the target satellite. The guidance strategy uses chaser manoeuvres, hold points, and collision avoidance trajectories to ensure a safe capture. It also details the guidance profile to de-orbit it in a controlled re-entry.The paper continues with an analysis of the required sensing suite and the navigation algorithms to allow the homing, fly-around, and capture of the target satellite. The emphasis is placed around the design of a system to allow the rendezvous with an un-cooperative target, including the autonomous acquisition of both the orbital elements and the attitude of the target satellite.Analysing the capture phase, the paper provides a trade- off between two selected capture systems: the net and the tentacles. Both are studied from the point of view of the GNC system.The paper analyses as well the advanced algorithms proposed to control the final compound after the capture that will allow the controlled de-orbiting of the assembly in a safe place in the Earth.The paper ends proposing the continuation of this work with the extension to the analysis of the destruction process of the compound in consecutive segments starting from the entry gate to the rupture and break up.

  8. Electric propulsion for satellites and spacecraft: established technologies and novel approaches

    Science.gov (United States)

    Mazouffre, Stéphane

    2016-06-01

    This contribution presents a short review of electric propulsion (EP) technologies for satellites and spacecraft. Electric thrusters, also termed ion or plasma thrusters, deliver a low thrust level compared to their chemical counterparts, but they offer significant advantages for in-space propulsion as energy is uncoupled to the propellant, therefore allowing for large energy densities. Although the development of EP goes back to the 1960s, the technology potential has just begun to be fully exploited because of the increase in the available power aboard spacecraft, as demonstrated by the very recent appearance of all-electric communication satellites. This article first describes the fundamentals of EP: momentum conservation and the ideal rocket equation, specific impulse and thrust, figures of merit and a comparison with chemical propulsion. Subsequently, the influence of the power source type and characteristics on the mission profile is discussed. Plasma thrusters are classically grouped into three categories according to the thrust generation process: electrothermal, electrostatic and electromagnetic devices. The three groups, along with the associated plasma discharge and energy transfer mechanisms, are presented via a discussion of long-standing technologies like arcjet thrusters, magnetoplasmadynamic thrusters, pulsed plasma thrusters and ion engines, as well as Hall thrusters and variants. More advanced concepts and new approaches for performance improvement are discussed afterwards: magnetic shielding and wall-less configurations, negative ion thrusters and plasma acceleration with a magnetic nozzle. Finally, various alternative propellant options are analyzed and possible research paths for the near future are examined.

  9. ACTS (Advanced Communications Technology Satellite) Propagation Experiment: Preprocessing Software User's Manual

    Science.gov (United States)

    Crane, Robert K.; Wang, Xuhe; Westenhaver, David

    1996-01-01

    The preprocessing software manual describes the Actspp program originally developed to observe and diagnose Advanced Communications Technology Satellite (ACTS) propagation terminal/receiver problems. However, it has been quite useful for automating the preprocessing functions needed to convert the terminal output to useful attenuation estimates. Prior to having data acceptable for archival functions, the individual receiver system must be calibrated and the power level shifts caused by ranging tone modulation must be received. Actspp provides three output files: the daylog, the diurnal coefficient file, and the file that contains calibration information.

  10. Variable conductance heat pipe technology. [research project resulting in heat pipe experiment on OAO-3 satellite

    Science.gov (United States)

    Anderson, W. T.; Edwards, D. K.; Eninger, J. E.; Marcus, B. D.

    1974-01-01

    A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included.

  11. A Mobile Communications Space Link Between the Space Shuttle Orbiter and the Advanced Communications Technology Satellite

    Science.gov (United States)

    Fink, Patrick; Arndt, G. D.; Bondyopadhyay, P.; Shaw, Roland

    1994-01-01

    A communications experiment is described as a link between the Space Shuttle Orbiter (SSO) and the Advanced Communications Technology Satellite (ACTS). Breadboarding for this experiment has led to two items with potential for commercial application: a 1-Watt Ka-band amplifier and a Ka-band, circularly polarized microstrip antenna. Results of the hybrid Ka-band amplifier show gain at 30 dB and a saturated output power of 28.5 dBm. A second version comprised of MMIC amplifiers is discussed. Test results of the microstrip antenna subarray show a gain of approximately 13 dB and excellent circular polarization.

  12. Space situational awareness satellites and ground based radiation counting and imaging detector technology

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Frank, E-mail: frank.jansen@dlr.de [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Behrens, Joerg [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Pospisil, Stanislav [Czech Technical University, IEAP, 12800 Prague 2, Horska 3a/22 (Czech Republic); Kudela, Karel [Slovak Academy of Sciences, IEP, 04001 Kosice, Watsonova 47 (Slovakia)

    2011-05-15

    We review the current status from the scientific and technological point of view of solar energetic particles, solar and galactic cosmic ray measurements as well as high energy UV-, X- and gamma-ray imaging of the Sun. These particles and electromagnetic data are an important tool for space situational awareness (SSA) aspects like space weather storm predictions to avoid failures in space, air and ground based technological systems. Real time data acquisition, position and energy sensitive imaging are demanded by the international space weather forecast services. We present how newly developed, highly miniaturized radiation detectors can find application in space in view of future SSA related satellites as a novel space application due to their counting and imaging capabilities.

  13. The Use of Satellite Technologies for Maritime Surveillance: An Overview of EU Initiatives

    Directory of Open Access Journals (Sweden)

    Ruxandra-Laura BOSILCA

    2016-03-01

    Full Text Available The sea lies at the heart of the EU prosperity and security: the Union and its member states depend on open and secure seas and oceans for their trade, transportation, energy, food, mineral resources, tourism, and a healthy marine environment. Maritime surveillance constitutes a key enabler for safeguarding the EU strategic interests at sea, by providing vital information on developments over, on and under the sea surface and coastal areas. A fundamental role in the process of collecting and communicating relevant information is held by satellite technologies which open paths to cost-effective and innovative alternatives to traditional surveillance techniques. The article proceeds as follows. The first section briefly outlines the key importance of the sea for the economic, military, energy, food, environmental, health, and cultural dimensions of EU security. Then, the concept of “maritime surveillance” is explained within the broader context of maritime security in the following section. In order to explore the use of satellite technologies in the EU maritime surveillance mechanisms, the third section of the paper examines three cases related to: the vessel monitoring system (VMS and the vessel detection system (VDS; FRONTEX, the EU agency for external borders management, and the related framework of EUROSUR; and finally, the CleanSeaNet oil spill monitoring system developed by the European Maritime Safety Agency (EMSA. Lastly, the concluding section summarizes the main findings of the article.

  14. Searching for Long-Period Companions and False Positives within the APOGEE Catalog of Companion Candidates

    Science.gov (United States)

    Nguyen, Duy; Troup, Nicholas William; Majewski, Steven R.

    2017-01-01

    The Sloan Digital Sky Survey (SDSS) Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a large-scale, high-resolution, H-band, spectroscopic survey that has acquired high S/N spectra of 146,000 stars distributed across the Galactic bulge, disk, and halo with a radial velocity (RV) precision of ~100 m/s. We follow up stellar companion detections from the APOGEE DR12 catalog of 382 total APOGEE-identified companions, of which 376 are previously unknown companion candidates. The APOGEE team strives not only to continue expanding the census of extrasolar companions, but also to confirm and characterize our RV detections through a variety of means.We present findings from our investigation of the Kozai mechanism, which explains the development of close-orbiting binaries through an ejected third companion. To do so, we are undertaking a targeted search for long-period companions with hopes to provide further evidence for the Kozai mechanism. This hunt for longer period companions begins with a search for long-term RV trends within the APOGEE data. We have also obtained diffraction-limited imaging using speckle interferometry at WIYN and Gemini North Observatories, as well as AO LMIRcam images from the LBT, to make direct searches for long-period stellar companions.It is critical to purge our companion candidate detections of false positives, and we discuss several methods we are pursuing to do this. For example, highly active stars have been observed to mimic RV measurements. We have obtained optical high-resolution spectral follow-ups from the ARC 3.5m, the HET, and MMT to analyze potential stellar activity indicators such as Calcium H and K. Emission detected in these well-known stellar activity indicators suggests a false radial velocity measurement.

  15. Label Transfer from APOGEE to LAMOST: Precise Stellar Parameters for 450,000 LAMOST Giants

    Science.gov (United States)

    Ho, Anna Y. Q.; Ness, Melissa K.; Hogg, David W.; Rix, Hans-Walter; Liu, Chao; Yang, Fan; Zhang, Yong; Hou, Yonghui; Wang, Yuefei

    2017-02-01

    In this era of large-scale spectroscopic stellar surveys, measurements of stellar attributes (“labels,” i.e., parameters and abundances) must be made precise and consistent across surveys. Here, we demonstrate that this can be achieved by a data-driven approach to spectral modeling. With The Cannon, we transfer information from the APOGEE survey to determine precise {T}{eff}, {log} {\\text{}}g, [{Fe}/{{H}}], and [α /{{M}}] from the spectra of 450,000 LAMOST giants. The Cannon fits a predictive model for LAMOST spectra using 9952 stars observed in common between the two surveys, taking five labels from APOGEE DR12 as ground truth {T}{eff}, {log} {\\text{}}g, [{Fe}/{{H}}], [α /{{M}}], and K-band extinction {A}{{k}}. The model is then used to infer {T}{eff}, {log} {\\text{}}g, [{Fe}/{{H}}], and [α /{{M}}] for 454,180 giants, 20% of the LAMOST DR2 stellar sample. These are the first [α /{{M}}] values for the full set of LAMOST giants, and the largest catalog of [α /{{M}}] for giant stars to date. Furthermore, these labels are by construction on the APOGEE label scale; for spectra with S/N > 50, cross-validation of the model yields typical uncertainties of 70 K in {T}{eff}, 0.1 in {log} {\\text{}}g, 0.1 in [{Fe}/{{H}}], and 0.04 in [α /{{M}}], values comparable to the broadly stated, conservative APOGEE DR12 uncertainties. Thus, by using “label transfer” to tie low-resolution (LAMOST R ≈ 1800) spectra to the label scale of a much higher-resolution (APOGEE R ≈ 22,500) survey, we substantially reduce the inconsistencies between labels measured by the individual survey pipelines. This demonstrates that label transfer with The Cannon can successfully bring different surveys onto the same physical scale.

  16. Land Mobile Satellite Service (LMSS): A conceptual system design and identification of the critical technologies. Part 1: Executive summary

    Science.gov (United States)

    Naderi, F. (Editor)

    1982-01-01

    A system design for a satellite aided land mobile service is described. The advanced system is based on a geostationary satellite which employs a large UHF reflector to communicate with small user antennas on mobile vehicles. It is shown that the system through multiple beam antennas and frequency reuse provides for radiotelephone and dispatch channels. It is concluded that the system is technologically feasible to provide service to rural and remote regions.

  17. ESA technology flies on Italian mini-satellite launched from Russia

    Science.gov (United States)

    2000-07-01

    Owned by the Italian space agency (ASI) and developed by Carlo Gavazzi with contributions from many other Italian companies, MITA has two tasks to perform: in a circular orbit at 450 km altitude, the mini satellite will carry a cosmic particle detector, while its platform will be tested for the first time as a vehicle for future scientific missions. MITA also carries the MTS-AOMS payload (MicroTechSensor for Attitude and Orbit Measurement System), developed by Astrium in the framework of ESA's Technology Flight Opportunity trial programme. With the Technology Flight Opportunity scheme, funded by its General Studies Programme, ESA intends to provide access to space for European industry's technology products needing in-orbit demonstration to enhance their competitiveness on the space market. This new form of support to the European space industry ties in with ESA's strategy for fostering the competitiveness of European-made technology for eventual commercialisation. In-orbit demonstration is essential if new technologies are to compete on level terms on non-European markets. It thus consolidates strategic investments made by the space industry. The MTS-AOMS is a highly integrated sensor for autonomous attitude and orbit control systems. It combines three functions in one unit: Earth sensing, star sensing and magnetic field sensing. The equipment incorporates an active pixel array sensor and a 2-D fluxgate magnetometer. The aims of the flight are to verify in situ the payload's inherent functions and performance, which cannot be done on the ground, and to assess the behaviour of this type of technology when exposed to the space environment. The Technology Flight Opportunity rule is that ESA funds the launch and integration costs, industry the development and operating costs. According to present planning, two further in-orbit demonstrations funded by this scheme will be carried out between now and January 2001.

  18. Survey and documentation of emerging technologies for the satellite power system (SPS)

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, P.; Chapman, P.

    1981-04-01

    The purpose of this study is to survey emerging technologies and new concepts which may offer advantages over those selected for the SPS Reference System. A brief historical overview of the genesis of the Solar Power Satellite (SPS) concept is presented leading to a discussion of the assumptions and guidelines which were originally established and which led to development of the SPS Reference System design concept. Some of these guidelines are applicable to almost any SPS design, but others could be changed, leading to new and perhaps preferable systems. Moreover, while some of the guidelines are based on solid data, some are little more than arbitrary assumptions which were adopted only to proceed with a concrete point design which then could be assessed in the DOE/NASA Concept Development and Evaluation Program. In order to stimulate new SPS concepts and to facilitate comparative assessment of emerging SPS technologies, one useful approach is to break the overall system into functional parts. The system functions which must be performed by any SPS concept and the interrelations between them are discussed and a systematic framework is presented for assessment of the wide variety of system concepts and subsystem technologies which have been proposed. About 80 alternative SPS technologies are reviewed.

  19. Flight demonstration of new thruster and green propellant technology on the PRISMA satellite

    Science.gov (United States)

    Anflo, K.; Möllerberg, R.

    2009-11-01

    The concept of a storable liquid monopropellant blend for space applications based on ammonium dinitramide (ADN) was invented in 1997, within a co-operation between the Swedish Space Corporation (SSC) and the Swedish Defense Research Agency (FOI). The objective was to develop a propellant which has higher performance and is safer than hydrazine. The work has been performed under contract from the Swedish National Space Board and ESA. The progress of the development has been presented in several papers since 2000. ECAPS, a subsidiary of the Swedish Space Corporation was established in 2000 with the aim to develop and market the novel "high performance green propellant" (HPGP) technology for space applications. The new technology is based on several innovations and patents w.r.t. propellant formulation and thruster design, including a high temperature resistant catalyst and thrust chamber. The first flight demonstration of the HPGP propulsion system will be performed on PRISMA. PRISMA is an international technology demonstration program with Swedish Space Corporation as the Prime Contractor. This paper describes the performance, characteristics, design and verification of the HPGP propulsion system for PRISMA. Compatibility issues related to using a new propellant with COTS components is also discussed. The PRISMA mission includes two satellites in LEO orbit were the focus is on rendezvous and formation flying. One of the satellites will act as a "target" and the main spacecraft performs rendezvous and formation flying maneuvers, where the ECAPS HPGP propulsion system will provide delta-V capability. The PRISMA CDR was held in January 2007. Integration of the flight propulsion system is about to be finalized. The flight opportunity on PRISMA represents a unique opportunity to demonstrate the HPGP propulsion system in space, and thus take a significant step towards its use in future space applications. The launch of PRISMA scheduled to 2009.

  20. Research and Development initiative of Satellite Technology Application for Environmental Issues in Asia Region

    Science.gov (United States)

    Hamamoto, K.; Kaneko, Y.; Sobue, S.; Oyoshi, K.

    2016-12-01

    Climate change and human activities are directly or indirectly influence the acceleration of environmental problems and natural hazards such as forest fires, drought and floods in the Asia-Pacific countries. Satellite technology has become one of the key information sources in assessment, monitoring and mitigation of these hazards and related phenomenon. However, there are still gaps between science and application of space technology in practical usage. Asia-Pacific Regional Space Agency Forum (APRSAF) recommended to initiate the Space Applications for Environment (SAFE) proposal providing opportunity to potential user agencies in the Asia Pacific region to develop prototype applications of space technology for number of key issues including forest resources management, coastal monitoring and management, agriculture and food security, water resource management and development user-friendly tools for application of space technology. The main activity of SAFE is SAFE prototyping. SAFE prototyping is a demonstration for end users and decision makers to apply space technology applications for solving environmental issues in Asia-Pacific region. By utilizing space technology and getting technical support by experts, prototype executers can develop the application system, which could support decision making activities. SAFE holds a workshop once a year. In the workshop, new prototypes are approved and the progress of on-going prototypes are confirmed. Every prototype is limited for two years period and all activities are operated by volunteer manner. As of 2016, 20 prototypes are completed and 6 prototypes are on-going. Some of the completed prototypes, for example drought monitoring in Indonesia were applied to operational use by a local official organization.

  1. Dynamic autonomous routing technology for IP-based satellite ad hoc networks

    Science.gov (United States)

    Wang, Xiaofei; Deng, Jing; Kostas, Theresa; Rajappan, Gowri

    2014-06-01

    IP-based routing for military LEO/MEO satellite ad hoc networks is very challenging due to network and traffic heterogeneity, network topology and traffic dynamics. In this paper, we describe a traffic priority-aware routing scheme for such networks, namely Dynamic Autonomous Routing Technology (DART) for satellite ad hoc networks. DART has a cross-layer design, and conducts routing and resource reservation concurrently for optimal performance in the fluid but predictable satellite ad hoc networks. DART ensures end-to-end data delivery with QoS assurances by only choosing routing paths that have sufficient resources, supporting different packet priority levels. In order to do so, DART incorporates several resource management and innovative routing mechanisms, which dynamically adapt to best fit the prevailing conditions. In particular, DART integrates a resource reservation mechanism to reserve network bandwidth resources; a proactive routing mechanism to set up non-overlapping spanning trees to segregate high priority traffic flows from lower priority flows so that the high priority flows do not face contention from low priority flows; a reactive routing mechanism to arbitrate resources between various traffic priorities when needed; a predictive routing mechanism to set up routes for scheduled missions and for anticipated topology changes for QoS assurance. We present simulation results showing the performance of DART. We have conducted these simulations using the Iridium constellation and trajectories as well as realistic military communications scenarios. The simulation results demonstrate DART's ability to discriminate between high-priority and low-priority traffic flows and ensure disparate QoS requirements of these traffic flows.

  2. An accurate and self-consistent chemical abundance catalogue for the APOGEE/Kepler sample

    Science.gov (United States)

    Hawkins, K.; Masseron, T.; Jofré, P.; Gilmore, G.; Elsworth, Y.; Hekker, S.

    2016-10-01

    Context. The APOGEE survey has obtained high-resolution infrared spectra of more than 100 000 stars. Deriving chemical abundances patterns of these stars is paramount to piecing together the structure of the Milky Way. While the derived chemical abundances have been shown to be precise for most stars, some calibration problems have been reported, in particular for more metal-poor stars. Aims: In this paper, we aim to (1) re-determine the chemical abundances of the APOGEE+Kepler stellar sample (APOKASC) with an independent procedure, line list and line selection, and high-quality surface gravity information from asteroseismology; and (2) extend the abundance catalogue by including abundances that are not currently reported in the most recent APOGEE release (DR12). Methods: We fixed the Teff and log g to those determined using spectrophotometric and asteroseismic techniques, respectively. We made use of the Brussels Automatic Stellar Parameter (BACCHUS) code to derive the metallicity and broadening parameters for the APOKASC sample. In addition, we derived differential abundances with respect to Arcturus. Results: We have validated the BACCHUS code on APOGEE data using several well-known stars, and stars from open and globular clusters. We also provide the abundances of C, N, O, Mg, Ca, Si, Ti, S, Al, Na, Ni, Mn, Fe, K, and V for every star and line, and show the impact of line selection on the final abundances. Improvements have been made for some elements (e.g. Ti, Si, V). Additionally, we measure new abundance ratios not found in the current APOGEE release including P, Cu, Rb, and Yb, which are only upper limits at this time, as well as Co and Cr which are promising. Conclusions: In this paper, we present an independent analysis of the APOKASC sample and provide abundances of up to 21 elements. This catalogue can be used not only to study chemical abundance patterns of the Galaxy but also to train data driven spectral approaches which can improve the abundance

  3. Chemical cartography of the milky way disk with the SDSS-III/Apogee survey

    Science.gov (United States)

    Hayden, Michael R.

    In this thesis I discuss the chemical structure of the Milky Way disk. Much of our knowledge of the Milky Way is restricted to the solar neighborhood due to the significant dust extinction directly in the plane of the Galaxy. SDSS-III/APOGEE is a high-resolution spectroscopic survey of more than 100,000 giant stars operating in the infrared, where extinction is ~ 1/6 compared to visual wavelengths. Individual stars are useful tracers for studying the chemical and kinematic history of the Galaxy, as they contain the chemical imprint of the gas from which they formed. I develop a Bayesian method to determine distances to every star in the APOGEE survey by comparing the observed stellar parameters from APOGEE to theoretical stellar isochrones. Using observations taken during the first year of APOGEE operations, I made mean metallicity maps and characterized radial and vertical chemical abundance gradients across the entire disk of the Galaxy at a range of heights about the plane, from 0 < R < 15 kpc and 0 < ∣z∣ < 3 kpc. Different stellar populations can be separated using [ a/Fe] abundance, and I analyze the stellar distribution in the [ a/Fe] vs. [Fe/H] plane across the disk from 3 < R < 15 kpc and at a range of heights above the plane (∣z∣ < 2 kpc) using the full three years of APOGEE observations. The metallicity distribution function (MDF) is a primary constraint for chemical evolution models, and I measure the MDF across the disk of the Milky Way. I find that the peak metallicity and shape of the MDF is a strong function of location within the Galaxy. Close to the plane, the inner disk is peaked at super-solar metallicities with a long tail towards lower metallicities (negative skewness), while the outer disk is peaked at sub-solar metallicities and a tail towards higher metallicities (positive skewness). The change in skewness with radius is difficult to explain using traditional chemical evolution models, and I made a simple model of the dynamics of the

  4. The precision-processing subsystem for the Earth Resources Technology Satellite.

    Science.gov (United States)

    Chapelle, W. E.; Bybee, J. E.; Bedross, G. M.

    1972-01-01

    Description of the precision processor, a subsystem in the image-processing system for the Earth Resources Technology Satellite (ERTS). This processor is a special-purpose image-measurement and printing system, designed to process user-selected bulk images to produce 1:1,000,000-scale film outputs and digital image data, presented in a Universal-Transverse-Mercator (UTM) projection. The system will remove geometric and radiometric errors introduced by the ERTS multispectral sensors and by the bulk-processor electron-beam recorder. The geometric transformations required for each input scene are determined by resection computations based on reseau measurements and image comparisons with a special ground-control base contained within the system; the images are then printed and digitized by electronic image-transfer techniques.

  5. Design, construction and testing of the Communications Technology Satellite protection against spacecraft charging

    Science.gov (United States)

    Gore, J. V.

    1977-01-01

    Detailed discussions are presented of the measures taken on the Communications Technology Satellite (CTS or Hermes) which provide protection against the effects of spacecraft charging. These measures include: a comprehensive grounding philosophy and implementation; provision of command and data line transmitters and receivers for transient noise immunity; and a fairly restrictive EMI specification. Ground tests were made on materials and the impact of these tests on the CTS spacecraft is described. Hermes, launched on 17 January 1976 on a 2914 Delta vehicle, has successfully completed 10 months of operations. Anomalies observed are being assessed in relation to spacecraft charging, but no definite correlations have yet been established. A list of conclusions with regard to the CTS experience is given and recommendations for future spacecraft are also listed.

  6. Application of the advanced communications technology satellite for teleradiology and telemedicine

    Science.gov (United States)

    Stewart, Brent K.; Carter, Stephen J.; Rowberg, Alan H.

    1995-05-01

    The authors have an in-kind grant from NASA to investigate the application of the Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the JPL developed ACTS Mobile Terminal (AMT) uplink. This experiment involves the transmission of medical imagery (CT, MR, CR, US and digitized radiographs including mammograms), between the ACTS/AMT and the University of Washington. This is accomplished by locating the AMT experiment van in various locations throughout Washington state, Idaho, Montana, Oregon and Hawaii. The medical images are transmitted from the ACTS to the downlink at the NASA Lewis Research Center (LeRC) in Cleveland, Ohio, consisting of AMT equipment and the high burst rate-link evaluation terminal (HBR-LET). These images are then routed from LeRC to the University of Washington School of Medicine (UWSoM) through the Internet and public switched Integrated Serviced Digital Network (ISDN). Once images arrive in the UW Radiology Department, they are reviewed using both video monitor softcopy and laser-printed hardcopy. Compressed video teleconferencing and transmission of real-time ultrasound video between the AMT van and the UWSoM are also tested. Image quality comparisons are made using both subjective diagnostic criteria and quantitative engineering analysis. Evaluation is performed during various weather conditions (including rain to assess rain fade compensation algorithms). Compression techniques also are tested to evaluate their effects on image quality, allowing further evaluation of portable teleradiology/telemedicine at lower data rates and providing useful information for additional applications (e.g., smaller remote units, shipboard, emergency disaster, etc.). The medical images received at the UWSoM over the ACTS are directly evaluated against the original digital images. The project demonstrates that a portable satellite-land connection can provide subspecialty consultation and education for rural and remote

  7. Three Dimensional Stellar Kinematics of the Galactic Bar and Disk: Where APOGEE Meets GLIMPSE

    Science.gov (United States)

    Benjamin, Robert; Babler, Brian; D'Onghia, Elena; Clarkson, Will; Churchwell, Ed; Kirkpatrick, Davy; Zasowski, Gail; Majewski, Steve

    2016-08-01

    We propose to use the Spitzer Space Telescope to re-image 53 square degrees (fourteen fields) of the inner Galactic plane (galactic longitudes \\|L\\|=6-45 degrees) that have also been targeted by the APOGEE/APOGEE-2 surveys-Sloan III and IV programs to obtain high resolution H band spectroscopy for hundreds of thousands of red giants. We will combine the proposed observations (198 hours) with the original GLIMPSE observations of the Galactic plane in 2004-2005 to measure the proper motions of sources along the Galactic plane over the past decade. When combined with the 43 square degrees of Priority 1 data being obtained for Cycle 12--which cover \\|L\\|crowded Galactic disk.

  8. A catalog of 1.5273 micron diffuse interstellar bands based on APOGEE hot telluric calibrators

    CERN Document Server

    Elyajouri, Meriem; Remy, Quentin; Lallement, Rosine

    2016-01-01

    High resolution stellar spectroscopic surveys provide massive amounts of diffuse interstellar bands (DIBs) measurements. Data can be used to study the distribution of the DIB carriers and those environmental conditions that favor their formation. In parallel, recent studies have also proved that DIBs extracted from stellar spectra constitute new tools for building the 3D structure of the Galactic Interstellar Medium (ISM). The amount of details on the structure depends directly on the quantity of available lines of sight (LOS). Therefore there is a need to construct databases of high-quality DIB measurements as large as possible. We aim at providing the community with a catalog of high-quality measurements of the 1.5273 micron DIB towards a large fraction of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) hot stars observed to correct for the telluric absorption and not used for ISM studies so far. This catalog would complement the extensive database recently extracted from the APOGEE obse...

  9. Bayesian distances and extinctions for giants observed by Kepler and APOGEE

    CERN Document Server

    Rodrigues, Thaíse S; Miglio, Andrea; Bossini, Diego; Bovy, Jo; Epstein, Courtney; Pinsonneault, Marc H; Stello, Dennis; Zasowski, Gail; Prieto, Carlos Allende; Chaplin, William J; Hekker, Saskia; Johnson, Jennifer A; Mészáros, Szabolcs; Mosser, Benoît; Anders, Friedrich; Basu, Sarbani; Beers, Timothy C; Chiappini, Cristina; da Costa, Luiz A N; Elsworth, Yvonne; García, Rafael A; Pérez, Ana E García; Hearty, Fred R; Maia, Marcio A G; Majewski, Steven R; Mathur, Savita; Montalbán, Josefina; Nidever, David L; Santiago, Basilio; Schultheis, Mathias; Serenelli, Aldo; Shetrone, Matthew

    2014-01-01

    We present a first determination of distances and extinctions for individual stars in the first release of the APOKASC catalogue, built from the joint efforts of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) and the Kepler Asteroseismic Science Consortium (KASC). Our method takes into account the spectroscopic constraints derived from the APOGEE Stellar Parameters and Chemical Abundances Pipeline, together with the asteroseismic parameters from KASC. These parameters are then employed to estimate intrinsic stellar properties, including absolute magnitudes, using the Bayesian tool PARAM. We then find the distance and extinction that best fit the observed photometry in SDSS, 2MASS, and WISE passbands. The first 1989 giants targeted by APOKASC are found at typical distances between 0.5 and 5 kpc, with individual uncertainties of just ~1.8 per cent. Our extinction estimates are systematically smaller than provided in the Kepler Input Catalogue and by the Schlegel, Finkbeiner and Davis maps. ...

  10. Survey Cross-Calibration with The Cannon: APOGEE-scale Stellar Labels from LAMOST Spectra

    CERN Document Server

    Ho, Anna Y Q; Hogg, David W; Rix, Hans-Walter; Liu, Chao; Yang, Fan; Zhang, Yong; Hou, Yonghui; Wang, Yuefei

    2016-01-01

    To capitalize on a diverse set of large spectroscopic stellar surveys, it is essential to develop techniques for precise and accurate survey cross-calibration. Here, we demonstrate that this can be achieved by a data-driven approach to spectral modeling: we use The Cannon (Ness et al. 2015) to cross-calibrate APOGEE and LAMOST, two large-scale surveys that currently yield inconsistent results due to differing experimental setups and data analysis methodologies. The Cannon constructs a predictive model for LAMOST spectra using a reference set of 9952 stars observed in common between the two surveys, taking five labels as ground truth from APOGEE DR12: Teff, log g, [Fe/H], [\\alpha/M], and K-band extinction A_k. The model is then used to infer Teff, log g, [Fe/H], and [\\alpha/M] for 454,180 giant stars in LAMOST DR2, thus tying low-resolution (R=1800) LAMOST spectra to the APOGEE (R=22,500) label scale. Despite being derived directly from LAMOST spectra, which have lower spectral resolution and very different wa...

  11. Age-Metallicity Relationships Across the Milky Way Galaxy with APOGEE

    Science.gov (United States)

    Casados-Medve, Colton; Bird, Jonathan C.; APOGEE Team (Sloan Digital Sky Survey)

    2017-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has measured the infrared spectrum of over 160,000 stars. The unique combination of high resolution (R~20,000) and infrared wavelength coverage allows APOGEE to determine precise abundances for ~15 elements in stars located across the Galactic midplane, from ~3 kpc to ~15 kpc. The observed metallicity gradient over this radial range is also accompanied by a change in the shape of the metallicity distribution function (MDF) as a function of galactocentric radius (Hayden et al. 2015). Here, we combine the APOGEE sample with stellar age determinations (Ness et al. 2016) to measure how the distribution of stellar metals changes as a function of both galactocentric radius and age. We determine the age-metallicity relationship (AMR) in several radial zones, allowing comparison with the AMR measured in the local solar neighborhood. In addition, our analysis shows the skewness of the MDF changes as a function of radius even for the youngest (age stars. These stars are too young to have migrated far from their birth radii. Our results suggest that the changing skew of the MDF with radius does not require substantial radial migration in the disk as recent studies contend.

  12. Educational Applications of Communications Satellites in Canada. New Technologies in Canadian Education Series. Paper 12.

    Science.gov (United States)

    Richmond, J. Murray

    Canada has explored the use of satellites as a means to provide information and communications services to geographically isolated populations since 1962. Between 1972 and 1984, five series of satellites known as Anik A, B, C, and D and Hermes were launched. Each satellite provided expanded communications services, and each led to research and…

  13. Launch Vehicles Based on Advanced Hybrid Rocket Motors: An Enabling Technology for the Commercial Small and Micro Satellite Planetary Science

    Science.gov (United States)

    Karabeyoglu, Arif; Tuncer, Onur; Inalhan, Gokhan

    2016-07-01

    Mankind is relient on chemical propulsion systems for space access. Nevertheless, this has been a stagnant area in terms of technological development and the technology base has not changed much almost for the past forty years. This poses a vicious circle for launch applications such that high launch costs constrain the demand and low launch freqencies drive costs higher. This also has been a key limiting factor for small and micro satellites that are geared towards planetary science. Rather this be because of the launch frequencies or the costs, the access of small and micro satellites to orbit has been limited. With today's technology it is not possible to escape this circle. However the emergence of cost effective and high performance propulsion systems such as advanced hybrid rockets can decrease launch costs by almost an order or magnitude. This paper briefly introduces the timeline and research challenges that were overcome during the development of advanced hybrid LOX/paraffin based rockets. Experimental studies demonstrated effectiveness of these advanced hybrid rockets which incorporate fast burning parafin based fuels, advanced yet simple internal balistic design and carbon composite winding/fuel casting technology that enables the rocket motor to be built from inside out. A feasibility scenario is studied using these rocket motors as building blocks for a modular launch vehicle capable of delivering micro satellites into low earth orbit. In addition, the building block rocket motor can be used further solar system missions providing the ability to do standalone small and micro satellite missions to planets within the solar system. This enabling technology therefore offers a viable alternative in order to escape the viscous that has plagued the space launch industry and that has limited the small and micro satellite delivery for planetary science.

  14. Design and Development of the WVU Advanced Technology Satellite for Optical Navigation

    Science.gov (United States)

    Straub, Miranda

    In order to meet the demands of future space missions, it is beneficial for spacecraft to have the capability to support autonomous navigation. This is true for both crewed and uncrewed vehicles. For crewed vehicles, autonomous navigation would allow the crew to safely navigate home in the event of a communication system failure. For uncrewed missions, autonomous navigation reduces the demand on ground-based infrastructure and could allow for more flexible operation. One promising technique for achieving these goals is through optical navigation. To this end, the present work considers how camera images of the Earth's surface could enable autonomous navigation of a satellite in low Earth orbit. Specifically, this study will investigate the use of coastlines and other natural land-water boundaries for navigation. Observed coastlines can be matched to a pre-existing coastline database in order to determine the location of the spacecraft. This paper examines how such measurements may be processed in an on-board extended Kalman filter (EKF) to provide completely autonomous estimates of the spacecraft state throughout the duration of the mission. In addition, future work includes implementing this work on a CubeSat mission within the WVU Applied Space Exploration Lab (ASEL). The mission titled WVU Advanced Technology Satellite for Optical Navigation (WATSON) will provide students with an opportunity to experience the life cycle of a spacecraft from design through operation while hopefully meeting the primary and secondary goals defined for mission success. The spacecraft design process, although simplified by CubeSat standards, will be discussed in this thesis as well as the current results of laboratory testing with the CubeSat model in the ASEL.

  15. Observations of a Unique Type of ULF Waves by Low-Latitude Space Technology 5 Satellites

    Science.gov (United States)

    Le, G.; Chi, P. J.; Strangeway, R. J.; Slavin, J. A.

    2011-01-01

    We report a unique type of ULF waves observed by low-altitude Space Technology 5 (ST-5) constellation mission. ST-5 is a three micro-satellite constellation deployed into a 300 x 4500 km, dawn-dusk, and sun synchronous polar orbit with 105.6deg inclination angle. Due to the Earth s rotation and the dipole tilt effect, the spacecraft s dawn-dusk orbit track can reach as low as subauroral latitudes during the course of a day. Whenever the spacecraft traverse across the dayside closed field line region at subauroral latitudes, they frequently observe strong transverse oscillations at 30-200 mHz, or in the Pc 2-3 frequency range. These Pc 2-3 waves appear as wave packets with durations in the order of 5-10 minutes. As the maximum separations of the ST-5 spacecraft are in the order of 10 minutes, the three ST-5 satellites often observe very similar wave packets, implying these wave oscillations occur in a localized region. The coordinated ground-based magnetic observations at the spacecraft footprints, however, do not see waves in the Pc 2-3 band; instead, the waves appear to be the common Pc 4-5 waves associated with field line resonances. We suggest that this unique Pc 2-3 waves seen by ST-5 are in fact the Doppler-shifted Pc 4-5 waves as a result of rapid traverse of the spacecraft across the resonant field lines azimuthally at low altitudes. The observations with the unique spacecraft dawn-disk orbits at proper altitudes and magnetic latitudes reveal the azimuthal characteristics of field-aligned resonances.

  16. Apogee, Perigee, and Recovery: Chronology of Army Exploitation of Space

    Science.gov (United States)

    1989-01-01

    Huntsville, Alabama ........................... 43 14. The high-acceleration Sprint missile blasts out of its White Sands Missile Range launch cell ...Defense BMDATC Ballistic Missile Defense Advanced Technology Center - xxii - BMDC Ballistic Missile Defense Center BMDO Ballistic Missile Defense...9- - 44 - PlBe 14-The high-acceleration Sprint missile blasts out of its White Sands Missile Range launch cell during flight testing. 45 E cc. - 46

  17. Characterization of the CTS 12 and 14 GHz communications links - Preliminary measurements and evaluation. [Communications Technology Satellite

    Science.gov (United States)

    Ippolito, L. J.

    1976-01-01

    The Communications Link Characterization Experiment is designed to characterize the radio frequency links of the Communications Technology Satellite. The experiment is twofold: (1) it will study the natural characteristics in the CTS frequency bands (14 GHz uplink, and 12 GHz downlink) including attenuation and signal degradation due primarily to absorption and scattering induced by precipitation, and (2) it will perform environmental measurements for the characterization of man-made, earth-based signals which could interfere with the uplink frequency bands of the satellite.

  18. Forecast analysis on satellites that need de-orbit technologies: future scenarios for passive de-orbit devices

    Science.gov (United States)

    Palla, Chiara; Kingston, Jennifer

    2016-09-01

    Propulsion-based de-orbit is a space-proven technology; however, this strategy can strongly limit operational lifetime, as fuel mass is dedicated to the de-orbiting. In addition previous reliability studies have identified the propulsion subsystem as one of the major contributors driving satellite failures. This issue brings the need to develop affordable de-orbit technologies with a limited reliance on the system level performance of the host satellite, ideally largely passive methods. Passive disposal strategies which take advantage of aerodynamic drag as the de-orbit force are particularly attractive because they are independent of spacecraft propulsion capabilities. This paper investigates the future market for passive de-orbit devices in LEO to aid in defining top-level requirements for the design of such devices. This is performed by considering the compliances of projected future satellites with the Inter Agency Space Debris Coordination Committee de-orbit time, to quantify the number of spacecraft that are compliant or non-compliant with the guidelines and, in this way, determine their need for the previously discussed devices. The study is performed by using the SpaceTrak™ database which provides future launch schedules, and spacecraft information; the de-orbit analysis is carried out by means of simulations with STELA. A case study of a passive strategy is given by the de-orbit mechanism technological demonstrator, which is currently under development at Cranfield University and designed to deploy a drag sail at the end of the ESEO satellite mission.

  19. Spatial Mapping of NEO 2008 EV5 Using Small Satellite Formation Flying and Steresoscopic Technology

    Science.gov (United States)

    Gonzalez, Juan; Singh Derewa, Chrishma

    2016-10-01

    NASA is currently developing the first-ever robotic Asteroid Redirect Robotic Mission (ARRM) to the near-Earth asteroid 2008 EV5 with the objective to capture a multi-ton boulder from the asteroids surface and use its mass to redirect its parent into a CIS lunar orbit where astronauts will study its physical and chemical composition.A critical step towards achieving this mission is to effectively map the target asteroid, identify the candidate boulder for retrieval and characterize its critical parameters. Currently, ARRM utilizes a laser altimeter to characterize the height of the boulders and mapping for final autonomous control of the capture. The proposed Lava-Kusha mission provides the increased of stereoscopic imaging and mapping, not only the Earthward side of the asteroid which has been observed for possible landing sites, but mapping the whole asteroid. LKM will enhance the fidelity of the data collected by the laser altimeter and gather improved topographic data for future Orion missions to 2008 EV5 once in cis lunar space.LKM consists of two low cost small satellites (6U) as a part of the ARRM. They will launch with ARRM as an integrated part of the system. Once at the target, this formation of pathfinder satellites will image the mission critical boulder to ensure the system design can support its removal. LKM will conduct a series of flybys prior to ARRM's rendezvous. LKMs stereoscopic cameras will provide detailed surveys of the boulder's terrain and environment to ensure ARRM can operate safely, reach the location and interface with the boulder. The LKM attitude control and cold gas propulsion system will enable formation maintenance maneuvers for global mapping of asteroid 2008 EV5 at an altitude of 100 km to a high-spatial resolution imaging altitude of 5 km.LKM will demonstrate formation flying in deep space and the reliability of stereoscopic cameras to precisely identify a specific target and provide physical characterization of an asteroid. An

  20. The Apache Point Observatory Galactic Evolution Experiment (APOGEE) high-resolution near-infrared multi-object fiber spectrograph

    Science.gov (United States)

    Wilson, John C.; Hearty, Fred; Skrutskie, Michael F.; Majewski, Steven; Schiavon, Ricardo; Eisenstein, Daniel; Gunn, Jim; Blank, Basil; Henderson, Chuck; Smee, Stephen; Barkhouser, Robert; Harding, Al; Fitzgerald, Greg; Stolberg, Todd; Arns, Jim; Nelson, Matt; Brunner, Sophia; Burton, Adam; Walker, Eric; Lam, Charles; Maseman, Paul; Barr, Jim; Leger, French; Carey, Larry; MacDonald, Nick; Horne, Todd; Young, Erick; Rieke, George; Rieke, Marcia; O'Brien, Tom; Hope, Steve; Krakula, John; Crane, Jeff; Zhao, Bo; Carr, Mike; Harrison, Craig; Stoll, Robert; Vernieri, Mary A.; Holtzman, Jon; Shetrone, Matt; Allende-Prieto, Carlos; Johnson, Jennifer; Frinchaboy, Peter; Zasowski, Gail; Bizyaev, Dmitry; Gillespie, Bruce; Weinberg, David

    2010-07-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) will use a dedicated 300-fiber, narrow-band (1.5-1.7 micron), high resolution (R~30,000), near-infrared spectrograph to survey approximately 100,000 giant stars across the Milky Way. This survey, conducted as part of the Sloan Digital Sky Survey III (SDSS III), will revolutionize our understanding of kinematical and chemical enrichment histories of all Galactic stellar populations. The instrument, currently in fabrication, will be housed in a separate building adjacent to the 2.5 m SDSS telescope and fed light via approximately 45-meter fiber runs from the telescope. The instrument design includes numerous technological challenges and innovations including a gang connector that allows simultaneous connection of all fibers with a single plug to a telescope cartridge that positions the fibers on the sky, numerous places in the fiber train in which focal ratio degradation must be minimized, a large (290 mm x 475 mm elliptically-shaped recorded area) mosaic-VPH, an f/1.4 sixelement refractive camera featuring silicon and fused silica elements with diameters as large as 393 mm, three near-within a custom, LN2-cooled, stainless steel vacuum cryostat with dimensions 1.4 m x 2.3 m x 1.3 m.

  1. Satellite-based technology, systems testing of fishing vessels: Newfoundland Region (1997) = Essais de systèmes de satellites pour les bateaux de pêche : règion de Terre-Neuve (1997)

    National Research Council Canada - National Science Library

    1998-01-01

    The application of satellite-based technology for monitoring fishing vessels and fishing activity is an effective management tool, permitting two-way communication and electronic tracking and reporting...

  2. Low Profile and Low Cost Antenna Technology for Satellite TV Reception on Sports Utility Vehicles (SUV) for the US Market

    Science.gov (United States)

    Vazquez, F. Javier; Pearson, Robert A.; Driscoll, Barry G.

    2003-07-01

    A low profile scanning antenna for reception of satellite TV has been developed for the US market compatible with existing DBS Ku band satellite infrastructure. This antenna technology does not require active RF components and it is inherently low cost (in the order of a few hundred dollars even in moderate production volumes). The antenna is able to scan a circularly polarised beam in the range 20 to 69 degrees, covering three DBS satellites in the US including some margin for vehicle tilt. An antenna demonstrator of 115 mm height, including the radome and tracking electronics has been built and measured. Live tests were performed in the US during 2002 to determine realistic link margins and antenna specifications. A product development is currently being undertaken to turn the demonstrator unit into a product for the US market by the end of 2003.

  3. Advanced Communications Technology Satellite (ACTS) Fade Compensation Protocol Impact on Very Small-Aperture Terminal Bit Error Rate Performance

    Science.gov (United States)

    Cox, Christina B.; Coney, Thom A.

    1999-01-01

    The Advanced Communications Technology Satellite (ACTS) communications system operates at Ka band. ACTS uses an adaptive rain fade compensation protocol to reduce the impact of signal attenuation resulting from propagation effects. The purpose of this paper is to present the results of an analysis characterizing the improvement in VSAT performance provided by this protocol. The metric for performance is VSAT bit error rate (BER) availability. The acceptable availability defined by communication system design specifications is 99.5% for a BER of 5E-7 or better. VSAT BER availabilities with and without rain fade compensation are presented. A comparison shows the improvement in BER availability realized with rain fade compensation. Results are presented for an eight-month period and for 24 months spread over a three-year period. The two time periods represent two different configurations of the fade compensation protocol. Index Terms-Adaptive coding, attenuation, propagation, rain, satellite communication, satellites.

  4. Life characteristics assessment of the communications technology satellite transmitter experiment package

    Science.gov (United States)

    Smetana, J.; Curren, A. N.

    1979-01-01

    The performance characteristics of the transmitter experiment package (TEP) aboard the Communications Technology Satellite (CTS) measured during its first 2 years in orbit are presented. The TEP consists of a nominal 200 watt output stage tube (OST), a supporting power processing system (PPS), and a variable conductance heat pipe system (VCHPS). The OST, a traveling wave tube augmented with a 10 stage depressed collector has an overall saturated average efficiency of 51.5 percent and an average saturated radio frequency (rf) output power at center band frequency of 240 watts. The PPS operated with a measured efficiency of 86.5 to 88.5 percent. The VCHPS, using three pipes to conduct heat from the PPS and the OST to a 52 by 124 centimeter radiator fin, maintained the PPS baseplate temperature below 50 C for all operating conditions. The TEP performance characteristics presented include frequency response, rf output power, thermal performance, and efficiency. Communications characteristics were evaluated by using both video and audio modulated signals. On four occasions, the TEP experienced temporary thermal control system malfunctions. The anomalies were terminated safely, and the problem was investigated because of the potential for TEP damage due to the signficant temperature increases. Safe TEP operating procedures were established.

  5. Dynamic rain fade compensation techniques for the advanced communications technology satellite

    Science.gov (United States)

    Manning, Robert M.

    1992-01-01

    The dynamic and composite nature of propagation impairments that are incurred on earth-space communications links at frequencies in and above the 30/20 GHz Ka band necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) project by the implementation of optimal processing schemes derived through the use of the ACTS Rain Attenuation Prediction Model and nonlinear Markov filtering theory. The ACTS Rain Attenuation Prediction Model discerns climatological variations on the order of 0.5 deg in latitude and longitude in the continental U.S. The time-dependent portion of the model gives precise availability predictions for the 'spot beam' links of ACTS. However, the structure of the dynamic portion of the model, which yields performance parameters such as fade duration probabilities, is isomorphic to the state-variable approach of stochastic control theory and is amenable to the design of such statistical fade processing schemes which can be made specific to the particular climatological location at which they are employed.

  6. Advanced Communication Technology Satellite (ACTS) Multibeam Antenna On-Orbit Performance

    Science.gov (United States)

    1995-01-01

    The NASA Lewis Research Center's Advanced Communication Technology Satellite (ACTS) was launched in September 1993. ACTS introduced several new technologies, including a multibeam antenna (MBA) operating at extremely short wavelengths never before used in communications. This antenna, which has both fixed and rapidly reconfigurable high-energy spot beams (150 miles in diameter), serves users equipped with small antenna terminals. Extensive structural and thermal analyses have been performed for simulating the ACTS MBA on-orbit performance. The results show that the reflector surfaces (mainly the front subreflector), antenna support assembly, and metallic surfaces on the spacecraft body will be distorted because of the thermal effects of varying solar heating, which degrade the ACTS MBA performance. Since ACTS was launched, a number of evaluations have been performed to assess MBA performance in the space environment. For example, the on-orbit performance measurements found systematic environmental disturbances to the MBA beam pointing. These disturbances were found to be imposed by the attitude control system, antenna and spacecraft mechanical alignments, and on-orbit thermal effects. As a result, the MBA may not always exactly cover the intended service area. In addition, the on-orbit measurements showed that antenna pointing accuracy is the performance parameter most sensitive to thermal distortions on the front subreflector surface and antenna support assemblies. Several compensation approaches were tested and evaluated to restore on-orbit pointing stability. A combination of autotrack (75 percent of the time) and Earth sensor control (25 percent of the time) was found to be the best way to compensate for antenna pointing error during orbit. This approach greatly minimizes the effects of thermal distortions on antenna beam pointing.

  7. Integration of environmental simulation models with satellite remote sensing and geographic information systems technologies: case studies

    Science.gov (United States)

    Steyaert, Louis T.; Loveland, Thomas R.; Brown, Jesslyn F.; Reed, Bradley C.

    1993-01-01

    Environmental modelers are testing and evaluating a prototype land cover characteristics database for the conterminous United States developed by the EROS Data Center of the U.S. Geological Survey and the University of Nebraska Center for Advanced Land Management Information Technologies. This database was developed from multi temporal, 1-kilometer advanced very high resolution radiometer (AVHRR) data for 1990 and various ancillary data sets such as elevation, ecological regions, and selected climatic normals. Several case studies using this database were analyzed to illustrate the integration of satellite remote sensing and geographic information systems technologies with land-atmosphere interactions models at a variety of spatial and temporal scales. The case studies are representative of contemporary environmental simulation modeling at local to regional levels in global change research, land and water resource management, and environmental simulation modeling at local to regional levels in global change research, land and water resource management and environmental risk assessment. The case studies feature land surface parameterizations for atmospheric mesoscale and global climate models; biogenic-hydrocarbons emissions models; distributed parameter watershed and other hydrological models; and various ecological models such as ecosystem, dynamics, biogeochemical cycles, ecotone variability, and equilibrium vegetation models. The case studies demonstrate the important of multi temporal AVHRR data to develop to develop and maintain a flexible, near-realtime land cover characteristics database. Moreover, such a flexible database is needed to derive various vegetation classification schemes, to aggregate data for nested models, to develop remote sensing algorithms, and to provide data on dynamic landscape characteristics. The case studies illustrate how such a database supports research on spatial heterogeneity, land use, sensitivity analysis, and scaling issues

  8. On-orbit control of the Communications Technology Satellite (CTS)/HERMES

    Science.gov (United States)

    Raine, H. R.

    1980-01-01

    A variety of control functions for the CIS HERMES satellite are reviewed. Its mission, to demonstrate high power SHF (12 GHz) transmission is discussed. The satellite was controlled in geostationary orbit for nearly four years from the satellite control center in Ottawa, Canada. Highlights of these operations are outlined. The interactions between many of the automatic onboard control functions and control from the ground are described. Special emphasis is placed on the characteristics and performance of the three axis attitude control system.

  9. Preliminary comparative assessment of land use for the Satellite Power System (SPS) and alternative electric energy technologies

    Science.gov (United States)

    Newsom, D. E.; Wolsko, T.

    1980-01-01

    A preliminary comparative assessment of land use for the satellite power system (SPS), other solar technologies, and alternative electric energy technologies was conducted. The alternative technologies are coal gasification/combined-cycle, coal fluidized-bed combustion (FBC), light water reactor (LWR), liquid metal fast breeder reactor (LMFBR), terrestrial photovoltaics (TPV), solar thermal electric (STE), and ocean thermal energy conversion (OTEC). The major issues of a land use assessment are the quantity, purpose, duration, location, and costs of the required land use. The phased methodology described treats the first four issues, but not the costs. Several past efforts are comparative or single technology assessment are reviewed briefly. The current state of knowledge about land use is described for each technology. Conclusions are drawn regarding deficiencies in the data on comparative land use and needs for further research.

  10. CALIBRATIONS OF ATMOSPHERIC PARAMETERS OBTAINED FROM THE FIRST YEAR OF SDSS-III APOGEE OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Mészáros, Sz.; Allende Prieto, C. [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Holtzman, J. [New Mexico State University, Las Cruces, NM 88003 (United States); García Pérez, A. E.; Chojnowski, S. D.; Hearty, F. R.; Majewski, S. R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Schiavon, R. P. [Astrophysics Research Institute, Liverpool John Moores University, Egerton Wharf, Birkenhead, Wirral CH41 1LD (United Kingdom); Basu, S. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Bizyaev, D. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Chaplin, W. J.; Elsworth, Y. [University of Birmingham, School of Physics and Astronomy, Edgbaston, Birmingham B15 2TT (United Kingdom); Cunha, K. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Epstein, C.; Johnson, J. A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Frinchaboy, P. M. [Texas Christian University, Fort Worth, TX 76129 (United States); García, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Université Paris Diderot, IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Hekker, S. [Astronomical Institute ' ' Anton Pannekoek' ' , University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Kallinger, T. [Institute for Astronomy, University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Koesterke, L. [Texas Advanced Computing Center, University of Texas, Austin, TX 78759 (United States); and others

    2013-11-01

    The Sloan Digital Sky Survey III (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a three-year survey that is collecting 10{sup 5} high-resolution spectra in the near-IR across multiple Galactic populations. To derive stellar parameters and chemical compositions from this massive data set, the APOGEE Stellar Parameters and Chemical Abundances Pipeline (ASPCAP) has been developed. Here, we describe empirical calibrations of stellar parameters presented in the first SDSS-III APOGEE data release (DR10). These calibrations were enabled by observations of 559 stars in 20 globular and open clusters. The cluster observations were supplemented by observations of stars in NASA's Kepler field that have well determined surface gravities from asteroseismic analysis. We discuss the accuracy and precision of the derived stellar parameters, considering especially effective temperature, surface gravity, and metallicity; we also briefly discuss the derived results for the abundances of the α-elements, carbon, and nitrogen. Overall, we find that ASPCAP achieves reasonably accurate results for temperature and metallicity, but suffers from systematic errors in surface gravity. We derive calibration relations that bring the raw ASPCAP results into better agreement with independently determined stellar parameters. The internal scatter of ASPCAP parameters within clusters suggests that metallicities are measured with a precision better than 0.1 dex, effective temperatures better than 150 K, and surface gravities better than 0.2 dex. The understanding provided by the clusters and Kepler giants on the current accuracy and precision will be invaluable for future improvements of the pipeline.

  11. Galactic Archaeology with CoRoT and APOGEE: Creating mock observations from a chemodynamical model

    Science.gov (United States)

    Anders, F.; Chiappini, C.; Rodrigues, T. S.; Piffl, T.; Mosser, B.; Miglio, A.; Montalbán, J.; Girardi, L.; Minchev, I.; Valentini, M.; Steinmetz, M.

    2016-09-01

    In a companion paper, we have presented the combined asteroseismic-spectroscopic dataset obtained from CoRoT light curves and APOGEE infra-red spectra for 606 solar-like oscillating red giants in two fields of the Galactic disc (CoRoGEE). We have measured chemical abundance patterns, distances, and ages of these field stars which are spread over a large radial range of the Milky Way's disc. Here we show how to simulate this dataset using a chemodynamical Galaxy model. We also demonstrate how the observation procedure influences the accuracy of our estimated ages.

  12. Galactic Archaeology with CoRoT and APOGEE: Creating mock observations from a chemodynamical model

    CERN Document Server

    Anders, F; Rodrigues, T S; Piffl, T; Mosser, B; Miglio, A; Montalbán, J; Girardi, L; Minchev, I; Valentini, M; Steinmetz, M

    2016-01-01

    In a companion paper, we have presented the combined asteroseismic-spectroscopic dataset obtained from CoRoT lightcurves and APOGEE infra-red spectra for 678 solar-like oscillating red giants in two fields of the Galactic disc (CoRoGEE). We have measured chemical abundance patterns, distances, and ages of these field stars which are spread over a large radial range of the Milky Way's disc. Here we show how to simulate this dataset using a chemodynamical Galaxy model. We also demonstrate how the observation procedure influences the accuracy of our estimated ages.

  13. Observations of a Unique Type of ULF Wave by Low-Altitude Space Technology 5 Satellites

    Science.gov (United States)

    Le, G.; Chi, P. J.; Strangeway, R. J.; Slavin, J. A.

    2011-01-01

    We report a unique type of ULF waves observed by low-altitude Space Technology 5 (ST-5) constellation mission. ST-5 is a three-microsatellite constellation deployed into a 300 x 4500 km dawn-dusk and Sun-synchronous polar orbit with 105.6deg inclination angle. Because of the Earth's rotation and the dipole tilt effect, the spacecraft's dawn-dusk orbit track can reach as low as subauroral latitudes during the course of a day. Whenever the spacecraft traverse the dayside closed field line region at subauroral latitudes, they frequently observe strong transverse oscillations at 30-200 mHz, or in the Pc2-3 frequency range. These Pc2-3 waves appear as wave packets with durations in the order of 5-10 min. As the maximum separations of the ST-5 spacecraft are in the order of 10 min, the three ST-5 satellites often observe very similar wave packets, implying these wave oscillations occur in a localized region. The coordinated ground-based magnetic observations at the spacecraft footprints, however, do not see waves in the Pc2-3 band; instead, the waves appear to be the common Pc4-5 waves associated with field line resonances. We suggest that these unique Pc2-3 waves seen by ST-5 are in fact the Doppler-shifted Pc4-5 waves as a result of rapid traverse of the spacecraft across the resonant field lines azimuthally at low altitudes. The observations with the unique spacecraft dawn-dusk orbits at proper altitudes and magnetic latitudes reveal the azimuthal characteristics of field line resonances.

  14. Application of communications satellites to educational development. [technology utilization/information systems - bibliographies

    Science.gov (United States)

    Morgan, R. P.

    1975-01-01

    A summary of research is presented. The broad objectives of this interdisciplinary research effort were: (1) to assess the role of satellite communications as a means of improving education in the United States, as well as in less-developed areas of the world; (2) to generate basic knowledge which will aid in making rational decisions about satellite application in the field of education in the years ahead; (3) to devise systems and strategies for improving education; and (4) to educate individuals who will be knowledgeable about aspects of satellite communications policy which transcend any single discipline.

  15. A Covert Disruptive Technology: Test and Development of the Corona Satellite

    Science.gov (United States)

    Peebles, Curtis

    2008-01-01

    The launching by the Soviet Union of the Sputnik satellite in 19457 was an impetuous to the United States. The Intercontinental ballistic Missile (ICBM) that launched the Earth's first satellite, could have been armed with a nuclear warhead, that could destroy an American city. The primary intelligence requirement that the US had was to determine the actual size of the Soviet missile program. To this end, a covert, high-risk photoreconnaissance satellite was developed. The code name of this program was "Corona." This article describes the trials and eventual successes of the Corona program.

  16. A Covert Disruptive Technology: Test and Development of the Corona Satellite

    Science.gov (United States)

    Peebles, Curtis

    2008-01-01

    The launching by the Soviet Union of the Sputnik satellite in 19457 was an impetuous to the United States. The Intercontinental ballistic Missile (ICBM) that launched the Earth's first satellite, could have been armed with a nuclear warhead, that could destroy an American city. The primary intelligence requirement that the US had was to determine the actual size of the Soviet missile program. To this end, a covert, high-risk photoreconnaissance satellite was developed. The code name of this program was "Corona." This article describes the trials and eventual successes of the Corona program.

  17. Life Science Research in Outer Space: New Platform Technologies for Low-Cost, Autonomous Small Satellite Missions

    Science.gov (United States)

    Ricco, Antonio J.; Parra, Macarena P.; Niesel, David; McGinnis, Michael; Ehrenfreund, Pascale; Nicholson, Wayne; Mancinelli, Rocco; Piccini, Matthew E.; Beasley, Christopher C.; Timucin, Linda R.; Ricks, Robert D.; McIntyre, Michael J.; Squires, David; Yost, Bruce D.; Hines, John W.

    2009-01-01

    We develop integrated instruments and platforms suitable for economical, frequent space access for autonomous life science experiments and processes in outer space. The technologies represented by three of our recent free-flyer small-satellite missions are the basis of a rapidly growing toolbox of miniaturized biologically/biochemically-oriented instrumentation now enabling a new generation of in-situ space experiments. Autonomous small satellites ( 1 50 kg) are less expensive to develop and build than fullsize spacecraft and not subject to the comparatively high costs and scheduling challenges of human-tended experimentation on the International Space Station, Space Shuttle, and comparable platforms. A growing number of commercial, government, military, and civilian space launches now carry small secondary science payloads at far lower cost than dedicated missions; the number of opportunities is particularly large for so-called cube-sat and multicube satellites in the 1 10 kg range. The recent explosion in nano-, micro-, and miniature technologies, spanning fields from telecommunications to materials to bio/chemical analysis, enables development of remarkably capable autonomous miniaturized instruments to accomplish remote biological experimentation. High-throughput drug discovery, point-of-care medical diagnostics, and genetic analysis are applications driving rapid progress in autonomous bioanalytical technology. Three of our recent missions exemplify the development of miniaturized analytical payload instrumentation: GeneSat-1 (launched: December 2006), PharmaSat (launched: May 2009), and O/OREOS (organism/organics exposure to orbital stresses; scheduled launch: May 2010). We will highlight the overall architecture and integration of fluidic, optical, sensor, thermal, and electronic technologies and subsystems to support and monitor the growth of microorganisms in culture in these small autonomous space satellites, including real-time tracking of their culture

  18. Regeneratively-Cooled, Pump-Fed Propulsion Technology for Nano / Micro Satellite Launch Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Ventions proposes the development of a pump-fed, 2-stage nano launch vehicle for low-cost on demand placement of cube and nano-satellites into LEO. The proposed...

  19. New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE survey

    CERN Document Server

    Zamora, O; Prieto, C Allende; Carrera, R; Koesterke, L; Edvardsson, B; Castelli, F; Plez, B; Bizyaev, D; Cunha, K; Perez, A E Garcia; Gustafsson, B; Holtzman, J A; Lawler, J E; Majewski, S R; Manchado, A; Meszaros, Sz; Shane, N; Shetrone, M; Smith, V V; Zasowski, G

    2015-01-01

    The Sloan Digital Sky Survey--III (SDSS--III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) has obtained high resolution (R $\\sim$ 22,500), high signal-to-noise ($>$ 100) spectra in the H$-$band spectral region ($\\sim$1.5$-$1.7 $\\mu$m) for about 146,000 stars in the Milky Way galaxy. We have computed specific spectral libraries with effective temperature ($T\\rm{_{eff}}$) ranging from 3500 to 8000 K for the automated chemical analysis of the survey data. The spectral libraries, used to derive stellar parameters and abundances from the APOGEE spectra in the SDSS--III data release 12 (DR12), are based on ATLAS9 model atmospheres and the ASS$\\epsilon$T spectral synthesis code. We present a second set of stellar spectral libraries based on MARCS model atmospheres and the spectral synthesis code Turbospectrum. The ATLAS9/ASS$\\epsilon$T ($T\\rm{_{eff}}$ = 3500$-$8000 K) and MARCS/Turbospectrum ($T\\rm{_{eff}}$ = 3500$-$5500 K) grids of synthetic spectra cover a wide range of metallicity ($-$2.5 $\\leq...

  20. Abundances, Stellar Parameters, and Spectra From the SDSS-III/APOGEE Survey

    CERN Document Server

    Holtzman, Jon A; Johnson, Jennifer A; Prieto, Carlos Allende; Anders, Friedrich; Andrews, Brett; Beers, Timothy C; Bizyaev, Dmitry; Blanton, Michael R; Bovy, Jo; Carrera, Ricardo; Cunha, Katia; Eisenstein, Daniel J; Feuillet, Diane; Frinchaboy, Peter M; Galbraith-Frew, Jessica; Perez, Ana E Garcia; Hernandez, D Anibal Garcia; Hasselquist, Sten; Hayden, Michael R; Hearty, Fred R; Ivans, Inese; Majewski, Steven R; Martell, Sarah; Meszaros, Szabolcs; Muna, Demitri; Nidever, David L; Nguyen, Duy Cuong; O'Connell, Robert W; Pan, Kaike; Pinsonneault, Marc; Robin, Annie C; Schiavon, Ricardo P; Shane, Neville; Sobeck, Jennifer; Smith, Verne V; Troup, Nicholas; Weinberg, David H; Wilson, John C; Wood-Vasey, W M; Zamora, Olga; Zasowski, Gail

    2015-01-01

    The SDSS-III/APOGEE survey operated from 2011-2014 using the APOGEE spectrograph, which collects high-resolution (R~22,500), near-IR (1.51-1.70 microns) spectra with a multiplexing (300 fiber-fed objects) capability. We describe the survey data products that are publicly available, which include catalogs with radial velocity, stellar parameters, and 15 elemental abundances for over 150,000 stars, as well as the more than 500,000 spectra from which these quantities are derived. Calibration relations for the stellar parameters (Teff, log g, [M/H], [alpha/M]) and abundances (C, N, O, Na, Mg, Al, Si, S, K, Ca, Ti, V, Mn, Fe, Ni) are presented and discussed. The internal scatter of the abundances within clusters indicates that abundance precision is generally between 0.05 and 0.09 dex across a broad temperature range; within more limited ranges and at high S/N, it is smaller for some elemental abundances. We assess the accuracy of the abundances using comparison of mean cluster metallicities with literature values...

  1. The Comparison of Stellar Atomspheric Parameters between LAMOST and APOGEE databases

    CERN Document Server

    Chen, Y Q; Liu, C; Ren, J; Jia, Y P; Zhao, J K; Luo, A L; Zhang, Y; Hou, Y H; Wang, Y F; Yang, M

    2015-01-01

    We have compared the stellar parameters, temperature, gravity and metallicity, between the LAMOST-DR2 and SDSS-DR12/APOGEE database for stars in common. It is found that the LAMOST database provides a better red-clump feature than the APOGEE database in the Teff versus logg diagram. With this advantage, we have separated red clump stars from red giant stars, and attempt to establish the calibrations between the two datasets for the two groups of stars respectively. It shows that there is a good consistency in temperature with a calibration close to the one-to-one line, and we can establish a satisfied metallicity calibration of [Fe/H]_APO=1.18[Fe/H]_APO+0.11 with a scatter of 0.08 dex for both red clump and red giant branch samples. For gravity, there is no any correlation for red clump stars between the two databases, and scatters around the calibrations of red giant stars are substantial. We found two main sources of the scatters of logg for red giant stars. One is a group of stars with $0.00253*Teff-8.67-1...

  2. The APOGEE Spectroscopic Survey of Kepler Planet Hosts: Feasibility, Efficiency, and First Results

    CERN Document Server

    Fleming, Scott W; Deshpande, Rohit; Bender, Chad F; Terrien, Ryan C; Marchwinski, Robert C; Wang, Ji; Roy, Arpita; Stassun, Keivan G; Prieto, Carlos Allende; Cunha, Katia; Smith, Verne V; Agol, Eric; Ak, Hasan; Bastien, Fabienne A; Bizyaev, Dmitry; Crepp, Justin R; Ford, Eric B; Frinchaboy, Peter M; García-Hernández, Domingo Aníbal; Pérez, Ana Elia García; Gaudi, B Scott; Ge, Jian; Hearty, Fred; Ma, Bo; Majewski, Steve R; Mészáros, Szabolcs; Nidever, David L; Pan, Kaike; Pepper, Joshua; Pinsonneault, Marc H; Schiavon, Ricardo P; Schneider, Donald P; Wilson, John C; Zamora, Olga; Zasowski, Gail

    2015-01-01

    The Kepler mission has yielded a large number of planet candidates from among the Kepler Objects of Interest (KOIs), but spectroscopic follow-up of these relatively faint stars is a serious bottleneck in confirming and characterizing these systems. We present motivation and survey design for an ongoing project with the SDSS-III multiplexed APOGEE near-infrared spectrograph to monitor hundreds of KOI host stars. We report some of our first results using representative targets from our sample, which include current planet candidates that we find to be false positives, as well as candidates listed as false positives that we do not find to be spectroscopic binaries. With this survey, KOI hosts are observed over ~20 epochs at a radial velocity precision of 100-200 m/s. These observations can easily identify a majority of false positives caused by physically-associated stellar or substellar binaries, and in many cases, fully characterize their orbits. We demonstrate that APOGEE is capable of achieving RV precision ...

  3. Tracing chemical evolution over the extent of the Milky Way's Disk with APOGEE Red Clump Stars

    CERN Document Server

    Nidever, David L; Bird, Jonathan C; Andrews, Brett H; Hayden, Michael; Holtzman, Jon; Majewski, Steven R; Smith, Verne; Robin, Annie C; Perez, Ana E Garcia; Cunha, Katia; Prieto, Carlos Allende; Zasowski, Gail; Schiavon, Ricardo P; Johnson, Jennifer A; Weinberg, David H; Feuillet, Diane; Schneider, Donald P; Shetrone, Matthew; Sobeck, Jennifer; Garcia-Hernandez, D A; Zamora, O; Rix, Hans-Walter; Beers, Timothy C; Wilson, John C; O'Connell, Robert W; Minchev, Ivan; Chiappini, Cristina; Anders, Friedrich; Bizyaev, Dmitry; Brewington, Howard; Ebelke, Garrett; Frinchaboy, Peter M; Ge, Jian; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; Marchante, Moses; Meszaros, Szabolcs; Oravetz, Daniel; Pan, Kaike; Simmons, Audrey; Skrutskie, Michael F

    2014-01-01

    We employ the first two years of data from the near-infrared, high-resolution SDSS-III/APOGEE spectroscopic survey to investigate the distribution of metallicity and alpha-element abundances of stars over a large part of the Milky Way disk. Using a sample of ~10,000 kinematically-unbiased red-clump stars with ~5% distance accuracy as tracers, the [alpha/Fe] vs. [Fe/H] distribution of this sample exhibits a bimodality in [alpha/Fe] at intermediate metallicities, -0.9<[Fe/H]<-0.2, but at higher metallicities ([Fe/H]=+0.2) the two sequences smoothly merge. We investigate the effects of the APOGEE selection function and volume filling fraction and find that these have little qualitative impact on the alpha-element abundance patterns. The described abundance pattern is found throughout the range 5

  4. SODIUM AND OXYGEN ABUNDANCES IN THE OPEN CLUSTER NGC 6791 FROM APOGEE H-BAND SPECTROSCOPY

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, Katia; Souto, Diogo [Observatório Nacional, São Cristóvão, Rio de Janeiro (Brazil); Smith, Verne V. [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Johnson, Jennifer A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Bergemann, Maria [Max-Planck-Institut für Astronomy, D-69117, Heidelberg (Germany); Mészáros, Szabolcs [ELTE Gothard Astrophysical Observatory, H-9704 Szombathely (Hungary); Shetrone, Matthew D. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Prieto, Carlos Allende [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Schiavon, Ricardo P. [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5RF (United Kingdom); Frinchaboy, Peter [Texas Christian University, Fort Worth, TX (United States); Zasowski, Gail [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Bizyaev, Dmitry [Apache Point Observatory, Sunspot, NM 88349 (United States); Holtzman, Jon [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); García Pérez, Ana E.; Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Nidever, David [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Beers, Timothy [Department of Physics and JINA Center for the Evolution of the Elements, University of Notre Dame, Notre Dame, IN 46556 (United States); Carrera, Ricardo [Instituto de Astrofísica de Canarias, La Laguna, E-38200 Tenerife (Spain); Geisler, Doug [Departamento de Astronomia, Casilla 160-C, Universidad de Concepcion (Chile); Gunn, James, E-mail: kcunha@on.br [Department of Astrophysics, Princeton University, Princeton, NJ 08540 (United States); and others

    2015-01-10

    The open cluster NGC 6791 is among the oldest, most massive, and metal-rich open clusters in the Galaxy. High-resolution H-band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) of 11 red giants in NGC 6791 are analyzed for their chemical abundances of iron, oxygen, and sodium. The abundances of these three elements are found to be homogeneous (with abundance dispersions at the level of ∼0.05-0.07 dex) in these cluster red giants, which span much of the red-giant branch (T {sub eff} ∼ 3500-4600 K), and include two red clump giants. From the infrared spectra, this cluster is confirmed to be among the most metal-rich clusters in the Galaxy (([Fe/H]) = 0.34 ± 0.06) and is found to have a roughly solar value of [O/Fe] and slightly enhanced [Na/Fe]. Our non-LTE calculations for the studied Na I lines in the APOGEE spectral region (16373.86 Å and 16388.85 Å) indicate only small departures from LTE (≤0.04 dex) for the parameter range and metallicity of the studied stars. The previously reported double population of cluster members with different Na abundances is not found among the studied sample.

  5. Sodium and Oxygen Abundances in the Open Cluster NGC 6791 from APOGEE H-Band Spectroscopy

    CERN Document Server

    Cunha, Katia; Johnson, Jennifer A; Bergemann, Maria; Meszaros, Szabolcs; Shetrone, Matthew D; Souto, Diogo; Prieto, Carlos Allende; Schiavon, Ricardo P; Frinchaboy, Peter; Zasowski, Gail; Bizyaev, Dmitry; Holtzman, Jon; Perez, Ana E Garcia; Majewski, Steven R; Nidever, David; Beers, Timothy; Carrera, Ricardo; Geisler, Doug; Gunn, James; Hearty, Fred; Ivans, Inese; Martell, Sarah; Pinsonneault, Marc; Schneider, Donald P; Sobeck, Jennifer; Stello, Dennis; Stassun, Keivan G; Skrutskie, Michael; Wilson, John C

    2014-01-01

    The open cluster NGC 6791 is among the oldest, most massive and metal-rich open clusters in the Galaxy. High-resolution $H$-band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) of 11 red giants in NGC 6791 are analyzed for their chemical abundances of iron, oxygen, and sodium. The abundances of these three elements are found to be homogeneous (with abundance dispersions at the level of $\\sim$ 0.05 - 0.07 dex) in these cluster red giants, which span much of the red-giant branch (T$_{\\rm eff}$ $\\sim$ 3500K - 4600K), and include two red-clump giants. From the infrared spectra, this cluster is confirmed to be among the most metal-rich clusters in the Galaxy ($$ = 0.34 $\\pm$ 0.06), and is found to have a roughly solar value of [O/Fe] and slightly enhanced [Na/Fe]. Non-LTE calculations for the studied Na I lines in the APOGEE spectral region ($\\lambda$16373.86\\AA\\ and $\\lambda$16388.85\\AA) indicate only small departures from LTE ($\\leq$ 0.04 dex) for the parameter range and metallic...

  6. An advanced generation land mobile satellite system and its critical technologies

    Science.gov (United States)

    Naderi, F.

    1982-01-01

    A conceptual design for a Land Mobile Satellite System (LMSS) for the 1990s is presented. LMSS involves small tranceivers accessing satellites directly, with ground reception through small car-top antennas. The satellite would have a large antenna and blanket coverage areas in the UHF. The call may originate from a home, be carried by wire to a gateway, transmitted to satellite on the S-band, converted to UHF on the satellite, and transmitted to the vehicle. The system design is constrained by the number of users in an area during the busiest hours, Shuttle storage, controllability factors, and the total area served. A 55-m antenna has been selected, with 87 spot beams and two 10 MHz UHF bands in the 806-890 MHz band. A 17 dB interbeam isolation level is required, implying that sufficient sub-bands can be generated to assure 8265 total channels. The mobile satellite (MSAT) would have an 83 m mast lower segment, a 34 m upper segment, and a second, 10 m antenna made of a deployable mesh. Various antenna function modes are considered.

  7. A technique for measurement of earth station antenna G/T by radio stars and Applications Technology Satellites.

    Science.gov (United States)

    Kochevar, H. J.

    1972-01-01

    A new technique has been developed to accurately measure the G/T of a small aperture antenna using geostationary satellites and the well established radio star method. A large aperture antenna having the capability of accurately measuring its G/T by using a radio star of known power density is used to obtain an accurate G/T to use as a reference. The CNR of both the large and small aperture antennas are then measured using an Applications Technology Satellite (ATS). After normalizing the two C/N ratios to the large antenna system noise temperature the G/T or the gain G of the small aperture antenna can then be determined.

  8. Using Enabling Technologies to Facilitate the Comparison of Satellite Observations with the Model Forecasts for Hurricane Study

    Science.gov (United States)

    Li, P.; Knosp, B.; Hristova-Veleva, S. M.; Niamsuwan, N.; Johnson, M. P.; Shen, T. P. J.; Tanelli, S.; Turk, J.; Vu, Q. A.

    2014-12-01

    Due to their complexity and volume, the satellite data are underutilized in today's hurricane research and operations. To better utilize these data, we developed the JPL Tropical Cyclone Information System (TCIS) - an Interactive Data Portal providing fusion between Near-Real-Time satellite observations and model forecasts to facilitate model evaluation and improvement. We have collected satellite observations and model forecasts in the Atlantic Basin and the East Pacific for the hurricane seasons since 2010 and supported the NASA Airborne Campaigns for Hurricane Study such as the Genesis and Rapid Intensification Processes (GRIP) in 2010 and the Hurricane and Severe Storm Sentinel (HS3) from 2012 to 2014. To enable the direct inter-comparisons of the satellite observations and the model forecasts, the TCIS was integrated with the NASA Earth Observing System Simulator Suite (NEOS3) to produce synthetic observations (e.g. simulated passive microwave brightness temperatures) from a number of operational hurricane forecast models (HWRF and GFS). An automated process was developed to trigger NEOS3 simulations via web services given the location and time of satellite observations, monitor the progress of the NEOS3 simulations, display the synthetic observation and ingest them into the TCIS database when they are done. In addition, three analysis tools, the joint PDF analysis of the brightness temperatures, ARCHER for finding the storm-center and the storm organization and the Wave Number Analysis tool for storm asymmetry and morphology analysis were integrated into TCIS to provide statistical and structural analysis on both observed and synthetic data. Interactive tools were built in the TCIS visualization system to allow the spatial and temporal selections of the datasets, the invocation of the tools with user specified parameters, and the display and the delivery of the results. In this presentation, we will describe the key enabling technologies behind the design of

  9. Accelerated life tests of specimen heat pipe from Communication Technology Satellite (CTS) project

    Science.gov (United States)

    Tower, L. K.; Kaufman, W. B.

    1977-01-01

    A gas-loaded variable conductance heat pipe of stainless steel with methanol working fluid identical to one now on the CTS satellite was life tested in the laboratory at accelerated conditions for 14 200 hours, equivalent to about 70 000 hours at flight conditions. The noncondensible gas inventory increased about 20 percent over the original charge. The observed gas increase is estimated to increase operating temperature by about 2.2 C, insufficient to harm the electronic gear cooled by the heat pipes in the satellite. Tests of maximum heat input against evaporator elevation agree well with the manufacturer's predictions.

  10. Research of Multi-Agent System based satellite fault diagnosis technology

    Institute of Scientific and Technical Information of China (English)

    范显峰; 姜兴渭; 黄文虎; 谷吉海

    2002-01-01

    Following the theory of Multi-Agent System (MAS) and using series-wound structure and shunt-wound structure of Agents, the performance of Agent was improved to satisfy the need of satellite fault diagno-sis, and a tridimensional MAS model of satellite fault diagnosis was thus established for the MAS based planardiagnosis system, which decentralizes the whole diagnosing task into subtasks to be performed by different func-tional Agents to make the complicated fault diagnosis very simple and the diagnosis system more intelligent.This method improved the reliability and accuracy of diagnosis and made the maintenance and upgrading of thesatellite fault diagnosis system very easy as well.

  11. A steady tracking technology adopted to fast FH/BPSK signal under satellite channel

    Science.gov (United States)

    Guo, SuLi; Lou, Zhigang; Wang, XiDuo; Xia, ShuangZhi

    2015-07-01

    In order to survive under the conditions with great jamming and interference, fast frequency hopped signal are employed in satellite communication system. This paper discusses the nonlinear phases induced by the equipment and atmosphere, and their influence on the FFH/BPSK tracking loop. Two methods are developed including compensating phase which is based on channel estimation and compensating Doppler frequency based on velocity normalization. Simulation results for a real circuit with proper parameters shows that the degradation due to the demodulation of frequency-hopped is only a fraction of one dB in an AWGN environment under satellite channel.

  12. Submicrosecond comparisons of time standards via the Navigation Technology Satellites (NTS)

    Science.gov (United States)

    Buisson, J. A.; Mccaskill, T.; Oaks, J.; Lynch, D.; Wardrip, S. C.; Whitworth, G.

    1978-01-01

    An interim demonstration was performed of the time transfer capability of the NAVSTAR GPS system using a single NTS satellite. Measurements of time difference (pseudo-range) are made from the NTS tracking network and at the participating observatories. The NTS network measurements are used to compute the NTS orbit trajectory. The central NTS tracking station has a time link to the Naval Observatory UTC (USNO,MC1) master clock. Measurements are used with the NTS receiver at the remote observatory, the time transfer value UTC (USNO,MC1)-UTC (REMOTE, VIA NTS) is calculated. Intercomparisons were computed using predicted values of satellite clock offset and ephemeus.

  13. New H-band Stellar Spectral Libraries for the SDSS-III/APOGEE Survey

    Science.gov (United States)

    Zamora, O.; García-Hernández, D. A.; Allende Prieto, C.; Carrera, R.; Koesterke, L.; Edvardsson, B.; Castelli, F.; Plez, B.; Bizyaev, D.; Cunha, K.; García Pérez, A. E.; Gustafsson, B.; Holtzman, J. A.; Lawler, J. E.; Majewski, S. R.; Manchado, A.; Mészáros, Sz.; Shane, N.; Shetrone, M.; Smith, V. V.; Zasowski, G.

    2015-06-01

    The Sloan Digital Sky Survey-III (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE) has obtained high-resolution (R ˜ 22,500), high signal-to-noise ratio (\\gt 100) spectra in the H-band (˜1.5-1.7 μm) for about 146,000 stars in the Milky Way galaxy. We have computed spectral libraries with effective temperature ({{T}eff}) ranging from 3500 to 8000 K for the automated chemical analysis of the survey data. The libraries, used to derive stellar parameters and abundances from the APOGEE spectra in the SDSS-III data release 12 (DR12), are based on ATLAS9 model atmospheres and the ASSɛT spectral synthesis code. We present a second set of libraries based on MARCS model atmospheres and the spectral synthesis code Turbospectrum. The ATLAS9/ASSɛT ({{T}eff} = 3500-8000 K) and MARCS/Turbospectrum ({{T}eff} = 3500-5500 K) grids cover a wide range of metallicity (-2.5 ≤slant [M/H] ≤slant +0.5 dex), surface gravity (0 ≤ log g ≤slant 5 dex), microturbulence (0.5 ≤slant ξ ≤slant 8 km s-1), carbon (-1 ≤slant [C/M] ≤slant +1 dex), nitrogen (-1 ≤slant [N/M] ≤slant +1 dex), and α-element (-1 ≤slant [α/M] ≤slant +1 dex) variations, having thus seven dimensions. We compare the ATLAS9/ASSɛT and MARCS/Turbospectrum libraries and apply both of them to the analysis of the observed H-band spectra of the Sun and the K2 giant Arcturus, as well as to a selected sample of well-known giant stars observed at very high resolution. The new APOGEE libraries are publicly available and can be employed for chemical studies in the H-band using other high-resolution spectrographs.

  14. Proceedings of the Seventeenth NASA Propagation Experimenters Meeting (NAPEX 17) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop

    Science.gov (United States)

    Davarian, Faramaz (Editor)

    1993-01-01

    The NASA Propagation Experimenters Meeting (NAPEX) is convened annually to discuss studies made on radio wave propagation by investors from domestic and international organizations. NAPEX 17 was held on 15 June 1993. The meeting was organized into two technical sessions. The first session was dedicated to slant path propagation studies and experiments. The second session focused on propagation studies for mobile and personal communications. Preceding NAPEX 17, the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop was held on 14 June 1993 to review ACTS propagation activities with emphasis on ACTS experiments status and data collection, processing, and exchange.

  15. Communication Satellite Technology as a Potential Comprehensive Delivery System for Correctional Institution Education and Training Programs

    Science.gov (United States)

    Polcyn, Kenneth A.

    1977-01-01

    By pooling resources and using communication satellites to access quality regional or national programs and personnel, institutions may be able to determine inmate aptitudes and career options, receive career counselling for inmates based on job trends, access educational and vocational training programs that match the inmates' capabilities and…

  16. Communication Satellite Technology as a Potential Comprehensive Delivery System for Correctional Institution Education and Training Programs

    Science.gov (United States)

    Polcyn, Kenneth A.

    1977-01-01

    By pooling resources and using communication satellites to access quality regional or national programs and personnel, institutions may be able to determine inmate aptitudes and career options, receive career counselling for inmates based on job trends, access educational and vocational training programs that match the inmates' capabilities and…

  17. APOGEE Chemical Abundances of Globular Cluster Giants in the Inner Galaxy

    CERN Document Server

    Schiavon, Ricardo P; Frinchaboy, Peter M; Zasowski, Gail; Meszaros, Szabolcs; Garcia-Hernandez, D A; Cohen, Roger E; Tang, Baitian; Villanova, Sandro; Geisler, Douglas; Beers, Timothy C; Fernandez-Trincado, J G; Perez, Ana E Garcia; Lucatello, Sara; Majewski, Steven R; Martell, Sarah L; O'Connell, Robert W; Prieto, Carlos Allende; Bizyaev, Dmitry; Carrera, Ricardo; Lane, Richard R; Malanushenko, Elena; Malanushenko, Viktor; Munoz, Ricardo R; Nitschelm, Christian; Oravetz, Daniel; Pan, Kaike; Roman-Lopes, Alexandre; Schultheis, Matthias; Simmons, Audrey

    2016-01-01

    We report chemical abundances obtained by SDSS-III/APOGEE for giant stars in five globular clusters located within 2.2 kpc of the Galactic centre. We detect the presence of multiple stellar populations in four of those clusters (NGC 6553, NGC 6528, Terzan 5, and Palomar 6) and find strong evidence for their presence in NGC 6522. All clusters present a significant spread in the abundances of N, C, Na, and Al, with the usual correlations and anti-correlations between various abundances seen in other globular clusters. Our results provide important quantitative constraints on theoretical models for self-enrichment of globular clusters, by testing their predictions for the dependence of yields of elements such as Na, N, C, and Al on metallicity. They also confirm that, under the assumption that field N-rich stars originate from globular cluster destruction, they can be used as tracers of their parental systems in the high- metallicity regime.

  18. Testing the Asteroseismic Mass Scale Using Metal-Poor Stars Characterized with APOGEE and Kepler

    CERN Document Server

    Epstein, Courtney R; Johnson, Jennifer A; Shetrone, Matthew; Mosser, Benoît; Hekker, Saskia; Tayar, Jamie; Harding, Paul; Pinsonneault, Marc; Aguirre, Víctor Silva; Basu, Sarbani; Beers, Timothy C; Bizyaev, Dmitry; Bedding, Timothy R; Chaplin, William J; Frinchaboy, Peter M; García, Rafael A; Pérez, Ana E García; Hearty, Fred R; Huber, Daniel; Ivans, Inese I; Majewski, Steven R; Mathur, Savita; Nidever, David; Serenelli, Aldo; Schiavon, Ricardo P; Schneider, Donald P; Schönrich, Ralph; Sobeck, Jennifer S; Stassun, Keivan G; Stello, Dennis; Zasowski, Gail

    2014-01-01

    Fundamental stellar properties, such as mass, radius, and age, can be inferred using asteroseismology. Cool stars with convective envelopes have turbulent motions that can stochastically drive and damp pulsations. The properties of the oscillation frequency power spectrum can be tied to mass and radius through solar-scaled asteroseismic relations. Stellar properties derived using these scaling relations need verification over a range of metallicities. Because the age and mass of halo stars are well-constrained by astrophysical priors, they provide an independent, empirical check on asteroseismic mass estimates in the low-metallicity regime. We identify nine metal-poor red giants (including six stars that are kinematically associated with the halo) from a sample observed by both the Kepler space telescope and the Sloan Digital Sky Survey-III APOGEE spectroscopic survey. We compare masses inferred using asteroseismology to those expected for halo and thick-disk stars. Although our sample is small, standard scal...

  19. VizieR Online Data Catalog: IN-SYNC. I. APOGEE stellar parameters (Cottaar+, 2014)

    Science.gov (United States)

    Cottaar, M.; Covey, K. R.; Meyer, M. R.; Nidever, D. L.; Stassun, K. G.; Foster, J. B.; Tan, J. C.; Chojnowski, S. D.; da Rio, N.; Flaherty, K. M.; Frinchaboy, P. M.; Skrutskie, M.; Majewski, S. R.; Wilson, J. C.; Zasowski, G.

    2015-06-01

    The spectra were collected with APOGEE's multi-object, high-resolution (R~22500) spectrograph with a spectral range covering much of the H band from 1.51 to 1.69um, which is fiber-fed from the Sloan 2.5m telescope. We provide two companion tables to this paper, which contain the derived stellar parameters for the stars in IC 348 and the Pleiades. The first table contains one row per star with the mean spectral and photometric parameters. The second table contains one row per epoch with the spectral parameters measured at that epoch. In both tables we provide the uncertainties computed by Equation (5). (2 data files).

  20. Tidal Interaction among Red Giants Close Binary Systems in APOGEE Database

    Science.gov (United States)

    Sun, Meng; Arras, Phil; Majewski, Steven R.; Troup, Nicholas William; Weinberg, Nevin N.

    2017-01-01

    Motivated by the newly discovered close binary systems in the Apache Point Observatory Galactic Evolution Experiment (APOGEE-1), the tidal evolution of binaries containing a red giant branch (RGB) star with a stellar or substellar companion was investigated. The tide raised by the companion in the RGB star leads to exchange of angular momentum between the orbit and the stellar spin, causing the orbit to contract. The tidal dissipation rate is computed using turbulent viscosity acting on the equilibrium tidal flow, where careful attention is paid to the effects of reduced viscosity for close-in companions. Evolutionary models for the RGB stars, from the zero-age main sequence to the present, were acquired from the MESA code. "Standard" turbulent viscosity gives rise to such a large orbital decay that many observed systems have decay times much shorter than the RGB evolution time. Several theories for "reduced" turbulent viscosity are investigated, and reduce the number of systems with uncomfortably short decay times.

  1. Infrared High-Resolution Integrated Light Spectral Analyses of M31 Globular Clusters from APOGEE

    CERN Document Server

    Sakari, Charli M; Schiavon, Ricardo P; Bizyaev, Dmitry; Prieto, Carlos Allende; Beers, Timothy C; Caldwell, Nelson; Garcia-Hernandez, Domingo Anibal; Lucatello, Sara; Majewski, Steven; O'Connell, Robert W; Pan, Kaike; Strader, Jay

    2016-01-01

    Chemical abundances are presented for 25 M31 globular clusters (GCs), based on moderately high resolution (R = 22, 500) H-band integrated light spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Infrared spectra offer lines from new elements, of different strengths, and at higher excitation potentials compared to the optical. Integrated abundances of C, N, and O are derived from CO, CN, and OH molecular features, while Fe, Na, Mg, Al, Si, K, Ca, and Ti abundances are derived from atomic features. These abundances are compared to previous results from the optical, demonstrating the validity and value of infrared integrated light analyses. The CNO abundances are consistent with typical tip of the red giant branch stellar abundances, but are systematically offset from optical, Lick index abundances. With a few exceptions, the other abundances agree between the optical and the infrared within the 1{\\sigma} uncertainties. The first integrated K abundances are also presented, and demo...

  2. Chemical Cartography with APOGEE: Metallicity Distribution Functions and the Chemical Structure of the Milky Way Disk

    CERN Document Server

    Hayden, Michael R; Holtzman, Jon A; Nidever, David L; Bird, Jonathan C; Weinberg, David H; Andrews, Brett H; Prieto, Carlos Allende; Anders, Friedrich; Beers, Timothy C; Bizyaev, Dmitry; Chiappini, Cristina; Cunha, Katia; Frinchaboy, Peter; García-Herńandez, Domingo A; Pérez, Ana E García; Girardi, Léo; Harding, Paul; Hearty, Fred R; Johnson, Jennifer A; Majewski, Steven R; Mészáros, Szabolcs; Minchev, Ivan; O'Connell, Robert; Pan, Kaike; Robin, Annie C; Schiavon, Ricardo P; Schneider, Donald P; Schultheis, Mathias; Shetrone, Matthew; Skrutskie, Michael; Steinmetz, Matthias; Smith, Verne; Zamora, Olga; Zasowski, Gail

    2015-01-01

    Using a sample of 69,919 red giants from the SDSS-III/APOGEE Data Release 12, we measure the distribution of stars in the [$\\alpha$/Fe] vs. [Fe/H] plane and the metallicity distribution functions (MDF) across an unprecedented volume of the Milky Way disk, with radius $311$ kpc. The peak of the midplane MDF shifts to lower metallicity at larger $R$, reflecting the Galactic metallicity gradient. Most strikingly, the shape of the midplane MDF changes systematically with radius, with a negatively skewed distribution at $31$ kpc or [$\\alpha$/Fe]$>0.18$, the MDF shows little dependence on $R$. The positive skewness of the outer disk MDF may be a signature of radial migration; we show that blurring of stellar populations by orbital eccentricities is not enough to explain the reversal of MDF shape but a simple model of radial migration can do so.

  3. Chemical Cartography with APOGEE: Large-scale Mean Metallicity Maps of the Milky Way

    CERN Document Server

    Hayden, Michael R; Bovy, Jo; Majewski, Steven R; Prieto, Carlos Allende; Beers, Timothy C; Cunha, Katia; Frinchaboy, Peter M; Pérez, Ana E García; Girardi, Léo; Hearty, Fred R; Johnson, Jennifer A; Lee, Young Sun; Nidever, David; Schiavon, Ricardo P; Schlesinger, Katharine J; Schneider, Donald P; Schultheis, Mathias; Shetrone, Matthew; Smith, Verne V; Zasowski, Gail; Bizyaev, Dmitry; Feuillet, Diane; Hasselquist, Sten; Kinemuchi, Karen; Malanushenko, Elena; Malanushenko, Viktor; O'Connell, Robert; Pan, Kaike; Stassun, Keivan

    2013-01-01

    We present Galactic mean metallicity maps derived from the first year of the SDSS-III APOGEE experiment. Mean abundances in different zones of Galactocentric radius (0 6 kpc, the gradient flattens as one moves off of the plane, and is flatter at all heights for high-[{\\alpha}/M] stars than for low-[{\\alpha}/M] stars. Alternatively, these gradients can be described as vertical gradients that flatten at larger Galactocentric radius; these vertical gradients are similar for both low and high-[{\\alpha}/M] populations. Stars with higher [{\\alpha}/M] appear to have a flatter radial gradient than stars with lower [{\\alpha}/M]. This could suggest that the metallicity gradient has grown steeper with time or, alternatively, that gradients are washed out over time by migration of stars.

  4. Satellite Communications

    CERN Document Server

    Pelton, Joseph N

    2012-01-01

    The field of satellite communications represents the world's largest space industry. Those who are interested in space need to understand the fundamentals of satellite communications, its technology, operation, business, economic, and regulatory aspects. This book explains all this along with key insights into the field's future growth trends and current strategic challenges. Fundamentals of Satellite Communications is a concise book that gives all of the key facts and figures as well as a strategic view of where this dynamic industry is going. Author Joseph N. Pelton, PhD, former Dean of the International Space University and former Director of Strategic Policy at Intelstat, presents a r

  5. A Catalog of 1.5273 um Diffuse Interstellar Bands Based on APOGEE Hot Telluric Calibrators

    Science.gov (United States)

    Elyajouri, M.; Monreal-Ibero, A.; Remy, Q.; Lallement, R.

    2016-08-01

    High resolution stellar spectroscopic surveys provide massive amounts of diffuse interstellar bands (DIBs) measurements. Data can be used to study the distribution of the DIB carriers and those environmental conditions that favor their formation. In parallel, recent studies have also proved that DIBs extracted from stellar spectra constitute new tools for building the 3D structure of the Galactic interstellar medium (ISM). The amount of details on the structure depends directly on the quantity of available lines of sight. Therefore there is a need to construct databases of high-quality DIB measurements as large as possible. We aim at providing the community with a catalog of high-quality measurements of the 1.5273 μm DIB toward a large fraction of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) hot stars observed to correct for the telluric absorption and not used for ISM studies so far. This catalog would complement the extensive database recently extracted from the APOGEE observations and used for 3D ISM mapping. We devised a method to fit the stellar continuum of the hot calibration stars and extracted the DIB from the normalized spectrum. Severe selection criteria based on the absorption characteristics are applied to the results. In particular limiting constraints on the DIB widths and Doppler shifts are deduced from the H i 21 cm measurements, following a new technique of decomposition of the emission spectra. From ˜16,000 available hot telluric spectra we have extracted ˜6700 DIB measurements and their associated uncertainties. The statistical properties of the extracted absorptions are examined and our selection criteria are shown to provide a robust dataset. The resulting catalog contains the DIB total equivalent widths, central wavelengths and widths. We briefly illustrate its potential use for the stellar and interstellar communities.

  6. VERY METAL-POOR STARS IN THE OUTER GALACTIC BULGE FOUND BY THE APOGEE SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Perez, Ana E.; Majewski, Steven R.; Hearty, Fred R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Cunha, Katia [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Shetrone, Matthew [McDonald Observatory, University of Texas at Austin, Fort Davis, TX 79734 (United States); Johnson, Jennifer A.; Zasowski, Gail [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Smith, Verne V.; Beers, Timothy C. [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Schiavon, Ricardo P. [Gemini Observatory, 670 N. A' Ohoku Place, Hilo, HI 96720 (United States); Holtzman, Jon [Department of Astronomy, MSC 4500, New Mexico State University, P.O. Box 30001, Las Cruces, NM 88003 (United States); Nidever, David [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Allende Prieto, Carlos [Departamento de Astrofisica, Universidad de La Laguna, E-38206 La Laguna, Tenerife (Spain); Bizyaev, Dmitry; Ebelke, Garrett; Malanushenko, Elena; Malanushenko, Viktor [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Eisenstein, Daniel J. [Harvard Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Frinchaboy, Peter M. [Department of Physics and Astronomy, Texas Christian University, 2800 South University Drive, Fort Worth, TX 76129 (United States); Girardi, Leo [Laboratorio Interinstitucional de e-Astronomia - LIneA, Rua Gal. Jose Cristino 77, Rio de Janeiro, RJ - 20921-400 (Brazil); and others

    2013-04-10

    Despite its importance for understanding the nature of early stellar generations and for constraining Galactic bulge formation models, at present little is known about the metal-poor stellar content of the central Milky Way. This is a consequence of the great distances involved and intervening dust obscuration, which challenge optical studies. However, the Apache Point Observatory Galactic Evolution Experiment (APOGEE), a wide-area, multifiber, high-resolution spectroscopic survey within Sloan Digital Sky Survey III, is exploring the chemistry of all Galactic stellar populations at infrared wavelengths, with particular emphasis on the disk and the bulge. An automated spectral analysis of data on 2403 giant stars in 12 fields in the bulge obtained during APOGEE commissioning yielded five stars with low metallicity ([Fe/H] {<=} -1.7), including two that are very metal-poor [Fe/H] {approx} -2.1 by bulge standards. Luminosity-based distance estimates place the 5 stars within the outer bulge, where 1246 of the other analyzed stars may reside. A manual reanalysis of the spectra verifies the low metallicities, and finds these stars to be enhanced in the {alpha}-elements O, Mg, and Si without significant {alpha}-pattern differences with other local halo or metal-weak thick-disk stars of similar metallicity, or even with other more metal-rich bulge stars. While neither the kinematics nor chemistry of these stars can yet definitively determine which, if any, are truly bulge members, rather than denizens of other populations co-located with the bulge, the newly identified stars reveal that the chemistry of metal-poor stars in the central Galaxy resembles that of metal-weak thick-disk stars at similar metallicity.

  7. Observing the products of stellar evolution in the old open cluster M67 with APOGEE

    Science.gov (United States)

    Bertelli Motta, Clio; Salaris, Maurizio; Pasquali, Anna; Grebel, Eva K.

    2017-04-01

    Recent works have shown how the [C/N] ratio in stars after the first dredge-up (FDU) can be used as an age estimator in virtue of its dependence on stellar mass. For this purpose, precise predictions of the surface chemical composition before and after the mixing takes place in the convective envelope of subgiant stars are necessary. Stellar evolution models can provide us with such predictions, although a comparison with objects of known age is needed for calibration. Open clusters are excellent test cases, as they represent a single stellar population for which the age can be derived through, e.g. isochrone fitting. In this study, we present a detailed analysis of stars belonging to the well-known open cluster M67 observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey in the twelfth data release of the Sloan Digital Sky Survey and whose chemical properties were derived with the APOGEE Stellar Parameters and Chemical Abundances Pipeline. We find that the [C/N] abundance of subgiant branch stars is overestimated by ˜0.2 dex due to an offset in the determination of the [N/Fe] abundance. Stars on the red giant branch and red clump are shown not to be affected by this offset. We derive [C/N]FDU = -0.46 ± 0.03 dex, which poses a strong constraint on calibrations of [C/N]FDU as age indicator. We also do not find any clear signature of additional chemical mixing processes that set in after the red giant branch bump. The results obtained for M67 indicate the importance of conducting high-resolution spectroscopic studies of open clusters of different ages in order to establish an accurate age-dating method for field stars.

  8. NASA to launch second business communications satellite

    Science.gov (United States)

    1981-01-01

    The two stage Delta 3910 launch vehicle was chosen to place the second small business satellite (SBS-B) into a transfer orbit with an apogee of 36,619 kilometers and a perigee of 167 km, at an inclination of 27.7 degrees to Earth's equator. The firing and separation sequence and the inertial guidance system are described as well as the payload assist module. Facilities and services for tracking and control by NASA, COMSAT, Intelsat, and SBS are outlined and prelaunch operations are summarized.

  9. Applications Technology Satellite ATS-6 experiment checkout and continuing spacecraft evaluation report

    Science.gov (United States)

    Moore, W.; Prensky, W. (Editor)

    1974-01-01

    The activities of the ATS-6 spacecraft are reviewed. The following subsystems and experiments are summarized: (1) radio beacon experiments; (2) spacecraft attitude precision pointing and slewing adaptive control experiment; (3) satellite instruction television experiment; (4) thermal control subsystem; (5) spacecraft propulsion subsystem; (6) telemetry and control subsystem; (7) millimeter wave experiment; and (8) communications subsystem. The results of performance evaluation of its subsystems and experiments are presented.

  10. Evaluation of the feasibility of security technologies in teleradiology as biometric fingerprint scanners for data exchange over a satellite WAN

    Science.gov (United States)

    Soegner, Peter I.; Helweg, Gernot; Holzer, Heimo; zur Nedden, Dieter

    2000-05-01

    We evaluated the feasibility of fingerprint-scanners in combination with smart cards for personal identification and transmission of encrypted TCP/IP-data-packages via satellite between the university-hospital of Innsbruck and the rural hospital of Reutte. The aim of our study was the proof of the userfriendliness of the SkymedTM technology for security purpose in teleradiology. We examined the time of the personal identification process, the time for the necessary training and the personal satisfaction. The images were sent from the local PACS in Reutte via a Data-Encryption-and-Transmission- Box via satellite from Reutte to Innsbruck. We used an asymmetric bandwidth of 512 kbit/s from Reutte to Innsbruck and 128 kbit/s in the opposite direction. Window NT 4.0- operating PCs were used for the electronical patient record, the medical inquiry of the referring physician and the final report of the radiologist. The images were reported on an UNIX-PACS viewing station. After identification through fingerprint-scanners in combination with the smart card the radiologist was able to open the electronic patient record (EPR) from Reutte and sign with his digital signature his confirmed final report before it was send back to Reutte. The used security technology enables encrypted communication over a WAN, which fulfill data-protection.

  11. Single-event and total-dose effects in geo-stationary transfer orbit during solar-activity maximum period measured by the Tsubasa satellite

    Science.gov (United States)

    Koshiishi, H.; Kimoto, Y.; Matsumoto, H.; Goka, T.

    The Tsubasa satellite developed by the Japan Aerospace Exploration Agency was launched in Feb 2002 into Geo-stationary Transfer Orbit GTO Perigee 500km Apogee 36000km and had been operated well until Sep 2003 The objective of this satellite was to verify the function of commercial parts and new technologies of bus-system components in space Thus the on-board experiments were conducted in the more severe radiation environment of GTO rather than in Geo-stationary Earth Orbit GEO or Low Earth Orbit LEO The Space Environment Data Acquisition equipment SEDA on board the Tsubasa satellite had the Single-event Upset Monitor SUM and the DOSimeter DOS to evaluate influences on electronic devices caused by radiation environment that was also measured by the particle detectors of the SEDA the Standard DOse Monitor SDOM for measurements of light particles and the Heavy Ion Telescope HIT for measurements of heavy ions The SUM monitored single-event upsets and single-event latch-ups occurred in the test sample of two 64-Mbit DRAMs The DOS measured accumulated radiation dose at fifty-six locations in the body of the Tsubasa satellite Using the data obtained by these instruments single-event and total-dose effects in GTO during solar-activity maximum period especially their rapid changes due to solar flares and CMEs in the region from L 1 1 through L 11 is discussed in this paper

  12. Analysis of innovative scenarios and key technologies to perform active debris removal with satellite modules

    OpenAIRE

    Savioli, Livia / LS

    2015-01-01

    It has surely happened sometimes to look at the night sky and catch sight of a small, brighting spot moving like an airplane, but without ashing as usually airplane lights do: it was a satellite. It is always amazing to think that there are objects that continously orbit around Earth, so far from us. Maybe, it is not well-known that they are a lot...thousands...more or less 17,000 those closer to the Earth, to be precise. It is difficult to imagine how so much objects can orbit without touchi...

  13. Air quality estimates in Mediterranean cities using high resolution satellite technologies

    Science.gov (United States)

    Chudnovsky, Alexandra; Lyapustin, Alexei; Wang, Yujie

    2016-04-01

    Satellite imaging is an essential tool for monitoring air pollution because, unlike ground observations, it supplies continuous data with global coverage of terrestrial and atmospheric components. Satellite-based Aerosol Optical Depth (AOD) retrievals reflect particle abundance in the atmospheric column. This data provide some indication on the extent of particle concentrations. However, it is difficult to retrieve AOD at high spatial resolution above areas with high surface reflectance and heterogeneous land cover, such as urban areas. Therefore, many crowded regions worldwide including Israel, AOD climatology are still uncertain because of the high ground reflectance and coarse spatial resolution. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. This study aims to investigate the spatial variability of AOD within Israeli and several other Mediterranean cities. In addition, we aim to characterize the impact of climatic condition on pollution patterns in-and-between cities and to identify days when cities exhibit the highest variability in AOD. Furthermore, we assessed the differences in pollution levels between adjacent locations. We will report on spatial variability in AOD levels derived from high 1km resolution MAIAC AOD algorithm on a temporal basis, in relation to season and synoptic-meteorological conditions.

  14. Modeling Stellar Parameters for High Resolution Late-M and Early-L Dwarf SDSS/APOGEE Spectra

    Science.gov (United States)

    Birky, Jessica L.; Aganze, Christian; Burgasser, Adam J.; Theissen, Christopher; Schmidt, Sarah J.; Teske, Johanna K.; Stassun, Keivan G.; Bird, Jonathan C.; UCSD FAST Team

    2017-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) of the Sloan Digital Sky Survey IV has measured high resolution (R~22,500), near-infrared (1.51-1.70 µm) spectra for nearly 100,000 stars within the Milky Way Galaxy. While the APOGEE experiment was designed to research Galactic structure by targeting bright stellar populations in the disk, we have focused attention on the lesser-studied subset of faint and low-temperature late-M and early-L dwarfs, with the objective of characterizing their chemical abundances. Using spectral synthesis routines from the Starfish package, we report preliminary determinations of Teff, logg, and [Fe/H] for a small sample of spectra using PHOENIX models ranging in the 2,300 to 3,000K temperature grids.This work is supported by the SDSS Faculty and Student (FAST) initiative, funded by the Alfred P. Sloan Foundation.

  15. Application of the advanced communications technology satellite to teleradiology and real-time compressed ultrasound video telemedicine.

    Science.gov (United States)

    Stewart, B K; Carter, S J; Cook, J N; Abbe, B S; Pinck, D; Rowberg, A H

    1999-05-01

    The authors have investigated the application of the NASA Advanced Communications Technology Satellite (ACTS) to teleradiology and telemedicine using the Jet Propulsion Laboratory (JPL)-developed ACTS Mobile Terminal (AMT) uplink. In this experiment, bidirectional 128, 256, and 384 kbps satellite links were established between the ACTS/AMT, the ACTS in geosynchronous orbit, and the downlink terrestrial terminal at JPL. A terrestrial Integrated Digital Services Network (ISDN) link was established from JPL to the University of Washington Department of Radiology to complete the bidirectional connection. Ultrasound video imagery was compressed in real-time using video codecs adhering to the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) Recommendation H.261. A 16 kbps in-band audio channel was used throughout. A five-point Likert scale was used to evaluate the quality of the compressed ultrasound imagery at the three transmission bandwidths (128, 256, and 384 kbps). The central question involved determination of the bandwidth requirements to provide sufficient spatial and contrast resolution for the remote visualization of fine- and low-contrast objects. The 384 kbps bandwidth resulted in only slight tiling artifact and fuzziness owing to the quantizer step size; however, these motion artifacts were rapidly resolved in time at this bandwidth. These experiments have demonstrated that real-time compressed ultrasound video imagery can be transmitted over multiple ISDN line bandwidth links with sufficient temporal, contrast, and spatial resolution for clinical diagnosis of multiple disease and pathology states to provide subspecialty consultation and educational at a distance.

  16. Chemical Abundances of M-dwarfs from the APOGEE Survey. I. The Exoplanet Hosting Stars Kepler-138 and Kepler-186

    Science.gov (United States)

    Souto, D.; Cunha, K.; García-Hernández, D. A.; Zamora, O.; Allende Prieto, C.; Smith, V. V.; Mahadevan, S.; Blake, C.; Johnson, J. A.; Jönsson, H.; Pinsonneault, M.; Holtzman, J.; Majewski, S. R.; Shetrone, M.; Teske, J.; Nidever, D.; Schiavon, R.; Sobeck, J.; García Pérez, A. E.; Gómez Maqueo Chew, Y.; Stassun, K.

    2017-02-01

    We report the first detailed chemical abundance analysis of the exoplanet-hosting M-dwarf stars Kepler-138 and Kepler-186 from the analysis of high-resolution (R ∼ 22,500) H-band spectra from the SDSS-IV–APOGEE survey. Chemical abundances of 13 elements—C, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, and Fe—are extracted from the APOGEE spectra of these early M-dwarfs via spectrum syntheses computed with an improved line list that takes into account H2O and FeH lines. This paper demonstrates that APOGEE spectra can be analyzed to determine detailed chemical compositions of M-dwarfs. Both exoplanet-hosting M-dwarfs display modest sub-solar metallicities: [Fe/H]Kepler-138 = ‑0.09 ± 0.09 dex and [Fe/H]Kepler-186 = ‑0.08 ± 0.10 dex. The measured metallicities resulting from this high-resolution analysis are found to be higher by ∼0.1–0.2 dex than previous estimates from lower-resolution spectra. The C/O ratios obtained for the two planet-hosting stars are near-solar, with values of 0.55 ± 0.10 for Kepler-138 and 0.52 ± 0.12 for Kepler-186. Kepler-186 exhibits a marginally enhanced [Si/Fe] ratio.

  17. Experiences in Applying Earth Observing Satellite Technology in SERVIR Regions with an Emphasis on Disasters: Successes, Lessons and Paths Forward

    Science.gov (United States)

    Anderson, Eric

    2017-01-01

    Earth observing satellites offer a unique perspective of our environment from the vantage point of space. Repeated measurements of the Earths subsystems such as the biosphere, atmosphere, lithosphere, hydrosphere, and of humans interactions with their environments, allow for a better understanding of Earth system processes, and they can provide input for decision making in areas of environmental management and disaster risk reduction. SERVIR is a joint initiative of the US National Aeronautics and Space Administration (NASA) and the US Agency for International Development (USAID) that began in 2005 and has been active in applying Earth observations for sustainable development in many regions around the world, recently the Lower Mekong and West Africa regions. This talk will highlight some successes achieved and lessons learned through SERVIR in Central America, Eastern Southern Africa, and the Hindu Kush-Himalaya region, focusing on disasters. We will also present opportunities for enhanced decision making with Earth observations and geospatial technologies in the Lower Mekong region.

  18. Robust adjustment of a geodetic network measured by satellite technology in the Dargovských Hrdinov suburb

    Directory of Open Access Journals (Sweden)

    Slavomír Labant

    2011-12-01

    Full Text Available This article addresses the adjustment of a 3D geodetic network in the Dargovských Hrdinov suburbs using Global Navigation SatelliteSystems (GNSS for the purposes of deformation analysis. The advantage of using the GNSS compared to other terrestrial technology is thatit is not influenced by unpredictability in the ground level atmosphere and individual visibilities between points in the observed network arenot necessary. This article also includes the planning of GNSS observations using Planning Open Source software from Trimble as well assubsequent observations at individual network points. The geodetic network is processing on the basis of the Gauss-Markov model usingthe least square method and robust adjustment. From robust methods, Huber’s Robust M-estimation and Hampel’s Robust M-estimationwere used. Individual adjustments were tested and subsequently the results of analysis were graphically visualised using absolute confidenceellipsoids.

  19. Chemical Abundances in a Sample of Red Giants in the Open Cluster NGC 2420 from APOGEE

    CERN Document Server

    Souto, Diogo; Smith, Verne; Prieto, Carlos Allende; Pinsonneault, Marc; Zamora, Olga; García-Hernández, D Anibal; Bovy, Szabolcs Meszaros Jo; Pérez, Ana Elia García; Anders, Friedrich; Bizyaev, Dmitry; Carrera, Ricardo; Frinchaboy, Peter; Holtzman, Jon; Ivans, Inese; Majewski, Steve; Shetrone, Matthew; Sobeck, Jennifer; Pan, Kaike; Tang, Baitian; Villanova, Sandro; Geisler, Douglas

    2016-01-01

    NGC 2420 is a $\\sim$2 Gyr-old well-populated open cluster that lies about 2 kpc beyond the solar circle, in the general direction of the Galactic anti-center. Most previous abundance studies have found this cluster to be mildly metal-poor, but with a large scatter in the obtained metallicities for this open cluster. Detailed chemical abundance distributions are derived for 12 red-giant members of NGC 2420 via a manual abundance analysis of high-resolution (R = 22,500) near-infrared ($\\lambda$1.5 - 1.7$\\mu$m) spectra obtained from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. The sample analyzed contains 6 stars that are identified as members of the first-ascent red giant branch (RGB), as well as 6 members of the red clump (RC). We find small scatter in the star-to-star abundances in NGC 2420, with a mean cluster abundance of [Fe/H] = -0.16 $\\pm$ 0.04 for the 12 red giants. The internal abundance dispersion for all elements (C, N, O, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Co and Ni...

  20. Infrared High-resolution Integrated Light Spectral Analyses of M31 Globular Clusters from APOGEE

    Science.gov (United States)

    Sakari, Charli M.; Shetrone, Matthew D.; Schiavon, Ricardo P.; Bizyaev, Dmitry; Allende Prieto, Carlos; Beers, Timothy C.; Caldwell, Nelson; Aníbal García-Hernández, Domingo; Lucatello, Sara; Majewski, Steven; O'Connell, Robert W.; Pan, Kaike; Strader, Jay

    2016-10-01

    Chemical abundances are presented for 25 M31 globular clusters (GCs), based on moderately high resolution (R = 22,500) H-band integrated light (IL) spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE). Infrared (IR) spectra offer lines from new elements, lines of different strengths, and lines at higher excitation potentials compared to the optical. Integrated abundances of C, N, and O are derived from CO, CN, and OH molecular features, while Fe, Na, Mg, Al, Si, K, Ca, and Ti abundances are derived from atomic features. These abundances are compared to previous results from the optical, demonstrating the validity and value of IR IL analyses. The CNO abundances are consistent with typical tip of the red giant branch stellar abundances but are systematically offset from optical Lick index abundances. With a few exceptions, the other abundances agree between the optical and the IR within the 1σ uncertainties. The first integrated K abundances are also presented and demonstrate that K tracks the α elements. The combination of IR and optical abundances allows better determinations of GC properties and enables probes of the multiple populations in extragalactic GCs. In particular, the integrated effects of the Na/O anticorrelation can be directly examined for the first time.

  1. Development of a large mosaic volume phase holographic (VPH) grating for APOGEE

    Science.gov (United States)

    Arns, James; Wilson, John C.; Skrutskie, Mike; Smee, Steve; Barkhouser, Robert; Eisenstein, Daniel; Gunn, Jim; Hearty, Fred; Harding, Al; Maseman, Paul; Holtzman, Jon; Schiavon, Ricardo; Gillespie, Bruce; Majewski, Steven

    2010-07-01

    Volume phase holographic (VPH) gratings are increasingly being used as diffractive elements in astronomical instruments due to their potential for very high peak diffraction efficiencies and the possibility of a compact instrument design when the gratings are used in transmission. Historically, VPH grating (VPHG) sizes have been limited by the size of manufacturer's holographic recording optics. We report on the design, specification and fabrication of a large, 290 mm × 475 mm elliptically-shaped, mosaic VPHG for the Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectrograph. This high-resolution near-infrared multi-object spectrograph is in construction for the Sloan Digital Sky Survey III (SDSS III). The 1008.6 lines/mm VPHG was designed for optimized performance over a wavelength range from 1.5 to 1.7 μm. A step-and-repeat exposure method was chosen to fabricate a three-segment mosaic on a 305 mm × 508 mm monolithic fused-silica substrate. Specification considerations imposed on the VPHG to assure the mosaic construction will satisfy the end use requirements are discussed. Production issues and test results of the mosaic VPHG are discussed.

  2. Chemical abundance gradients from open clusters in the Milky Way disk: results from the APOGEE survey

    CERN Document Server

    Cunha, Katia; Souto, Diogo; Thompson, Benjamin; Zasowski, Gail; Prieto, Carlos Allende; Carrera, Ricardo; Chiappini, Cristina; Donor, John; Garcia-Hernandez, Anibal; Perez, Ana Elia Garcia; Hayden, Michael R; Holtzman, Jon; Jackson, Kelly M; Johnson, Jennifer A; Majewski, Steven R; Meszaros, Szabolcs; Meyer, Brianne; Nidever, David L; O'Connell, Julia; Schiavon, Ricardo P; Schultheis, Mathias; Shetrone, Matthew; Simmons, Audrey; Smith, Verne V; Zamora, Olga

    2016-01-01

    Metallicity gradients provide strong constraints for understanding the chemical evolution of the Galaxy. We report on radial abundance gradients of Fe, Ni, Ca, Si, and Mg obtained from a sample of 304 red-giant members of 29 disk open clusters, mostly concentrated at galactocentric distances between ~8 - 15 kpc, but including two open clusters in the outer disk. The observations are from the APOGEE survey. The chemical abundances were derived automatically by the ASPCAP pipeline and these are part of the SDSS III Data Release 12. The gradients, obtained from least squares fits to the data, are relatively flat, with slopes ranging from -0.026 to -0.033 dex/kpc for the alpha-elements [O/H], [Ca/H], [Si/H] and [Mg/H] and -0.035 dex/kpc and -0.040 dex/kpc for [Fe/H] and [Ni/H], respectively. Our results are not at odds with the possibility that metallicity ([Fe/H]) gradients are steeper in the inner disk (R_GC ~7 - 12 kpc) and flatter towards the outer disk. The open cluster sample studied spans a significant ran...

  3. Galactic Archaeology with asteroseismology and spectroscopy: Red giants observed by CoRoT and APOGEE

    CERN Document Server

    Anders, F; Rodrigues, T S; Miglio, A; Montalbán, J; Mosser, B; Girardi, L; Valentini, M; Noels, A; Morel, T; Johnson, J A; Schultheis, M; Baudin, F; Peralta, R de Assis; Hekker, S; Themeßl, N; Kallinger, T; García, R A; Mathur, S; Baglin, A; Santiago, B X; Martig, M; Minchev, I; Steinmetz, M; da Costa, L N; Maia, M A G; Prieto, C Allende; Cunha, K; Beers, T C; Epstein, C; Pérez, A E García; García-Hernández, D A; Harding, P; Holtzman, J; Majewski, S R; Mészáros, Sz; Nidever, D; Pan, K; Pinsonneault, M; Schiavon, R P; Schneider, D P; Shetrone, M D; Stassun, K; Zamora, O; Zasowski, G

    2016-01-01

    With the advent of the space missions CoRoT and Kepler, it has become feasible to determine precise asteroseismic masses and ages for large samples of red-giant stars. In this paper, we present the CoRoGEE dataset -- obtained from CoRoT lightcurves for 606 red giant stars in two fields of the Galactic disc which have been co-observed for an ancillary project of APOGEE. We have used the Bayesian parameter estimation code PARAM to calculate distances, extinctions, masses, and ages for these stars in a homogeneous analysis, resulting in relative statistical uncertainties of $\\sim2\\%$ in distance, $\\sim4\\%$ in radius, $\\sim9\\%$ in mass and $\\sim25\\%$ in age. We also assess systematic age uncertainties due to different input physics and mass loss. We discuss the correlation between ages and chemical abundance patterns of field stars over a large radial range of the Milky Way's disc (5 kpc $

  4. Chemodynamics of the Milky Way. I. The first year of APOGEE data

    CERN Document Server

    Anders, F; Santiago, B X; Rocha-Pinto, H J; Girardi, L; da Costa, L N; Maia, M A G; Steinmetz, M; Minchev, I; Schultheis, M; Boeche, C; Miglio, A; Montalbán, J; Schneider, D P; Beers, T C; Cunha, K; Prieto, C Allende; Balbinot, E; Bizyaev, D; Brauer, D E; Brinkmann, J; Frinchaboy, P M; Pérez, A E García; Hayden, M R; Hearty, F R; Holtzman, J; Johnson, J; Kinemuchi, K; Majewski, S R; Malanushenko, E; Malanushenko, V; Nidever, D L; O'Connell, R W; Pan, K; Robin, A C; Schiavon, R P; Shetrone, M; Skrutskie, M F; Smith, V V; Stassun, K; Zasowski, G

    2013-01-01

    We investigate the chemo-kinematic properties of the Milky Way disc by exploring the first year of data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), and compare our results to smaller optical high-resolution samples in the literature, as well as results from lower resolution surveys such as GCS, SEGUE and RAVE. We start by selecting a high-quality sample in terms of chemistry ($\\sim$ 20.000 stars) and, after computing distances and orbital parameters for this sample, we employ a number of useful subsets to formulate constraints on Galactic chemical and chemodynamical evolution processes in the Solar neighbourhood and beyond (e.g., metallicity distributions -- MDFs, [$\\alpha$/Fe] vs. [Fe/H] diagrams, and abundance gradients). Our red giant sample spans distances as large as 10 kpc from the Sun, increasing by at least a factor of eight the studied volume with respect to the most recent chemodynamical studies. We find remarkable agreement between the recently published local (d $<...

  5. Carbon-enhanced metal-poor stars in the SDSS-APOGEE data base

    Science.gov (United States)

    Kielty, C. L.; Venn, K. A.; Loewen, N. B.; Shetrone, M. D.; Placco, V. M.; Jahandar, F.; Mészáros, Sz.; Martell, S. L.

    2017-10-01

    We identify six new carbon-enhanced metal-poor (CEMP) stars ([C/Fe]>+0.7 and [Fe/H] data base following Data Release 12. These stars have chemical compositions typical of metal-poor halo stars, e.g. mean [α/Fe] = +0.24 ± 0.24, based on the APOGEE Stellar Parameters and Chemical Abundances Pipeline results. A lack of heavy-element spectral lines impedes further sub-classification of these CEMP stars, however, based on radial velocity (RV) scatter, we predict most are not CEMP-s stars which are typically found in binary systems. Only one object, 2M15312547+4220551, may be in a binary since it exhibits a scatter in its RV of 1.7 ± 0.6 km s-1 based on three visits over a 25.98 d baseline. Optical observations are now necessary to confirm the stellar parameters and low metallicities of these stars, to determine the heavy-element abundance ratios and improve the precision in the derived abundances, and to examine their CEMP sub-classifications.

  6. Exploring Anticorrelations and Light Element Variations in Northern Globular Clusters Observed by the APOGEE Survey

    CERN Document Server

    Meszaros, Szabolcs; Shetrone, Matthew; Lucatello, Sara; Troup, Nicholas W; Bovy, Jo; Cunha, Katia; Garcia-Hernandez, Domingo A; Overbeek, Jamie C; Prieto, Carlos Allende; Beers, Timothy C; Frinchaboy, Peter M; Perez, Ana E Garcia; Hearty, Fred R; Holtzman, Jon; Majewski, Steven R; Nidever, David L; Schiavon, Ricardo P; Schneider, Donald P; Sobeck, Jennifer S; Smith, Verne V; Zamora, Olga; Zasowski, Gail

    2015-01-01

    We investigate the light-element behavior of red giant stars in Northern globular clusters (GCs) observed by the SDSS-III Apache Point Observatory Galactic Evolution Experiment (APOGEE). We derive abundances of nine elements (Fe, C, N, O, Mg, Al, Si, Ca, and Ti) for 428 red giant stars in 10 globular clusters. The intrinsic abundance range relative to measurement errors is examined, and the well-known C-N and Mg-Al anticorrelations are explored using an extreme-deconvolution code for the first time in a consistent way. We find that Mg and Al drive the population membership in most clusters, except in M107 and M71, the two most metal-rich clusters in our study, where the grouping is most sensitive to N. We also find a diversity in the abundance distributions, with some clusters exhibiting clear abundance bimodalities (for example M3 and M53) while others show extended distributions. The spread of Al abundances increases significantly as cluster average metallicity decreases as previously found by other works, ...

  7. Chemical cartography with apogee: Large-scale mean metallicity maps of the Milky Way disk

    Energy Technology Data Exchange (ETDEWEB)

    Hayden, Michael R.; Holtzman, Jon A.; Lee, Young Sun [New Mexico State University, Las Cruces, NM 88003 (United States); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Majewski, Steven R.; García Pérez, Ana E. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Johnson, Jennifer A. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Allende Prieto, Carlos [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Beers, Timothy C. [Department of Physics and Astronomy and JINA, Joint Institute for Nuclear Astrophysics, Michigan State University, E. Lansing, MI 48824 (United States); Cunha, Katia [Observatório Nacional, São Cristóvão, Rio de Janeiro (Brazil); Frinchaboy, Peter M. [Texas Christian University, Fort Worth, TX 76129 (United States); Girardi, Léo [Osservatorio Astronomico di Padova-INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Hearty, Fred R. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Nidever, David [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Schiavon, Ricardo P. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 ILD (United Kingdom); Schlesinger, Katharine J. [Research School of Astronomy and Astrophysics, Australian National University, Mt. Stromlo Observatory, Cotter Road, Weston, ACT 2611 (Australia); Schneider, Donald P. [Laboratório Interinstitucional de e-Astronomia-LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ - 20921-400 (Brazil); Schultheis, Mathias, E-mail: mrhayden@nmsu.edu, E-mail: holtz@nmsu.edu, E-mail: yslee@nmsu.edu, E-mail: feuilldk@nmsu.edu [Observatoire de la Cote d' Azur, Boulevard de l' Observatoire, B.P. 4229, F-06304 NICE Cedex 4 (France); and others

    2014-05-01

    We present Galactic mean metallicity maps derived from the first year of the SDSS-III APOGEE experiment. Mean abundances in different zones of projected Galactocentric radius (0 < R < 15 kpc) at a range of heights above the plane (0 < |z| < 3 kpc), are derived from a sample of nearly 20,000 giant stars with unprecedented coverage, including stars in the Galactic mid-plane at large distances. We also split the sample into subsamples of stars with low- and high-[α/M] abundance ratios. We assess possible biases in deriving the mean abundances, and find that they are likely to be small except in the inner regions of the Galaxy. A negative radial metallicity gradient exists over much of the Galaxy; however, the gradient appears to flatten for R < 6 kpc, in particular near the Galactic mid-plane and for low-[α/M] stars. At R > 6 kpc, the gradient flattens as one moves off the plane, and is flatter at all heights for high-[α/M] stars than for low-[α/M] stars. Alternatively, these gradients can be described as vertical gradients that flatten at larger Galactocentric radius; these vertical gradients are similar for both low- and high-[α/M] populations. Stars with higher [α/M] appear to have a flatter radial gradient than stars with lower [α/M]. This could suggest that the metallicity gradient has grown steeper with time or, alternatively, that gradients are washed out over time by migration of stars.

  8. The APOGEE DR13 Catalog of Stellar and Substellar Companion Candidates

    Science.gov (United States)

    Troup, Nicholas William; APOGEE RV Variability Working Group

    2017-01-01

    The SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE), expanding beyond its original intent as a Galactic structure survey, has demonstrated its capability as a radial velocity (RV) machine with the publication of a catalog of stellar and substellar companion candidates based on SDSS’s 12th data release (DR12). We expand upon this work by taking advantage of the improved parameters and additional information provided in APOGEE’s latest data release (DR13) to build an improved catalog of stellar and substellar companions. The newly available rotational velocity measurements provides an additional check against false-positive orbital solutions, and aids investigations of the role of tidal interactions in shaping the brown dwarf desert. In addition, we present initial tests of an automated cross-corellation function (CCF) bisector analysis code that allows us to detect spectrally unresolved companions and, in some cases, break the inclination degeneracy of RV detections. Finally, we present analysis of the detailed chemical abundances of the host stars in our sample. In particular, we use this abundance information to disentangle the formation mechanisms of brown dwarf companions from those of gas giant planets and low mass stellar companions.

  9. Environmental Impact Analysis Process. Environmental Assessment for Defense Satellite Communications System III With Integrated Apogee Boost System

    Science.gov (United States)

    1995-07-01

    milkweed E FDA n/o Cocoa nuvifera Coconut palm T FDA o Avicennia germinans Black mangrove SP FCREA o Azolla caroliniana Mosquito fern T FDA o Ernodea...Cumulative Impacts cent. To produce an additional one excess cancer per one million persons, an estimated 0.2 percent reduction in ozone would be nec...FL2800016121. Toxic air pollutants are chemicals that are known to or are suspected of causing cancer or other serious health effects, including

  10. Verification of the Usefulness of the Trimble Rtx Extended Satellite Technology with the Xfill Function in the Local Network Implementing Rtk Measurements

    Science.gov (United States)

    Siejka, Zbigniew

    2014-12-01

    The paper presents the method of satellite measurements, which gives users the ability of GNSS continuous precise positioning in real time, even in the case of short interruptions in receiving the correction of the local ground system of measurements support. The proposed method is a combination of two satellite positioning technologies RTN GNSS and RTX Extended. In technology RTX Extended the xFill function was used for precise positioning in real time and in the local reference system. This function provides the ability to perform measurement without the need for constant communication with the ground support satellite system. Test measurements were performed on a test basis located in Krakow, and RTN GNSS positioning was done based on the national network of reference stations of the ASGEUPOS. The solution allows for short (up to 5 minutes) interruptions in radio or internet communication. When the primary stream of RTN correction is not available, then the global corrections Trimble xFill broadcasted by satellite are used. The new technology uses in the real-time data from the global network of tracking stations and contributes significantly to improving the quality and efficiency of surveying works. At present according to the authors, technology Trimble CenterPoint RTX can guarantee repeatability of measurements not worse than 3.8 cm (Trimble Survey Division, 2012). In the paper the comparative analysis of measurement results between the two technologies was performed: RTN carried out in the classic way, which was based on the corrections of the terrestrial local network of the Polish system of active geodetic network (ASG-EUPOS) and RTK xFill technology. The results were related to the data of test network, established as error free. The research gave satisfactory results and confirmed the great potential of the use of the new technology in the geodetic work realization. By combining these two technologies of GNSS surveying the user can greatly improve the

  11. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2017-01-01

    The first edition of this ground breaking reference work was the most comprehensive reference source available about the key aspects of the satellite applications field. This updated second edition covers the technology, the markets, applications and regulations related to satellite telecommunications, broadcasting and networking—including civilian and military systems; precise satellite navigation and timing networks (i.e. GPS and others); remote sensing and meteorological satellite systems. Created under the auspices of the International Space University based in France, this brand new edition is now expanded to cover new innovative small satellite constellations, new commercial launching systems, innovation in military application satellites and their acquisition, updated appendices, a useful glossary and more.

  12. Experimental Satellite 2 Successfully Launched

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Small satellite Experimental Satellite 2 (SY-2) was launched by LM-2C launch vehicle from Xichang Satellite Launch Center on Nov. 18, 2004. Later the satellite entered the preset sun-synchronous orbit, which is 700 kilometers above the earth. The launch was the eighthmission this year by China Aerospace Science and Technology Corporation(CASC), which aims to test the technology of the satellite, conduct survey and monitoring of the land and resources and geographical environment on a trial basis.

  13. Satellite communication engineering

    CERN Document Server

    Kolawole, Michael Olorunfunmi

    2013-01-01

    An undeniably rich and thorough guide to satellite communication engineering, Satellite Communication Engineering, Second Edition presents the fundamentals of information communications systems in a simple and succinct way. This book considers both the engineering aspects of satellite systems as well as the practical issues in the broad field of information transmission. Implementing concepts developed on an intuitive, physical basis and utilizing a combination of applications and performance curves, this book starts off with a progressive foundation in satellite technology, and then moves on

  14. Digital-beamforming array antenna technologies for future ocean-observing satellite missions

    DEFF Research Database (Denmark)

    Iupikov, Oleg A.; Ivashina, Marianna V.; Cappellin, Cecilia

    2016-01-01

    Existing passive microwave radiometers that are used for ocean observations are limited in spatial resolution and geographic coverage, due to the limitations of traditional antenna technologies using mechanically-scanning reflectors and horn-type feeds. Future ocean observation missions call...... for new solutions, such as digitally-beamforming array feeds (DBAFs) as well as stationary and more complex reflectors. Our studies demonstrate that DBAFs can overcome the physically fundamental limitations of traditional horn feeds, and are capable of meeting all the challenging requirements for the next...

  15. Mobile satellite communications handbook

    CERN Document Server

    Cochetti, Roger

    2014-01-01

    With a Preface by noted satellite scientist Dr. Ahmad Ghais, the Second Edition reflects the expanded user base for this technology by updating information on historic, current, and planned commercial and military satellite systems and by expanding sections that explain the technology for non-technical professionals.   The book begins with an introduction to satellite communications and goes on to provide an overview of the technologies involved in mobile satellite communications, providing basic introductions to RF Issues, power Issues, link issues and system issues. It describes

  16. TESTING THE ASTEROSEISMIC MASS SCALE USING METAL-POOR STARS CHARACTERIZED WITH APOGEE AND KEPLER

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, Courtney R.; Johnson, Jennifer A.; Tayar, Jamie; Pinsonneault, Marc [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Elsworth, Yvonne P.; Chaplin, William J. [School of Physics and Astronomy, University of Birmingham, Edgbaston Park Road, West Midlands, Birmingham B15 2TT (United Kingdom); Shetrone, Matthew [McDonald Observatory, The University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712-0259 (United States); Mosser, Benoît [LESIA, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, Observatoire de Paris, F-92195 Meudon Cedex (France); Hekker, Saskia [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Harding, Paul [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106-7215 (United States); Silva Aguirre, Víctor [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Basu, Sarbani [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719, USA and JINA: Joint Institute for Nuclear Astrophysics (United States); Bizyaev, Dmitry [Apache Point Observatory, Sunspot, NM 88349 (United States); Bedding, Timothy R. [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Frinchaboy, Peter M. [Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); García, Rafael A. [Laboratoire AIM, CEA/DSM-CNRS, Universit Paris 7 Diderot, IRFU/SAp, Centre de Saclay, F-91191, Gif-sur-Yvette (France); Pérez, Ana E. García; Hearty, Fred R., E-mail: epstein@astronomy.ohio-state.edu [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); and others

    2014-04-20

    Fundamental stellar properties, such as mass, radius, and age, can be inferred using asteroseismology. Cool stars with convective envelopes have turbulent motions that can stochastically drive and damp pulsations. The properties of the oscillation frequency power spectrum can be tied to mass and radius through solar-scaled asteroseismic relations. Stellar properties derived using these scaling relations need verification over a range of metallicities. Because the age and mass of halo stars are well-constrained by astrophysical priors, they provide an independent, empirical check on asteroseismic mass estimates in the low-metallicity regime. We identify nine metal-poor red giants (including six stars that are kinematically associated with the halo) from a sample observed by both the Kepler space telescope and the Sloan Digital Sky Survey-III APOGEE spectroscopic survey. We compare masses inferred using asteroseismology to those expected for halo and thick-disk stars. Although our sample is small, standard scaling relations, combined with asteroseismic parameters from the APOKASC Catalog, produce masses that are systematically higher (<ΔM > =0.17 ± 0.05 M {sub ☉}) than astrophysical expectations. The magnitude of the mass discrepancy is reduced by known theoretical corrections to the measured large frequency separation scaling relationship. Using alternative methods for measuring asteroseismic parameters induces systematic shifts at the 0.04 M {sub ☉} level. We also compare published asteroseismic analyses with scaling relationship masses to examine the impact of using the frequency of maximum power as a constraint. Upcoming APOKASC observations will provide a larger sample of ∼100 metal-poor stars, important for detailed asteroseismic characterization of Galactic stellar populations.

  17. A research feasibility study proposal for conducting experimental research in curriculum sharing via Communications Technology Satellite among institutions having large minority enrollments

    Science.gov (United States)

    Williams, L., Jr.

    1978-01-01

    The applicability of the tele-conference method of curriculum sharing as well as the sharing of scientific research results between universities and industrial organizations was evaluated in relation to other techniques and methods. Ten universities cooperated with NC A&T State University in an effort to increase the number of minority scientists and engineers in the USA via the utilization of the communication features of satellites. Research activities, experiments and studies in curriculum sharing are described as well as the techniques, interconnections and equipment utilized. Suggested methods and recommendations for a continuation of innovative applications of satellite technology in higher education at NC A&T State University are included.

  18. The Impact of New Trends in Satellite Launches on Orbital Debris Environment

    Science.gov (United States)

    Karacalioglu, Arif Goktug; Stupl, Jan

    2016-01-01

    The main goal of this study is to examine the impact of new trends in satellite launch activities on the orbital debris environment and collision risk. Starting from the launch of the first artificial satellite in 1957, space borne technology has become an indispensable part of our lives. More than 6,000 satellites have been launched into Earth orbit. Though the annual number of satellites launched stayed flat for many decades, the trend has recently changed. The satellite market has been undergoing a major evolution with new space companies replacing the traditional approach of deploying a few large, complex and costly satellites with an approach to use a multitude of smaller, less complex and cheaper satellites. This new approach creates a sharp increase in the number of satellites and so the historic trends are no longer representative. As a foundation for this study, a scenario for satellite deployments based on the publicly announced future satellite missions has been developed. These constellation-deploying companies include, but are not limited to, Blacksky, CICERO, EROS, Landmapper, Leosat, Northstar, O3b, OmniEarth, OneWeb, Orbcomm, OuterNet, PlanetIQ, Planet Labs, Radarsat, RapidEye Next Generation, Sentinel, Skybox, SpaceX, and Spire. Information such as the annual number of launches, the number of orbital planes to be used by the constellation, as well as apogee, perigee, inclination, spacecraft mass and area were included or approximated. Besides the production of satellites, a widespread ongoing effort to enhance orbital injection capabilities will allow delivery of more spacecraft more accurately into Earth orbits. A long list of companies such as Microcosm, Rocket Lab, Firefly Space Systems, Sierra Nevada Corporation and Arca Space Corporation are developing new launch vehicles dedicated for small satellites. There are other projects which intend to develop interstages with propulsive capabilities which will allow the deployment of satellites into

  19. CHINA LAUNCHES NEW SCIENTIFIC SATELLITE

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    China on Sept. 27, 2004 launched a scientific satellite atop a Long March 2D carrier rocket from Jiuquan Satellite Launch Center in Gansu province. 10 minutes after the launch, the satellite entered a preset orbit and is running sound at the orbit. It is the 20th recoverable satellite for scientific and technological

  20. CHEMICAL ABUNDANCES IN FIELD RED GIANTS FROM HIGH-RESOLUTION H-BAND SPECTRA USING THE APOGEE SPECTRAL LINELIST

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Verne V.; Cunha, Katia [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States); Shetrone, Matthew D. [Department of Astronomy and McDonald Observatory, University of Texas, Austin, TX 78712 (United States); Meszaros, Szabolcs; Allende Prieto, Carlos [Instituto d' Astrofisica de Canarias, E-38205, La Laguna, Tenerife (Spain); Bizyaev, Dmitry [Apache Point Observatory, Sunspot, NM 88349 (United States); Garcia Perez, Ana; Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Schiavon, Ricardo [Astrophysics Research Institute, Liverpool John Moores University, Liverpool L3 5UX (United Kingdom); Holtzman, Jon [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); Johnson, Jennifer A., E-mail: vsmith@noao.edu [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

    2013-03-01

    High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory Fourier transform spectrometer, are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the Sloan Digital Sky Survey III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar populations. The red giant sample studied here was chosen to probe which chemical elements can be derived reliably from the H-band APOGEE spectral region. These red giants consist of two K-giants ({alpha} Boo and {mu} Leo), two M-giants ({beta} And and {delta} Oph), and one thermally pulsing asymptotic giant branch (TP-AGB) star of spectral type MS (HD 199799). Measured chemical abundances include the cosmochemically important isotopes {sup 12}C, {sup 13}C, {sup 14}N, and {sup 16}O, along with Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. The K and M giants exhibit the abundance signature of the first dredge-up of CN-cycle material, while the TP-AGB star shows clear evidence of the addition of {sup 12}C synthesized during {sup 4}He-burning thermal pulses and subsequent third dredge-up. A comparison of the abundances derived here with published values for these stars reveals consistent results to {approx}0.1 dex. The APOGEE spectral region and linelist is thus well suited for probing both Galactic chemical evolution, as well as internal nucleosynthesis and mixing in populations of red giants via high-resolution spectroscopy.

  1. Meteorological satellite systems

    CERN Document Server

    Tan, Su-Yin

    2014-01-01

    “Meteorological Satellite Systems” is a primer on weather satellites and their Earth applications. This book reviews historic developments and recent technological advancements in GEO and polar orbiting meteorological satellites. It explores the evolution of these remote sensing technologies and their capabilities to monitor short- and long-term changes in weather patterns in response to climate change. Satellites developed by various countries, such as U.S. meteorological satellites, EUMETSAT, and Russian, Chinese, Japanese and Indian satellite platforms are reviewed. This book also discusses international efforts to coordinate meteorological remote sensing data collection and sharing. This title provides a ready and quick reference for information about meteorological satellites. It serves as a useful tool for a broad audience that includes students, academics, private consultants, engineers, scientists, and teachers.

  2. Chemical Cartography in the Milky Way with SDSS/APOGEE: Multi-element abundances and abundance ratio variations

    Science.gov (United States)

    Holtzman, Jon A.; Hasselquist, Sten; Johnson, Jennifer; Bird, Jonathan C.; Majewski, Steven R.; SDSS/APOGEE Team

    2017-01-01

    The SDSS/APOGEE project is measuring abundances of multiple elements for several hundred thousand stars across the Milky Way. These allow the mapping of abundances and abundance ratio variations. Results will be presented for multiple abundance ratios across of the Galactic disk. The interpretation of mean abundance maps is complicated by variations in star formation history across the disk and by changing abundance ratios that result from an overall metallicity gradient. Variations in chemical abundance sequences, however, show the potential for using abundance ratios to track the movement of stars through the disk, and provide key information for constraining Galaxy formation and chemical evolution models.

  3. Land Mobile Satellite Service (LMSS): A conceptual system design and identification of the critical technologies: Part 2: Technical report

    Science.gov (United States)

    Naderi, F. (Editor)

    1982-01-01

    A conceptual system design for a satellite-aided land mobile service is described. A geostationary satellite which employs a large (55-m) UHF reflector to communicate with small inexpensive user antennas on mobile vehicles is discussed. It is shown that such a satellite system through multiple beam antennas and frequency reuse can provide thousands of radiotelephone and dispatch channels serving hundreds of thousands of users throughout the U.S.

  4. Technology Status and Developing Trends of Satellite Phased Array%星载相控阵天线的技术现状及发展趋势

    Institute of Scientific and Technical Information of China (English)

    阎鲁滨

    2012-01-01

    星载相控阵天线采用现代微波集成技术,在有限的卫星平台空间条件下,实现独立控制的多个点波束,满足未来通信的需求。相控阵天线可以实现波束间通信容量的调整,还可以根据需要改变波束形状,使用自适应调零的抗干扰技术,这些技术已在国外星上设备中广泛采用,具有广阔的发展前景。文章介绍了星载相控阵天线的研究现状、关键技术,以及发展趋势,并对我国星载相控阵天线技术的发展提出了建议。%Satellite phased array with modern microwave integrated circuit technology takes limit space on satellite and is able to independently control many beams to satisfy the demands ofmod- ern communication. The power ration between beams of phased array is adjustble. The radiation beam shape is variable and adaptive anti-jamming technology is easy to apply. Satellite phased ar- ray has been applied in wide domain and has increasing developing future. This paper gives the research status of satellite phased array, the key technologies and prospects the developing trends of satellite phased array.

  5. Key technologies of thermal test for DFH-4 platform satellite%东四平台卫星热试验中的关键技术

    Institute of Scientific and Technical Information of China (English)

    袁伟峰; 郄殿福; 许忠旭

    2014-01-01

    东四平台系列卫星对真空热试验期间的星上转发器在轨工作状态模拟、星表高/低热流模拟、星体吊装与水平支撑和污染控制等提出了较高要求。文章对微波负载能量耗散试验技术、红外灯阵设计、液氮冷板设计、卫星吊装与支撑技术、污染控制及星内真空度监测技术等在该系列卫星热试验中的成功应用与完善进行了分析、总结。%In the thermal test for the DFH-4 platform satellite, high technical requirements have to be met for the on-orbit operating state simulation of the transponder, the high or low heat flux simulation for satellite’s surfaces, the satellite lifting and horizontal bracing, and the pollution control. This paper analyses the technologies for the energy dissipation of the microwave load, the design of the infrared lamp array, the design of the cold plate with liquid nitrogen, the satellite lifting and horizontal bracing, the vacuum degree monitoring inside the satellite and the contamination control, as well as the applications of above-mentioned technologies in test.

  6. Galactic archaeology with asteroseismology and spectroscopy: Red giants observed by CoRoT and APOGEE

    Science.gov (United States)

    Anders, F.; Chiappini, C.; Rodrigues, T. S.; Miglio, A.; Montalbán, J.; Mosser, B.; Girardi, L.; Valentini, M.; Noels, A.; Morel, T.; Johnson, J. A.; Schultheis, M.; Baudin, F.; de Assis Peralta, R.; Hekker, S.; Themeßl, N.; Kallinger, T.; García, R. A.; Mathur, S.; Baglin, A.; Santiago, B. X.; Martig, M.; Minchev, I.; Steinmetz, M.; da Costa, L. N.; Maia, M. A. G.; Allende Prieto, C.; Cunha, K.; Beers, T. C.; Epstein, C.; García Pérez, A. E.; García-Hernández, D. A.; Harding, P.; Holtzman, J.; Majewski, S. R.; Mészáros, Sz.; Nidever, D.; Pan, K.; Pinsonneault, M.; Schiavon, R. P.; Schneider, D. P.; Shetrone, M. D.; Stassun, K.; Zamora, O.; Zasowski, G.

    2017-01-01

    With the advent of the space missions CoRoT and Kepler, it has recently become feasible to determine precise asteroseismic masses and relative ages for large samples of red giant stars. We present the CoRoGEE dataset, obtained from CoRoT light curves for 606 red giants in two fields of the Galactic disc that have been co-observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE). We used the Bayesian parameter estimation code PARAM to calculate distances, extinctions, masses, and ages for these stars in a homogeneous analysis, resulting in relative statistical uncertainties of ≲2% in distance, 4% in radius, 9% in mass and 25% in age. We also assessed systematic age uncertainties stemming from different input physics and mass loss. We discuss the correlation between ages and chemical abundance patterns of field stars over a broad radial range of the Milky Way disc (5 kpc

  7. Young [$\\alpha$/Fe]-enhanced stars discovered by CoRoT and APOGEE: What is their origin?

    CERN Document Server

    Chiappini, C; Rodrigues, T S; Miglio, A; Montalban, J; Mosser, B; Girardi, L; Valentini, M; Noels, A; Morel, T; Minchev, I; Steinmetz, M; Santiago, B X; Schultheis, M; Martig, M; da Costa, L N; Maia, M A G; Prieto, C Allende; Peralta, R de Assis; Hekker, S; Themeßl, N; Kallinger, T; Garcia, R A; Mathur, S; Baudin, F; Beers, T C; Cunha, K; Harding, P; Holtzman, J; Majewski, S; Meszaros, Sz; Nidever, D; Pan, K; Schiavon, R P; Shetrone, M D; Schneider, D P; Stassun, K

    2015-01-01

    We report the discovery of a group of apparently young CoRoT red-giant stars exhibiting enhanced [alpha/Fe] abundance ratios (as determined from APOGEE spectra) with respect to Solar values. Their existence is not explained by standard chemical evolution models of the Milky Way, and shows that the chemical-enrichment history of the Galactic disc is more complex. We find similar stars in previously published samples for which isochrone-ages could be robustly obtained, although in smaller relative numbers, which could explain why these stars have not received prior attention. The young [alpha/Fe]-rich stars are much more numerous in the CoRoT-APOGEE (CoRoGEE) inner-field sample than in any other high-resolution sample available at present, as only CoRoGEE can explore the inner-disc regions and provide ages for its field stars. The kinematic properties of the young [$\\alpha$/Fe]-rich stars are not clearly thick-disc like, despite their rather large distances from the Galactic mid-plane. Our tentative interpretat...

  8. Evidence of AGB pollution in Galactic globular clusters from the Mg-Al anticorrelations observed by the APOGEE survey

    CERN Document Server

    Ventura, P; Dell'Agli, F; D'Antona, F; Meszaros, Sz; Lucatello, S; Di Criscienzo, M; Shetrone, M; Tailo, M; Tang, Baitian; Zamora, O

    2016-01-01

    We study the formation of multiple populations in globular clusters (GC), under the hypothesis that stars in the second generation formed from the winds of intermediate-mass stars, ejected during the asymptotic giant branch (AGB) phase, possibly diluted with pristine gas, sharing the same chemical composition of first-generation stars. To this aim, we use the recent APOGEE data, which provide the surface chemistry of a large sample of giant stars, belonging to clusters that span a wide metallicity range. The APOGEE data set is particularly suitable to discriminate among the various pollution scenarios proposed so far, as it provides the surface abundances of Mg and Al, the two elements involved in a nuclear channel extremely sensitive to the temperature, hence to the metallicity of the polluters. The present analysis shows a remarkable agreement between the observations and the theoretical yields from massive AGB stars. In particular, the observed extension of the depletion of Mg and O and the increase in Al ...

  9. Chemical Abundances in Field Red Giants from High-Resolution H-Band Spectra using the APOGEE Spectral Linelist

    CERN Document Server

    Smith, Verne V; Shetrone, Matthew D; Meszaros, Szabolcs; Prieto, Carlos Allende; Bizyaev, Dmitry; Perez, Ana Garcia; Majewski, Steven R; Schiavon, Ricardo; Holtzman, Jon; Johnson, Jennifer A

    2012-01-01

    High-resolution H-band spectra of five bright field K, M, and MS giants, obtained from the archives of the Kitt Peak National Observatory (KPNO) Fourier Transform Spectrometer (FTS), are analyzed to determine chemical abundances of 16 elements. The abundances were derived via spectrum synthesis using the detailed linelist prepared for the SDSS III Apache Point Galactic Evolution Experiment (APOGEE), which is a high-resolution near-infrared spectroscopic survey to derive detailed chemical abundance distributions and precise radial velocities for 100,000 red giants sampling all Galactic stellar populations. Measured chemical abundances include the cosmochemically important isotopes 12C, 13C, 14N, and 16O, along with Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. A comparison of the abundances derived here with published values for these stars reveals consistent results to ~0.1 dex. The APOGEE spectral region and linelist is, thus, well-suited for probing both Galactic chemical evolution, as well as inter...

  10. Evidence of AGB Pollution in Galactic Globular Clusters from the Mg-Al Anticorrelations Observed by the APOGEE Survey

    Science.gov (United States)

    Ventura, P.; García-Hernández, D. A.; Dell'Agli, F.; D'Antona, F.; Mészáros, Sz.; Lucatello, S.; Di Criscienzo, M.; Shetrone, M.; Tailo, M.; Tang, Baitian; Zamora, O.

    2016-11-01

    We study the formation of multiple populations in globular clusters (GCs), under the hypothesis that stars in the second generation formed from the winds of intermediate-mass stars, ejected during the asymptotic giant branch (AGB) phase, possibly diluted with pristine gas, sharing the same chemical composition of first-generation stars. To this aim, we use the recent Apache Point Observatory Galactic Evolution Experiment (APOGEE) data, which provide the surface chemistry of a large sample of giant stars, belonging to clusters that span a wide metallicity range. The APOGEE data set is particularly suitable to discriminate among the various pollution scenarios proposed so far, as it provides the surface abundances of Mg and Al, the two elements involved in a nuclear channel extremely sensitive to the temperature, hence to the metallicity of the polluters. The present analysis shows a remarkable agreement between the observations and the theoretical yields from massive AGB stars. In particular, the observed extension of the depletion of Mg and O and the increase in Al is well reproduced by the models and the trend with the metallicity is also fully accounted for. This study further supports the idea that AGB stars were the key players in the pollution of the intra-cluster medium, from which additional generations of stars formed in GCs.

  11. A Precise Determination of the Mid-Infrared Interstellar Extinction Law Based on the APOGEE Spectroscopic Survey

    CERN Document Server

    Xue, Mengyao; Gao, Jian; Liu, Jiaming; Wang, Shu; Li, Aigen

    2016-01-01

    A precise measure of the mid-infrared interstellar extinction law is crucial to the investigation of the properties of interstellar dust, especially of the grains in the large size end. Based on the stellar parameters derived from the SDSS-III/APOGEE spectroscopic survey, we select a large sample of G- and K-type giants as the tracers of the Galactic mid-infrared extinction. We calculate the intrinsic stellar color excesses from the stellar effective temperatures and use them to determine the mid-infrared extinction for a given line of sight. For the entire sky of the Milky Way surveyed by APOGEE, we derive the extinction (relative to the K$_{\\rm S}$ band at wavelength $\\lambda=2.16\\mu$m) for the four \\emph{WISE} bands at 3.4, 4.6, 12 and 22$\\mu$m, the four \\emph{Spitzer}/IRAC bands at 3.6, 4.5, 5.8 and 8$\\mu$m, the \\emph{Spitzer}/MIPS24 band at 23.7$\\mu$m and for the first time, the \\emph{AKARI}/S9W band at 8.23$\\mu$m. Our results agree with previous works in that the extinction curve is flat in the ~3--8$\\m...

  12. The Communications Satellite as Educational Tool.

    Science.gov (United States)

    Long, Peter

    1982-01-01

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

  13. Satellite Remote Sensing Image Analysis Technology Based on eCognition%基于eCognition的卫星遥感影像分析技术

    Institute of Scientific and Technical Information of China (English)

    孙悦

    2014-01-01

    The satellite remote sensing image analysis is a research hotspot in recent years. In this paper,the current progress of information extraction technology on satellite sensing images is analyzed,the advantage of object-oriented high-resolution image analysis is highlighted,and the application of target change detection of satellite sensing images in military field is introduced. In this paper,the object-oriented multiscale segmentation strategy is used in the field of satellite remote sensing image processing,and secondary develop-ment processes is implemented based on eCognition SDK. The results of multiple experiments show that the proposed satellite remote sensing image analysis technology can implement better information extraction and analysis.%卫星遥感影像分析技术是近年来的一个研究热点问题。归纳总结了遥感影像信息提取技术的发展现状,阐述了面向对象的高分辨率遥感影像分析技术的优势,介绍了遥感影像目标变化检测技术的应用情况。将面向对象的多尺度分割策略应用在卫星遥感影像处理领域,实现了基于eCognition SDK的二次开发流程,取得了良好的实验效果。

  14. DFH Satellite Co.,Ltd.

    Institute of Scientific and Technical Information of China (English)

    SunQing

    2004-01-01

    DFH Satellite Co.,Ltd. is a hi-tech enterprise founded and sponsored by China Aerospace Science and Technology Corporation(CASC) and one of CASC subsidiaries,China Academy of Space Technology (CAST). The company is mainly engaged in the research and development of small satellites and micro-satellites, Osystem designs and product development for satellite application projects as well as the international exchanges and cooperation.

  15. Applications Technology Satellite 6 - Upgrading the life style of millions of people. [health and educational TV broadcasting

    Science.gov (United States)

    Thole, J. M.; Dornbrand, H.

    1974-01-01

    The primary objective of the ATS-6 is to demonstrate the feasibility of operating a high-powered geosynchronous communications satellite capable of relaying color TV and other high-quality signals on multiple frequencies to relatively simple and inexpensive ground receivers. Other capabilities include providing a link between ships, aircraft, or other earth satellites (e.g., low-orbit meteorological satellites) and the ground. The ATS-6 flight-objective accomplishments and subsystem performance for its first 30 days in orbit are summarized. Success is predicted for most of the experiments carried.

  16. Multidisciplinary studies of the social, economic and political impact resulting from recent advances in satellite meteorology. Volume 6: Executive summary. [technological forecasting spacecraft control/attitude (inclination) -classical mechanics

    Science.gov (United States)

    1975-01-01

    An assessment of the technological impact of modern satellite weather forecasting for the United States is presented. Topics discussed are: (1) television broadcasting of weather; (2) agriculture (crop production); (3) water resources; (4) urban development; (5) recreation; and (6) transportation.

  17. Study the Space Debris Impact in the Early Stages of the Nano-Satellite Design

    Science.gov (United States)

    Mahdi, Mohammed Chessab

    2016-12-01

    The probability of KufaSat collisions with different sizes of orbital debris and with other satellites which operating in the same orbit during orbital lifetime was determined. Apogee/Perigee Altitude History was used to graph apogee and perigee altitudes over KufaSat lifetime. The required change in velocity for maneuvers necessary to reentry atmospheric within 25 years was calculated. The prediction of orbital lifetime of KufaSat using orbital parameters and engineering specifications as inputs to the Debris Assessment Software (DAS) was done, it has been verified that the orbital lifetime will not be more than 25 years after end of mission which is compatible with recommendation of Inter-Agency Space Debris Coordination Committee (IADC).

  18. The APOGEE red-clump catalog: Precise distances, velocities, and high-resolution elemental abundances over a large area of the Milky Way's disk

    CERN Document Server

    Bovy, Jo; Rix, Hans-Walter; Girardi, Léo; Zasowski, Gail; Chojnowski, S Drew; Holtzman, Jon; Epstein, Courtney; Frinchaboy, Peter M; Hayden, Michael R; Rodrigues, Thaíse S; Majewski, Steven R; Johnson, Jennifer A; Pinsonneault, Marc H; Stello, Dennis; Prieto, Carlos Allende; Andrews, Brett; Basu, Sarbani; Beers, Timothy C; Bizyaev, Dmitry; Burton, Adam; Chaplin, William J; Cunha, Katia; Elsworth, Yvonne; García, Rafael A; García-Herńandez, Domingo A; Pérez, Ana E García; Hearty, Fred R; Hekker, Saskia; Kallinger, Thomas; Kinemuchi, Karen; Koesterke, Lars; Mészáros, Szabolcs; Mosser, Benoît; O'Connell, Robert W; Oravetz, Daniel; Pan, Kaike; Robin, Annie C; Schiavon, Ricardo P; Schneider, Donald P; Schultheis, Mathias; Serenelli, Aldo; Shetrone, Matthew; Aguirre, Victor Silva; Simmons, Audrey; Skrutskie, Michael; Smith, Verne V; Stassun, Keivan; Weinberg, David H; Wilson, John C; Zamora, Olga

    2014-01-01

    The Sloan Digital Sky Survey III's Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution near-infrared spectroscopic survey covering all of the major components of the Galaxy, including the dust-obscured regions of the inner Milky Way disk and bulge. Here we present a sample of 10,352 likely red-clump stars (RC) from the first two years of APOGEE operations, selected based on their position in color-metallicity-surface-gravity-effective-temperature space using a new method calibrated using stellar-evolution models and high-quality asteroseismology data. The narrowness of the RC locus in color-metallicity-luminosity space allows us to assign distances to the stars with an accuracy of 5 to 10%. The sample extends to typical distances of about 3 kpc from the Sun, with some stars out to 8 kpc, and spans a volume of approximately 100 kpc^3 over 5 kpc <~ R <~ 14 kpc, |Z| <~ 2 kpc, and -15 deg <~ Galactocentric azimuth <~ 30 deg. The APOGEE red-clump (APOGEE-RC) catalog ...

  19. Study of time-lapse processing for dynamic hydrologic conditions. [electronic satellite image analysis console for Earth Resources Technology Satellites imagery

    Science.gov (United States)

    Serebreny, S. M.; Evans, W. E.; Wiegman, E. J.

    1974-01-01

    The usefulness of dynamic display techniques in exploiting the repetitive nature of ERTS imagery was investigated. A specially designed Electronic Satellite Image Analysis Console (ESIAC) was developed and employed to process data for seven ERTS principal investigators studying dynamic hydrological conditions for diverse applications. These applications include measurement of snowfield extent and sediment plumes from estuary discharge, Playa Lake inventory, and monitoring of phreatophyte and other vegetation changes. The ESIAC provides facilities for storing registered image sequences in a magnetic video disc memory for subsequent recall, enhancement, and animated display in monochrome or color. The most unique feature of the system is the capability to time lapse the imagery and analytic displays of the imagery. Data products included quantitative measurements of distances and areas, binary thematic maps based on monospectral or multispectral decisions, radiance profiles, and movie loops. Applications of animation for uses other than creating time-lapse sequences are identified. Input to the ESIAC can be either digital or via photographic transparencies.

  20. The apogee red-clump catalog: Precise distances, velocities, and high-resolution elemental abundances over a large area of the Milky Way's disk

    Energy Technology Data Exchange (ETDEWEB)

    Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Nidever, David L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Rix, Hans-Walter [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany); Girardi, Léo; Rodrigues, Thaíse S. [Osservatorio Astronomico di Padova-INAF, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Zasowski, Gail [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Chojnowski, S. Drew; Majewski, Steven R. [Department of Astronomy, University of Virginia, Charlottesville, VA, 22904 (United States); Holtzman, Jon; Hayden, Michael R. [New Mexico State University, Las Cruces, NM 88003 (United States); Epstein, Courtney; Johnson, Jennifer A.; Pinsonneault, Marc H.; Andrews, Brett [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Frinchaboy, Peter M. [Department of Physics and Astronomy, Texas Christian University, Fort Worth, TX 76129 (United States); Stello, Dennis [Sydney Institute for Astronomy (SIfA), School of Physics, University of Sydney, NSW 2006 (Australia); Allende Prieto, Carlos [Instituto de Astrofísica de Canarias (IAC), E-38200 La Laguna, Tenerife (Spain); Basu, Sarbani [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Beers, Timothy C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Bizyaev, Dmitry, E-mail: bovy@ias.edu [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); and others

    2014-08-01

    The Sloan Digital Sky Survey III's Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a high-resolution near-infrared spectroscopic survey covering all of the major components of the Galaxy, including the dust-obscured regions of the inner Milky Way disk and bulge. Here we present a sample of 10,341 likely red-clump stars (RC) from the first two years of APOGEE operations, selected based on their position in color-metallicity-surface-gravity-effective-temperature space using a new method calibrated using stellar evolution models and high-quality asteroseismology data. The narrowness of the RC locus in color-metallicity-luminosity space allows us to assign distances to the stars with an accuracy of 5%-10%. The sample extends to typical distances of about 3 kpc from the Sun, with some stars out to 8 kpc, and spans a volume of approximately 100 kpc{sup 3} over 5 kpc ≲ R ≲ 14 kpc, |Z| ≲ 2 kpc, and –15° ≲ Galactocentric azimuth ≲ 30°. The APOGEE red-clump (APOGEE-RC) catalog contains photometry from the Two Micron All Sky Survey, reddening estimates, distances, line-of-sight velocities, stellar parameters and elemental abundances determined from the high-resolution APOGEE spectra, and matches to major proper motion catalogs. We determine the survey selection function for this data set and discuss how the RC selection samples the underlying stellar populations. We use this sample to limit any azimuthal variations in the median metallicity within the ≈45° azimuthal region covered by the current sample to be ≤0.02 dex, which is more than an order of magnitude smaller than the radial metallicity gradient. This result constrains coherent non-axisymmetric flows within a few kiloparsecs from the Sun.

  1. Chemical tagging in the SDSS-III/APOGEE survey: new identifications of halo stars with globular cluster origins

    CERN Document Server

    Martell, Sarah; Lucatello, Sara; Schiavon, Ricardo; Meszaros, Szabolcs; Prieto, Carlos Allende; Hernandez, Anibal Garcia; Beers, Tim; Nidever, David

    2016-01-01

    We present new identifications of five red giant stars in the Galactic halo with chemical abundance patterns that indicate they originally formed in globular clusters. Using data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE) Survey available through Sloan Digital Sky Survey Data Release 12 (DR12), we first identify likely halo giants, and then search those for the well-known chemical tags associated with globular clusters, specifically enrichment in nitrogen and aluminum. We find that 2% of the halo giants in our sample have this chemical signature, in agreement with previous results. Following the interpretation in our previous work on this topic, this would imply that at least 13% of halo stars originally formed in globular clusters. Recent developments in the theoretical understanding of globular cluster formation raise questions about that interpretation, and we concede the possibility that these migrants represent a small fraction of the halo field. There are roughly as many st...

  2. Satellite Communication.

    Science.gov (United States)

    Technology Teacher, 1985

    1985-01-01

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

  3. Trends In Satellite Communication

    Science.gov (United States)

    Poley, William A.; Stevens, Grady H.; Stevenson, Steven M.; Lekan, Jack; Arth, Clifford H.; Hollansworth, James E.; Miller, Edward F.

    1988-01-01

    Report assesses trends in satellite communication from present to year 2010. Examines restrictions imposed by limited spectrum resource and technology needs created by trends. Personal communications, orbiting switchboards, and videophones foreseen.

  4. Extinction maps toward the Milky Way bulge: Two-dimensional and three-dimensional tests with apogee

    Energy Technology Data Exchange (ETDEWEB)

    Schultheis, M. [Université de Nice Sophia-Antipolis, CNRS, Observatoire de Côte d' Azur, Laboratoire Lagrange, 06304 Nice Cedex 4 (France); Zasowski, G. [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Allende Prieto, C. [Instituto de Astrofísica de Canarias, Calle Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Anders, F.; Chiappini, C. [Leibniz-Institut für Astrophysik Potsdam (AIP), D-14482 Potsdam (Germany); Beaton, R. L.; García Pérez, A. E.; Majewski, S. R. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Beers, T. C. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Bizyaev, D. [Apache Point Observatory, Sunspot, NM 88349 (United States); Frinchaboy, P. M. [Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); Ge, J. [Astronomy Department, University of Florida, Gainesville, FL 32611 (United States); Hearty, F.; Schneider, D. P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Holtzman, J. [New Mexico State University, Las Cruces, NM 88003 (United States); Muna, D. [Department of Astronomy, The Ohio State University, Columbus, OH 43210 (United States); Nidever, D. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Shetrone, M., E-mail: mathias.schultheis@oca.eu, E-mail: gail.zasowski@gmail.com [McDonald Observatory, The University of Texas at Austin, Austin, TX 78712 (United States)

    2014-07-01

    Galactic interstellar extinction maps are powerful and necessary tools for Milky Way structure and stellar population analyses, particularly toward the heavily reddened bulge and in the midplane. However, due to the difficulty of obtaining reliable extinction measures and distances for a large number of stars that are independent of these maps, tests of their accuracy and systematics have been limited. Our goal is to assess a variety of photometric stellar extinction estimates, including both two-dimensional and three-dimensional extinction maps, using independent extinction measures based on a large spectroscopic sample of stars toward the Milky Way bulge. We employ stellar atmospheric parameters derived from high-resolution H-band Apache Point Observatory Galactic Evolution Experiment (APOGEE) spectra, combined with theoretical stellar isochrones, to calculate line-of-sight extinction and distances for a sample of more than 2400 giants toward the Milky Way bulge. We compare these extinction values to those predicted by individual near-IR and near+mid-IR stellar colors, two-dimensional bulge extinction maps, and three-dimensional extinction maps. The long baseline, near+mid-IR stellar colors are, on average, the most accurate predictors of the APOGEE extinction estimates, and the two-dimensional and three-dimensional extinction maps derived from different stellar populations along different sightlines show varying degrees of reliability. We present the results of all of the comparisons and discuss reasons for the observed discrepancies. We also demonstrate how the particular stellar atmospheric models adopted can have a strong impact on this type of analysis, and discuss related caveats.

  5. Business Use of Satellite Communications.

    Science.gov (United States)

    Edelson, Burton I.; Cooper, Robert S.

    1982-01-01

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

  6. Fast Development Of China's Small Satellite Industry

    Institute of Scientific and Technical Information of China (English)

    Sun Hongjin

    2009-01-01

    @@ China Spacesat Co., Ltd of China Academy of Space Technology (CAST) recently said, along with the successful launch of HJ-1A/B for the environment and disaster monitoring and forecasting small satellite constellation and after years of efforts, small satellite development technology has achieved fruitful results, and the development status has been greatly improved.China's small satellite technology has realized a great-leap-forward in development from a single satellite model to series model, from the satellite program to space industry. China has explored a development road for China's small satellite industrialization, and a modern small satellite development base has resulted.

  7. Comprehensive Study on Small and Low Cost Satellite Technology for Earth Observation with Case Study for Indonesia: Projection for 2002-2022

    Science.gov (United States)

    Djojodihardjo, Harijono

    and economic progress, while facing global competitiveness locally as opportunities and challenges. Of particular importance is the utilization and development of earth observation capabilities for environmental natural resources imperatives to this end is quite significant. On one hand there may appear challenges to achieve unique and high quality requirements on many of the elements of social and economic progress, i.e. natural resources, human resources, market opportunities and geographical advantage; on the other hand one may face constraints in the financial system, cultural inertia and paradigm, and the need to carry forward large momentum that may pull back technological and economic progress that may be characterized by a "roller coaster" dynamics. Satellite Technology for Earth Observation, its Utilization and Development is carried out with Indonesian Development Interest in mind. Space System Services and Players are identified. Mission objectives associated with Urban and Rural Areas as well as Satellite-Based Multimedia Technology Applications For Promoting Rural Development will be identified. System design analysis and synthesis will be elaborated and some alternatives will be presented following a unified system outlook. Ground Segment and Space Segment Architecture will be elaborated by carrying out Architecture Optimization.

  8. Hypermodular Distributed Solar Power Satellites -- Exploring a Technology Option for Near-Term LEO Demonstration and GLPO Full-Scale Plants

    CERN Document Server

    Leitgab, Martin

    2013-01-01

    This paper presents a new and innovative design for scaleable space solar power systems based on satellite self-assembly and microwave spatial power combination. Lower system cost of utility-scale space solar power is achieved by independence of yet-to-be-built in-space assembly and transportation infrastructure. Using current and expected near-term technology, this study explores a design for near-term space solar power low-Earth orbit demonstrators and for mid-term utility-scale power plants in geosynchronous Laplace plane orbits. High-level economic considerations in the context of current and expected future launch costs are given as well.

  9. Integrated Satellite-HAP Systems

    DEFF Research Database (Denmark)

    Cianca, Ernestina; De Sanctis, Mauro; De Luise, Aldo

    2005-01-01

    for an efficient hybrid terrestrial-satellite communication system. Two integrated HAP-satellite scenarios are presented, in which the HAP is used to overcome some of the shortcomings of satellite- based communications. Moreover, it is shown that the integration of HAPs with satellite systems can be used......Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element...

  10. A statistical rain attenuation prediction model with application to the advanced communication technology satellite project. 3: A stochastic rain fade control algorithm for satellite link power via non linear Markow filtering theory

    Science.gov (United States)

    Manning, Robert M.

    1991-01-01

    The dynamic and composite nature of propagation impairments that are incurred on Earth-space communications links at frequencies in and above 30/20 GHz Ka band, i.e., rain attenuation, cloud and/or clear air scintillation, etc., combined with the need to counter such degradations after the small link margins have been exceeded, necessitate the use of dynamic statistical identification and prediction processing of the fading signal in order to optimally estimate and predict the levels of each of the deleterious attenuation components. Such requirements are being met in NASA's Advanced Communications Technology Satellite (ACTS) Project by the implementation of optimal processing schemes derived through the use of the Rain Attenuation Prediction Model and nonlinear Markov filtering theory.

  11. Review on Development and New Technologies of Military Satellite Communications Aboard%国外军事卫星通信发展及新技术综述

    Institute of Scientific and Technical Information of China (English)

    朱立东

    2016-01-01

    The military communication is one of the most important factors to determine the outcome of war.The side having infor⁃mation superiority is more active in the war.The military communication includes HF communication,VHF communication,meteor trail communication and satellite communication.The satellite communication has such advantages as wide coverage and large capacity,which can meet the requirements of information transmission in the battlefield in a better way. The military powers represented by the United States of America,Russia and West Europe possess advanced technologies of military satellite communication,have built some typical military satellite communication systems,and have applied them to information transmission in the battlefield,which help the operational commanding authority to make real⁃time decision in military countermeasures.To get the advantages of military countermeasures,these military powers continue developing new techniques,and remain in a dominant position in information countermeasures.On the basis of analyzing the development trend of military satellite communication,this paper introduces briefly some new technologies.%军事通信是决定战争胜负的重要因素,具有信息优势的一方更容易获得战争的主动权。军事通信包含短波通信、超短波通信、流星余迹通信、卫星通信等方式,其中卫星通信具有覆盖范围广、容量大等优点,能更好地满足战场信息传输需求。以美国、俄罗斯、西欧发达国家为代表的军事强国,拥有先进的军事卫星通信技术,建造了一些典型的军事卫星通信系统,并应用于战场信息传递,为指挥机关的实时决策提供依据。为了在军事对抗中保持优势,这些军事强国又不断发展新技术,在信息对抗中始终处于主导地位。在分析现有军事卫星通信发展动态的基础上,对适用于军事卫星通信的新技术进行了综述。

  12. 防震减灾中卫星遥感技术应用分析%Application of satellite remote sensing technology in earthquake disaster reduction

    Institute of Scientific and Technical Information of China (English)

    谢礼立; 张景发

    2000-01-01

    卫星遥感技术在减轻自然灾害中发挥了十分重要的作用,但也不得不指出,卫星遥感技术在防震减灾工作中,无论在国内或国外均尚未得到有效的应用.这一方面固然是由于地震事件十分复杂,地震孕育和发生的规律尚未搞清,难以发挥卫星遥感技术的作用,另一方面也由于可以使用的卫星遥感技术的分辨率还不够高,重复观察的周期长,限制了这一技术在防震减灾工作中的应用.有鉴于近年来卫星遥感技术有了新的进展,使其有可能在防震减灾中发挥特殊的作用,本文旨在对卫星遥感技术在防震减灾工作的应用,对它的可行性、有效性、经济性和与此相关的科学技术问题进行探讨,使这项技术能在防震减灾领域早日得到应用,以促进我国防震减灾工作的发展.%With the rapid development of satellite remote sensing technology,it has been widely applied in national economics and martial area,in particular,in the field of natural disaster reduction,for examples,in forecasting and controlling of flood,preventing of forest-fire,monitoring of landslide and debris flow and so on.Regretfully,as we understand the satellite remote sensing technology are rarely applied both at home and abroad for earthquake disaster reduction.It is because that on the one side,earthquake is a very complicated natural phenomenon with its indistinct genesis mechanism and occurrence of very low probability and on the other side,the resolution of satellite remote sensing image is too low and satellite repeat period is too long that constrain this technique to be used in earthquake disaster reduction.This paper intends to address the application,practicability and other relative scientific-technical and economic issues,of satellite remote sensing technology in reducing earthquake disaster,it is believed that the earlier use of satellite remote sensing technology in China will provide a more effective and economic

  13. Analysis on Autotracking Technology of LEO Satellite%低轨卫星自跟踪技术分析

    Institute of Scientific and Technical Information of China (English)

    姚勇

    2011-01-01

    针对低轨(LEO)卫星无信标信号时,传统自跟踪方式无法对其进行有效跟踪的问题,提出了全数字跟踪体制。对采用频分时分复合多址(FDMA/TDMA)体制的低轨卫星,采用宽带检测结合窄带跟踪的方法,快速准确地提取方位俯仰误差,实现了对目标卫星的高精度跟踪。对采用码分多址(CDMA)体制的低轨卫星,采用频域跟踪的方法,实现了低信噪比条件下对目标卫星的高精度跟踪。%The traditional autotracking method can't implement effective tracking for LEO satellite without beacon signal.To solve this problem,an all-digit tracking method is proposed in this paper.For the LEO satellite operating in FDMA/TDMA mode,this method combining narrowband tracking with wideband detection can quickly and accurately extract the errors of azimuth and elevation and fulfills the tracking with high precision.For the LEO satellite operating in CDMA mode,this algorithm extracting tracking error in frequency domain can precisely track the LEO satellite with low SNR signal of LEO.

  14. A Laboratory log(gf) Measurement of the Ti II 15873.84 {\\AA} H-band Line in Support of SDSS-III APOGEE

    CERN Document Server

    Wood, Michael P; Shetrone, Matthew D

    2014-01-01

    The SDSS-III APOGEE collaboration has identified a single useable line in the H-band spectra of APOGEE target stars arising from a singly ionized species. This line of Ti II (${\\lambda}_{air}$ = 15873.84 {\\AA}) is therefore of great importance for use in stellar surface gravity, or log(g), determinations via the Saha equation. While a theoretical estimate of the line strength exists, to date no laboratory measurement of the line strength has been reported. Herein we report an absolute laboratory transition probability measurement for this important Ti II line. A relative line strength measurement is made of the Ti II H-band line of interest and a reference line with a previously reported absolute transition probability. This ratio is measured using multiple spectra of a high-current water-cooled HC lamp recorded with a calibrated FT-IR spectrometer.

  15. Tracing chemical evolution over the extent of the Milky Way's disk with apogee red clump stars

    Energy Technology Data Exchange (ETDEWEB)

    Nidever, David L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48104 (United States); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Bird, Jonathan C. [Physics and Astronomy Department, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States); Andrews, Brett H.; Johnson, Jennifer A.; Weinberg, David H. [Department of Astronomy and the Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Hayden, Michael; Holtzman, Jon; Feuillet, Diane [New Mexico State University, Las Cruces, NM 88003 (United States); Majewski, Steven R.; García Pérez, Ana E. [Department of Astronomy, University of Virginia, Charlottesville, VA, 22904 (United States); Smith, Verne [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Robin, Annie C.; Sobeck, Jennifer [Institut Utinam, CNRS UMR 6213, OSU THETA, Université de Franche-Comté, 41bis avenue de l' Observatoire, F-25000 Besançon (France); Cunha, Katia [Observatorio Nacional, Rio de Janeiro (Brazil); Allende Prieto, Carlos [Instituto de Astrofsica de Canarias, E-38205 La Laguna, Tenerife (Spain); Zasowski, Gail [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Schiavon, Ricardo P. [Astrophysics Research Institute, IC2, Liverpool Science Park, Liverpool John Moores University, 146 Brownlow Hill, Liverpool, L3 5RF (United Kingdom); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Shetrone, Matthew, E-mail: dnidever@umich.edu [University of Texas at Austin, McDonald Observatory, 32 Fowlkes Road, McDonald Observatory, TX 79734-3005 (United States); and others

    2014-11-20

    We employ the first two years of data from the near-infrared, high-resolution SDSS-III/APOGEE spectroscopic survey to investigate the distribution of metallicity and α-element abundances of stars over a large part of the Milky Way disk. Using a sample of ≈10, 000 kinematically unbiased red-clump stars with ∼5% distance accuracy as tracers, the [α/Fe] versus [Fe/H] distribution of this sample exhibits a bimodality in [α/Fe] at intermediate metallicities, –0.9 < [Fe/H] <–0.2, but at higher metallicities ([Fe/H] ∼+0.2) the two sequences smoothly merge. We investigate the effects of the APOGEE selection function and volume filling fraction and find that these have little qualitative impact on the α-element abundance patterns. The described abundance pattern is found throughout the range 5 < R < 11 kpc and 0 < |Z| < 2 kpc across the Galaxy. The [α/Fe] trend of the high-α sequence is surprisingly constant throughout the Galaxy, with little variation from region to region (∼10%). Using simple galactic chemical evolution models, we derive an average star-formation efficiency (SFE) in the high-α sequence of ∼4.5 × 10{sup –10} yr{sup –1}, which is quite close to the nearly constant value found in molecular-gas-dominated regions of nearby spirals. This result suggests that the early evolution of the Milky Way disk was characterized by stars that shared a similar star-formation history and were formed in a well-mixed, turbulent, and molecular-dominated ISM with a gas consumption timescale (SFE{sup –1}) of ∼2 Gyr. Finally, while the two α-element sequences in the inner Galaxy can be explained by a single chemical evolutionary track, this cannot hold in the outer Galaxy, requiring, instead, a mix of two or more populations with distinct enrichment histories.

  16. The SDSS-III APOGEE radial velocity survey of M dwarfs. I. Description of the survey and science goals

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, R.; Bender, C. F.; Mahadevan, S.; Terrien, R. C.; Schneider, D. P.; Fleming, S. W. [Center for Exoplanets and Habitable Worlds, The Pennsylvania State University, University Park, PA 16802 (United States); Blake, C. H. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Carlberg, J. K. [Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015 (United States); Zasowski, G.; Hearty, F. [University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Crepp, J. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Rajpurohit, A. S.; Reylé, C. [Institut UTINAM, CNRS UMR 6213, Observatoire des Sciences de l' Univers THETA Franche-Comt é-Bourgogne, Université de Franche Comté, Observatoire de Besançon, BP 1615, F-25010 Besançon Cedex (France); Nidever, D. L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Prieto, C. Allende; Hernández, J. [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); Bizyaev, D. [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349-0059 (United States); Ebelke, G. [Department of Physics and Astronomy, Texas Christian University, TCU Box 298840, Fort Worth, TX 76129 (United States); Frinchaboy, P. M. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Ge, J. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States); and others

    2013-12-01

    We are carrying out a large ancillary program with the Sloan Digital Sky Survey, SDSS-III, using the fiber-fed multi-object near-infrared APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 1200 M dwarfs. These observations will be used to measure spectroscopic rotational velocities, radial velocities, physical stellar parameters, and variability of the target stars. Here, we describe the target selection for this survey, as well as results from the first year of scientific observations based on spectra that will be publicly available in the SDSS-III DR10 data release. As part of this paper we present radial velocities and rotational velocities of over 200 M dwarfs, with a vsin i precision of ∼2 km s{sup –1} and a measurement floor at vsin i = 4 km s{sup –1}. This survey significantly increases the number of M dwarfs studied for rotational velocities and radial velocity variability (at ∼100-200 m s{sup –1}), and will inform and advance the target selection for planned radial velocity and photometric searches for low-mass exoplanets around M dwarfs, such as the Habitable Zone Planet Finder, CARMENES, and TESS. Multiple epochs of radial velocity observations enable us to identify short period binaries, and adaptive optics imaging of a subset of stars enables the detection of possible stellar companions at larger separations. The high-resolution APOGEE spectra, covering the entire H band, provide the opportunity to measure physical stellar parameters such as effective temperatures and metallicities for many of these stars. At the culmination of this survey, we will have obtained multi-epoch spectra and radial velocities for over 1400 stars spanning the spectral range M0-L0, providing the largest set of near-infrared M dwarf spectra at high resolution, and more than doubling the number of known spectroscopic vsin i values for M dwarfs. Furthermore, by modeling telluric lines to correct for small instrumental radial velocity shifts, we

  17. China Launches First Ever Nano-satellite

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    China successfully launched two scientific satellites, including a nano-satellite for the first time, heralding a breakthrough in space technology. A LM-2C rocket carrying Nano-Satellite I (NS-1), which weighs just 25kg and an Experiment Satellite I, weighing 204kg blasted off at 11:59 p.m. on April 18,

  18. Companions to APOGEE Stars I: A Milky Way-Spanning Catalog of Stellar and Substellar Companion Candidates and their Diverse Hosts

    CERN Document Server

    Troup, Nicholas W; De Lee, Nathan; Carlberg, Joleen; Majewski, Steven R; Fernandez, Martin; Covey, Kevin; Chojnowski, S Drew; Pepper, Joshua; Nguyen, Duy T; Stassun, Keivan; Nguyen, Duy Cuong; Wisniewski, John P; Fleming, Scott W; Bizyaev, Dmitry; Frinchaboy, Peter M; García-Hernández, D A; Ge, Jian; Hearty, Fred; Meszaros, Szabolcs; Pan, Kaike; Prieto, Carlos Allende; Schneider, Donald P; Shetrone, Matthew D; Wilson, John; Zamora, Olga

    2016-01-01

    In its three years of operation, the Sloan Digital Sky Survey (SDSS-III) Apache Point Observatory Galactic Evolution Experiment (APOGEE-1) observed $>$14,000 stars with enough epochs over a sufficient temporal baseline for the fitting of Keplerian orbits. We present the custom orbit-fitting pipeline used to create this catalog, which includes novel quality metrics that account for the phase and velocity coverage of a fitted Keplerian orbit. With a typical RV precision of $\\sim100-200$ m s$^{-1}$, APOGEE can probe systems with small separation companions down to a few Jupiter masses. Here we present initial results from a catalog of 382 of the most compelling stellar and substellar companion candidates detected by APOGEE, which orbit a variety of host stars in diverse Galactic environments. Of these, 376 have no previously known small separation companion. The distribution of companion candidates in this catalog shows evidence for an extremely truncated brown dwarf (BD) desert with a paucity of BD companions o...

  19. Communications satellites - The experimental years

    Science.gov (United States)

    Edelson, B. I.

    1983-10-01

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

  20. Handbook of satellite applications

    CERN Document Server

    Madry, Scott; Camacho-Lara, Sergio

    2013-01-01

    Top space experts from around the world have collaborated to produce this comprehensive, authoritative, and clearly illustrated reference guide to the fast growing, multi-billion dollar field of satellite applications and space communications. This handbook, done under the auspices of the International Space University based in France, addresses not only system technologies but also examines market dynamics, technical standards and regulatory constraints. The handbook is a completely multi-disciplinary reference book that covers, in an in-depth fashion, the fields of satellite telecommunications, Earth observation, remote sensing, satellite navigation, geographical information systems, and geosynchronous meteorological systems. It covers current practices and designs as well as advanced concepts and future systems. It provides a comparative analysis of the common technologies and design elements for satellite application bus structures, thermal controls, power systems, stabilization techniques, telemetry, com...

  1. When the Milky Way turned-off the lights: APOGEE provides evidence of star formation "quenching" in our Galaxy

    CERN Document Server

    Haywood, M; Di Matteo, P; Snaith, O; Schultheis, M; Katz, D; Gomez, A

    2016-01-01

    Quenching, the cessation of star formation, is one of the most significant events in the life cycle of galaxies. We show here the first evidence that the Milky Way experienced a generalised quenching of its star formation at the end of its thick disk formation $\\sim$9 Gyr ago. Elemental abundances of stars studied as part of the APOGEE survey reveal indeed that in less than $\\sim$2 Gyr the star formation rate in our Galaxy dropped by an order-of-magnitude. Because of the tight correlation between age and alpha abundance, this event reflects in the dearth of stars along the inner disk sequence in the [Fe/H]-[$\\alpha$/Fe] plane. Before this phase, which lasted about 1.5 Gyr, the Milky Way was actively forming stars. Afterwards, the star formation resumed at a much lower level to form the thin disk. These events are very well matched by the latest observation of MW-type progenitors at high redshifts. In late type galaxies, quenching is believed to be related to a long and secular exhaustion of gas. In our Galaxy...

  2. The Rotation-Metallicity Relation for the Galactic Disk as Measured in the Gaia DR1 TGAS and APOGEE Data

    CERN Document Server

    Prieto, Carlos Allende; Cropper, Mark

    2016-01-01

    Previous studies have found that the Galactic rotation velocity-metallicity (V-[Fe/H]) relations for the thin and thick disk populations show negative and positive slopes, respectively. The first Gaia Data Release includes the Tycho-Gaia Astrometric Solution (TGAS) information, which we use to analyze the V-[Fe/H] relation for a strictly selected sample with high enough astrometric accuracy. We aim to arrive at an explanation for the slopes of the V-[Fe/H] relationship. We measure the V-[Fe/H] relation for thin and thick disk stars classified on the basis of their [$\\alpha$/Fe] and [Fe/H] abundances. We find dV/d[Fe/H]= -18 +/- 2 km/s/dex for stars in the thin disk and dV/d[Fe/H]= +23 +/- 10 km/s/dex for thick disk stars, so we confirm the different signs for the slopes. The negative value of dV/d[Fe/H] for thick disk stars is consistent with previous studies, but the combination of TGAS and APOGEE data provide higher precision, even though systematic errors could exceed +/-5 km/s/dex . Our average measuremen...

  3. Kinematics in the Galactic Bulge with APOGEE: II. High-Order Kinematical Moments and Comparison to Extragalactic Bar Diagnostics

    CERN Document Server

    Zasowski, G; Pérez, A E García; Martinez-Valpuesta, I; Johnson, J A; Majewski, S R

    2016-01-01

    Much of the inner Milky Way's (MW) global rotation and velocity dispersion patterns can be reproduced by models of secularly-evolved, bar-dominated bulges. More sophisticated constraints, including the higher moments of the line-of-sight velocity distributions (LOSVDs) and limits on the chemodynamical substructure, are critical for interpreting observations of the unresolved inner regions of extragalactic systems and for placing the MW in context with other galaxies. Here, we use SDSS-APOGEE data to develop these constraints, by presenting the first maps of the LOSVD skewness and kurtosis of metal-rich and metal-poor inner MW stars (divided at [Fe/H] = -0.4), and comparing the observed patterns to those that are seen both in N-body models and in extragalactic bars. Despite closely matching the mean velocity and dispersion, the models do not reproduce the observed LOSVD skewness patterns in different ways, which demonstrates that our understanding of the detailed orbital structure of the inner MW remains an im...

  4. Chemical tagging with APOGEE: Discovery of a large population of N-rich stars in the inner Galaxy

    CERN Document Server

    Schiavon, Ricardo P; Carrera, Ricardo; Lucatello, Sara; Robin, A C; Ness, Melissa; Martell, Sarah L; Smith, Verne V; Hernandez, D A Garcia; Manchado, Arturo; Schoenrich, Ralph; Bastian, Nate; Chiappini, Cristina; Shetrone, Matthew; Mackereth, J Ted; Williams, Rob A; Meszaros, Szabolcs; Prieto, Carlos Allende; Anders, Friedrich; Bizyaev, Dmitry; Beers, Timothy C; Chojnowski, S Drew; Cunha, Katia; Epstein, Courtney; Frinchaboy, Peter M; Perez, Ana E Garcia; Hearty, Fred R; Holtzman, Jon A; Johnson, Jennifer A; Kinemuchi, Karen; Majewski, Steven R; Muna, Demitri; Nidever, David L; Nguyen, Duy Cuong; O'Connell, Robert W; Oravetz, Daniel; Pan, Kaike; Pinsonneault, Marc; Schneider, Donald P; Schultheis, Matthias; Simmons, Audrey; Skrutskie, Michael F; Sobeck, Jennifer; Wilson, John C; Zasowski, Gail

    2016-01-01

    Formation of globular clusters (GCs), the Galactic bulge, or galaxy bulges in general, are important unsolved problems in Galactic astronomy. Homogeneous infrared observations of large samples of stars belonging to GCs and the Galactic bulge field are one of the best ways to study these problems. We report the discovery by APOGEE of a population of field stars in the inner Galaxy with abundances of N, C, and Al that are typically found in GC stars. The newly discovered stars have high [N/Fe], which is correlated with [Al/Fe] and anti-correlated with [C/Fe]. They are homogeneously distributed across, and kinematically indistinguishable from, other field stars in the same volume. Their metallicity distribution is seemingly unimodal, peaking at [Fe/H]~-1, thus being in disagreement with that of the Galactic GC system. Our results can be understood in terms of different scenarios. N-rich stars could be former members of dissolved GCs, in which case the mass in destroyed GCs exceeds that of the surviving GC system...

  5. The SDSS-III APOGEE Radial Velocity Survey of M dwarfs I: Description of Survey and Science Goals

    CERN Document Server

    Deshpande, R; Bender, C F; Mahadevan, S; Terrien, R C; Carlberg, J; Zasowski, G; Crepp, J; Rajpurohit, A S; Reyle, C; Nidever, D L; Schneider, D P; Prieto, C Allende; Bizyaev, D; Ebelke, G; Fleming, S W; Frinchaboy, P M; Ge, J; Hearty, F; Hernandez, J; Malanushenko, E; Malanushenko, V; Majewski, S R; Oravetz, D; Pan, K; Schiavon, R P; Shetrone, M; Simmons, A; Stassun, K G; Wilson, J C; Wisniewski, J

    2013-01-01

    We are carrying out a large ancillary program with the SDSS-III, using the fiber-fed multi-object NIR APOGEE spectrograph, to obtain high-resolution H-band spectra of more than 1200 M dwarfs. These observations are used to measure spectroscopic rotational velocities, radial velocities, physical stellar parameters, and variability of the target stars. Here, we describe the target selection for this survey and results from the first year of scientific observations based on spectra that is publicly available in the SDSS-III DR10 data release. As part of this paper we present RVs and vsini of over 200 M dwarfs, with a vsini precision of ~2 km/s and a measurement floor at vsini = 4 km/s. This survey significantly increases the number of M dwarfs studied for vsini and RV variability (at ~100-200 m/s), and will advance the target selection for planned RV and photometric searches for low mass exoplanets around M dwarfs, such as HPF, CARMENES, and TESS. Multiple epochs of radial velocity observations enable us to iden...

  6. DFH-3 Satellite Platform

    Institute of Scientific and Technical Information of China (English)

    RenShufang

    2005-01-01

    The DFH-3 satellite platform is designed and developed by China Academy of Space Technology (CAST). It is a medium capability communications satellite platform. The platform adopts threeaxis attitude stabilization control system, having solar array output power of 1.7kW by the end of its design lifetime of 8 years. Its mass is 2100kg with payload capacity of 220kg.

  7. Cooperative and cognitive satellite systems

    CERN Document Server

    Chatzinotas, Symeon; De Gaudenzi, Riccardo

    2015-01-01

    Cooperative and Cognitive Satellite Systems provides a solid overview of the current research in the field of cooperative and cognitive satellite systems, helping users understand how to incorporate state-of-the-art communication techniques in innovative satellite network architectures to enable the next generation of satellite systems. The book is edited and written by top researchers and practitioners in the field, providing a comprehensive explanation of current research that allows users to discover future technologies and their applications, integrate satellite and terrestrial systems

  8. 导航卫星多数表决恒包络技术研究%Majority Voting Technology for Constant Envenlope in Navigation Satellite

    Institute of Scientific and Technical Information of China (English)

    赵毅; 郑晋军; 刘崇华; 陈忠贵; 王璐

    2011-01-01

    In order to improve the efficiency of frequency, modern satellite navigation systems often transmit several signals via one channel. The direct linear combined signal , which is not a constant envelope one, will make a distorted wave shape when through high power amplifier (HPA) ,and it will also affect the performance of the navigation system. It is necessary to research the constant envelope technology for solving this problem. The majority voting , which has been used in deep space domain successfully, is a constant envelope technology for binary signal. Because of the characteristic of constant envelope, it allows the signal to go through C class HPA. This paper introduces the meaning of using the constant envelope technology and criteria of evaluating the constant envelope technology. The majority voting technology is also studied, including uniform weighting, nonuniform weighting and generalized majority arithmetic. Therefore, the simulation result of multiplexing efficiency and the power spectral density function are given. This paper could play a role of theoretical reference for satellite navigation signal desigr.%为了提高频带的利用率,现代卫星导航系统往往在一个信道内发送多路信号.直接的线性组合信号不是恒包络的信号,在通过功率放大器时会产生失真,影响信号的性能.为解决这一问题,引入了恒包络生成技术.多数表决算法是针对二进制信号的一种恒包络算法,目前已经成功应用于深空通信中的信号处理;其恒包络特性允许信号通过效率较高的C类功率放大器且不引起信号崎变.文章首先介绍了使用恒包络算法的意义和衡量恒包络算法优劣的评价准则,然后分别介绍了等功率、非等功率、通用的多数表决算法,并给出了复用技术效率变化的仿真结果、典型情况下的功率谱密度,可为卫星导航系统的信号设计提供理论参考.

  9. Small is Beautiful — Technology Trends in the Satellite Industry and Their Implications for Planetary Science Missions

    Science.gov (United States)

    Freeman, A.

    2017-02-01

    It’s an exciting time in the space business - new technologies being developed under the ‘NewSpace’ umbrella have some profound implications for planetary science missions over the next three decades.

  10. IP技术在卫星通信中的应用及发展趋势%The Application and Developing Trend of IP Technology in Satellite Communication

    Institute of Scientific and Technical Information of China (English)

    程磊; 孔博; 吴久银

    2012-01-01

    Internet Protocol(IP) technology has ubiquitous along with the development of communication,it is one of the hot points in the fields communication that combine IP technology with satellite communication(SATCOM).Addressed the characteristic of SATCOM,the paper analyses the peculiarity of SATCOM link in Internet and presents the im- provement of SATCOM link protocol,then predicts the developing trend of IP technology in SATCOM%随着通信的发展,IP技术已经泛化,将IP技术与卫星通信相结合的卫星IP网络是通信领域众多研究的热点之一。该文针对卫星通信的传输特性,分析了卫星链路在Intemet应用中的特点,介绍了对卫星链路协汉的改进,给出了当前卫星lP网络技术的发展趋势。

  11. Trajectory Design for the Transiting Exoplanet Survey Satellite (TESS)

    Science.gov (United States)

    Dichmann, Donald J.; Parker, Joel; Williams, Trevor; Mendelsohn, Chad

    2014-01-01

    The Transiting Exoplanet Survey Satellite (TESS) is a National Aeronautics and Space Administration (NASA) mission launching in 2017. TESS will travel in a highly eccentric orbit around Earth, with initial perigee radius near 17 Earth radii (Re) and apogee radius near 59 Re. The orbit period is near 2:1 resonance with the Moon, with apogee nearly 90 degrees out-of-phase with the Moon, in a configuration that has been shown to be operationally stable. TESS will execute phasing loops followed by a lunar flyby, with a final maneuver to achieve 2:1 resonance with the Moon. The goals of a resonant orbit with long-term stability, short eclipses and limited oscillations of perigee present significant challenges to the trajectory design. To rapidly assess launch opportunities, we adapted the SWM76 launch window tool to assess the TESS mission constraints. To understand the long-term dynamics of such a resonant orbit in the Earth-Moon system we employed Dynamical Systems Theory in the Circular Restricted 3-Body Problem (CR3BP). For precise trajectory analysis we use a high-fidelity model and multiple shooting in the General Mission Analysis Tool (GMAT) to optimize the maneuver delta-V and meet mission constraints. Finally we describe how the techniques we have developed can be applied to missions with similar requirements.

  12. Trajectory Design for the Transiting Exoplanet Survey Satellite

    Science.gov (United States)

    Dichmann, Donald J.; Parker, Joel J. K.; Williams, Trevor W.; Mendelsohn, Chad R.

    2014-01-01

    The Transiting Exoplanet Survey Satellite (TESS) is a National Aeronautics and Space Administration (NASA) mission, scheduled to be launched in 2017. TESS will travel in a highly eccentric orbit around Earth, with initial perigee radius near 17 Earth radii (Re) and apogee radius near 59 Re. The orbit period is near 2:1 resonance with the Moon, with apogee nearly 90 degrees out-of-phase with the Moon, in a configuration that has been shown to be operationally stable. TESS will execute phasing loops followed by a lunar flyby, with a final maneuver to achieve 2:1 resonance with the Moon. The goals of a resonant orbit with long-term stability, short eclipses and limited oscillations of perigee present significant challenges to the trajectory design. To rapidly assess launch opportunities, we adapted the Schematics Window Methodology (SWM76) launch window analysis tool to assess the TESS mission constraints. To understand the long-term dynamics of such a resonant orbit in the Earth-Moon system we employed Dynamical Systems Theory in the Circular Restricted 3-Body Problem (CR3BP). For precise trajectory analysis we use a high-fidelity model and multiple shooting in the General Mission Analysis Tool (GMAT) to optimize the maneuver delta-V and meet mission constraints. Finally we describe how the techniques we have developed can be applied to missions with similar requirements. Keywords: resonant orbit, stability, lunar flyby, phasing loops, trajectory optimization

  13. ESA's satellite communications programme

    Science.gov (United States)

    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.

  14. GPS satellite surveying

    CERN Document Server

    Leick, Alfred; Tatarnikov, Dmitry

    2015-01-01

    THE MOST COMPREHENSIVE, UP-TO-DATE GUIDE ON GPS TECHNOLOGY FOR SURVEYING Three previous editions have established GPS Satellite Surveying as the definitive industry reference. Now fully updated and expanded to reflect the newest developments in the field, this Fourth Edition features cutting-edge information on GNSS antennas, precise point positioning, real-time relative positioning, lattice reduction, and much more. Expert authors examine additional tools and applications, offering complete coverage of geodetic surveying using satellite technologies. The past decade has seen a major evolut

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

    Science.gov (United States)

    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.

  16. An Overview Of Operational Satellites Built By China: Communications Satellites (Part1)

    Institute of Scientific and Technical Information of China (English)

    Guang Bo

    2008-01-01

    @@ Communications satellite technology has seen great advances since Decemher 1958 when the Americans launched the first experimental communications satellite.Currently, satellite communications account for over 80 percent of the intercontinental communications traffic and 100 percent of international live TV broadcast, while taking part in domestic and regional services. Moreover, the satellite communication service is showing a favorable continuous growth tendency.

  17. When the Milky Way turned off the lights: APOGEE provides evidence of star formation quenching in our Galaxy

    Science.gov (United States)

    Haywood, M.; Lehnert, M. D.; Di Matteo, P.; Snaith, O.; Schultheis, M.; Katz, D.; Gómez, A.

    2016-05-01

    Quenching, the cessation of star formation, is one of the most significant events in the life cycle of galaxies. While quenching is generally thought to be linked to their central regions, the mechanism responsible for it is not known and may not even be unique. We show here the first evidence that the Milky Way experienced a generalised quenching of its star formation at the end of its thick-disk formation ~9 Gyr ago. The fossil record imprinted on the elemental abundances of stars studied in the solar vicinity and as part of the APOGEE survey (APOGEE is part of the Sloan Digital Sky Survey III) reveals indeed that in less than ~2 Gyr (from 10 to 8 Gyr ago) the star formation rate in our Galaxy dropped by an order of magnitude. Because of the tight correlation that exists between age and α abundance, the general cessation of the star formation activity reflects in the dearth of stars along the inner-disk sequence in the [Fe/H]-[α/Fe] plane. Before this phase, which lasted about 1.5 Gyr, the Milky Way was actively forming stars. Afterwards, the star formation resumed at a much lower level to form the thin disk. These events observed in our Galaxy are very well matched by the latest observation of MW-type progenitors at high redshifts. In late-type galaxies, the quenching mechanism is believed to be related to a long and secular exhaustion of gas. Our results show that in the Milky Way, the shut-down occurred on a much shorter timescale, while the chemical continuity between the stellar populations formed before and after the quenching indicates that it is not the exhaustion of the gas that was responsible for the cessation of the star formation. While quenching is generally associated with spheroids in the literature, our results show that it also occurs in galaxies like the Milky Way, where the classical bulge is thought to be small or non-existent, possibly when they are undergoing a morphological transition from thick to thin disks. Given the demographics of

  18. Satellite imagery technology in public health: analysis of site catchment areas for assessment of poliovirus circulation in Nigeria and Niger.

    Science.gov (United States)

    Takane, Marina; Yabe, Shizu; Tateshita, Yumiko; Kobayashi, Yusuke; Hino, Akihiko; Isono, Kazuo; Okayasu, Hiromasa; Diop, Ousmane M; Tadono, Takeo

    2016-11-21

    Environmental surveillance supplements the surveillance of acute flaccid paralysis by monitoring wastewater for poliovirus circulation. Building on previous work, we analysed wastewater flow to optimise selection and placement of sampling sites with higher digital surface model (DSM) resolution. The newly developed 5-m mesh DSM from the panchromatic, remote-sensing instruments for stereo mapping on-board the Japanese advanced land observing satellite was used to estimate catchment areas and flow of sewage water based on terrain topography. Optimal sampling sites for environmental surveillance were identified to maximise sensitivity to poliovirus circulation. Population data were overlaid to prioritise selection of catchment areas with dense populations. The results for Kano City, Nigeria were compared with an analysis based on existing 30- and 90-m mesh digital elevation model (DEM). Analysis based on 5-m mesh DSM was also conducted for three cities in Niger to prioritise the selection of new sites. The analysis demonstrated the feasibility of using DSMs to estimate catchment areas and population size for programme planning and outbreak response with respect to polio. Alternative sampling points in Kano City that would cover a greater population size have been identified and potential sampling sites in Niger are proposed. Comparison with lower-resolution DEMs suggests that the use of a 5-m mesh DSMs would be useful where the terrain is flat or includes small-scale topographic changes not captured by 30-m data searches.

  19. Chemical tagging with APOGEE: discovery of a large population of N-rich stars in the inner Galaxy

    Science.gov (United States)

    Schiavon, Ricardo P.; Zamora, Olga; Carrera, Ricardo; Lucatello, Sara; Robin, A. C.; Ness, Melissa; Martell, Sarah L.; Smith, Verne V.; García-Hernández, D. A.; Manchado, Arturo; Schönrich, Ralph; Bastian, Nate; Chiappini, Cristina; Shetrone, Matthew; Mackereth, J. Ted; Williams, Rob A.; Mészáros, Szabolcs; Allende Prieto, Carlos; Anders, Friedrich; Bizyaev, Dmitry; Beers, Timothy C.; Chojnowski, S. Drew; Cunha, Katia; Epstein, Courtney; Frinchaboy, Peter M.; García Pérez, Ana E.; Hearty, Fred R.; Holtzman, Jon A.; Johnson, Jennifer A.; Kinemuchi, Karen; Majewski, Steven R.; Muna, Demitri; Nidever, David L.; Nguyen, Duy Cuong; O'Connell, Robert W.; Oravetz, Daniel; Pan, Kaike; Pinsonneault, Marc; Schneider, Donald P.; Schultheis, Matthias; Simmons, Audrey; Skrutskie, Michael F.; Sobeck, Jennifer; Wilson, John C.; Zasowski, Gail

    2017-02-01

    Formation of globular clusters (GCs), the Galactic bulge, or galaxy bulges in general is an important unsolved problem in Galactic astronomy. Homogeneous infrared observations of large samples of stars belonging to GCs and the Galactic bulge field are one of the best ways to study these problems. We report the discovery by APOGEE (Apache Point Observatory Galactic Evolution Experiment) of a population of field stars in the inner Galaxy with abundances of N, C, and Al that are typically found in GC stars. The newly discovered stars have high [N/Fe], which is correlated with [Al/Fe] and anticorrelated with [C/Fe]. They are homogeneously distributed across, and kinematically indistinguishable from, other field stars within the same volume. Their metallicity distribution is seemingly unimodal, peaking at [Fe/H] ˜ -1, thus being in disagreement with that of the Galactic GC system. Our results can be understood in terms of different scenarios. N-rich stars could be former members of dissolved GCs, in which case the mass in destroyed GCs exceeds that of the surviving GC system by a factor of ˜8. In that scenario, the total mass contained in so-called `first-generation' stars cannot be larger than that in `second-generation' stars by more than a factor of ˜9 and was certainly smaller. Conversely, our results may imply the absence of a mandatory genetic link between `second-generation' stars and GCs. Last, but not least, N-rich stars could be the oldest stars in the Galaxy, the by-products of chemical enrichment by the first stellar generations formed in the heart of the Galaxy.

  20. Kinematics in the Galactic Bulge with APOGEE. II. High-Order Kinematic Moments and Comparison to Extragalactic Bar Diagnostics

    Science.gov (United States)

    Zasowski, G.; Ness, M. K.; García Pérez, A. E.; Martinez-Valpuesta, I.; Johnson, J. A.; Majewski, S. R.

    2016-12-01

    Much of the inner Milky Way’s (MW) global rotation and velocity dispersion patterns can be reproduced by models of secularly evolved, bar-dominated bulges. More sophisticated constraints, including the higher moments of the line-of-sight velocity distributions (LOSVDs) and limits on the chemodynamical substructure, are critical for interpreting observations of the unresolved inner regions of extragalactic systems and for placing the MW in context with other galaxies. Here, we use SDSS-APOGEE data to develop these constraints, by presenting the first maps of the skewness and kurtosis of the LOSVDs of metal-rich and metal-poor inner MW stars (divided at [Fe/H] = -0.4), and comparing the observed patterns to those that are seen both in N-body models and in extragalactic bars. Despite closely matching the mean velocity and dispersion, the models do not reproduce the observed skewness patterns of the LOSVDs in different ways, which demonstrates that our understanding of the detailed orbital structure of the inner MW remains an important regime for improvement. We find evidence in the MW of the skewness-velocity correlation that is used as a diagnostic of extragalactic bars/bulges. This correlation appears in metal-rich stars only, providing further evidence for different evolutionary histories of chemically differentiated populations. We connect these skewness measurements to previous work on high-velocity “peaks” in the inner Galaxy, confirming the presence of that phenomenon, and we quantify the cylindrical rotation of the inner Galaxy, finding that the latitude-independent rotation vanishes outside l ˜ 7°. Finally, we evaluate the MW data in the light of selected extragalactic bar diagnostics and discuss the progress and challenges in using the MW as a resolved analog of unresolved stellar populations.

  1. Development of the European Small Geostationary Satellite SGEO

    Science.gov (United States)

    Lübberstedt, H.; Schneider, A.; Schuff, H.; Miesner, Th.; Winkler, A.

    2008-08-01

    The SGEO product portfolio, ranging from Satellite platform delivery up to in-orbit delivery of a turnkey system including satellite and ground control station, is designed for applications ranging from TV Broadcast to multimedia applications, Internet access, mobile or fixed services in a wide range of frequency bands. Furthermore, Data Relay missions such as the European Data Relay Satellite (EDRS) as well as other institutional missions are targeted. Key design features of the SGEO platform are high flexibility and modularity in order to accommodate a very wide range of future missions, a short development time below two years and the objective to build the system based on ITAR free subsystems and components. The system will provide a long lifetime of up to 15 years in orbit operations with high reliability. SGEO is the first European satellite to perform all orbit control tasks solely by electrical propulsion (EP). This design provides high mass efficiency and the capability for direct injection into geostationary orbit without chemical propulsion (CP). Optionally, an Apogee Engine Module based on CP will provide the perigee raising manoeuvres in case of a launch into geostationary transfer orbit (GTO). This approach allows an ideal choice out of a wide range of launcher candidates in dependence of the required payload capacity. SGEO will offer to the market a versatile and high performance satellite system with low investment risk for the customer and a short development time. This paper provides an overview of the SGEO system key features and the current status of the SGEO programme.

  2. The TAOS/STEP Satellite

    OpenAIRE

    Edwards, David; Hosken, Robert

    1995-01-01

    The Technology for Autonomous Operational Survivability / Space Test Experiments Platform (TAOS/STEP) satellite was launched on a Taurus booster from Vandenberg Air Force Base into a nearly circular, 105 degree inclined orbit on March 13, 1994. The purpose of this satellite is twofold: 1) to test a new concept in multiple procurements of fast-track modular satellites and 2) to test a suite of Air Force Phillips Laboratory payloads in space. The TAOS payloads include the Microcosm Autonomous N...

  3. Satellite RNAs and Satellite Viruses.

    Science.gov (United States)

    Palukaitis, Peter

    2016-03-01

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

  4. Direct Broadcast Satellite: Radio Program

    Science.gov (United States)

    Hollansworth, James E.

    1992-01-01

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

  5. Delivery of Instructional Materials Using a Communications Satellite.

    Science.gov (United States)

    Bransford, Louis A.; Diebler, Mary

    During the past decade, satellite technology has grown increasingly more sophisticated. Satellites are being used in public interest activities, especially through the Public Service Satellite Consortium. But what about the field of education? How can education, especially vocational education, make use of satellite communications technology? In…

  6. Centriolar satellites

    DEFF Research Database (Denmark)

    Tollenaere, Maxim A X; Mailand, Niels; Bekker-Jensen, Simon

    2015-01-01

    Centriolar satellites are small, microscopically visible granules that cluster around centrosomes. These structures, which contain numerous proteins directly involved in centrosome maintenance, ciliogenesis, and neurogenesis, have traditionally been viewed as vehicles for protein trafficking...... highlight newly discovered regulatory mechanisms targeting centriolar satellites and their functional status, and we discuss how defects in centriolar satellite components are intimately linked to a wide spectrum of human diseases....

  7. High-resolution H-band spectroscopy of Be stars with SDSS-III/apogee. I. New Be stars, line identifications, and line profiles

    Energy Technology Data Exchange (ETDEWEB)

    Chojnowski, S. Drew; Majewski, Steven R.; Hall, Matthew; Beaton, Rachael; Burton, Adam; Damke, Guillermo; Wilson, John [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Whelan, David G. [Department of Physics, Austin College, 900 N. Grand Ave., Sherman, TX 75090 (United States); Wisniewski, John P. [Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks St., Norman, OK 73019 (United States); Shetrone, Matthew [Department of Astronomy, The University of Texas at Austin, 2515 Speedway, Stop C1400 Austin, Texas 78712-1205 (United States); Eikenberry, Steve [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611-2055 (United States); Hasselquist, Sten; Holtzman, Jon A.; Brewington, Howard; Brinkmann, J. [Apache Point Observatory and New Mexico State University, P.O. Box 59, Sunspot, NM, 88349-0059 (United States); Mészáros, Szabolcs [ELTE Gothard Astrophysical Observatory, 1H-9704 Szombathely, Szent Imre herceg st. 112 (Hungary); Nidever, David [Department of Astronomy, University of Michigan, 830 Dennison, 500 Church St., Ann Arbor, MI 48109-1042 (United States); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Zasowski, Gail [Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center for Physics and Astronomy, Room 366, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Bizyaev, Dmitry, E-mail: drewski@virginia.edu [Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802 (United States); and others

    2015-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has amassed the largest ever collection of multi-epoch, high-resolution (R∼22,500), H-band spectra for B-type emission line (Be) stars. These stars were targeted by APOGEE as telluric standard stars and subsequently identified via visual inspection as Be stars based on H i Brackett series emission or shell absorption in addition to otherwise smooth continua and occasionally non-hydrogen emission features. The 128/238 APOGEE Be stars for which emission had never previously been reported serve to increase the total number of known Be stars by ∼6%. Because the H band is relatively unexplored compared to other wavelength regimes, we focus here on identification of the H-band lines and analysis of the emission peak velocity separations (Δv{sub p}) and emission peak intensity ratios (V/R) of the usually double-peaked H i and non-hydrogen emission lines. H i Br11 emission is found to preferentially form in the circumstellar disks at an average distance of ∼2.2 stellar radii. Increasing Δv{sub p} toward the weaker Br12–Br20 lines suggests these lines are formed interior to Br11. By contrast, the observed IR Fe ii emission lines present evidence of having significantly larger formation radii; distinctive phase lags between IR Fe ii and H i Brackett emission lines further supports that these species arise from different radii in Be disks. Several emission lines have been identified for the first time including C i 16895, a prominent feature in the spectra for almost a fifth of the sample and, as inferred from relatively large Δv{sub p} compared to the Br11–Br20, a tracer of the inner regions of Be disks. Emission lines at 15760 Å and 16781 Å remain unidentified, but usually appear along with and always have similar line profile morphology to Fe ii 16878. Unlike the typical metallic lines observed for Be stars in the optical, the H-band metallic lines, such as Fe ii 16878, never exhibit any

  8. Satellite theory

    Science.gov (United States)

    Kozai, Y.

    1981-04-01

    The dynamical characteristics of the natural satellite of Mars, Jupiter, Saturn, Uranus and Neptune are analyzed on the basis of the solar tidal perturbation factor and the oblateness factor of the primary planet for each satellite. For the inner satellites, for which the value of the solar tidal factor is much smaller than the planetary oblateness factor, it is shown that the eccentricity and inclination of satellite orbits are generally very small and almost constant; several pairs of inner satellites are also found to exhibit commensurable mean motions, or secular accelerations in mean longitude. In the case of the outer satellites, for which solar perturbations are dominant, secular perturbations and long-period perturbations may be derived by the solution of equations of motion reduced to one degree of freedom. The existence of a few satellites, termed intermediary satellites, for which the solar tidal perturbation is on the order of the planetary oblateness factor, is also observed, and the pole of the orbital plane of the satellite is noted to execute a complex motion around the pole of the planet or the orbital plane of the planet.

  9. Communication satellite system beyond the year 2000

    Science.gov (United States)

    Robertson, G. J.; Fourquet, J. M.

    1991-10-01

    The primary evolutionary factors of satellite communications technologies are reviewed based on the results of a study of novel satellite developments. A critical evaluation of the viability and availability of the technologies is utilized in conjunction with market forecasts to determine promising commercial strategies. Modern technologies are almost prepared for the development of a class of communications satellites and include bandwidth utilization, spacecraft bus modularity, and functional integration.

  10. Satellite Teleconferencing in the Caribbean.

    Science.gov (United States)

    Sankar, Hollis C.

    1985-01-01

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

  11. Preliminary Investigation of the Satellite Gravitational Red Shift Experiment

    Science.gov (United States)

    Zacharias, J. R.; Searle, C. L.; Graham, J. W.; Badessa, R. S.; Bates, V. J.; Kent, R. L.

    1961-01-01

    The work performed under this contract involved study, design, and construction of experimental equipment to perform a short-term measurement of the gravitational red shift. In the system designed, phase comparison techniques are employed so that the time interval required to obtain a single measurement for one altitude is of the order of one minute. An elliptical orbit was chosen to permit measurement of frequency shift as a function of altitude. One particularly attractive orbit is that having a 12-hour orbiting period (perigee, 270 miles, apogee 24,800 miles). This orbit, shown in Fig. 1, allows continuous measurements to be made over an 11-hour interval during which time the altitude is varying greatly. Measurements can not be made for the succeeding 14 hours. Since the variation of frequency difference with altitude is of greatest interest, a fixed offset or a slow drift between the oscillator on the ground and. the oscillator in the satellite will not invalidate the measurements.

  12. Tactical Satellite 3

    Science.gov (United States)

    Davis, T. M.; Straight, S. D.; Lockwook, R. B.

    2008-08-01

    Tactical Satellite 3 is an Air Force Research Laboratory Science and Technology (S&T) initiative that explores the capability and technological maturity of small, low-cost satellites. It features a low cost "plug and play" modular bus and low cost militarily significant payloads - a Raytheon developed Hyperspectral imager and secondary payload data exfiltration provided by the Office of Naval Research. In addition to providing for ongoing innovation and demonstration in this important technology area, these S&T efforts also help mitigate technology risk and establish a potential concept of operations for future acquisitions. The key objectives are rapid launch and on-orbit checkout, theater commanding, and near-real time theater data integration. It will also feature a rapid development of the space vehicle and integrated payload and spacecraft bus by using components and processes developed by the satellite modular bus initiative. Planned for a late summer 2008 launch, the TacSat-3 spacecraft will collect and process images and then downlink processed data using a Common Data Link. An in-theater tactical ground station will have the capability to uplink tasking to spacecraft and will receive full data image. An international program, the United Kingdom Defence Science and Technology Laboratory (DSTL) and Australian Defence Science and Technology Organisation (DSTO) plan to participate in TacSat-3 experiments.

  13. Plasma Turbulence in Earth's Magnetosheath Observed by the Magnetospheric Multiscale Mission over the First Sub-Solar Apogee Pass

    Science.gov (United States)

    Mackler, D. A.; Avanov, L. A.; Boardsen, S. A.; Giles, B. L.; Pollock, C.; Smith, S. E.; Uritsky, V. M.

    2016-12-01

    search for localized gradient steepening where turbulent dissipation may be occurring. Additionally, we take advantage of multi-spacecraft observations to compute the current density in the turbulent region. This analysis is done over multiple burst periods during MMS' first sub-solar apogee pass from November 2015 to January 2016.

  14. Satellite-Based Technologies in Use for Extreme Nocturnal Mountain Rescue Operations: a Synergetic Approach Applying Geophysical Principles

    Science.gov (United States)

    Buchroithner, Manfred F.; Ehlert, Guido; Hetze, Bernd; Kohlschmidt, Horst; Prechtel, Nikolas

    2014-06-01

    Mountain-rescue operations require rapid response whilst also ensuring the security of the rescue teams. Rescuing people in a big rock-face is even more difficult if night or fog prevent sight. The paper presents a technical solution to optimally support, under these aggravated conditions, the location of the casualties and the navigation of the rescue team(s) in a rock-face from a coordination station. In doing so, standard components like a smartphones with GPS functionality, a data communication on a client-server basis and VR visualisation software have been adapted to the specific requirements. Remote support of the navigation in steep rocky terrain requires a highly accurate wall model which permits the local experts of the coordination station to dependably estimate geometry and structure of the rock along the rescue route and to convey necessary directives to the retrieval team. Based on terrestrial laser-scans from different locations, such a model has been generated for the mighty Dachstein South Face (Austria) and texturised with digital photographs. Over a twelve-month period, a transdisciplinary team of the Dresden University of Technology (Informatics, Electrical Engineering, Cartography) developed and integrated the various technical modules of the mountain-rescue support-system (digital rock-face model, optimised GPS data transmission between mobile device, server and client, data filtering, and dynamic visualisation component). In summer 2011 the proper functioning of the prototype was demonstrated in a rescue exercise under foggy dusk conditions.

  15. Space communication link propagation data for selected cities within the multiple beam and steerable antenna coverage areas of the advanced communications technology satellite

    Science.gov (United States)

    Manning, Robert M.

    1988-01-01

    Rain attenuation propagation data for 68 cities within the coverage area of the multiple beam and steerable antennas of the Advanced Communications Technology Satellite (ACTS) are presented. These data provide the necessary data base for purposes of communication link power budgeting and rain attenuation mitigation controller design. These propagation parameters are derived by applying the ACTS Rain Attenuation Prediction Model to these 68 locations. The propagation parameters enumerated in tabular form for each location are as follows: (1) physical description of the link and location (e.g., latitude, longitude, antenna elevation angle, etc.), link availability versus attenuation margin (also in graphical form), fading time across fade depths of 3, 5, 8, and 15 dB versus fade duration, and required fade control response time for controller availabilities of 99.999, 99.99, 99.9, and 99 percent versus sub-threshold attenuation levels. The data for these specific locations can be taken to be representative of regions near these locations.

  16. A Kinematic Survey in the Perseus Molecular Cloud: Results from the APOGEE Infrared Survey of Young Nebulous Clusters (IN-SYNC)

    Science.gov (United States)

    Covey, Kevin R.; Cottaar, M.; Foster, J. B.; Nidever, D. L.; Meyer, M.; Tan, J.; Da Rio, N.; Flaherty, K. M.; Stassun, K.; Frinchaboy, P. M.; Majewski, S.; APOGEE IN-SYNC Team

    2014-01-01

    Demographic studies of stellar clusters indicate that relatively few persist as bound structures for 100 Myrs or longer. If cluster dispersal is a 'violent' process, it could strongly influence the formation and early evolution of stellar binaries and planetary systems. Unfortunately, measuring the dynamical state of 'typical' (i.e., ~300-1000 member) young star clusters has been difficult, particularly for clusters still embedded within their parental molecular cloud. The near-infrared spectrograph for the Apache Point Observatory Galactic Evolution Experiment (APOGEE), which can measure precise radial velocities for 230 cluster stars simultaneously, is uniquely suited to diagnosing the dynamics of Galactic star formation regions. We give an overview of the INfrared Survey of Young Nebulous Clusters (IN-SYNC), an APOGEE ancillary science program that is carrying out a comparative study of young clusters in the Perseus molecular cloud: NGC 1333, a heavily embedded cluster, and IC 348, which has begun to disperse its surrounding molecular gas. These observations appear to rule out a significantly super-virial velocity dispersion in IC 348, contrary to predictions of models where a cluster's dynamics is strongly influenced by the dispersal of its primordial gas. We also summarize the properties of two newly identified spectroscopic binaries; binary systems such as these play a key role in the dynamical evolution of young clusters, and introduce velocity offsets that must be accounted for in measuring cluster velocity dispersions.

  17. Broadcast satellite service: The international dimension

    Science.gov (United States)

    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.

  18. 星载光电振荡器(OEO)实现方法研究%Research on Optoelectronic Oscillator (OEO) Technology for Satellite Payloads

    Institute of Scientific and Technical Information of China (English)

    梁栋; 谭庆贵; 蒋炜; 幺周石

    2015-01-01

    文章针对未来卫星领域对高频率、低相位噪声微波本振源发展需求,提出一种适应于星载应用的光电振荡器实现方法。首先介绍了光电振荡器应用背景、技术特点及发展现状。之后详细分析了星载光电振荡器的设计方法,给出了光电振荡器的振荡阀值、产生毫米波频率、幅度数学模型等,最后对光电振荡器的相位噪声性能进行详细分析。分析表明,利用光电振荡器能够产生超低相位噪声(-163dBc/Hz @10KHz)的微波本振信号,且光电振荡器的相位噪声和振荡频率无关,星载光电振荡器为未来卫星领域提供一种可行的微波本振信号生成方法。%An optoelectronic oscillator ( OEO) method for Satellite Payloads is analyzed,which is used to meet the de-mands of aerospace for high frequency and low phase noise signal. Firstly, the application background and technology char-acteristic of the OEO are introduced. Secondly,the principle,the oscillator threshold, the frequency and the amplitude of the OEO are discussed with mathematical method. Finally, the phase noise performance of the OEO is analyzed in detail. The result shows that the OEO can generate microwave signal with high performance( -163dBc/Hz @10KHz), and the phase noise of the microwave signal is independent of the oscillator frequency. The OEO can meet the demands of microwave signal generating for satellite payloads.

  19. Satellite Geomagnetism

    DEFF Research Database (Denmark)

    Olsen, Nils; Stolle, Claudia

    2012-01-01

    Observations of Earth’s magnetic field from space began more than 50 years ago. A continuous monitoring of the field using low Earth orbit (LEO) satellites, however, started only in 1999, and three satellites have taken highprecision measurements of the geomagnetic field during the past decade...... ability to characterize and understand the many sources that contribute to Earth’s magnetic field. In this review, we summarize investigations of Earth’s interior and environment that have been possible through the analysis of high-precision magnetic field observations taken by LEO satellites........ The unprecedented time-space coverage of their data opened revolutionary new possibilities for monitoring, understanding, and exploring Earth’s magnetic field. In the near future, the three-satellite constellation Swarm will ensure continuity of such measurement and provide enhanced possibilities to improve our...

  20. Geostationary satellites collocation

    CERN Document Server

    Li, Hengnian

    2014-01-01

    Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

  1. Satellite (Natural)

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    In its most general sense, any celestial object in orbit around a similar larger object. Thus, for example, the Magellanic Clouds are satellite galaxies of our own Milky Way galaxy. Without qualification, the term is used to mean a body in orbit around a planet; an alternative term is moon. The term natural satellite distinguishes these bodies from artificial satellites—spacecraft placed in orbi...

  2. Satellite delivery of B-ISDN services

    Science.gov (United States)

    Kwan, R. K.; Price, K. M.; Chitre, D. M.; White, L. W.; Henderson, T. R.

    1992-01-01

    This paper will address the role of technology in the satellite delivery of B-ISDN services. Satellites excel in serving remote users and in providing multicast and broadcast services. Benefits to potential users employing these satellite broadband services will be examined together with their respective network architecture. Two application requirements are then proposed. The critical technologies needed in the realization of these architectures will be identified.

  3. Advanced communications technology satellite high burst rate link evaluation terminal power control and rain fade software test plan, version 1.0

    Science.gov (United States)

    Reinhart, Richard C.

    1993-01-01

    The Power Control and Rain Fade Software was developed at the NASA Lewis Research Center to support the Advanced Communications Technology Satellite High Burst Rate Link Evaluation Terminal (ACTS HBR-LET). The HBR-LET is an experimenters terminal to communicate with the ACTS for various experiments by government, university, and industry agencies. The Power Control and Rain Fade Software is one segment of the Control and Performance Monitor (C&PM) Software system of the HBR-LET. The Power Control and Rain Fade Software automatically controls the LET uplink power to compensate for signal fades. Besides power augmentation, the C&PM Software system is also responsible for instrument control during HBR-LET experiments, control of the Intermediate Frequency Switch Matrix on board the ACTS to yield a desired path through the spacecraft payload, and data display. The Power Control and Rain Fade Software User's Guide, Version 1.0 outlines the commands and procedures to install and operate the Power Control and Rain Fade Software. The Power Control and Rain Fade Software Maintenance Manual, Version 1.0 is a programmer's guide to the Power Control and Rain Fade Software. This manual details the current implementation of the software from a technical perspective. Included is an overview of the Power Control and Rain Fade Software, computer algorithms, format representations, and computer hardware configuration. The Power Control and Rain Fade Test Plan provides a step-by-step procedure to verify the operation of the software using a predetermined signal fade event. The Test Plan also provides a means to demonstrate the capability of the software.

  4. National Satellite Disaster Reduction Application Service

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The groundbreaking ceremony for National Satellite Disaster Reduction Application Service was held on January 22,2008 in Beijing.The establishment of the center will further improve the disaster monitoring system using remote sensing technology and provides a platform for the application of remote sensing technology and satellite constellation in China's disaster reduction and relief services.

  5. Plan of advanced satellite communication experiments using ETS-6

    Science.gov (United States)

    Ikegami, Tetsushi

    1989-01-01

    In 1992, an Engineering Test Satellite 6 is scheduled to be launched by an H-2 rocket. The missions of ETS-6 are to establish basic technologies of inter-satellite communications using S-band, millimeter waves and optical beams and of fixed and mobile satellite communications using multibeam antenna on board the satellite. A plan of the experiments is introduced.

  6. China Land Observation Satellite Third User Conference Promotes The Applications Of Domestic Satellite Data

    Institute of Scientific and Technical Information of China (English)

    Zong He

    2009-01-01

    @@ China Land Observation Satellite Third User Conference with the theme of "Strengthening cooperation,enlarging sharing and promoting the application of domestic satellite data" was held on July 16,2009 in Beijing. The conference was hosted by China Centre for Resources Satellite Data and Applications(CRESDA),a subsidiary of China Aerospace Science and Technology Corporation (CASC).

  7. Sky alert! when satellites fail

    CERN Document Server

    Johnson, Les

    2013-01-01

    How much do we depend on space satellites? Defense, travel, agriculture, weather forecasting, mobile phones and broadband, commerce...the list seems endless. But what would our live be like if the unimaginable happened and, by accident or design, those space assets disappeared? Sky Alert! explores what our world would be like, looking in turn at areas where the loss could have catastrophic effects. The book - demonstrates our dependence on space technology and satellites; - outlines the effect on our economy, defense, and daily lives if satellites and orbiting spacecraft were destroyed; - illustrates the danger of dead satellites, spent rocket stages, and space debris colliding with a functioning satellites; - demonstrates the threat of dramatically increased radiation levels associated with geomagnetic storms; - introduces space as a potential area of conflict between nations.

  8. Two Groups of Red Giants with Distinct Chemical Abundances in the Bulge Globular Cluster NGC 6553 Through the Eyes of APOGEE

    Science.gov (United States)

    Tang, Baitian; Cohen, Roger; Geisler, Douglas; Schiavon, Ricardo P.; Majewski, Steven R.; Villanova, Sandro; Carrera, Ricardo; Zamora, Olga; Garcia-Hernandez, D.; Shetrone, Matthew D.; Frinchaboy, Peter M.; Fernandez Trincado, Jose Gregorio; APOGEE Team

    2017-01-01

    Multiple populations revealed in globular clusters (GCs) are important windows to the formation and evolution of these stellar systems. The metal-rich GCs in the Galactic bulge are an indispensable part of this picture, but the high optical extinction in this region has prevented extensive research. In this work, we use the high resolution near-infrared (NIR) spectroscopic data from APOGEE to study the chemical abundances of NGC 6553, which is one of the most metal-rich bulge GCs. We identify ten red giants as cluster members using their positions, radial velocities, iron abundances, and NIR photometry. Our sample stars show a mean radial velocity of -0.14 km/s, and a mean [Fe/H] of -0.15. We clearly separate two populations of stars in C and N in this GC for the first time. NGC 6553 is the most metal-rich GC where the multiple stellar population phenomenon is found until now. Substantial chemical variations are also found in Na, O, and Al. However, the two populations show similar Si, Ca, and iron-peak element abundances. Therefore, we infer that the CNO, NeNa, and MgAl cycles have been activated, but the MgAl cycle is too weak to show its effect on Mg. The Si leakage from the MgAl cycle is negligible. Type Ia and Type II supernovae do not seem to have significantly polluted the second generation stars. Comparing the APOGEE results with other GC studies, we find that NGC 6553 shows similar chemical variations as other relatively metal-rich GCs. We also confront current GC formation theories with our results, and suggest possible avenues for improvement in the models.

  9. Scientific Satellites

    Science.gov (United States)

    1967-01-01

    followed Hale’s into orbit. In 1879, Jules Verne wrote about launching small satellites with a gun possessing a muzzle velocity of 10 000 m/sec (ref. 3...was activated in 1950.11 It was located only a few tens of miles from the spot where Jules Verne had his Baltimore Gun Club fire a manned projectile to...principle, satellites can be launched by a single impulse applied at the Earth’s surface-say, with a large cannon, & la Jules Verne (sec. 8-3). In

  10. Satellite communications principles and applications

    CERN Document Server

    Calcutt, David

    1994-01-01

    Satellites are increasingly used for global communications, as well as for radio and television transmissions. With the growth of mobile communications, and of digital technology, the use of satellite systems is set to expand substantially and already all students of electronics or communications engineering must study the subject.This book steers a middle path between offering a basic understanding of the process of communication by satellite and the methodology used; and the extensive mathematical analysis normally adopted in similar texts. It presents the basic concepts, using as mu

  11. Man-Made Moons: Satellite Communications for Schools.

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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.

  13. Spanish Earth Observation Satellite System

    Science.gov (United States)

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

    2010-12-01

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

  14. 基于卫星导航系统的高速列车定位技术研究%Research on High-speed Train Positioning Technology Based on Satellite Navigation System

    Institute of Scientific and Technical Information of China (English)

    李卫东; 侯丽虹

    2016-01-01

    In this paper,we first introduce the development of a global navigation satellite system and analyze its per-formance.By combining our research results and the application of a train positioning technology that uses domestic and international satellite navigation systems,we divide the train positioning technology into four categories.Then, we comprehensively analyze the performance of the train positioning technology with respect to accuracy,effective-ness,and safety integrity;summarize the existing problems;and suggest solutions.Finally,we make recommenda-tions regarding the future development of high-speed train positioning technology based on satellite navigation.%首先,介绍全球卫星导航系统的发展状况,对比分析全球卫星导航系统性能。并结合国内外基于卫星导航系统的列车定位技术的研究成果和应用情况,将列车定位技术分为四大类。然后,从精准性、有效性、安全完整性三个方面对列车定位技术综合性能进行分析,总结其存在的问题并给出解决方法。最后对基于卫星导航的高速列车定位技术的未来发展趋势进行展望。

  15. Cibola flight experiment satellite

    Science.gov (United States)

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

    2004-11-01

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

  16. Perception via satellite

    Science.gov (United States)

    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.

  17. Solar power satellites (SPS) and international law. The system of international law governing science and technology projects for energy source development in outer space (Solar power satellites, lunar power systems, Helium-3 project); Solar Power Satellites und Voelkerrecht. Voelkerrechtliche Aspekte von Grossprojekten zur Energiegewinnung aus Weltraumressourcen (Solar Power Satellites, Lunar Power Systems, Helium-3-Projekt)

    Energy Technology Data Exchange (ETDEWEB)

    Will, M.

    2000-07-01

    In addition to the utilization of renewable energy sources on earth, particular interest has been directed since the late 1960s to the exploitation of the energy of the sun via solar power satellites (SPS), and of other energy sources in outer space. The dissertation on hand presents a comprehensive survey and commented analysis, together with an exhaustive bibliography, of the available relevant international laws and treaties and regulatory framework that have been developed by the international legal community since the beginning of the R and D activities and now form the legal system governing the peaceful uses of solar power plants and other energy sources in outer space. The specific legal provisions and their application in the context of existing international laws and treaties are discussed in great depth. (CB) [German] Neben der Nutzung regenerativer Energiequellen auf der Erde ist seit Ende der sechziger Jahre die Errichtung und Nutzung von Solarenergiesatelliten (SPS) von besonderem Interesse. Die Doktorarbeit legt eine umfangreiche, ausfuehrlich erlaeuterte Dokumentation vor ueber die Entwicklung und den derzeitigen Stand von internationalem Recht und Vertraegen, die spezifisch fuer die F und E-Aktivitaeten und die Anwendung der SPS und anderer Energiequellen im Weltraum erforderlich und entwickelt wurden, sowie auch deren Einbettung in und Zusammenwirken mit bestehendem Voelkerrecht und internationalen Vereinbarungen. (CB)

  18. Routing Technology Research for LEO Satellite Constellation Networks%低轨道卫星星座网络路由研究

    Institute of Scientific and Technical Information of China (English)

    蒋文娟; 宗鹏

    2011-01-01

    Because of the particular features of LEO satellite networks, such as dynamic topology, non-homogeneous traffic distribution,limited power and processing, new satellite routing approaches should be developed. How to design simple and efficient routing algorithm becomes the hot topic of LEO satellite networks. Analyze the characteristics of LEO satellite networks, and then survey the cunrrent LEO satellite routing algorithms classified with the geometric model, handoff and onboard processing capability. Typical algorithms of each class are presented and their advantages, suitable environment and shortcomings with a detailed comprehensive comparison are discussed. The end of the paper points out the future research field for LFO satellite routing prob1em.%拓扑时变性、承载业务分布不均衡以及星上资源有限,使得设计新的低轨道卫星星座网络路由算法迫在眉睫.如何设计简单、高效的低轨道卫星星座路由成为当前卫星网络研究的热点问题.深入剖析了LEO卫星网络的特点,从几何模型、切换以及星上处理能力三个视角出发,分类综述了LEO卫星路由算法,阐述了各类路由的典型算法,讨论了每种算法的优点和适用环境,剖析了其中存在的问题,并对它们进行了综合对比.最后指出了LEO卫星路由算法进一步的研究方向.

  19. French-Language Satellite TV in the Classroom.

    Science.gov (United States)

    Rose, Russell G.

    1995-01-01

    This article describes the elements of satellite technology, provides information on French and other foreign-language programming, and offers suggestions for using satellite television in the classroom. (Author/JL)

  20. Investigation on Satellite-borne High-power Solid-state Power Amplifier Technology and Experiment%星载高功率固态功放关键技术与实验研究

    Institute of Scientific and Technical Information of China (English)

    武小坡; 赵海洋; 奚松涛

    2014-01-01

    该文结合某星载集中式固态发射机的高功率固态功率放大器,从星载应用着手,重点从高功率密度热设计、微放电防护设计、电磁兼容性设计等方面介绍了星载高功率固态功放关键性技术的设计方法,并且通过相关的真空环境试验验证了功率放大器组件设计方法的正确性和真空环境适应性。%Based on the research and development efforts of satellite-borne lumped solid-state transmitters, the design of a satellite-borne high-power microwave amplifier module is introduced. Focusing on satellite-borne applications, aspects of the high-power density thermal design, multipactor proof design, EMC design and so on, which are critical technologies for a solid-state power amplifier, are discussed. Subsequently, experiments are used to verify the concept.

  1. Global navigation satellite systems and their applications

    CERN Document Server

    Madry, Scott

    2015-01-01

    Dr. Madry, one of the world's leading experts in the field, provides in a condensed form a quick yet comprehensive overview of satellite navigation. This book concisely addresses the latest technology, the applications, the regulatory issues, and the strategic implications of satellite navigation systems. This assesses the strengths and weaknesses of satellite navigation networks and review of all the various national systems now being deployed and the motivation behind the proliferation of these systems.

  2. OPTIS - A satellite test of Special and General Relativity

    Science.gov (United States)

    Dittus, H.; Lämmerzahl, C.; Peters, A.; Schiller, S.

    OPTIS has been proposed as a small satellite platform in a high elliptical orbit (apogee 40,000 km, perigee 10,000 km) and is designed for high precision tests of foundations of Special and General Relativity. The experimental set-up consists of two ultrastable Nd:YAG lasers, two crossed optical resonators (monolithic cavities), an atomic clock, and an optical comb generator. OPTIS enables (1) a Michelson- Morley experiment to test the isotropy of light propagation (constancy of light speed, dc/c) with an accuracy of 1 part in 101 8 , (2) a Kennedey-Thorndike experiment to measure the independence of the light speed from the velocity of the laboratory in the order of 1 part in 101 6 , and (3) a test of the gravitational red shift by comparing the atomic clock and an optical clock on a precision level of 1 part in 104 . To avoid any influence from atmospheric drag, solar radiation, or earth albedo, the satellite needs drag free control, to depress the residual acceleration down to 10-14 m/s 2 in the frequency range between 100 to 1,000 Hz, and thermal control to stabilize the cavity temperature variation, dT/T, to 1 part in 107 during 100 s and to 1 part in 105 during 1 orbit.

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

    Science.gov (United States)

    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.

  4. Narrow-Band Applications of Communications Satellites.

    Science.gov (United States)

    Cowlan, Bert; Horowitz, Andrew

    This paper attempts to describe the advantages of "narrow-band" applications of communications satellites for education. It begins by discussing the general controversy surrounding the use of satellites in education, by placing the concern within the larger context of the general debate over the uses of new technologies in education, and by…

  5. Satellite Communication and Development: A Reassessment.

    Science.gov (United States)

    Hudson, Heather E.

    The potential benefits of satellite communications development have been recognized since the notion of a geostationary "space platform" was proposed by Arthur C. Clarke in 1945. Although there have been examples of developmental applications of satellite technology, the promise has been slow in being fulfilled. The history of the…

  6. Understanding satellite navigation

    CERN Document Server

    Acharya, Rajat

    2014-01-01

    This book explains the basic principles of satellite navigation technology with the bare minimum of mathematics and without complex equations. It helps you to conceptualize the underlying theory from first principles, building up your knowledge gradually using practical demonstrations and worked examples. A full range of MATLAB simulations is used to visualize concepts and solve problems, allowing you to see what happens to signals and systems with different configurations. Implementation and applications are discussed, along with some special topics such as Kalman Filter and Ionosphere. W

  7. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Fan, Shiwei; Wang, Feixue

    2016-01-01

    These Proceedings present selected research papers from CSNC2016, held during 18th-20th May in Changsha, China. The theme of CSNC2016 is Smart Sensing, Smart Perception. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2016, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  8. China Satellite Navigation Conference

    CERN Document Server

    Liu, Jingnan; Yang, Yuanxi; Fan, Shiwei; Yu, Wenxian

    2017-01-01

    These proceedings present selected research papers from CSNC2017, held during 23th-25th May in Shanghai, China. The theme of CSNC2017 is Positioning, Connecting All. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 12 topics to match the corresponding sessions in CSNC2017, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.

  9. Two Groups of Red Giants with Distinct Chemical Abundances in the Bulge Globular Cluster NGC 6553 Through the Eyes of APOGEE

    CERN Document Server

    Tang, Baitian; Geisler, Doug; Schiavon, Ricardo; Majewski, Steven R; Villanova, Sandro; Carrera, Ricardo; Zamora, Olga; Garcia-Hernandez, D A; Shetrone, Matthew; Frinchaboy, Peter; Meza, Andres; Fernández-Trincado, J G; Muñoz, Ricardo R; Lin, Chien-Cheng; Lane, Richard R; Nitschelm, Christian; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey

    2016-01-01

    Multiple populations revealed in globular clusters (GCs) are important windows to the formation and evolution of these stellar systems. The metal-rich GCs in the Galactic bulge are an indispensable part of this picture, but the high optical extinction in this region has prevented extensive research. In this work, we use the high resolution near-infrared (NIR) spectroscopic data from APOGEE to study the chemical abundances of NGC 6553, which is one of the most metal-rich bulge GCs. We identify ten red giants as cluster members using their positions, radial velocities, iron abundances, and NIR photometry. Our sample stars show a mean radial velocity of $-0.14\\pm5.47$ km s$^{-1}$, and a mean [Fe/H] of $-0.15\\pm 0.05$. We clearly separate two populations of stars in C and N in this GC for the first time. NGC 6553 is the most metal-rich GC where the multiple stellar population phenomenon is found until now. Substantial chemical variations are also found in Na, O, and Al. However, the two populations show similar S...

  10. Technology.

    Science.gov (United States)

    Online-Offline, 1998

    1998-01-01

    Focuses on technology, on advances in such areas as aeronautics, electronics, physics, the space sciences, as well as computers and the attendant progress in medicine, robotics, and artificial intelligence. Describes educational resources for elementary and middle school students, including Web sites, CD-ROMs and software, videotapes, books,…

  11. The Concept of Solar Power Satellite (SPS) and Its Key Technologies%空间太阳能电站构想及其相关技术的发展

    Institute of Scientific and Technical Information of China (English)

    张钧屏

    2011-01-01

    文章介绍了太阳功率卫星(SPS)的发展背景、基本原理和系统构成,分析了实现SPS的主要技术条件。通过分析目前国际上建设SPS所开展的实验及其相关技术的发展,以期对中国未来发展空间太阳能电站技术提供借鉴。%The developing baekgroud,concept and system structure for the solar power satellite (SPS) are described in this paper. The main specification will be discussed in detail . The SPS technology is in the frontier of the science and technology development,including advanced technologies of space, energy, power transmission and fundamental sciences on the matter and information . The key tecnologies for building SPS include the dc power generation in space,microwave power transmission, space robot technology, the infrastructure of space launch, assemble and transport.

  12. Geostationary Satellite (GOES) Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Visible and Infrared satellite imagery taken from radiometer instruments on SMS (ATS) and GOES satellites in geostationary orbit. These satellites produced...

  13. A generalized transmultiplexer and its application to mobile satellite communications

    Science.gov (United States)

    Ichiyoshi, Osamu

    A generalization of digital transmultiplexer technology is presented. The proposed method can realize transmultiplexer (TMUX) and transdemultiplexer (TDUX) filter banks whose element filters have bandwidths greater than the channel spacing frequency. This feature is useful in many communications applications. As an example, a satellite switched (SS) Frequency Division Multiple Access (FDMA) system is proposed for spot beam satellite communications, particularly for mobile satellite communications.

  14. Beyond ATS-6: Social Uses of Communications Satellites.

    Science.gov (United States)

    Cater, Douglass

    A panel discussion was held to examine the efficacy of the Applications Technology Satellites, powerful communication satellites designed to send quality signals to low-cost ground terminals. The satellites have been used on an experimental basis in rural America, Canada, and India. While the panel generally agreed on the great potential of the…

  15. Neptune's small satellites

    Science.gov (United States)

    Thomas, P.

    1992-04-01

    The small satellites of Neptune and other planets discovered during the Voyager 2 mission are discussed in terms of their composition and relationship to the planetary systems. The satellite Proteus is described in terms of its orbit, five other satellites are described, and they are compared to ther small satellites and systems. Neptune's satellites are hypothesized to be related to the ring system, and the satellite Galatea is related to the confinement of the rings.

  16. Proceedings of the Mobile Satellite Conference

    Science.gov (United States)

    Rafferty, William

    1988-01-01

    A satellite-based mobile communications system provides voice and data communications to mobile users over a vast geographic area. The technical and service characteristics of mobile satellite systems (MSSs) are presented and form an in-depth view of the current MSS status at the system and subsystem levels. Major emphasis is placed on developments, current and future, in the following critical MSS technology areas: vehicle antennas, networking, modulation and coding, speech compression, channel characterization, space segment technology and MSS experiments. Also, the mobile satellite communications needs of government agencies are addressed, as is the MSS potential to fulfill them.

  17. 卫星遥感技术在农业非点源污染评价中的应用分析%Analysis of Satellite Remote Sensing Technology in the Evaluation of Agricultural Non- point Source Pollution

    Institute of Scientific and Technical Information of China (English)

    陈强; 胡勇; 巩彩兰

    2011-01-01

    Non - point source pollution is an important source of water pollution, thus constituting one of the decisive factors affecting water environment. The commonly used agricultural non - point source pollution evaluation methods include statistical models and physical models of the computer. No matter what kind of modeling the researchers adopt, a variety of data acquisition types and the evaluation of the accuracy of the verification results make up the main bottleneck. In order to make people aware of the importance of satellite remote sensing technology in agricultural non - point source pollution evaluation, this paper made an application analysis of the access capability and feasibility of the satellite remote sensing technology from the angle of data types required by the study of the non - point source pollution, and also forecast the application potential of the satellite remote sensing technology in the precision verification of the agricultural non - point source pollution evaluation results.%非点源污染物是水污染的重要来源,已成为影响水环境状况的决定性因素之一.目前常用的农业非点源污染评价模型包括统计模型和机理模型两大类,而无论采用哪种建模方法,多类型数据的获取和评价结果的精度验证都是研究的主要瓶颈.为了使人们对卫星遥感技术在农业非点源污染评价中的应用有所了解,从非点源污染研究所需数据种类的角度,对卫星遥感技术的获取能力和可行性进行了应用分析,并对卫星遥感技术在农业非点源污染评价结果的精度验证中的应用潜力进行了展望.

  18. Technology

    Directory of Open Access Journals (Sweden)

    Xu Jing

    2016-01-01

    Full Text Available The traditional answer card reading method using OMR (Optical Mark Reader, most commonly, OMR special card special use, less versatile, high cost, aiming at the existing problems proposed a method based on pattern recognition of the answer card identification method. Using the method based on Line Segment Detector to detect the tilt of the image, the existence of tilt image rotation correction, and eventually achieve positioning and detection of answers to the answer sheet .Pattern recognition technology for automatic reading, high accuracy, detect faster

  19. Space industrialization - Education. [via communication satellites

    Science.gov (United States)

    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.

  20. Two groups of red giants with distinct chemical abundances in the bulge globular cluster NGC 6553 through the eyes of APOGEE

    Science.gov (United States)

    Tang, Baitian; Cohen, Roger E.; Geisler, Doug; Schiavon, Ricardo P.; Majewski, Steven R.; Villanova, Sandro; Carrera, Ricardo; Zamora, Olga; Garcia-Hernandez, D. A.; Shetrone, Matthew; Frinchaboy, Peter; Meza, Andres; Fernández-Trincado, J. G.; Muñoz, Ricardo R.; Lin, Chien-Cheng; Lane, Richard R.; Nitschelm, Christian; Pan, Kaike; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey

    2017-02-01

    Multiple populations revealed in globular clusters (GCs) are important windows to the formation and evolution of these stellar systems. The metal-rich GCs in the Galactic bulge are an indispensable part of this picture, but the high optical extinction in this region has prevented extensive research. In this work, we use the high-resolution near-infrared (NIR) spectroscopic data from Apache Point Observatory Galactic Evolution Experiment (APOGEE) to study the chemical abundances of NGC 6553, which is one of the most metal-rich bulge GCs. We identify 10 red giants as cluster members using their positions, radial velocities, iron abundances, and NIR photometry. Our sample stars show a mean radial velocity of -0.14 ± 5.47 km s-1, and a mean [Fe/H] of -0.15 ± 0.05. We clearly separate two populations of stars in C and N in this GC for the first time. NGC 6553 is the most metal-rich GC where the multiple stellar population phenomenon is found until now. Substantial chemical variations are also found in Na, O, and Al. However, the two populations show similar Si, Ca, and iron-peak element abundances. Therefore, we infer that the CNO, NeNa, and MgAl cycles have been activated, but the MgAl cycle is too weak to show its effect on Mg. Type Ia and Type II supernovae do not seem to have significantly polluted the second generation stars. Comparing with other GC studies, NGC 6553 shows similar chemical variations as other relatively metal-rich GCs. We also confront current GC formation theories with our results, and suggest possible avenues for improvement in the models.

  1. Performance of the Apache Point Observatory Galactic Evolution Experiment (APOGEE) high-resolution near-infrared multi-object fiber spectrograph

    Science.gov (United States)

    Wilson, John C.; Hearty, F.; Skrutskie, M. F.; Majewski, S. R.; Schiavon, R.; Eisenstein, D.; Gunn, J.; Holtzman, J.; Nidever, D.; Gillespie, B.; Weinberg, D.; Blank, B.; Henderson, C.; Smee, S.; Barkhouser, R.; Harding, A.; Hope, S.; Fitzgerald, G.; Stolberg, T.; Arns, J.; Nelson, M.; Brunner, S.; Burton, A.; Walker, E.; Lam, C.; Maseman, P.; Barr, J.; Leger, F.; Carey, L.; MacDonald, N.; Ebelke, G.; Beland, S.; Horne, T.; Young, E.; Rieke, G.; Rieke, M.; O'Brien, T.; Crane, J.; Carr, M.; Harrison, C.; Stoll, R.; Vernieri, M.; Shetrone, M.; Allende-Prieto, C.; Johnson, J.; Frinchaboy, P.; Zasowski, G.; Garcia Perez, A.; Bizyaev, D.; Cunha, K.; Smith, V. V.; Meszaros, Sz.; Zhao, B.; Hayden, M.; Chojnowski, S. D.; Andrews, B.; Loomis, C.; Owen, R.; Klaene, M.; Brinkmann, J.; Stauffer, F.; Long, D.; Jordan, W.; Holder, D.; Cope, F.; Naugle, T.; Pfaffenberger, B.; Schlegel, D.; Blanton, M.; Muna, D.; Weaver, B.; Snedden, S.; Pan, K.; Brewington, H.; Malanushenko, E.; Malanushenko, V.; Simmons, A.; Oravetz, D.; Mahadevan, S.; Halverson, S.

    2012-09-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE) uses a dedicated 300-fiber, narrow-band near-infrared (1.51-1.7 μm), high resolution (R~22,500) spectrograph to survey approximately 100,000 giant stars across the Milky Way. This three-year survey, in operation since late-summer 2011 as part of the Sloan Digital Sky Survey III (SDSS III), will revolutionize our understanding of the kinematical and chemical enrichment histories of all Galactic stellar populations. We present the performance of the instrument from its first year in operation. The instrument is housed in a separate building adjacent to the 2.5-m SDSS telescope and fed light via approximately 45-meter fiber runs from the telescope. The instrument design includes numerous innovations including a gang connector that allows simultaneous connection of all fibers with a single plug to a telescope cartridge that positions the fibers on the sky, numerous places in the fiber train in which focal ratio degradation had to be minimized, a large mosaic-VPH (290 mm x 475 mm elliptically-shaped recorded area), an f/1.4 six-element refractive camera featuring silicon and fused silica elements with diameters as large as 393 mm, three near-infrared detectors mounted in a 1 x 3 mosaic with sub-pixel translation capability, and all of these components housed within a custom, LN2-cooled, stainless steel vacuum cryostat with dimensions 1.4-m x 2.3-m x 1.3-m.

  2. Small satellites and their regulation

    CERN Document Server

    Jakhu, Ram S

    2014-01-01

    Since the launch of UoSat-1 of the University of Surrey (United Kingdom) in 1981, small satellites proved regularly to be useful, beneficial, and cost-effective tools. Typical tasks cover education and workforce development, technology demonstration, verification and validation, scientific and engineering research as well as commercial applications. Today the launch masses range over almost three orders of magnitude starting at less than a kilogram up to a few hundred kilograms, with budgets of less than US$ 100.00 and up to millions within very short timeframes of sometimes less than two years. Therefore each category of small satellites provides specific challenges in design, development and operations. Small satellites offer great potentials to gain responsive, low-cost access to space within a short timeframe for institutions, companies, regions and countries beyond the traditional big players in the space arena. For these reasons (particularly the low cost of construction, launch and operation), small (m...

  3. 基于DVB-RCS的VSAT宽带卫星通信技术与应用%VSAT Broadband Satellite Communications Technology Based on DVB-RCS and its Applications

    Institute of Scientific and Technical Information of China (English)

    郅琦

    2011-01-01

    This paper describes the principles of VSAT data networks,satellite communication systems and the development trend of the broadband DVB-RCS open standard.Through the introduction of VSAT DVB-RCS based broadband satellite communication system in an engineering application examples,including system operations and characteristics,and the basic configuration of the subsystem,it can be concluded that along with broadband networks and services,VSAT satellite communication systems are transforming from the narrowband to broadband system.In the existing technology,based on DVB-RCS standard which has the advantages of openness and low cost,the VSAT broadband satellite communications system will have broad market prospects,especially in the vast remote rural areas.It will be one of the major solutions to the communication problem of the rural areas.%介绍了VSAT数据网原理、卫星通信系统宽带化的发展趋势及DVB-RCS开放标准。通过介绍基于DVB-RCS的VSAT宽带卫星通信系统在工程中的应用实例,其中包括系统业务与特点,以及各子系统的基本配置等,可以得出,随着网络和业务的宽带化,VSAT卫星通信系统正在从传统的窄带向宽带系统转变。在现有技术中,基于DVB-RCS标准因其开放性和较高性价比,在VSAT宽带卫星通信系统中的应用将具有广泛的市场前景,尤其在广大偏远农村地区,将成为解决我国农村通信问题的主要手段之一。

  4. Space Power for Communication Satellites Beyond 1995

    Science.gov (United States)

    Pierce, P. R.

    1984-01-01

    The space power trends for communication satellites beginning in the mid-70's are reviewed. Predictions of technology advancements and requirements were compared with actual growth patterns. The conclusions derived suggest that the spacecraft power system technology base and present rate of advancement will not be able to meet the power demands of the early to mid-90's. It is recommended that an emphasis on accelerating the technology development be made to minimize the technology gap.

  5. Chartering Launchers for Small Satellites

    Science.gov (United States)

    Hernandez, Daniel

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

  6. Satellite data compression

    CERN Document Server

    Huang, Bormin

    2011-01-01

    Satellite Data Compression covers recent progress in compression techniques for multispectral, hyperspectral and ultra spectral data. A survey of recent advances in the fields of satellite communications, remote sensing and geographical information systems is included. Satellite Data Compression, contributed by leaders in this field, is the first book available on satellite data compression. It covers onboard compression methodology and hardware developments in several space agencies. Case studies are presented on recent advances in satellite data compression techniques via various prediction-

  7. Trends in communications satellites

    CERN Document Server

    Curtin, Denis J

    1979-01-01

    Trends in Communications Satellites offers a comprehensive look at trends and advances in satellite communications, including experimental ones such as NASA satellites and those jointly developed by France and Germany. The economic aspects of communications satellites are also examined. This book consists of 16 chapters and begins with a discussion on the fundamentals of electrical communications and their application to space communications, including spacecraft, earth stations, and orbit and wavelength utilization. The next section demonstrates how successful commercial satellite communicati

  8. Advanced ISDN satellite designs and experiments

    Science.gov (United States)

    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.

  9. Geostationary Operational Environmental Satellite (GOES)-8 mission flight experience

    Science.gov (United States)

    Noonan, C. H.; McIntosh, R. J.; Rowe, J. N.; Defazio, R. L.; Galal, K. F.

    1995-05-01

    The Geostationary Operational Environmental Satellite (GOES)-8 spacecraft was launched on April 13, 1994, at 06:04:02 coordinated universal time (UTC), with separation from the Atlas-Centaur launch vehicle occurring at 06:33:05 UTC. The launch was followed by a series of complex, intense operations to maneuver the spacecraft into its geosynchronous mission orbit. The Flight Dynamics Facility (FDF) of the Goddard Space Flight Center (GSFC) Flight Dynamics Division (FDD) was responsible for GOES-8 attitude, orbit maneuver, orbit determination, and station acquisition support during the ascent phase. This paper summarizes the efforts of the FDF support teams and highlights some of the unique challenges the launch team faced during critical GOES-8 mission support. FDF operations experience discussed includes: (1) The abort of apogee maneuver firing-1 (AMF-1), cancellation of AMF-3, and the subsequent replans of the maneuver profile; (2) The unexpectedly large temperature dependence of the digital integrating rate assembly (DIRA) and its effect on GOES-8 attitude targeting in support of perigee raising maneuvers; (3) The significant effect of attitude control thrusting on GOES-8 orbit determination solutions; (4) Adjustment of the trim tab to minimize torque due to solar radiation pressure; and (5) Postlaunch analysis performed to estimate the GOES-8 separation attitude. The paper also discusses some key FDF GOES-8 lessons learned to be considered for the GOES-J launch which is currently scheduled for May 19, 1995.

  10. The power relay satellite

    Science.gov (United States)

    Glaser, Peter E.

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

  11. The Galilean Satellites

    Science.gov (United States)

    1998-01-01

    This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. Shown from left to right in order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto.The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity.North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element.The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft acquired the Io and Ganymede images in June 1996, the Europa images in September 1996, and the Callisto images in November 1997.Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission

  12. Secure voice for mobile satellite applications

    Science.gov (United States)

    Vaisnys, Arvydas; Berner, Jeff

    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.

  13. Secure voice for mobile satellite applications

    Science.gov (United States)

    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.

  14. 卫星电源控制中霍尔非接触测量技术%Hall noncontact measure technology in control of satellites power

    Institute of Scientific and Technical Information of China (English)

    曲鹏; 罗顺; 贾文涛

    2009-01-01

    1879年,美国物理学家爱德华·海博特·霍尔发现霍尔效应以来.霍尔技术越来越多地应用于工业控制的各个领域,特别是随着二十世纪中叶第三次产业革命产生的科学技术大爆发.使得基于霍尔效应原理研制而成的霍尔电流传感器.彻底改变了工业应用中对电压、电流的测量方法.霍尔电流传感器是一种新型磁敏传感器,介绍霍尔电流传感器的使用原理,及在卫星电源控制器中应用的典型霍尔电流传感器基本技术条件和在小卫星中对整星方阵电流、负载电流、放电电流的测量举例.%Since an American physical scientist Hay Bode Edward Hall discovered Hall Effect in 1879, technique of Hall has been used in a growing number of industrial fields. Especially with the third industry revolution breaking out in the middle of 20th, Hall current sensor as a new type of magnetic sensor developed based on the principle of Hall Effect has totally changed the ways of measuring current and voltage in the industrial application. The theory of Hall sensor and the basic technical conditions of typical Hall current sensor applied in satellite power controller were introduced in this article, and some examples of whole square current, load current and discharge current in moonlet have been given.

  15. Xichang Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    Xichang Satellite Launch Center(XSLC) is mainly for geosynchronous orbit launches. The main purpose of XSLC is to launch spacecraft, such as broadcasting,communications and meteorological satellites, into geo-stationary orbit.Most of the commercial satellite launches of Long March vehicles have been from Xichang Satellite Launch Center. With 20 years' development,XSLC can launch 5 kinds of launch vehicles and send satellites into geostationary orbit and polar orbit. In the future, moon exploration satellites will also be launched from XSLC.

  16. Simulator design for advanced ISDN satellite design and experiments

    Science.gov (United States)

    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.

  17. Thermal deformations of a glass spherical satellite

    Science.gov (United States)

    Vasiliev, V. P.; Nenadovich, V. D.; Murashkin, V. V.; Sokolov, A. L.

    2016-09-01

    The effect of the kind of the reflecting coating of a glass spherical satellite on thermal deformations caused by the solar irradiation is considered. Two types of coating deposited on one of the hemispheres are considered: aluminum with a protective layer of bakelite varnish and interference dielectric coating for two orientations of the satellite orbit. Structures of a multilayer dielectric coating and technologies of its deposition are described.

  18. Hydrogen Peroxide Propulsion for Smaller Satellites

    OpenAIRE

    Whitehead, John

    1998-01-01

    As satellite designs shrink, providing maneuvering and control capability falls outside the realm of available propulsion technology. While cold gas has been used on the smallest satellites, hydrogen peroxide propellant is suggested as the next step in performance and cost before hydrazine. Minimal toxicity and a small scale enable bench top propellant preparation and development testing. Progress toward low-cost thrusters and self-pressurizing tank systems is described.

  19. MEMOS - Mars Environment Monitoring Satellite

    Science.gov (United States)

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

    2007-08-01

    The Swedish Institute of Space Physics (IRF) in cooperation with the Swedish Space Corporation (SSC) has conducted first studies on a Mars Environment Monitoring Satellite (MEMOS). The MEMOS microsatellite (mass ELT) Proximity-1 transceiver will autonomously communicate with the parent satellite at inter-satellite ranges 2 kbit/s. The transceiver also implements a coherent transponding mode for orbit determination through two-way Doppler ranging between the parent satellite and MEMOS. In addition ELT is compatible with a future Martian communication and navigation network pursued by NASA, which could be taken advantage of in the future for relaying data or performing ranging via other satellites part of the network. A system design driver for inter-satellite communication at Mars is the high demand of power. This leads to a disk-shape and thus easy to accommodate spacecraft configuration of MEMOS comprising a single sun-pointing solar array favourable in terms of power and spin stability. Multi-junction solar cells, which currently have an efficiency of ~29% under laboratory conditions are a key factor to keep MEMOS solar array area of ~1.15 m2 small compared to the worst case system power requirements of ~105 W. During eclipse periods high-efficient Li-ion batteries (6 x 20 Wh) will ensure power supply. The spacecraft and payload design will incorporate new technology developments such as autonomous navigation, MicroElectroMechanical Systems MEMS, Micro- Opto-ElectroMechanical Systems MOEMS and new materials to achieve low mass at high performance. Thereby it will profit from Swedish developments and heritage in small- / microsatellites like Astrid-2, SMART-1 or the upcoming rendezvous and formation flying demonstration mission PRISMA.

  20. Satellite Communication and Long Distance Education

    Directory of Open Access Journals (Sweden)

    Hafied Cangara

    2016-02-01

    Full Text Available Since Indonesia introduced communication satellite for telecommunication network, the satellite has brought a number of advantages for national development in various areas, such as telephone network, mass media development, business, education, politics, security and national defence as well as regional and international cooperation. In education, satellite communication could be used for long-distance learning as implemented by 13 state universities in eastern parts of Indonesia. It is also possible to develop the Open University System in teaching and learning process, particularly since the internet technology has been intensively used

  1. Technical developments in international satellite business services

    Science.gov (United States)

    Tan, P. P.

    At the conception of International Satellite Business Services (ISBS), it was a primary objective to provide flexibility for accommodating a variety of service requirements which might be established by mutual agreement between users. The design guidelines are to ensure that the space segment is efficiently utilized, while other satellite services are protected from interference. Other considerations are related to an acceptable earth segment cost, maximum connectivity in worldwide services, the capability of growth and a reasonably smooth transition into future systems, and the maintenance of high performance objectives. Attention is given to a system overview, the characteristics of satellites for ISBS, and technological developments with some application possibilities for ISBS.

  2. Advanced tracking and data relay satellite system

    Science.gov (United States)

    Stern, Daniel

    1992-01-01

    The purpose of this communication satellite system are as follows: to provide NASA needs for satellite tracking and communications through the year 2012; to maintain and augment the current TDRS system when available satellite resources are expended in the latter part of the decade; to provide the necessary ground upgrade to support the augmented services; and to introduce new technology to reduce the system life cycle cost. It is concluded that no ATDRS spacecraft requirement for new modulation techniques, that data rate of 650 MBps is required, and that Space Station Freedom requirement is for 650 MBps data some time after the year 2000.

  3. Galileo satellite antenna modeling

    Science.gov (United States)

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

    2015-04-01

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

  4. Communications technology

    Science.gov (United States)

    Cuccia, C. Louis; Sivo, Joseph

    1986-01-01

    The technologies for optimized, i.e., state of the art, operation of satellite-based communications systems are surveyed. Features of spaceborne active repeater systems, low-noise signal amplifiers, power amplifiers, and high frequency switches are described. Design features and capabilities of various satellite antenna systems are discussed, including multiple beam, shaped reflector shaped beam, offset reflector multiple beam, and mm-wave and laser antenna systems. Attitude control systems used with the antenna systems are explored, along with multiplexers, filters, and power generation, conditioning and amplification systems. The operational significance and techniques for exploiting channel bandwidth, baseband and modulation technologies are described. Finally, interconnectivity among communications satellites by means of RF and laser links is examined, as are the roles to be played by the Space Station and future large space antenna systems.

  5. Satellite-Delivered Learning.

    Science.gov (United States)

    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)

  6. GPS Satellite Simulation Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The GPS satellite simulation facility consists of a GPS satellite simulator controlled by either a Silicon Graphics Origin 2000 or PC depending upon unit under test...

  7. China's Recoverable Satellites

    Institute of Scientific and Technical Information of China (English)

    Tang Boehang

    2008-01-01

    @@ By the end of 2006, China had launched 24 recoverable satellites (FSW) in total. Among them, 23 were launched successfully, of which all but one were successfully recovered. Recoverable satellites launched by China are listed in Table 1.

  8. Satellite Tags- Hawaii EEZ

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Satellite tagging was implemented in 2013. Satellite tagging is conducted using a Dan Inject air rifle and deployment arrows designed by Wildlife Computers. Two...

  9. GOES-R: Satellite Insight

    Science.gov (United States)

    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.

  10. Taiyuan Satellite Launch Center

    Institute of Scientific and Technical Information of China (English)

    LiuJie

    2004-01-01

    There are three major space launch bases in China, the Jiuquan Satellite Launch Center,the Taiyuan Satellite Launch Center and the Xichang Satellite Launch Center. All the three launch centers are located in sparsely populated areas where the terrain is even and the field of vision is broad. Security, transport conditions and the influence of the axial rotation

  11. Geodetic Secor Satellite

    Science.gov (United States)

    1974-06-01

    simple, and had low-power lem. 17 14. Satellite Orientation . The satellite was designed to maintain a constant relationship between the antenna...the same satellite orientation . Further considerations were Th oscillations, however, when higher orbital ranges (500-2500 nautical miles) -, 3 a

  12. TC-2 Satellite Delivered

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    On April 18, 2005, TC-2, the second satellite of Double Star Program (DSP), which was jointly developed by CNSA and ESA, was approved to be delivered to the user after the on-board test and trial operation. The satellite is working well and the performance can meet the user's need. The satellite has collected large amount of valuable scientific data

  13. Magnetic Bearings for Small Satellite CMG's and Other Miniature Spacecraft Mechanisms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA sees an increasing role in the near future for small satellites in the 5-100 kg size range. A potentially disruptive technology, small satellites, which are low...

  14. Quick searching technology for satellite DVB-S/S2 carriers%星上DVB-S2载波快速搜索技术

    Institute of Scientific and Technical Information of China (English)

    吴慧谦; 黄焱; 张白愚

    2012-01-01

    New features and development status of Digital Video Broadcasting(DVB)-S2 are analyzed compared to DVB-S. This paper proposes a novel search program of the DVB-S2 signal reception parameters based on TDQR-C005F, focusing on the search technologies of carrier center frequency and bandwidth parameters about the broadband signals, and three-step search technology and implementation of the algorithm concerning parameters of the signal channel including symbol rate, coding rate and pilot frequency. The algorithms and systems can meet the detection and identification requirements of the DVB-S2 burst signal compared to traditional algorithms. Experiments show that, the system can lock those conventional DVB-S/S2 signals accurately except for DVB signals whose bandwidth is below 2 MHz, reaching the search rate of 97.5%.%分析数字视频广播(DVB)-S2相对DVB-S的新特性和发展现状,提出一种基于TDQR-C005F的DVB-S/S2载波信号接收参数的搜索方案.重点针对宽带信号载波的中心频率和带宽参数的搜索技术,以及信号频道的符码率、编码码率和导频参数的三级搜索技术进行分析研究.与传统算法相比,算法和系统快速有效地解决了对DVB-S/S2突发信号的检测识别.实验表明,除对极少带宽小于2 MHz的DVB信号难以锁定外,系统对其他常规DVB-S/S2信号实现了准确锁定,识别搜索率达到97.5%.

  15. SmallSats, Iodine Propulsion Technology, Applications to Low-Cost Lunar Missions, and the Iodine Satellite (iSAT) Project

    Science.gov (United States)

    Dankanich, John W.

    2014-01-01

    Closing Remarks: ?(1) SmallSats hold significant potential for future low cost high value missions; (2) Propulsion remains a key limiting capability for SmallSats that Iodine can address: High ISP * Density for volume constrained spacecraft; Indefinite quiescence, unpressurized and non-hazardous as a secondary payload; (3) Iodine enables MicroSat and SmallSat maneuverability: Enables transfer into high value orbits, constellation deployment and deorbit; (4) Iodine may enable a new class of planetary and exploration class missions: Enables GTO launched secondary spacecraft to transit to the moon, asteroids, and other interplanetary destinations for approximately 150 million dollars full life cycle cost including the launch; (5) ESPA based OTVs are also volume constrained and a shift from xenon to iodine can significantly increase the transfer vehicle change in volume capability including transfers from GTO to a range of Lunar Orbits; (6) The iSAT project is a fast pace high value iodine Hall technology demonstration mission: Partnership with NASA GRC and NASA MSFC with industry partner - Busek; (7) The iSAT mission is an approved project with PDR in November of 2014 and is targeting a flight opportunity in FY17.

  16. Satellite broadcasting - The European experience and perspective

    Science.gov (United States)

    Watson, Alan

    1991-11-01

    The use of satellites is considered as a means for developing a European transnational broadcasting system with attention given to the control of technology. A tension is described between maintaining technology as the property of one nation when the DBSs are developed for multinational program broadcasting. The simultaneous development of satellite systems is theorized to lead eventually to a single merged program for a particular nation, and the effect is considered of the regulation of cross-holding and cross-selling systems by investors.

  17. Theory of geostationary satellites

    CERN Document Server

    Zee, Chong-Hung

    1989-01-01

    Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

  18. Educational Benefits From the AAU-cubesat Student Satellite Project

    DEFF Research Database (Denmark)

    Alminde, Lars

    2003-01-01

    In September 2001 Aalborg university started the AAU-cubesat project that reached it climax when the student built satellite was launched into space on the 30th of June 2003 on top of a former Russian ICBM. AAU-cubesat was among the first five satellites to be launched that are built within...... the cubesat concept that prescribes a satellite with dimensions 10x10x10cm and mass one kilogram. These constraints clearly limits the possibilities for the satellite in terms of possible scientific missions, but on the other hand: by building satellites of this size a technology push is created...... that in the future will help to reduce the size of both scientific and commercial satellites and thus help to drive down the launch cost. This paper will describe the overall architecture of the AAU-cubesat. Results from the operation phase will be stated, and recommendations on further work on pico-satellite...

  19. Instrument technology for magnetosphere plasma imaging from high Earth orbit. Design of a radio plasma sounder

    Science.gov (United States)

    Haines, D. Mark; Reinisch, Bodo W.

    1995-01-01

    The use of radio sounding techniques for the study of the ionospheric plasma dates back to G. Briet and M. A. Tuve in 1926. Ground based swept frequency sounders can monitor the electron number density (N(sub e)) as a function of height (the N(sub e) profile). These early instruments evolved into a global network that produced high-resolution displays of echo time delay vs frequency on 35-mm film. These instruments provided the foundation for the success of the International Geophysical Year (1958). The Alouette and International Satellites for Ionospheric Studies (ISIS) programs pioneered the used of spaceborne, swept frequency sounders to obtain N(sub e) profiles of the topside of the ionosphere, from a position above the electron density maximum. Repeated measurements during the orbit produced an orbital plane contour which routinely provided density measurements to within 10%. The Alouette/ISIS experience also showed that even with a high powered transmitter (compared to the low power sounder possible today) a radio sounder can be compatible with other imaging instruments on the same satellite. Digital technology was used on later spacecraft developed by the Japanese (the EXOS C and D) and the Soviets (Intercosmos 19 and Cosmos 1809). However, a full coherent pulse compression and spectral integrating capability, such as exist today for ground-based sounders (Reinisch et al., 1992), has never been put into space. NASA's 1990 Space Physics Strategy Implementation Study "The NASA Space Physics Program from 1995 to 2010" suggested using radio sounders to study the plasmasphere and the magnetopause and its boundary layers (Green and Fung, 1993). Both the magnetopause and plasmasphere, as well as the cusp and boundary layers, can be observed by a radio sounder in a high-inclination polar orbit with an apogee greater than 6 R(sub e) (Reiff et al., 1994; Calvert et al., 1995). Magnetospheric radio sounding from space will provide remote density measurements of

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

    Science.gov (United States)

    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.

  1. ENGINEERING CONTRACT ON FY-2 BATCH 2 SATELLITES SIGNED

    Institute of Scientific and Technical Information of China (English)

    SunQing

    2004-01-01

    The signing ceremony of the Engineering Contract on FY-2 Batch 2 (FY-2 02) Satellites was held in Beijing by Commission of Science, Technology and Industry for National Defense (COSTIND) on August 31, 2004. The contract on the development and manufacture of FY-2 batch 2 satellites and the contract on the launch, test and control of FY-2 Batch 2 satellites were signed by China Meteorological Administration (CMA),

  2. History of Satellite TV Broadcasting and Satellite Broadcasting Market in Turkey

    Directory of Open Access Journals (Sweden)

    Mihalis KUYUCU

    2015-09-01

    Full Text Available The present study analyses the satellite broadcasting that is the first important development that emerged as a result of digitalization in communication technologies and its reflections in Turkey. As the first milestone in the globalization of television broadcasting, satellite broadcasting provided substantial contribution towards the development of the media. Satellite bro adcasting both increased the broadcasting quality and geographical coverage of the television media. A conceptual study was carried out in the first part of the study in connection with the history of satellite broadcasting in Turkey and across the world. In the research part of the study, an analysis was performed on 160 television channels that broadcast in Turkey via Turksat Satellite. Economic structure of the television channels broadcasting in Turkey via satellite was studied and an analysis was perfo rmed on the operational structure of the channels. As a result of the study, it was emphasized that the television channels broadcasting via satellite platform also use other platforms for the purpose of spreading their broadcasts and television channel ow ners make investments in different branches of the media, too. Capital owners invest in different business areas other than the media although television channels broadcasting via Turksat mostly focus on thematic broadcasting and make effort to generate ec onomic income from advertisements. Delays are encountered in the course of the convergence between the new media and television channels that broadcast only from the satellite platform and such television channels experience more economic problems than the other channels. New media and many TV broadcasting platforms emerged as a result of the developments in the communication technologies. In television broadcasting, satellite platform is not an effective platform on its own. Channels make effort to reach t o more people by using other platforms in addition to

  3. Fluxes of energetic protons and electrons measured on board the Oersted satellite

    Directory of Open Access Journals (Sweden)

    J. Cabrera

    2005-11-01

    Full Text Available The Charged Particle Detector (CPD on board the Oersted satellite (649 km perigee, 865 km apogee and 96.48° inclination currently measures energetic protons and electrons. The measured peak fluxes of E>1 MeV electrons are found to confirm the predictions of AE8-MAX, though they occur at a geographical position relatively shifted in the SAA. The fluxes of protons are one order of magnitude higher than the predictions of AP8-MAX in the energy range 20-500 MeV. This huge discrepancy between AP8 and recent measurements in LEO was already noticed and modelled in SAMPEX/PSB97 and TPM-1 models. Nevertheless some other LEO measurements such as PROBA and CORONA-F result in flux values in good agreement with AP8 within a factor 2. The anisotropy of the low-altitude proton flux, combined with measurement performed on board three-axis stabilised satellites, has been suspected to be one possible source of the important discrepancies observed by different missions. In this paper, we evaluate the effect of anisotropy on flux measurements conducted using the CPD instruments. On the basis of the available data, we confirm the inaccuracy of AP8 at LEO and suggest methods to improve the analysis of data in future flux measurements of energetic protons at low altitudes.

  4. Communication satellites to enter a new age of flexibility

    Science.gov (United States)

    Balty, Cédric; Gayrard, Jean-Didier; Agnieray, Patrick

    2009-07-01

    To cope with the economical and technical evolutions of the communication market and to better compete with or complement terrestrial networks, satellite operators are requiring more flexible satellites. It allows a better fleet planning potential and back-up policy, a more standardized and efficient procurement process, mission adaptation to market evolution and the possibility of early entry in new markets. New technologies that are developed either for terrestrial networks or for space defense applications would become soon available to satellite and equipment manufacturers. A skilful mix of these new technologies with the older and more mature ones should boost satellite performances and bring flexibility to the new generation of communication satellites. This paper reviews the economical and technical environment of the space communication business for the next decade. It identifies the needs and levels of flexibility that are required by the market but also allowed by technologies, in both a top-down and bottom-up approach.

  5. Technical comparison of several global mobile satellite communications systems

    Science.gov (United States)

    Comparetto, Gary M.

    The era of satellite-based mobile satellite communications (MSC) systems started with the first MARISAT satellite which was launched into a geostationary orbit over the Pacific Ocean in 1976 to provide communications between ships and shore stations. The combination of high cost and unacceptably large equipment has kept the space-based MSC systems from appealing to the wider market of personal mobile communications. The progress made over the last ten years, however, in digital voice processing, satellite technology, and component miniaturization has resulted in the viability of satellite-based mobile satellite communications systems to meet the growing market in personal mobile communications using handsets similar to those currently in use with land-based cellular systems. Three of the more mature LEO/MEO satellite systems are addressed in this paper including GLOBALSTAR, Iridium, and Odyssey. The system architectures of each system are presented along with a description of the satellite and user handset designs and the multiaccess techniques employed. It will be shown that, although a number of similarities exist among the system addressed, each system is unique in a variety of significant design areas. It is concluded that the technical feasibility of satellite-based mobile satellite communications systems seems to be secure. It will be challenging, however, for the vendors to actually develop and deploy these systems in a cost effective, timely, and reliable way that meets a continually evolving set of requirements based upon a rapidly changing technology base.

  6. An Overview Of Operational Satellites Built By China:Communications Satellites (Part 2)

    Institute of Scientific and Technical Information of China (English)

    Zong He

    2009-01-01

    @@ INNOVATIVE GENERATION: THE DFH-4 PLATFORM AND SATELLITES The DFH-4 platform is the third generation of China-built large geostationary satellite platform with large output power,payload capacity and long service lifetime.Its overall performance ranks with other international advanced satellite platforms.This platform can be used for many services such as high capacity broadcast communication,direct TV broadcasting,digital audio broadcasting and broadband multimedia,which are badly needed for national economic construction and markets both at home and abroad.The platform also has effective technologies that can ensure the security of information transmission.

  7. Satellite Meteorology Education & Training Resources from COMET

    Science.gov (United States)

    Abshire, W. E.; Dills, P. N.; Weingroff, M.; Lee, T. F.

    2012-12-01

    The COMET® Program (www.comet.ucar.edu) receives funding from NOAA NESDIS as well as EUMETSAT and the Meteorological Service of Canada to support education and training in satellite meteorology. These partnerships enable COMET to create educational materials of global interest on geostationary and polar-orbiting remote sensing platforms. These materials focus on the capabilities and applications of current and next-generation satellites and their relevance to operational forecasters and other user communities. By partnering with experts from the Naval Research Laboratory, NOAA-NESDIS and its Cooperative Institutes, Meteorological Service of Canada, EUMETSAT, and other user communities, COMET stimulates greater use of satellite data observations and products. This presentation provides an overview of COMET's recent satellite education efforts in the area of polar orbiting satellites. COMET has a new module on Suomi NPP, which describes the satellite system and discusses the improvements that it is bringing to forecasting, numerical weather prediction, and environmental monitoring. COMET has also published an updated version of its module on the VIIRS instrument. "Imaging with VIIRS: A Convergence of Technologies and Experience, 2nd Edition" covers the instrument's enhanced capabilities by examining the systems that contributed to its development. Special attention is paid to the Day/Night Visible channel as VIIRS is the first instrument on a civilian satellite to image atmospheric and terrestrial features with and without moonlight. An upcoming module will exclusively focus on nighttime imaging with the VIIRS Day/Night Band (DNB). "Applications of the VIIRS Day-Night Band" will introduce the capabilities of DNB imagery to a wide audience ranging from forecasters and emergency managers to wildfire fighters and oceanographers. DNB products will be compared to traditional satellite products made from infrared data, including the "fog" product. Users will learn how DNB

  8. Methods of satellite oceanography

    Science.gov (United States)

    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.

  9. Trends in NASA communication satellites.

    Science.gov (United States)

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

    1972-01-01

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

  10. Newnes communications technology handbook

    CERN Document Server

    Lewis, Geoff

    1994-01-01

    Newnes Communications Technology Handbook provides a discussion on different topics relevant to communications technology. The book is comprised of 39 chapters that tackle a wide variety of concern in communications technology. The coverage of the text includes technologies, such as analog digital communications systems, radio frequency receiver, and satellite systems. The book also discusses some methods and techniques used in communications technology, including mixer signal processing, modulation and demodulation, and spread spectrum techniques. The text will be of great use to engineers, t

  11. Recent Korean R&D in Satellite Communications

    Science.gov (United States)

    Lee, Ho-Jin; Kim, Jae Moung; Lee, Byung-Seub; Lee, Han; Ryoo, Jang-Soo

    The R&D in satellite communications in Korea has been driven mainly by KCC (Korea Communications Commission) but in a small scale compared to Korea space development program organized by MEST (Ministry of Education, Science and Technology). Public and civilian satcom sector R&D has been led mainly by ETRI with small/medium companies contrary to rare investment in private sector while military sector R&D has been orchestrated by ADD with defense industry. By the COMS (Communication, Ocean and Meteorological Satellite) experimental Ka-band payload, Korea pursues a space qualification of own technology for national infrastructure evolution as well as industrialization of space R&D results. Once COMS launched and space qualified in 2009, subsequent application experiments and new technology R&D like UHDTV will entail service and industry promotion. The payload technology is expected for the next Korean commercial satellites or for new OBP satellites. The COMS ground control system and GNSS ground station technologies are under development for COMS operation and enhanced GNSS services along with advent of Galileo respectively. Satellite broadband mobile VSAT based on DVB-S2/RCS (+M) and low profile tracking antennas have been developed for trains, ships, and planes. While APSI is developing GMR-1 based Thuraya handset functions, ETRI is designing IMT-Advanced satellite radio interface for satellite and terrestrial dual-mode handheld communication system like Japanese STICS, with universities' satellite OFDM researches. A 21GHz Ka-band higher-availability scalable HD broadcasting technology and SkyLife's hybrid satellite IPTV technology are being developed. In near term Korea will extend R&D programs to upgrade the space communication infrastructure for universal access to digital opportunity and safer daily life from disaster, and to promote space green IT industrialization, national security, and space resources sovereign. Japanese stakeholders are invited to establish

  12. A decentralized design philosophy for satellites

    DEFF Research Database (Denmark)

    Nielsen, Jens Frederik Dalsgaard; Larsen, Jesper Abildgaard

    2011-01-01

    For the last decade development and construction of student cubesat satellites has played an important part in the engineering Master Program within Electrical Engineering and Information Technology at Aalborg University, Denmark. As a result three cubesats AAU CUBESAT, AAUSAT-II and AAUSAT3 has...

  13. The Proba Satellite Star Tracker Performance

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Denver, Troelz; Betto, Maurizio

    2005-01-01

    ESA's PROBA satellite features a high degree of autonomy, both technologically and scientifically. It is build around a powerful command, data and AOCS controller and with its less than 100 kg it is a true microsatellite. The scientific mission of PROBA includes a scanning telescope, which calls ...

  14. A decentralized design philosophy for satellites

    DEFF Research Database (Denmark)

    Nielsen, Jens Frederik Dalsgaard; Larsen, Jesper Abildgaard

    2011-01-01

    For the last decade development and construction of student cubesat satellites has played an important part in the engineering Master Program within Electrical Engineering and Information Technology at Aalborg University, Denmark. As a result three cubesats AAU CUBESAT, AAUSAT-II and AAUSAT3 has...

  15. Cultural Effects and Uses of Communication Satellites.

    Science.gov (United States)

    Schramm, Wilbur

    The communication satellite already has developed a mature technology. It carries a substantial part of the world's long range communication, and is now useable for special cultural and educational purposes. Major cultural effects come from its contribution to increasing enormously the flow of information in the world. It will increase human…

  16. Satellite Attitude Control Using Atmospheric Drag

    Science.gov (United States)

    2007-03-01

    Astronautics Graduate School of Engineering and Management Air Force Institute of Technology Air University Air Education and Training Command In...yaw axes and provide magnetic damping on both the pitch and yaw axes. The satellite resem- bles a shuttlecock used in badminton (see Figure 2.2). The...Control Using Atmospheric Drag Guettler, David B., Captain, USAF Air Force Institute of Technology Graduate School of Engineering and Management (AFIT

  17. Using satellite imagery for crime mapping in South Africa.

    CSIR Research Space (South Africa)

    Schmitz, Peter MU

    2002-12-01

    Full Text Available . Increasingly, technologies such as digital orthophotographs, high-resolution satellite imagery and the global positioning system (GPS) are being used for these areas to provide base mapping and application data for geographical information systems (GIS...

  18. Satellites of spiral galaxies

    Science.gov (United States)

    Zaritsky, Dennis; Smith, Rodney; Frenk, Carlos; White, Simon D. M.

    1993-01-01

    We present a survey of satellites around a homogeneous set of late-type spirals with luminosity similar to that of the Milky Way. On average, we find fewer than 1.5 satellites per primary, but we argue that we can treat the survey as an ensemble and so derive the properties of the halo of a 'typical' isolated spiral. The projected density profile of the ensemble falls off approximately as 1/r. Within 50 kpc the azimuthal distribution of satellites shows some evidence for the 'Holmberg effect', an excess near the minor axis of the primary; however, at larger projected distances, the distribution appears isotropic. There is a weak but significant correlation between the size of a satellite and its distance from its primary, as expected if satellites are tidally truncated. Neither Hubble type nor spectral characteristics correlate with apparent separation. The ensemble of satellites appears to be rotating at about 30 km/s in the same direction as the galactic disk. Satellites on prograde orbits tend to be brighter than those on retrograde orbits. The typical velocity difference between a satellite and its primary shows no clear dependence either on apparent separation, or on the rotation speed of the primary. Thus our survey demonstrates that isolated spiral galaxies have massive halos that extend to many optical radii.

  19. Teamwork Reasoning and Multi-Satellite Missions

    Science.gov (United States)

    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.

  20. Engineering Test Satellite VI (ETS-VI)

    Science.gov (United States)

    Horii, M.; Funakawa, K.

    1991-01-01

    The Engineering Test Satellite-VI (ETS-VI) is being developed as the third Japanese three-axis stabilized engineering test satellite to establish the 2-ton geostationary operational satellite bus system and to demonstrate the high performance satellite communication technology for future operational satellites. The satellite is expected to be stationed at 154 deg east latitude. It will be launched from the Tanegashima Space Center in Japan by a type H-II launch vehicle. The Deep Space Network (DSN) will support the prelaunch compatibility test, data interface verification testing, and launch rehersals. The DSN primary support period is from launch through the final AEF plus 1 hour. Contingency support is from final AEF plus 1 hour until launch plus 1 month. The coverage will consist of all the 26-m antennas as prime and the 34-m antennas at Madrid and Canberra as backup. Maximum support will consist of two 8-hour tracks per station for a 7-day period, plus the contingency support, if required. Information is given in tabular form for DSN support, telemetry, command, and tracking support responsibility.

  1. Defense Weather Satellites: DOD Faces Acquisition Challenges for Addressing Capability Needs

    Science.gov (United States)

    2016-07-07

    design . Our work on the NPOESS program has shown that without clear lines of authority, conflicts between satellite users hampered decisions, such as for...DEFENSE WEATHER SATELLITES DOD Faces Acquisition Challenges for Addressing Capability Needs Statement of Cristina T...Environment, Committee on Science, Space, and Technology, House of Representatives July 2016 DEFENSE WEATHER SATELLITES DOD Faces Acquisition

  2. A Time and Space-based Dynamic IP Routing in Broadband Satellite Networks

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The topology architecture, characteristics and routing technologies of broadband satellite networks are studied in this paper. The authors propose the routing scheme of satellite networks and design a time and space-based distributed routing algorithm whose complexity is O(1). Simulation results aiming at satellite mobility show that the new algorithm can determine the minimum propagation delay paths effectively.

  3. A Model To Address Design Constraints of Training Delivered via Satellite. Study Number Eight.

    Science.gov (United States)

    Montler, Joseph; Geroy, Gary D.

    This document: summarizes how some companies are addressing the design constraints involved in using satellite technology to deliver training, presents a model aimed at examining cost effectiveness of the satellite option, and includes a guide to designing instructional materials for delivery by satellite. A survey of 39 organizations, 12…

  4. Systematic identification of applications for a cluster of femto-satellites

    NARCIS (Netherlands)

    Sundaramoorthy, P.P.; Gill, E.; Verhoeven, C.J.M.

    2010-01-01

    Embracing reduced requirements and leveraging commercial technology has led to a fast growing small satellite industry. Although most interest in small satellites has hovered around the micro satellites through to the picosatellites, academic interest now extends up to the sub 100 g range of

  5. Satellite Remote Sensing in Seismology. A Review

    Directory of Open Access Journals (Sweden)

    Andrew A. Tronin

    2009-12-01

    Full Text Available A wide range of satellite methods is applied now in seismology. The first applications of satellite data for earthquake exploration were initiated in the ‘70s, when active faults were mapped on satellite images. It was a pure and simple extrapolation of airphoto geological interpretation methods into space. The modern embodiment of this method is alignment analysis. Time series of alignments on the Earth's surface are investigated before and after the earthquake. A further application of satellite data in seismology is related with geophysical methods. Electromagnetic methods have about the same long history of application for seismology. Stable statistical estimations of ionosphere-lithosphere relation were obtained based on satellite ionozonds. The most successful current project "DEMETER" shows impressive results. Satellite thermal infra-red data were applied for earthquake research in the next step. Numerous results have confirmed previous observations of thermal anomalies on the Earth's surface prior to earthquakes. A modern trend is the application of the outgoing long-wave radiation for earthquake research. In ‘80s a new technology—satellite radar interferometry—opened a new page. Spectacular pictures of co-seismic deformations were presented. Current researches are moving in the direction of pre-earthquake deformation detection. GPS technology is also widely used in seismology both for ionosphere sounding and for ground movement detection. Satellite gravimetry has demonstrated its first very impressive results on the example of the catastrophic Indonesian earthquake in 2004. Relatively new applications of remote sensing for seismology as atmospheric sounding, gas observations, and cloud analysis are considered as possible candidates for applications.

  6. Development of environmental monitoring satellite systems in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    With the increase in global environmental problems,the necessity and urgency of remote sensing technology being applied to environmental monitoring has been widely recognized around the world.China has launched the environment and disaster monitoring and forecasting small satellite constellation HJ-1A/B and the FY3 atmosphere and environmental satellite,but they still cannot fully satisfy requirements for environmental monitoring.This paper summarizes the current status of satellite environmental monitoring in China and the existing problems of inadequate load design and low data utilization efficiency,and discusses the demand for environmental monitoring satellites.Based on the development of foreign satellite systems for environmental monitoring,the future development and key tasks of the environmental monitoring satellite system in China is discussed,as are some related initiatives.

  7. Satellite communications for the next generation telecommunication services and networks

    Science.gov (United States)

    Chitre, D. M.

    1991-01-01

    Satellite communications can play an important role in provisioning the next-generation telecommunication services and networks, provided the protocols specifying these services and networks are satellite-compatible and the satellite subnetworks, consisting of earth stations interconnected by the processor and the switch on board the satellite, interwork effectively with the terrestrial networks. The specific parameters and procedures of frame relay and broadband integrated services digital network (B-ISDN) protocols which are impacted by a satellite delay. Congestion and resource management functions for frame relay and B-ISDN are discussed in detail, describing the division of these functions between earth stations and on board the satellite. Specific onboard and ground functions are identified as potential candidates for their implementation via neural network technology.

  8. Offshore winds mapped from satellite remote sensing

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay

    2014-01-01

    the uncertainty on the model results on the offshore wind resource, it is necessary to compare model results with observations. Observations from ground-based wind lidar and satellite remote sensing are the two main technologies that can provide new types of offshore wind data at relatively low cost....... The advantages of microwave satellite remote sensing are 1) horizontal spatial coverage, 2) long data archives and 3) high spatial detail both in the coastal zone and of far-field wind farm wake. Passive microwave ocean wind speed data are available since 1987 with up to 6 observations per day with near...

  9. Low-noise amplifiers for satellite communications

    Science.gov (United States)

    Whelehan, J.

    1984-02-01

    It is pointed out that over the past several years significant advances have been made in the overall capability of both microwave and mm-wave receivers. This is particularly apparent in the telecom market. Integral parts of advanced receiver technology are low-noise receivers. The advances currently being achieved in low-noise technology are partly based on developments in GaAs semiconductor technology. The development of high-cutoff-frequency beam lead mixer diodes has led to the development of mm-wave low-noise mixers with excellent low-noise capability. The advanced techniques are now being employed in field-deployable systems. Low noise is an important factor in satellite communications applications. Attention is given to C-band fixed satellite service, C-band parametric amplifiers, C-band FET, and X band, the Ku band, and the 30/20 GHz band.

  10. Beginnings of Satellite Navigation

    Directory of Open Access Journals (Sweden)

    Miljenko Solarić

    2008-05-01

    Full Text Available The first satellite navigation system called the Navy Navigation Satellite System (NNSS or TRANSIT was planned in the USA in 1958. It consisted of 5-6 artificial Earth satellites, was set in motion for the USA military in 1964, and in 1967 for civilian purposes. The frequency shift of received radio waves emitted from the satellite and caused by the Doppler effect was measured. The TRANSIT satellite speed of approaching or moving away was derived from that; the TRANSIT satellites emmited also their own coordinates. Then the ship's position was determined by an intersection of three hyperboloids, which were determined from differences of distances in three time intervals. Maintenance of this navigation system was stopped in 1996, but it is still being used in the USA Navy for exploring the ionosphere. Furthermore, results of Doppler measurements in international projects at the Hvar Observatory from 1982 and 1983. This was the first time in Croatia and the former country that the coordinates of the Hvar Observatory were determined in the unique world coordinate system WGS'72. The paper ends with a brief representation of the Tsiklon Doppler navigation system produced in the former Soviet Union, and there is a list of some of numerous produced and designed satellite navigation systems.Ključne riječi

  11. Designing the next phase domestic satellites - A step to communication satellites as intelligent network nodes

    Science.gov (United States)

    Majus, J.

    1982-09-01

    Applications of satellite systems for telecommunication networks are discussed in terms of harmonizing the satellite capabilities with ground-based equipment, and design for the satellites are discussed. Modern network services are becoming increasingly digitized and use optic fiber switching and information transfer. Spaceborne nodes can be used for telephony, television, packet switching, leased lines, and teletex, with reserved sectors for point-to-point communications. Space systems are capable of 100% coverage, while terrestrial systems frequently have utilization rates near 5%, implying that demand-oriented satellite expansion of local systems is the suitable methodology. Technological requirements are explored, including exclusive use of digital processing, flexible flow rates, signal transmission times, and short time availability.

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

    Science.gov (United States)

    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

  13. W频段卫星通信中正交频分复用技术的误码性能分析%Bit error rate analysis of orthogonal frequency division multiplexing technology in W-band satellite communication

    Institute of Scientific and Technical Information of China (English)

    赵乐; 宋爱民; 刘剑; 薛斌; 郭兴阳

    2015-01-01

    针对传统的卫星通信频段( C频段、Ku频段、Ka频段)应用逐渐趋于饱和的问题,研究了更高的W频段卫星通信。该频段带宽更宽,可以支持更高的数据传输速率,同等条件下天线尺寸更小并可获得更大的天线增益。正交频分复用技术具有很高的频带利用率,适合于高速数据传输,在W频段具有很好的应用前景。参照“IKNOW”项目中的链路预算,采用固态功放的Rapp模型,对OFDM技术应用在W频段卫星通信中的误码性能进行了仿真分析。仿真结果表明:在考虑功放非线性时,存在一个最佳的输入功率补偿点,使OFDM系统的误码率最低,并且发射功率越高,最佳补偿点对应的误码率越低。%Since traditional band applications ( C-band, Ku-band, Ka-band) for satellite communication will gradually tend to be saturated, the higher W-band was studied. W-band has a wider bandwidth, supports a higher data rate, acquires a smaller equipment size and a bigger antenna gain under the same conditions. Orthogonal Frequency Division Multiplexing ( OFDM) technology has a high spectrum efficiency, which makes it be suitable for high data rate transmission, so it has a good application prospect in W-band. Referring to the link budget of “IKNOW” project and using the Rapp model of solid-state power amplifier, the Bit Error Rate ( BER) of OFDM in W-band was simulated and analyzed. The simulation results show that there is a best input power backoff point which makes the BER be lowest when the nonlinear power amplifier is taken in account, and the higher the transmission power is, the lower the BER of the best input power backoff point will be.

  14. GPS卫星导航系统多频姿态测量技术研究%Research on GPS Satellite Navigation System Multi-frequency Attitude Determinat ion Technology

    Institute of Scientific and Technical Information of China (English)

    李献球; 甘兴利; 李隽

    2012-01-01

    GPS modernization provides a foundation for developing multi-frequency a ttitude determination receiver.To satisfy the attitude determination requiremen ts of platforms such as low orbit satellites,missiles,aircrafts and naval vess els,a general design scheme for multi-frequency attitude determination receive r is given,which is composed of antenna unit,measurement unit and attitude comp utation unit.Then,some key technologies are investigated,including real-time cycle slip detection and correction based on GPS multi-frequency combination no i se residual,and the ambiguity resolution algorithm for single epoch using geome try restriction.The computation equations and flows are described in detail.Fi nally,a static test is carried out for the GPS-based single frequency receiver and multi-frequency receiver for attitude determination.The test results indic a te that,as for the attitude determination accuracy and computation success rati o,the multi-frequency receiver shows better performance than that of the singl e-frequency receiver.%GPS全球卫星导航系统现代化工作,为多频姿态测量接收机的研制提供了基础条件。针对低轨卫星、导弹、飞机和舰艇等平台对姿态测量的使用需求,给出了由天线单元、测量单元和姿态解算单元构成的多频姿态测量接收机总体方案。研究了基于GPS多频组合噪声残差法实时探测与修复周跳、基于几何约束的单历元模糊度解算等关键技术,并给出了详细的计算方程和流程。对GPS单频定姿接收机和多频定姿接收机进行静态试验,证明后者在测姿精度和解算成功率方面都优于前者。

  15. Satellite-Based EMI Detection, Identification, and Mitigation

    Science.gov (United States)

    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.

  16. Technology Progress Report for Spaceborne Microwave Remote Sensing

    Institute of Scientific and Technical Information of China (English)

    JHANG Jingshan; LIU Heguang; DONG Xiaolong

    2006-01-01

    In this presentation, technological progress for China's microwave remote sensing is introduced. New developments of the microwave remote sensing instruments formeteorological satellite FY-3, ocean dynamic measurement satellite (HY-2), environment small SAR satellite (H J-1C) and China's lunar exploration satellite (Chang'E-1), are reported.

  17. Domestic Communication Satellites

    Science.gov (United States)

    Horowitz, Andrew

    1974-01-01

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

  18. Biological satellite Kosmos-936

    Science.gov (United States)

    Vedeshin, L. A.

    1978-01-01

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

  19. Small Satellite Transporter Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary objective is to determine whether this small satellite transporter is capable of transporting at least four 6U CubeSats is possible for a given set of...

  20. 5th China Satellite Navigation Conference

    CERN Document Server

    Jiao, Wenhai; Wu, Haitao; Lu, Mingquan

    2014-01-01

    China Satellite Navigation Conference (CSNC) 2014 Proceedings presents selected research papers from CSNC2014, held on 21-23 May in Nanjing, China. The theme of CSNC2014 is 'BDS Application: Innovation, Integration and Sharing'. These papers discuss the technologies and applications of the Global Navigation Satellite System (GNSS), and the latest progress made in the China BeiDou System (BDS) especially. They are divided into 9 topics to match the corresponding sessions in CSNC2014, which broadly covered key topics in GNSS. Readers can learn about the BDS and keep abreast of the latest advances in GNSS techniques and applications.  SUN Jiadong is the Chief Designer of the Compass/ BDS, and the Academician of Chinese Academy of Sciences (CAS); JIAO Wenhai is a researcher at China Satellite Navigation Office; WU Haitao is a professor at Navigation Headquarters, CAS; LU Mingquan is a professor at Department of Electronic Engineering of Tsinghua University.

  1. The Archimedes satellite system

    Science.gov (United States)

    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.

  2. ASTRID II satellit projekt

    DEFF Research Database (Denmark)

    Jørgensen, John Leif; Primdahl, Fritz

    1997-01-01

    The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan.......The report describes the instruments developed for the Swedish micro satellite "ASTRID II". Specifications of the two instruments realized under this contract, a Stellar Compass and a CSC magnetometer are given follwed by a description of the project status and plan....

  3. Satellite formation. II

    Science.gov (United States)

    Harris, A. W.

    1978-01-01

    A satellite formation model is extended to include evolution of planetary ring material and elliptic orbital motion. In this model the formation of the moon begins at a later time in the growth of the earth, and a significant fraction of the lunar material is processed through a circumterrestrial debris cloud where volatiles might have been lost. Thus, the chemical differences between the earth and moon are more plausibly accounted for. Satellites of the outer planets probably formed in large numbers throughout the growth of those planets. Because of rapid inward evolution of the orbits of small satellites, the present satellite systems represent only satellites formed in the last few percent of the growths of their primaries. The rings of Saturn and Uranus are most plausibly explained as the debris of satellites disrupted within the Roche limit. Because such a ring would collapse onto the planet in the course of any significant further accretion by the planet, the rings must have formed very near or even after the conclusion of accretion.

  4. Television broadcast from space systems: Technology, costs

    Science.gov (United States)

    Cuccia, C. L.

    1981-01-01

    Broadcast satellite systems are described. The technologies which are unique to both high power broadcast satellites and small TV receive-only earth terminals are also described. A cost assessment of both space and earth segments is included and appendices present both a computer model for satellite cost and the pertinent reported experience with the Japanese BSE.

  5. Technology Progress Report for Microwave Remote Sensing

    Institute of Scientific and Technical Information of China (English)

    JIANG Jingshan; DONG Xiaolong; LIU Heguang

    2004-01-01

    In this presentation, technological progress for China's microwave remote sensing is introduced. New developments of the microwave remote sensing instruments for China's lunar exploration satellite (Chang'E-1), meteorological satellite FY-3 and ocean dynamic measurement satellite (HY-2) are reported.

  6. Determination of the key parameters affecting historic communications satellite trends

    Science.gov (United States)

    Namkoong, D.

    1984-01-01

    Data representing 13 series of commercial communications satellites procured between 1968 and 1982 were analyzed to determine the factors that have contributed to the general reduction over time of the per circuit cost of communications satellites. The model by which the data were analyzed was derived from a general telecommunications application and modified to be more directly applicable for communications satellites. In this model satellite mass, bandwidth-years, and technological change were the variable parameters. A linear, least squares, multiple regression routine was used to obtain the measure of significance of the model. Correlation was measured by coefficient of determination (R super 2) and t-statistic. The results showed that no correlation could be established with satellite mass. Bandwidth-year however, did show a significant correlation. Technological change in the bandwidth-year case was a significant factor in the model. This analysis and the conclusions derived are based on mature technologies, i.e., satellite designs that are evolutions of earlier designs rather than the first of a new generation. The findings, therefore, are appropriate to future satellites only if they are a continuation of design evolution.

  7. A Space Based Solar Power Satellite System

    Science.gov (United States)

    Engel, J. M.; Polling, D.; Ustamujic, F.; Yaldiz, R.; et al.

    2002-01-01

    (SPoTS) supplying other satellites with energy. SPoTS is due to be commercially viable and operative in 2020. of Technology designed the SPoTS during a full-time design period of six weeks as a third year final project. The team, organized according to the principles of systems engineering, first conducted a literature study on space wireless energy transfer to select the most suitable candidates for use on the SPoTS. After that, several different system concepts have been generated and evaluated, the most promising concept being worked out in greater detail. km altitude. Each SPoTS satellite has a 50m diameter inflatable solar collector that focuses all received sunlight. Then, the received sunlight is further redirected by means of four pointing mirrors toward four individual customer satellites. A market-analysis study showed, that providing power to geo-stationary communication satellites during their eclipse would be most beneficial. At arrival at geo-stationary orbit, the focused beam has expended to such an extent that its density equals one solar flux. This means that customer satellites can continue to use their regular solar arrays during their eclipse for power generation, resulting in a satellite battery mass reduction. the customer satellites in geo-stationary orbit, the transmitted energy beams needs to be pointed with very high accuracy. Computations showed that for this degree of accuracy, sensors are needed, which are not mainstream nowadays. Therefore further research must be conducted in this area in order to make these high-accuracy-pointing systems commercially attractive for use on the SPoTS satellites around 2020. Total 20-year system lifetime cost for 18 SPoT satellites are estimated at approximately USD 6 billion [FY2001]. In order to compete with traditional battery-based satellite power systems or possible ground based wireless power transfer systems the price per kWh for the customer must be significantly lower than the present one

  8. Satellite Formation based on SDDF Method

    Directory of Open Access Journals (Sweden)

    Yu Wang

    2014-04-01

    Full Text Available The technology of satellite formation flying has being a research focus in flight application. The relative position and velocity between satellites are basic parameters to achieve the control of formation flight during the satellite formation flying mission. In order to improve the navigation accuracy, a new filter different from Extended Kalman Filter (EKF should be adopted to estimate the errors of relative position and velocity, which is based on the nonlinearity of the kinetic model for the satellite formation flying. A nonlinear Divided Difference Filter (DDF based on Stirling interpolation formula was proposed in this paper. According to the linearity of the measurement equation for the filter, a simplified differential filter was designed by means of expanding the polynomial of the nonlinear system equation and linear approximating of the finite differential interpolation. Digital simulation experiment for the relative positioning of satellite formation flying was carried out. The result demonstrates that the filter proposed in this paper has a higher filtering accuracy, faster convergence speed and better stability. Compared with the EKF, the estimation accuracy of the relative position and velocity has improved by 77.1%and 47% respectively in the method of simplified DDF, which indicates the significance for practical applications. 

  9. Potential markets for advanced satellite communications

    Science.gov (United States)

    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.

  10. Potential markets for advanced satellite communications

    Science.gov (United States)

    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.

  11. Satellite Communications for ATM

    Science.gov (United States)

    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

  12. Atoms of helium in interstellar and interplanetary medium. 1. Observations of scattering ultraviolet radiation in lines of HI lambda 1216 A and HeI lambda 584 A by the ''Prognoz-5'' and ''Prognoz-6'' satellites

    Energy Technology Data Exchange (ETDEWEB)

    Burgin, M.S.; Kurt, V.G.; Mironova, E.N.; Prokhorenko, V.I.; Ehjsmont, N.A.; Berto, Zh.L.; Dalod' e, F.

    A review of observation results of the joint Soviet- French experiment on the measurement of scattering ultraviolet radiation in interplanetary medium in HIlambda1216 A and HeI 584 A hydrogen lines, is presented. The four-channel photometer Oas installed at two high-apogee satellites of ''Prognoz-5'' and ''Prognoz-6''. The sky scanning was performed due to satellite rotation around its axis directed to the Sun. A vessel with hydrogen was set up in the HILsub(..cap alpha..) channel in order to measure the Lsub(..cap alpha..) line width. All parameters connected with the Sun motion in interplanetary medium were determined.

  13. China's Meteorological Satellite Application System

    Institute of Scientific and Technical Information of China (English)

    Zhang Jiashen

    2008-01-01

    @@ China's meteorological satellite program consists of five systems,namely the satellite system,the launch vehicle system,the launch center system,TT&C and the ground application system.The satellite system consists of FengYun (FY) polar orbiting series and FY geostationary series,which are launched by LM launch vehicles from Taiyan Satellite Launch Center (TSLC) and Xichang Satellite Launch Center (XSLC) respectively.

  14. LTE Adaptation for Mobile Broadband Satellite Networks

    Directory of Open Access Journals (Sweden)

    Bastia Francesco

    2009-01-01

    Full Text Available One of the key factors for the successful deployment of mobile satellite systems in 4G networks is the maximization of the technology commonalities with the terrestrial systems. An effective way of achieving this objective consists in considering the terrestrial radio interface as the baseline for the satellite radio interface. Since the 3GPP Long Term Evolution (LTE standard will be one of the main players in the 4G scenario, along with other emerging technologies, such as mobile WiMAX; this paper analyzes the possible applicability of the 3GPP LTE interface to satellite transmission, presenting several enabling techniques for this adaptation. In particular, we propose the introduction of an inter-TTI interleaving technique that exploits the existing H-ARQ facilities provided by the LTE physical layer, the use of PAPR reduction techniques to increase the resilience of the OFDM waveform to non linear distortion, and the design of the sequences for Random Access, taking into account the requirements deriving from the large round trip times. The outcomes of this analysis show that, with the required proposed enablers, it is possible to reuse the existing terrestrial air interface to transmit over the satellite link.

  15. A guide to the literature on application of communications satellites to educational development

    Science.gov (United States)

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

    1972-01-01

    A review of literature dealing with communication satellite technology is presented for the nontechnical reader with emphasis on the educational aspects. An introduction is provided for: satellite technology; nontechnological aspects including economic, organizational, social, and political factors; and educational and developmental uses. A guide to selected literature, and a bibliography are included.

  16. COMMUNICATION SATELLITES FOR EDUCATION, SCIENCE AND CULTURE. REPORTS AND PAPERS ON MASS COMMUNICATION, NO. 53.

    Science.gov (United States)

    SCHRAMM, WILBUR

    THE TECHNOLOGY OF COMMUNICATION SATELLITES IS SUFFICIENTLY ADVANCED THAT CONCERNED AGENCIES, SUCH AS UNESCO, SHOULD BEGIN TO PLAN FOR THEIR USE IN EXCHANGE OF DATA, NEWS TRANSMISSION, CULTURAL EXCHANGE, AND EDUCATION. GROUNDWORK IN TECHNOLOGY, IN THE DESIGN OF A SATELLITE COMMUNICATION SYSTEM, IN VALUE JUDGMENTS, IN AGREEMENTS OF COOPERATION AND…

  17. 基于WorldWind平台的卫星云图模拟技术研究%Study of Satellite Cloud Image Simulation Technology Based on WorldWind

    Institute of Scientific and Technical Information of China (English)

    孙恺; 徐晓刚

    2011-01-01

    卫星云图是目前最重要的气象信息来源之一.实现卫星云图的模拟对于灾害预防、评估等工作具有十分重要的意义.首先分析了WorldWind开源平台的系统框架.针对于彩色卫星云图,改进了一种基于图像色彩和灰度值的算法,能够较好地分割提取出云层区域.进而在开源平台WorldWind上采用多层纹理映射的方式实现了卫星云图的模拟.%Satellite cloud image is one of the most important sources of the weather information, and it is of much significance for disaster forecasting and evaluating to do the research of satellite cloud image simulation. The framework of the open-source platform WorldWind was discussed. For the satellite images, the cloud regions were analyzed and segmented by an improved algorithm based on the color value and gray scale. The multilayer texture mapping algorithm is utilized on satellite cloud image simulation, and the procession is integrated to the open-source platform WorldWind.

  18. Cyber security with radio frequency interferences mitigation study for satellite systems

    Science.gov (United States)

    Wang, Gang; Wei, Sixiao; Chen, Genshe; Tian, Xin; Shen, Dan; Pham, Khanh; Nguyen, Tien M.; Blasch, Erik

    2016-05-01

    Satellite systems including the Global Navigation Satellite System (GNSS) and the satellite communications (SATCOM) system provide great convenience and utility to human life including emergency response, wide area efficient communications, and effective transportation. Elements of satellite systems incorporate technologies such as navigation with the global positioning system (GPS), satellite digital video broadcasting, and information transmission with a very small aperture terminal (VSAT), etc. The satellite systems importance is growing in prominence with end users' requirement for globally high data rate transmissions; the cost reduction of launching satellites; development of smaller sized satellites including cubesat, nanosat, picosat, and femtosat; and integrating internet services with satellite networks. However, with the promising benefits, challenges remain to fully develop secure and robust satellite systems with pervasive computing and communications. In this paper, we investigate both cyber security and radio frequency (RF) interferences mitigation for satellite systems, and demonstrate that they are not isolated. The action space for both cyber security and RF interferences are firstly summarized for satellite systems, based on which the mitigation schemes for both cyber security and RF interferences are given. A multi-layered satellite systems structure is provided with cross-layer design considering multi-path routing and channel coding, to provide great security and diversity gains for secure and robust satellite systems.

  19. Videoconferences via Satellite: Opening Congress to the People?

    Science.gov (United States)

    Carter, Luther J.

    1977-01-01

    Describes the legislative hearing conducted June 8, 1977, by the Senate Subcommittee on Science, Technology, and Space which was a videoconference via satellite to interview witnesses located 800 miles away in Illinois. Future possible use of the technology involved is reviewed. (SL)

  20. Update on the Solar Power Satellite transmitter design

    Energy Technology Data Exchange (ETDEWEB)

    Brown, W.C.

    1986-01-01

    A number of remaining problems in the conceptual design of the transmitting antenna for the Solar Power Satellite have been solved as a result of additional technology development. Much of the technology was derived from the conceptual design of a ground-based transmitting antenna for beaming power to a high altitude airship or airplane.

  1. Optical transceivers for interconnections in satellite payloads

    Science.gov (United States)

    Karppinen, Mikko; Heikkinen, Veli; Juntunen, Eveliina; Kautio, Kari; Ollila, Jyrki; Sitomaniemi, Aila; Tanskanen, Antti

    2013-02-01

    The increasing data rates and processing on board satellites call for the use of photonic interconnects providing high-bitrate performance as well as valuable savings in mass and volume. Therefore, optical transmitter and receiver technology is developed for aerospace applications. The metal-ceramic-packaging with hermetic fiber pigtails enables robustness for the harsh spacecraft environment, while the 850-nm VCSEL-based transceiver technology meets the high bit-rate and low power requirements. The developed components include 6 Gbps SpaceFibre duplex transceivers for intra-satellite data links and 40 Gbps parallel optical transceivers for board-to-board interconnects. Also, integration concept of interchip optical interconnects for onboard processor ICs is presented.

  2. HISTORICAL RESTORSPECTIVE OF COMUNICATION SATELLITES

    Directory of Open Access Journals (Sweden)

    Francisco Sacristán Romero

    2006-04-01

    Full Text Available SUMMARY This article comprises of an investigation that approaches a so complex subject and in process as the trajectory, from its birth like project, of the Spanish satellite of communications HISPASAT. HISPASAT supposes to enter in the more fascinating world of the technologies out poste with the risk of believing have approval part of the possibilities that it offers, when in fact not we have begun the study of a plan in transition. The investigators that come behind us will extend and enrich the information on the great legacy which, from already, are leaving net Spanish technical and human resources. HISPASAT offers the possibility that the languages and the cultures of our country transfer the international borders and they enter in corners of Europe, America and Africa where it had a superficial knowledge of our customs, wealthy and stronger traditions.

  3. Effect of Ionosphere on Geostationary Communication Satellite Signals

    Science.gov (United States)

    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

  4. Satellite Constellation Optimization for Turkish Armed Forces

    Science.gov (United States)

    2013-03-01

    attack Turkish military and civilians (especially but not only) in the mountainous eastern part of the country, where they take advantage of this...terrorist attack at the moment should have a higher priority than a law enforcement body monitoring illegal trafficking at the same time, and this...consider the antenna size of an IRIDIUM satellite phone, communications with such an antenna are achievable with today’s technology. The calculations

  5. Global trends in satellite-based emergency mapping.

    Science.gov (United States)

    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.

  6. Global trends in satellite-based emergency mapping

    Science.gov (United States)

    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.

  7. Global trends in satellite-based emergency mapping

    Science.gov (United States)

    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

    2016-07-01

    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.

  8. Radio occultation based on BeiDou satellite navigation

    Science.gov (United States)

    Jiang, Hu; Hu, Haiying; Shen, Xue-min; Gong, Wenbin; Zhang, Yonghe

    2014-11-01

    With the development of GNSS systems, it has become a tendency that radio occultation is used to sense the Earth's atmosphere. By this means, the moisture, temperature, pressure, and total electron content can be derived. Based on the sensing results, more complicated models for atmosphere might come into being. Meteorology well benefits from this technology. As scheduled, the BD satellite navigation system will have a worldwide coverage by the end of 2020. Radio occultation studies in China have been highlighted in the recent decade. More and more feasibilities reports have been published in either domestic or international journals. Herein, some scenarios are proposed to assess the coverage of radio occultation based on two different phases of BD satellite navigation system. Phase one for BD is composed of GEO,IGSO and several MEO satellites. Phase two for BD consists mostly of 24 MEO satellites, some GEO and IGSO satellites. The characteristics of radio occultation based on these two phases are presented respectively.

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

    Science.gov (United States)

    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

  10. The German joint research project "concepts for future gravity satellite missions"

    Science.gov (United States)

    Reubelt, Tilo; Sneeuw, Nico; Fichter, Walter; Müller, Jürgen

    2010-05-01

    Within the German joint research project "concepts for future gravity satellite missions", funded by the Geotechnologies programme of the German Federal Ministry of Education and Research, options and concepts for future satellite missions for precise (time-variable) gravity field recovery are investigated. The project team is composed of members from science and industry, bringing together experts in geodesy, satellite systems, metrology, sensor technology and control systems. The majority of team members already contributed to former gravity missions. The composition of the team guarantees that not only geodetic aspects and objectives are investigated, but also technological and financial constraints are considered. Conversely, satellite, sensor and system concepts are developed and improved in a direct exchange with geodetic and scientific claims. The project aims to develop concepts for both near and mid-term future satellite missions, taking into account e.g. advanced satellite formations and constellations, improved orbit design, innovative metrology and sensor systems and advances in satellite systems.

  11. Solar Power Satellites

    CERN Document Server

    Flournoy, Don M

    2012-01-01

    Communication satellites are a $144 billion industry. Is there any space-based industry that could possibly beat that market? 'Solar Power Satellites' shows why and how the space satellite industry will soon begin expanding its market from relaying signals to Earth to generating energy in space and delivering it to the ground as electricity. In all industrialized nations, energy demand is growing exponentially. In the developing world, the need for energy is as basic as food and water. The Sun's energy is available everywhere, and it is non-polluting. As business plans demonstrate its technical feasibility, commercial potential, and environmental acceptability, every country on Earth will look to space for the power it needs.

  12. AVS on satellite

    Science.gov (United States)

    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.

  13. Satellite Control Laboratory

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Bak, Thomas

    2001-01-01

    The Satellite Laboratory at the Department of Control Engineering of Aalborg University (SatLab) is a dynamic motion facility designed for analysis and test of micro spacecraft. A unique feature of the laboratory is that it provides a completely gravity-free environment. A test spacecraft...... is suspended on an air bearing, and rotates freely in 3 degrees of freedom. In order to avoid any influence of the gravitational force the centre of mass of the satellite is placed in the geometric centre of the air bearing by an automatic balancing system. The test spacecraft is equipped with a three......-axis magnetometer, three piezoelectric gyros, and four reaction wheels in a tetrahedron configuration. The operation of the spacecraft is fully autonomous. The data flow between the transducers and the onboard computer placed physically outside the satellite is provided by a radio link. The purpose...

  14. Laser Communication Experiments with Artemis Satellite

    Science.gov (United States)

    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

  15. Satellite Contributions to Global Change Studies

    Science.gov (United States)

    Parkinson, Claire L.

    2009-01-01

    sophisticated climate models, in situ process studies, and data sets that extend back well before the introduction of satellite technology. Nonetheless, the repetitive, global view provided by satellites is contributing in a major way to our improved recognition of how the Earth im changing, a recognition that is none too soon in view of the magnitude of the impacts that humans can now have.

  16. 622 Mbps High-speed satellite communication system for WINDS

    Science.gov (United States)

    Ogawa, Yasuo; Hashimoto, Yukio; Yoshimura, Naoko; Suzuki, Ryutaro; Gedney, Richard T.; Dollard, Mike

    2006-07-01

    WINDS is the experimental communications satellite currently under joint development by Japanese Aerospace Exploration Agency (JAXA) and the National Institute of Information and Communications Technology (NICT). The high-speed satellite communication system is very effective for quick deployment of high-speed networks economically. The WINDS will realize ultra high-speed networking and demonstrate operability of satellite communication systems in high-speed internet. NICT is now developing high-speed satellite communication system for WINDS. High-speed TDMA burst modem with high performance TPC error correction is underdevelopment. Up to the DAC on the transmitter and from the ADC on the receiver, all modem functions are performed in the digital processing technology. Burst modem has been designed for a user data rate up to 1244 Mbps. NICT is developing the digital terminal as a user interface and a network controller for this earth station. High compatibility with the Internet will be provided.

  17. Small satellites for global coverage: Potential and limits

    Science.gov (United States)

    Sandau, Rainer; Brieß, Klaus; D'Errico, Marco

    2010-11-01

    There is an increasing need for Earth Observation (EO) missions to meet the information requirements in connection with Global Change Studies. Small and cost-effective missions are powerful tools to flexibly react to information requirements with space-borne solutions. Small satellite missions can be conducted relatively quickly and inexpensively by using commercial off-the-shelf-technologies, or they can be enhanced by using advanced technologies. A new class of advanced small satellites, including autonomously operating "intelligent" satellites may be created, opening new fields of application. The increasing number of small satellites and their applications drive developments in the fields of small launchers, small ground station networks, cost-effective data distribution methods, and cost-effective management and quality assurance procedures. There are many advantages of small satellite missions, like more frequent mission opportunities, a faster return of data, larger variety of missions, more rapid expansion of the technical and/or scientific knowledge base, greater involvement of small industry, feasibility by universities and others. This paper deals with general trends in the field of small satellite missions for Earth observation. Special attention is given to the potential of spatial, spectral, and temporal resolution of small satellite based systems. Examples show small satellites offer also the unique possibility to install affordable constellations to provide good daily coverage of the globe and/or allow us to observe dynamic phenomena. The facts and examples given in this paper lead to the conclusion: Small satellites are already powerful tools for monitoring global, regional and local phenomena. In the future, their application spectrum will even broaden based on the ongoing development in many areas of technology and observation techniques.

  18. Declassified intelligence satellite photographs

    Science.gov (United States)

    ,

    1998-01-01

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

  19. Oceanography from satellites

    Science.gov (United States)

    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.

  20. Satellite oceanography - The instruments

    Science.gov (United States)

    Stewart, R. H.

    1981-01-01

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