DOCSLIB.ORG

===How to Get Thousands of TV Channels on Your PC… Http

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

==== ==== How to Get Thousands of TV Channels on Your PC… http://www.satellite-direct-online.co.cc/ ==== ==== Introduction and Brief History of Satellites A satellite is any object that orbits another object (which is known as its primary). All masses that are part of the solar system, including the Earth, are satellites either of the Sun, or satellites of those objects, such as the Moon. It is not always a simple matter to decide which is the 'satellite' in a pair of bodies. Because all objects exert gravity, the motion of the primary object is also affected by the satellite. If two objects are ufficiently similar in mass, they are generally referred to as a binary system rather than a primary object and satellite. The general criterion for an object to be a satellite is that the center of mass of the two objects is inside the primary object. In popular usage, the term 'satellite' normally refers to an artificial satellite (a man-made object that orbits the Earth or another body). In May, 1946, the Preliminary Design of an Experimental World-Circling Spaceship stated, "A satellite vehicle with appropriate instrumentation can be expected to be one of the most potent scientific tools of the Twentieth Century. The achievement of a satellite craft would produce repercussions comparable to the explosion of the atomic bomb..." The space age began in 1946, as scientists began using captured German V-2 rockets to make measurements in the upper atmosphere. Before this period, scientists used balloons that went up to 30 km and radio waves to study the ionosphere. From 1946 to 1952, upper-atmosphere research was conducted using V-2s and Aerobee rockets. This allowed measurements of atmospheric pressure, density, and temperature up to 200 km. The U.S. had been considering launching orbital satellites since 1945 under the Bureau of Aeronautics of the United States Navy. The Air Force's Project RAND eventually released the above report, but did not believe that the satellite was a potential military weapon; rather they considered it to be a tool for science, politics, and propaganda. Following pressure by the American Rocket Society, the National Science Foundation, and the International Geophysical Year, military interest picked up and in early 1955 the Air Force and Navy were working on Project Orbiter, which involved using a Jupiter C rocket to launch a small satellite called Explorer 1 on January 31, 1958. On July 29, 1955, the White House announced that the U.S. intended to launch satellites by the spring of 1958. This became known as Project Vanguard. On July 31, the Soviets announced that they intended to launch a satellite by the fall of 1957 and on October 4, 1957 Sputnik I was launched into orbit, which triggered the Space Race between the two nations. The largest artificial satellite currently orbiting the earth is the International Space Station, which can sometimes be seen with the unaided human eye. Types of satellites ·Astronomical satellites: These are satellites used for observation of distant planets, galaxies, and other outer space objects. ·Communications satellites: These are artificial satellites stationed in space for the purposes of telecommunications using radio at microwave frequencies. Most communications satellites use geosynchronous orbits or near-geostationary orbits, although some recent systems use low Earth-orbiting satellites. ·Earth observation satellites are satellites specifically designed to observe Earth from orbit, similar to reconnaissance satellites but intended for non-military uses such as environmental monitoring, meteorology, map making etc. (See especially Earth Observing System.) ·Navigation satellites are satellites which use radio time signals transmitted to enable mobile receivers on the ground to determine their exact location. The relatively clear line of sight between the satellites and receivers on the ground, combined with ever-improving electronics, allows satellite navigation systems to measure location to accuracies on the order of a few metres in real time. ·Reconnaissance satellites are Earth observation satellite or communications satellite deployed for military or intelligence applications. Little is known about the full power of these satellites, as governments who operate them usually keep information pertaining to their reconnaissance satellites classified. ·Solar power satellites are proposed satellites built in high Earth orbit that use microwave power transmission to beam solar power to very large antenna on Earth where it can be used in place of conventional power sources. ·Space stations are man-made structures that are designed for human beings to live on in outer space. A space station is distinguished from other manned spacecraft by its lack of major propulsion or landing facilities -- instead, other vehicles are used as transport to and from the station. Space stations are designed for medium-term living in orbit, for periods of weeks, months, or even years. ·Weather satellites are satellites that primarily are used to monitor the weather and/or climate of the Earth. ·Miniaturized satellites are satellites of unusually low weights and small sizes. New classifications are used to categorize these satellites: minisatellite (500-200 kg), microsatellite (below 200 kg), nanosatellite (below 10 kg). Orbit types Many times satellites are characterized by their orbit. Although a satellite may orbit at almost any height, satellites are commonly categorized by their altitude: ·Low Earth Orbit (LEO: 200 - 1200km above the Earth's surface) ·Medium Earth Orbit (ICO or MEO: 1200 - 35286 km) ·Geosynchronous Orbit (GEO: 35786 km above Earth's surface) and Geostationary Orbit ( zero inclination geosynchronous orbit). These orbits are of particular interest for communication satellites and will be discussed in detail later. ·High Earth Orbit (HEO: above 35786 km) The following orbits are special orbits that are also used to categorize satellites: ·Molniya orbits: Is a class of a highly elliptic orbit. A satellite placed in this orbit spends most of its time over a designated area of the earth, a phenomenon known as apogee dwell. Molniya orbits are named after a series of Soviet/Russian Molniya communications satellites that have been using this class of orbits since the mid 1960s. ·Heliosynchronous or sun-synchronous orbit: A heliosynchronous orbit, or more commonly a sun-synchronous orbit is an orbit in which an object always passes over any given point of the Earth's surface at the same local solar time. This is a useful characteristic for satellites that image the earth's surface in visible or infrared wavelengths (e.g. weather, spy and remote sensing satellites). ·Polar orbit : A satellite in a polar orbit passes above or nearly above both poles of the planet (or other celestial body) on each revolution. ·Hohmann transfer orbit: For this particular orbit type, it is more common to identify the satellite as a spacecraft. In astronautics and aerospace engineering, the Hohmann transfer orbit is an orbital maneuver that moves a spacecraft from one orbit to another. ·Supersynchronous orbit or drift orbit : orbit above GEO. Satellites will drift in a westerly direction. ·Subsynchronous orbit or drift orbit: orbits close to but below GEO. Used for satellites undergoing station changes in an eastern direction. Communication Satellites A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications. Modern communications satellites use geosynchronous orbits, Molniya orbits or low Earth orbits. For fixed services, communications satellites provide a technology complementary to that of fiber optic submarine communication cables. For mobile applications, such as communications to ships and planes satellite based communicationis only the viable means of communications as application of other technologies, such as cable, are impractical or impossible. Early missions: The origin of satellite communication can be traced to an article written by Arthur C. Clarke in 1945. He suggested that a radio relay satellite in an equatorial orbit with a period of 24 hours would remain stationary with respect to earth's surface and can be used for long-range radio communication, as it will over come the limitations imposed by earth curvature. Sputnik 1, The world's first artificial (non communication) satellite, was launched on October 4, 1957. The first satellite to relay communications was Project SCORE in 1958, which used a tape recorder to store and forward voice messages. It was used to send a Christmas greeting to the world from President Eisenhower. NASA launched an Echo satellite in 1960. This 100-foot aluminized Mylar balloon served as a passive reflector for radio communications. Courier 1B, (built by Philco) also was launched in 1960, was the world's first active repeater satellite. Given below are the details of milestones in satellite communcation history: - ·Herman Potocnik - describes a space station in geosynchronous orbit - 1928 ·Arthur C. Clarke - proposes a station in geosynchronous orbit to relay communications and broadcast television - 1945 ·Project SCORE - first communications satellite - 1958 ·Echo I - first passive reflector satellite - August 1960 ·Courier 1B - first active repeater satellite - October 1960 ·Telstar - the
Recommended publications
  • 6 Orbit Relative to the Sun. Crossing Times

    6 Orbit Relative to the Sun. Crossing Times

    6 Orbit Relative to the Sun. Crossing Times We begin by studying the position of the orbit and ground track of an arbi- trary satellite relative to the direction of the Sun. We then turn more specif- ically to Sun-synchronous satellites for which this relative position provides the very definition of their orbit. 6.1 Cycle with Respect to the Sun 6.1.1 Crossing Time At a given time, it is useful to know the local time on the ground track, i.e., the LMT, deduced in a straightforward manner from the UT once the longitude of the place is given, using (4.49). The local mean time (LMT) on the ground track at this given time is called the crossing time or local crossing time. To obtain the local apparent time (LAT), one must know the day of the year to specify the equation of time ET. In all matters involving the position of the Sun (elevation and azimuth) relative to a local frame, this is the time that should be used. The ground track of the satellite can be represented by giving the crossing time. We have chosen to represent the LMT using colour on Colour Plates IIb, IIIb and VII to XI. For Sun-synchronous satellites such as MetOp-1, it is clear that the cross- ing time (in the ascending or descending direction) depends only on the latitude. At a given place (except near the poles), one crossing occurs during the day, the other at night. For the HEO of the Ellipso Borealis satellite, the stability of the crossing time also shows up clearly.
  • United States Patent (19) 11 Patent Number: 5,716,029 Spitzer Et Al

    United States Patent (19) 11 Patent Number: 5,716,029 Spitzer Et Al

    I US005716029A United States Patent (19) 11 Patent Number: 5,716,029 Spitzer et al. 45 Date of Patent: Feb. 10, 1998 54 CONSTANTSUN ANGLE TRANSFER ORBIT Meserole, J., "Launch Costs to GEO Using Solar Powered SEQUENCE AND METHOD USING Orbit Transfer Vehicles". American Institute of Aeronautics ELECTRIC PROPULSION and Astronautic (AIAA) Paper 93-2219. AIAAJSAE (75) Inventors: Arnon Spitzer, Los Angeles, Calif.; ASME/ASEE 29th Joint Propulsion Conference and Solomon A. De Picciotto, Aurora, Colo. Exhibit. Jun. 28-30, 1993. 73 Assignee: Hughes Electronics, Los Angeles, Free, B. "High Altitude Orbit Raising With On-Board Calif. Electric Power", International Electric Propulsion Confer ence Paper 93-205, American Institute Of Aeronautics and (21) Appl. No.: 558,572 Astronautics AIAA/AIDAVDGLA/JSASS 23rd International 22 Filed: Oct. 31, 1995 Electric Propulsion Conference. Sep. 13–16, 1993. Related U.S. Application Data Primary Examiner-Galen L. Barefoot 63 Continuation-in-part of Ser. No. 217,791, Mar. 25, 1994, Attorney, Agent, or Firm-Elizabeth E. Leitereg; Terje Pat No. 5,595,360. Gudmestad; Wanda K. Denson-Low (51) Int. Cl. ... ... B64G 1/10 52 U.S.C. ................................................... 244/158 R 57 ABSTRACT 58) Field of Search ................................ 244/158 R, 164, 244/168, 169, 172 An apparatus and method for translating a spacecraft (102. 108) from an injection orbit (114) about a central body (100) 56) References Cited to synchronous orbit (122) in a time efficient manner. The U.S. PATENT DOCUMENTS spacecraft (102, 108) includes propulsion thrusters (50) 4,943,014 7/1990 Harwood et al. ....................... 244/169 which are fired in predetermined timing sequences con trolled by a controller (64) in relation to the apogee (118) FOREIGN PATENT DOCUMENTS and perigee (120) of the injection orbit (114) and successive 0 047 211 3/1982 European Pat.
  • The Aerospace Update

    The Aerospace Update

    The Aerospace Update First Light from a Gravitational-Wave Event Oct. 17, 2017 Video Credit: NASA's Goddard Space Flight Center/CI Lab First Light from a Gravitational-Wave Event For the first time ever, scientists have spotted both gravitational waves and light coming from the same cosmic event — in this case, the cataclysmic merger of two super dense stellar corpses known as neutron stars. The landmark discovery initiates the field of "multi-messenger astrophysics," which promises to reveal exciting new insights about the cosmos, researchers said. The find also provides the first solid evidence that neutron-star smashups are the source of much of the universe's gold, platinum and other heavy elements. Source: Mike Wall, Space.com Image Credit: Robin Dienel, Carnegie Institution for Science ATLAS 5 Launches Classified NROL 52 Satellite A covert communications relay station to route spy satellite data directly to users was successfully launched by a million-pound Atlas 5 rocket overnight. The United Launch Alliance rocket left Cape Canaveral under the cover of darkness on Sunday, Oct. 15th, dodging rain showers while speeding through decks of clouds, for a trek to geosynchronous transfer orbit to deploy the NROL-52 spacecraft. The fifth launch attempt proved to be the charm for NROL-52 after four thwarted tries over the past week, mainly due to bad weather. Video courtesy of United Launch Alliance Source: Justin Ray @ SpaceFlightNow.com SpaceX Launches Third Pre-Flown Rocket with EchoStar-SES Satellite, Lands Booster Maintaining a brisk flight rate three days after its last launch, SpaceX sent a Falcon 9 booster powered by a reused first stage into orbit on Wednesday evening, Oct 11th from Florida with an Airbus-built communications satellite for SES and EchoStar.
  • III III || US005595360A United States Patent (19) 11 Patent Number: 5,595,360 Spitzer 45) Date of Patent: Jan

    III III || US005595360A United States Patent (19) 11 Patent Number: 5,595,360 Spitzer 45) Date of Patent: Jan

    III III || US005595360A United States Patent (19) 11 Patent Number: 5,595,360 Spitzer 45) Date of Patent: Jan. 21, 1997 54) OPTIMAL TRANSFER ORBIT TRAJECTORY Meserole, J., "Launch Costs To GEO Using Solar Powered USENGELECTRIC PROPULSION Orbit Transfer Vehicles', American Institute of Aeronautics and Astronautic (AIAA) Paper 93-2219, AIAA/SAE/ 75) Inventor: Arnon Spitzer, Los Angeles, Calif. ASME/ASEE 29th Joint Propulsion Conference and Exhibit, Jun. 28-30, 1993. (73) Assignee: Hughes Aircraft Company, Los Free, B. "High Altitude Orbit Raising With On-Board Angeles, Calif. Electric Power”, International Electric Propulsion Confer ence Paper 93-205, American Institute Of Aeronautics and (21) Appl. No.: 217,791 Astronautics AIAA/AIDA/DGLA/JSASS 23rd International (22 Filed: Mar 25, 1994 Electric Propulsion Conference, Sep. 13-16, 1993. Parkhash, "Electric Propulsion for Space Missions' Electri (51) int. Cl. ................ B64G 1/10 cal India vol. 19, No. 7, pp. 5-18., Apr. 1979. (52 U.S. C. ........................................................ 244/158 R Davison, "orbit Expansion by Microthrust” Royal Aircraft 58 Field of Search ................................ 244/158 R, 164, Est. Tech Report 67249 Sep. 1967. 244/172, 168, 169 Primary Examiner-Galen L. Barefoot 56 References Cited Attorney, Agent, or Firm-Elizabeth E. Leitereg; Terje Gud U.S. PATENT DOCUMENTS mestad; Wanda K. Denson-Low 4,943,014 7/1990 Harwood et al. ....................... 244/169 57) ABSTRACT FOREIGN PATENT DOCUMENTS An apparatus and method for translating a spacecraft (10) from an injection orbit (16) about a central body (10) to 0047211 3/1982 European Pat. Off. ............... 244/169 geosynchronous orbit (18) in a time efficient manner.
  • Closed Form Relegation Versus Expansions of Elliptic Motion

    Closed Form Relegation Versus Expansions of Elliptic Motion

    Hindawi Publishing Corporation Mathematical Problems in Engineering Volume 2013, Article ID 570127, 11 pages http://dx.doi.org/10.1155/2013/570127 Research Article Averaging Tesseral Effects: Closed Form Relegation versus Expansions of Elliptic Motion Martin Lara,1 Juan F. San-Juan,2 and Luis M. López-Ochoa2 1 C/Columnas de Hercules 1, San Fernando, Spain 2 UniversidaddeLaRioja,Logrono,˜ Spain Correspondence should be addressed to Juan F. San-Juan; [email protected] Received 7 February 2013; Accepted 26 March 2013 Academic Editor: Antonio F. Bertachini A. Prado Copyright © 2013 Martin Lara et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Longitude-dependent terms of the geopotential cause nonnegligible short-period effects in orbit propagation of artificial satellites. Hence, accurate analytical and semianalytical theories must cope with tesseral harmonics. Modern algorithms for dealing analytically with them allow for closed form relegation. Nevertheless, current procedures for the relegation of tesseral effects from subsynchronous orbits are unavoidably related to orbit eccentricity, a key fact that is not enough emphasized and constrains application of this technique to small and moderate eccentricities. Comparisons with averaging procedures based on classical expansions of elliptic motion are carried out, and the pros and cons of each approach are discussed. 1. Introduction rate to the mean motion of the orbit and hence converges very slowly, except for low-altitude orbits. Another drawback Soon after Brouwer’s dream of a closed form solution to the of the standard algorithm, is that it assumes nonresonance artificial satellite theory (AST) to higher orders was achieved conditions and finds a gradual deterioration in the solution forthemainproblemofAST[1–3], the progress in mathemat- when approaching synchronous condition [9].
  • OUTER SPACE TREATY Tracing the Journey

    OUTER SPACE TREATY Tracing the Journey

    FIFTY YEARS OF THE OUTER SPACE TREATY Tracing the Journey FIFTY YEARS OF THE OUTER SPACE TREATY Tracing the Journey Editor Ajey Lele INSTITUTE FOR DEFENCE STUDIES & ANALYSES NEW DELHI PENTAGON PRESS Fifty Years of the Outer Space Treaty: Tracing the Journey Editor: Ajey Lele First Published in 2017 Copyright © Institute for Defence Studies and Analyses, New Delhi ISBN 978-81-8274-948-1 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without first obtaining written permission of the copyright owner. Disclaimer: The views expressed in this book are those of the authors and do not necessarily reflect those of the Institute for Defence Studies and Analyses, or the Government of India. Published by PENTAGON PRESS 206, Peacock Lane, Shahpur Jat New Delhi-110049 Phones: 011-64706243, 26491568 Telefax: 011-26490600 email: [email protected] website: www.pentagonpress.in In association with Institute for Defence Studies and Analyses No. 1, Development Enclave, New Delhi-110010 Phone: +91-11-26717983 Website: www.idsa.in Printed at Avantika Printers Private Limited. Contents Foreword vii About the Contributors xi Introduction 1 SECTION I DEBATING OUTER SPACE TREATY 1. Evolution of the Outer Space Treaty 13 Ram S. Jakhu 2. Outer Space Treaty and International Relations Theory: For the Benefit of All Mankind 20 Joan Johson Freese 3. Outer Space Treaty: An Appraisal 24 G.S. Sachdeva 4. Relevance and Limitations of Outer Space Treaty in 21st Century 48 Ranjana Kaul 5.
  • Space Security Index

    Space Security Index

    SPACE SECURITY 2011 www.spacesecurity.org SPACE 2011SECURITY SPACESECURITY.ORG iii FOR PDF version use this Library and Archives Canada Cataloguing in Publications Data Space Security 2011 ISBN : 978-1-895722-87-1 ISBN : 978-1-895722-87-1 © 2011 SPACESECURITY.ORG Edited by Cesar Jaramillo Design and layout: Creative Services, University of Waterloo, Waterloo, Ontario, Canada Cover image: The International Space Station is featured in this photograph taken by an STS-130 crew member on space shuttle Endeavour after the station and shuttle began their post-undocking relative separation on 19 February 2010. Image credit: NASA. Printed in Canada Printer: Pandora Press, Kitchener, Ontario First published August 2011 Please direct inquires to: Cesar Jaramillo Project Ploughshares 57 Erb Street West Waterloo, Ontario N2L 6C2 Canada Telephone: 519-888-6541, ext. 708 Fax: 519-888-0018 Email: [email protected] Governance Group Gérard Brachet Institute de l’Air et de l’Espace Peter Hays Eisenhower Center for Space and Defense Studies Dr. Ram Jakhu Institute of Air and Space Law, McGill University William Marshall NASA – Ames Research Center Paul Meyer The Simons Foundation John Siebert Project Ploughshares Dana Smith Foreign A airs and International Trade Canada Ray Williamson Secure World Foundation Advisory Board Richard DalBello Intelsat General Corporation Theresa Hitchens United Nations Institute for Disarmament Research Dr. John Logsdon The George Washington University Dr. Lucy Stojak HEC Montréal Project Manager Cesar Jaramillo Project Ploughshares Table of Contents TABLE OF CONTENTS PAGE 1 Acronyms PAGE 7 Introduction PAGE 10 Acknowledgements PAGE 11 Executive Summary PAGE 27 Chapter 1 – The Space Environment: this indicator examines the security and sustainability of the space environment with an emphasis on space debris, the potential threats posed by near-Earth objects, and the allocation of scarce space resources.
  • Space Security Index 2013

    Space Security Index 2013

    SPACE SECURITY INDEX 2013 www.spacesecurity.org 10th Edition SPACE SECURITY INDEX 2013 SPACESECURITY.ORG iii Library and Archives Canada Cataloguing in Publications Data Space Security Index 2013 ISBN: 978-1-927802-05-2 FOR PDF version use this © 2013 SPACESECURITY.ORG ISBN: 978-1-927802-05-2 Edited by Cesar Jaramillo Design and layout by Creative Services, University of Waterloo, Waterloo, Ontario, Canada Cover image: Soyuz TMA-07M Spacecraft ISS034-E-010181 (21 Dec. 2012) As the International Space Station and Soyuz TMA-07M spacecraft were making their relative approaches on Dec. 21, one of the Expedition 34 crew members on the orbital outpost captured this photo of the Soyuz. Credit: NASA. Printed in Canada Printer: Pandora Print Shop, Kitchener, Ontario First published October 2013 Please direct enquiries to: Cesar Jaramillo Project Ploughshares 57 Erb Street West Waterloo, Ontario N2L 6C2 Canada Telephone: 519-888-6541, ext. 7708 Fax: 519-888-0018 Email: [email protected] Governance Group Julie Crôteau Foreign Aairs and International Trade Canada Peter Hays Eisenhower Center for Space and Defense Studies Ram Jakhu Institute of Air and Space Law, McGill University Ajey Lele Institute for Defence Studies and Analyses Paul Meyer The Simons Foundation John Siebert Project Ploughshares Ray Williamson Secure World Foundation Advisory Board Richard DalBello Intelsat General Corporation Theresa Hitchens United Nations Institute for Disarmament Research John Logsdon The George Washington University Lucy Stojak HEC Montréal Project Manager Cesar Jaramillo Project Ploughshares Table of Contents TABLE OF CONTENTS TABLE PAGE 1 Acronyms and Abbreviations PAGE 5 Introduction PAGE 9 Acknowledgements PAGE 10 Executive Summary PAGE 23 Theme 1: Condition of the space environment: This theme examines the security and sustainability of the space environment, with an emphasis on space debris; the potential threats posed by near-Earth objects; the allocation of scarce space resources; and the ability to detect, track, identify, and catalog objects in outer space.
  • Red De Comunicaciones Satelitales

    Red De Comunicaciones Satelitales

    Red de Comunicaciones Satelitales. Luis Andreula. 1 INTRODUCCION. La presente investigación tiene como finalidad la comprensión y el estudio de la Red de Comunicaciones Satelitales, en el mismo estudiaremos la historia de los satélites artificiales, los tipos de satélites según la misión que cumplan y su tipo de orbita. Entendiendo por satélite como un repetidor radioeléctrico ubicado en el espacio, que recibe señales generadas en la tierra, las amplifica y las vuelve a enviar a la tierra, ya sea al mismo punto donde se origino la señal u otro punto distinto. La red satelital consiste de un transponder (dispositivo receptor transmisor), una estación basada en tierra que controlar su funcionamiento y una red de usuario, de las estaciones terrestres, que proporciona las facilidades para transmisión y recepción del tráfico de comunicaciones, a través del sistema de satélite. Posteriormente analizaremos a fondo los satélites orbitales y geoestacionarios, los patrones orbitales, las orbitas geosincronas, el ángulo de elevación y el azimut. Luego estudiaremos las clasificaciones orbitales, espaciamiento y asignaciones de frecuencia, los patrones de radiación y los modelos de enlace del sistema satelital. Para finalizar estudiaremos los parámetros del sistema satelital, el sistema de comunicación Globalstar, las agencias espaciales, la industria aeroespacial y los países con capacidad de lanzamiento de satélites. 2 RED DE COMUNICACIONES SATELITAL. 3 Historia de los Satélites. La primera representación ficticia conocida de un satélite artificial lanzado a una órbita alrededor de la Tierra aparece en un cuento de Edward Everett Hale, The Brick Moon („la luna de ladrillos‟). El cuento, publicado por entregas en Atlantic Monthly, se inició en 1869.
  • Satélite Artificial 1 Satélite De Comunicaciones 10

    Satélite Artificial 1 Satélite De Comunicaciones 10

    Contenidos Artículos Satélite artificial 1 Satélite de comunicaciones 10 Clasificación por sincronía 14 Órbita geosíncrona 14 Órbita geoestacionaria 15 Clasificación por centro 17 Órbita heliocéntrica 17 Órbita geocéntrica 17 Clasificación por altitud 19 Órbita baja terrestre 19 Órbita media terrestre 20 Referencias Fuentes y contribuyentes del artículo 21 Fuentes de imagen, Licencias y contribuyentes 22 Licencias de artículos Licencia 23 Satélite artificial 1 Satélite artificial Un satélite es cualquier objeto que orbita alrededor de otro, que se denomina principal. Los satélites artificiales son naves espaciales fabricadas en la Tierra y enviadas en un vehículo de lanzamiento, un tipo de cohete que envía una carga útil al espacio exterior. Los satélites artificiales pueden orbitar alrededor de lunas, cometas, asteroides, planetas, estrellas o incluso galaxias. Tras su vida útil, los satélites artificiales pueden quedar orbitando como basura espacial. Antecedentes históricos Satélite artificial Swift. La primera representación ficticia conocida de un satélite artificial lanzado a una órbita alrededor de la Tierra aparece en un cuento de Edward Everett Hale, The Brick Moony dirigido por Hugo Liscano (La luna de ladrillos). El cuento, publicado por entregas en Atlantic Monthly, se inició en 1869.[1] [2] El objeto del título se trataba de una ayuda para la navegación pero que por accidente fue lanzado con personas en su interior. La idea reaparece de nuevo en Los quinientos millones de la begún de Julio Verne de 1879. En este libro, sin embargo, se trata de un resultado inintencionado del villano al construir una pieza de artillería gigante para destruir a sus enemigos, comunicando al proyectil una velocidad superior a la pretendida.
  • Minimum Time Orbit Raising of Geostationary Spacecraft by Optimizing Feedback Gain of Steering Law

    Minimum Time Orbit Raising of Geostationary Spacecraft by Optimizing Feedback Gain of Steering Law

    Trans. JSASS Aerospace Tech. Japan Vol. 17, No. 3, pp. 363-370, 2019 DOI: 10.2322/tastj.17.363 Minimum Time Orbit Raising of Geostationary Spacecraft by Optimizing Feedback Gain of Steering Law By Kenji KITAMURA,1) Katsuhiko YAMADA,2) and Takeya SHIMA1) 1) Advanced Technology R&D Center, Mitsubishi Electric Corporation, Amagasaki, Japan 2) Graduate School of Engineering, Osaka University, Osaka, Japan (Received June 23rd, 2017) This study considers the minimum time orbit-raising problem of geostationary spacecraft with low-propulsion thrusters. This problem is equivalent to determining an appropriate thrust direction during orbit raising. This study proposes a closed- loop thruster steering law that determines the thrust direction based on the optimal feedback gains and control errors of each orbital element. The feedback gains of the steering law are assumed to be the functions of orbital elements and are optimized by a meta-heuristic method. The orbital semi-major axis, eccentricity, and inclination are considered as independent variables for expressing the gains. Numerical simulations show that whichever orbital elements is selected as an independent variable, the same performances are obtained. Therefore, regardless of the initial orbital elements, by selecting the independent variable appropriately, the proposed method can always solve the minimum time orbit-transfer problem. Key Words: Orbit Raising, Geostationary Orbit, Low-Propulsion Thruster, Optimal Control Nomenclature Subscripts 0 : initial : semi-major axis : final : eccentric anomaly : normal direction in Local Vertical Local � : eccentricity � Horizontal (LVLH) coordinates � : eccentricity vector � : radial direction in LVLH coordinates � : magnitude of thruster force : transversal direction in LVLH coordinates ������� � g : gravitational acceleration of Earth at sea � � � level 1.
  • Ground Observations of Falcon-9 Second Stage

    Ground Observations of Falcon-9 Second Stage

    GROUND OBSERVATIONS OF FALCON-9 SECOND STAGE ORBITAL VENTING/THRUSTING AS AID FOR INTERPRETING UNUSUAL VISUAL FEATURES OF MYSTERIOUS ‘ZUMA’ LAUNCH FINAL DRAFT March 20, 2018 James Oberg [email protected] PROBLEM AND APPROACH • 1 Classified payload Zuma launched, results not disclosed • 2 Accidental imaging of second stage venting by MANY observers • 3 SpaceX disclosure of ‘normal’ venting procedure is scanty • 4 However, some past launches had similar venting imagery • 5 Detailed study of images and descriptions can possibly help characterize spacecraft activities including anomalies • 6. Random nature of rare enabling conditions will always make such opportunities for insights rare and unpredictable • 7. All the more motivation to jump on such literally heaven-sent serendipitous opportunities whenever they are discovered • 6. Assessment of witness misperceptions [based on a known visual stimulus] helps understand reliability of other sky observations • 7 Two more stage2 burn/dump observations occurred the following month and those events are incorporated into this overview report • 8. All five ‘analogous plumes’ have detailed focused reports to be examined 2 Launch sequence of events & rumors • LAUNCH • Mission event discussion: https://forum.nasaspaceflight.com/index.php?topic=44175.0 • Mission results analysis https://forum.nasaspaceflight.com/index.php?topic=43976.0 • Launch video https://youtu.be/iS644RQYKTw • S2 debris warning zone https://forum.nasaspaceflight.com/assets/43976.0/1468540.jpg 3 The double-spiral “Khartoum Clue”