Technical Review

COMSAT Technical Review Volume 21 Number 2, Fall 1991 Advisory Board Joel R. Alper Joseph V. Charyk COMSAT TECHNICAL REVIEW John V. Evans Volume 21 Number 2, Fall 1991 John. S. Hannon Editorial Board Richard A. Arndt, Chairman S. Joseph Campanella 273 FOREWORD: MAKING REALITY OUT OF A VISION Dattakumar M. Chitre P. J. Madon William L. Cook 275 EDITORIAL NOTE Calvin B. Cotner S. B. Bennett AND G. Hyde Allen D. Dayton Russell J. Fang Ramesh K. Gupta INTELSAT VI: From Spacecraft to Satellite Operation Michael A. Holley 279 ENSURING A RELIABLE SATELLITE Edmund Jurkiewicz C. E. Johnson, Ivor N. Knight R. R. Persinger, J. J. Lemon AND K. J. Volkert George M. Metze 05 INTELSAT VI LAUNCH OPERATIONS, DEPLOYMENT, AND BUS Alfred A. Norcott IN-ORBIT TESTING Hans J. Weiss L. S. Virdee, T. L. Edwards, A. J. Corio AND T. Rush Amir I. Zaghloul ast Editors Pier L. Bargellini, 1971-1983 39 IN-ORBIT RE TEST OF AN INTELSAT VI SPACECRAFT Geoffrey Hyde, 1984-1988 G. E. G. Rosell, B. Teixeira, A. Olimpiew , B. A. Pettersson AND Editorial Staff MANAGING EDITOR S. B. Sanders Margaret B. Jacocks 391 DESIGN AND OPERATION OF A POST-1989 INTELSAT TTC&M TECHNICAL EDITOR EARTH STATION Barbara J. Wassell PRODUCTION R. J. Skroban AND D. J. Belanger Barbara J. Wassell 11 INTELSAT COMMUNICATIONS OPERATIONS Virginia M. Ingram M. E. Wheeler N. Kay Flesher Margaret R. Savane 431 INTELSAT VI SPACECRAFT OPERATIONS CIRCULATION G. S. Smith Merilee J. Worsey Non-INTELSAT VI Papers COMSAT TECHNICAL REVIEW is published by the Communications Satellite 455 MULTILINGUAL SUBJECTIVE METHODOLOGY AND EVALUATION OF Corporation (COMSAT). Subscriptions, which include the two issues published for a LOW-RATE DIGITAL VOICE PROCESSORS calendar year. are: one year, $20 U.S.; two years, $35; three years, $50; single copies, S. Dimolitsas, F. L. Corcoran , M. Baraniecki AND J. G. Phipps, Jr. $12; article reprints, $3. Overseas airmail delivery is available at an additional cost of $18 per year. Make checks payable to COMSAT and address to: Records Department. 473 OBJECTIVE ASSESSMENT METHODOLOGY AND EVALUATION OF Communications Satellite Corporation, 22300 Comsat Drive, Clarksburg, MD 20871- LOW-RATE DIGITAL VOICE PROCESSORS 9475, U.S.A. S. Dimolitsas, F. L. Corcoran , M. Baraniecki AND J. G. Phipps, Jr. ISSN 0095-9669 495 TRANSLATIONS OF ABSTRACTS FRENCH 495 SPANISH 499 COMMUNICAHONS SATELLITE CORPORATION 1991 COMSAT IS A TRADE MARK AND SERVICE MARK 503 PAPERS SCHEDULED FOR PUBLICATION IN THE. CTR INTELSAT VI OF 9I IE COMMUNICATIONS SATELLITE CORPORATION SERIES ii iii Foreword: Making reality out of a vision PIERRE J. MADON The design, manufacture, and test of the INTELSAT VI satellite presented a real challenge, for several reasons. INTELSAT VI is the heaviest commercial telecommunications satellite placed in geostationary orbit to date, with a mass in excess of 4,000 kg. It is also physically quite large, particularly when deployed-some 11.6 to in height and 3.6 m in diameter. In addition, INTELSAT VI pushes the limit of technology for spin-stabilized satellites, including deployment of a solar generator drum to achieve the required power, and use of "superspin" to ensure dynamic stability throughout the transition from transfer orbit to geostationary orbit. The satellite also carries the most complex payload to date, with 48 transponders, sixfold frequency reuse at C-band through a combination of polarization and coverage pattern isolation, and on-hoard dynamic switching of digital traffic between antenna beams (satellite-switched time-division multiple access [Ss-TDMAj). The launch of the INTELSAT VI series encountered several setbacks that had to be overcome. The initial plan called for three of the five satellites to be launched using NASA's Space Transportation System (the Shuttle), and two using the Ariane 4 launch vehicle. However, the Shuttle Challenger disaster in January 1986, followed by failure of an Ariane vehicle in May of the same year, resulted in substantial delay of the INTELSAT vt program. The subsequent plan entailed launching three satellites with Ariane 4 and two with Titan III vehicles. Although one Titan launch left INTELSAT 603 stranded in low earth orbit, and currently the subject of a reboost mission, the other four satellites were successfully placed in geostationary orbit, beginning with the first launch on October 27, 1989. Despite these many challenges, all five INTEISAT VI satellites are functioning so well that it could be considered miraculous! In reality, their success is the result of a perfect job done primarily by the satellite manufacturer, Hughes Aircraft Company, with significant assistance from both COMSAT and INTELSAT. This and the previous two issues of COMSAT Technical Review document that achievement. 273 274 COMSAT TECHNICAL REVIEW VOLUME 21 NUMBER 2, PALL 1991 Pierre J. Madon received the Diploma of Engineer Editorial Note from the Ecole Polytechnique, Paris, in 1955; the Auditor ENSAE from the Engineering School of Aeronautics and S. B. BENNETT, Guest Editor, INTELSAT Astronautics, Paris, in 1957; and an M.S. in electrical G. HYDE, Associate Guest Editor , COMSAT engineering form Harvard University in 1958. From 1957 to 1986, he was with Nord Aviation (later Aerospatiale) This is the third issue of the COMSAT Technical Review (CTR) dedicated to as Program Manager for the launch vehicle DIAMANT, the INTELSAT VI satellite and system. Because of the importance and complex- Head of the Departments of Analog Computers, Digital Computers, and Electronic Equipment Designers; and ity of the INTELSAT VI satellite and its associated system operation, three Program Manager for the SYMPHONIE telecommunica- issues of CTR are needed to fully document the process leading to its very tions satellite and the Ariane launch vehicle. He subse- successful implementation. These issues cover the subject from concept, through quently served as Director of the Aerospatiale plant in Les Mureaux, France, and design and test, to in-orbit operation. Related fourth and fifth issues will as General Manager of EUROSATELLITE. From 1983 to 1986, he was Spice Pro- address system applications and the implementation of satellite-switched time- grams Director for Aero.spatiale. division multiple access (SS-TDMA). Compilation of this series is a joint effort Mr. Madon joined INTELSAT in 1986 as Senior Director of the Engineering of COMSAT and INTELSAT, including co-editors from each organization. Division. He was promoted to Vice President, INTELSAT Engineering and Research, The first issue in the CTR INTELSAT VI series* described the overall devel- in 1992. His tenure at INTELSAT h as encompassed the launch of the INTELSAT VI opment process, as well as system planning, specification of the spacecraft series of satellites and the deployment and initiation of the INTELSAT VI system, bus and communications payload, and the design for SS-TDMA and frequency- operation, and services. The INTELSAT VII and INTELSAT K programs were also division multiple access (FDMA) services. The second issue focused on the initiated, and their procurement is well under was. In addition, the FOS procurement design of the INTELSAT VI spacecraft and its communications payload, dealing program has been initiated. Mr. Madon is a member of the AIAA. with the design of the spacecraft bus; the attitude and payload control system; a design overview and description of the communications payload; the design, implementation, and testing of the antenna system; and the design and implementation of the on-board SS-TDMA package. This third issue in the INTELSAT VI series covers a wide range of topics, including measures taken to ensure a reliable satellite; the launch, deployment, and in-orbit testing phases; and operation of the satellite in orbit. The first paper deals with the execution of an extended in-house monitoring program, from unit-level design and analysis through development and all phases of the extensive and complex test plan. The second paper details the planning and implementation of an INTELSAT VI launch, as well as post-launch operations such as deployment, attitude, and in-orbit bus tests. In-orbit RE testing of the payload from a telemetry, tracking, command, and monitoring (TTC&M) earth station, including measurements of antenna patterns, transpon- der performance, and telemetry, command, and ranging subsystem performance are discussed in the third paper. The design, implementation, and operation of an INTELSAT post-1989 TTC&M earth station, and the associated special-purpose complex, are the subject of paper four. Paper five covers *Refer to pages 503 through 507 of this issue for a listing of the papers scheduled for publication in this series. Papers on other topics may also be included. 275 276 COMSA I TECHNICAL. REVIEW VOLUME 21 NUMBER 2. FALL. 1991 EDITORIAL. NOTE 277 the management and operation of the communications payloads on-station, Simon B. Bennett received it B.E.E. from Ciro College including interfacing with the INTELSAT vi networks and bringing new ser- of New York in 1959 and an M.E. E. front New York Uni ver- vices, carriers, and earth stations on line. The last paper in this issue deals with sity in 1961. His career. which spans the entire histarv of the upgrading and use of the spacecraft operations resources required for the conunmtications satellites, began with work on the first INTELSAT VI fleet, especially increasing the level of automation and data TELS'IAR satellite program at Bell Telephone Laborato- ries firnn 1959 to 1963. He continued in this field train processing capabilities and making the transition to a centralized telecom- 1961 to 1974 at COMSAT, where he contributed to the manding mode. success of satellite programs from Early Bird to Presented in a related fourth issue on the INTELSAT system and applica- INTELSAT /V. Since 1974 he has been at INTELSAT where tions will be papers on earth station considerations, as well as on digital.

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