The Space Congress® Proceedings 1976 (13th) For The New Horizon

Apr 1st, 8:00 AM

The Symphonie System And Its Utilizations

A. Langemeyer Symphonie Executive Comittee

F. Pene Symphonie Executive Comittee

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Scholarly Commons Citation Langemeyer, A. and Pene, F., "The Symphonie System And Its Utilizations" (1976). The Space Congress® Proceedings. 2. https://commons.erau.edu/space-congress-proceedings/proceedings-1976-13th/session-8/2

This Event is brought to you for free and open access by the Conferences at Scholarly Commons. It has been accepted for inclusion in The Space Congress® Proceedings by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. THE SYMPHONIE SYSTEM AND ITS UTILIZATIONS

A. LANGEMEYER

F. PENE

SYMPHONIE EXECUTIVE COMITTEE

of In 1967, the Governments of the Federal Republic ABSTRACT a Germany and France decided to jointly develop telecommunication satellite system and to launch After the successful completion of the SYMPHONIE the two satellites. One year later the French-German project development phase, which resulted in consortium CIFAS, in which the French injection into of two flight industrial Societe Nationale A£rospatiale (SNIAS), models (December 1974 and August 1975), the French- companies -CSF, Society Anonyme de Telecommunication German programme is carrying on in the aim of Thomson the German companies Messerschmitt- setting up and performing a great number of diffe­ (SAT) and of (MBB), Siemens, AEG-Telefunken parti­ rent experiments demonstrating the capability Bttlkow-Blohm all charged with the development and cons­ this 4/6 GHz satellite system to comply with cipate, was the satellites. kinds of utilizations. truction of by the ELDO program of the Based upon the capability and the performances The discontinuance which had originally been des­ offered by the spacecrafts (three-axis-stabilized) II launcher, SYMPHONIE satellites, and and their telecommunication payload (two repeaters tined to launch the two spot to the NASA launcher Thor each with 90 MHz bandwidth associated with two the subsequent change of only half a year. beam transmitting antennae) together with several 2914 led to a delay between NASA and stations (primary stations, secondary trans­ Thanks to the good cooperation earth and SYMPHONIE on stations) there is an ambitious programme its contractors on the one side, portable technical the main categories of which are the other side the initial difficult of experiments, trans­ problems - such as vibration specifications, listed below : rules- fer orbit parameters and launch site security - experimental telecommunications programme inclu­ could be solved. with ding the French-German tests and other tests ; at 2.39 hrs (GMT) the first or by foreign countries (e.g. ISRO-programme) On December 19, 1974 flight model wa

8-19 (90 MHz) associated with two transmission antennae satellite's transponder is fully controlled, and providing two dedicated earth receiving areas with therefore no longer only operates in the linear an EIRP bether than 29 dBW (edge). range of its characteristic curve, the optimiza­ tion of the transmission parameters is necessary b) The based upon two primary sta­ in order to optimally use bandwidth and satellite tions (so called standard) located in Raisting power for a given minimum transmission quality. (W-G) and Pleumeur Bodou (p) offering identical The influence of the number of carriers, their performances such as a G/T = 31.5 dB/°£ (with a distance from each other and the transmitting dish diametre of 16 ra), uncooled parametric pream­ power, which determines the distance plifiers and 3 KW transmitter. from the operating point to the saturation point, on In addition, several stations have been developped the signal-to-noise ratio of the telephone channel for the purpose of the utilization plan of Sympho- was experimentally determined. For flight model nie. Among these stations, we will notice for ins­ 1 these measurements, in multi-carrier operation, tance : resulted - four in a capacity of 768 channels for the 8,8 m diametre receiving stations (G/T = transponder 26.5 dB/°l) dedicated b, and of 624 channels for the trans - to the Educational TV pro­ ponder d. The gramme in Africa, different capacity of the two transponders is a result of their - one 5 m diametre T/R station (G/T = 20 different fre­ dB/°K, quency plans. The frequencies of the 250 W transmitter) used to experiment digital operation telephone carriers were therefore arranged in such a way technics and visiophonie (teleconference that system), intermodulation products fall together with operation carriers. The cross-talk attenuation - one 3 m diametre T/R station providing was one voice not allowed to fall below 60 channel + telex (or a fac-simile transmission). dB, A further test series Other stations are under development dealt with the verification by the time of transmissions of television being (ex : two multipurpose T/R station). and sound channels with optimized transmission parameters. The trans­ mission of a single TV signal according to speci­ fications could be valued with quality 3. TELECOMMUNICATION TEST PROGRAM grade 5, i.e. the highest reachable. During further tests one TV channel and. two sound channels 3.1. Verification of the telecommunication were trans­ speci­ mitted without reciprocal interference. fications of the satellite The transmission of two TV channels still reached quality grade 4. This verification consists of ten test series : 1 - the satellite's EIRP 3.3. Newer transmission procedures 2 - receiving sensitivity of the satellite (G/T) 3 - bandpass characteristic of the transponders After conclusion 4 - of the above-mentioned measure­ group delay behavior of the transponders ments transmission 5 - stability procedures are to be tested of frequency conversion with the aid of SYMPHONIE 6 - stability of amplification in order to increase the transmission capacity of satellite links. measuring of nonlinear distortion : 7 - level of intermodulation products This year, for example, 8 - AM/PM conversion a French-developed pro­ cedure, by which 30 analog channels are to be put 9 - intelligible -crosstalk together 10 into 6 single channels plus two 12- - EIRP, level and frequency stability of the channel beacons systems or one 24-channel system respec­ tively, is to be tested. The main purpose of this verification is to prove To that improve the transmission of TV and sound the satellite's properties, which had been channels measured digital procedures for the transmission on the ground, did not change while in of TV signals orbit. These measurements are to be tested. The procedure of were carried out by the putting sound channels Pleumeur Bodou and Raisting and a picture channel into stations which are not one carrier is to be examined special measuring stations just as well as the but regular operational integration of sound channels stations. In some measuring into the sync pulse series for example - or by digital coding into such as the measuring of the horizontal blanking the transponder bandpass interval between picture informations. characteristic - the Further influences of the ground tests are to deal with video stations on the measuring telephony (picture results could not be telephone) and with the transmission completely eliminated. The observance of four 15 of the spe­ kHz sound channels concentrated in 24 telephone cified values could therefore only be confirmed channel carri ers. within the scope of the measuring accuracy. For the future it is also planned to use SYMP T -ONTE 3.2, Optimization of the transmission parameters for the testing of TDMA procedures. However, the development of the ground equipment has not yet In this test series transmission tests with tele­ prospered far enough to set up a concrete test phone, telex and data channels in single and multi- program. carrier operation are carried through. Since the

8-20 3.4. International cooperation tional TV and mobile telephone small station (j^3m), - DGLR Symposium (nov. 75) : telephone transmission. Besides the experiments described sofar, which were mainly executed by Germany and France, mea­ In the mean time, SYMPHONIE has also been used to suring and transmission tests are also to be transmit special events such as : carried out by other countries. Among other things, the capacity of one transponder was made available - alive transmission of the launch of Soyouz space­ to India for such purposes for a period of two craft (Apollo-Soyouz mission in Juil. 75), years. One of the two flight models will therefore - visit of the french President in Moscow (oct. 75). be moved from its actual position at 11,5 degrees West to a position at approximately 50 degrees East. 6. EDUCATIONAL AND HUMANITARY UTILIZATIONS

4. TECHNOLOGICAL TESTS WITH THE SATELLITE The purpose of such utilizations is to demonstrate the ability of a space telecommunications System Besides the telecommunication tests, experiments to solve various problems in the field of mass with the space technological subsystem of the and also to help for in case of disaster satellite are carried out. relief and/or peace keeping operations.

4.1. Apogee motor - For educational experiments, SYMPHONIE has deve­ lopped four TV reception stations. The first one The liquid apogee motor used for SYMPHONIE repre­ is now installed and operated in in sented the first application of liquid propulsion order to feed this country with educational TV for kick motors by spinning satellites. The exact programmes produced in France and Germany in power had to be determined, and the problem of the addition with those produced by Ivoirians. The spin movement of the liquid-propellant-filled tank remaining stations are planned to be installed in had to be observed. The flight measurements brought the near future in other african countries. fully satisfactory results. In comparing transfer - A small air transportable 3 m station (shown in and primary orbit the velocity increments reached telecom 75) has been provided to UN for several for FM1/FM2 were measured to be 1473.5/1466.6 m/s; months in order to experiment the ability and the predicted were 1473.0/1465.3 m/s. Thus the devia­ interest to provide an immediate and direct commu­ tion amounted to + 0.03/+ 0.09 %. nication service between HQ in Geneva and New-York and a peace keeping mission located in Middle-East. 4.2. Hot gas system - In addition several and various teleconferences will be held through SYMPHONIE for the purpose of The also newly developed biliquid attitude control Culture, Education, Science... (i.e. cooperation system is still to be measured as to its real per­ with Canada). formance in orbit. Investigations on the minimum realizable thrust impulses led to switching times of 0.016 s. This thrust system is therefore also 7. PREOPERATIONAL UTILIZATIONS suited for attitude control, especially for shif­ ting the pitch axis. The intent is to take opportunity of SYMPHOTTIF to perform experiments complying with all kinds of 4.3. Static infrared horizon sensor constraints and requirements of operational service in order to get all actual results which can be Due to inititial procurement difficulties a static used later to size and set up a future real service. infrared horizon sensor for the alignment of the Two projects will enter in operation this year : satellite to the earth was also developed in the framework of the project. Measurement results in­ - the french PTT will use SYMPHONIE to relay the dicated a dispersion of less than + 0.03 degrees. telephone communications between France and La The winter/summer drift was measured to be 0.28 Reunion island (juil. 76), degrees. - West Germany will transmit, through SYMPHONIE, radioprogrammes to a radiobroadcasting station lo­ cated in Kigali (Rwanda, Africa). 5. DEMONSTRATIONS

The world-wide promotion of the system has been 8. CONCLUSION made through active demonstrations in several When considering the present stage of the SYMPriOnlE occasions such as : operations and looking forwards the future utili­ zation plan, there is no doubt in the real need - Le Bourget Air-show (Mai 75) where two stations for such an experimental system available, under allowed the demonstration of the "visiophonie" very limited constraints, to perform any kind of system developped by CNET and the educational TV experiments in the field of the space communica- reception, .tions. - Telecom 75 (oct.75) where the multiple capabili­ In addition, the flight proven mission performances ty of SYMPHONIE has been shown thanks to three of the two SYMPHONIE satellite$clearly demonstrate simultaneous demonstrations : visiophonie, educa­ the european know how in the technoloay of space Communication systems.

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