Syncom C Press Kit

8/7/2019 Syncom C Press Kit

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/. !NATIC NAL AERONAUTICS AND SPACE ADMINISTRATION TELS WO 2-4155WASHINGTON, D C 20546 WO 3-6925

- FOR RELEASE: Thursday, IMMEDIATEAugust 13 , 1964RELEASE 0o: 64-193NASA'S SYNCOM CSATELLITE IS SETFOR LAUNCHING

An attempt to achieve the world's first truly stationaryorbit will be made by the National Aeronautics and SpaceAdministration when it launches Syncom C, the third synchronous-orbit communications satellite, from Cape Kennedy aboard a ThrustAugmented Delta (TAD) launch vehicle no earlier than Aug. 18.


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-2- -"A..A -uortedn the Syncom program by the U.S. Army

SatelliLte Communications Agency, Fort Monmouth, N.J., which pro-vides the surface stations in the United States and overseas.

Work is underway to make it possible to transmit the 1964Olympic~s from Japan via Syncom to television viewers in the UnitedStates. Japan is installing the transmitting equipnment and anantenna at ihe U.I Navy's Point Mugu, Calif., facility is beingmodified to receive the transmissions from Japan in October.

Synctnu C also will be able to transmit two-way telephoneconversations as well as teletype and facsimile pictures.


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When the third stage is fired it places the spacecraft ina transfer orbit which has a minimum altitude of 700 miles, amaximum altitude of 22,900 miles and is about 16 degrees offalignment with the Equator.

After third stage burn, the spacecraft will coast for about5J hours to its first apogee over the Indian Ocean.

About 11 hours after first apogee the spacecraft, now separatedfrom the third stage, will be over tha West Coast of South Americaat its second apogee. Here the satellite will be re-aligned withan attitude change of a out 10 degrees, making it more parallel with


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With this couranand the satellite will be kicked out of Lhelooping elliptical orbit and put into a circular, synchronousorbit. It will then be in alignment with the Equator provided allprevious maneuvers were successful.

After a few hours, data from Syncom will provide enough in-formation to determine whether the spacecraft is drifting east orwest and at what rate. If it is moving east at the proper speed nocorrections will be made. Otherwise a hydrogen peroxide gas Jetwill be fired from a ground station to provide the desired driftrate about seven degrees a day.


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Earlier Syncoms, I and II, were launched Feb. 14, andJuly 26, 1963, respectively. Syncom I achieved synchronous orbitbut all communications with it ceased about 20 seconds after theapogee-kick motor was fired. Syncom II achieved a synchronousorbit and has worked flawlessly ever since. It is now being movedover the Pacific from its original on-station position at 55 degreeswest over Brazil.

Both these satellites move above and below the Equator in afigure eight pattern rather than remaining over one point on the


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-6 -

l4

SYNCOM C TECHNICAL INFORMATIONContents

Tit.e PageChoice of Equatorial Orbit .7....Syncom C Improvenents . . . . . . . . . . . 7


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Cloice of Equatorial OrbitThe choice of a synchronous equatorial orbit for Syncom C

came about for the following reasons:

1. Such an orbit is ideal for a comminications satellitesystem as well as being the logical next step from Syncom II.

2. After the successful operation of Syncom II, the TAD,not available for the original Syncom project plans, made avail-able the extra booster power and thrust of the new X-258 upperstage to attempt a stationary orbit at relatively little additionalcost.


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-9-Antennas include a slotted array antenna for communications

transmission, a slotted dipole for communications receiving and fourwhip antennas in a turnstile arrangement for telemetry and command.

Syncom has a passive temperature control system. That is,adequate temperature control is achieved by the design and materialsused on the external surface and by properly insulating subsystemequipment.

Electronics


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-10-

The receiver then drives one of the two transmitters, thetraveling wave tube of which delivers two watts to the antennaat a frequency of about 1815 me. The transmitter also provides a100 milliwatt tracking beacon signal at 1820 me.

The total transponder power consumption is 15 watts. Atransponder weighs eight pounds, including the traveling wave tubeand high voltage power supply.

Besides acting as a beacon and a communications transponder,Syncom's communications system also will transpond signals to measure


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;ot 14'2) .'c con.m.anu, r' celvers are identical. Each has4its own raixer, IF amplifier and AM detector. The hybrid network

allows command receivers and telemetry systems to share the turn-stile antenna which is a minimum of -4.5 db gain. Commands to betransmitted to Syncom from ground stations include telemetry andcommunications system switching, gas jet firing, and apogee motorfiring.

The command decoders consist of the circuitry required toprocess the ground commands. Electronics are turned on or off with 12


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-12-

Attitude and velocity control while in orbit is achievedthrough two hydrogen peroxide systems. Four pressurized sphericaltanks (two for each system) mounted opposite each other and connectedby manifolds contain the propellant for each system.

Each of the control systems has two Jets. One Jet firesparallel to the spin axis of the spacacraft and the other perpen-dicular to the spin axis.

The systems each contain five pounds of 90 per cent hydrogenperoxide pressurized ': o -OO pounds per square


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-13-

Final precise adjustments in the spacecraft's synchronismare achieved by pulsing a velocity contro'l Jet located on th3side of the spacecraft.

The Launch Vehicle

The TAD consists of a Delta vehicle with the first stagemodified by three Thiokol solid rocket motors of 53,850 poundsthrust each, which increases the liftoff thrust from a nominal172,000 pounds to a nominal 333,550 pounds.

The TAD will fly the higher-thrust X-258 third stage motor


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-14- ()The TAD rocket has the following general characteristics:Height: 90 feetMaximum diameter: Eight feetLiftoff weight: About 71 tons

First stage: Modified Air Force Thor, produced by Douglas Aircraft Co.Fuel: Liquid (kerosene with liquid

oxygen as oxidizer)Thrust: 300,000 pourndsBurning time: About two minutes and 25secondsDelta space weight: About 64 tons (with solid


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[ -1JTh) ?lirhtThe Thor vehicle fires belore liftoff, and the three solid

rockets, ignited by a flight source, almost immediately on liftoff.The solid motors burn for approximately 27 seconds, followed by a13-second liftoff period. At liftoff plus 70 seconds, the emptysolid casings are jettisoned.

Four seconds after liftoff, the Bell Telephone Laboratoriesguidance system begins a four-step program wherein the vehicle isrolled to a flight azimuth of 95 degrees from true north. Thisincludes a combined yaw, pitch and roll maneuver. The program lasts


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-16-Just before second stare apogee, the spin rockets which

spin-up the third stage are fired. Two seconds later, the secondstage gas retro system is activated and the second stage isseparated. Third stage is ignited four seconds after second stageseparation and burns for 22.6 seconds.

If all goes well Syncom will be injected into the transferorbit about 695 miles above the Gulf of Guinea off the west coastof Africa.

The third stage is Jettisoned 70 seconds after its ignitionand


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O- 1-7-Robc,,t J. Dircey is GE.I'C Project IManai or for Syncom; Don V.

Fordyce, '2ynorom roject Coordinator, and Forrest H. Wainscott isSpacecraft Manager. William R. Schindler is Delta Program Manager.Robert II. ray heads the Goddard Field Projects Branch at CapeKennedy.

Syncom was designed and built by the Hughes Aircraft Co.,Culver City, Calif. Hughes also operates telemetry and commandground stations, under the direction of GSFC, at Salisbury, Australia,on board the USNS Kingsport and at Lakehurst, N.J.

The Delta was built by the Douglas Aircraft Co., Santa Monica,


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-18-0Department of Defense Participation

Communications with Syncom C during th4 launch phase willbe provided by Department of Defense surface terminals underthe technical and operational direction of the U.S. Army SatelliteCommunications (SATCOM) Agency, which has its headquarters atFort Monmouth, N.J. From its Test Operations Center there it willconduct and evaluate the communications experimental test programfor NASA.

The SATCOM Agency is commanded by Brig. Gen. J. Wilson Johnston.


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-19-The QATCO01 Agency is Project Manager for the Army's portion

-- surface communications environment -- of the Defense CommunicationsSatellite Program. Because of the experience it had gained inprevious satellite communications projects, and because it hadsurface terminal facilities already developed and in being, theSATCOM Agency was assigned by Department of Defense in 1962 tosupport NASA in the Syncom project.

Since the launch of Syncom II on July 26, 1963, over 2,800hours of communication have been logged with the satellite,' including


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CO-AXIAL SLOTTED ARRAY ANTENNA

TRAVELING-WAVE TUBE

ANTENIA ELECTRONICS -.--.EQUADRANT NO.I ELECTRONICS

LATERAL HYDROGEN PEROXIDE JET

QUADRANT NO.3 ELECTRONICS

SOLAR CELLSAXIAL HYDROGEN PEROXIDE JET

ORIENTATION JET SOLAR SENSOR

APOGEE MOTORSOLAR SENSORNITROGEN VENT VALVE

PRESSURE RELIEF VALVE

OUADRANT NO.2 ELECTRONICS APOGEE MOTOR NOZZLE

SYNCOM C SPACECRAFTFIGURE C


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SYNCOM C ORBITING SEQUENCEso 320 ISO S IS0 120- 1 o 30 0 0 60 - 90O I I I I I - I| ,- I ~, ' I I I1 I( I"\ I I I I I I I I I I"v~.4A ,n S'X 8 >TAGE

BURNOJ13rD0 APOGEfI I 28 3D -t\ 9St GLEGIN SYNCHRONOUS ORBIT 3 LE T

3a' ~ ~ ~ A 17t' 2n APOGEE17 P l l3d T GE8 R OU H 30

-0 120A GO (P E R I O DT S+E 1 < -EORIEN1DEORIENT

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