COMSTAR I-A Press Kit

8/7/2019 COMSTAR I-A Press Kit

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National Aeronautics andSpace AdministrationWashington. D C 20546AC 202 755-8370

For Release IMMEDIATE

Press Kit Project COMSTAR I-ARELEASE NO: 76-75

ContentsGENERAL RELEASE .............................. 1-2ATLAS/CENTAUR LAUNCH VEHICLE ...................... 3-5TYPICAL LAUNCH SEQUENCE FOR COMSTAR I ......... 6LAUNCH OPERATIONS ...... .............. . . 7NASA.TEAM ...................................... 7-8


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National Aeronautics andSpace AdministrationWashington, D C 20546AC 202 755-8370

For ReleaseBill O'DonnellHeadquarters, Washington, D.C. IMMEDIATE(Phone: 202/755-8487)

RELEASE NO: 76-75

NASA TO LAUN4CH COMSTAR SATELLITE FOR COMSAT GENERAL

COMSTAR i-A, the first in a series of domestic communi-cations satellites of COMSAT General Corp., will be launchedby NASA May 6 at Cape Canaveral, Fla.

The Atlas/Centaur vehicle and associated support acti-vities will be provided by NASA which will be reimbursed byCOMSAT General, a subsidiary of Communications SatelliteCorp. (COMSAT).

The COMSTAR spacecraft will be leased by COMSAT to theAmerican Telephone and Telegraph Co. (AT&T) as part of anationwide communications network. Each COMSTAR will havea capacity for more than 14,000 two-way high quality voicecircuits.

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Three COMSTARs are planned for the system which willbe capable of providing communications to the 48 contiguousstates, Alaska, Hawaii and Puerto Rico.

The COMSTARs will be placed into geosynchronous orbitsat 36,000 kilometers (22,300 miles) altitude.

Launch wi.ndow May 6 opens at 6 p.m. and closes at7:12 p.m. EDT.

The launch of COMSTAR spacecraft aboard Atlas/Centaurrockets requires the coordinated efforts of a large govern-ment and industry team. NASA's Lewis Research Center,Cleveland, Ohio, has management responsibility for theAtlas/Centaur development and operation. NASA's John F.Kennedy Space Center, Fla., is assigned vehicle checkoutand launch responsibility once the vehicle reaches CapeCanaveral.

(END OF GENERAL RELEASE. BACKGROUND INFORMATION FOLLOWS.)


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ATLAS/CENTAUR LAUNCH VEHICLE

The Atlas/Centaur is NASA's standard launch vehicle forintermediate-weight payloads. It is used for the launch ofEarth-orbital, Earth-synchronous and interplanetary missions.

Centaur was the nation's first high-energy, liquid-hydrogen/liquid-oxygen propelled rocket. Developed andlaunched under the direction of NASA's Lewis Research Center,it became operational in 1966 with the launch of Surveyor 1,the first U.S. spacecraft to soft-land on the Moon's surface.

Since that time, both the Atlas booster and Centaursecond st'-rge have undergone many improvements. At present,the vehicle combination can place 4,530 kilograms (10,000pounds) in low Earth orbit, 1,880 kg (4,150 lb.) in a syn-chronous transfer orbit and 900 kg (2,000 lb.) on an inter-planetary trajectory.

The Atlas/Centaur, standing approximately 40.8 meters(134 feet) high, consists of an Atlas SLV-3D booster andCentaur D-lA second stage. The Atlas booster develops 1,920kilonewtons (43',300 lb.) of thrust at liftoff using two822,920-newton (185,000 lb.) thrust booster engines, one266,890-N (60,000 lb.) thrust sustainer engine and two ver-nier engines developing 2,890 N (650 lb.) thrust each. Thetwo RL-10 engines on Centaur produce a total of 133,450 N(30,000 lb.) thrust. Both the Atlas and the centaur are3.048 m (10 ft.) in diameter.

Until early 1974, Centaur was used exclusively in com-bination with the Atlas booster. Now it is also used witha Titan III booster to launch heavier paylodds into Earthorbit and interplanetary trajectories.The Atlas and the Centaur vehicles have been updatedover the years. Thrust of the Atlas engines has been in-

creased about 222,400 N (50,000 lb.) since its debut in thespace program in the early 1960s.The Centaur D-1A has an integrated electronic systemthat performs a major role in checking itself ancd other

vehicle systems Before launch and also maintains controlof major events after liftoff.

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The new Centaur system handles navigation and guidancetasks, controls pressurization and venting, propellant man-agement, telemetry formats and transmission and initiatesvehicle events. Most operational needs can be met bychanging the computer software.The Centaur D-lA also incorporates a redundant hydro-gen peroxide attitude control system that is tolerant of aperoxide "engine out" situation.

Typical Launch Vehicle Characteristics

Liftoff weight including spacecraft: 148,055 kg (326,400 lb.)Liftoff height: 40.8 m (134 ft.)Launch complex: 36-A

Atlas Booster Centaur StageWeight 130,469 kg 17,781 kg(with propellants) (287,630 lb.) (39,200 lb.)Height 21.3 m (70 ft.) 19.5 m (64 ft.with payloadfairing)Thrust 1,919 kn 133,447 N(431,300 lb.) (30,000 lb.)at sea level. in vacuum.Propellants Liquid oxygen Liquid oxygenand RP-1 and liquid

hydrogenPropulsion MA-5 system two Two 66,i23-N822,921-N (185,000 (15,000-lb.)

lb.) thrust booster thrust RL-10engines, one engines, 12266,893-N (60,000 small hydrogenlb.) thrust sus- peroxide thrusters.tainer engine, two2,891-N (650-lb.)thrust vernierengines.

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Atlas Booster Centaur StageVelocity 8,877 kmph (5,517 33,339 1kmph(Earth relative) mph) at booster (20,724 mph)

engine cutoff at spacecraft(BECO), 12,294 separation.kmph (8,076 mph)at sustainerengine cutoff(SECO).

Guidance Preprogrammed pro- Inertial guidance.file through BECO.Switch to inertialguidance for sus-tainer phase.

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LAUNCH OPERATIONS

NASA's John F. Kennedy Space Center and its Expendableehicles Directorate play key roles in the preparation andaunch of Atlas/Centaur-38 carrying the COMSTAR spacecraftinto orbit.The Atlas and Centaur stages were erected on Pad A ataunch Complex 36, Cape Canaveral Air Force Station in lateebruary. The spacecraft arrive- at KSC on March 29 andnderwent initial checkout in Hangar AO in the Cape Canaveralir Force Station Industrial Area. It was later moved topacecraft Assembly and Encapsulation Facility-2 in the KSCndustrial Area fo r additional checkout and encapsulation inhe payload shroud which will protect it during its flighthrough the atmosphere.The encapsulated spacecraft was mated with Atlas,/entaur-38 April 27. In providing launch operations, KSCandles scheduling of test milestones, participates in check-ut activities and review of data to assure that the spaceehicle has met all its test requirements and is ready foraunch.All launch vehicle and pad operations during the launchountdown are conducted from the blockhouse of Complex 36 byjoint government-industry team.

NASA TEAMNASA HeadquartersJohn F.. Yardley Associate Administratorfo r Space FlightJoseph B. Mahon Director of ExpendableLaunch Vehicle ProgramsF. R. Schmidt Manager. Atlas/Centaur

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Lewis Research CenterDr. Bruce T. Lundin DirectorDr. Seymour C. Himmel Associate Director forFlight ProgramsAndrew J. Stofan Director of Launch VehiclesHenry 0. Slone Centaur Systems ManagerKenneth A. Adams COMSTAR I Mission ProjectEngineerRichard A. Flage Launch Vehicle TestIntegration EngineerRichard E. Orzechowski Launch Vehicle RangeIntegration Engineer

Kennedy Space CenterLee R. Scherer DirectorMiles Ross Deputy DirectorDr. Walter J. Kapryan Director, Space VehiclesOperationsGeorge F. Page Director, Expendable VehiclesJohn D. Gossett Manager, Centaur OperationsCreighton A. Terhune Engineering Manager,Centaur OperationsJ. M. Harrington Complex 36 OperationsManagerJames N. McKnight Project Engineer, COMSTARSpacecraft

April 27, 1976


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National Aeronautics andSpace AdministrationWashington D C 20546AC 202 755-8370

For ReleaseMiguel PadillaHeadquarters, Washington, D.C. IMMEDIATE(Phone: 202/755-3147)

RELEASE NO: 76-76

NASA TESTING GASEOUS NUCLEAR CORE REACTOR

The Los Alamos Scientific Laboratory in New Mexico hasbegun testing a model of a nuclear reactor being developedunder a NASA-sponsored research program for applications inspace. The reactor would use a gaseous rather than a solidnuclear fuel.

A gaseous fuel reactor capable of producing power forEarth as well as for space applications could operate attemperatures at which solid fuel rods would melt. This higheroperating temperature would make the gaseous fuel reactorpotentially more efficient than conventional solid corereactors.

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The gaseous fuel permits continuous fuel reprocessing,eliminating the need for a separate nuclear fuel reproces-sing plant required for solid fuel. Predicted fueL effi-ciency in space power applications, would translate intoeconomy and reduced specific mass and weight.

Recent success in nuclear energized laser researchconducted under NASA direction indicates that part of thepower from a gaseous fuel reactor could be generated directlyas laser light beams, offering the prospect of a new genera-tion of space technology. Using this concept, energy froma nuclear power station in space might be transmitted by

laser beam over large distances to users on space platforms,lunar oases or to spaceships for propulsion.

Besides its predicted advantages for space application,a gaseous fuel reactor would have several advantages if usedon Earth. Loss-of-cooling and melt-down problems common tosolid fuel reactors might be largely eliminated. Gaseousreactors would be able to burn up a portion of their ownlong-lived nuclear waste products.

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The gaseous reactor experiments now in progress areusing hardware salvaged from an earlier NASA-Atomic EnergyCommission nuclear rocket program.

The next steps in the research program will be testsof the experimental reactor with recycling of the gaseousfuel and its mechanical confinement for high temperature

and high power operation.

The work at Los Alamos is supplemented by theoreticaland experimental research under NASA grants with five uni-versities and an industrial laboratory.

0 ArlfI97

April 23', 1976

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COMSTAR I-A Press Kit