PE S NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Washington, D. C. 20546 202-755-8370 PROJECT: FOR RELEASE: On Receipt INTELSAT IV REXLEASE NO; \ 74-305 contents GENERAL RELEASE ............................... 1-3 ATLAS-CENTAUR LAUNCH VEHICLE .................. 4 INTELSAT LAUNCH WINDOWS ............... ........ 5 ATLAS-CENT/ UR FLIGHT HISTORY .................. 6 TYPICAL LAUNCH VEHICLE CHARISTICS ............. 7 TYPICAL LAUNCH SEQUENCE FOR INTELSAT IV ....... 8 INTELSAT TEAM ................................. 9 (NASft) 10 p https://ntrs.nasa.gov/search.jsp?R=19750002059 2020-03-23T03:33:41+00:00Z Ann Weeks Headquarters, Washington, B.C. (Phone: 202/755-8370) NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Washington, D. C 20546 (Phone: 202/755-8370) FOR RELEASE: On Receipt Hugh Harris Lewis Research Center, Cleveland, Ohio (Phone: 216/433-6415 or 6438) RELEASE NO: 74-305 SPACE AGENCY TO LAUNCH SIXTH IN COMMUNICATIONS SATELLITE SERIES The sixth in a series of INTELSAT IV commercial communication satellites will be launched by NASA for the Communications Satellite Corporation (COMSAT) aboard an Atlas-Centaur rocket from the John F. Kennedy Space Center, Fla. about Nov. 21. The launch window is 6:44 p.m. to 7:16 p.m. and 7:48 p.m. to 8:16 p.m. EST. The 1,406 kilogram (3,100 pound) satellite will be positioned on the equator over the Pacific Ocean. This second INTELSAT IV to be emplaced over the Pacific is needed to take care of the rapidly increasing international telephone, tele- vision and data transmissions over the Pacific. -more- November 14, 1974 -2- The Atlas-Centaur (AC-32), which was developed and is launched under the direction of NASA's Lewis Research Center, Cleveland, Ohio, will be place the satellite in a highly ellip- tical orbit ranging from approximately 537 to 35,880 kilometers (334 to 22,300 miles). After checkout and orientation of the spacecraft, a solid propellant rocket motor aboard the space- craft will be fired by COMSAT to circularize the orbit and position the satellite at synchronous altitude of 35,880 km (22,300 mi.). At that altitude, the speed of the spacecraft in orbit matches the rotational speed of the Earth so the satellite appears to hover over one spot. The new satellite, like others in the global commercial communication system, is owned by the International Tele- communications Satellite Consortium, called INTELSAT. COMSAT, the United States member, acts as manager on behalf of the other 86 nations in the organization. NASA is reimbursed for all costs of the launch and associated services by COMSAT on behalf of INTELSAT, under provisions of the Communications Satellite Act of 1962. -more- -3- The INTELSAT IV F-8 spacecraft is 2.38 meters (93.7 inches) in diameter and 5.28 m (208 in.) high over all, 2.82 m (111 in.) being the height of the solar panel. After the onboard apogee motor has been fired, the satellite will weigh 700 kg (1,544 Ibs.). The INTELSAT was originally scheduled for launch on July 18 of this year but was postponed when failure of integrated cir- cuits for flight computers was discovered during acceptance testing. The vibration testing caused a failure of the attach- ment of the semi-conductor chips to the substrate. Epoxy bond- ing of integrated circuits was put into production and passed all qualification acceptance testing. The same system will be used on all future Centaur vehicles. (END OF GENERAL RELEASE. BACKGROUND INFORMATION FOLLOWS). -4- ATLAS-CENTAUR LAUNCH VEHICLE The Atlas-Centaur is NASA's standard launch vehicle for intermediate weight payloads. It is used for the launch of Earth orbital, Earth synchronous and interplanetary missions. More Atlas-Centaur launches now are used and paid for by other government agencies and by private corporations than by NASA. Centaur was the nation's first high energy, liquid-hydrogen/ liquid-oxygen propelled rocket. Developed and launched under the direction of NASA's Lewis Research Center, Cleveland, Ohio, it became operational in 1966 with the launch of Surveyor I, the first U.S. spacecraft to soft land on the Moon's surface. The Atlas-Centaur, standing approximately .39.9 m (131 ft.) high, consists of an Atlas SLV-3D booster and Centaur D-1A second stage. The Atlas booster develops 1,918 kilonewtons (431,300 Ib.) of thrust at liftoff using two 822,880-newtons (185,000-lb.) thrust booster engines, one 266,880 N (60,000 Ib.) thrust sus- tainer engine and two vernier engines developing 2,891 N (650 Ib.) thrust each. The two RL-10 engines on Centaur produce a total of 131,000 N (30,000 Ib.) thrust. Both the Atlas and Centaur are 3.048 m (10 ft.) in diameter. Up to early 1974, Centaur was used exclusively in combina- tion with the Atlas booster. Now it is also used with a Titan III booster to launch heavier payloads into Earth orbit and onto interplanetary trajectories. The Centaur D-1A has an integrated electronic system which performs a major role in checking itself and other vehicle sys- tems before launch and also maintains control of major events after liftoff. The new Centaur system handles navigation, guidance tasks, controls pressurization, propellant management, telemetry formats and transmission and initiates vehicle events. Most operational needs can be met by changing the computer software. -more- -5- INTELSAT LAUNCH WINDOWS The primary factor determining the launch window for INTELSAT spacecraft is the angle of the Sun. It is desirable for the solar cells on the spacecraft to receive the maximum possible exposure during the transfer orbit. The Sun angle is at its best twice a day at noon and midnight GMT or 7 a.m. and 7 p.m. EST. Because of the greater convenience for launch crews and tracking operations, the 7 p.m. period is generally chosen. The launch window for AC-32 is 6:44 p.m. - 7:16 p.m., and 7:48 - 8:16 p.m. on Nov. 21, 22 (split window). The window is divided into two segments to avoid Sun interference with spacecraft Earth sensors. -more- -6- PO H 2 W NJ Hi- M W H 2 M M fCn '2 M to cn OJ 1 cn G O » CO otj w H O Z tr> 0 C in W cn K I K M I tflK K) I W CO\ n M 2! a i-3 K M CO i-3 O UJ ro I vo vo CTv oo vo (TV CO VO a\ vo U) I K M vo ^j u> vo -j UJ vo o\ VO VO ~J to vo n tr \^ O U W vo ^ rH in 0 en vo CM T CN rH CN O CO rH rH en o 00 rH en CM g O •H •P n)}»i <0(X 0) CO M 3(0 •Pg CU U CO in vo in en CO CO CM CO vo CM in i-H en CM rH- -. ,' *y CM O CO vo 00 in CM _ rH *-• fj H Hg . j_ij3 m 4-> c u rH rH VD rH O O i-H in VD en 00 CM en rH rH CO rH CN in rH 00 VO O CM G O CO •rl •P •P 0> •o U> £J •H rl •rl a n_l CU(0 o rH CO in rH rH VO 00 CN CM r^ o CN «. rH VO CO 00 CN CN CO vo •• i-H in rH CM VO .^ i-H X.X O O g rl O rH •P ^3 -^1id *o •P C! CO W -9- INTELSAT TEAM COMSAT Dr. Joseph V. Charyk George.P. Sampson Martin J. Votaw President Senior Vice President, Communication System Mgt. Assistant Vice President, Engineering Lewis Research Center Bruce T. Lundin Dr. Seymour C. Himmel Andrew- J. Stofan Henry O. Stone Vernon J. Weyers Director Associate Director for Flight Programs Director of Launch Vehicles Atlas-Centaur Project Manager INTELSAT Project Engineer Industry Team Prime Contractors Hughes Aircraft Company Sunnyvale, Calif. General Dynamics/Convair San Diego, Calif. Honeywell, Aerospace Division St. Petersburg, Fla. Pratt & Whitney West Palm Beach, Fla. Teledyne Northridge, Calif. Responsibility INTELSAT IV spacecraft Atlas-Centaur launch vehicle Centaur guidance inertial measurement group Centaur RL-10 engines Digital computer unit/PCM telemetry -end-

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