ionosphere beacon explorer press kit

8/8/2019 Ionosphere Beacon Explorer Press Kit

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NEWS RELEASENATIONAL AERONAUTICS AND SPACE ADMINISTRATION400 MARYLAND AVENUE, SW , WASHINGTON, D. C. 20546TELEPHONES: WORTH 2-4155 -------- WORTH3-6925FOR RELEASE: SUNDAYMarch 15, 1964

RELEASE NO: 64-60

(NOTE TO EDITORS: On Aug. 4, 1963 NASAissued Release No. 63-157, 'NASA to LaunchPolar Ionosphere Beacon Satellite." That launch,scheduled for Aug. 15, 1963, was postponed andnow has been rescheduled. Because of a number ofchanges in the mission, this press kit should beused in place of NASA Release Nto. 63-157.)

NASA TO LAUNCH IONOSPHERE BEACON EXPLORIER


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information obtained by the stations will be exchangedthrough a Scientific Data Center operated by the GoddardSpace Flight Center Greenbelt, Md.

The satellite built by Johns Hopkins' Applied PhysicsLaboratory, also will carry an experiment to measure electrondensities and temperatures in its immediate vicinity. In-formation obtained from this experiment will be sent by codedtelemetry to ground stations of the NASA STADAN network.

In addition to making major ionosphere studies, theBeacon Explorer will serve as a test bed for tracking experi-ments related to the science oi, geodesy -- the study of thesize and shape of the Earth.

In one experiment, a LASER (Light Amplification bySimulated Emtssion of Radiation) device located near NASA's


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Secondly, the Beacon Explorer will transmit on twofrequencies which will permit precision tracking by ground 4stations. This tracking system, similar to that used onprevious U.S. Navy Transit satellites, will continue study ofthe Doppler method of satellite tracking and of the influenceof the ionosphere on Doppler tracking.

If these experiments are successful, a back-up BeaconExplorer is being considered for more extensive experimentsin geodesy -- involving both the LASER and Doppler method ofsatellite tracking.

Beacon Explorer is the last of five satellites in thefirst phase of the NASA ionosphere exploration program. Thesesatellites fall into three general types depending upon theirassigned tasks.

The first type, called direct measurement Explorers, is


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-5-The second type, called topside sounders, transmits

radio signals of varying wavelengths which are reflectedfrom the topside of the ionosphere with the echo being re-ceived back at the satellite. Topside sounder satellitesby such a radar-like technique permit the study of electronstructure as a function of altitude but only in the topsideof the ionosphere. NASA has two topside sounder satellites,the Canadian-built Alouette, launched Sept. 29, 1962, andthe Ionosphere Explorer, which is currently scheduled forlaunch at the Pacific Missile Range.

The Beacon Explorer represents the third type of ion-osphere satellite. Its radio transmissions are made at wave-lengths which penetrate through the ionosphere to the ground.Thus, it will transmit raw' cross-section data on the structureof both the top and bottomside (without altitude discrimination)of the ionosphere directly to ground stations. This worldwide


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It is the ionosphere, a region of electrically chargedgases, beginning about 35 miles above the Earth, which makespossible long-range radio communications. The ionospherechanges as rapidly as does the Earth's weather. A globalsurvey of this enormous electrified mirror will be as impor-tant to predicting communications frequency variations andblackouts as the TIROS weather satellite pictures of globalcloud cover have been in predicting the weather.

The Beacon Explorer satellite program is part of thescientific space exploration program of NASA's Office of SpaceScience and Applications. Project management of the satelliteis directed by the NASA Goddard Space Flight Center.

In addition to Goddard, the major participants in theprogram are the University of Illinois, Pennsylvania StateUniversity, Stanford University and the Central Radio Propaga-tion Laboratory of the National Bureau of Standards, an agency


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-7-The LASER experiment is in the program of NASA's

Office of Advanced Research and Technology, with projectdirection assigned to Goddard. The LASER device for usein the tracking experiment was built by Goddard. The glassreflectors were produced by the Corning Glass Works, Corning,N.Y., and assembled into an array by General Electric'sSpace Technology Center, Valley Forge, Pa.

The three-stage Delta launch rocket is fabricated by theDouglas Aircraft Co., Santa Monica, Calif. It will be reachingfor its 23rd consecutive successful satellite launching -- arecord for reliability unmatched in U.S. space history.

THE BEACON EXPLORER SATELLITE

The Beacon Explorer is an octagonal-shaped satellitewith four solar panels extending from its sides like the bladesof a windmill. It weighs about 120 pounds.


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IONOSPHERE BEACON SATELLITECUTAWAY VIEW

20 Mc, 40 Mc, 41 Mc CORNER REFLECTORANTENNA ASSEMBLY

MAGNETOMETER- | COMMAND 324 Mc, 360 McRECEIVER

# \TELEMETERUMBILICAL CONNECTOR PDMPOWER SWITCH COMMUTATORCOMMAND LOGIC

40/41 Mc TRANSMITTER PAM COMMUTATOR324/360 Mc TRANSMITTER162 Mc TRANSMITTERMAGNETOMETER

SOLAR CELLS 20 McTRANSMITTER136 ME, 162C DUAL OSCILLATOR

BATTERIES N


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The solar panels are covered with cells to convertenergy from the Sun into electricity to recharge nickel-cadmium batteries which provide the power to operate thesatellite. The panels are 10 inches wide and five and one-half feet long. Twice as many solar cells as are neededfor initial power have been fixed to the satellite blades.As the cells deteriorate because of radiation effects, re-serve banks of solar cells will be commanded into the opera-ting system to provide electrical energy.

Extending from the ends of opposite solar panels aretwo five-foot whip antennas and two dipole antennas for thebeacon transmitter.

Four signals will be transmitted at power levels over100mw to ensure good signal-to-noise ratios for ionosphericexperiments. Three lower frequency signals -- at 20, 40 and41 megacycles -- will be transmitted from the two dipole antennas


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which will provide information on satellite temperatureb,voltages, current and attitude to the NASA SatelliteTracking and Data Acquisition Network (STADAN).

During launch, the four solar blades are folded overthe third stage of the Delta rocket. They are held in placeby cables used for a "yo-yo" despin mechanism. An adaptermates the satellite to the Delta third stage and containsswitches that are timed to release the despin device about11 minutes after third stage burnout. About five minuteslater, the satellite will separate from the third stage.

The LASER reflectors are one-inch prisms mounted on aneight-sided pyramid on the satellite. These reflectors --mounted in such a manner that they will reflect the LASERlight from almost any angle -- are cubes of fused silica, anextremely pure type of glass. There are 360 reflectors on thesatellite. Two bar magnets,


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An unusual automatic temperature control system hasbeen built into the satellite. Vacuum insulation betweeninstruments and the shell of the satellite shields the in-terior from the great variations of temperature on the out-side. Uhen the internal temperature of the spacecraft dropsbelow the desired 70 degrees F., eight Mercury thermostatstrigger an onboard power system fed by a special bank ofsolar cells which supply the power necessary to maintainthe desired internal temperature. Such uniform internaltemperature is expected to improve reliability and increasethe operating lifetime of the satellite components.

THE IONOSPHERE EXPERIMENT AND HOW IT WORKS

The overall scientific objectives of the Beacon Explorercan be summarized briefly as follows:

-Study the behavior and electron population of


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-11--Determine the geometry and distribution of ir.regularities in the ionosphere.

Most of the satellite's investigations will be con-cerned with a search for variations in the structure ofthe ionosphere. It will do this by measuring the totalnumber of electrons between itself and the ground.

Measurements of electron distribution along the lineof sight between the satellite and a ground station will bema4e in two ways. Thepe are the Doppler Shift and FaradayRotation methods. Both depend upon the influences that theionosphere exerts upon the signal sent out by the satellite'sradio beacons.

The Doppler Shift Method. One of the characteristics ofa signal received from a satellite moving in orbit is that itsradio signals are subject to a phenomenon called the Doppler


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The Faraday Rotation Method. This is a rotation of theplane of polarization of the radio waves that is produced bythe waves passing through the ionosphere. However, if wavesare sent through a layer of charged particles, such as theionosphere, then the plane of polarization is graduallytwisted along a helical path. It is like taking a long,slender curtain and twisting it Into a corkscrew shape. Thistwisting is called the Faraday rotation, and is the result ofinteractions between the radio waves and the geomagnetic fieldsurrounding electrons in the ionosphere. If the number of timesthe plane of polarization has been rotated between satellite andEarth can be determined, the electron content can be calculated.This is most easily accomplished by measuring the rotation atseveral frequencies.

By using a straight dipole antenna on the ground, a maximumstrength signal will be received when the polarization or the


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Thus, with simple radio receivers and antennas, a greatdeal of data can be acquired on the ground.

The extent to which variations in the electron content ofthe ionosphere can be measured then is limited only by thenumber and 'location., of ground stations. And, each stationwill be able to make a real time measurement each time thesatellite passes within radio range.

THE LASER EXPERIMENT

The Beacon Explorer will carry a 10-pound array of fusedsilica glass rei1ectors designed to return back to Earth lightsignals aimed at it from a LASER.

Mounted on the satellite's body are 360 one-inch diameterglass prisms called cube-corner" reflectors. These are con-structed in such a way that light striking them from almost


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Goddard experimenters plan to attempt the first illumina-tion of the satellite reflectors during the early night-timepasses over Wallops Island. This may occur as early as 36hours after launch. A planned orbital altitude of 750 mileswill place the Beacon Explorer'at a typical slant range ofapproximately 1,000 miles and it will appear by reflected sun-light as a star of about the ninth magnitude -- 20 times fainterthan a star which can be seen by the naked eye.

The LASER system is mounted on an IGOR (InterceptGround Optical Recorder) telescope normally used by Wallopspersonnel to track sounding rockets. Operators will aim thetelescope along the predicted path of the Beacon Explorer andwhen they see it, they will "flash" the LASER light at a rateof one flash per second.

If all goes according to plan, the reflector array willbe illuminated and will return a small portion of the light


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In the event of overcast or inclement weather,illumination attempts will be delayed until opticalsightings are possible.

The measurements of time between initiation of thelight signal and reception at the photomultiplier willgive the precise distance of the satellite for each secondof time. These values will be recorded at the telescopesite and later sent to Goddard where they will be comparedwith distances calculated from other tracking instruments,such as NASA's Space Tracking and Data Acquisition Network(STADAN). These distance measurements are expected to bemore precise than those obtained through other tracking pro-cedures and may be used to define the Beacon Explorer satel-lite orbit more accurately.

Results of the experiment may lead to a more definitedetermination of the Earth's shape and development of improved


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As this red light is reflected back and forth insidethe rod, the bouncing rays hit other excited chromiumatoms and "stimulate" them to give off more red rays. Itis from this stimulated emission that the LASER (LightAmplification through the Stimulated Emission of Radiation)gets its name. These rays a-e in phase with each other andare parallel to each other as they bounce back and forthbetween the reflecting rod ends. Scientists term this"coherent" light, in contrast with random sources havingdiffuse-characteristics such as the Sun, electrical and neongas lamps.

Within a fraction of a millionth of a second this chainreaction builds to a powerful beam that "bursts" out one endof the rod which has been made more transparent than the other.The LASER light can be directed into a narrow pencil beam whichdoes not lose its effective strength before reaching the target.


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satellite launched into orbit by Delta. To date, the Deltarecord includes 22 successes. One failure occurred duringits first launch attempt. The Delta program is managed bythe Goddard Space Flight Center.

Delta has the following general characteristics:Height: 90 feetMaximum Diameter: 8 feetLift-off Weight: About 57 tonsFirst Stage: Modified Air Force Thor, produced byDouglas Aircraft Co.Fuel: Liquid (Kerosene with liquidoxygen as oxidizer)Thrust: 170,000 poundsBurning Time: About two minutes and 25 secondsWeight: Over 50 tonsSecond Stage: Aerojet General Corp., JA 10-118 propulsionsystemFuel: LiquidThrust: About 7,500 poundsBurning Time: About two minutes, 40 secondsWeight: Two and one-half tons

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During first and second stage powered flight, theBell Telephone Laboratory radio-guidance system is usedfor inflight trajectory corrections. It also commandssecond-stage cutoff when the desired position, velocityand altitude have been achieved.

Following second stage cutoff, an 11-minute coastperiod occurs. Near the end of this period, small rocketsmounted on a table between the second and third stages ig-nite and spin up the third stage and the satellite to 160 rpm.The second stage then separates and third stage ignition occurs,giving the satellite its final boost toward orbital injection.

Eleven minutes after burnout of the third stage, the"yo-yo'; despin mechanism will unwind and reduce the spin rateto 40 rpm and solar panel erection will take place. The inertiaof the panels coupled with the effect of the despin mechanismwill result in a further despin to about four rpm. Separation


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-19-THE BEACON EXPLORER TEAM

The following key officials are responsible for theBeacon Explorer satellite program:NASA Headquarters

Dr. Homer E. Newell, Associate Administrator forSpace Science and Applications

M. J. Aucremanne, Ionosphere Explorer Program OfficerT. Bland Norris, Delta Program ManagerDr. John M. Walker, Chief of Communications and TrackingBranch, Office of Advanced Research and TechnologyRoland H. Chase, LASER Project Scientist, OART

Goddard Space Flight CenterDr. Harry J. Goett, DirectorDr. John W. Townsend, Jr., Associate Director, Office of

Space Science and Satellite ApplicationsFrank T. Martin, Project ManagerRobert E. Bourdeau, Project Scientist


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-20-Applied Physics Laboratory, Johns Hopkins University

Donald R. Bianco, Project Engineer

Participating AgenciesUniversity of Illinoii3Pennsylvania State UniversityStanford UniversityCentral Radio Propagation Laboratory, U.S. Bureau ofStandards

BEACON EXPLORER GROUND STATIONSCountry Station Investigator & Address

Antarctica Wilkes Base Dr. G. H. MunroRadio Res. Board Lab.School of Electrical Engr.University of SydneySydney, NSWAustraliaArgentina Tucuman Sandro RadicellaEstacion Ionosferica


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-21-Country Station Investigator & AddressAustria Graz Prof. 0. BurkardInstitut fur Meteorologieund Geophysik derUniversitat GrazGrazAustriaAustralia Adelaide Dr. B. H. BriggsUniversity of AdelaideDepartment of PhysicsSouth Australia

Brisbane Prof. H. C. WebsterUniversity of QueenslandDepartment of PhysicsSaint Lucia, BrisbaneAustralia

Camden Dr. E. B. ArmstrongCommonwealth Scientific andIndustrial Res. OrganizationCamden, N.S.W.AustraliaHobart Dr. G. H. MunroMacquarie ItMelbourne "


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Country Station Investigator & AddressErazil Belem Dr. F. de Mendonca

Natal

Sao Jose dos CamposFederation of Jamaica Prof. R. W. H. WrightW. Indies University College of theWest IndiesMona, Kingston 7Jamaica, B. West IndiesCanada Baker Lake Prof. G. W. Swenson, Jr.

Electrical Engr. Research Lab.University of IllinoisUrbanaIllinoisSaskatoon Dr. A. KavadasInst. of Upper Atmos. PhysicsUniversity of SaskatchewanSaskatoon, SaskatchewanCanada

British Victoria Dr. G. McI. BoydColumbia Inst. of Earth ScienceUniversity of BritishColumbia


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-23-Country Station Investigator & Address

France Val-Joyeux Dr. J. Papet-Lepine(Cont.) Station Scientifique duVal-JoyeuxVillepreux (Seine et Oise)FranceGhana Radastra Rev. J. R. Koster (PhD)Department or PhysicsUniversity of GhanaLegon - AccraGhana

Kumasi Rev. J. R. KosterGermany, West Bochum H. KaminskiStadt BochumBochum-SundernBlankensteinerStrasse 200Germany

Breisach Dr. K. RawerIonospharen-Institut of theFernmeldetechnischesZentralamtBreisach/Rh.,Germany


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Greenland Thule Dr. Gary S. SalesLowell Technologice' Inst.Res. FoundationP. 0. Box 709Lowell, Mass.Hong Kong Hong Kong G. 0. WalkerPhysics DepartmentUniversity of Hong KongHong KongIndia Ahmedabad Dr. K. R. RamanathanPhysical Res. LaboratoryNavrangpura

Ahmedabad-9IndiaHyderabad Dr. E. B. RaoDefence Electronics Res.Laboratory, Research &Development Orgn.,Ministry of DefenceChandrayanagutta Lines

Hyderabad 5South IndiaNew Delhi Dr. Y. V. SomayajuluRadio Propagation UnitNational Physical Laboratory


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Country Statiorn Investigator & AddressItaly Firenze Prof. P. F. CheccacciCentro Microonde delConsiglioNazionale delle RicercheFirenzeItalyJapan Tokyo Dr. Yoshiaki NakataRadio Research Labs.Ministry of Posts andTelecommunicationsKokubunji P. 0. TokyoJapanKenya Nairobi Prof. A. N. HunterRoyal College, NairobiP. 0. Box 30197NairobiKenyaMalaysia Singapore F. KiftRadio Research StationUniversity of SingaporeSingapore, 10MalaysiaNew Zealand Auckland Dr. J. E. TitheridgePhysics Department


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Country Station Investigator & Address

Norway KJeller J. FrihagenDivision for TelecommunicationNorwegian Defence ResearchEstablishmentKjeller pr LillestromNorway

Tromso J. FrihagenPeru Huancayo Dr. W. J. RossIonosphere Res. LaboratoryPennsylvania State Univ.

University Park, Pa.S. Africa Johannesburg Mr. L. Blumle(Union) Goddard Space Flight CenterNASAGreenbelt, Md.Spain Tortosa Dr. E. Ga.donObservatorio del EbroApartado 9TortosaSpainSudan Khartoum Dr. P. A. O'BrienPhysics DepartmentUniversity of


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-27-Country Station Investigator & AddressThailand Bangkok Dr. C. W. BergmanC.D. & T.C.c/o Seato Engineering SchoolSanam MahBangkokThailandUnited Aberystwyth, Cards Dr. W. J. G. BeynonKingdomn Department of PhysicsUniversity College of WalesAberystwythWalesEngland

Jodrell Bank Dr. G. N. TaylorUniversity of ManchesterNuffield Radio AstronomyLaboratoriesJodrell Bank, CheshireUnited Kingdom

S. Farnborough, Dr B. BurgessHants Radio DepartmentRoyal Aircraft EstablishmentSouth Farnborough, HantsEnglandSidmouth Dr. K. W. WeekesDepartment of Physics


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USA Adak, Alaska Prof. G. W. Swenson, Jr.(Cont.) Electrical Engr. Research Lab.University of IllinoisUrbana, IllinoisBlossom Point, Md. L. BlumleNASA Goddard Space FlightCenterGreenbelt, Md.Boulder, Colo. Dr. Robert S. LawrenceBoulder LaboratoriesNational Bureau of StandardsBoulder, Colo.College Alaska Mr. L. R. HughesPhase Perturbation ProjectSmyth Research Associates

3555 Aero CourtSan Diego, Calif.Deal, New Jersey Dr. P. R. ArendtUSA Elec. Research & Develop-ment LaboratoryInstitute for ExploratoryResearchFort Monmouth, N.J.Durham, New Professor R. E. Houston, Jr.Hampshire College of TechnologyDepartment of PhysicsUniversity of New Hampshire


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USA Hamilton, Mass. J. P. Mullen(Cont.) Radio Astronomy Branch 4CRZAIAir Force Cambridge Res.LaboratoriesBedford- Mass.Hanover Field, Professor M. G. MorganNew Hampshire Thayer School of Engr.

Dartmouth CollegeHanover, N.H.Houghton. Mich. Professor G. W. Swenson, Jr.Huntsville, Ala. Dr. E. MechtlyGeorge C. Marshall SpaceFlight CenterHuntsville, Ala.Palo Alto, Calif. Dr. 0. K. GarriottPoint Buchon, L. R. HughesCalif.Seattle, Wash. L. R. HughesTexas A&M Dr. John P. GermanDept. of Electrical Engr.Agricultural & MechanicalCollege of TexasCollege Station, Tex.


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USA Univ. Park, Pa. Dr. W. J. Ross(Cont.) Ionosphere Research Lab.Pennsylvania State Univ.University Park, Pa.Weston, Mass. Dr. Gary S. SalesLowell Technological Inst.Res. Foundation

P. 0. Box 709Lowell, Mass.Williamsburg Va. Dr. James D. Lawrence, Jr.College of William and MaryWilliamsburg, Va.

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ionosphere beacon explorer press kit

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