OGO-D Press Kit

8/8/2019 OGO-D Press Kit

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NATIONAL ACRONAUTI(S AN D SPACE ADMINISTRATION TELS WO 7-'11WASHINGTON, DC 2o546 W(o s-'?FOR RELEASEI FRIDAY P.M.

A July 21, 1967RELEASE NO: 67-187

PROJECT: OGO-D(To be launched no earlierthan July 26, 1967)

CONTENTS


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, NATIONAL AERONAUTICS AND SPACE ADMINISTRATION arc WO 2-4155NEWS WASHINGTON,D.C. 20546 WO 3-6925FOR RELEASE: FRIDAY P.M.July 21, 1967

RELEASE NO: 67-187

POLAR ORBITINGGEOPHYSICAL

LAB LAUNCH SET

The fourth Orbiting Geophysical Observatory (OGO-D) willbe launched into a nearly polar orbit by the National Aero-


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-2-4The 20 experiments carried in the 1,240-pound, insect-

shaped satellite will also obtain global data over a completerange of latitudes extending from the equator to the poles.

A Thrust-Augmented Thor Agena D launch vehicle willinject OGU-D into an orbit ranging from 259 statute miles(perigee) to 575 statute miles (apogee). The planned orbitalperiod will be 98.2 minutes and the inclination angle to theequator Is 86 degrees.


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-3-Because a detailed scientific picture of the Earth's

environment continually changes, the data from several OGOsatellites will help scientists to distinguish changes due totime, from changes due to position.

As an example, during a two-week period in November of1966, the three satellites were operated simultaneously anddata were obtained l'om 46 experiments at the same time.


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Data from 000 satellites has provided new knowledgeconcerning: the magnetispheric boundary, the transition region,the bow shock, the magnetospheric tall, the auroral regions,and the upper atmosphere.

These data are pointing the way to the resolution ofimportant questions in energetic particle and wave propagationphysics, ionic plasma physics, and photochemistry.


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-5-In the magnetospheric tail, rapid changes in the intensity

and flux of energetic particles have been observed followingmagnetic storms. Sudden collapse of a portion of the magneticfield in the tail and distortions of the day-side magnetosphereboundary have been correlated with ground-observed polar capmagnetic changes which generally precede auroral activity, andhave provided the first evidence of a common mechanism formajor changes in the magnetosphere and in the polar region.


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-.6-Other results relate to the clear identification of

the controlling influence of the geomagnetic field on ionpopulation. These findings which correlate well with electrondata derived from very low frequency noise, or whistlers,observed on the ground and data from other 000 experimentsindicate the existence of a new region, the plasmapause,w!--re there is a sudden decrease in electron and ion concentra-tion. These results have a very significant bearing on our


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The observatory, with booms and solar panels fully extended,is 49 feet long, about 20 feet wide and contains more than100,000 separate parts. During the launch phase, these append-ages are folded against the main body like a closed jackknife.

To obtain data from 25 per cent of the OGO-D experiments,or- side of the spacecraft must point toward Earth. Thus, thesabellite utilizes an attitude control system which keeps OGO-Dstabilized in all three axes (pitch, yaw and roll). The com-


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OGO prime contractor is TRW Systems, Redondo Beach,Calif. Douglas Aircraft, Santa Monica, Calif., developedthe Thor and Lockheed Missile and Space Corp., Sunnyvale,Calif., the Agena stage. Hundreds of subcontractors and vendorsacross the nation have provided various subsystems and elec-tronics for the satellite.(END OF GENERAL RELEASE; BAMKGROUND INFORMATION FOLLOWS)

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-9-OGO-D FACT SHEET

SPACECRAFT:Shape . . . . . . . . . .Main bedy is rectangular shape,six feet long, three feet wide,three feet high; with appendagesdeployed, spacecraft lookslike giant insect, is 49 feetlong and 20 feet wide.Overall Weight . . . . . 1,240 poundsExperiment Weight . . . .274 poundsAppendages . . . . . . . Two 22-foot booms; four four-foot booms; two solar panels,


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Time... . . .*... . . . 10:20 a.m., EDTWindow . . . . . . . . . . . .About one hour

NOMINAL ORBITAL ELENENTS:Apogee . . . . . . . . . . . .575 statute milesPerigee . . . . . . .. .. 259 statute milesPeriod . . . . . . . . . . . .98.1 minutesInclination . . . . . . . . . 86 degreesVelocity (at Agena burnout) . 17,398 miles per hour

TRACKING AND DATA ACQUISITION STATIONSNASA's Space Tracking and Data Acquisition Network


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OGO-D OBSERVATORY

ATTITUDE - CONTROL BOOMSOLAR - PANEL ASSEMBLY

EXPERIMENT CONTAINERS SOEP

,AFT EN D PANEL ASSEMBLY

- >UHF OMNIDIRECTIONAL ANTENNADRIVE ASSEMBLY

EXPERIMENT BOOMS, ~BOOM HINGE

VHF OMNIDIRECTIONAL ANTENNA

FULLY DEPLOYED IN ORBIT


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APPENDAGE EXPERIMENTATTITUDE CONTROL NOZZLES

RADIATING PANELS FORWARD END PANEL

UPPER DOOR ASSEMBLY


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-11-OGO-D SPACECRAFT

OGO-D consists of a main body about six feet long, three |feet deep and three feet wide. Attached to this section are12 appendages.

Two 22-foot-long booms, longest on the satellite, carryexperiment instrumentation which must be mounted away fromthe main body to avoid magnetic and other disturbing effects.Four four-foot-long booms carry somewhat less sensitive

experiments. 000 antennas are mounted away from the mainbody to take advantage or improved antenna patterns madepossible by this technique.Other external characteristics of the satellite includetwo box-like packages which carry experiments and can berotated about an axis normal to the long axis of thesatellite.


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An average of 50 watts and a peak of 80 watts of powerare reserved for experiments.Attitude Control System

The OGO-D attitude control system is designed to keepthe satellite stabilized in all three axes (pitch, yaw androll), within two degrees of local vertical, five degreesof the Sun, and one side oriented toward Earth. TheOPEPs are then oriented within five degrees of the orbitalplane. The stabilization provides a platform for accuratedirectional measurements.

Basically, the control system consists of horizonscanners, servos, gas Jets, electrically-driven flywheelsand associated electronics.Infrared horizon scanners control the bottom section of


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The temperatures of all assemblies within the main bodyare kept between about 41 to 95 degrees F. by sets of radiatingpanels and 112 temperature-actuated aluminum louvers locatedon three sides of the main body.The temperatures of appendage packages containingexperiment instruments are controlled by a similar thermalbalance technique, except that louvers are not used. Heatersare used to maintain temperature limits when experiments

are turned off.This system is designed to keep the temperatureswithin the appendage containers within the range of about32 to 104 degrees F.

Communications and Data Handling


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Data ProcessingData received on magnetic tape by the world-widenetwork of tracking and data acquisition stations (STADAN)will be forwarded to the 000 Control Center at the GoddardSpace Flight Center.Tracking data sent to Goddard will be used forcomputation of an accurate orbit for experimenters in dataanalysis and for spacecraft operations.Taped data will be processed by high-speed computers.When the processing is completed, digital computer tapeswill be produced for each experimenter.These tapes will contain data from each individual experi-ment, necessary timing information, as well as data onspacecraft temperatures, voltages,


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OGO-D SCIENTIFIC OBJECTIVES AND EXPERIMENTSThe 274 pounds packed in the 20 experiments of the OG0-Dspacecraft cover the broad spectrum of the space science dis-ciplines, and are correlative investigations in solar, aeronomy,energetic particle, auroral and airglow physics.The information collected by these various experimentsshould help in understanding the Earth's environment and thetime-dependent relationship that exists in galactic, inter-

planetary and planetary events, with emphasis on solar-terrestrial interactions.At the present time in space exploration, scientists knowhow to make many of the individual measurements of the magneticfield, particle flow, ionization, etc.The important question facing space scientists concerns the


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'.. New knowledge on the latitude and time-dependentvariations of the pressure, temperature, density and chemistryof the neutral atmosphere surrounding the Earth;

2. The relationship between solar X-ray and ultravioletemissions and their effect on the Earth's ionosphere, atmos-phere and airglow;3. Further inbight into the precipitation of energetic

particles and the influx of solar cosmic rays into the auroraland polar regions and the occurence of aurora;4. Measurement of solar ultraviolet and X-ray emissionsduring a period of moderate to high activity;5. More information concerning low energy particlestrapped in the Earth's magnetic field; the intensity of the


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ORBITING GEOPHYSICAL OBSERVATORYCORRELATIVE ASPECTS OF EARTH-SUN RELATIONSHIP

* IONIZATION* SUDDEN IONOSPHERIC ADISTURBANCES //@GALACTIC COSMIC* VERY LOW FREQUENCY / RADIATIONNOISE S SOLAR WIND SUN\ AIRGLOW SUN

* SOLAR FLARES*ELECTROMAGNETICRADIATION~

0 INTERPLANETARYMAGNETIC FIELDS

*T o MAGNETOSPHERIC COMPRESSION* HYDROMAGNETIC WAVESS PARTICLE ACCELERATION0 GEOMAGNETIC TRAPPINGLO PARTICLE BUNCHING

* RADIATION BELT DUMPING* POLAR CAP ABSORPTION* AURORA


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OGO-D SUMMARY OF EXPERIMENTSExperimenter Affiliation ExperimentDr. F.T. Haddock University of Michigan, Radio Astronomy (2.5 mc)Ann ArborDr. R. A. Helliwell Stanford University, VLF Noise and PropagationPalo Alto, Calif. (0.03 - 100 kc)Prof. M. G. Morgan Dartmouth College, Whistlers and AF Electromag-Hanover, N. H. netic Waves (0.5 - 20 kc)Dr. E. J. Smith JPL Low Frequency Magnetic FieldFluctuationsDr. R. E. Holzer University of California Low Frequency Magnetic FieldLos Angeles FluctuationsDr. J. C. Cain GSFC Magnetic Field Survey ODr. H. R. Anderson Rice University, Cosmic Ray and Polar RegionHouston, Texas Ionization StudyH. V. Neher Califor i Institute of Cosmic Ray and Polar RegionTechnology, Pasadena, Calif. Ionization StudyDr. J. A. Simpson Univ. of Chicago Energetic Particles SurveyDr. W. R. Webber Univ. of Minnesota, Galactic and Solar Cosmic RaysMinneapolisDr. J. A. Van Allen Univ. of Iowa, Iowa City Trapped and Precipating ParticlesDr. R. A. Hoffman. G3FC Low Energy Auroral Particles


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OGO-D SUMMARY OF EXPERIMENTS, CONTID.Experimenter Affiliation ExperimentProf. J. Blamont Univ. of Paris, Paris, France Airglow and AuroraEdith I. Reed GSFC Airglow and AuroraDr. P. W. Mange U. S. Naval Research Lab- Lyman Alpha and UV Airgloworatory, Washington, D.C.Dr. C. A. Barth Univ. of Colorado, Boulder UV Spectra of the Earth'sAtmosphereDr. L. A. Wallace Kitt Peak National Observa- UV Spectra of the Earthtstory, Tucson, Ariz. AtmosphereProf. L. Jones Univ. of Michigan, Ann Arbor Neutral Particle and IonMeasurementsH. A. Taylor GSFC Positive Ion Composition(1 - 45 AMU)G. P. Newton GSFC Neutral Particle MeasurementsDr. C. S. Nilsson Smithsonian Astrophysical I-1croumeteoritesObservatory, Cambridge, Mass.J. L. Donley GSFC Ionospheric Composition and

UV FluxDr. H. E. Hinteregger Air Force Cambridge Research Solar UV EmissionsLaboratories, Bedford, Mass.R. W. Kreplin U. S. Naval Research Laboratory Solar X-ray EmissionsWashington, D. C.

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CAINEXP. No. 6

3

VAN ALLENEXP. No . 10MANGECAIN EXP. No. 13* EXP. No. 6

KREPLIN SEDOEXP. No. 21 EXP. No . 20 SIMPSONEXP. No. 8BARTH WEBBER* EXP. No . 14 \EXP. No. 9

: X SMITH


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ATMOSPHERIC AND IONOSPHERIC MEASUREMENTSNeutral Particle Study - Goddard Space Flight Center

This experiment utilizes a Bayard-Alpert ionization gaugeto directly measure neutral particle temperatures and densitiesto observe variances with longitude, latitude, altitude, day-night and seasonal changes. The data obtained will extend theknowledge of both the structure of the atmosphere and its thermalequilibrium.

The gauge resembles a conventional triode except the gridis positive and the anode is a small central rod. Electronsemitted from one of three redundant filaments ionize the neu-tral particles by collision. The electrons are then attractedto the grid, which repels the positive ions


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Positive Ion Composition - Goddard Space Flight CenterThis experiment will obtain high resolution measurements(+ 1 AMU) of positive ion composition (1 to 45 AMU) within theEarth's lower ionosphere and the unexplored polar regions. Thesedata will help identify and study suspected transition regionsin the ionosphere where the predominent constituents may change.Results of a similar experiment on previous 000's have re-vealed a strong influence of the Earth's magnetic field uponthe distribution of ions.The instrument used is a Bennett r-f mass spectrometerlocated in the OPEP. The spectrometer consists of a tube witha number of plane-parallel knitted grids mounted at right anglesto the axis of the tube. A-C and D-C fields accelerate the Ionsdown the length of the tube toward a collector. To reach thecollector, the ions must pass through a retarding potential.


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Micrometeorites - Smithsonian Astrophysical ObservatoryThis experiment is one of a series of similar o0o experi-ments designed to provide a basic measure and understanding ofthe dust particle environment of the Earth. The experiment onOGO-D is designed specifically to measure the spatial density,vel city, and mass of dust particles in the mass range lo-13 to10Y grame. These measurements will be used to determine theorbits of these particles and to detect the existence of dustparticle streams. Investigations of the importance of geomag-netic control on the dynamics of the dust particles and correla-tion of the various measurements with geophysical, geomagneticand solar phenomena will also be attempted.The particles are detected by four tubular detectorsmounted on a short boom and aligned along the body axes of theobservatory. An incoming particle first penetrates a thin film


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Low Energy Auroral Particles --Goddard Space Flight CenterLow energy auroral particles will be studied through highresolution measurments of the energy spectra and pitch angledistribution of electrons and protons (0.5 to 20 kev). Know-ledge of low energy electrons and protons will contribute tounderstanding auroral and subauroral zone phenomena. Eightchannel electron multipliers with cylindrical curved plateelectrostatic analyzers are positioned on a short boom to lo-cate four detectors (center energy: 0.55 Nevy 1.0 Kev, 4.3 Kev,10.5 Kev) radially away from Earth and three detectors (centerenergy: 3.2 Kev) at angles of 300, 600, and 900. The eighthdetector will obtain background counts due to energetic par-ticles and x-rays. By-ground command, the polarity of the vol-tage on the analyzer plates is reversed allowing measurement ofeither electrons or protons.


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Lyman-.Alha and Ultraviolet Alrglow Study - U.S. Naval ResearchLaboratoryThis experiment will measure the flux of scattered hydrogenLyman-Alpha radiation (1216A0) incident upon the Earth and theEarth albedo (ratio of reflected to incident radiation) at 12160,1230-1350AO, and 1350-155CA0. Measuring the excitation of ultra-violet fluorescence produced by particles provides an effectivemeans of measuring the rate at which particles deliver energyto the atmosphere. A knowledge of the rate of energy input intothe upper atmosphere as a function of time and location willgreatly aid the understanding of both high altitude airglowemissions and of the origin of the electron component of theVan Allen belts. The Lyman-alpha measurement of atmosphericemissions can be related to spatial asymmetries in the atomichydrogen content near the dissociation level, and will provideinformation concerning variations in the vertical transport ofwater vapor and methane.


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SOLAR RAIATION EXPERIMWNTSSolar X-Ray Study - U.S. Naval Research Laboratory

Measuring the solar x-ray energy input to the Earth andits variations in order to understand the geophysical para-meters of the upper atmosphere is the objective of this ex-periment. Changes in the asolar radiation are one of the pri-mary environmental influences affecting the ionosphere. inparticular, solar x-ray bursts accompanying flares and activeprominences are the direct cause -of increased D region ioniza-tion, which in turn is responsible fo r radio fadeout, suddencosmic noise absorption (SCNA), and other manifestations of thesudden ionospheric disturbance (SID) event. By establishing aset of G-ray indices of solar activity, correlation with othergeophysical phenomena can be made. A study of time variationsin solar events and perhaps a more quantitative method ofclassifying solar events can be made by use of these indices.(Size classification of flares provides a poor measure of the


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The dispersed radiations from the gratings are separatedby a six-channel collimating slit system which is drivenmechanically in 512 discrete steps through a 12-degree rotation.For each collimator position, only radiation of the wavelengthsdetermined by the diffraction angle will be transmitted by thecollimator to six photocathodes in two photomultiplier tubes.The output pulses from the photomultiplier tubes are relatedto the input solar flux at the appropriate wavelength. The scan-ning may be commanded to execute only 37 steps instead of the512 about one of 32 selectable positions (wavelengths) for in-creased observation of temporal variations of intensities.

RADIO EMISSION MEASUREMENTSVLF Noise and Propagations - Stanford University

The objecbives of this experiment are to study VLF propa-gation, properties of the ionosphere, the origin of VLF iono-


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To meet these objectives, most of the data from the ob-servatory will be subjected to a detailed comparison with ob-servations made simultaneously at a network of ground-basedwhistler stations.

A simple broadband (500 cps to 18 kc) receiver with ad-Justable gain is used. In orbit, a 10-foot dipole antenna willbe deployed from a short boom.Radio Astronomy - University of Michigan

The prime objective of this experiment is to map thebrightness distribution of 2.5 Me cosmic radio noise.Other objectives are to observe certain ionospheric pheno-mena, one of which is a form of presumably locally generatednoise in the topside ionosphere. Although the origin of thisnoise is not yet clear, it is possibly caused by Cerenkov


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The magnetometer is composed of a triaxial array of searchcoils situated at the end of one of the long booms for isola-tion from magnetic noise generated by the spacecraft and otherexperiments. This type of magnetometer is insensitive to fixed(d-c) magnetic fields, since a search coil basically consistsof many thousands of turns of copper wire wound on a high mucore. An output from each of the three coils is proportionalto the time rate of change of the ambient magnetic field.World Magnetic Survey - Goddard Space Flight Center

A Rubidium Vapor magnetometer is used to obtain accuratescalar field measurements. Combined with vector field data ex-trapolated from surface and airborne measurements, these datawill provide for a continued refinement of the mathematical de-scription of the Earthts main field and a measurement of thecontribution of the main field to the total magnetic field atany point in space. Time variances of the field will also bestudied to derive the diurnal and storm variations as seenabove the ionosphere. The orbit of the observatory should


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Galactic and Solar Cosmic Ray Study - University of MinnesotaData collected by this experiment will directly allow thedetermination of the energy spectrum of both galactic and solarprotons over the energy range from 40 Mev to 1 Bev as well asother particles over a comparable energy per nucleon range. Thedirection of the particle influx will also be determined. Byusing the Earth's field as a magnetic analyzer, the energy rangeis extended to 30 Bev for protons over the equatorial regions.Also, the experiment functions as a high counting rate monitor

for all radiation capable of penetrating 0.5 gm/cm2.The experiment consists of a mainbody detector orientedin the anti-Earth direction. The sensing device is composedof a scintillation crystal and a combination scintillation andCerenkov detector. The minimum detectable energy is governedby the crystal thickness and the amount of shielding. All par-counted


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LAUNCH VEHICLEThe 1,215-pound OGO-D satellite will be launched by the

Thrust-Augmented Thor-Agena-D into an elliptical near polarorbit. The orbit will be inclined to 86 degrees and has aperiod of 98.1 minutes.The launch vehicle consists of a Thor (LV-2A) first stage,three strap on TX-33-52 solid rocket booster motors and an

Agena-D second stage.Only one burn of the Agena's 16,000 pound thrust engine

is needed to place the OGO spacecraft in the required 259 by575 mile orbit. In order to allow the spacecraft to remainin sunlight during its first 48 hours in space, the launch willtake place during the first two hours immediately after dawn.Because only a single burn of the Agena is required, in-jection of the spacecraft will occur within radar sight of


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and launch through injection of the spacecraft into the properorbit. Launchings fo r Lewis are conducted by Unmanned LaunchOperations, Kennedy Space Center.FLIGHT SEQUENCE

The Thrust-Augmented Thor lifts off vertically with themain engine and the three strap-on solid motors firing. Thevehicle follows a programmed roll to the flight azimuth of177 degrees and a programmed pitchover to the proper trajectory.Both roll and pitcnover are controlled by Thor's autopilotprogrammer. The solid strap-on rockets are depleted at 43seconds into the flight and jettisoned at T plus 65 seconds.The radio guidarnce system begins to provide steering commandsat T plus 90 seconds.


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Deployment of the OGO experiment booms solar arrays andantennas will begin automatically about 15 seconds after separa-tion. Sun acquisition begins about two minutes after separation.

LAUNCH VEHICLE FACT SHEET

Liftoff weight 152,176 lbs.Liftoff height 97 feet

Thrust-Augmented Thor Agena Stage

Weight (at liftoff) 132,000 lbs. 16,000 lbs.


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THRUST-AUWMENTEDTHOR-AGENA FLIGHT SEQUENCEApproximate ApproximateLTime (see.) Altitude (miles)

1. Liftoff 02. Solid motor cutoff 43 73. Solid motor ejection 65 144. Thor main enginecutoff (MECO) 150 71


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-34-THE OGO-D PROGRAM TEAM

The following key officials are responsible for the OrbitineGeophysical Observatory satellite program:NASA Headquarters

Dr. Homer E. Newell, Associate Administrator for SpaceScience and ApplicationsJesse Mitchell, Director, Physics and Astronomy ProgramsMarcel J. Aucremanne, Program Manager, Geophysical Observa-tionsThomas L. Fischetti, Associate Program Manager, OGODr. Robert F. Fellows, Program Scientist

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Spacecraft design, development, fabrication and test,TRW Systems, Redondo Beach, Calif.

MaJor SubcontractorsBattery Cells, Gulton Industries, Inc., Metuchen, N.J.Gyroscopes, Minneapolis-Honeywell Corp., Boston, Mass.Horizon Scanners, American Standard, Advanced Technology Div.,Mountain View, Calif.Power Converters, ITT Industrial Products Div., San Fernando,Calif.Reaction Wheels, Bendix Eclipse Pioneer Div., Teterboro, N.J.


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ORBITING GEOPHYSICAL OBSERVATORYAPPENDAGE DEPLOYMENT SEQUENCE

2nd DEPLOYMENTi 1COMPLETED 1

I

(D

Ist DEPLOYMENTCOMPLETED

INJECTION

.L

REDUCED


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DATA |COMPRESSION TECHNIQUE

64,000 BITS/SEC TTAPESACQUISITION DATASITE PROCESSING 0IN EXPERIMENTER

50,000 BITS/FRAME[ | ~VISUAL CAMERA| .a r

-| COMPUTER

VIEW ONE YEAR'S DATA INONE DAYo * ~- m

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