Ionosphere Beacon Satellite S-45 Press Kit

8/8/2019 Ionosphere Beacon Satellite S-45 Press Kit

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NEWS R E L E A S ENATIONAL AERONAUTICS AND SPACE ADMINISTRATION1 5 2 0 H S T R E E T . N O R T H W E S T . W A S H I N G T O N 2 5 , D . C .T E L E P HO N E S : D U D LE Y 2 - 6 3 2 5 . E X E C U T IV E 3 - 3 2 6 0FOR RELEASE: Briday PMls

February 3, 1961Release No. 61-16

NASA WILL LAUNCH IONOSPHERE BEACON SATELLITE (S-45)More knowledge of the ionosphere is the goal of a forthcoming

scientific experiment to be launched on a Juno I1 by NASA fromCape Canaveral

Several universities in the United States and New Zealandare participating in this experiment, intending to find out moreabout the shape of the ionosphere -- where there are concentrationsof electrons, where the ionosphere's profile has peaks or valleysin its structure.

So far, too little is known about the ionosphere, the ionizedfringe area over the earth's atmosphere, from 50 to several hundredmiles above the earth. Lack of thfs knowledge is costly in practicalapplications, such as long-range communications, which depend uponreliably bouncing signals o f f ionosphere layers.

The new payload being prepared for orbit is called theIonosphere Beacon Satellite S-45.Explorer VI1 and Explorer VIII, two t mcated cones back to back.

It looks very much like

The S-45, however, has a 6 - f o o t l o o p antenna around its equatorto transmit its low frequency signals to ground stations.


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Unlike Explorer VIII, this 74-pound satellite w i l l not bean experiment in itself. Explorer VI11 carried instrumentation fordiFect measurements of the positive ion and electron concentrationsin its orbital path around the earth.transmit on six frequencies (20 mc, 40 mc, 41 mc, 108 mc, 360rnc and960 mc).

The new satellite will1

Ground stations receiving these signals w i l l analyzethem by various methods such as change in polarization or Dopplershift to detemnine characteristics of the ionosphere. The satelliteis expected to orbit the earth every 115 minutes with an apogee ofabout 1,600 miles and a perQee of about 240 miles.

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The IonosphereUntil the beginning of space exploration, very little indeed

Until the advent of radio broad-as known about the ionosphere.casting, a generation ago, no one had seriously investigated theionosphere at all.the ground, much ionospheric theory developed before the age ofrocketry has since proven to be erroneous.

Since measurements were necessarily made from

United States rocketry has produced a tremendous amount ofdata about the ionosphere. Many miles of magnetic tape havebeen analyzed to date. This has resulted in findings that haveled to better methods in ionospheric research. Yet the surfaceof space, so to speak, has scarcely been scratched. When theobject is to map the whole ionosphere, its content from regionto region about the earth, its profile for hundreds of miles intospace, there must be a great deal of research.


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Rocket measurements have revealed the cause of radio blackoutsin high latitudes and crude means of predicting them have beendevised. These flights have brought about an explanation for theinexactness of previous methods for predicting maximum usablefrequencies for long-range communications circuits.

Rocket-gathered data have revealed serious errors made in thepast in the interpretation of data obtained by ground stations.This has stimulated the development of more accurate analysis ofthese data by modern electronic computers.

Experiments,must continue where unexplainable phenomena arerevealed.Peru, which is on a frequency of 108 megacycles.the night-time this station cannot get accurate tracking data.another station at East Grand Forks, Minn., signals vary greatly

A good example is a costly NASA tracking station at Lima,During much of

At

whenever satellites pass to the north after a severe disturbanceon the sun.

There is so far no explanation for these phenomena. Whenthere is one, it appears, it will be the result of scientificinvestigations.

New Zealand ExperimentOne example of the benefits which may be expected from greater

The two-islandnowledge of the ionosphere relates to New Zealand.dominion is remote from Europe'and America.between these continents and New Zealand are vital, and unfortunatelyfrequently beset with costly radio signal interference.

Radio communications


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- 4 -New Zealand's Seagrove Radio Research Station is one of the

participants in the S-45 experiment.Department of the University of Auckland.

It is part of the Physics

S-45 Program ParticipantsOthers participating are: Pennsylvania State University,

UniverSLty Park, Pa.; University of Illinois, Urbana, Ill.; CentralRadio Propagation Laboratory of the National Bureau of Standards,Boulder, Colo.; and Stanford University, Stanford, Calif

A part-time observing site has been set up at Baker Lake,Canadian Northwest Territories by the University of Illinois.Stanford University has set up a station at the University ofHawaii. The Pennsylvania State University has established anequatorial recording station near the magnetic equator at Huancayo,Peru.

Coordination and data reduction is the responsibility of NASA'sJ. Carl Seddon is the Goddard manager.oddard Space Flight Center.

TracMng, after the initial "quick look," will also be a responsi-bility of Goddard through its world-wide Minitrack network,

The first "quick look" at data to determine whether the vehicleis performing well and whether the satellite is going into thedesired orbit will be done by the NASA Marshall Space Flight Center.

The Marshall Center designed the payload, the first stagebooster, and is responsible for the launch vehicle, B i l l Greeveris the Marshall manager.


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- 5 -The launch vehicle chosen f o r this experiment t o be launched

from Cape Canaveral is the Juno 11, the 60-ton four-stage rocketused before in seven launch attempts, including the Pioneer I11and Pioneer IV radiation space probes, the Explorer V X I radiationsatellite, and the Explorer VI11 ionosphere satellite, Marshalldesigned the modified Jupiter first stage,were designed by the Jet Propulsion Laboratory.

The upper three stages

If the S-45 goes successfully into orbit, it will be assignedan Explorer name and number to indicate that it has joined theother 33 United States satellites which have contributed much tothe world's knowledge of the space environment.

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, .NATiQNAL AERONAUTICS AND SPACE ADMINISTRATION

WASWlNOTON 25, 0 . C.

Release No, 61-16-2 HOLD UNTIL LAUNCHFACTS ABOUT THE IONOSPHERE BEACON SATELLITE (S-45)

The S-45 satellite configuration is similar to those ofExplorer VI1 and VIII, It is in the form of two truncated cones,the bases of which are attached to a cylindrical band, or equator.The satellite structure is 30 inches in diameter, identical inthis respect to the earlier payloads; the height is 24 inches,six inches less than formerly,

The outer shell is constructed of aluminum, The fourth stagemotor case, after burnout, will separate from the satellite.

The instrwnentatirm consists o f the following items:1. Transmitter -- A single transmitter is usedto broad-

cast radio signals on six different frequencies at varying levelsof power, This is the largest number of frequencies to be usedby any satellite t o date, The basic oscillator frequency is1.00025 megacycles per second; the transmitting frequencies aresix harmonics (multiples) of this basic crystal frequency, rangingfrom 20 to 960 megacycles,follows:

The radiated frequencies are as


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Harmonic204041108360960

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Frequency Est, Transmitter Output Est. Radiated Power20,005 mc 300 mw 160 mw40,010 100 4041,01025 100 40108, 27 20 20360. 9 100 100960 40 10 10

By measuring at ground receiving stations the change inpolarization or the Doppler shift of the signals, it will bepossible to determine the ionosphere electron content between thesication and the satellite,

The six frequencies are developed from a 1.00025 mc. quartzcrystal oscillator. These frequencies are made to be extremelystable by a unique heat filter surrounding the crystal whicheliminates alternating changes in the crystal temperature as thesatellite passes from sunlight into eartlh's shadow, The transmitteris also unique in that it employs high-efficiency capacity diodeharmonic generators and transistor amplifiers to obtain an overallpower efficiency of 35 percent,

2, Telemetry and Power Supply --a. Telemetering will be done on the 108 frequency. A total

of 14 channels of information will be transmitted,temperature, 7 channels; satellite aspect, 2; voltage of exposedsolar cells, 2; voltage of main power supply, 1; calibration, 2.

They are:

b, The power supply will consist of both solar cells andnickel cadmium batteries to operate the payload continuously up to


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about 13 months, when an automatic timer i s scheduled to cut of ft h e t r a n s m i t t e r t o make t h e f r eq u enc i e s av a i l ab l e f o r o th e rpurpos es. Four packs of r echargeab le n i-cad b a t te r i es are locateda t 90 degrees apart on the equator of the s a t e l l i t e . The s o l ar c e l larrangement, on both the lower and upper cones of t h e payload, coversa t o t a l of 4665.6 square cent ime ter s (2592 c e l l s ) . The s o l a r c e l l sare covered individually w i t h a sheet of s i l i c o n glass , .0006 of aninc h thi ck, t o pr ot ec t them from ra di at io n. Nominal outpu t of themain power supply i s 15.4 vol ts .

c . Two add i t iona l pa tches of id en t i ca l unpro tec ted so la rc e l l s are mounted on th e ce nt e r band of the s a t e l l i t e i n tw o planes45 degrees apart atid 22.5 degrees respect ively f rom the tangentplane of t he s a t e l l i t e e qu at or . The pa tches cons i s t of 10 c e l l swired i n s e r i e s wi t h a to ta l pa tch ou tput of 3-l/2 v o l t s . As thes a t e l l i t e o r b it s , t h e r ed uc ti on of t h e vol tage output w i l l i n d i ca t ethe ex ten t of damage t o the uncovered c e l l s due t o radia t ion .Placed a t 45 degree angles t o each o ther , the patches w i l l a l s odouble as an aspec t sen sor when th e vol tag es of the two patchesare compared t o the known value which results f rom t h e sun 'ss t r i k i n g t h e s u rf aces a t a 90 degree angle.

d . Aspect Sensor -- While t h e exposed s o l a r c e l l p a tc he s(above) serve as a backup o r spare i n d i c a t o r of s a t e l l i t e a s pe c t,the payload incorporates a spec i f i c aspec t s ensor , tha t i s , aninstrument t o determine th e s a t e l l i t e ' s o r i en t a t i o n w i t h r espec tt o sources o f l i g h t . The asp ect system, loc ate d on th e paylo ad'sequator , uses tw o photodiodes, one se ns it iv e t o the sun's rays andthe o ther t o t h e ea r th ' s a lb ed o , o r r e f l e c t ed l i g h t .


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e. Temperature -- Seven temperature sensors are includedi n the payload, i n th e fol lowing locat ions: Two on protectedso la r ce l l s , one on exposed so la r ce l l , one i n a bat tery pack,two i n the tra ns mit ter , and one on the equa tor of t he s a t e l l i t e .Thus, fou r ext erna l o r s u n measurements and thr ee I nt er na lmeasurements a r e pro vid ed.

f . Antenna -- Two antennas are i n s t a l l e d on t he s a t e l l i t e ,both of which were developed by the Marshall Center, and are beingused f o r the f i r s t time. A loop antenna, s ix f e e t i n d i am et er ,extends from t h e s a t e l l i t e e qu at or soon a f t e r t h e f ou r t h st a gerocket case i s separated.force .The second i s a spike antenna, 19-3/4 inches i n length, which i smounted i n f ro n t of th e s a t e l l i t e a lo ng t he s p i n axis. The 108,360 and 960 mc s i g n a l s a r e t r an s mi t te d f r o m i t .

I t i s h el d i n p l a ce by c e n t r i f u g a lThe loop antenna radiates t h e 20, 40 and 4 1 mc f requenc ie s .

g . Payload Weight -- The weight o f the payload i s as follows:Ionosphere beacon antenna assembly 2.7 poundsUpper cone assembly 11.1Lower cone assembly 10.2Center ringShell assemblyInstrument columnSeparation deviceBattery packs ( fou r)

12.76.116.43.06.5

. . . - . . . - .... .. .. . - . . ~ . .. " .-. _... - "-1 ~ . I


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- 5 -WiringFastenersBalance weights

Total

2.73.0,6-

5.0 pounds

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATIONWASHINOTON 25 , 0 . c.

Release No. 61-16-3 HOLD FOR LAUNCHJ "0 I1 FACT SHEET

1s t Stage - Modified Ju pi te r . Booster sec tio n and pro pel lan t tanksextended three f e e t t o g ain 20 seconds burning time.F'uel - LOX and kerosene. Modification by Marshall SFC.Engine buil t by Rocketdyne Division of North AmericanAviation.

2nd Stage - Clus t er of e leven solid propellant motors , f i t t e d i n t ospin tub mounted on f i r s t s tage .

3rd Stage - Clus te r of th ree s o l id rocke t s .4 th S tage - Single solid rocket . (Three upper stages o r i g i n a l l y

developed by JPL f o r J u p i t e r C (Composite Reentry TestVehicle) B u i l t by Cooper Development Corp., Monrovia,C a l i f . )

Shroud - Over upper s tages and payload.Guidance - S t a b i l i z e c p l at fo r m i n b o os te r i s I t space-fixed" on ta rg et .

Deviat ions from a t t i t u d e s en s ed by sensors and a l te redby swivel l ing the rocket nozzle . B u i l t by FordInstrument Co.

Height of rocket - About 76 f ee t .Weight - 60 tons a t l i f t o f f .Speed ( a t burnout of f i r s t s tage) - 11,0'?0miles per hour.To ta l f l i g h t t i m e ( L if t of f t o o r b i t ) - About e i g h t minutes.


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- 2 -Inclination - 50 degrees to the equator.Apogee - About 1,600 miles,Perigee - About 240 miles.Period - About 116 minutes.Flight procedure - First stage burns out in about three minutes.

At burnout rocket is tilted into trajectoryangle. Booster separates from instrumentcompartment in a few seconds by explosivebolts. Retrograde rockets slow first stage,Upper stages coast before shroud is ejectedby explosive bolts and shunted aside bya kick rocket. Second stage ignites afterfive minutes, Third and fourth stages arefired in quick succession. Two minutes afterfourth stage boosts payload velocity todesired level, the burned-out motor case isseparated and the loop antenna is extended,

END


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. .NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

WASHINOTON 25 , 0 . C.

Release No. 61-16-4 HOLD UNTIL LAUNCH

S-45 TRACKING AND DATA A C Q U I S I T I O NThe Goddard Space F l i g h t Cen te r World-Wide Mini tr ack System i s

respons ib le f o r t racking the Ionosphere Beacon S a t e l l i t e S-45, usingth e 108 mc 'beacon frequency duri ng i t s ac t i v e l i f e - t im e of approxi-mately th ir te en months. Minitrack s t at io ns locate d a t Woomera,Australia; Johannesburg, South Afr ica ; Santiago, Chile; Antofbgasta,Chi le ; L i m a , Peru; Q u i t o , Ecuador; Antigua, B r i t i s h West Indies ;San Diego, C al if or ni a; F t . Myers, F lo ri da ; and Blossom Po in t,Maryland w i l l p a r t i c i p a t e using interferometer tracking techniques.The Winkfield, England and East Grand Forks, Minnesota Minitracks t a t i o n s w i l l be used f o r te lemetry acquis i t ion purposes only.

During the launch u d e a r l y o r b i t phases (defined as extendingfrom l i f t - o f f , through power f l i g h t , and f o r th e f i r s t t h r ees a t e l l i t e o r b i t s ) add it i ona l "quick look" trackin g data w i l l besupplied by t h e Marshall Space F l i g h t Center Doppler Station,Huntsvi l le , Alabama; the ARGMA Doppler Station, Redstone Arsenal,Alabama; the Marshall Space F l i g h t Center Doppler StatLon a t CapeCanaveral, Florida; the Goddard Space F l i g h t Center MinitrackS ta t i o n a t Cape Canaveral, Flo r id a ; the Goddard Space Flight Centerportable Doppler s tat ions a t Atlant ic , North Carolina; Paynters H i l l ,


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Bermuda; and Van Buren Maine; the Goddard Space Flight CenterMinitrack Stations at Blossom Point, Maryland; Johannesburg,South Africa; and Woomera, Australia; the Ballistics ResearchLaboratories Doppler Station at Aberdeen, Maryland; the FortMonmouth, New Jersey Doppler Station; the Jet Propulsion LaboratoryDoppler Station at Camp Irwin, California; the MassachusettsInstitute of Technology Lincoln Laboratories Millstone H i l lRadar Station at Westford, Massachusetts, and the Jodrell Bank,England, radio telescope.

The "quick look" tracking data obtained by the above stationswill be transmitted as soon as possible via electrical means to theMarshall Space Flight Center where it will be quickly evaluated andused in determining the Juno I1 vehicle performance, injectionparameters, and initial orbital elements. The "quick look" datawill also be transmitted to Goddard Space Flight Center where itwill be used, along with the Minitrack Direction Cosine Data, todetermine a more precise set of orbital elements and to computepredicted tracking and telemetry station acquisition times.

The satellite will transmit six frequencies which will allowexperimenters all over the earth to pursue ionospheric studies byground based observation of the satellite signals. The principalexperimenters and their observing station locations are as listedbelow:


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- 3 -M r . Fernandez de MendoncaRadio Science LaboratoryStanford UniversityStanford, CaliforniaDr. J. E. TitheridgeUniversity of AucMandAuckland, New ZealandMr. Robert S. LawrenceNational Bureau bf StandardsCentral Radio Propagation LaboratoryBoulder, ColoradoDr. G. W. SwensonDepartment of Electrical EngineeringUniversity of IllinoisUrbana, IllinoisDr. W. J. RossThe Ionosphere Research LaboratoryPennsylvania State UniversityUniversity Park, Pennsylvania

. I ,, , . - ,-,., . . . r . : I .

.$ ,.1 . sA . . . . . . I . . ..

The University of Illinois, Pennsylvania State University, andStanford University also have substations which are located inPeru, Hawaii, and Canada.

It is the responsibility of each of the above experimentersto publish the results of his research in technical journals and/orscientific reports.

The 108 mc satellite beacon signal will be used for bothtracking and f o r telemetering satellite aspect and environmentaldata. Telemetered data will be received by the Goddard Space Flight


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Ionosphere Beacon Satellite S-45 Press Kit