NASA Facts Project Relay

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NASA FACTS(G-12-62)

An Educational Services Public:ation of the

National Aeronautics and Space Administration

PROJECT RELAY

Relay satellite superimposed on artist's conception of space .

Within five years, advances in space tech

nology may create an operat ional com munica

tions satell i te system that will vastly increase

intercontinental telephone, telegraph, and data

exchange channels and make possible transocean

television. Contributing to progress toward this

w communications era is NASA 's Relay satel

program.

Relay is designed to test intercontinental

transmission o f telephone, television, teleprint,

and facsimile signals vIa a medium-altitude

active-repeater sate II ite.

report on the functioning

on radiation in space .

It is also equipped to

of it s equipment and

Relay is th e first space communications experiment

designed to link three continents-North America, Europe,

and South America.



Medium-alt i tude IS an arbitrary designation

for altitudes from several thousand to about

2,000 miles. Active repeater signifies that

elay is equipped to receive, amplify, and

tra nsmit radio signals. Active-repeater satel

l i tes di ffer fro m passive co m m u n i cati ons satel

lites, such as Echo, in that the latter function

simply as mirrors for reflection of radio signals.

Relay is but one of several experimental

communications satellite projects embarked upon

by th e United States. The different technical

approaches of these programs are providing an

extensive variety of information that is advancing

th e t ime when establishment of on operational

system will be achieved.

INCREASING GLOBAL DEMAND FOR

COMMUNICATIONS SERVICES

Tremendous growth in oversea com'munications

demands is expected during th e next two dec

ades. The number of overseas telephone calls

to and from the United States is rising about 15

percent each year. Use of oversea teleprinter

xchange is cl imbing even more rapidly. De

and for world-wide television is mounting.

Computers are talking to each other from

coast to coast in growing numbers. As foreign

economies expand, a need is developing for

high-speed transmission of specialized data from

one side of th e world to the other and for data

origi nating in numerous oversea locations to be

fed into central ly located computer systems fo r

rapid processing and analysis. Existing trans

ocean radio and cable equipment cannot, for the

most part, su pply such services.

Radio and cable links currently furnish about

600 telephone circuits between the United Statesand abroad. Industry estimates that twice this

number will be needed in 1965 and that require

ments will double again by 1970. By 1980,

about 10,000 circuits may be needed fo r tele

phone and a few other services, not including

telecasts nor high-speed data transfers.

Although short wave radio an d undersea cable

il l continue to play an important part in future

ommunicat ion, they alone cannot meet future

needs. Keeping pace with global demand re-

NASA FACTS (G-12-62)

Symbol of modern overlond communications-a micro-

wave tower.

quires a vast increase in circuit capac i t y -an

increase possible through employment of micro

wave.

MICROWAVE-COMMUNICATIONS

SUPERHIGHWA Y

Microwaves are extremely short, ultra high

frequency radio signals that can carry at the

speed of l ight vast quantities of every known

form of com munication. Moreover, microwa'

communication is immune to weather and iono

spheric disturbances that interfere with short wave

radio. Within the continental United States and




Th is shows ho w a series of microwave towers spaced

about 30 miles apart on land can relay microwaves

around the earth ' s curvature.

A satellite can act as a microwave tower in the sky,

relaying microwave signals across oceons.

many other countries, microwaves are major car

riers of telephone, television, telegraph, punched

card, magnetic and punched tape, teleprinter,and facsimile communications .

In effect, microwave is to other electronic

communication methods in use today as a mod

ern expressway is to a neighborhood street.

However, microwaves, like l ight, travel in straight

l i nes-a serious l imitation on a round earth.

land, this l imitation is overcome by use of

re ay towers spaced about 30 miles apart so that

microwaves can move in a straight line from one

to the next. Admittedly, i t is impracticable to

build a l ine of microwave towers across the ocean.

But a communications satell ite such as Relay

functions as th e equivalent of a microwave towe

high in th e sky, enabl ing microwaves to vaul

oceans.

THE RELAY SATELLITE

The 172-pound Relay satellite is 33 inches high

and has a maximum breadth of 29 inches. The

18-inch long mast-l ike structure mounted on its

narrow end is the broadband antenna for carry

in g out television and other experiments in

broadband communications. The four whip-like

antennas projecting at about 45-degree angles

from the broad en d of the satell ite are for com

mand, tracking, and telemetry; that is , they are

part of the systems for turning Relay experiments

on and off, for tracking the satell i te, and for ac

quiring an d sending to earth data on component

behavior and on radiation in space.

The satell ite's eight sides are encrusted with

a total of 8,215 solar cells. These are photo

electric cells that absorb sunlight and convert it

to electricity fo r charging three nickel cadmium

batteries. Relay's power supply is designed to

permit communications experiments aggregating

100 minutes per day without excessive drain on,

and consequent damage to , the batteries.

Relay's orbit passes through zones of intense

radiation including part of the Va n Allen Radia

tion Region. Radiation can damage solar cells,

reducing their abil i ty to convert sunlight into

electricity. Except for some left unprotected fo r

experimental purposes, all of Relay's solar cells

are shielded against radiation by a thin layer o

quartz.

Relay has two receiving, ampl i fy ing, and

transmitting systems (transponders) for communi

cation experiments and tw o command systems by

which the transponder can be turned off and on

from the ground. This duplicat ion is one way

of increasing the chances that a spacecraft will

do its job. If a part fails, another is ready to

su bstitute for it .

Relay is designed to handle a single television

broadcast, 12 simultaneous two-way telephone

calls, or their equivalent in data, teletype, an d




Cutaways showing Relay satell ite interior from tw o angles .

1. BROAD-BAND ANTENNA I I . TRACKING, TELEMETRY , AND

2. SOLAR CELLSCOMMAND ANTENNA

3. TELEMETRY TRANSMlnERS12. THERMAL CONTROLLER

4. BAnERY CHARGE CONTROLLER13. RADIATION DAMAGE PANEL

5 . BAnERY BOX14 . RADIATION EFFECTS CIRCUITRY

6. CRUCIFORM STRUCTURE15. COMMAND RECEIVERS

7. RADIATION DETECTORS B,C,D16 . BROAD-BAND RECEIVERS

B. COMMAND CONTROL UNIT17 . COMMAND DECODERS

9. RADIATION SWITCH BOX HlB . TRAVELING WAVE TUBE

(Ampl ifying Device )

10 . TORQUE COIL19. PRECESSION DAMPER

(Adjusts Orientation)(Reduces Wobble)

Technician works on Relay satel l i te.

20.

21.

22.

23 .

24 .

25 .

MICROWAVE BEACONS26. SUN ASPECT INDICATOR

SIGNAL CONDITIONER (Indicates Satell ite Or ientation )

RADIATION DETECTORS E,F 27 . HORIZON SCANNER

VOLTAGE REGULATOR (Indicates Satellite Or ientotion)

TWT POWER SUPPLY 2B. RADIATION DETECTOR A

TELEMETRY ENCODER 29. RADIATION SWITCH BOX G

On August 31,1962, President John F. Kennedy signed

th e Communications Satellite Ac t of 1962 authorizing th e

creation of a communications satellite corporation. The

bill provided fo r half of th e stock in the new corporation

to be made ava i lable to the genera l public and half to

common carriers in th e communications field. The bill

also specified tha t public stockholders will elect si x of th e

company's directors; th e communications companies, si x;

and th e Government will appoint three directors . The

la w gave the Federal Communications Commission broad

powers to regulate rates and services, including alloca-

t ion of facilities to insure effective competi t ion.

Th e Act directed NASA to :

"1) advise the Federal Communications Commission

on technical characteristics of the communications satel-

lite system;

"2) cooperate with th e corporation in research an d

de ve lopme n t to the extent de e me d appropr ia te by the

Administra t ion in the public interest;

"3 ) assist the corporation in th e conduct of it s re -

search and development program by furnishing to the

corporat ion, when requested, on a reimbursable basis

such satel l i te launching and associated services as th e

Administration deems necessary fo r th e most expedit iousand economical deve lopment of the communications

satel l i te system;

"4) consult with the corporation with respect to the

technical characteristics of th e communications satellite

system;

"5) furnish to the corporat ion, on reques t and on

a reimbursable basis, satellite launching and associated

services reau i red fo r the establ ishment , opera t ion , and

maintenance of th e communications satellite system

approved by th e Commission; and

"6) to the extent feasible, furnish other services,

on a reimbursable basis, to the corporation in connection

with th e establ ishment and operat ion of th e system."




G iant horn antenna at Andaver , Maine , dwarfs man stand ing (center ) an one of its supports . This is be ing used

in Relay communications expe riments .

Braz i l i an en g i neers , stonding be fo re 30 -foot an tenna ,

confer on Relay exper i men t s. The antenna is part of atransportable ground station fo r space communications

experiments set up near Rio de Jane iro .

range of the test station, an automatic timer will

turn th e equipment off tw o minutes after use to

conserve the satellite ' s power supply. The test

stations are located at Nutley, New Jersey, an d

Mohave, California.

NASA 's world-wide Minitrack network is track-

ing the Relay satellite and acquiring data on

performance and condition of Relay equipment

and on radiation in space. The stations are lo-

cated at Blossom Point, Maryland; East Grand

Forks, Minnesota; Fort Myers, Florida; College,

Alaska; Mohave, California; St . Johns, New-

foundland; Woomera, Australia; Winkfield, Eng-

Iand; Johannesburg, Republic of South Africa;

Antofagasta and Santiago, Chile; Lima , Peru ; a




Quito, Ecuador . All stations funnel information

for processing to NASA ' s Goddard Space Flight

Center, Greenbelt, Maryland.

PRINCIPAL EXPERIMENTS

Planned communications experiments with

Relay include intercontinental transmissions of

television, telephone calls, teleprinter, photo

facsimile, and data. Arrangements have been

made with commercial broadcasting organizations

of Europe and the United States fo r public trans

atlantic telecasts. Public demonstrations involv

ing other types of communication are also

plan ne d .

Detectors within the satellite report the num

ber and kinds of energetic particles in space.

Such particles are free protons and electrons

stripped from atoms-usua l ly hydrogen atoms .

The particles constitute much of the lethal and

da maging radiation with which man and equip

ment must cope in space.

Another experiment is intended to determine

the effects of radiation on solar cells and semi-

conductors. Thirty solar cells mounted on the

es of the spacecraft are wired to report on their

dition . These solar cells differ in design and

material and in the amount of protective coating.

Some are unshielded.

In addit ion, six diodes are attached to a radi -

ation damage experiment panel where they are

exposed to the maximum radiation encountered

by the satellite. Ordinarily, diodes are enclosed

in packages within the spacecraft.

LAUNCH AND ORBITAL INFORMATION

A Delta vehicle launched a Relay satellite from

Cape Canaveral, Florida, at 6:30 p .m., EST, De-

cember 13, 1962. This satell ite's perigee, or

closest approach to earth, is about 820 miles;

apogee, or farthest distance from earth, approx

imately 4,612 miles . It is inclined 47.47 degrees

to the equator, enabling it to pass over a ground

rea extending from 47.47 degrees north latitude

o 47.47 degrees south latitude . Relay com

tes a circuit of earth about every 185 minutes.

Engineers at Cape Canaveral mate Relay satellite ta third

stage of its Delta launch vehicle.

This orbit ing of Relay was the fourteenth con-

secutive success fo r NASA's Delta launch vehicle .

Delta also launched Echo I, NASA's first com-

munications satellite; Telstar, the joint active

repeater satell ite experiment of NASA and theAmerican Telephone and Telegraph Company;

TIROS II through VI experimental weather satel

l itesi the Orbit ing Solar ObservatorYi Explorers

XII, XIV, and XV scientific satellites; and Ariel

built by the United States and United Kingdom,

the world's first international satellite.

The three-stage Delta vehicle ca n orbit satel

lites weighing as much as 800 pounds. It is

assigned a major role in future communications,

weather, and scientific satell ite experiments .




Second stage of Delta launch vehicle is hoisted to mate it with first stage on launch pad in background.

NASA FACTS format is designed fo r bulle t in-boord displayuncut , or for 8 x lOY, looseleaf notebook insert ion whencu t along dotted lines and folded along solid lines. For

notebook ring insertion, punch at solid dots in th e margins.

NASA FACTS will be mailed only to addressees who requestit from: Office of Educational Programs and Services, NASA,

400 Maryland Avenue, S.W., Washington 2S , D.C.

-tl u.s. GOVER NMENT PRINTI NG OFFICE ; 1963 Of-670374

For so le by the Superintendent of Documents, U.S. Government Printing OfficeWashington 25 , D.C. -Pr ice 15 cents per copy



: ; :L t )

.N 63 I e-r72

NASA FA ( TS(G-12-62)

An Educational Services Publication of the

National Aeronautics and Space Administration

Supplement

A REPORT ON THE FIRST RELAY COMMUNICATIONS SATELLITEJanuary 14, 1963

The first Relay satellite, launched December

13, 1962, could not at first function properly

because of an abnormal power drain on its

storage batteries. The problems relative to the

satellite had been partially resolved by January

3, 1963, making possible the beginning of ex-

periments in transatlantic communication.

On Relay's fifth orbit, some 14 hours afterlaunch, the ground test station at Nutley, New

Jersey, checked the satellite's condition. The

satellite's voltage was indicated at 22.5, which

is below the lower limit of 24 volts required fo r

operation of the communications equipment with

out damage to the battery.

The trouble was traced to the voltage reg-

ulator in the No. 1 t ransponder-the receiving,

amplifying, and transmitting apparatus in Relay.

Relay is equipped with two identical transpond

ers, each with its ow n voltage regulator. Thevoltage regulator channels power to the trans-

ponder at a proper voltage and acts as an on-off

switch for the transponder.

Telemetry showed that the regulator was con-

ducting power to the transponder even though it

was nominally off. As a result, it was partially

powering the transponder, and draining the

batteries. Extensive tests and analyses indicated

that the main power transistor for the voltage

regulator had temperature characteristics that

could account for the equipment's malfunction.This transistor fails to function properly i f it is

too hot or too cold.

Telemetry taken from the satellite on Decem-

be r 15, 17, an d 19 showed a slow charging

of Relay ' s batteries. Tests were suspended on

the possibility that Relay would recover.

On December 31, a check of the satellite re-

vealed that i t was functioning satisfactorily ex-

cept fo r a small power drain by voltage regula-

to r No.1 . Because of difficulties experienced

with the command system of transponder No.1 ,

project managers decided to employ the other

transponder. On January 3, 1963, they ac-

t ivated transponder No. 2 and carried ou t a

continuing sequence of transatlantic television,

telephone, and teletype communication tests.

Some difficulty has been encountered with thecommand system of the satellite. However,

techniques have been developed for satisfactorily

commanding the equipment.

Encouraged by the success of the tests, NASA,

in cooperation with broadcasting companies of

the United States and Europe, scheduled a pub-

li c telecast via Relay. On January 9, 1963,

Relay carried a television program from the Na

tional Gallery of Ar t in Washington, D.C., to

stations in France and Great Britain. British and

French viewers saw the unveiling of the MonaLisa painting in the National Gallery and Presi-

dent Kennedy and others who were present at

the unveiling ceremony. (Leonardo da Vinci's

Mona Lisa was loaned to the United States by

France.) Reception in Europe was excellent.

The television pictures from the gal lery were

transmitted conventionally to the Relay ground

station at Andover, Maine, from which they were

beamed to the satellite fo r retransmittal to

Europe.

A second Relay launch is scheduled in the sec-ond quarter of 1963.

USE OF THIS SUPPLEMENT

The Information In thl. supplement to NASA FACTS,

Project Relay (G-12-62) Incarparate. data on re.ults

obtained after th e fact sheet ha d been printed.

The supplement has been designed for bulletin board

display along with th e fact sheet, or for punching an d

looseleaf notebook Insertion as page 9 of NASA fACTS,

Project Relay.

u.s. GOVERNMENT PA INTING OFFICE : 1963 OF-57 !122

NASA Facts Project Relay

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