The U.S at UNISPACE '82 Satellite Communications Booklet

8/14/2019 The U.S at UNISPACE '82 Satellite Communications Booklet

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NAS 1. 2 : Un3/ 3

Vienna, Austria1982

The U.S. at

UNlsPACE '82Satellite Communications


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A 3 mete r dia. ant enn a use d in India to receive television fro m

ATS-6.

Due to the successes of satellites in providing reliable, affordable international communications on a worldwide basis, they havebecome increasingly important in domesticand regional communications. Early experi-ments in space communications were conducted by the United States, largely throughthe National Aeronautics and Space Administration (NASA) in cooperation with the American communications industry.

The United States, through The Comsat

Corp., played a major role in the formation ofThe International Telecommunications Satellite Organization. INTELSAT is the body thatowns, maintains and operates the global satellite system which is used by countries aroundthe world for public international telecommunications services.

CTS.

The demand for satellite communicationscontinues to grow for television, telephonyand data. Technical developments promise toexpand capacity to meet these demands. New

research into higher frequencies, satelliteclusters and large platforms is continuing.Narrowband communications to small earthterminals for the developing nations of theworld will be available in the near future. TheSpace Shuttle will help to make these satellite services economically available.

The United States continues to pursue thepeaceful uses of space in the spirit of boththe 1958 U.S. NASA Space Act, The ComsatAct of 1962, and the 1967 U.N. Resolution onOuter Space.

SUMMARY


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DEP0SITORYMATERIAL

SEP 10198 2

Pioneering Space Communications JOHNcOTTONDANILBRARYRUTGERS-THE STATE UNIVESITY

Telstar 1 & 2, launched in the early 60's intolow altitude orbits, were the first communications satellites to use active repeaters. TheseAmerican Telephone & Telegraph satelliteprojects developed spacecraft repeaters andassociated earth stations operating in the 6/4GHz frequency band. These technology developments led to the current satellite systems.

The SYNCOM Program first demonstratedthe advantages of geostationary satellitecommunications. SYNCOM was followed byadditional NASA programs: the ApplicationsTechnology Satellites (ATS) and, with Canada,

the Communications Technology Satellite(CTS). The ATS and CTS programs resulted inan increased awareness of the potential ofsatellites for the delivery of health and educational services, broadcasting, mobile communications and the use of economical earthstations.

ATS-1 and ATS-3Launched in 1966 and 1967, ATS-1 and -3

are still operating. They have provided the developing South Pacific with more than 100health, education and emergency experiments. One ATS experiment is "Peacesat,"which emphasizes wide-area coverage, two-way voice links and small, inexpensive earthstations.

ATS-3 has been used for emergency mobilelinks in remote areas, for medical servicesand for other experiments in the Caribbeanand Antarctic regions.

ATS-6 and CTSATS-6, launched in 1974, demonstrated the

capabilities of high power levels in satellites.The body-stabilized satellite relayed high-quality signals, including color TV. In its second year, ATS-6 performed the Satellite Instructional TV Experiments (SITE) in India,broadcasting programs on agriculture, health,hygiene, science and family planning to fivemillion people in 2400 villages. Later, 27 other

developing nations experimented with ATS-6as it transited back to the Western Hemisphere.

ATS-6.

The Communications Technology Satellite(CTS), a joint Canadian/U.S. project^ launchedin 1976, pioneered the use of the 14/12 GHzband. CTS provided valuable experience indelivery of TV to small, low-cost earth stations in remote areas. This led to operationaluse of this band by many existing and plannedsatellites.

"Peacesat" Map.


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RELIABLE COMMUNICATIONS HARDWARE AVAILABLE TO TH

Antennas for sale.

SBS.

The U.S. has become a "telecommunica-tions bazaar," as users from around the worldshop openly for hardware, choosing from themany options available at competitive pricesand terms. Extensive resources have been invested in research and development, as wellas on operational systems, advancing thestate of the satellite communications art. The

fruits of this effort are now available.American hardware is inexpensive, reliableand widely available. As the U.S. competes ina free and open marketplace to meet theworld's needs, the prices of earth stationhardware continue their decline. Componentsmay be mixed and matched to form customsystems. Turnkey installations are availablefrom many American manufacturers. Thetechnology has been well-proven, and tyoicalprices for TV receive-only terminals rangefrom US$2,000 to US$10,000. There are nowabout 50,000 such small terminals in the U.S.

Satcom l.


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WORLD

Intelsat V.

Companies that originally made experi

mental satellites now have spacecraft hardware available "off the shelf." These satellites are modeled after highly successful U.S.domestic satellites such as COMSTAR,SATCOM, SBS and WESTAR. These satellitesare operated by U.S. communications common carriers under licence from The FederalCommunications Commission. SATCOM satellites helped create a domestic market forsmall, inexpensive, television receive-onlyearth stations.

High-power satellites modeled on CTS are

emerging as the age of direct-to-home broadcasting arrives. These direct broadcastingsatellites can deliver TV signals to home antennas smaller than one meter in diameter.

Advances in technology can continue tomake better and more efficient use of orbitand spectrum resources. The newest operational satellites, now under construction, willhave triple the capacity of the first-generationdomestic satellites. Spacecraft are availablein several sizes and capacities to fit theneeds of individual nations. The illustrations

show a few of the satellites available.

G Star.

TDRS.


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SYNCOM & INTELSAT: PARENT & CHILDREN

Since the beginning of the U.S. space communications program, the application of satellites for the benefit of mankind has beenone of NASA's major objectives. The Communications Act of 1962 mandated U.S. policy to"serve the communications needs of theUnited States and other countries and . . .contribute to world peace and understanding."

Uniting MankindArthur C. Clarke, who first proposed the use

of the geostationary orbit, said, "I believe thecommunications satellite can unite mankind."Truly, the INTELSAT System is doing just that.As satellites become more complex, groundhardware becomes simpler, and the widespread use of satellite communications becomes commonplace. Advances in technologyprovide improved communications, a primeingredient for improving the quality of life forall people.

Today, the INTELSAT System provides

global and domestic communications to morethan 100 countries. These high-quality, reliable services are available on a nondiscriminatory basis to all areas of the world.INTELSAT I ("Early Bird") was a modif ied version of SYNCOM III, the world's fi rst geostationary satellite. SYNCOM vastly simplifiedearth station technology by making non-tracking antennas possible. The expensiveacquisition and tracking antennas for non-geostationary satellites were no longer nec

essary, widening the use of the INTELSATSystem.INTELSAT I, the first commercial communi

cations satellite, had a capacity of 240 telephone channels. INTELSAT VI, due for launchin the late 1980s, will carry several televisionand 33,000 voice channels. The demand forsatellite communications has prompted concern over the possible saturation of the geostationary orbit and the allocated frequencybands. Technological advances promise toexpand the newer satellites' capabilities tomeet this expected demand.


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THE FUTURE

Satellite technology development continues. Satellite capacity was doubled by theuse of cross-polarization, doubled again bythe use of the 14/12 GHz frequency band, andfurther increased by additional frequency al-locations. "Spot" beams, with onboardswitches, permit extensive reuse of the frequency bands. The 30/20 GHz band, with fivetimes the allocated bandwidth of either of theother two bands, promises a substantial in-crease. Currently, the U.S. is designing satel

lites to work with small, affordable terminalsover widespread areas. This technology canbe used to link small mobile terminals; such a

joint Canadian/U.S. program is being plannedto reach land vehicles throughout NorthAmerica.

LASER INTERSATELLITE LINK TECHNOLOGY

Expanding Orbit/Spectrum CapacityNASA's Advanced Communications Tech

nology Satellite Program, planned for the late1980s, will develop inter-satellite links and onboard signal processors, and test new bands,multiple spot beam antennas, and new modulation techniques. Such techniques will continue to provide means of expanding the orbitand spectrum capacity, and make newercommunication systems and networks available to developing nations.

Future satellites may operate in clustersand eventually be aggregated onto largespace platforms, such as the one picturedhere. These will be constructed in orbit usingthe Space Shuttle, which may also be used torepair and ser ice satellites in orbit

Geostat ionary Communicat ions Platform.

The Space Age has just begun. There re-mains a long road to travel, and the challengeexists to make outer space still more accessible and affordable. In this regard, the U.S. iscommitted to maintaining a strong space R&Dprogram.

In carrying out its national and international space activities, the U.S. adheres tothe principles of peaceful use of outer spaceembodied in the National Aeronautics andSpace Act of 1958, which established NASA,as well as those of the subsequent 1967United Nations Treaty on the Exploration andPeaceful Uses of Outer Space.

Shutt le Launching Satel l i tes.


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NASANat ional Aeronaut ics and Th e Space ShuttleSpace Admin is t ra t ion Lifts Off Into Space

The U.S at UNISPACE '82 Satellite Communications Booklet

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