established. Techniques which are being considered for such a network are medium-altitude and high-altitude systems. Both systems contemplate the use of active repeater satellites in orbit to receive, amplify and retransmit radio signals in a manner similar to present overland microwave relay repeaters.

Medium-altitude satellites would orbit several thousand miles above the earth, in a polar or equatorial orbit generally in the 4,000 to 8,000 mile range in an operational system. Experimental trials for the testing of such satellites during 1962 include Project RELAY of NASA, on which RCA is the prime contractor, and Project TELSTAR, which is a cooperative undertaking between NASA and AT&T.

High-altitude or synchronous satellites would be placed in equatorial orbit about 22,300 miles above the earth. At this altitude, the speed of the satellite reaches the speed of the earth's rotation, so that the satellite remains fixed in relation to the earth's surface. Project ADVENT of the Department of Defense and Project SYNCOM of NASA propose to test synchronous satellites during 1962 and 1963.

Government and industry research and development activities during the coming year should provide much additional scientific knowledge relating to communications satellites. Technical problems on which facts are needed for the development of an operational system include (a) location, strength, and significance of damaging radiation, including life expectancy of satellites operating in the space environment; (b) how to achieve reliable control and stabilization of attitude; (c) how to achieve reliable positional control in orbit; (d) how to place heavy pay loads into high equatorial orbits; and (e) significance of time delay due to long transmission paths, and appropriate corrective measures for echo.

Communications by use of medium-altitude satellites may be achieved at an earlier date than by use of synchronous satellitesalthough differences of opinion exist in this respect. It appears that the system which can be established first on a practical basis depends upon the outcome of further research and development. Mediumaltitude satellites involve less time delay in transmission for telephone

service than do synchronous satellites. The round-trip delay between New York and London (i.e., the time within which a speaker cannot receive a reply to a remark) would be approximately .14 to .19 seconds for a medium-altitude satellite and .53 seconds for a synchronous satellite. This compares with a delay of .07 seconds over existing cable facilities between New York and London. Whether the time delay would be objectionable to telephone subscribers is a matter of current study and analysis.

The medium-altitude technique requires that each ground station. have access to computing and tracking facilities to determine the position of each satellite so it can be followed with directional antennas as it moves in orbit. Each medium-altitude satellite would be usable in a practical sense for communications between only two or a limited number of areas at any one time in its revolution around the earth.

It has been suggested that a network of 20 such satellites in polar orbit may be desirable to serve heavy traffic routes, where comparisons may be made between the quality of service via satellites and over other facilities, and to provide flexibility to serve other points with more limited traffic requirements. Capacity of the system would be the equivalent of 1000 or more telephone circuits between any two areas for telephone and telegraph services and for television transmission.

High-altitude or synchronous satellites would remain fixed at all times within operational view of many ground points. Two pairs of these satellites could link the major international communications areas of both hemispheres; three pairs could cover the inhabited part of the world with substantial overlapping. Ground stations at each location within view of a synchronous satellite can be used for direct communications with all other ground stations through the satellite relay. They would employ fixed antennas without tracking facilities. The simplicity and lower cost of ground stations, and the ability to obtain independent access to the satellite relay from many ground stations located where convenient and desirable, make the technique attractive for use by many countries having high or low traffic requirements.

Three pairs of synchronous satellites have been suggested as a global network to provide light and heavy route service for countries

82357 0-62-pt. 2- -17

throughout the world. One pair of such satellites would be positioned in equatorial orbit generally over the Atlantic Ocean for transatlantic and Latin America service, another pair over the Pacific Ocean for transpacific service and a third pair over the Indian Ocean to serve countries in that area. Each of these satellites could be used simultaneously by many countries through their own ground stations within operational view of the satellite. Each satellite would have a capacity equivalent to 1,000 or more telephone circuits. Two such satellites at each location would provide telephone and telegraph services and also television transmission service.

It has been suggested also that an operational system may take the form of 6,000 mile polar orbit satellites supplemented by 22,300 mile synchronous satellites to create a combined system; or, if they become available soon enough, successful high-altitude satellites may obviate the need to place more than a few experimental satellites in medium orbit. On the other hand, transmission considerations may dictate extensive use of medium-altitude satellites even after high-altitude satellites have been perfected and placed in service.

The choice of communications satellite system design will be made in the light of the best information available from further research and development. On the basis of information to be obtained from experimental trials, further development, design and manufacture, it may be feasible to establish an operational system by 1965 utilizing medium and/or high-altitude satellites. We expect that an operational system would be established initially by utilizing whatever satellite first proves most rewarding and then progressing to improved satellites in more difficult orbits as this becomes feasible. In this manner, a system should be achieved having the best features obtainable.

Cost Parameters.-The initial investment required to establish an operable communications satellite system cannot be stated precisely at this time. Estimated capital cost parameters for various configurations of satellites are as follows:

Configuration

(a) 20 medium-altitude satellites in random polar

orbit

Cost*
($ million)

45 to 94

(b) Two pairs of satellites in synchronous orbit...... 50 to 100

(c) Configuration (a) plus 10 medium-altitude

satellites in random equatorial orbit......

67 to 141

(d) Three pairs of satellites in synchronous orbit 75 to 150.

These estimates do not include the cost of ground stations, replacing satellites or otherwise maintaining a going system.

General cost parameters for the construction of ground stations range from $6.5 to $9 million for each ground station serving heavy traffic areas in a medium-altitude system (plus $7 million for an associated tracking station to serve the system) and $2.5 to $3 million for each ground station serving a high-altitude system. On this basis, capital costs to establish ground stations (not including annual operating, maintenance and replacement costs) to serve initially ten pointsfor example, east and west coasts of the continental United States and in Hawaii, and seven foreign countries-by medium and/or highaltitude satellites would be as follows:

Medium-altitude satellites are estimated to cost $450,000 to $600,000 each and high-altitude satellites from $1 million to $2 million each. Rockets for launching satellites will probably range from $9.5 million for the Atlas-Agena B to $10.5 million for the Atlas-Centaur or modified Atlas-Agena. These costs include $1 million for use of a launching pad, launch tracking and associated costs. It has been assumed that the Atlas-Agena B would have an 80% probability of success in launching three medium-altitude satellites and the AtlasCentaur would have a 66%% probability of success in launching ten mediumaltitude satellites. It is estimated that a modified Atlas-Agena B would have a 50% probability of success in launching high-altitude satellites. The cost per satellite in space would also depend upon the number of satellites that could be launched with a single rocket. This could vary from one to two satellites per launch for the high-altitude system and three to ten satellites per launch for the medium-altitude system.

Allocation of Frequency Bands.-The Ordinary Administrative Radio Conference of the International Telecommunication Union, Geneva 1959, allocated frequencies to be used for space research, including satellite communications. International agreement on the allocation of frequency bands on a regular basis will be necessary for the establishment of an operational satellite system. Preparatory work and further studies are being carried on looking toward the allocation of such frequencies at the proposed 1963 Extraordinary Administrative Radio Conference. Preliminary views of the United States in preparation for this Conference have been formulated. It is proposed to allocate a total of 2975 mc/s of spectrum space for communications satellite service in the bands between 1,000 and 10,000 mc/s.*

C. Communications Requirements to be Served.

Public interest objectives in the establishment of a communications satellite system include (a) the making available of new and expanded communication services at the earliest practicable date, (b) providing a potential for an efficient global communications coverage as soon as technically feasible, and (c) establishing a commercially operable and economic system.

We believe that the communications satellite system initially should provide all types of voice and record communications point-to-point services, i.e., communications services between two or more ground

See In the Matter of an Inquiry into the Allocation of Frequency Bands for Space Communications, FCC Docket No. 13522, Second Notice of Inquiry, released May 19, 1961 (FCC 61-652).