continues to develop within the context of our overall military communications needs.

As this committee knows, there are certain fundamental differences between military communications needs and civilian-commercial communications needs. In general terms, within the Department of Defense extremely tough and reliable but relatively low capacity service must be provided between a very large number of relatively smalloften mobile terminals, while most commercial needs are usually best served by higher capacity service between a lesser number of larger terminals.

Further, we have several particular concerns: protection against deliberate attempts to disrupt our circuits, their security, and the ability to furnish prompt and reliable communications between points that cannot always be predetermined.

I should also point out that the characteristics of a tactical communications system differ fundamentally from those of a long distance, point-to-point military system. Tactical operations call for communications circuits established with simple, highly mobile, equipments used by the deployed operating forces which permit literally hundreds of stations in the battle area to communicate with great flexibility and reliability on a random basis; a point-to-point network is considerably more fixed and is characterized by relatively higher continuous volume and a tighter network control.

The committee will recall that, in April 1965, the Department of Defense assumed responsibility for operation of NASA's synchronous satellite repeaters Syncom II and III. As you are well aware, Syncom II and III are developmental statellites and were not intended for long-term operation use.

But more recently, these satellites have been on station over the Indian and Pacific Oceans, respectively, and have been used both for R. & D. and operational test purposes and for emergency operational communications along routes including Hawaii, the Philippines, south east Asia, and Africa.

Syncom circuits have been used in support of the Gemini program however, the principal current use of these circuits is to provide alter nate, albeit quite limited, routes into southeast Asia. For example during the first week in August this year Syncom II was scheduled for over 90 hours of operations and Syncom III for about 120 hours Additionally, last week Syncom III was scheduled for about 10 hours of operation to help check out the installation of a Navy terminal or the U.S.S. Annapolis; we expect that Navy time allocations will in crease as this terminal becomes fully operational. Syncom III nor mally provides a single voice channel plus 16 teletype channels and Syncom II normally provides 16 teletype channels.

Turning now to the initial defense communications satellite project I am sure that this committee appreciates that I am gratified to re port a very successful first launch on June 16 of this year. You wil recall that, on August 8, 1964, the President announced plans for Defense satellite communications system and the Secretary of De fense directed the U.S. Air Force to initiate the space segment of thi program.

In October 1964, after a careful review of development plans the Air Force was authorized to proceed with actual developmen

of this space segment; the Air Force signed a contract with the Philco Corp. the same month and, thus, our first launch occurred just 20 months after the award of contract. As previously reported in testimony to this committee, we then estimated that the cost of the space segment development would be some $30 million. Currently, we are reasonably confident that its total cost should not greatly exceed this amount-with the increased cost attributable primarily to increased testing of the satellite and the dispenser. By early September, less than a month from now, a total of 22 satellites should have been tested and delivered to the Air Force ready for flight, thereby completing this particular satellite development program. Currently, nine satellites are available at Cape Kennedy ready for the second launch.

Our objectives in the IDCSP have continued to be (a) conduct R.D.T. & E. to study and demonstrate system operational feasibility; (b) establish an R. & D. system in being, convertible to an operational system; and (c) obtain an emergency capability to supplement the present Department of Defense essential command and control communications system. This R. & D. system was to consist of some 20 communications satellite repeaters in near-synchronous equatorial orbit and a number of ground and shipboard terminals sufficient to permit testing on a global network basis. The system was designed to provide a very few voice and teletype channels between any pair of ground terminals.

We chose the near-synchronous altitude to avoid certain operational problems in controlling a station-kept synchronous satellite, to increase low-latitude coverage relative to a medium-altitude system, and to reduce the tracking burden on the surface equipment. We also kept the satellite design as simple as possible to enhance the probability of long on-orbit lifetime. For economical reasons, we elected to use Titan III-C R. & D. boosters, manufactured by the Martin Co., to launch up to eight satellites at one time.

During the June 16 launch, the Titan III-C R. & D. booster performed in near-perfect fashion to inject seven communications satellite repeaters and one gravity gradient test satellite into circular, equatorial orbit at an altitude of approximately 18,000 nautical miles. The satellites were sequentially injected into orbit and each was given a small increase in velocity with respect to the preceding satellite. These differences in velocity cause the satellites to drift apart in orbit so that, today, the lead satellite is at 99° east longitude and the last satellite is at 122° west longitude; in other words, the satellites have spread out over some 221°. We expect the belt of satellites to close upon itself on September 21 of this year.

The telemetry data to date-and we now have 14 communications satellite-months in orbit-indicate a long potential communications lifetime. We shall be in a much better position to make lifetime estimates subsequent to the first satellite eclipse periods.

The gravity gradient test satellite is being used in an experiment being conducted as a cooperative effort with the NASA. This satellite uses an IDCSP spaceframe and gravity gradient stabilization equipment fabricated by the General Electric Co. The satellite is performing well and we have a successful experiment underway. Al

67-906-66- 2

though the telemetry data indicate that the oscillations accompanying launch are damping down, it is still too early to draw final conclusions regarding the utility of the gravity gradient stabilization technique at this great altitude.

Every effort is being made to see that the second launch of the IDCSP is equally successful. The 8 satellite repeaters placed in orbit with a successful second launch would establish a sufficiently large number of repeaters in orbit, 15 to permit full system testing on a global network basis. We are currently conducting limited tests with the initially deployed terminals and satellites, and expect to begin full system testing when all ground and shipboard terminals have been installed and completely checked out.

The Army's large terminals at Fort Dix., N.J., and Camp Roberts, Calif., are performing well and at present are carrying the major part of the test program. The Army is conductitng a ground terminal development program with the Hughes Aircraft Co. The first of the resulting AN/MSC-46 terminals already have been deployed to Africa, Germany, Hawaii, and the Philippines.

The Army is now experiencing some difficulties in the initial operation of these out-of-country terminals but expects to have them resolved shortly. The Army is developing a smaller ground terminal, the AN/TSC-54 at Radiation, Inc. First delivery is expected early next year. As an example of how we would use the system operationally, this fall we are deploying terminals to southeast Asia to give us a capability of handling minimum essential traffic if all other communications means fail.

The Navy is developing a shipboard terminal, the AN/SSC-3, and expects to have the first shipboard installation ready for operational testing in October. The Navy is procuring several AN/SSC-3's, with the last terminal expected to be operational early in 1967; these terminals are also being procured from the Hughes Aircraft Co.

A third, backup, IDCSP launch is presently scheduled for next year; however, the launch could be moved ahead in the event of a catastrophic failure on the second launch. Alternatively, this booster and its payload of eight satellite repeaters could also be used either to replenish or augment the initial space segment; how it will be used depends upon our experience with the satellites in orbit, the overall circuit and network behavior, the eventual operational demands for satellite communications service, and the advanced operational system schedule.

A fourth Titan III-C launch is also planned for early 1967. The payload for this launch contains three IDCSP satellites and three experimental satellites. The additional IDCSP satellites will serve to replace satellites that may have failed, thereby assuring that a useful number of operating satellites remain in orbit. The experimental satellites are (a) one to conduct an electronically despun antenna experiment; (b) another to investigate gravity gradient stabilization further; and (c) an ultra-high-frequency (UHF) communications repeater to be used in the tactical satellite communications program that I shall describe shortly.

The electronically despun antenna is a technique both for directing the satellite radio energy directly toward the earth rather than radiating most of it into space and for more efficient collection of transmis

sions radiated toward it from the earth's surface. This experimental antenna is being developed by Sylvania Electronic Systems Division and is incorporated into an IDCSP satellite repeater. As you know, the IDCSP satellites are spin-stabilized and, therefore, to point an antenna beam at the earth we must electronically spin the antenna beam at the same rate as, but in the opposite direction to, that in which the satellite is spinning.

The gravity gradient stabilization satellite, known as the DOD gravity experiment, or DODGE, is a larger and more sophisticated experimental spacecraft than the one placed in orbit on the first IDCSP launch. This satellite, being built by the Applied Physics Laboratory of The Johns Hopkins University, will be used to investigate three axes-pitch, roll, and yaw-stabilization.

If we are able to stabilize a nonspinning satellite so as to have it alined with the center of the earth, we could then employ a large fixed antenna on the satellite, thereby, as in the case of the despun antenna, greatly improving the effectiveness of the repeater.

The experience and knowledge gained from conducting these experiments will be most valuable in selecting the satellite design in the ADCSP which, in turn, will affect the design of the operational system terminals.

We realized at the outset of our initial R. & D. program, that it was a sharply limited one and, as good R. & D. experimental programs should be, had important elements of speculation and risk. We also appreciated that satellite communications technology was advancing rapidly, as was our knowledge of the proper role of satellite communications in the whole family of communications methods available to the Department. We therefore set ourselves the goal of establishing, at the earliest prudent moment, a truly efficient and effective advanced operational satellite communications system as part of the overall defense communications system-a system which would take full advantage of our experience with Syncom and IDCSP circuits and of general technological advances to meet our truly unique and vital long-distance military trunk requirements. Since Dr. Foster's report to you on this aspect of our overall program, the Defense Communications Agency, assisted by the military departments and my office, has completed system definition studies for such an operational system. The DCA has forwarded its recommendations to the Joint Chiefs of Staff for their formal review and recommendations to the Secretary of Defense.

At the present time, the Joint Staff is reviewing the DCA plan in the context of our overall military communications needs. They are examining the fundamental characteristics of the system to be certain that it will serve the proper terminal areas, that it will do so with the required capacity-reliability product, that it will be a tough flexible and secure system, that it will be properly related to other military circuits and systems-the land and undersea cables, high-frequency radio networks, line-of-sight and scatter circuits, and commercial satellite communications circuits. They are studying its characteristics not only as they are related to the preparation of the first study plan, but also to their communications experience since that timeespecially within the NATO and in southeast Asia.

Assuming a favorable review by the Joint Chiefs, and continued success with our IDCSP research and development program, we still expect as Dr. Foster testified in January-that the Department could initiate contract definition studies for the various space and surface segments during fiscal year 1967.

In this regard, we have already approved the development of a new Titan III-Č nose fairing which would allow future models to carry a much greater payload weight into high orbit.

Our work in the application of spacecraft repeater technology to military tactical communications needs has been progressing with increased emphasis during recent months. Studies conducted by the military departments have definitely shown that there are a number of significant operational needs for tactical communications which are not now satisfactorily fulfilled by available means and which lend themselves to the application of satellite relays. It is anticipated that any use of such repeaters would result in particularly marked improvement in the reliability, security, and flexibility of those tactical radio communication circuits now established in the high-frequency portion of the frequency spectrum.

The military departments are now actively implementing a joint research and development program, the so-called Tacsatcom program, approved by the Director of Defense Research and Engineering earlier this calendar year. This program is oriented toward determining how the use of space communications relays can contribute to providing the fluid and flexible response normally associated with the military communication needs of highly mobile, low echelon land formations (corps and below) and analogous air and sea operations. Close attention must be given to such problems as the relative advantages and disadvantages offered by various portions of the frequency spectrum; the potential sources of interference in the ultra-high-frequency (UHF) portion of the spectrum; the technical and economic practicalities of modifying or replacing present tactical communications inventories; the complexities of relating certain present communication procedures that differ among the services; operations network control; and the technical-operational-cost trade-offs between space and earth components where simplicity, limited size, and light weight are prime considerations for the latter.

The Air Force has accomplished important exploratory development work in such areas as phased array antennas for aircraft, and radio wave propagation studies, and has conducted a number of experiments utilizing two experimental satellites designed and fabricated for them by the MIT Lincoln Laboratory and launched last December by a development model Titan III-C. Although these two satellites, called LES-3 and LES-4, were placed into an elliptical orbit of 18,000 by 100 miles instead of the desired circular near-synchronous orbit because of a booster transstage malfunction, useful early experimental data have been obtained.

Of particular value were measurements of the time delay and amplitude of the multipath components of transmissions made between satellites and airborne terminals, test of a magnetic torquing technique that could be used for proper orientation of solar cells with respect to the sun, and satellite antenna beam-switching in the SHF portion of the frequency spectrum. The Navy's satellite communica