Mr. ROBACK. What are the potentials for operational use? I am talking now of, on the one hand, VHF and, on the other, the micro

wave.

Mr. JAFFE. Well, since there are numbers of experimenters on each of these requiring various lengths of time, we don't really know definitely how long each of the experimenters will require until you get into this experimental phase and determine what the problems really are. It is very difficult to say when you could discontinue making experiments available, or making the facility available.

Mr. ROBACK. You are going to experiment yourself out of this problem?

Mr. JAFFE. I would like to right now. But it is a very difficult thing. In Syncom we actually found that we were through the experimental period much earlier than we had had contemplated. However, this is a much more difficult mission. Syncom was merely an experiment with a very simple transponder to get into the 24-hour orbit. It had never been done before and it was basically a spacecraft experiment, just to obtain the synchronous orbit. There was not much of highly technical interest in the transponder.

This is not the case in ATS. There are a dozen or so experiments being performed with the ATS spacecraft, and I can supply for the record a list of these experiments, all requiring the use of power.

Mr. ROBACK. Do so.

NOTE. In addition to the above requirements, approximately 20 watts is required for spacecraft housekeeping, telemetry, and the like. The period control requirement of 14 watts per jet can be met by the storage batteries due to its sporadic use.

Initial bus power on ATS-B and C is nominally 180 watts at 90° solar incidence degrading to 169 watts after 500 days. For worst angle of solar incidence these fall to 165 watts and 155 watts respectively. Corresponding figures for ATS-A, D, and E are:

135w-123 watts and 124w-113w

Mr. JAFFE. There are experiments which do require long-term observation. The meteorological experiment requires long-term observation. The VHF experiment requires long-term observation.

OPERATIONAL USE OF ATS

Mr. ROBACK. Let us suppose, for the sake of discussion, that in 2 years you have a pretty good wrapup on your experiments, and your design expectations will be met or exceeded as far as satellite lifetime goes. What do you do then?

Mr. JAFFE. I don't know.

Mr. ROBACK. You don't know. This will be somebody else's worry. Mr. O'Connell invited you to resubmit an application if and when your experiments were done. He offered it here in his testimony. In other words, he didn't necessarily foreclose forever the use of this for some purpose if you could demonstrate the need for it.

Mr. JAFFE. I assume if such needs were in the national interest and were strong enough, that these satellites could be put to use.

Mr. ROBACK. But as the matter stands now, you would have to get some further policy decision before you could turn this over for a Syncom-type traffic operation that is presently employed?

Mr. JAFFEE. Yes.

Mr. ROBACK. What attention did you give to the problem of utilizing the ATS for NASA traffic requirements? Suppose there had been put upon you the objective of supplying Apollo air-ground, I mean the traffic communications and pilot communications. Could you have used this resource for that purpose?

Mr. JAFFE. We looked very seriously at this possibility, and in view of the hard requirement, the very hard requirement for availability of service, and reliability of the Apollo program, the experimental and highly speculative nature of the applications technology satellite, and in view of the experimental requirements over the immediate future, it was decided that it could best be done with an additional spacecraft, and not to try to devote the ATS spacecraft to this particular use.

Mr. ROBACK. You didn't want to compromise your experiments. Mr. JAFFE. That is only part of it. We could also, because of the size of the spacecraft, the large advance in technology contained in

ATS, over and above that required for the Apollo program, it was not desirable to rely on the success of that spacecraft.

Mr. ROBACK. We are not talking about a single use of the spacecraft for pilot communications. With all the capacity that is involved, why couldn't you have dedicated a portion of it, so to speak?

Mr. JAFFE. Again, the only

Mr. ROBACK. I mean, it makes sense, doesn't it?

Mr. JAFFE. The only requirement at the time was the requirement of the Apollo mission, and the Apollo mission is a requirement that is a very hard requirement. It must be met, and it must be met with a great deal of reliability.

Again I would like to state that ATS does represent a significant advance in the technology. It has never been flown. It is not merely a factor of two or three extensions of Syncom, and to rely on that for an operational utilization by NASA, I think, would have been a mistake. Mr. ROBACK. Let us say, and nobody is wishing any bad luck-but let us suppose that Mr. Sohier has to exercise the default clause. Can you hook onto ATS?

Mr. JAFFE. We will not have ATS spacecraft in orbit, more than one in orbit at the time, and it will be placed over the Pacific. There wil' be no Atlantic ATS spacecraft at that particular time.

Mr. ROBACK. But conceivably, you could get part of your traffic re quirement. Maybe you could make a deal with the Defense Depart ment also.

Mr. JAFFE. Conceivably, if this has to be pressed into service, and if it exists over the Pacific, it could be pressed into service for a portion of their requirements. I am not sure whether it takes care of the entire requirement.

USE OF NUCLEAR POWER SOURCES

Mr. ROBACK. Why didn't you, in view of the power constraints that you tell us about, why didn't you put an advanced concept of power in the ATS?

Mr. JAFFE. This spacecraft is designed to take maximum advantage of the launch vehicle, which is the Atlas-Agena, and designed to get about as much power with as much volume as one can get with that launch vehicle into the 24-hour orbit.

Mr. ROBACK. You are talking about a conventional power source, that is to say, an established power source?

Mr. JAFFE. It is true we are still talking about solar cells, yes. Mr. ROBACK. If this is advanced in so many ways, why didn't you strike out in the power field? Isn't it a fact that power is going to be your limitation on all these space experiments in the 1970's? Mr. JAFFE. Yes.

Mr. ROBACK. You said so, in effect.

Mr. JAFFE. Yes.

Mr. ROBACK. You are talking about broadcast satellites, for example: you are going to need a new power source, aren't you? Mr. JAFFE. Probably.

Mr. ROBACK. Is your power development keeping pace?

Mr. JAFFE. I think it is. There is so much in any particular time that one wants to design into an experimental vehicle or into an ad

vance; in this particular time scale it is not desirable, in my opinion, to develop new power sources on the ATS vehicle.

Mr. ROBACK. What about the ATS-II? I don't mean the second vehicle, I mean the second generation.

Mr. JAFFE. The second generation is still in the design stage, still open for question.

Mr. ROBACK. You are making feasibility studies?

Mr. JAFFE. We are making feasibility studies.

Mr. ROBACK. What is your expectation for power in the feasibility study?

Mr. JAFFE. We really haven't given that a tremendous amount of thought at this particular time.

Mr. ROBACK. Don't you think you should? If NASA is the far out agency in communications-and it doesn't have very much justification for being near in on communications apparently-why aren't you studying the power source?

Mr. JAFFE. We are studying the power source, but our basic reason for the follow-on series of ATS spacecraft is to develop antenna technology, and as our first step we would like to determine what an optimal approach would be to erecting a large area antenna with suitable characteristics in space, and to see what constraints might be placed on additional things that might be done, power being one of the additional experiments that one might fly.

Mr. ROBACK. The second generation is bringing you into the 1970's. Mr. JAFFE. We hope so.

Mr. ROBACK. And, therefore, you have to know pretty much what vour power supply is going to be. You also want to know whether that big antenna that you want to put up will be interfered with by nuclear power, let us say.

Mr. JAFFE. That is correct. I might just say this about power. It has been our considered judgment that solar cells will be the device used to create power in space through probably mid 1970's. We can go to the several kilowatt level using power supplies made of solar cells involving rather large area structures.

The next generation will probably be the nuclear supply of the SNAP-8 variety, reactor type of power supply and this will not be available until the late 1970's, so that we have given a considerable amount of attention to this, and there seems to be nothing better at this particular time for the kind of power generation capabilities we are talking about, other than solar cells.

Mr. ROBACK. Is it because it is hard to get the budgetary allocation, or is it because you don't think it is timely?

Mr. JAFFE. I think it is the technology limitation. We do not have at this particular time anything which looks substantially better on the forefront than solar cells for this particular power class. Furthermore, there does not seem to be anything on the technical horizon which will preclude the continued use of solar cells in the area of power that we are talking about now, from zero to perhaps several kilowatts.

Mr. ROBACK. Are you experimenting with great masses, great arrays of solar cells?

Mr. JAFFE. We have done a number of studies looking at how one might carry solar cells on large area structures, yes.

Mr. ROBACK. You are really afraid to to deal with this nuclear stuff, afraid you might get burned?

Mr. JAFFE. No, sir; I wouldn't put it that way.

Mr. ROBACK. Afraid it is poisonous?

Mr. JAFFE. Our current rate of progress in the development of the reactor supply indicates that we will not have a reactor supply available to us of the SNAP-8 variety, which we think is a next generation type of power unit, until the end of the 1970's, and our plans, our internal plans are based on that assumption.

Mr. ROBACK. You want to leapfrog the isotope to the power reactor? Mr. JAFFE. We have not found an economically attractive isotope supply at this stage of the game that would be acceptable to all concerned.

Mr. ROBACK. You said you had a feasibility study on the second generation ATS.

Mr. JAFFE. That is right.

Mr. ROBACK. Is that under contract?

Mr. JAFFE. Yes, it is under contract.

Mr. ROBACK. Can you supply us, without too much difficulty, a list of all the contracts now outstanding and about to be let? Let us say the RFP's that have been put out for satellites, communication satellites, a list of the contracts, a brief description of what they propose to do, and the cost estimates, if available, of what the effort is going to cost?

Mr. JAFFE. Yes.

Mr. ROBACK. Just so we get a little idea of your imagination and variety.

Mr. JAFFE. Yes, sir.

(The list referred to follows:)

Summary of current and pending contracts concerning advanced communications technology

1. ITT Contract, "Modulation Techniques for Active Communication Satellites," NAS5-10123, $360K. Study and development of a time division multiplex approach to a multiple access communications satellite system.

2. RAND Contract, "Technological Studies and Operational Factors," NASr 21 (02), $350K. Technical studies of communications satellite systems. Includes theoretical studies of modulation and multiplexing techniques for multiple access; stabilization and control systems for active and passive communications satellites; factors affecting orbital control.

3. SSC Contract NASw-1216, "Studies of Communications Satellite Systems," $98K. Studies of time division multiple access systems applicable to small terminal communications; studies of interference prediction techniques, broadcast satellite subsystem studies.

4. G. E. Co. NASW-1475, $125K; RCA NASw-1476, $125K. "Voice Broadcast Satellite Mission Studies." Two independent studies of short wave and frequency modulation broadcasting of aural program material.

5. Radiation Applications Inc. NAS5-3923, $130K, "Development of a Prototype Plastic Space Erectable Satellite." Develops irradiated polyethylene as a lightweight photolyzable structural material for passive communication satellites.

6. G. T. Schjeldahl Co. NAS5-3943, $135K, "Development of a 425 Foot Diameter Passive Communication Satellite with Self-erecting Properties."

7. AoTech Corp. Contract Pending, $85K, "Millimeter Wave Steerable Antenna Studies and Development." Studies spacecraft beam forming and steering techniques for the range 30 to 100 gcs.

8. B. T. L. "Deep Space Communications and Navigation System Comparison and Tradeoff Study," Contract Pending. Study of advantages of alternative approaches to deep space communications.