and disassembly building will take about 4 years from its inception to operational capability.

The second problem in connection with facilities is also related to the engine design. This concerns the art of operating the equipment and engine from remote positions due to the radiation hazard. We, of course, have learned much from LASL's test operations on test cells A and C and their maintenance assembly and disassembly building. However, we will be working with additional new devices such as turbopumps, valves, and instruments which have been designed for the first time for remote handling and disassembly. Suffice to say that when we are operating this equipment at optimum efficiency, we will indeed have improved the state of the art in this

area.

As I have mentioned at the outset, vehicle technology or state of the art is part of a final nuclear rocket propulsion system. I also touched on this point in the turbopump assembly discussion. The problem arises from the radiation effects on the hydrogen propellant in the vehicle tank. The hydrogen is heated by the radiation and sets up convection currents in the tank and these in turn affect the propellant outlet conditions at the bottom of the tank where the propellant flows to the engine. This heat in the propellant, and possible bubble formation, seriously affect pump suction characteristics. It is not possible to analyze this system completely or to stimulate it by any other means than true nuclear radiation. Development of the flight tank flow baffle system is required and testing must be conducted with the complete system before it may be concluded that the flight engine is indeed ready for use. I mention this to point out that in nuclear rocket flight propulsion development, it is desirable to carry out the program with some degree of concurrency. Otherwise, if done on a sequential basis, a very long time will be required. Indeed, effort may well be expended on problems that are not real in the actual flight systems and other real problems will not be uncovered until a very late date.

In closing, I would like to summarize our statement in the following way:

Propulsion development has traditionally paced our major steps forward in flight. We are at the threshold of proving the feasibility of a new and far more efficient means of space propulsion. We believe the major problems areas have been identified and are near certain solution. This is particularly so in the nonnuclear areas, and in the nuclear areas our tests to date, as you have heard, are extremely encouraging. Because of this status of development we sincerely urge that you encourage NASA to work with undivided attention to complete the feasibility work and be prepared to assist in relaxing the constraints with regard to vehicle and facility programs so that our space effort may capitalize on this imminent breakthrough.

Thank you, gentlemen.

Mr. TEAGUE. Any questions of Mr. House?

Mr. BELL. Mr. Chairman.

Mr. TEAGUE. Mr. Bell.

Mr. BELL. Mr. House, do you feel that this reactor has pretty well worked out its bugs? In other words, as I believe you mentioned, and has been mentioned previously, you had some trouble with the graphite

Mr. HOUSE. That is correct.

Mr. BELL. That was caused primarily by many things, but I assume one of the results of it was that had a tendency to break up a little bit: isn't that correct?

Mr. HOUSE. Yes. There was vibration and we are pretty sure now that this was caused by the flow of hydrogen through the core in the cold conditions, which caused the fuel elements to shake or vibrate, and thus break up.

As I have said in my prepared statement, we in industry and LASL have had two cold flow tests since that date and these have shown that there is no vibration present in the redesigned core.

Mr. BELL. In other words, it is the vibration rather than the cold use of the propellant that has caused this to break up, in your opinion? Mr. HOUSE. That is right. This was a mechanical problem rather than a nuclear problem, and we feel that we understand this type of thing.

Mr. BELL. What kind of proof do you have that you think this has been solved, the breakup of this reactor?

Mr. HOUSE. Well, the proof centers around the fact that neither the LASL reactor nor the Westinghouse reactor, which went through tests last month and this month, had any breakage in the fuel elements. Mr. BELL. And they went through the same type of test?

Mr. HOUSE. Right.

Mr. BELL. I see.

How about the vehicle work, is that proceeding along as expected, or have you called a halt on that?

Mr. HOUSE. Well, I think you may be aware that in December or January, I am not sure of the exact date, that the RIFT1 program at Lockheed was canceled so that we do not now have this parallel vehicle program going along with the engine development.

Mr. BELL. Why was that canceled, do you know?

Mr. HOUSE. I am not certain of that, sir.

Mr. BELL. Was it lack of funds, or something?
Mr. HOUSE. That is my understanding.

Mr. BELL. That is all, Mr. Chairman.

Mr. TEAGUE. Mr. Daddario.

Mr. DADDARIO. Mr. Chairman.

Mr. House, how do you use the word "sequential," on page 7, where you say, "If done on a sequential basis"? Do you mean in proper sequence? Are you talking about the sustained level of financing which keeps the thing going sort of up and down?

Mr. HOUSE. No, I am talking about the sequence of developments here. In other words, if we look at a bar chart in time, and we say we are developing the engine here and we come to the end of the engine development, I am saying that we want the vehicle program to start somewhere before the engine has been completely developed. Then the interface problems between the two systems can be worked out. Otherwise, if you wait until the engine is completed, and then start the combined testing of engine and vehicle you will discover new integration and interface compatibility problems. Perhaps you will also

1 RIFT-reactor in flight test-the vehicle stage for the flight test of the NERVA engine.

find that you have solved some problems that you really didn't need t solve in the engine development tests alone.

Mr. DADDARIO. You then need sustained financing to do that, so tha you won't have your program thrown out of whack?

Mr. HOUSE. That is correct.

Mr. DADDARIO. What is there in the program at the moment which would indicate that it is not being done on the basis that you believe to be necessary?

Mr. HOUSE. Well, as I indicated, the budget restraints essentially put the RIFT program out of being at this time.

Mr. DADDARIO. Then in the last paragraph where you talk about "be prepared to assist in relaxing the constraints with regard to vehicle and facility programs," what do you mean by that, are you going on a psychological aspect?

Mr. HOUSE. No, I am referring again to the RIFT situation. That program was canceled. As I indicated in my prepared summary, the long leadtime for the test facilities required to do these development jobs is going to be the item pacing the overall development unless action is taken to design and start construction of these very long leadtime facilities. And this is particularly true for the vehicle and engine development test area at NRDS.

Mr. DADDARIO. Then in that, so that it is clear, you are talking in support of a proper level of financing to do this, and you are not including in this last part involving constraints, though, psychological problems which involve the construction of the facilities necessary to do this work or disposal of the nuclear products, that type of thing? Mr. HOUSE. No, sir.

Mr. DADDARIO. Thank you, Mr. Chairman.

Mr. TEAGUE. Mr. Fulton.

Mr. FULTON of Pennsylvania. We are glad to have you here.

You have spoken of the vehicle and facility program canceled, the RIFT program; how much longer will it take to get a successful operational vehicle if that cancellation remains?

Mr. HOUSE. Sir, I am afraid I cannot honestly answer that, because it is a question of when the program is reinitiated. I have no knowledge of when that will be. Consequently, it is at least a day-for-daytype thing.

Mr. FULTON of Pennsylvania. But if we do these things concurrently, which we could, we would save quite a bit of time because there is a long leadtime on both vehicle and facility programs; isn't there? Mr. HOUSE. That is correct.

Mr. FULTON of Pennsylvania. How long a leadtime would you say that was?

Mr. HOUSE. Well, I estimate on the average that, on the basis of experience to date, a test facility will take about 3 years. So from the date you decide you are going to build a facility, it will be at least, 3 years before you can conduct a useful test in that facility.

Mr. FULTON of Pennsylvania. You have stated that there is an eminent breakthrough in this program, which is a very successful result; is that not right?

Mr. HOUSE. That is correct. We feel that by obtaining the specific impulse available to us with the nuclear rocket, there will be a definite breakthrough in space propulsion and in our ability to perform space

Mr. FULTON of Pennsylvania. You would therefore recommend that this committee do not decrease the budget or recommend a decrease in budget authorization for the NERVA program at this time? Mr. HOUSE. That is correct.

Mr. FULTON of Pennsylvania. What effect would it have if we did take a part of the money away after it has been cut, I believe, to $58 million for the current fiscal year?

Mr. HOUSE. Sir, it will just add that much more time. I can't, of course, account exactly for what those dollars will do in stretch out of the program, but it simply means a longer time before we will have an operational nuclear rocket and the development will cost more in the long run.

Mr. FULTON of Pennsylvania. With every evidence of success, because of the experiments that you people have, and the Westinghouse Astronuclear Laboratory have been performing, you do feel it is worth while that emphasis be placed on this NERVA program by the Subcommittee on Legislative Oversight?

Mr. HOUSE. Yes, I do.

Mr. FULTON of Pennsylvania. Thank you very much.

Mr. TEAGUE. Mr. Downing.

Mr. DOWNING. Tell me briefly, what are the tremendous advantages of this form of propulsion over the other types we have?

Mr. HOUSE. It relates to the specific impulse that one can obtain from the nuclear rocket, of course. In the lunar missions our preliminary studies indicate that 50 to 70 percent greater payloads can be achieved as an upper stage on the SATURN V launch vehicle. If you consider the interplanetary missions, depending on the specific year and time of year of flight, this improvement can be from two to five times the payload capability of the equivalent weight chemical system.

Mr. DOWNING. With nuclear propulsion would you have a continuous source of power that you could use at any time or would that power be exhausted, only taking a longer time than the present fuel system?

Mr. HOUSE. This is directly related to the specific impulse of the rocket and to its restart capability. The fact that we have approximately twice the performance of the best chemical system means in effect for the same thrust you can operate it twice as long. Also it is an inherent characteristic of the nuclear rocket that you can restart and refill the vehicle with propellant in space, if you elect to, and continue to operate the engine.

Mr. DOWNING. That is my point. Do you mean you could have continuous operation in space with nuclear rockets?

Mr. HOUSE. There is no limit at the moment, as we see it, on the duration. It is a question of tankage on the vehicle.

Mr. DOWNING. I don't believe I understand tankage.

Mr. HOUSE. Well, it is a question of how much propellant you can carry on the vehicle at any given time on any given mission. Without the ability to refill the vehicle tankage with propellant we are perhaps talking about the order of hours' duration.

Mr. DOWNING. I confuse it maybe with the Enterprise, which is nuclear propelled. Now, that can go for 3 years without any replacing of the cores, but that principle doesn't apply here, does it?

Insofar as the propellant supply, no, because we cannot launch tha amount of propellant with any current booster system. However, i we could assemble a large number of propellant tanks in orbit or on single very large tank we will have a much longer operational capa bility.

Mr. DOWNING. Would the same thing hold true with any other propellant?

Mr. BELL. Will the gentleman yield?

Mr. DOWNING. Yes.

Mr. BELL. I think perhaps maybe an explanation may be in order As I understand this, is this not correct, you have your reactor core and then you run your propellant through the reactor core which gives the amount of heat which makes the vehicle go. So you do have to have a certain amount of propellant to run through the core which gives your heat energy. Is that explanation a help to you? Mr. DOWNING. In other words, you have got to carry some

Source

Mr. BELL. Some source of propellant. But the point is, you have to carry a much lesser amount of propellant than you would with a chemical rocket. The reactor can carry you much farther into space with less propellant than a chemical rocket, but you do have to run some propellant through the core itself.

Mr. DOWNING. Thank you very much.

Mr. FULTON of Pennsylvania. Would the gentleman yield?
Mr. DOWNING. Yes, indeed.

Mr. FULTON of Pennsylvania. If we kept one of these nuclear reactor engines operating as an upper stage in space, possibly on a lunar-earth orbit, never bringing it down, we could do a rendezvous procedure, providing the propellant, because the reactor is good, as you have said on the Enterprise for 3 years. So that under those circumstances there might be a very long life to this particular vehicle which could be reused for other missions.

Mr. BELL. Will the gentleman yield? Would you yield on another point, Mr. Downing?

Also there is another aspect of this, that is of interest, I think. The fact that you are getting more toward the transportation area because actually, isn't it true, with a nuclear rocket as a second stage, you would not have to have so many stages?

Mr. HOUSE. That is correct.

Mr. BELL. In other words, you wouldn't have to have so much artillery that you would have to throw away. So it is actually an economy in that area, too.

Mr. DOWNING. My point is, if you could take conventional propellant and put enough of it up in space you could do the same thing, maybe not as well, but you could accomplish the same thing.

Mr. BELL. I didn't get the first part.

Mr. DOWNING. With the conventional propellant, chemical.

Mr. BELL. No, you couldn't accomplish the same thing, because you don't have the ability to go the distance with the size of the rocket itself. In other words, you don't need so much propellant to go to the Moon or to Mars. Whereas, with a chemical you need more propellant, you would have to have more tankage and more of them.