« PreviousContinue »
The advantages which we like to state here, that I think are high in the solid area, is the high thrust capability, short development cycle, relatively low development cost, and probably high density of the overall propulsion system and probably the simplicity, which, of course, might be reflected, also, by impressive increase in reliability. We looked over a Boeing study here which states that the introduction of the solids in this particular area could be accomplished by yielding a vehicle which would have 100-percent greater payload capability with a 50-percent reduction in cost taking the example of the Saturn I-B.
One of the things which we like to leave here; this is the necessity for the development of thrust vector control system for these units which presently are, in the overall program, not introduced yet. I would like to also mention in the booster systems that there might be a spin-off of the program in M-1, introducing the units around a plug nozzle and combining it with a recovery system might yield an advantage here. I would like to also mention the introduction of single stage to orbit, you will note in the writeup here would probably be specially realized if we would consider the high-pressure engines. Summarizing here, I would like to just leave the thought that we look at our progressive evaluation of all the chemical propulsion in space with a rather careful balance in which we are taking the research efforts which provide the long-term advances in one consideration, the development where we are capitalizing on the fruits of the previous research and the application is the third one, and to our best integration for available propulsion systems.
Here we also would like to make sure that we are optimizing here within the confines of the available resources.
So that reminds me of the description of a muu-muu, the shapeless dress which somebody said this is identified as a body which maintains a bank account, you know it is in there, but you don't know how much. We believe that with the overall analysis of all these four components, we could probably come up with fairly reasonable recommendations. And these are in the research areas, we would like to recognize the gain of the 30 percent in systems by the utilization of the advanced high-pressure engines, the work centered around the tripropellant system with beryllium and hydrogen and oxygen and storable upper stage where OF, and diborane or hydrogen and fluorine is a very good candidate. In the development areas we would like to just make one point here and this is that the support of the programs without the immediate applications, I think should be encouraged. I would like to point out here we probably wouldn't have a Saturn V vehicle if the work hadn't been done on the F-1 in advance, for example, also we wouldn't have probably today our A-11 fighter if the work on the J-58 engine wouldn't have been encouraged without the recognition that actually at the time the work was done there was application for it. So we believe the M-1 is our example in this particular area. The blending of fluorine with oxygen is another one, and the introduction of the solid 260-inch rocket with introduction of TVC and the man rating of the system as a very important consideration.
In the applications which we would like to encourage everybody around us especially to make sure that the application of the 260-inch solid propellant booster is being considered because the gains which
we already are seeing now, whether this is in the application of the Saturn I-B or of the Saturn V, I think are quite impressive, if we consider the half-length or the full-length boosters in the basement of these particular vehicles.
Mr. Chairman, this is all I have to say on behalf of Aerojet.
During your presentation you made a recommendation, maybe I didn't understand it correctly, but I think I did, you said that insofar as large boosters are concerned we should stay within the state of the art rather than develop the more sophisticated high energy propellant systems. Did you mean this for development, or did you mean it also for research and development?
Dr. KIRCHNER. If I understand your definition of research and development I would say yes, this is actually for the immediate engines for the applications for vehicles. I would stay with the simple chemical systems.
Mr. KARTH. What do you designate as the simple?
Dr. KIRCHNER. I would consider lox-hydrogen as one, I would consider polybutadiene as one. In the storable areas I think N2O, and the amines. But these are systems quite well defined and I think as far as the processes are concerned they are quite reproducible and they are not going to introduce a significant development angle in the large engines.
In addition to that, I think the aspects of costs are, of course, very important because, of course, we are utilizing these materials in millions of pounds.
Mr. KARTH. Wouldn't you include also in that group hydrogenoxygen?
Dr. KIRCHNER. Yes, sir.
Mr. KARTH. How about fluorine-oxygen?
Dr. KIRCHNER. Well, I think if we look at the cost of fluorine, probably presently I would probably not consider it. I would also, because of the large quantities and utilizing this material in the, let's say, immediate stages, I would be probably concerned a little bit about the toxic aspects of the system.
Mr. KARTH. You would also place fluorine-hydrogen in the same position, I assume?
Dr. KIRCHNER. Yes.
Mr. KARTH. How about the diboranes?
Dr. KIRCHNER. As far as the storability of the propellants are concerned I think they are most impressive and I think the work should be encouraged especially in the area of upper stages. I think the payoff, as far as energy release, I think is quite important and I think utilizing it in also small quantities there I think the aspect of cost could be very well accommodated.
Mr. KARTH. So you are recommending that we do considerable research in these areas where more sophisticated propellants are involved, but insofar as the development of large boosters are concerned we should stick with the state-of-the-art propellants, is that what you are saying?
Dr. KIRCHNER. Yes, sir.
Mr. KARTH. On page 4 of your prepared testimony-I have tried to skip through this very rapidly, you say the M-1 program could be accelerated by application of additional support, for instance, if more funding were made available.
Dr. KIRCHNER. Yes, sir.
Mr. KARTH. How much additional support?
Dr. KIRCHNER. Well, I think probably if we could, let's say, double the effort in this particular area, this would be, starting in 1965. Mr. KARTH. Then we would hit the calendar year 1968 date as opposed to the 1971 date, is that right?
Dr. KIRCHNER. Yes, sir.
Mr. KARTH. By doubling the effort this year and maintaining that effort for the next several years?
Dr. KIRCHNER. Yes, sir. I am talking about the fiscal year 1965 actually now.
Mr. KARTH. Now, the M-1, that is hydrogen-oxygen, isn't it?
Mr. KARTH. And you include that as one that is within the state of the art?
Dr. KIRCHNER. Right. As far as fuel systems are concerned, I think they are quite well characterized.
Mr. KARTH. You talk about the longer range improvements in space propulsion by the use of beryllium or aluminum-hydrogen-oxygen combination?
Dr. KIRCHNER. Yes.
Mr. KARTH. I wonder if you could better identify this longer range definition. What do you mean by longer range? What time frame are you thinking about for this propellant system of the future? Dr. KIRCHNER. I think probably I would place it in, as far as the aluminum systems are concerned, I think we are doing quite a lot of work already now on the storable system with nitrogen tetroxide and the amine system. We identify them as gel propellants and I believe in the next 3 years we probably are going to see some fairly good hardware coming through the test area.
Mr. KARTH. There have been some tests already made by the military with these propellants?
Dr. KIRCHNER. That is right, the aluminized system. This is an effort which is still quite limited but it is exploratory, in which we are utilizing the Titan hardware and we are using the tripropellant system for the evaluation now. The problems I think are probably going to center around certain heat transfer programs around the nozzle area, but we believe that this particular effort you can directly translate to the beryllium, where beryllium hydrogen oxygen system, where you have really quite an impressive gain. This would be one of the rather simple chemical systems still, and yet-because you don't have to especially embark on unusual marshaling of industry, and give you a propellant which has a specific impulse of 500 seconds.
Mr. KARTH. I understand with modest modification of our present stable of vehicles, the so-called aluminized gel storable propellants could be used. Is that your understanding of the advancement we have
Dr. KIRCHNER. On aluminum, yes. On beryllium there is very little work done yet. But I think the point being that we are working now on components in Aerojet in the introduction of this, this tripropellant system.
Mr. KARTH. Is it true that with modest modification of our present boosters that we could use the aluminized gel storable propellant?
Dr. KIRCHNER. This is visualized that this would require modest modification; as far as really supporting it by actual evidence we don't have too much of it under our belt.
Mr. KARTH. Would you say it would require greater modification than the flox, for example?
Dr. KIRCHNER. Well, I would feel that it probably might require
Mr. KARTH. But the net result is that the payload again would be substantially more, would it not?
Dr. KIRCHNER. Well, between floxing the engine and aluminum I guess this program might be pretty close to it. Wouldn't you say, John?
Mr. MOISE. That is right. The gain with aluminum in a storable system might be comparable to the gain in floxing a lox-RP system, would not be greater, but some of the other metals, for instance, the aluminum hydride which may come along in the storable systems would provide a substantial gain.
Mr. KARTH. Mr. Bell?
Mr. BELL. I have no questions, Mr. Chairman.
Mr. KARTH. Mr. Wilson?
Mr. WILSON. Dr. Kirchner, in your analysis of using these various propellants that you are describing beyond the current systems, have you made an analysis of the tradeoff in dollars per pound of payload that might be achieved by the near future propellant systems that you have been talking about, both solids and liquids, on such systems as the Saturn V?
Dr. KIRCHNER. We did it on a similar system and in which, as far as the solids are concerned, I think 18 cents a pound breakoff point we recognize on the 10-second impulse; I think the most impressive gains are around a factor of four, which you can do for a third stage and I think this is more or less in relation to the same figures which Mr. Tischler mentioned in his testimony here a few days ago.
Mr. KARTH. I wonder if I could interrupt to ask a question at this point. If we used as much solid propellant as we do with the stateof-the-art liquid propellants today, what would that do in terms of reducing the cost for solids?
Dr. KIRCHNER. As far as the reduction of costs of solids are concerned, I think when you look at the 260-inch engine, I think they already are fairly low. We are talking about something in the neighborhood of one and a half dollars a pound of total hardware, which I think represents already a very low-cost item for space propulsion. So the extension in the additional use I think probably is going to be fairly limited.
Now, I don't know whether I have answered your question, Mr. Chairman, but we already
Mr. KARTH. You say on page 6 of your statement the results of the Boeing study indicate that the 260-inch-diameter launch vehicle, will
launch payloads 100 percent greater than the Saturn I-B at costs of currently planned payload that are 50 percent less. I am not sure what kind of a yardstick Boeing used in determining the cost of the propellant. So my question was that if we used as much solid as we today use liquid which normally should make the propellant cheaper, would it still further reduce that figure, and, if so, how much?
Dr. KIRCHNER. I think we have to compare now the costs, the comparison was made for the Saturn I-B, if I recall correctly and I don't think-I think the gains, it depends when the introduction of the solid would be made as far as then retrieving, let's say, from the funds allocated for the I-B to begin with.
Mr. KARTH. Well, it has always seemed to me that we have spent so little really in the development of solid propellants, and that had we made a little greater effort in this field that we might now be enjoying a substantially lesser cost in the use of solid propellants and as a result of that it might even encourage greater speedup of development of the large solids. Would you agree with that statement?
Dr. KIRCHNER. Yes, sir. I think the point of view is very well, I think, also recognized in the industry and I am pretty sure that Dr. Ritchey would also underwrite it.
Mr. KARTH. Thank you very much, Dr. Kirchner, we appreciate your appearing before the committee.
RESPONSE TO PREPARED QUESTIONS FROM THE SUBCOMMITTEE ON NASA OVERSIGHT COMMITTEE ON SCIENCE AND ASTRONAUTICS OF THE HOUSE OF REPRESENTATIVES
(By Dr. Werner R. Kirchner)
Question. Aerojet: "What are your latest ideas in the area of advanced propulsion? What are the chief advantages of a staged combustion engine over more conventional engines? Have you ever experienced combustion instability in a stage combustion engine? If not, isn't this an immediate tremendous advantage over our present engines? Shouldn't it reduce blow-ups and generally shorten engine development time? Are there advantages this system has over the present Saturn and M-1 engine system?"
Answer. Aerojet's latest ideas in the area of advanced propulsion for boosters involve the use of high chamber pressure and a staged combustion engine cycle. High chamber pressure provides higher engine specific impulse by permitting a higher expansion ratio nozzle to be used. The staged combustion cycle, with the turbines in series with the combustion chamber, eliminates energy losses normally required to drive the turbine. These two effects can result in specific impulse gains of about 20 seconds relative to conventional engines. Our advanced technology work with liquid oxygen/liquid hydrogen for NASA, and with storable propellants for the Air Force has produced encouraging results both with respect to staged combustion cycles and high-pressure operation. Initial results indicate that combustion instability may be eliminated by stage combustion; however, it should be pointed out that a great deal more testing must be accomplished before conclusive results can be assured in an area as complex as combustion instability. If these results continue to be encouraging as we anticipate, the absence of serious stability problems which has also characterized current liquid oxygen/liquid hydrogen engines, such as the RL-10 and J-2, should continue when the more advanced systems are developed. There are some indications that combustion of gaseous rather than liquid propellant such as occurs in regeneratively cooled liquid oxygen/liquid hydrogen engines minimizes stability problems. It is extremely important to carry on the highpressure advanced technology work at an increased level of support for the next few years so that a firm engineering basis will be provided for incorporation of these modifications for future improvements into such engines as the M-1. Question. Aerojet: "Do you foresee any major technical problem areas in your advanced engine configuration which have yet to be solved? If so, what are they? Have you been given any NASA funds to tackle these problems? How