May 15, 1997

Design Example: The MCD/SLV Continued

There was another reason for providing only a cursory description of the MCD/SLV design in the previous Column, and omitting discussions of many of the subsystems. A more comprehensive description did not seem warranted because the design was developed more than thirty years ago and much of it is considered obsolete. I am sure, by incorporating aerospace and commercial technology advancements, superior minimum cost vehicles can be designed today.

An example of new technology that may drastically reduce the size, cost, and weight of the MCD/SLV was suggested by a NASA representative at the "Workshop on Low Cost, Low Technology Space Transportation Options." (The workshop was held in 1987 and was sponsored by the Office of Technology Assessment (OTA), the technical arm of Congress.) He suggested changing the main structural material from moderately high-strength steel to filament wound S-Glass/Epoxy. I know of no follow-up work on his suggestion. Perhaps better choices of materials exist today. (I plan to discuss OTA's activities in connection with the MCD criteria and the MCD/SLV in one or more future Columns.)

In mid-1965, as the design of the MCD/SLV was coming together, the work in progress was briefed informally to the Air Force and industry. The local Air Force, the Space and Missile Systems Organization, supported by Aerospace under contract, were quite enthusiastic about the work as well as several industry companies, namely TRW and Boeing. NASA initially showed curiosity and later made a formal effort to learn more about the activity by contracting TRW to do an MCD study. Most of the remainder of industry offered or provided little support, and a few were outwardly hostile.

MCD and its potential for reducing the cost of space operations became a popular subject of papers and after-dinner speeches delivered by Air Force colonels and general officers. TRW and Boeing studied the derivation of the MCD criteria and the methods of design analysis. They also studied, fabricated, and tested the engine and propellant tanks. A small stage was fabricated for display purposes.
 
 

  • TRW, using in-house funds, built and successfully test-fired an engine rated at 250,000 pounds of thrust at their San Juan Capistrano rocket test facility. The engine was throttled to 50,000 pounds to stay within the structural limits of the test facility. It was checked for combustion instability, the big bugaboo in liquid rocket engine development. C*, the symbol for combustion efficiency, was measured at 95%. The test also demonstrated a factor of 50 in the scalability of the LEMDE injector, corresponding to a thrust range from 1,000 to 50,000 pounds. TRW estimated the cost of the program at $60,000, an uncommonly low figure for an aerospace program of this content.


    • There was an amusing but instructive side to this program. TRW farmed-out the fabrication of the engine and its supporting structure, less the injector that they fabricated themselves, to a "job-shop," commercial steel fabricator located near their facility. The contract price was $8,000. Two TRW executives visited the facility to observe the fabrication process. They found only one individual working on the hardware, and when queried, he did not know nor care that he was building an aerospace rocket engine. This encounter was told and retold to emphasize the vast dissimilarity with typical aerospace attitudes and procedures.
     
     

  • TRW later received an Air Force contract to provide an engine for test at its rated thrust of 250,000 pounds. The test was successfully conducted at their rocket test facilities at Edwards AFB.


    • I had arrived late to witness the test, and only saw the firing. I was told by others who witnessed the entire test procedure that the engine was pulled out of outdoor storage where it lay unprotected against the elements. Before it was placed on the launch stand, the test crew dusted off the desert sand that had clung to it. This unplanned inclusion of a bit of an environmental test also demonstrated hardware ruggedness of the kind no other liquid rocket engine could approach.
     
     

  • Boeing most thoroughly reviewed the analytical work that led to the MCD criteria and the minimum cost methods of design analysis. They showed intense interest and agreement, and presented the work in a briefing to their management. It was given the (Boeing) name of "SCOT," for "System/Subsystem Cost Optimization Technique." Subsequently, they engaged in an extensive and significant role: they showed that propellant tanks and a stage can be produced at very low cost. The costs incurred by this effort were borne by Boeing.


    • In checking practice against theory, the initial step taken by Boeing was to have a commercial tank manufacturer (Dixie Steel) build a propellant tank of HY-140, the prescribed material, to tighter than commercial tolerances. The tank cost was on the order of several dollars per pound. Boeing production engineers witnessed the entire fabrication process, and made note of the tooling and fabrication techniques used. When the engineers returned to home base they designed their own tooling and fabricated the same tank for less money. To Boeing and all who knew of this sequence of events, the estimated cost and feasibility of the MCD/SLV gained much credibility. The tests demonstrated that even in small quantity, production costs could be quite low.

    Following this, Boeing fabricated a stage of the unrecoverable configuration, sized for the 250,000 pound thrust TRW engine. The last time I saw the stage was at TRW's San Juan Capistrano test facility--more about this later.
     
     

  • Sometime in 1968, NASA awarded a study contract to TRW to design an MCD/SLV, including the design of all major subsystems; such as, the gas pressurization system, the thrust vector control system, the guidance system, and the launch facility including operations. The scuttlebutt was that NASA issued the contract to learn what the Air Force was up to and what the MCD criteria is about. My work as a consultant to NASA on DMC seemed to have made no lasting impression.


    • Early in 1968, the Air Force started to gear up to form an office to research and develop the MCD/SLV. I was completing the paper, "Proposed Minimum Cost Space Launch Vehicle System," when I became aware of political forces coming into play. My supervisor told me of Aerospace's hesitancy in releasing the report, and that I should make Col Floyd Kniss, the Air Force head of the MCD/SLV program, a co-author; this would permit the Air Force to release the report in case Aerospace failed to do so. Recalling my past experiences with the political/economic forces that arose when the customary way of doing business appeared threatened, I gladly added his name. It saved the paper but it did not save the program.

    The Bidder's Conference to kick-off the R&D program was held in the auditorium at Aerospace on 24 May 1968. All of the usual aerospace contractors were invited. In addition, upon the suggestion of Col Kniss, I added several commercial fabricators to the invitation list who might, in this instance, become members of the aerospace industry. They were those who had assisted me with my work by supplying information and data; such as, American Bridge and Iron (a US Steel subsidiary) and Pittsburgh Des Moines Steel. The invitee list was made available to all attendees as part of the handout. I overheard several negative comments by representatives of aerospace companies about commercial companies attending the briefing.

    The handout stressed the fact that the two cognizant offices at Air Force Headquarters in Washington had not yet given their approval of the program. It also asked the recipients of the handout, which contained a preliminary work statement, not to divulge its contents to outsiders, particularly the press.

    I found the handout, which I did not see previous to the briefing, quite disturbing. My biggest disappointment came when I heard Col Kniss start the briefing by saying: "Gentlemen, the gravy train is over!" It produced a huge moan from the audience, then mutterings and a shuffling of bodies. From my past experiences with MCD, I feared the collective power of the industry. At that moment I felt that all may be lost. My intent was to further the industry, not to diminish it. No one saw it that way. Unfortunately, very few see it that way even today.

    About one week later, the program office was shut down. Col Kniss was given an immediate assignment in Paris, and I was banished to "Siberia" (from my perspective) within Aerospace. In fact, I was instructed to sever all communication on the subject of MCD with anyone within Aerospace, in the industry, and in any governmental agency. I was cut-off from the MCD studies that were currently underway and those that were planned to be conducted during the following several years. I was also told that after these studies run their course, MCD and the MCD/SLV will become mute subjects.

    After the shutdown, one significant follow-on study was conducted by Aerospace, and many others were performed under Air Force contract or by industry using in-house funds. I plan to comment on these studies, relying upon information obtainable from the open literature. Also, I plan to report on the results of MCD studies of hardware elements other than the MCD/SLV; these studies were conducted during 1966, 1967, and part of 1968. I further plan to describe my experience in attempting to design an MCD payload and of TRW's successful effort.
     
    Can anyone pinpoint the institution that killed MCD and the MCD/SLV? Should it be revived in the light of the large number of US commercial satellite programs and foreign competition in launch vehicles?

    [clicking on the above opens link to discussions that followed the initial posting of this column]
     

    		 Arthur Schnitt

    Next Column: Additional studies of the application of the MCD criteria

    Return to Published Columns