OTA's Final Report on "Big Dumb Boosters"

Although I was forewarned² that MCD was unacceptable to the aerospace community^A, I could not resist sending them the 9-page commentary on the draft report mentioned in the previous Column. I guess I could not restrain myself from taking the opportunity to clarify the MCD criteria; I have always hoped that attitudes might have changed in the interim. As I mentioned previously, none of my counter-arguments was incorporated in the final report.

I have chosen to express my views and counter-arguments to OTA's final report by reviewing it section by section. Most sections cannot be summarized easily; besides, I do not want to possibly misinterpret or misrepresent statements made. I am forced, therefore, to beg the reader to download the report^1,B. The page numbers and paragraph titles refer to the final report.

Page 2. Origins of Today's Launch Vehicles

As I explained in a preceding Column³, to the best of my knowledge everyone, including myself, who worked on the early ballistic missiles and space launch vehicles, accepted without question the applicability of the minimum weight/maximum performance criteria. Although cost was not a prime consideration at the time, it was understood by most designers that using the customary aircraft design criteria would result in minimum cost systems. Except for the singular case when the weight of the vehicle was limited by a transportation constraint, the "stringent performance specifications" could have been met by the MCD criteria. Unfortunately we had no inkling of it at the time.

I have seen no analytical evidence to support the statement that the Shuttle's recurring cost would have been less if no limitations were placed on its development cost. Moreover I too believe that the Shuttle was "sold" on imaginative, exceedingly low estimates of recurring costs, as a technological challenge requiring a large program effort, and as a program that would place men in space which would have public appeal and support.

Page 3. A New Design Criterion

Actually the development of the MCD/LSV (or the Big Dumb Booster) was canceled one week after the local Air Force presented the first briefing to industry on the program⁴. Industry realized that the MCD criteria was being seriously considered by the Air Force and obviously did something about it - fast. True, the Shuttle program blocked the further development of a "real low-cost robotic launch system⁵," but this policy was formally established by the White House six years later, in 1972.

Page 4. Continued Controversy

OTA described MCD as a "philosophy" which it is not. It is a design criteria based upon physical facts and mathematical analysis. The Big Dumb Booster was an analytically- derived application of the criteria and was not a "concept." A concept implies an "idea." Other designers, employing the MCD criteria, would probably have derived different configurations that might have been slightly better or slightly worse. The designs would change with time with advancements in materials, fabrication processes, etc.

True, there was overwhelming evidence that the Soviets did not design to a minimum cost criteria. However, I learned from people whose job it was to know that the Soviets saved considerable amounts of time and money by not striving for the ultimate in weight savings. By stressing design simplicity, which incurred only minor weight penalties, they also compensated for a shortage of appropriately trained engineers and shop personnel, and for limited sophisticated fabrication processes, limited materials availability, and other limited resources.

Page 5. Payloads

The arguments OTA presented against applying the MCD criteria to payload design, which would permit lower cost and less weight-constrained payloads, were clearly naive. The arguments were made by a workshop participant who claimed that payload designers probably would not take advantage of the opportunities the MCD criteria would provide. To counter this possibility OTA felt that adherence to the MCD criteria would require "considerable management discipline," an observation that I fully agreed with.

I was pleased to see that OTA agreed with the design decisions that the Big Dumb Booster provide only a standard payload interface, thus eliminating mission-special interfaces, and not provide such services to the payload as power and air-conditioning prior to launch. The same design decisions were made in the Advanced Launch Vehicle (ALS) program which were probably supported by extensive cost analyses.

Page 6. Conclusions

It should be noted that OTA made no "assessment" or evaluation of the MCD criteria and the Big Dumb Booster, nor explain their potentials. However, OTA appeared to accept the rationale of the MCD criteria as applied to space launch vehicles. By limiting their effort to reporting only the positive and negative arguments presented at the workshop, it appears that Congress was not interested in OTA's assessment of the MCD criteria or the Big Dumb Booster.

I was pleased by OTA's suggestion that Congress fund either the Air Force or NASA to conduct a thorough systems study that would include "launch facilities, logistics and support" although I felt that the likelihood of this ever happening was negligible. I based this view on the abrupt cancellation of the Air Force development program for an MCD/SLV in 1968⁶ soon after it was officially started. I believed that the same, negative forces that existed then existed in 1989, the time OTA prepared their report. Congress did not fund the Air Force or NASA to conduct the in-depth study OTA suggested.

Page 7. Alternative Approaches

To the best of my knowledge, Congress also did not fund any of the alternate studies suggested by OTA. These studies are identified and commented upon as follows:

• Fund NASA to apply the MCD criteria to the Liquid Rocket Booster Study current at the time.
• Task the Air Force and NASA, who are designing a minimum cost space launch vehicle system under the ALS program, to also design a vehicle that resembles the Big Dumb Booster. (I did not view this as a valid suggestion because I felt that a design team should be permitted to derive their own design as long as it is based upon a rigorous minimum cost design analysis. It appears that the ALS program did design to the MCD criteria⁶.)
• Fund the Air Force and NASA to investigate technologies related to the Big Dumb Booster; such as, the gas pressurization system of a pressure-fed propulsion system, and high-thrust, low-pressure engines. OTA noted that one of these recommendations was already underway under the Shuttle LRB program.
• Fund an industry competition between an SLV designed in accordance with the MCD criteria and one designed for minimum weight/maximum performance.
• Do not hamper the development of commercial, minimum cost SLV's, particularly by startup companies. (I saw no evidence of congressional involvement in startup companies striving to design minimum cost launch vehicles.)
• Assume that the Air Force and NASA will make the correct design decisions since they are under pressure to reduce launch costs. (It seems that the Air Force more than NASA has been making progress toward this end by downplaying the minimum weight/maximum performance criteria.)

With the writing of these Columns, I have sought to present a comprehensive understanding of the MCD criteria⁷. I have defined and rationalized the criteria, illustrated its use by describing several applications⁸, noted particularly recent instances where it has been accepted and applied⁹, and spotlighted the critical institutions that have been keeping it at bay as I have personally experienced¹⁰. I hope this critique of the OTA report has added to the understanding of the various aspects of the subject. 

References

1. "BIG DUMB BOOSTERS A Low-Cost Space Transportation Option? An OTA Background Paper," February 1989. (Available for reading/downloading via the OTA Publications Web Page (select year = 1989), or, more directly at http://www.wws.princeton.edu/%7Eota/disk1/1989/8904.html.)
2. Column dated October 10, 1997.
3. Column dated March 15, 1997.
4. Column dated May 15, 1997.
5. Los Angeles Times, October 2, 1988, p 18-19, quoting Thomas O. Paine, NASA administrator (1968-9).
6. Column dated November 10, 1997.
7. Columns dated February 15, March 4 & 15, and May 15, 1997.
8. Columns dated April 10, and May 1 &15, 1997.
9. Columns dated May 29 and June 26, 1997.
10. Columns dated September 18, October 10 and November 10, 1997.

Notes

1. Namely; Congress, the procurement agencies (primarily the Air Force and NASA), and the aerospace industry.
2. All OTA reports can be downloaded free of charge. They are as PDF files and are read by Adobe Acrobat Reader. 

What questions has the OTA report and the critique raised in your mind? [clicking on the above opens link to discussions that followed the initial posting of this column]

Next Column: Discussion of remainder of OTA's final report, "Big Dumb Boosters."

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