SSTO: A Path to Minimum Cost?

This column will revolve about a central issue. As far back as 1959, while employed by Space Technology Laboratories (split in 1961 to form The Aerospace Corporation and the TRW Systems Group) I was astonished to discover that ballistic missiles, space launch vehicles and payloads (satellites) have been and are being incorrectly designed to airplane design criteria that calls for the minimization of weight and maximization of performance. The criteria is ingrained in all aeronautical engineers, and its use results in minimizing the cost of most winged aircraft. At that time, I introduced a more appropriate criteria for the design of space systems that I called design for minimum cost, or, minimum cost design (MCD). I crudely showed that the application of the new criteria has the potential for appreciably reducing the costs of space operations.

Intermittently from 1963 to 1968 the MCD criteria, under Air Force, NASA, and contractor sponsorship, was studied by applying it to a large number of system and subsystem designs. It was also used to fabricate and test critical space hardware components. This work was performed mainly in support of two systems configured at Aerospace: the semi-mobile intercontinental ballistic missile (SMICBM, 1963) and the MCD space launch vehicle (MCD/SLV, 1965). Most of the work supported the contention that the use of the MCD criteria could reduce costs by factors ranging as high as 10 or more.

In May 1968, the Air Force program office, established to research and develop the MCD/SLV, was closed down, and all new work relative to the use of the criteria was abruptly halted. To this day the industry, the Air Force, NASA, the Congress, and the White House (sometimes referred to as the aerospace community) refuse to recognize and accept the MCD criteria.

During the interim the aerospace community has worked on many new "low-cost" space launch vehicle programs, repeated studies of some of the same concepts, passed billions of taxpayer's dollars among themselves, and has come up with no firm solution. While this has been going on, the French, Russians, and Chinese have been forging ahead, developing their own SLVs. Their lower cost vehicles (that is, lower than ours) now launch most of the world's payloads including U.S. commercial satellites. By the end of the century and into the next century, with the introduction of the Japanese SLV and the Ukrainian rocket, these countries appear destined to increase their market share.

Currently, there are two, new low-cost launch vehicle programs under study, one sponsored by the Air Force, the other by NASA. Both are worthy of a little scrutiny to see whether our principal procurement agencies are treating a serious national problem in a timely and judicious manner.

The Air Force program is called the evolved expendable launch vehicle (EELV). The program uses updated components of current vehicles and some advancements in technology. Cost savings of up to 50% are projected. The heavier-lift Atlas, Delta, and Titan vehicles are to be replaced by a new family of SLVs that will have low-earth orbit payload capabilities of 2,500 to 45,000 pounds. Nonrecurring costs are estimated at $1.4 to $3 billion. Initial operational dates are 2001 and 2002 for the medium-lift version, and 2005 and 2006 for the heavy-lift version. Operational dates are years later when the vehicles demonstrate reliable operations. If the program isn't canceled and if its modest cost-reduction objectives are met, it seems that the EELVs will be years late and, consequently, may not capture much of the world's market.

There are two developments which may occur under the EELV program that are worth noting. Rocketdyne, as part of the McDonnell Douglas's effort, may develop a liquid hydrogen/oxygen, high-thrust engine that contains 93% fewer parts than the comparable main Shuttle engine. Aerojet and Pratt & Whitney are evaluating and testing engines based on Russian technology (known for their simplicity and ruggedness) for use on Lockheed Martin's proposed EELVs and Atlas IIAR, and on McDonnell Douglas's Delta 3 SLV. I would like to think that some of the guidelines which may have been derived from the MCD criteria have influenced these efforts. Moreover, I was aghast in reading in AvWeek, February 5, 1996, p.86, "But Orbital's [Orbital Sciences Corp.] apparent desire to redesign the X-34 [essentially a test vehicle for the X-33 (see below)] to cost rather than capability has again put the project in jeopardy."

The concept NASA is sponsoring has been studied in depth several times in the past. It is another crack at the life-long dream (the original concept of the Shuttle) of a recoverable, single-stage, winged vehicle that would operate like an airliner, and mimic its relatively low operational cost and turnaround time. It is hoped that further advancements in technology will permit a reduction in payload launch costs to about $1,000/pound, a factor of 7 to 10 less than current Shuttle costs. Estimated research and development (nonrecurring) costs vary widely from $2 billion to $15 billion. I have yet to see a published initial operational date for the vehicle, nor can I find a projected estimate of the cost of each vehicle. With the X-33, the half-scale experimental vehicle first to fly in 1999, I can only assume that the initial operational date is so far away that it can be disregarded as a competitive vehicle in the first decade of the 21st century.

I find the pursuit of the above single-stage-to-orbit (SSTO) most perplexing. Why do some aeronautical engineers persist in believing that the best space configurations should look like airplanes? As I hope to show the reader in later columns, the MCD criteria, applied to this type of vehicle, not only calls for minimum weight/maximum performance design, it also calls for large expenditures in R&D to further minimize weight, maximize performance to achieve lower overall costs. Simple physics and simple cost analyses would show that the addition of a nonrecoverable first stage would reduce costs and development time and bypass the described design and cost dilemma. But this configuration would be reverting to the Shuttle configuration, probably a step at a time, further digressing from the dream of airline operation of a single stage.

I can only come to this conclusion: the SSTO program is meant to provide employment for the more highly-trained engineers and scientists, to advance the design of high temperature structures, and to develop a linear, plug-nozzle, rocket engine. Just about everyone has been lead to believe that advancing technology is great without questioning whether their application appears promising.

Are these programs the last attempt of the establishment to stave off the acceptance of the MCD criteria and the MCD/SLV type of vehicle? Are they worried that it will cause widespread unemployment in the aerospace industry and that some work will be done by commercial industries? Have they performed an analysis to substantiate these fears? Have they performed an analysis that might show the enormous expansion of space activities if launch costs and payloads (also designed to the DMC criteria) costs are appreciably reduced? Others apparently have. Quoting from the Commentary in the January 1997 issue of AEROSPACE AMERICA, prepared by the cochairs of the Third AIAA International Space Cooperation Workshop: "Immediate reductions by at least a factor of 10 are needed if a significant expansion of space activity is to be realized."
 

Will SSTO rocket development lead to lower cost space operations? What do you think? [clicking on "you" opens link to discussions that followed the initial posting of this column]

Next Column: A discussion of the existing, available reports on the MCD criteria, and what these columns will cover in an effort to fill in the gaps and provide an understanding of the basic principles.

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