THE X-15 PROGRAM IN RETROSPECT

Other Contributions





One of the important general claims of the original prospectus for the program was that it would stimulate aerospace research and development. A measure of how well this claim was realized is seen in the following tabulation of technical documents:

Principal Technical Documents Associated with the X-15 Program
Development of X-15 system and supporting R and D276 documents
Flight test results290 documents
General research inspired by X-15 program200 documents
Total766 documents


The total production of over 700 technical documents is equivalent to the output of a typical 4000-man federal research center for a period of some 2 years. Of special interest and significance are the 200 papers reporting general research inspired by the X-15. These latter papers were identified by personal knowledge of various members of the X-15 team and by contacts with-the authors. They are reports of research that would not have been undertaken had it not been for the inspiration provided in one way or another by the X-15. Thus we see statistical confirmation of the massive stimulus and the focus provided by the program.

It is most important to note that this displtty of new technology represents, in addition to specific research results, the acquisition of new manned aerospace flight "know how" by many teams in government and industry. They had to learn to work together, face up to unprecedented problems, develop solutions, and make this first manned aerospace project work. These team were an important national asset in the ensuing space program.

At the start of the Mercury program there was, of course, a significant foundation of missile technology that was heavily utilized for launch propulsion, blunt-body aerodynamics, and heat protection. However, the innumerable added constraints and requirements of a manned aerospace system were present and in this area the X-15 team and the X-15 developments were the principal technology sources. The later developments of the USAF X-20 Dyna-Soar Program, particularly the large advances it provided in radiation-cooled structures and materials, also became available for post-Mercury systems.

If one takes a broad look at all of the contributions of the program and considers relative values based on the actual applications that have been made of the results, it is quite clear that the space-oriented results have been of greater value than the hypersonic aeronautics contributions. This is the reverse of what was expected in the beginning and is primarily a consequence of the unanticipated early arrival of the space age. It is interesting and important to note that any attempt at a cost-effectiveness evaluation of research aircraft in 1954 would almost certainly have either ignored or grossly undervalued the space flight aspects. At the same time, the boost-glide missions which have since been displaced by unmanned space systems, would have been exaggerated in value in any 1954 assessment. Who could have foreseen in 1954 that within 5 years the top priority goal of Western technology would be to put a man in orbit in space without delay?

Without the advantage of X-15 technology lead time, would Project Mercury and the subsequent manned space projects have been delayed? What mis fortunes might have occurred? What losses in national prestige might have resulted? Haw much was it worth to have X-15 technology in these critical times? No specific answers are possible, of course. But the existence of intangible and initially unforeseeable values is undeniable.


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