Hypersonic Flight Vehicles: Perspective and Prognosis

Although hypersonics has been with us for over 50 years, the great advantages of very high speed flight have not been brought to engineering fruition. The present paper gives a brief overview of hypersonic flight, including the often neglected chemical reactions and upper atmospheric characteristics which MUST be included for realistic studies. The lack of ground test facilities with COMPLETE simulation of hypersonic flight is, in the author's view, a major impediment to ever developing, in some rational way, hypersonic vehicles with very high performance. There has been little facility research since the early 1970's and NO continuing effort to examine possible solutions because of the long lead time required to research and test such techniques. At the same time, current and future systems, which might take advantage of a very high speed flight regime, are severely handicapped by long lead times (beyond the project plans), and the expense of funding the research and development needed. Long lead times and expensive test set-ups are required to evaluate ANY hypersonic facility proposal, but flight test development is even more costly and time consuming. Modern computational capability and new knowledge bases in several key areas have been developed (briefly reviewed in the report) BUT, detailed testing is needed to validate concepts and preliminary designs. If we can't build a ground test facility, I suggest we can't build a vehicle!