National Science Foundation

pwerbos@nsf.gov

International cooperation and advanced control technology could play critical roles in many areas of aerospace technology, wherethe advanced nations all share a clear common interest, which is ultimately crucial to the long-term interests of the entire human species. Among the areas which I find most interesting are hypersonic flight, space-based solar power, reconfigurable flight control, and problems of missile interception in an age when the sheer statistics of weapons proliferation pose radically new threats to the sustainability of high civilization.

This paper will focus on one of these topics – the development of hypersonic flight – where the issues focus on positive, constructive opportunities for the most advanced nations, and where US-Russian coop[eration opens the door to fundamental new breakthroughs. Public discussion of this topic poses very little risk to those nations, because terrorist groups would find it very difficult to build such a vehicle even if they could obtain a complete blueprint; on the other hand, the development of this new technology requires a continued growth in cooperation and communication between the US and Russia, and also between many groups performing open, basic scientific research at universities across a broad range of disciplines.

This paper will describe an approach to using advanced control techniques (linked with other disciplines) in order to make possible a long-term dream of the aerospace community: the development of airplanes fast enough to reach escape velocity, as airplanes, at airplane-like cost. The realization of this dream would have enormous benefits to humanity; for example, by reducing the cost of travel to earth orbit by an order of magnitude, relative to the best projected reusable rocket systems, it would expand dramatically the range of economically affordable and justifiable activities both in earth orbit and nearby space. That in turn would economically justify supplying a larger fraction of the inputs to those activities from other new activities in space; a large enough multiplier effect of this sort could allow a kind of economic takeoff effect in space, similar to the economic takeoff effects in developing nations discussed by the economist Rostow decades ago. As a practical matter, the route to this objective will not be direct. No long-term technological vision, however realistic at the time, works out exactly as anticipated. That is particularly true in a case like this, where there are many alternative pathways to the ultimate goal, and where many approaches will have to be combined together, in the end. However, the effort to pursue this vision involves the development of many key technologies which are likely to be crucial in any event, in some configuration. This paper will begin by presenting one possible vision of how to achieve this goal, in order to introduce the basic concept; then it will describe some of the outstanding scientific issues and alternatives which require further research, before we can bridge the gap between vision and reality in an efficient, realistic way.

The views expressed here are those of the author, not the views of the US government. This paper is taken in part from a preliminary patent disclosure filed on 9/24/98.