The theory of optimal flight paths goes back to 1951, when Tsien and Evans found the optimal thrust program for a vertically ascending sounding rocket. Hibbs, in 1952, solved the problem of the optimal burning program for horizontal flight of a winged, rocket propelled vehicle. Miele has carried out much work in this field, mostly using*the assumption of constant thrust, and working without the aid of a digital computer, (which is necessary to achieve results). Reference 3 gives a summary of early work in this field.

Recently, the problem of optimal climb paths of a ballistic rocket, away from the vertical, has been shown in Ref. 4 to have a simple analytic solution. The problem of a winged supersonic rocket missile, assuming the thrust acts along flight path, has been solved in Ref. 5.