Abstract: A uniquely designed acoustic transducer comprising a stack of piezoceramic elements (other piezoelectric materials may be used) mounted upon a tuned, shaped transmit/receive head made of hardened metal alloy. The ceramic stack is preloaded to the head via a stress bolt. Insulator electrodes used in the ceramic stack are selected to minimize compliance in the stack for maximum efficiency. All the material properties, sizes, weights, etc., as well as the overall transducer design are carefully selected to act in combination to match the impedance of the load (i.e. metal structural framework). The diameter of the tip of the tuned, shaped driving head is sized such that when clamped to a metal framework, the base metal of the material just under the tip is compressed to or slightly beyond its yield point. This eliminates the requirement for surface preparation because any coatings will be displaced under the applied pressure and any surface irregularities will be flattened out.

Abstract: An autonomous ice penetrator/payload delivery system is provided which, when once launched from its parent vehicle will, upon reaching the surface of the ice automatically right itself to proper orientation with respect to the ice surface for penetration. A modified solid propellant rocket engine is used as the heat source to penetrate the ice rapidly and automatically is ignited upon the ice pentrator/payload containment vessel attaining proper orientation with its longitudinal axis substantially normal to the ice surface. The hot gasses of combustion produced by the modified rocket engine impinge upon the ice thereby melting it. As the ice is melted and penetrated, the penetrator/payload containment vessel will follow the receding ice surface either by gravity, or by motive forces provided by the modified rocket engine, or both.