A fracture control program for the reusable space shuttle booster

Abstract

This paper describes the preliminary results of structural design and analysis efforts, and the development of preliminary fracture control plans for the principal structural components of a large reusable space shuttle booster. Included are a description of the space shuttle system, its characteristics and requirements, selected approaches for fracture control, and proposed fracture control plans. The requirements of the NASA planned space shuttle vehicle for full reusability has increased the need for high reliability, precision, and development in the fracture control approach. For the space shuttle booster, it is essential that fracture control be applied to all critical structural components (i.e., tanks, aero, surfaces, thrust structure, etc.) and the fracture control approach to each component be based on its individual design conditions, design characteristics, and sensitivities to fatigue and flaw growth. Since the fracture control approach of pressure vessels is of most interest, the plan will concentrate on the main propellant tanks although other parts of the vehicle will be mentioned. The selected fracture control plan integrates the fracture control activities over the design, manufacturing, qualification, and operation phases of the space shuttle program. The various elements of the fracture control plan include design criteria, fracture mechanics analysis, proof testing, trade studies of safe-life and fail-safe design approaches and materials, provisions for maintenance and inspection, non-destructive evaluation, and a record of vehicle usage and discrepancies during its service life.