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The Thermal Protection System (TPS) used on space shuttles protects the metallic structure from the large amounts of heat created during travel through the atmosphere, both on takeoff and reentry. The shuttle experiences high thermo‐acoustic loading and impact damage from micro‐meteorites, which can cause disbonds, delaminations, chips, cracks, and other defects to the TPS system. To enhance durability and damage tolerance, new TPS tiles with an added protective ceramic‐matrix‐composite layer are being developed. This paper explores the use of pulsed thermography as a quick, diverse, non‐destructive technique, to characterize the TPS system. The pulsed thermography images obtained are presented and analyzed.

Previous hypertext systems have been designed in a monolithic fashion. This design has inhibited the ability of hypertext systems to be extended or to interface with other systems. A new architecture for hypertext systems has been developed. This architecture is centered around the process and object-oriented models of software construction. The architecture provides hypertext functionality outside the application, allowing applications to draw upon those hypertext features appropriate to the application. The architecture also extends hypertext functionality so that inter-application as well as intra-application information links can be formed.