This study presented a development of design and testing of a metallic thermal protection system (TPS) for spaceplane vehicles. A metallic TPS was proposed to shield the fuselage of a spaceplane vehicle from the extreme heat flux for returned missions. A conceptual design of a metallic TPS panel which consisted of a hot load-carrying structure, a low thermal conductivity thermal insulation, support brackets, and a cool structure, was modified from the ARMOR panel developed by NASA. The thermal load was selected from a specific location on the X-33 spaceplane (5.5 W/cm~2). A transient semi-infinite heat transfer model was used to predict the required thickness of the thermal insulation for an allowable temperature at the cool structure. Due to high stresses and heat shorts in bracket support structures, a thin strip with a brazed joint was used to connect the hot structure and the cool structure. A prototype metallic TPS panel and supporting hardware made of S304 stainless steel were fabricated for thermomechanical testing in room conditions. A panel-to-panel gap in panel assemblies was designed to prevent possible contact between two adjacent panels. A numerical analysis was conducted to determine whether the designed gap would change thermal responses at the cool structure as well as at supporting hardware structures. A non-contact thermal-mechanical measurement method was employed to measure full-field temperatures and deformations of the cool structure and supporting hardware structures. A comparison of temperature responses and panel deformations was performed between numerical analysis and experimental testing. The results indicate that the current metallic TPS panel satisfied the design requirements in terms of temperature and permanent deformation limits. The panel-to-panel gap affected significantly the temperature rise in the cool structure and supporting hardware structures. The experimental method provided a good approach to testing TPS panels at the early stage of spaceplane development.
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