METALLIC THERMAL PROTECTION CONCEPT FOR HYPERSONIC VEHICLES

Since the first development and operation of reusable hypersonic vehicles, metallic and ceramic reradiative thermal protection systems (TPS) have been emphasized and investigated. Due to temporary advantages of rigid ceramic tiles with respect to specific weight, this protection concept has been applied primarily in the U.S. Space Shuttle Program. Meanwhile, some inherent disadvantages have led to increased development activities in the area of metallic and advanced ceramic composite TPS. Newer metallic TPS developments show competitive specific weight, and, in addition, they indicate advantages such as simpler and safer attachment and higher durability. In this paper, TPS application conditions in future European space transporter systems like SANGER (first stage: launcher vehicle, and second stage: reentry vehicle) are discussed. The predicted surface heating rate is lower for both stages than that for the HERMES reentry glider. The various load impacts on the design are outlined. Several TPS concepts have been studied and the concept selection criteria are specified. Metallic multiwall panels optionally combined with ultralight multiscreen insulations seem to be favorably applicable in the temperature range of 200-1300-degrees-C. For higher temperatures, advanced ceramic composites are preferable, if basic ceramic material problems have been solved. For temperatures ranging from 200-1300-degrees-C, a comparison of metallic and ceramic TPS design characteristics will be presented.