Metallic Thermal Protection Systems for future RLV's - Concept Studies and Material Investigations - 2002-01-2548
The Thermal Protection System (TPS) will be one of the most important elements of future Reusable Launch Vehicles (RLV's) and acts as a driver w.r.t. the development and production cost of the entire vehicle.
The TPS contributes to a large portion of the overall mass and defines the operational cost of a space transportation system with it's inspection, maintenance and repair activities. For these reasons the TPS is a major driver to the economical operation of a future RLV.
The most promising way to reduce the overall system cost is to minimize the effort for maintenance and repair and to allow for multiple use of this TPS.
In Europe, considerable effort has been spent to investigate future RLV concepts. Within the FESTIP study a reference concept has been chosen for further investigations and developments which was named “HOPPER”. Mission analyses performed so far for HOPPER identified large areas on the outer surface with moderate maximum temperatures during re-entry into Earth atmosphere.
Nearly 80 per cent of the entire windward surface of the vehicle will experience maximum temperatures which are in the range of 800 to 1200°C.
Application of classical ceramic TPS on these areas in the past, showed that a very high effort has to be spent for maintenance and repair of that system.
In the meantime, new alloys have been developed with superior mechanical and thermal properties which seem to be very promising if used to build a new metallic TPS. Therefore Astrium, Bremen together with a partner company has established a cooperation aiming to the common development of metallic TPS using such new alloys.
This paper describes concept studies and material investigations performed recently which form the basis for the further development.
Starting from the Astrium heritage which is the development experience for a metallic multiwall (MMW) TPS concept originally foreseen to be applied on the hypersonic transportation system SAENGER a requirements analysis in conjunction with a design tradeoff was performed which lead finally to the selection of the most promising metallic TPS concepts for the temperature ranges considered.
Concepts are studied in detail and some results of first analyses are presented within this context.
In parallel material investigations have been carried out to establish the production of suitable metallic components and joining techniques.
This paper presents the results of the investigations performed so far and provides an overview about activities to be accomplished in the near future.