Conceptual Design of the Junction between C/SiC Thermal Protection System and Anisogrid Fuselage Cold Structure

CIRA, the Italian Aerospace Research Centre, in the framework of the national space program, is carrying out two projects among the others: one is focused on a feasibility study of a future re-entry spacecraft concept with automatic re-entry and landing operational capabilities, code named USV-3; and the other is a technological project aimed at developing anisogrid lattice composite cold structures, code named ICCS. The project ICCS has the final objective of manufacturing an anisogrid composite fuselage demonstrator which is compatible with the external aero shape of the reentry vehicle USV-3. One of the technological aspects which has been taken into account in ICCS project has been the feasibility of joining the external C/SiC shingles with the internal anisogrid cold structure.The present paper illustrates the conceptual design of a typical junction between a windward shingle of the Thermal Protection System and the results of the first thermal and thermo-mechanical analyses.The choice of the most suitable means for joining such systems comes from a study on typical solutions found from literature on past projects. The initial solution has been modelled with finite elements and subjected to the reentry thermal loads in order to verify the compatibility of all materials with maximum allowed temperature. The design has been iterative until the requirement was satisfied.Finally a more detailed model has been built and analyzed both with respect to maximum heat flow during reentry and with respect to structural integrity by means of thermo-mechanical analyses, showing positive margins of safety at ultimate load.