Aerothermal Design, Qualification and Flight Performance

Reusable Launch Vehicle-Technology Demonstrator (RLV-TD) experiences severe thermal environment during its ascent as well as re-entry into the atmospheric regime. Structures should be designed to withstand this thermal load. Thermal environments were estimated for RLV-TD and depending on the peak heat flux and heat load, hot structure design for nose cap, wing, vertical tail and control surfaces was developed. Thermal protection system (TPS) using silica tile and flexible insulation was designed to protect the windward and leeward regions respectively. It is essential to verify and establish the design and also physically corroborate the actual thermal performance. Besides the design, the hot structures and TPS functionality as a system has to be qualified and thereby yield full confidence on the total performance during flight. To qualify the hot structures and TPS, various qualification tests were undertaken. The demonstration of their fly-ability and qualification under the combined effect of structural and thermal load was carried out successfully for all structures. This article provides details of aerothermal design of RLVTD and various qualification tests carried out. Comparison of the estimated structure temperatures with measured temperatures in flight shows the robustness of the design methodologies adopted.