Investigating the Response of a Flexible TPS to a High Enthalpy Environment

Abstract

Flexible Thermal Protection Systems (TPS) are a key technological area required to enable inflatable and deployable decelerator concepts to be used. By using inflatable or deployable hypersonic decelerators, heavier payloads can be delivered, and high-altitude landing sites can be reached on Mars since aeroshells are no longer confined by the dimensions of the launcher fairing. European experience in testing flexible TPS concepts requires maturation in order to exploit this emerging technology. To improve the European capability, a flexible TPS concept was tested at the DLR L2K arc heated facility under flight representative conditions. The flexible TPS concept was made up of layers of CeraFib Tex 99 for the surface layers and Insulair NP 650 Plus for the inner insulation layer, all sourced from European companies. The TPS material was tested in a purpose-built sample holder in both Air and CO2 atmospheres, at heat fluxes up to 450kW/m2 and heat loads of 40.5MJ/m2. Thermocouples were placed within the layers to assist with the thermal characterisation of the response. In this paper, the results are shown and analysed using FGE's FABL and MABLE codes. FABL is a 1D, finite difference ablation code while MABLE is a 3D, finite volume ablation code. The advantage of MABLE is that multiple material layers can be modelled with and without decomposition and so is well suited to the analysis of a flexible TPS. Material models have been generated for both materials tested and the results agree well with experiment.