Thermal characterization of cork- and ceramics-based TPS in DLRs arc-heated wind tunnel L2K

Abstract

Within the RETALT project, multiple Thermal Protection System (TPS) materials have been tested, using DLR´s arc heated facility L2K in Cologne, Germany. The high enthalpy flow was used to simulate the aerothermal heating during reentry of the 1st stage of the RETALT 1 launcher. In total, 21 samples of five materials in stagnation point configuration have been tested, having two ablative cork materials and three high temperature ceramics. The cork materials by Amorim Cork Composites featured an existing material (P50) and a newly developed, trowelable cork based TPS. The ceramics were provided in cooperation with the LightCoce project. The samples were exposed to cold wall heat fluxes in the range of 200 to 800 kW/m². In addition to tests with only one heat exposure, some samples were tested 3 times at the same cold wall heat flux and same total test time, named cycle tests. Those cycle tests are intended to yield more information on a possible reuse of the materials. Surface recession and mass change is measured.