Comparative Ablation Testing of Carbon Phenolic TPS Materials in the AEDC-H1 Arcjet

Abstract

Candidate heat shield materials for hypersonic and reentry applications must be ground tested under severe heating and shear conditions representative of flight in order to validate thermal-structural performance prior to flight testing. Arc heaters have found widespread usage in the development of materials for hypersonic missiles, reentry vehicles, high-speed transports, military/civil space transportation and space access vehicles, and ordnance and munitions systems. The High-Enthalpy Ablation Test (HEAT) H1 and H3 arcjet facilities at Arnold Engineering Development Center (AEDC) fill a unique niche in providing high-pressure, high-enthalpy ground test simulations, and they have been widely utilized to test candidate thermal protection system (TPS) materials that are of interest for many hypersonic and reentry systems. H1 and H3 provide high-enthalpy test conditions simulating aeroheating environments consistent with endoatmospheric flight at velocities from 5,000 ft/s up to and exceeding 20,000 ft/s. The combination of high-enthalpy test gas and high plenum pressure makes possible heat flux simulations representing high Mach number flight at high dynamic pressures. The paper includes a description of the H1 test facility, the supporting facility systems, and the TPS material test procedure. A summary of the optical and instrumentation systems used to acquire heat shield ablation performance data for materials in a typical AEDC reentry ground test simulation is also presented.