Ablation Experiments of Porous Carbon-based Heat-resistant Materials in High-enthalpy Air Plasma Freejets

Abstract

When a sample return capsule enters the Earth's atmosphere, a strong shock wave is generated in front of the capsule and it receives severe aerodynamic heating. An ablation method is the effective thermal protection one to protect the capsule from the heating. In the future, capsules are expected to be larger and to increase reentry speed. Therefore, the capsules will be exposed to more severe aerodynamic heating. In this experiment, porous carbons with different pore diameters (5 μm, 10 μm, and 25 μm), and porous carbons impregnated with cyanoacrylate were used as test pieces. It was found that there were differences in wear time and wear behavior depending on the test pieces. Furthermore, the effective heat of ablation was calculated by conducting an experiment using an automatic position control system that can detect the tip of the test piece and control it to the target position. The effective heat of ablation of porous carbon impregnated with cyanoacrylate (5 μm) was about 2.8 MJ/kg.