Aerothermal Characterization of Silicon Carbide-Based TPS in High Enthalpy Airflow

Inductively-coupled plasma generators provide an ideal environment to reproduce the aerothermal heating experienced by a spacecraft re-entering a planetary atmosphere. The flight boundary layer chemistry is duplicated around a TPS model, ensuring a similarity between the flight and ground stagnation-point heat flux.

Experiments conducted in an induction plasmatron on silicon carbide-based thermal protection materials will be described. Several specimens are tested under a wide range of pressure and temperature conditions and investigated by means of infrared radiometry and optical emission spectroscopy. The plasma to which the materials are exposed is characterized in details by calorimetric and Pitot pressure measurements, and numerically rebuilt by means of a nonequilibrium boundary layer model.

The presentation will focus on the thermophysical properties of the material and their dependency on the testing environment. In particular, we will discuss the oxidation features of silicon carbide which are detected both via emission spectroscopy and post-test reflectivity measurements.