Simulation of radiating non-equilibrium flows around a capsule entering Titan’s atmosphere

A radiation solver and a radiative transfer solver are implemented in the open-source plasma suite PICLas to reduce uncertainties in the prediction of convective and radiative heat loads on a spacecraft’s surface during atmospheric entries, especially in non-equilibrium regions. As scientific missions to Saturn’s Titan are gaining interest, in this paper, the radiation module is extended for its complex atmosphere composed of N₂ and CH₄. Heat loads on a Genesis-type capsule with a diameter of 4.5 m entering its atmosphere are determined at two trajectory points. For a velocity of 7.3 kms⁻¹ and densities of 2×10⁻⁶ kgm⁻³ and 1×10⁻⁵ kgm⁻³ the radiative heat flux is in the same order of magnitude as the convective heat flux. Instead of assuming the electron temperature is equal to the electronic excitation temperature, the electronic excitation of each species is calculated.