Mid-Wave Infrared Radiation Experiments in Hypervelocity CO₂ Blunt Body Flow

Forebody and wake MWIR spectral radiance and shock shape measurements are obtained in the T5 Reflected Shock Tunnel in CO₂ flow over a 25.3:1 scaled Mars Science Laboratory (MSL) heat shield model (177.8 mm base diameter). Two conditions are developed to match the binary scaling parameter and total enthalpy at selected points on flight trajectories of the recent MSL and ExoMars missions at enthalpies of 6.1 MJ/kg and 7.7 MJ/kg, respectively. The model is mounted at a 0 degree AOA to emulate the ExoMars mission ballistic entry trajectory while the model is mounted at a 16 degree AOA for the MSL mission lifting entry trajectory. The ExoMars shock layer can be considered optically thin while boundary layer absorption occurs for the MSL forebody shock layer measurements. This work builds on our previous studies of mid-wave infrared radiation measurements in high-enthalpy ground test facilities.