Modeling of Stardust Entry at High Altitude, Part 2: Radiation Analysis

摘要

During entry of the Stardust sample return capsule,measurements of the radiation emitted fromthe shock-heatednflow were obtained with a number of instruments. These instruments viewed the sample return capsule from annairplane located several hundred kilometers fromthe vehicle. The present study analyzes the radiation generated atntwo different high-altitude conditions. The flowfields are simulated using both continuum (computational fluidndynamics) and particle (direct simulation Monte Carlo) methods. The flow solutions provide input to a non-nequilibriumradiationmodel to compute line-of-sight spectra that are comparedwith high-resolution data takenwithnthe Echelle spectrograph during the Stardust entry. Comparisons between simulation and measurements arenpresented for air spectral features and for metal atomic lines believed to originate from evaporation of the vehiclensurface. The comparisons make it possible to identify specific aspects of the air chemistry modeling that requirenfurther work. In addition, analysis of the metal spectra provides insight into the likely sources of these impurities.