The investigation of the thermochemical field around planetary reentry capsules, and their experimental scaled models is made by coupling aerothermodynamic simulation of the corresponding flow field to a library of chemical kinetics of the specific atmosphere. As examples, the FIRE II reentry and TITAN aerocapture entry which have been studied in collaboration with the Hypersonics centre of the University Queensland, where scaled geometries axe tested in their expansion tube facilities. Examples are given over equivalent sphere geometries to test the models of the kinetics, and complete capsule configurations for Titan are presented with simplified models.