Nonequilibrium Calculation of Flowfield over Galileo Probe

Abstract

Galileo Probe entry flowfield is calculated by thermochemical nonequilibrium CFD code considering the nonequilibrium ionization of H and the photo-ionization of H2. Calculations are carried out for the several trajectory points. The estimated radiative heat flux to the body surface is compared with the equilibrium calculation results. I. Introduction In planetary missions, ablative heatshield is an indispensable part of the probe for protecting the payloads from aerodynamic heating during the entry flight. In order to design the ablative heatshield, the amount of heat transferring to the probe's surface should be estimated in advance. CFD can be a helpful tool for estimating the heat transfer rate, if its reliability is validated. The flight data of Galileo Probe's entry into the atmosphere of Jupiter can be important criteria of the validation of CFD codes for the outer planetary missions in the future, since the atmosphere of Jupiter mainly consists of hydrogen and helium as well as the most of the outer planets' atmosphere. Surface recession data obtained along the Galileo Probe entry flight trajectory 1,2 have not been completely reproduced by CFD yet. The flight data has shown a surprisingly low surface recession in the stagnation region, and a surprisingly large recession in the downstream frustum region compared with the pre-flight predictions, 3 as shown