Optimization of the thermal protection system geometry for a Mars atmospheric entry vehicle

This work presents an optimization study of the geometry of the Thermal Protection System (TPS) for atmospheric entry vehicles on Mars, based on the geometry of the Apollo capsule. The main objective is to reduce the maximum thermal load while simultaneously increasing drag and maintaining sufficient lift, to improve braking capability in the upper layers of the atmosphere, where density is low. In this way, a balance is sought between the effective deceleration of the vehicle and the reduction of thermal stresses on the heat shield. The design variables considered are the geometric parameters of the forebody surface and the TPS thickness, which are iteratively adjusted during the optimization process for representative operating conditions. The analysis is carried out through numerical simulations using the open-source Computational Fluid Dynamics (CFD) code SU2 , which solves the Navier–Stokes equations for reactive mixtures under chemically non - equilibrium conditions. The optimization employs a Gradient-Based Optimization Method (GOM) and a multi-objective cost function that combines the aerodynamic coefficients and surface heat fluxes obtained from two-dimensional perfect-gas CFD simulations, used for the optimization stage. The results show that the proposed methodology accurately captures the effects of geometric modifications on the vehicle’s aerothermal performance, providing a computationally efficient tool for the preliminary design of Martian entry capsules. • Development of a gradient-based optimization method (GOM) to improve the geometry and thickness of Thermal Protection Systems for Mars-entry vehicles. • Multi-objective optimization combining aerodynamic performance (drag and lift) and thermal loads (total heat flux). • Use of CFD simulations with the open-source code SU2 to model hypersonic flow under perfect-gas and real-gas assumptions. • Validation of the optimization trends obtained with a simplified 2D perfect-gas model against more complex 3D and real-gas simulations. • Demonstration that the simplified 2D perfect-gas model can reliably predict pressure-related trends (drag, lift, aerodynamic moments) while underestimating thermal gradients. • Identification of geometric modifications that increase aerodynamic braking efficiency while reducing thermal loads. • Establishment of a computationally efficient framework for preliminary design and optimization of Mars-entry vehicles.