DSMC Analysis of the Italian Re-Entry Nacelle for Mars Entry Missions

The rarefied regime is critical for atmospheric re-entry vehicles. Regardless of the planet, a transitional regime requiring specific techniques for aerodynamic computation exists, although the altitude and extent may vary. Direct Simulation Monte Carlo (DSMC) methods are particularly suited for such scenarios. In this work, we implemented a gas mixture model for the Martian atmosphere with eight chemical species in SPARTA, a parallel open-source DSMC code, based on a reference study of the Pathfinder capsule. The gas mixture model was validated through comparisons in axial-symmetric and 3D configurations. Building on this, the model was applied to modern scenarios, focusing on the Italian Space Agency (ASI) and European Space Agency (ESA) mission: MINI-IRENE (Maser International Nacelle for Investigating - Italian Re-Entry Nacelle). The IRENE technology is a deployable and reusable thermal protection system for entry vehicles developed for re-entry missions from Low Earth Orbit. It is currently under development for potential use in robotic Mars missions. This study presents DSMC analyses performed on the IRENE configuration under Martian atmosphere entry conditions, providing insights into the behavior of deployable entry vehicles in rarefied regimes and contributing to the development of entry technologies for future Mars missions.