A thermochemical nonequilibrium model of CO₂ plasma for studying flow-field properties of the spacecraft Mars Pathfinder.

This article focuses on the development and numerical simulation of a thermochemical nonequilibrium flow field model for the Mars Pathfinder spacecraft during atmospheric entry. The study establishes a multi-physics model incorporating the Navier–Stokes equations, an 11-species and 59-reaction chemical kinetic model of CO₂ plasma, and a four-temperature thermodynamic nonequilibrium framework to capture translational, rotational, vibrational, and electronic energy modes. Simulations at altitudes of 33, 30, and 21 km reveal variations in flow parameters such as temperature, pressure, Mach number, and species molar fractions, showing that CO₂ dissociates into CO within the shock layer and that nonequilibrium effects weaken with decreasing altitude. Validation against experimental data confirms the model’s predictive accuracy, providing a valuable reference for further research on Mars spacecraft aerothermal environments under thermochemical nonequilibrium conditions.