Numerical study on the non-equilibrium flow properties of CO₂ plasma around the catalytic wall of Mars Pathfinder spacecraft.

This article focuses on the development and application of a multi-physics numerical model to investigate the thermochemical non-equilibrium flow properties and wall-catalytic effects of carbon dioxide (CO₂) plasmas around the Mars Pathfinder spacecraft during atmospheric entry. The model integrates Navier–Stokes equations, an 11-species and 59-reaction CO₂ chemical kinetics framework, a four-temperature non-equilibrium model, and a catalytic wall surface model to simulate flow fields at various altitudes under different catalytic conditions. Results indicate that while catalytic wall conditions have minimal impact on Mach number, temperature, and pressure distributions near the spacecraft, they significantly influence the mole fractions of key chemical species—particularly increasing CO₂ and decreasing CO and O near the wall due to recombination reactions. The study also finds that medium and high catalytic coefficients produce similar effects on species distributions, with higher catalytic materials exhibiting stronger catalytic behavior, providing insights valuable for future Mars atmospheric entry mission designs.