**Abstract**

The goal of this work is to give optimum aerothermal solutions for thermal protection of the nose wall of space shuttles during atmospheric reentry, where the air flow is hypersonic, nonequilibrium reactive flow (vibrational and chemical) behind detached shock waves, it's governed by Navier–Stokes equations with chemical reaction source terms, and modelled using five species (N2, O2, NO, N, O) and Zeldovich chemical scheme with five reactions. This study which simulates the flow using the software Fluent v.19 focuses on the comparison between three protection techniques based on the repulsion of the shock wave, the first is geometric, it consists in introducing a spike that makes the right shock move away from the nose of the shuttle, this allows the endothermic physicochemical processes of dissociation and ionization to absorb heat, the second technique is based on an opposite jet configuration in the frontal region of the nose, this jet allows to push the strong shock, and consequently reduce the heat released, the last technique is the assembly of the two previous techniques; Jets nearby the spike noses were set up in front of the blunt body to reconfigure the flow field and reduce aerodynamic overheating. The opposing jet model reduces the heat at the nose by 12.08% compared to the spike model and by 20.36% compared to the spike jet model. The flow field reconfiguration was the most important factor in heat reduction, according to the quantitative analysis, a combination parameter was given as the main criterion for designing spiked bodies with opposing jets for the goal of heat reduction based on the locations of the reattached shock and its interaction with the conical shock. The results obtained are in good agreement with the specialized literature.

**Keywords:** hypersonic reactive flows, non-equilibrium, dissociation, opposing jet, blunt spike, Lobb sphere
