This thesis presents the optimization and development of a proprietary Computational Fluid Dynamics (CFD) code for hypersonic flow applications, carried out in collaboration with Thales Alenia Space. The initial phase of the work focused on restoring and modernizing the existing FORTRAN code to ensure full functionality for both two-dimensional and three-dimensional geometries. The solver was then parallelized using Windows MPI to enhance computational efficiency and scalability across multiple processors. The final stage involved the validation of the code through simulations of benchmark hypersonic configurations, representative of typical experimental and numerical test cases available in literature. Particular attention was devoted to assessing the influence and accuracy of the implemented physical models, including those governing high-temperature effects and shock interactions.