Today, Gas and Ice Giants are the most common exoplanets and their exploration is essential for science as well as for aerospace industry. In order to better understand the nature of these planets (atmosphere, composition, magnetosphere, gravity field, magnetic field), space research missions have been carried out in the last years. Many of these missions have concerned Jupiter, Saturn and Uranus. Thus, NASA and ESA are currently highly motivated to devise an atmospheric probe mission for Ice Giants. For an atmospheric entry into Uranus or Neptune typical velocities and stagnation enthalpies are 22 km/s and 249 MJ/kg, respectively, thus requiring the development of a proper Thermal Protection System (TPS). In these conditions the mixture is composed of molecules, atoms, ions and electrons in thermochemical non-equilibrium. The most common approach to handle thermochemical non-equilibrium is the multi-temperature model (mT). However, it was demonstrated that at hypersonic speeds internal distributions may depart from the Boltzmann one, thus mT models can introduce considerable errors. To overcome such an issue, the State-to-State (StS) approach can be employed. Since Gas and Ice Giants are mainly composed of H2 and He, the aim of this work is to perform a preliminary analysis of a solver implementing H2/He StS kinetics by solving the flow past model probes at freestream conditions that are typical of Gas or Ice Giants entries.