Aerothermal databases and load predictions for Retro Propulsion-Assisted Launch Vehicles (RETALT)

The assessment of thermal loads occurring on reusable launch vehicles during the entire trajectory is essential for the correct dimensioning of the thermal protection system. Due to the costs and limitations of ground-based testing for large-scale vehicles, these predictions rely intensively on numerical simulations (CFD). The need of aero-thermal databases, as a fast-response surrogate model for the aero-thermodynamic heating, arises from the practical impossibility of performing unsteady CFD analysis over the entire trajectory due to the large disparity of fluid mechanical and structural time scales. The construction of these databases is based on a representative set of CFD simulations which cover, at a minimum, the flight regimes with significant thermal loads. The aim of this paper is to analyse the results of these representative CFD simulations during both the ascent flight and atmospheric entry for the RETALT1 vehicle to show typical flow field phenomena occurring during these phases and the resulting heating patterns.