AeroSoft proposes to develop an application programming interface (API) to connect single-physics based analysis tools used in thermal protection system (TPS) sizing and assessment for trajectory-shaping and reentry vehicles. The API will be based on the message passing interface (MPI) program to allow for efficient execution in parallel computing environments. For the Phase I, the API will couple the CFD flow solver GASP with the material response code DIABLO. A trajectory sizing simulation will be performed for a reentry vehicle in order to demonstrate the proposed concept. In a Phase II, the API will be extended to support additional CFD flow solvers and material response codes. This will allow the end user to select both the CFD flow solver and material response code for use in reentry type simulations where ablation is modeled. The API may also be extended to other research areas such as aero-elasticity