Summary form only given. Fully-adaptive space-time adaptive processing (STAP) is an optimal but impractical radar processing algorithm due to the overwhelming number of operations required. Hence, many different heuristic approaches are sought to approximate the optimal method with fewer number of operations. We introduce a framework for prototyping various STAP methods on a parallel system: describing STAP methods, building execution time models for basic building blocks, and using these models to automatically optimize performance of the algorithms. We also present the performance results from a COTS PC cluster.