This paper discusses the optimization conducted during the definition and implementation of the operational TerraSAR-X Staring Spotlight (ST) mode. The focus is on an optimum Pulse Repetition Frequency (PRF) selection based on ambiguity and timing considerations. Both parameters will determine the product scene size and recommended incidence angle range. An extensive simulation of acquisition parameters has been carried out in order to verify the operational scenario of the ST mode. Additionally, first measurement results over distributed and point targets will be presented, showing impulse response parameters and noise characteristics.