NASA and Rockwell International retained our firm to review the seismic response of the Space Shuttle on the launch pad at Vandenberg Air Force Base. As part of the study, we coordinated the seismic hazard evaluation study, developed a detailed finite element model, and considered the effects on seismic response of soil-structure interaction. The results of our work were used in evaluating the risk faced by the space vehicle as it was assembled and fueled prior to launch. The goals of this seismic study were to evaluate and update the existing seismic data base and to assess the influence of soil-structure interaction on the dynamic response of the shuttle vehicle at the launch pad.