Paper by J. W. Moore and J. R. Mitchell, Quality & Reliability Assurance Laboratory, Marshall Space Flight Center, and H. H. Trauboth, Computation Laboratory, Marshall Space Flight Center. The paper summary notes, "The advancement of the space age into increasingly complex and ambitious missions requiring the development and operation of more sophisticated and intricate launch vehicles has generated numerous problem areas. The purpose of this paper is to define the Aerospace Vehicle Simulation; discuss the relationship of this simulation to the major problem areas of checkout; describe the development and implementation of this simulation system; indicate multidiscipline applications to present and future programs."