Abstract; Zusammenfassung; Acknowledgement; Table of Contents; List of Figures; List of Tables; Symbols; Acronyms and Abbreviations; 1. Introduction; 2. The Generic Simulator; 3. General Model Development; 4. Gravity Probe B; 5. Application to Gravity Probe B; 6. Simulator Verification and Model Improvement; 7. Conclusion; A. Module and Feature Verification; References