The exponential cost escalation associated with design changes throughout the aerospace development cycle necessitates sophisticated optimization frameworks capable of exploring comprehensive design spaces early in the development process. This economic imperative, where design modifications can cost orders of magnitude more in later development phases, drives the need for advanced methodologies that can identify optimal solutions while maintaining computational tractability. This research develops an innovative multifidelity and multidisciplinary framework for mission-based rocket design optimization that strategically balances computational efficiency with engineering accuracy. The methodology implements a comprehensive multidisciplinary approach that integrates various physics domains required for trajectory analysis, propulsion systems, structural mechanics, and control systems, creating a holistic optimization environment.