<p>The accelerating digital transformation in the aerospace and defense sectors underlines a pressing need for refined, standardized methodologies for integrating digital tools into mission engineering (ME).  Existing literature reveals a distinct gap in the practical application of Digital Engineering (DE) and Model-Based Systems Engineering (MBSE) within ME, particularly due to the lack of clear guidelines for implementation. Recognizing DE and MBSE's potential to manage complex systems, this thesis puts forth a novel DE framework specifically designed for ME to streamline digital tool integration.</p> <p><br></p> <p>The research approach includes a thorough literature review, the development and application of a unique framework for an active debris remediation mission, and the examination of case studies. The findings inform the ongoing digital transformation efforts in the defense and aerospace sectors, offering valuable insights into the real-world application of DE and MBSE within ME. This study focuses on the early-stage, holistic-view design processes of mission and system-of-systems, aiming to establish a robust foundation for detailed lower-level engineering design.</p> <p><br></p> <p>By exploring how to leverage current practices to develop a framework that supports digital artifacts and tools, assessing the framework's improvements, and exploring possible quantification of its impact, this thesis charts a path toward the successful execution of complex mission objectives in the digital era.</p>