New, innovative joint safety policies and requirements were developed in support of the Shuttle/Mir program, which is the first phase of the International Space Station program. This work has resulted in a joint multinational analysis culminating in joint certification for mission readiness. For these planning and development efforts, each nation's risk programs and individual safety practices had to be integrated into a comprehensive and compatible system that reflects the joint nature of the endeavor. This paper highlights the major incremental steps involved in planning and program integration during development of the Shuttle/Mir program. It traces the transition from early development to operational status and highlights the valuable lessons learned that apply to the International Space Station program (Phase 2). Also examined are external and extraneous factors that affected mission operations and the corresponding solutions to ensure safe and effective Shuttle/Mir missions.