NASA has established a comprehensive policy and guidelines for accomplishing NASA programs and projects. The implementing guideline, NPR 7120.5C, NASA Program and Project Management Processes and Requirements, establishes how programs and projects are to be conducted consistent with Agency strategic planning. In concert with these guidelines, managers must meet the requirements of multiple stakeholders and customers. The successful management of programs and projects has always been a key requirement for NASA to meet its mission and a disciplined approach to program and project management is essential to meet this goal. The Process Based Mission Assurance (PBMA) model provides a structured approach to meeting the combined safety, mission assurance, and risk management requirements within program/project management across the program or project lifecycle.

The PBMA model builds upon the previously established NASA models of systems engineering and program/process management and complements existing NASA models.

The phases reflect the changing nature of the work that needs to be performed as the system matures. These stages each include a safety and mission assurance function to help ensure that the system is safe for people and property, the risks to schedule and cost are mitigated, and NASA maintains visibility into activities conducted by its subcontractors. The safety and mission assurance function increases in importance as the phases do not occur sequentially. As the program is executed, events may invalidate or modify goals and requirements.

These modifications may impact the program decisions surrounding acceptable risks, either technical or programmatic, that the manager accepts in meeting the overall program goals. The PBMA model provides a framework for analyzing the safety and mission assurance impacts, permitting structured comparisons among alternatives and relative assessments of changes in the overall safety and risk posture as the program is executed.