Office of the Under Secretary of Defense for Research and Engineering
This guidebook provides the Department of Defense (DoD) community, including Military Services, civilians, and DoD support contractors with information to help ensure programs incorporate a modular open systems approach (MOSA) as part of the defense acquisition program life cycle. The intended audience includes decision makers, program management offices (PMOs), program managers (PMs), and program lead systems engineers responsible for implementing and evaluating MOSA in defense programs.
Although MOSA has long been incorporated into DoD programs, this guidebook describes statute and DoD policy that now impose requirements to use MOSA. This guidebook provides best practices for planning, implementing, and evaluating MOSA, including implementation principles, benefits, challenges, and suggestions based on experience from practitioners in DoD and industry. It includes recommendations to consider when developing requests for proposals (RFPs) and evaluating planned approaches for implementing MOSA. The appendices provide supplemental information on the background efforts that have helped inform the DoD MOSA community.
The Office of the Under Secretary of Defense for Research and Engineering (OUSD(R&E)) Systems Engineering and Architecture (SE&A) prepared this guidebook and will continue to review, update, and incorporate feedback to acknowledge advances in the field.
Year published: 2025
URL: https://www.cto.mil/wp-content/uploads/2025/03/MOSA-Implementation-Guidebook-27Feb2025-Cleared.pdf