This guidebook, Implementing a Modular Open Systems Approach
in Department of Defense Programs (February 2025), is a comprehensive resource for
the Department of Defense community to incorporate a modular open systems
approach (MOSA) into defense acquisition programs. The guidebook, prepared by the
Office of the Under Secretary of Defense for Research and Engineering
(OUSD(R&E)), will be updated regularly to keep pace with advancements in
the field. This guidebook is one of many steps the OUSD(R&E) is taking to
increase awareness and visibility of MOSA-related acquisition activities across
the Services.