print font size font_plus font_minus font_reset


Modular Open Systems Approach

The Department of Defense’s (DoD) modular open systems approach (MOSA) is to design systems with highly cohesive, loosely coupled, and severable modules that can be competed separately and acquired from independent vendors. This approach allows the Department to acquire warfighting capabilities, including systems, subsystems, software components, and services, with more flexibility and competition. MOSA implies the use of modular open systems architecture, a structure in which system interfaces share common, widely accepted standards, with which conformance can be verified.

DoD is actively pursuing MOSA in the life-cycle activities of its major defense acquisition programs (MDAP) and major automated information systems (MAIS), in large part due to the rapid evolution in technology and threats that require much faster cycle time for fielding and modifying warfighting capabilities. As part of a comprehensive systems engineering strategy, MOSA can accelerate and simplify the incremental delivery of new capabilities into systems.

Thus DoD MOSA is an integrated business and technical strategy to achieve competitive and affordable acquisition and sustainment of a new or legacy system or component over the system life cycle.

MOSA Benefits

DoD seeks five primary benefits of MOSA:

  1. Enhance competition – open architecture with severable modules, allowing components to be openly competed.
  2. Facilitate technology refresh – delivery of new capabilities or replacement technology without changing all components in the entire system.
  3. Incorporate innovation – operational flexibility to configure and reconfigure available assets to meet rapidly changing operational requirements.
  4. Enable cost savings/cost avoidance – reuse of technology, modules, and/or components from any supplier across the acquisition life cycle.
  5. Improve interoperability – severable software and hardware modules to be changed independently.

MOSA in DoD Policy and Guidance

Enclosure 1, section E1.1.27. Systems Engineering of the DoDD 5000.01 (The Defense Acquisition System) highlights consideration of MOSA by all programs: Acquisition programs shall be managed through the application of a systems engineering approach that optimizes total system performance and minimizes total ownership costs. A modular, open-systems approach shall be employed, where feasible. DoDI 5000.02 (Operation of the Defense Acquisition System) further discusses open systems architecture (OSA) in Enclosure 3 (Systems Engineering), Section 14: Program managers are responsible for applying open systems approaches in product designs where feasible and cost-effective.

The Defense Acquisition Guidebook (DAG) Section 3-2.4.1 discusses benefits of MOSA and best practices for programs.

Program Planning

Program managers are expected to plan for implementing MOSA and to include a summary of such planning as part of the Systems Engineering Plan and the overall Acquisition Strategy. The summary of the MOSA planning should address the following three areas:

  1. How MOSA fits into a program's overall acquisition process and strategies for acquisition, technology development, and test and evaluation.
  2. What steps a program will take to analyze, develop, and implement a system or a system-of-systems architecture based on MOSA principles.
  3. How the program intends to monitor and assess its MOSA implementation progress and ensure system openness.

The DoD Open Systems Architecture Data Rights Team released the DoD Open Systems Architecture Contract Guidebook for Program Managers, v.1.1 , dated June 2013. The guidebook provides recommendations for writing an OSA-based statement of work, guidance on special interest requirements, recommended contract line items, and guidance on obtaining intellectual property and data rights to support full life-cycle competition and recommended Contract Data Requirements Lists.

Programs can tailor the principles described in the guidebook to the acquisition of any system or service. The guide is intended to augment, rather than replace, existing contractual source materials such as the Federal Acquisition Regulation (FAR) and the Defense Federal Acquisition Regulation Supplement (DFARS). Users should consult the most recent versions of the FAR and DFARS, in addition to the guidebook, when developing acquisition materials.

For more information on MOSA, please see Defense Acquisition University (DAU) Acquisition Community Connection (ACC) Modular Open Systems Approach (MOSA) Community of Practice (CoP).