Modular Open Systems Approach (MOSA)


What is MOSA

A Modular Open Systems Approach (MOSA) can be defined as a technical and business strategy for designing an affordable and adaptable system. A MOSA is the DoD preferred method for implementation of open systems, and it is required by United States law. Title 10 U.S.C. 4401(b), states all major defense acquisition programs (MDAP) are to be designed and developed using a MOSA that -

  • Employs a modular design that uses modular system interfaces between major systems, major system components and modular systems;
  • Is subjected to verification to ensure that relevant modular system interfaces comply with, if available and suitable, widely supported and consensus-based standards; or are delivered pursuant to the requirements established in FY21 National Defense Authorization Act Section 804 (a)(2)(B), including the delivery of-
  1. Software-defined interface syntax and properties, specifically governing how values are validly passed and received between major subsystems and components, in machine-readable format;
  2. A machine-readable definition of the relationship between the delivered interface and existing common standards or interfaces available in Department interface repositories; and
  3. Documentation with functional descriptions of software-defined interfaces, conveying semantic meaning of interface elements, such as the function of a given interface field;
  • Uses a system architecture that allows severable major system components at the appropriate level to be incrementally added, removed, or replaced throughout the life cycle of a major system platform to afford opportunities for enhanced competition and innovation.
  • Complies with the technical data rights set forth in 10 U.S.C. 3771-3775.

This approach integrates technical requirements with contracting mechanisms and legal considerations to support a more rapid evolution of capabilities and technologies throughout the product life cycle through the use of architecture modularity, open systems standards, and appropriate business practices. DoD seeks to yield the following benefits with a MOSA:

  • Significant cost saving or avoidance
  • Schedule reduction and rapidly deploy new technology
  • Opportunities for technical upgrades and refresh
  • Interoperability, including system of systems interoperability and mission integration
  • Other benefits during the sustainment phase of a major system

MOSA Enabling Standards

MOSA enabling standards can best be described as widely accepted, supported and consensus based standards set by recognized standards organizations or the marketplace. These standards support interoperability, portability, and scalability and are equally available to the public under fair and reasonable license terms. The Office of the Secretary of Defense (OSD) has determined continued implementation and further development of MOSA enabling standards are essential to the ability to rapidly share information across domains, with quick and affordable updates or improvements to both hardware and software components.

The Defense Standardization Program (DSP) is providing a framework and guidance for program management and Standardization Management Activities (SMAs) to develop, adopt, maintain and distribute standardization products associated with the "Modular Open Systems Standards and Specifications (MOSS)" standardization area in ASSIST. Current efforts in this area include identifying, publishing and distributing MOSA enabling standards (e.g., defense specifications and standards, non-government standards, service specific standards, etc.) in ASSIST. In partnership with OSD and the Military Services, the DSPO is working to establish a centralized MSI repository landing page to provide links to the home pages for the MSI repository indexes for the Services and other DoD components. Please stay connected to this page for updates.