The Navy released their MOSA Guidebook, Version 1.0, in January 2025. It is reposted with permission from the Navy’s document custodian.

Summary of the U.S. Navy’s MOSA Guidebook

The Naval MOSA Guidebook (Version 1.0) serves as a comprehensive reference for implementing MOSA within Navy acquisition programs. Published by the Assistant Secretary of the Navy for Research, Development, and Acquisition (ASN-RDA), the guidebook outlines the strategic, technical, and business processes necessary to develop interoperable, modular, and upgradable weapon systems.

This guide aligns with Title 10 U.S. Code Sections 4401, 4402, and 4403, which mandate MOSA implementation across major defense acquisition programs (MDAPs). It provides structured methodologies to improve adaptability, innovation, and lifecycle cost efficiency while ensuring compliance with DoD acquisition policies.

---

Key Sections and Takeaways

Clocking in at just under 40 pages of pithy content, the Guide is broken into 10 Sections that should be pretty familiar to anyone in an MDAP.

1. Introduction
2. Purpose & Applicability
3. MOSA Benefits and Requirements
4. MOSA Process
5. Acquisition Strategies
6. Technical Standards and Interfaces
7. Considerations within a Systems Engineering Plan (SEP)
8. Considerations across Systems Engineering Technical Reviews (SETR)
9. MOSA Training and Resources
10. References

Takeaways

• The guidebook is intended for all Naval acquisition programs, covering both new programs and modernization efforts.
  • It ensures that MOSA principles are embedded within all acquisition pathways of the Adaptive Acquisition Framework (AAF).
  • Encourages the use of digital engineering tools and Model-Based Systems Engineering (MBSE) to support modular design.
• MOSA Benefits & Legal Requirements
  • Operational Flexibility: Rapid technology insertion and system adaptability.
  • Cost Reduction: Reduces total lifecycle costs through competition and technology refresh.
  • Innovation & Competition: Promotes vendor competition by leveraging open architectures.
  • Interoperability: Ensures cross-service and multi-platform compatibility.
  • Technology Refresh: Simplifies obsolescence management through modular upgrades.
• MOSA Implementation Process Guidance
  • Use of MOSA in Modernization of Current Programs (e.g. focus on component modularization)
    • Identify service life, obsolescence risk, and threat environment considerations.
    • Encourage incremental MOSA adoption, take on parts of the whole.
  • New Programs for full adoption of MOSA (in keeping with their legal requirement to “Employ a Modular Design”)
    • Establish MOSA objectives early in program planning.
    • Utilize reference architectures and open standards.
    • Develop an Open Systems Management Plan (OSMP).
• Key Engineering Processes:
  • Modular Decomposition: Breaking down system functions into modular, interchangeable components.
  • Functional vs. Physical Decomposition: Ensuring loose coupling and high cohesion in system design.
  • Open Interfaces: Using widely accepted, consensus-based standards for seamless integration.
  • Intellectual Property (IP) Considerations: Establishing a “Gray Box” approach to balance vendor IP rights with government modularity needs.
• Technical Standards & Systems Engineering Guidance
  • Provides guidance on selecting open standards, including Future Airborne Capability Environment (FACE), Open Mission Systems (OMS), Sensor Open Systems Architecture (SOSA), and VICTORY.
  • Emphasizes conformance validation to ensure modularity and vendor-agnostic integration.
  • Discusses System-of-Systems (SoS) interoperability, ensuring modular components work across platforms.
• Systems Engineering & Test Integration
  • Systems Engineering Plan (SEP): How MOSA principles should be incorporated into program technical planning.
  • Systems Engineering Technical Reviews (SETRs): Guides teams in assessing MOSA implementation in design reviews, test planning, and verification phases.
  • Test & Evaluation (T&E) Framework: Ensures modular components are evaluated independently before full system integration.
• MOSA Training & Resources
  • Lists training programs and resources from Defense Acquisition University (DAU), OUSD(R&E), and NDIA.
  • Provides access to MOSA compliance assessment tools, including the MOSA Program Assessment and Rating Tool (PART).

---

Recommendations for Version 2 and Other Services

It is way too early for any kind of formal recommendations, the best way to know if a guide works is to try it out and, through use, determine how we can make it better. That said, I did have some initial thoughts on my first read through the novella.

The Role of Architects

Architecture is mentioned in the Introduction and throughout the document, which is a net positive. The recommendation, however, highlights a general need across the DoD to recognize the role and credentials of Architects as well. Note that you first encounter the term “architect” on page 16, without a qualifying definition:

This resource will help engineers and program managers to leverage work and share across the community of system architects.

The lack of credentials for Systems Engineering by OPM has long been a complaint (most are categorized as “General Engineer”) and it is even more dire for recognition of Architects. We have proper certifications for cybersecurity (e.g. Security+, CISSP, etc.) and these are appropriate subsets of the role an Architect performs. A competent person who understands things relevant to this domain is key to to sign off on architectural products before they go into the world of budgets and policy that often read the “blueprints” with glossy eyes and much caffeine before making decisions about the programs. The NDIA Architecture Committee is actively working on precisely this set of recommendations and hope to give them to the Navy in time for a V2.

The Contracting Execution for Component Acquisition

Another recommendation I would make to accompany the guidance is to beef up the content regarding contracting best practices. This is mentioned in the Introduction, and then 3 other times in the document the word is used, however one of those is the main point that it is found elsewhere and not in the guide itself:

Guidance for architecture, contracting, and a reference to Defense Acquisition University training are also available on this website.

While certainly a good summary and useful resource, the specifics of contracting using Other Transaction Authorities, such as the ATI managed Aviation and Missile Technology Consortium (AMTC), would likely have been useful. For example, and disclaimer, the AMTC where I serve on the Executive Committee and has helped foster MOSA tasks and requirements and was one of the sponsors of the first ever MOSA Summit. There is a great video from the former DoD Chief Technology Officer here from that event. However, that is an Army contract and the Navy (while free to use it) has different vehicles – so one may not expect more than a footnote on these (here is a filtered list of 8 OTAs the Navy helped set up). What the recommendation I offer is that, regardless of what contracting vehicle, the methods for acquiring at the component level are largely mysterious to program managers given “whole program” budgets and short timelines, so some additional guidance would help. I offer to the community that we can provide some augmentation to the Navy guide in the the form of recommendations for industry collaboration on this venue, and of course we do that at the Summit every year already.

The Importance of Continuous Integration

The ongoing learning we have from the commercial software practice of CI/CD pipeline management is still nascent in complex systems development, especially in defense. That said, it is a hot topic and one eagerly being explored on modern systems in development. It is, however, notably absent from this version of the guide. To be sure, it is found in plenty of other new studies and experiments, thus probably too early to have been included for standardized guidance across the Navy. An honorable mention is worth a footnote here.

Conclusion

The Naval MOSA Guidebook is an essential resource for DoD acquisition professionals, engineers, and program managers working on Navy and Marine Corps systems. It provides a clear and actionable roadmap to achieving interoperability, cost efficiency, and rapid capability evolution. Naval acquisition teams can use this guide to help ensure compliance with statutory MOSA requirements while enhancing warfighting readiness and technological superiority. I would recommend it to program managers from the sibling services and commercial ventures looking to adopt MOSA as well!