A Modular Open Systems Approach (MOSA) is a technical and business strategy mandated by the U.S. Department of War for designing affordable and adaptable systems through modular design and open standards. These open standards are widely supported, consensus-based specifications that promote interoperability, portability, and scalability across different products and services to facilitate competition, innovation, and cost-effectiveness throughout the system's lifecycle. By using open standards, MOSA aims to create systems with loosely coupled, highly cohesive modules that can be independently upgraded or replaced, avoiding vendor lock-in and enabling rapid technology insertion. In critical areas like defense, seamless communication between systems is paramount for achieving comprehensive situational awareness and enabling coordinated action. The MOSA ecosystem - depicted below - depends upon active involvement by multiple stakeholders across the Department of War.
The FACE Approach and ecosystem address all five of the MOSA Principles and integrates both the technical and business practices that establish a standard Common Operating Environment (COE) to support portable capabilities across avionics systems. The following represents the five MOSA Principles and aspects of the FACE Approach and ecosystem that address each one:
Resources/Materials:
Office of the Under Secretary of War for Research and Engineering (OUSW ((R&E)): https://www.cto.mil/sea/mosa/
FACE® Business Guide: Guidance in the Value Proposition and Business Case for the FACE Approach, Version 3.1
DOD Guidebook: Implementing a Modular Open Systems Approach in Department of Defense Programs
https://www.cto.mil/wp-content/uploads/2025/03/MOSA-Implementation-Guidebook-27Feb2025-Cleared.pdf
Title 10 §4401 - Requirement for modular open system approach in major defense acquisition programs
https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title10-section4401&num=0&edition=prelim
Defense Standardization Program
https://www.dsp.dla.mil/
Tri-Service Memo Updates – MOSA Guidance
https://www.dsp.dla.mil/Portals/26/Documents/PolicyAndGuidance/Memo-Modular%20Open%20Systems%20Approach%202024.pdf?ver=LEtJPJFqXWFHGdhSeJsu4w%3d%3d
