Modular Open Systems Approach (MOSA)

What is MOSA?

A Modular Open Systems Approach (MOSA) is an acquisition, modular design, and technical strategy that utilizes open standards for designing an affordable and adaptable system.

What are the 5 Principles of MOSA?

1. Establish an Enabling Environment: The Program Manager (PM) establishes supportive requirements, business practices, and technology development, acquisition, test and evaluation, and product support strategies needed for the effective development of open systems.

2. Employ Modular Design: Effective modular design is contingent upon adherence to four major modular design tenets:

  1. Cohesive (contain well-focused and well-defined functionality)
  2. Encapsulated (hide the internal workings of a module’s behavior and its data)
  3. Self-contained (do not constrain other modules)
  4. Highly binned (use broad modular definitions to enable commonality and reuse)

3. Designate Key Interfaces: Interfaces should be grouped into key and non-key interfaces. Such distinction enables designers and configuration managers to distinguish among interfaces that exist between technologically stable and volatile modules, between highly reliable and more frequently failing modules, between modules that are essential for net-centricity and those that do not perform net-centric functions, and between modules that pass vital interoperability information and those with least interoperability impact.

4. Use Open Standards: Interface standards should be well defined, mature, widely used, and readily available.

5. Certify Conformance: The openness of systems is verified, validated, and ensured through rigorous and well-established assessment mechanisms, well-defined interface control and management, and proactive conformance testing. The program manager, in coordination with the user, should prepare validation and verification mechanisms such as conformance certification and test plans to ensure that the system and its component modules conform to the external and internal open interface standards allowing plug-and-play of modules, net-centric information exchange, and re-configuration of mission capability in response to new threats and evolving technologies.

How does the FACE Technical Standard and Business Approach support the Five Principles of MOSA?

1. Establish an Enabling Environment

The FACE ecosystem provides a Business Guide, Contract Guide, Software Supplier’s Getting Started Guide, and an Integrator’s Guide. There are currently tools available to create FACE Products.

2. Employ Modular Design

The FACE Technical Standard defines a Reference Architecture that abstracts capabilities into a series of segments where variance occurs. It also defines a FACE Data Architecture to facilitate integration using data models that define messages using strong semantic typing.

3. Designate Key Interfaces

Each segment defined in the FACE Reference Architecture provides open, defined interfaces. Interfaces for common services are also provided via the Operating System Segment.

4. Use Open Standards

The FACE Reference Architecture leverages only open, commonly used standards in its potential implementations. These include POSIX, ARINC 653, ARINC 661, OpenGL, more

5. Certify Conformance

FACE Conformance Program uses a third party to certify software components as being ‘fully’ conformant to the FACE Technical Standard. No partial conformance is allowed, per the FACE Approach.

What guidance has the US Department of Defense delivered to support MOSA?

 7 Jan 2019 -- Tri-Services Memo from 7: MOSAs for our Weapon Systems is a Warfighting Imperative

  • Cites FACE, SOSA, OMS/UCI, VICTORY
  • “Continued implementation of these standards … is vital to our success.”
  • “Should be included in all requirements, programming and development activities”
  • · 26 March 2019 -- Secretary of Navy issued Defense Acquisition System & Joint Capabilities Integration and Development Systems Implementation (SECNAV Instruction 5000.2F)
  • 20 March 2020 -- Army Acquisition Executive Memo from 20 March 2020: Policy Guidance on Implementing MOSA in Army Acquisition Programs and Middle Tier of Acquisition Efforts
  • 30 June 2020 -- Secretary of Air Force ordered Air Force Instruction 63-101/20-101 Integrated Life Cycle Management

Is MOSA a requirement for military programs?

Yes. MOSA is the DoD preferred method for implementation of open systems, and it is required by United States law under Title 10 U.S.C. 2446a.(b), Sec 805 which states that all major defense acquisition programs (MDAP) are to be designed and developed using a MOSA that:

  • Employs a modular design that uses major system interfaces between a major system platform and a major system component, between major system components, or between major system platforms;
  • Is subjected to verification to ensure major system interfaces comply with, if available and suitable, widely supported and consensus-based standards; and
  • 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.

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 using architecture modularity, open systems standards, and appropriate business practices. 

Reference: https://www.dsp.dla.mil/Programs/MOSA/

What are the benefits of using MOSA?

The main benefits of using a MOSA are:

  • The opportunity for significant cost-saving or avoidance
  • Schedule reduction and faster deployment of innovative technology
  • More opportunities for technical upgrades and refresh
  • Greater interoperability, including the system-of-systems interoperability and integration of mission component
  • Other benefits, including lower costs and faster deployment of the latest, more relevant defense technologies

Reference: https://www.dsp.dla.mil/Programs/MOSA/