The Space Systems MOSA Interface Standards Alliance was established for the purpose of voluntary consensus and development and update of space system interface standards (in accordance with Public Law 104-113 and OMB Circular A-119) and MOSA laws as specified for major defense acquisition programs in 10 USC 2446a (renumbered 10 USC 4401), 10 USC 2446b and c.

The Space Systems MOSA Interface Standards Alliance was initiated for the purpose of developing standards to facilitate and enforce the implementation of standardized interfaces on Enterprise space systems.


In May 2020, the Office of the Undersecretary of Defense for Research and Engineering released the “Modular Open Systems Approach (MOSA) Reference Frameworks in Defense Acquisition Programs.”  It states:

Successful MOSA implementations have proved that proper application of modular approaches and flexible, open-system architectures allow for system components to evolve to respond to changing “technology, threat, or interoperability need” (P.L. 114-328 2017). Accordingly, the Department is moving from unique architectures and closed systems that are inflexible and cost-prohibitive to architectures that include the use of open interface standards with modular systems to facilitate continuous adaption and upgrades (Mattis 2018).

The “Summary of the 2018 National Defense Strategy” (Mattis 2018) emphasized that “Interoperability is a priority for operational concepts, modular force elements, communications, information sharing, and equipment” to “strengthen and evolve our alliances and partnerships into an extended network capable of deterring or decisively acting to meet the shared challenges of our time.”

There is a common thread of agreement that implementation of MOSA will enhance resiliency in future space systems but looking back, it will also help prevent issues we’re facing with some of our legacy systems.  In a 2021 article “Is the Pentagon Serious About Implementing Open Systems Architectures,” former Assistance Secretary of Defense for Systems Engineering, Mr. Stephen Welby, is quoted,

For those [legacy systems], the challenge of diminishing manufacturing sources and materiel shortages and the fact that we can often no longer find replacements for the capabilities we need to trade out to extend the life of our systems is critical. The industrial base may have gone away over time. The market for commercial components has moved on. We find ourselves increasingly challenged, and it drives the non-recurring engineering costs associated with these service life extension programs. If we were smarter about thinking about modularity and we could predict where we’d be relative to those commercial component lifecycles, we could think about making sure we’ve defined our open system interfaces in ways that bounded our exposure to many of these components and think about replacing subsystems. I think increasingly, that’s a place where we find a compelling business case for open systems.


Governing Documents

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Membership Information

All members of the MOSA Alliance receive the same benefits, including:

  • Attendance on Committees and Subcommittees
  • The ability to work on relevant standards
  • Access to all board approved standards and documents
  • Access to the members only collaboration tool

Established Company Member (More than 10,000 employees) – $5,000
Large Company Member (1001-9999 employees) – $3,000
Small Company Member (Less than 1000 employees) – $1,000
Government Entity Member  – $0
Government Support Member – $0

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