As Secretary Pete Hegseth pushes to speed up the development and fielding of new weapons and systems, he should look to a powerful, yet underused tool: modular open systems approach.
The law already requires MOSA to be used in major warfighting programs “to the maximum extent practicable” and Secretary Hegseth’s own Systems Engineering and Architecture office has been pushing the approach since February. It is direction that, if enforced, could do more to speed acquisitions and cut costs than any process reform under consideration.
So why hasn’t it worked? Because warfighting acquisition, in practice, continues to prioritize closed, proprietary architectures. Program offices lack the expertise and incentives to enforce open standards. Industry resists sharing interface specifications that might invite competition. And without senior leaders demanding MOSA compliance, vendor-locked systems that take decades to upgrade, with every modification requiring costly negotiations with a single contractor continue to be delivered.
The inability to deliver needed capability on time and at cost helped spawn today’s wave of venture-backed defense startups. These companies offer real promise—but if they also build closed product ecosystems, they simply replace one proprietary problem with another. What the Pentagon needs is compliance with an existing framework—MOSA—that enables established primes and new entrants to compete and collaborate.
Why MOSA works better
Open architecture means clearly defined interface standards that allow modular hardware or software components—“line replaceable units”—to be independently serviced or upgraded without redesigning entire systems. As with our REMUS unmanned underwater vehicles and Odyssey advanced autonomy, built with open architecture in mind, instead of waiting years for a monolithic upgrade, our customers around the world can service or swap in new capabilities of their choice as threats emerge. An updated software package. A next-generation sensor payload. Integration happens in weeks to months, not decades.
This isn’t just faster initial acquisition. It’s continuous modernization across a system’s entire lifespan. When threats evolve, the response doesn’t require starting a new program of record. It requires competition among multiple vendors to provide the next module. Speed becomes the default, not the exception.
MOSA also lowers costs. Proprietary components are expensive to maintain and nearly impossible to upgrade without full system redesign. With MOSA standards, multiple vendors compete to provide upgrades. Competition drives down prices and allows for innovation and integration of evolving technology. Obsolescence no longer requires rebuilding from scratch. The savings compound over time as systems remain relevant longer.
Beyond cost and speed, MOSA solves a fundamental operational problem: interoperability. Realizing the vision of Combined Joint All-Domain Command and Control, or CJADC2, is impossible when proprietary interfaces trap data in silos. Open architectures make it easier for platforms, sensors, and command systems to communicate fluidly across services and with allies.
The advantages go on. In high-threat environments, battlefield systems must be reconfigurable under pressure. Swapping a degraded sensor or integrating a new electronic warfare module becomes a matter of hours, not months. Closed systems crack under stress. Modular systems adapt and keep fighting.
Modularity also helps defend against cyber attack by enabling rapid remediation of newly discovered vulnerabilities, reducing the time an adversary has to exploit vulnerable code. Open standards also enable the seamless integration of advanced cyber monitoring, detection, and response capabilities, helping to keep ahead of threats.
Perhaps most critically, open architectures strengthen the defense industrial base itself. Closed systems concentrate capability in a handful of vendors with opaque supply chains—sometimes relying on foreign parts or foreign-controlled intellectual property. MOSA expands the field, inviting innovation from established primes and agile startups alike. It ensures the Pentagon controls critical data rights and sustainment capabilities, reducing dependence on any single contractor. This is strategic resilience: an innovative, scalable, domestically controlled warfighting ecosystem.
From policy to practice
None of this is theoretical. Programs like C5ISR Modular Open Suite of Standards, or CMOSS, prove MOSA works in practice. The legal foundation exists. What’s missing is disciplined execution and cultural change.
To ensure we achieve speed as a principle, every new acquisition should include a MOSA roadmap with defined milestones and enforcement mechanisms. This includes a requirement that non-proprietary interfaces are contractually mandated and flowed down to providers of subsystems and line replaceable units without exception. This requirement will ensure acquisition executives have the tools they need to make the necessary tradeoffs to meet the goals of recent acquisition reforms. To maximize the impact of this effort, Pentagon leaders must also drive industry participation in MOSA consortia (e.g., the Open Mission Systems effort) to develop non-proprietary architectural standards aligned to acquisition milestones. Such consortia are central to the establishment of standards that align industry, promote competition, and innovation.
The Secretary’s call to prioritize “speed to capability delivery” is an opportunity to move beyond incremental process reforms and address a key cause of slow, expensive warfighting acquisition: closed, proprietary systems that resist change. Open architecture isn’t just good policy—it’s the law, and for good reason. It accelerates innovation, reduces costs, enables interoperability, and strengthens industrial resilience. Now we must act to harness it.
Andy Green is president of HII’s Mission Technologies division. HII, the nation’s largest military shipbuilder, delivers all-domain warfighting solutions to the U.S. Department of War and America’s allies worldwide.
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