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Title 10, Armed ForcesRelease 119-110

§4402 Requirement to Address Modular Open System Approach in Program Capabilities Development and Acquisition Weapon System Design

Title 10 › Subtitle A — General Military Law › PART V — ACQUISITION › Subpart F — Major Systems, Major Defense Acquisition Programs, and Weapon Systems Development › CHAPTER 327 — WEAPON SYSTEMS DEVELOPMENT AND RELATED MATTERS › SUBCHAPTER I — MODULAR OPEN SYSTEM APPROACH IN DEVELOPMENT OF WEAPON SYSTEMS › § 4402

Last updated Sep 23, 2026|Official source

Summary

Requires major defense acquisition programs to plan for changing needs and to handle a modular open system approach (MOSA) when used. Program capability documents must say how system performance might change over time and state the minimum capability needed for initial operations. Studies of options must consider evolutionary development, prototyping, and MOSA. If a program uses MOSA, its acquisition plan must explain the MOSA, separate the main platform from major components (including those built outside the program), describe which components may be added, removed, or replaced later, list other parts that could be added, and explain how intellectual property, technical data, systems integration, and configuration management will be handled to protect missions and information. Requests for proposals must describe MOSA and the minimum major components required. Milestone B approval cannot be given until the decision authority certifies in writing that MOSA interfaces are defined, meet section 4401(a), and the Government will get needed IP rights, or that MOSA is not practical. Military department secretaries must issue guidance to implement these rules.

Full Legal Text

Title 10, §4402

Armed Forces, Source: USLM XML via OLRC

(a)Program Capability Document.—
A program capability document for a major defense acquisition program shall identify and characterize—
(1)the extent to which requirements for system performance are likely to evolve during the life cycle of the system because of evolving technology, threat, or interoperability needs; and
(2)for requirements that are expected to evolve, the minimum acceptable capability that is necessary for initial operating capability of the major defense acquisition program.
(b)Analysis of Alternatives.—
The Director of Cost Assessment and Performance Evaluation, in formulating study guidance for analyses of alternatives for major defense acquisition programs and performing such analyses under section 139a(d)(4) of this title, shall ensure that any such analysis for a major defense acquisition program includes consideration of evolutionary acquisition, prototyping, and a modular open system approach.
(c)Acquisition Strategy.—
In the case of a major defense acquisition program that uses a modular open system approach, the acquisition strategy required under section 4211 of this title shall—
(1)clearly describe the modular open system approach to be used for the program;
(2)differentiate between the major system platform and major system components being developed under the program, as well as major system components developed outside the program that will be integrated into the major defense acquisition program;
(3)clearly describe the evolution of major system components that are anticipated to be added, removed, or replaced in subsequent increments;
(4)identify additional major system components that may be added later in the life cycle of the major system platform;
(5)clearly describe how intellectual property and related issues, such as technical data deliverables, that are necessary to support a modular open system approach, will be addressed; and
(6)clearly describe the approach to systems integration and systems-level configuration management to ensure mission and information assurance.
(d)Request for Proposals.—
The milestone decision authority for a major defense acquisition program that uses a modular open system approach shall ensure that a request for proposals for the development or production phases of the program shall describe the modular open system approach and the minimum set of major system components that must be included in the design of the major defense acquisition program.
(e)Milestone B.—
A major defense acquisition program may not receive Milestone B approval under section 4252 of this title until the milestone decision authority determines in writing—
(1)in the case of a program that uses a modular open system approach, that—
(A)the program incorporates clearly defined major system interfaces between the major system platform and major system components, between major system components, and between major system platforms;
(B)such major system interfaces are consistent with the the requirements of section 4401(a) of this title; and
(C)the Government has arranged to obtain appropriate and necessary intellectual property rights with respect to such major system interfaces upon completion of the development of the major system platform; or
(2)in the case of a program that does not use a modular open system approach, that the use of a modular open system approach is not practicable.
(f)Implementation Guidance.—
The Secretaries of the military departments shall issue guidance to implement the requirements of this section.

Legislative History

Notes & Related Subsidiaries

Editorial Notes

Amendments

2025—Subsec. (e)(1)(B). Pub. L. 119–60 substituted “the requirements of section 4401(a) of this title” for “widely supported and consensus-based standards that exist at the time of the milestone decision, unless such standards are unavailable or unsuitable for particular major system interfaces”. 2021—Pub. L. 116–283, § 1851(b)(1), renumbered section 2446b of this title as this section. Subsec. (c). Pub. L. 116–283, § 1851(b)(3)(A), substituted “section 4211” for “section 2431a” in introductory provisions. Subsec. (e). Pub. L. 116–283, § 1851(b)(3)(B), substituted “section 4252” for “section 2366b” in introductory provisions. 2019—Subsec. (f). Pub. L. 116–92 added subsec. (f). 2017—Subsec. (e). Pub. L. 115–91 substituted “in writing—” for “in writing that—” in introductory provisions and inserted “, that” after “open system approach” in introductory provisions of par. (1).

Statutory Notes and Related Subsidiaries

Effective Date

of 2021 AmendmentAmendment by Pub. L. 116–283 effective Jan. 1, 2022, with additional provisions for delayed implementation and applicability of existing law, see section 1801(d) of Pub. L. 116–283, set out as a note preceding section 3001 of this title.

Effective Date

Section effective Jan. 1, 2017, see section 805(a)(4) of Pub. L. 114–328, set out as a note under section 4401 of this title.

Reference

Citations & Metadata

Citation

10 U.S.C. § 4402

Title 10, Armed Forces

Last Updated

Sep 23, 2026

Release point: 119-110