(a) Modular Open System Approach Requirement.—A major defense acquisition program that receives Milestone A or Milestone B approval after January 1, 2019, shall be designed and developed, to the maximum extent practicable, with a modular open system approach to enable incremental development and enhance competition, innovation, and interoperability.

(b) Definitions.—In this chapter:

(1) The term "modular open system approach" means, with respect to a major defense acquisition program, an integrated business and technical strategy that—

(A) 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;

(B) is subjected to verification to ensure major system interfaces comply with, if available and suitable, widely supported and consensus-based standards;

(C) 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 while yielding—

(i) significant cost savings or avoidance;

(ii) schedule reduction;

(iii) opportunities for technical upgrades;

(iv) increased interoperability, including system of systems interoperability and mission integration; or

(v) other benefits during the sustainment phase of a major weapon system; and

(D) complies with the technical data rights set forth in section 2320 of this title.

(2) The term "major system platform" means the highest level structure of a major weapon system that is not physically mounted or installed onto a higher level structure and on which a major system component can be physically mounted or installed.

(3) The term "major system component"—

(A) means a high level subsystem or assembly, including hardware, software, or an integrated assembly of both, that can be mounted or installed on a major system platform through well-defined major system interfaces; and

(B) includes a subsystem or assembly that is likely to have additional capability requirements, is likely to change because of evolving technology or threat, is needed for interoperability, facilitates incremental deployment of capabilities, or is expected to be replaced by another major system component.

(4) The term "major system interface"—

(A) means a shared boundary between a major system platform and a major system component, between major system components, or between major system platforms, defined by various physical, logical, and functional characteristics, such as electrical, mechanical, fluidic, optical, radio frequency, data, networking, or software elements; and

(B) is characterized clearly in terms of form, function, and the content that flows across the interface in order to enable technological innovation, incremental improvements, integration, and interoperability.

(5) The term "program capability document" means, with respect to a major defense acquisition program, a document that specifies capability requirements for the program, such as a capability development document or a capability production document.

(6) The terms "program cost targets" and "fielding target" have the meanings provided in section 2448a(a) of this title.

(7) The term "major defense acquisition program" has the meaning provided in section 2430 of this title.

(8) The term "major weapon system" has the meaning provided in section 2379(f) of this title.