modular open system approach
(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 modular system interfaces between major systems, major system components and modular systems; (B) is subjected to verification to ensure that relevant modular system interfaces— (i) comply with, if available and suitable, widely supported and consensus-based standards; or (ii) are delivered pursuant to the requirements established in subsection (a)(2)(B) of section 804 of the William M. (Mac) Thornberry National Defense Authorization Act for Fiscal Year 2021, including the delivery of— (I) software-defined interface syntax and properties, specifically governing how values are validly passed and received between major subsystems and components, in machine-readable format; (II) a machine-readable definition of the relationship between the delivered interface and existing common standards or interfaces available in Department interface repositories; and (III) documentation with functional descriptions of software-defined interfaces, conveying semantic meaning of interface elements, such as the function of a given interface field; (C) uses a system architecture that allows severable major system components and modular systems 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 .