This legislation mandates the Secretary of Defense to establish and maintain a joint reserve detachment for the Defense Innovation Unit (DIU). It achieves this by amending Section 1766(a) of title 10, United States Code, specifically changing the discretionary language from "may establish" to the imperative "shall establish and maintain." The core purpose of this change is to formalize and ensure the permanent existence and ongoing support for a dedicated reserve component within the DIU. This aims to provide consistent and specialized reserve personnel to enhance the DIU's mission of integrating commercial technology solutions into the Department of Defense.