This figure is a notional physical decomposition of a modular weapon system and highlights key open interfaces. Through this graphic, engineers can see how a broken down system can be mapped and assessed to determine which system element interfaces are suitable for open architecture solutions. The Air Force Materiel Command Systems Engineering Directorate released version 2.0 of the Guidebook for Implementing Modular Open Systems Approach in Weapon Systems, Nov. 7. The guidebook outlines concrete steps for designing a successful MOSA strategy in the Department of the Air Force.