Multiple Soldier Virtual and Operational Experiments have shown that Ground Vehicle Paired Unmanned Aircraft Systems are transformative for future Army Operations. Previous prototyping exercises have demonstrated that existing Department of Defense and industry standards are insufficient in supporting the Army’s desired interoperability and capability needs. The U.S. Army chartered an effort to develop a Modular Open System Approach for Ground Vehicle Paired UAS which is still being developed. The history of the task and an outline of the architecture is presented along with lessons learned regarding MOSA initiatives and design processes which may help future MOSA efforts.