Throughout the Department of Defense (DoD), acquisition, platform integration, and life cycle costs for weapons systems have continued to rise. Although Open Architecture (OA) interface standards are one of the primary methods being used to reduce these costs, the Air Force Rapid Capabilities Office (AFRCO) has extended the OA concept and chartered the Open Mission System (OMS) initiative with industry to develop and demonstrate a consensus-based, non-proprietary, OA standard for integrating subsystems and services into airborne platforms. The new OMS standard provides the capability to decouple vendor-specific sensors, payloads, and service implementations from platform-specific architectures and is still in the early stages of maturation and demonstration. The Air Force Research Laboratory (AFRL) - Sensors Directorate has developed the Blue Guardian program to demonstrate advanced sensing technology utilizing open architectures in operationally relevant environments. Over the past year, Blue Guardian has developed a platform architecture using the Air Force's OMS reference architecture and conducted a ground and flight test program of multiple payload combinations. Systems tested included a vendor-unique variety of Full Motion Video (FMV) systems, a Wide Area Motion Imagery (WAMI) system, a multi-mode radar system, processing and database functions, multiple decompression algorithms, multiple communications systems, and a suite of software tools. Initial results of the Blue Guardian program show the promise of OA to DoD acquisitions, especially for Intelligence, Surveillance and Reconnaissance (ISR) payload applications. Specifically, the OMS reference architecture was extremely useful in reducing the cost and time required for integrating new systems.