The Raytheon Common Operating Environment (RTN-COE) is a TRL-9 level integrated real-time operating environment that has been utilized in 40 plus Army, Navy, and Air Force programs. RTN-COE was created in 2000-2001 as an open architecture instantiation of the US Army’s Weapons Systems Technical Architecture Working Group (WSTAWG) Operating Environment API and has since been propagated throughout the company. This paper will describe the evolution RTN-COE and specifically how RTN-COE is a key enabler of the Raytheon Tactical Plug-and-Play Framework that meets the low latency requirements associated with closed-loop operations with sensors, while also providing a gateway to the C2 applications within this framework. Finally this paper will elaborate upon the design considerations addressed by RTN-COE that have enabled it to: facilitate digital backbone integration, maximize scalability, enable multi-company software integration to shared processors, and promote software reuse and portability.