Tactical Ops A U.S. soldier and an Estonian soldier work in the tactical operation center during a live-fire exercise as part of Rail Gunner Rush in Tapa, Estonia, Sept. 5, 2020. The U.S. Army C5ISR (Command, Control, Computers, Communications, Cyber, Intelligence, Surveillance and Reconnaissance) Center and the Estonian Ministry of Defense have established a cyber domain working group to identify opportunities for interoperability experimentation and demonstrations. SHARE: Download: Full Size (5.59 MB) Credit: Army Spc. Ryan Barnes VIRIN: 200905-A-BJ454-906M.JPG Photo Gallery