Col. John Grimm, 90th Security Forces Group commander, passes the guidon to Maj. David Lycan, 890th Missile Security Forces Squadron commander, during a change and assumption of command ceremony at F.E. Warren Air Force Base, Wyo., Sept. 20, 2017. Twentieth Air Force implemented a missile field security forces restructure that aims to increase the readiness and lethality of defenders across the Numbered Air Force. The Missile Security Operating Concept was implemented Oct. 6, 2017, significantly changing missile field security operations and addressing areas for improvement in defender culture. (U.S. Air Force photo by Glenn S. Robertson)