U.S. Defense Secretary Jim Mattis  (left) visits with Gen. John E. Hyten, the commander of U.S. Strategic Command, during a visit to Offutt Air Force Base in Nebraska last week.   Credit: DoD/U.S. Air Force Staff Sgt. Jette Carr
An unarmed Minuteman 3 intercontinental ballistic missile launches from Vandenberg Air Force Base, California, during a February 2016 test.  Credit: U.S. Air Force photo by Staff Sgt. Jim Araos
An unarmed Minuteman 3 intercontinental ballistic missile launches from Vandenberg Air Force Base, California, during a February 2016 test.  Credit: U.S. Air Force photo by Staff Sgt. Jim Araos