The graphic is a representation of an award or decoration of the United States military. It is in the public domain because it contains materials that originally came from a U.S. military award. As a work of the U.S. federal government, the image is in the public domain in the United States.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.