A retirement ceremony will be held at the State House on Tuesday for Brigadier General John A. Hammond, who served for 30 years in the Massachusetts Army National Guard. Hammond served in all three campaigns in the global war on terror: Operation Noble Eagle, Operation Enduring Freedom, and Operation Iraqi Freedom, according to a statement from the Guard. In his career, Hammond commanded at the platoon, troop, battalion, and brigade levels as a military police, cavalry, and infantry officer, and commanded in combat at the battalion and brigade level, according to the release. The ceremony will be held at 1 p.m. in the Great Hall of Flags.