The term SUB MISSION SITE can be broken down into three parts: SEA (3 letters), MISSION, and SUB. SEA stands for the United States Navy's SEA, Air, and Land Teams, commonly known as SEALs. SEALs are a special operations force of the United States Navy that conduct military operations on SEA, air, and land. MISSION refers to the specific tasks that SEALs are assigned to complete. Finally, SUB is short for submarine, which is a type of vessel used by the Navy for underwater operations. Therefore, the term SUB MISSION SITE can be interpreted as a location where SEALs are sent to complete a MISSION using a submarine.