Anti-ship mines, also called proximity mines, are explosives that can be placed at fixed points in space. They are designed to explode when spacecraft come within a particular range, inflicting heat and projectile damage on anything nearby. Mines are used by the military for purposes of area denial and are often abandoned if unused during a conflict, making former battlefields dangerous to traverse. Anti-ship mines were used extensively in former Perry Line systems during the Xi’an-Human Cold War (2530-2792). Many were abandoned, and remain active and dangerous in spite of cleanup efforts.