 Anti-aircraft warfare or counter-air defense is defined by NATO as all measures designed to nullify or reduce the effectiveness of hostile air action. They include surface-based, subsurface submarine-launched and air-based weapon systems, associated command and control arrangements and passive measures e.g. barrage balloons. It may be used to protect naval, ground, and air forces in any location. However, for most countries the main effort has tended to be homeland defense. NATO refers to airborne air defense as counter-air and naval air defense as anti-aircraft warfare. Missile defense is an extension of air defense as are initiatives to adapt air defense to the task of intercepting any projectile in flight. In some countries, such as Britain and Germany during the Second World War, the Soviet Union, NATO, and the United States, ground-based air defense and air defense aircraft have been under integrated command and control. However, while overall air defense may be for homeland defense including military facilities, forces in the field, wherever they are, invariably deploy their own air defense capability if there is an air threat, the surface-based air defense capability can also be deployed offensively to deny the use of airspace to an opponent. Until the 1950s, guns firing ballistic munitions ranging from 20mm to 150mm were the standard weapons. Guided missiles then became dominant, except at the very shortest ranges as with close-in weapon systems, which typically use rotary autocannons or, in very modern systems, surface-to-air adaptations of short-range air-to-air missiles.