Laydown delivery is a mode of delivery found in some nuclear gravity bombs: the bomb's descent to the target is slowed by parachute so that it lands on the ground without detonating. The bomb then detonates by timer some time later.[1] Laydown delivery requires the weapon to be reinforced so that it can survive the force of impact.[2]
Laydown modes are used to make weapon delivery survivable by aircraft flying at low level.[3] Low-altitude delivery helps hide the aircraft from surface-to-air missiles.[4] The ground burst detonation of a laydown delivered weapon is used to increase the effect of the weapon's blast on built-up targets such as submarine pens, or to transmit a shock wave through the ground to attack deeply-buried targets. An attack of this type produces large amounts of radioactive fallout.
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