Nuclear fratricide is a phenomenon of physics which states that "two nuclear reactions cannot occur close in time.".

In relation to nuclear warfare this is said to prevent several warheads detonating in close succession, close to the same target. "The first blast changes the molecular makeup of the second warhead and keeps it from going off."

This theory was put forward as a defense mechanism for the LGM-118 Peacekeeper missile deployment reasoning multiple detonations would be required to knock out an entire battery of missiles if sufficiently protected. This strategy was ultimately rejected though, as enemy launches can be staggered through time to ensure warheads reach their target with enough delay between them to prevent the phenomenon.

This method of using staggered launch was described by a Missileer

Missile combat crew

A missile combat crew , is a team of trained specialists manning Intermediate Range and Intercontinental Ballistic Missile systems . In the United States, men and women of the United States Air Force operate underground missile systems at launch control centers located throughout the country...

who revealed that on receiving a launch command "Some [missiles] fly immediately, some with a delay to prevent nuclear fratricide when the bombs approach their targets in 20 to 30 minutes.".