The Multiple Independently Targetable Re-entry Vehicle (MIRV) is a concept and a technology that allows a single ballistic missile to carry several nuclear warheads, each capable of being directed to a different target. It is an advancement over a Multiple Re-entry Vehicle (MRV) system, where multiple warheads are dispersed but not individually aimed.
The technology was first developed by the United States in the early 1960s and first deployed on the Minuteman III Intercontinental Ballistic Missile (ICBM) in 1970. The primary problem it solved was overwhelming an adversary's anti-ballistic missile (ABM) defense system, such as the one the Soviet Union was building around Moscow. With MIRV, a single missile launch could present multiple targets, making it much more expensive for the defender to build enough interceptors.
The mechanism involves a component called a "bus" that is carried into space after the missile's main boost phase. The bus, equipped with its own guidance and propulsion system, maneuvers to a specific trajectory for the first target, releases a warhead, and then maneuvers again to set a new trajectory before releasing the next warhead, repeating the process for all warheads. This allows the warheads to strike targets that can be hundreds or even thousands of kilometers apart.
MIRV technology is closely connected to the concept of Intercontinental Ballistic Missiles (ICBMs) and Submarine-Launched Ballistic Missiles (SLBMs), as well as international arms control treaties. The technology is considered destabilizing because it incentivizes a "first strike," as an adversary could destroy multiple warheads with a single successful attack on a MIRVed missile silo. To enhance crisis stability, the United States phased out the use of MIRVs on its land-based ICBMs, completing the conversion of its Minuteman III missiles to a single warhead system in June 2014 to comply with the New START Treaty. However, the US, UK, and France still use MIRVs on their SLBMs, and Russia and China deploy them on both ICBMs and SLBMs. India successfully flight-tested its MIRV-equipped Agni-5 missile in March 2024.