Ballistic missile

thumb|upright=1.3|Minuteman-III [[Multiple independently targetable reentry vehicle|MIRV launch sequence: ]]

A ballistic missile is a type of missile that follows a ballistic trajectory and is powered only during a relatively brief initial period—most of the flight is unpowered. Short-range ballistic missiles (SRBM) typically stay within the Earth's atmosphere, while most larger missiles travel outside the atmosphere. The type of ballistic missile with the greatest range is an intercontinental ballistic missile (ICBM). The largest ICBMs are capable of full orbital flight.

These missiles are in a distinct category from cruise missiles, which are aerodynamically guided in powered flight and thus restricted to the atmosphere.

History

upright|thumb|Replica [[V-2 rocket|V-2]]

Ballistic missiles developed from earlier rocket artillery and from the study of ballistics. Rockets had been used as weapons for centuries, including in China, the Kingdom of Mysore, and nineteenth-century European armies, but these weapons were unguided and short-ranged compared with later ballistic missiles. Modern ballistic missiles emerged from twentieth-century liquid-fuel rocketry and from attempts to deliver explosive payloads over long distances without using crewed aircraft.

V-2 and the Second World War

One of the first operational ballistic missiles was the German Aggregat 4 (A-4), better known as the V-2. It was developed by Nazi Germany during the 1930s and 1940s under a program associated with Wernher von Braun and Walter Dornberger. The first successful A-4 launch took place on 3 October 1942.

The V-2 entered combat use in September 1944. The first V-2 used in combat was fired against Paris on 6 September 1944, and attacks against London began two days later. Because it followed a high, fast ballistic trajectory and travelled faster than sound, the V-2 could not be intercepted by wartime air defenses.

After the war, the United States, the Soviet Union, and other states examined captured German missiles, documents, and personnel. This postwar transfer of V-2 technology influenced both military missile programs and early spaceflight programs.

The Soviet R-7 Semyorka was the first ICBM to complete a successful flight, on 21 August 1957. A modified R-7 launched Sputnik 1, the first artificial satellite, on 4 October 1957, linking early ICBM development with the beginning of the Space Age. The United States developed its own early ICBMs, including Atlas and Titan, followed by the solid-fuel Minuteman family.

Solid-fuel missiles improved readiness because they could be stored for longer periods and launched more quickly than many earlier liquid-fuel missiles. The Minuteman III became operational in 1970 and was the first missile to carry multiple independently targetable reentry vehicles (MIRVs). MIRVs allowed a single missile to deliver several warheads against separate targets and became an important factor in strategic nuclear planning and missile defense debates.

Submarine-launched missiles

The development of submarine-launched ballistic missiles (SLBMs) added a sea-based component to nuclear deterrence. The United States Navy developed the solid-fuel Polaris missile for launch from submerged ballistic missile submarines. USS George Washington conducted the first submerged Polaris launch on 20 July 1960 and departed on the first U.S. ballistic missile submarine deterrent patrol on 15 November 1960. SLBMs increased the survivability of nuclear forces by placing missiles on mobile and concealed platforms at sea.

Later SLBM systems, including Poseidon and Trident, increased range, accuracy, and payload compared with Polaris. The Soviet Union and other nuclear-armed states also developed submarine-launched ballistic missile forces during the Cold War.

Arms control and proliferation

Ballistic missiles became a major subject of arms control agreements. The Intermediate-Range Nuclear Forces Treaty (INF Treaty), signed by the United States and the Soviet Union in 1987, required the elimination of their ground-launched ballistic and cruise missiles with ranges between 500 and 5,500 kilometers. Strategic ballistic missiles were also covered by later strategic arms agreements, including the Strategic Arms Reduction Treaty process and New START.

Outside the U.S.–Soviet and U.S.–Russian strategic competition, shorter-range ballistic missiles proliferated widely. The Soviet Scud and its derivatives became especially common. Scud-type missiles were used during the Iran–Iraq War, including attacks on cities, and Iraq used modified Scud variants during the Gulf War.

Twenty-first century use

In the twenty-first century, ballistic missiles have remained part of both strategic arsenals and regional conflicts. They have been used or tested by states including Russia, Ukraine, Iran, North Korea, India, Pakistan, and others. During the Russian invasion of Ukraine, both ballistic and cruise missiles were used in long-range strikes, while Iran used ballistic missiles in direct attacks on Israel in 2024 and 2025. The continued spread and use of ballistic missiles has kept missile defense, early warning, and arms control central to international security debates.

Flight

In order to cover large distances, ballistic missiles are usually launched into a high sub-orbital spaceflight; for intercontinental missiles, the highest altitude (apogee) reached during free-flight is about . A ballistic missile's trajectory consists of three parts or phases: the boost phase, the mid-course phase and the terminal phase. Special systems and capabilities are required to facilitate the successful passage from one phase to the other.

The boost phase is the powered flight portion, beginning with the ignition of the engines and concluding with the end of powered flight. The powered flight portion can last from a few tenths of seconds to several minutes and can consist of multiple rocket stages.

The last phase in the missile's trajectory is the terminal or re-entry phase, beginning with the re-entry of the missile into the Earth's atmosphere (if exoatmospheric) During the beginning of this phase, the missile's trajectory is still relatively well defined, though as the missile reaches the heavier layers of atmosphere it is increasingly influenced by gravity and aerodynamic drag, which can affect its landing. Some large guided MLRS rockets, particularly those with ranges comparable to short-range ballistic missiles, blur the traditional distinction between rocket artillery and ballistic missiles and are categorized as quasi-ballistic missiles.

Examples

;

Pralay (active)
Long Range – Anti-Ship Missile (under development)

;Israel

LORA (active)

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MGM-140 ATACMS (active)
Precision Strike Missile (active)
RIM-174 Standard ERAM (SM-6) when used for surface-attack (active)

Hypersonic ballistic missile

Many ballistic missiles reach hypersonic speeds (i.e. Mach 5 and above) when they re-enter the atmosphere from space. However, in common military terminology, the term "hypersonic ballistic missile" is generally only given to those that can sustain hypersonic speeds throughout the majority of duration of flight, often with maneuvering capability that allows them to avoid following a simple ballistic trajectory.

Throw-weight

Throw-weight is a measure of the effective weight of ballistic missile payloads. It is measured in kilograms or tonnes. Throw-weight equals the total weight of a missile's warheads, reentry vehicles, self-contained dispensing mechanisms, penetration aids, and any other components that are part of the delivered payload, and not of the rocket itself (such as the launch rocket booster and launch fuel). Throw-weight may refer to any type of warhead, but in normal modern usage, it refers almost exclusively to nuclear or thermonuclear payloads. It was once also a consideration in the design of naval ships and the number and size of their guns.

Throw-weight was used as a criterion in classifying different types of missiles during Strategic Arms Limitation Talks between the Soviet Union and the United States. The term became politically controversial during debates over the arms control accord, as critics of the treaty alleged that Soviet missiles were able to carry larger payloads and so enabled the Soviets to maintain higher throw-weight than an American force with a roughly comparable number of lower-payload missiles.

The missiles with the world's heaviest payloads are the Russian SS-18 and Chinese CSS-4 and , Russia was developing a new heavy-lift, liquid-propellant ICBM called the Sarmat. By reducing the payload weight, different trajectories can be selected, which can either increase the nominal range or decrease the total time in flight.

A depressed trajectory is non-optimal, as a lower and flatter trajectory takes less time between launch and impact but has a lower throw-weight. The primary reasons to choose a depressed trajectory are to evade anti-ballistic missile systems by reducing the time available to shoot down the attacking vehicle (especially during the vulnerable burn-phase against space-based ABM systems) or a nuclear first-strike scenario. An alternate, non-military purpose for a depressed trajectory is in conjunction with the spaceplane concept with use of airbreathing jet engines, which requires the ballistic missile to remain low enough inside the atmosphere for air-breathing engines to function.

In contrast, a "lofted" trajectory is frequently used for testing purposes, as it reduces the range of the missile (allowing for a controlled and observed impact), as well as signals a lack of hostile intention with the test.

LORA
MGM-140 ATACMS
OTR-21 Tochka
Qaher-1/2M
Scud
V-2
Zolfaghar
Kh-47M2 Kinzhal
Oreshnik

Notes

References

Needham, Joseph (1986). Science and Civilization in China: Volume 5, Chemistry and Chemical Technology, Part 7, Military Technology; the Gunpowder Epic. Taipei: Caves Books.

External links

Missile Threat: A Project of the Center for Strategic and International Studies