1. The missile launches out of its silo by firing its first-stage boost motor (A).
2. About 60 seconds after launch, the first-stage drops off and the second-stage motor (B) ignites. The missile shroud (E) is ejected.
3. About 120 seconds after launch, the third-stage motor (C) ignites and separates from the second stage.
4. About 180 seconds after launch, third-stage thrust terminates and the post-boost vehicle (D) separates from the rocket.
5. The post-boost vehicle maneuvers itself and prepares for re-entry vehicle (RV) deployment.
6. The RVs, as well as decoys and chaff, are deployed.
7. The RVs (now armed) and chaff re-enter the atmosphere at high speeds.
8. The nuclear warheads detonate.
Aballistic missile is a type ofmissile that follows aballistic 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 theEarth's atmosphere, while most larger missiles travel outside the atmosphere. The type of ballistic missile with the greatest range is anintercontinental ballistic missile (ICBM). The largest ICBMs are capable of full orbital flight.
These missiles are in a distinct category fromcruise missiles, which are aerodynamically guided in powered flight and thus restricted to the atmosphere.
One modern pioneer ballistic missile was the A-4,[1] commonly known as theV-2, developed byNazi Germany in the 1930s and 1940s under the direction ofWernher von Braun. The first successful launch of a V-2 was on October 3, 1942, and it began operation on September 6, 1944, againstParis, followed by an attack on London two days later. By the end of World War II in Europe in May 1945, more than 3,000 V-2s had been launched.[2] In addition to its use as a weapon, avertically launched V-2 became the first human-made object to reachouter space on June 20, 1944.[3]
In order to cover large distances, ballistic missiles are usually launched into a highsub-orbital spaceflight; for intercontinental missiles, the highest altitude (apogee) reached during free-flight is about 4,500 kilometers (2,800 mi).[11] A ballistic missile'strajectory consists of three parts orphases: 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.[12]
The boost phase is thepowered 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 multiplerocket stages.[13] Internal computers keep the missile aligned on a preprogrammed trajectory.[12] Onmulti-stage missiles, stage separation (excluding any post-boost vehicles orMIRV bus) occurs primarily during the boost phase.
The mid-course phase is the longest in the missile's trajectory, beginning with the conclusion of powered flight. When the fuel is exhausted, no morethrust is provided and the missile enters free flight. During this phase the missile, now largely consisting of awarhead or payload and possibly defensive countermeasures and small propulsion systems for further alignment toward its target, will reach itshighest altitude and may travel in space for thousands of kilometres (or even indefinitely, in the case of somefractional-orbital capable systems) at speeds of up to 7.5 to 10 kilometres per second (4 to 5 nautical miles per second).[14]
The last phase in the missile's trajectory is the terminal or re-entry phase, beginning with there-entry of the missile into the Earth's atmosphere (ifexoatmospheric)[13][14] where atmosphericdrag plays a significant part in missile trajectory, and lasts until missileimpact.[13] Re-entry vehicles re-enter the Earth's atmosphere at very high velocities, on the order of 6–8 kilometers per second (22,000–29,000 km/h; 13,000–18,000 mph) at intercontinental ballistic missile ranges.[15] 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.[14]
Ballistic missiles can be launched from fixed sites or mobile launchers, including vehicles (e.g.,transporter erector launchers),aircraft,ships, andsubmarines. Ballistic missiles vary widely in range and use, and are often divided into categories based on range. Various schemes are used by different countries to categorize the ranges of ballistic missiles:
Long- and medium-range ballistic missiles are generally designed to delivernuclear weapons because theirpayload is too limited for conventional explosives to be cost-effective in comparison to conventionalbomber aircraft.
A quasi-ballistic missile is a category ofSRBM that is largely ballistic but can perform maneuvers in flight or make unexpected changes in direction and range.[16] Large guidedMLRS rockets with range comparable to an SRBM are sometimes categorized as quasi-ballistic missiles.[17]
Many ballistic missiles reachhypersonic 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 be maneuvered before hitting their target and don't follow a simpleballistic trajectory.[22][23]
Throw-weight is a measure of the effective weight of ballistic missilepayloads. It is measured inkilograms ortonnes. Throw-weight equals the total weight of a missile'swarheads,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 launchrocket booster and launch fuel).[24] Throw-weight may refer to any type of warhead, but in normal modern usage, it refers almost exclusively tonuclear orthermonuclear 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 duringStrategic Arms Limitation Talks between theSoviet Union and theUnited States.[25] 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.[26]
The missiles with the world's heaviest payloads are the RussianSS-18 and ChineseCSS-4 and as of 2017[update], Russia was developing a new heavy-lift, liquid-propellant ICBM called theSarmat.[15]
Throw-weight is normally calculated using an optimalballistic trajectory from one point on the surface of the Earth to another. A "minimum-energy trajectory" maximizes the total payload (throw-weight) using the availableimpulse of the missile.[27] 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 evadeanti-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 nuclearfirst-strike scenario.[28] An alternate, non-military purpose for a depressed trajectory is in conjunction with thespaceplane concept with use ofairbreathing 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.[29][27]
^abChun, Clayton K. S. (2006).Thunder over the horizon: from V-2 rockets to ballistic missiles. War, technology, and history. Westport, CN.: Praeger Security International. p. 2.ISBN978-0-275-98577-6.
^abcChun, Clayton K. S. (2006).Thunder over the horizon: from V-2 rockets to ballistic missiles. War, technology, and history. Westport, Conn.: Praeger Security International. p. 4.ISBN978-0-275-98577-6.
^Science & Global Security, 1992, Vol. 3, pp.101–159 Depressed Trajectory SLBMs: A Technical Evaluation and Arms Control Possibilities[1]Archived 2013-03-18 at theWayback Machine
Needham, Joseph (1986).Science and Civilization in China: Volume 5, Chemistry and Chemical Technology, Part 7, Military Technology; the Gunpowder Epic. Taipei: Caves Books.
Bath, David W.Assured Destruction: Building the Ballistic Missile Culture of the U.S. Air Force (Naval Institute Press, 2020)online book review
Futter, Andrew (2013).Ballistic Missile Defence and US National Security Policy: Normalisation and Acceptance after the Cold War.Routledge.ISBN978-0-415-81732-5.
Neufeld, Jacob (1990).The Development of Ballistic Missiles in the United States Air Force, 1945–1960. Office of Air Force History, U.S. Air Force.ISBN0-912799-62-5.
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