Wikipedia

Ballistic missile

(Redirected from Throw weight)
For self-navigating guided constant-speed missiles, see Cruise missile.

A ballistic missile (BM) is a type of missile that uses projectile motion to deliver warheads on a target. These weapons are powered only during relatively brief periods—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 intercontinental ballistic missile (ICBM). The largest ICBMs are capable of full orbital flight.

Minuteman-III MIRV launch sequence:
  • 1. The missile launches out of its silo by firing its 1st-stage boost motor (A).
  • 2. About 60 seconds after launch, the 1st-stage drops off and the 2nd-stage motor (B) ignites. The missile shroud (E) is ejected.
  • 3. About 120 seconds after launch, the 3rd-stage motor (C) ignites and separates from the 2nd stage.
  • 4. About 180 seconds after launch, 3rd-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.

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

History

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Further information: History of rockets and Ballistics
 
Replica V-2

One modern pioneer ballistic missile was the A-4,[1] commonly known as the V-2 developed by Nazi Germany in the 1930s and 1940s under the direction of Wernher von Braun. The first successful launch of a V-2 was on October 3, 1942, and it began operation on September 6, 1944, against Paris, 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, a vertically launched V-2 became the first human-made object to reach outer space on June 20, 1944.[3]

The R-7 Semyorka was the first intercontinental ballistic missile.[4]

The largest ballistic missile attack in history took place on 1 October 2024 when the Iranian Revolutionary Guard launched about 200 missiles at Israel,[5] a distance of about 1,500 kilometers.[6][7][8] The missiles arrived about 15 minutes after launch.[9] It is believed that Iran's Fattah-1 and Kheybar Shekan missiles were used, which both have a range of about 1,400 km.[10]

 
Side view of Minuteman-III ICBM

Flight

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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 4,500 kilometers (2,800 mi).[11] 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.[12]

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.[13] Internal computers keep the missile aligned on a preprogrammed trajectory.[12] On multi-stage missiles, stage separation (excluding any post-boost vehicles or MIRV 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 more thrust is provided and the missile enters free flight. During this phase the missile, now largely consisting of a warhead or payload and possibly defensive countermeasures and small propulsion systems for further alignment toward its target, will reach its highest altitude and may travel in space for thousands of kilometres (or even indefinitely, in the case of some fractional-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 the re-entry of the missile into the Earth's atmosphere (if exoatmospheric)[13][14] where atmospheric drag plays a significant part in missile trajectory, and lasts until missile impact.[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 ICBM 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]

Types

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Trident II SLBM launched by ballistic missile submarine

Ballistic missiles can be launched from fixed sites or mobile launchers, including vehicles (e.g., transporter erector launchers), aircraft, ships, and submarines. 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 deliver nuclear weapons because their payload is too limited for conventional explosives to be cost-effective in comparison to conventional bomber aircraft.

Quasi-ballistic missiles

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A quasi-ballistic missile is a category of SRBM that is largely ballistic but can perform maneuvers in flight or make unexpected changes in direction and range.[16] Large guided MLRS rockets with range comparable to an SRBM are sometimes categorized as quasi-ballistic missiles.[17]

List of quasi-ballistic missiles

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  India
  Israel
  Soviet Union /   Russia
  United States

Hypersonic ballistic missile

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Main article: Hypersonic glide vehicle

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 be maneuvered before hitting their target and don't follow a simple ballistic trajectory.[22][23]

Throw-weight

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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).[24] 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.[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 Russian SS-18 and Chinese CSS-4 and as of 2017, Russia was developing a new heavy-lift, liquid-propellant ICBM called the Sarmat.[15]

Depressed trajectory

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Example of Depressed trajectory: Fractional Orbital Bombardment System

Throw-weight is normally calculated using an optimal ballistic trajectory from one point on the surface of the Earth to another. A "minimum-energy trajectory" maximizes the total payload (throw-weight) using the available impulse 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 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.[28] 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.[29][27]

Combat use

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The following ballistic missiles have been used in combat:

See also

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Notes

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  1. ^ Zaloga, Steven (2003). V-2 Ballistic Missile 1942–52. Reading: Osprey Publishing. p. 3. ISBN 978-1-84176-541-9.
  2. ^ Clayton K. S. Chun (2006). Thunder Over the Horizon: From V-2 Rockets to Ballistic Missiles. Greenwood Publishing Group. p. 54.
  3. ^ Wade, Mark. "Peenemuende". Astronautix.com. Archived from the original on 2005-04-25. Retrieved 2019-06-07.
  4. ^ "Launching The Space Age". airandspace.si.edu. Retrieved 2023-03-01.
  5. ^ Schneider, Tal (6 October 2024). "How effective was Iran's attack? The Israeli public doesn't have the full picture". The Times of Israel. Retrieved 27 October 2024.
  6. ^ "What to Know About Iran's Ballistic Missile Attacks and Israel's Efforts to Defend Itself | AJC". www.ajc.org. 2024-10-25. Retrieved 2024-10-27.
  7. ^ "MSN". www.msn.com. Retrieved 2024-10-27.
  8. ^ "Distance from Jerusalem, Israel to Tehran, Iran". www.geodatos.net. Retrieved 2024-10-27.
  9. ^ "What we know about Iran's latest missile attack on Israel". www.bbc.com. Retrieved 2024-10-27.
  10. ^ Doyle, Gerry (2 October 2024). "Iranian missile strike on Israel shows capability for greater scale, complexity". Reuters. Retrieved 27 October 2024.
  11. ^ "North Korea launches 'highest ever' ballistic missile". BBC. 28 November 2017.
  12. ^ a b Chun, 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. ISBN 978-0-275-98577-6.
  13. ^ a b c McFadden, Christopher (4 December 2017). "What is an intercontinental ballistic missile and how does it work?".
  14. ^ a b c Chun, 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. ISBN 978-0-275-98577-6.
  15. ^ a b "Ballistic and Cruise Missile Threat". Defense Intelligence Ballistic Missile Analysis Committee. June 2017.
  16. ^ "Why Pralay quasi-ballistic missile, tested by DRDO today, will be a 'game-changer' for Army". ThePrint. 2021-12-22. Retrieved 2022-06-21.
  17. ^ "MLRS For Army and Indigenous Capability". SPS Land Forces.
  18. ^ "Missile marvels: India makes a mark with its growing capabilities". Financialexpress. 27 December 2022. Retrieved 2022-12-28.
  19. ^ "Defence Ministry clears proposal to buy 'Pralay' ballistic missiles for Indian Army". The Economic Times. 2023-09-17. ISSN 0013-0389. Retrieved 2024-02-15.
  20. ^ "MGM-140 ATACMS Short-Range Ballistic Missile". www.militarytoday.com. Retrieved 2023-10-26.
  21. ^ "Precision Strike Missile (PrSM)". Lockheed Martin. Retrieved 2023-10-26.
  22. ^ "'National pride is at stake.' Russia, China, United States race to build hypersonic weapons". www.science.org. Retrieved 2022-11-21.
  23. ^ Gale, Alastair. "What Are Hypersonic Missiles and Who's Developing Them?". WSJ.com. Retrieved 2022-11-20.
  24. ^ "What is throw weight?". The New York Times. 15 July 1991. p. 10, Sec. A. Retrieved 13 April 2024.
  25. ^ James John Tritten, Throw-Weight and Arms Control Archived 2007-11-23 at the Wayback Machine, Air University Review, Nov-Dec 1982.
  26. ^ What Is Throw-Weight? Archived 2022-11-26 at the Wayback Machine, New York Times, July 15, 1991.
  27. ^ a b Druckmann, Erez; Ben-Asher, Joseph (28 Aug 2012). "Optimal In-flight Trajectory Modifications for Ballistic Missiles and Rockets". Journal of Guidance, Control, and Dynamics. 35 (2): 462. doi:10.2514/1.54538 – via Aerospace Research Central.
  28. ^ 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 the Wayback Machine
  29. ^ "Why North Korea's missile tests are going higher and further". Reuters. 2022-12-16. Retrieved 2024-04-13.
  30. ^ "The National Interest: Blog".
  31. ^ "Two missiles target Ethiopian airports as Tigray conflict widens". 14 November 2020.
  32. ^ "Little and large missile surprises in Sanaa and Tehran".
  33. ^ "Video Points to Azerbaijan's First Use of Israeli-Made Ballistic Missile Against Armenia". 2 October 2020.
  34. ^ "In a first, Israel shoots down a ballistic missile in space". 5 November 2023.
  35. ^ "A peek inside Houthi Rebel's recent missile strikes in Saudi Arabia". FDD's Long War Journal. 28 March 2018.
  36. ^ "Interview: Inside the Houthi arsenal that can reach Israel". Amwaj.media. Retrieved 2 November 2023.

References

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

Further reading

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  • Bath, David W. Assured Destruction: Building the Ballistic Missile Culture of the U.S. Air Force (Naval Institute Press, 2020) online book review
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