Ballistic missile

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Image:V-2 rocket diagram (with English labels).svg

A ballistic missile is a missile that follows a sub-orbital, ballistic flightpath with the objective of delivering a warhead to a predetermined target. The missile is only guided during the powered phase of flight and its course is governed by the laws of orbital mechanics and ballistics.

The first ballistic missile was the A-4, commonly known as the V-2 rocket, developed by Nazi Germany in the 1930s and 1940s under direction of Walter Dornberger. The first successful launch of a V-2 was on October 3, 1942 and began operation on September 6, 1944 against Paris, followed by an attack on London two days later. By the end of the war in May 1945 over 3000 V-2's had been launched.

A ballistic missile trajectory consists of three parts: The powered flight portion, the free-flight portion which constitutes most of the flight time, and the re-entry phase where the missile re-enters the Earth's atmosphere.

Ballistic missiles can be launched from fixed sites or mobile launchers, including vehicles (Transporter Erector Launchers, TELs), aircraft, ships and submarines. The powered flight portion can last from a few tens of seconds to several minutes and can consist of up to three rocket stages.

When in space and no more thrust is provided, the missile enters free-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 1200 km.

The re-entry stage begins at an altitude where atmospheric drag plays a significant part in missile trajectory, and lasts until missile impact.

1 Missile types
2 Specific missiles
3 Ballistic missile submarines
4 See also
5 References
6 External links

[edit] Missile types

Image:Trident II missile image.jpg

Ballistic missiles can 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.

Short-range ballistic missile (SRBM): range less than 1000 km; the three types of ballistic missile ever used in an attack were all in this category and had conventional explosives only:
Medium-range ballistic missile (MRBM): range between 1000 and 2500 km
Intermediate-range ballistic missile (IRBM): range between 2500 and 3500 km
Sub-continental ballistic missile (SCBM): range between 3500 and 5500 km
Intercontinental ballistic missile (ICBM): range greater than 5500 km, broken down into:
- Limited range intercontinental ballistic missile (LRICBM): range between 5500 and 8000 km
  - LRICBMs are also known as Long-range ballistic missiles (LRBM)
- Full range intercontinental ballistic missile (FRICBM): range between 8000 and 12,000 km
Submarine-launched ballistic missile (SLBM)

Medium to short range missiles are often called tactical or theatre ballistic missiles (TBM). Long and medium range ballistic missiles are generally designed to deliver nuclear warheads because their payload is too limited for conventional explosives to be efficient (though the US may be evaluating the idea of a conventionally-armed ICBM for near-instant global air strike capability despite the high costs<ref>Hebert, Adam J. (October 2003). "The Future Missile Force" 86 (10). Retrieved on 2006-05-26.</ref>).

Using a missile with a considerably longer range than the distance from launch site to target can make sense: it can reach a higher altitude and come down with a higher speed, making defense more difficult. For example, a missile with a range of 3000 km fired at a target that is only 500 km away could arrive at its target after having reached an altitude of about 1200 km —roughly the height reached by ICBMs. Like them, it would arrive at a speed of typically more than 6 km/s (Mach 17).

The flight phases are like those for ICBMs, except that for a range less than ca. 350 km there is no exoatmospheric phase.