WikipediaExtracts:Intercontinental ballistic missile
Extracted from Wikipedia --
An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than 5,500 kilometres (3,400 mi), primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapons can also be delivered with varying effectiveness but have never been deployed on ICBMs. Some modern designs support multiple independently targetable reentry vehicles (MIRVs), allowing a single missile to carry several warheads, each of which can strike a different target. The United States, Russia, China, France, India, the United Kingdom, Israel, and North Korea are the only countries known to have operational ICBMs. Pakistan is the only nuclear-armed country that does not possess ICBMs.
ICBM development was a central part of the nuclear arms race of the Cold War, with early development led by the Soviet Union and the US. The world's first ICBM was the R-7 Semyorka, tested in 1957. Early designs used liquid propellant, often cryogenic, which require fuelling before launch, meaning high response time and low availability. Solid-propellant ICBMs do not require fuelling, having a much lower response time. ICBMs also shifted from early missile silo fields to later truck-based transporter erector launchers. Many have been adapted into space launch vehicles. The permanent members of the United Nations Security Council all possess submarine-launched ballistic missiles with intercontinental range.
Early ICBMs had limited precision, which made them suitable for use only against 'area' targets, such as cities. They were seen as a "safe" basing option, one that would keep the deterrent force close to home where it would be difficult to attack. Attacks against military targets (especially hardened ones) demanded the use of a more precise, crewed bomber. Second- and third-generation designs (such as the LGM-118 Peacekeeper) dramatically improved accuracy to the point where even the smallest point targets can be successfully attacked.
ICBMs are differentiated by having greater range and speed than other ballistic missiles: intermediate-range ballistic missiles (IRBMs), medium-range ballistic missiles (MRBMs), short-range ballistic missiles (SRBMs) and tactical ballistic missiles.
