10-04-2017, 08:36 PM
A ballistic missile is a missile that follows a ballistic trajectory with the objective of delivering one or more warheads to a predetermined target. A ballistic missile is only guided during relatively brief periods of flight (there are unguided ballistic missiles as well, such as 9K52 Luna-M, although these may well be considered rockets), and most of its trajectory is unpowered and governed by gravity and air resistance if in the atmosphere. This contrasts to a cruise missile, which is aerodynamically guided in powered flight. Long range intercontinental ballistic missiles (ICBM) are launched at a steep, sub-orbital flight trajectory and spend most of their flight out of the atmosphere. Shorter range ballistic missiles stay within the Earth's atmosphere.
Rockets have been used as weapons for a long time (see History of rockets). A pioneer ballistic missile was the A-4, commonly known as the V-2 rocket 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 May 1945, over 3,000 V-2s had been launched.
The R-7 Semyorka was the first intercontinental ballistic missile.
A total of 30 nations have deployed operational ballistic missiles. Development continues with around 100 ballistic missile flight tests in 2007 (not including those of the US), mostly by China, Iran, and the Russian Federation.[citation needed] In 2010, the U.S. and Russian governments signed a treaty to reduce their inventory of intercontinental ballistic missiles (ICBMs) over a seven-year period (to 2017) to 1550 units each.
