Intercontinental ballistic missile
An intercontinental ballistic missile (ICBM) is a land-based missile with a range in excess of 5500 kilometers.[1]. "Ballistic" describes its trajectory, with a powered boost phase into space, midcourse coasting along a suborbital phase, and unpowered reentry at one or more points determined by a precision navigational system.
ICBMs, variants of which are used as space launch vehicles, are categorized as "heavy" or "light". Heavy ICBMs have a total launch weight greater than 106,000 kilograms or a payload throw-weight greater than 4,350 kilograms. Heavier ICBMs can lift larger single reentry vehicles, as were needed for early high-yield thermonuclear bombs, or multiple reentry vehicles.
Guidance most often uses inertial navigtion, sensing accelerations and decelerations on the path away from a precisely surveyed launch point. Some also use celestial navigation, primarily before reentry, in which they determine their location based on the bearings to a set of stars.
References
- ↑ Federation of American Scientists, Glossary of Strategic Arms Reduction Treaty Terms