What is a ballistic missile?
Ballistic missiles are a means to rapidly and accurately deliver a lethal payload to a target. Once its fuel has been consumed, the ballistic missile follows an elliptical orbit around the center of the Earth, defined strictly by the combination of velocity/flight angle at burnout and the Earth's gravity. By careful control of the missile during its powered flight, the payload can be very accurately placed at the desired target point.
Operational ballistic missiles are deployed in silos, on submarines, and on land-mobile launchers. Mobile missiles are favored by many nations because they can be hidden, which greatly increases their survivability.
In many short-range ballistic missiles, the entire missile remains intact until the warhead detonates. In longer-range ballistic missiles carry multiple independently targetable reentry vehicles (MIRVs), which hold up to 10 RVs per missile. RVs reenter the Earth's atmosphere at very high velocities, on the order of 4-5 miles per second.
Ballistic missiles are composed of one or more stages. Multiple-stage missiles, which are configured so that each stage has its own independent propulsion system, are more efficient for longer range missions. Intercontinental ballistic missiles (ICBMs) typically have two or three stages with powerful liquid-propellant engines or solid propellant motors that propel the payload toward the target, as well as a post-boost vehicle (PBV) with a much smaller propulsion system. Some RVs defined as maneuvering reentry vehiciles (MaRVs), have independent maneuvering capability.