  a ballistic missile is a missile (rocket) that follows a ballistic flightpath 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, and its trajectory is largely 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 trajectory and spend most of their flight out of the atmosphere. shorter range ballistic missiles stay within the earth's atmosphere. == history == the v-2 rocket, developed by nazi germany, was the first short-range ballistic missile. the r-7 semyorka was the first icbm. a total of 30 nations have deployed operational ballistic missiles. development continues, with around 100 ballistic missile flight tests (not including those of the us) in 2007, mostly by china, iran and the russian federation. in 2010, the us 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.http://www.state.gov/documents/organization/140035.pdf thumb|side view of minuteman-iii icbm == flight == 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 tenths of seconds to several minutes and can consist of 
Ballistic_missiles Ballistics German_inventions Missile_types Missiles Unmanned_vehicles