Editing Intercontinental ballistic missile (section)

== Flight phases ==
The following flight phases can be distinguished:<ref>Intercontinental Ballistic Missiles https://fas.org/nuke/intro/missile/icbm.htm {{Webarchive|url=https://web.archive.org/web/20151126100103/https://fas.org/nuke/intro/missile/icbm.htm |date=26 November 2015 }}</ref><ref>[http://airpower.airforce.gov.au/APDC/media/PDF-Files/Pathfinder/PF305-Three-Stages-of-the-Inter-Continental-Ballistic-Missile-Flight.pdf Three Stages of the Inter-Continental Ballistic Missile (ICBM) Flight] {{Webarchive|url=https://web.archive.org/web/20190313035229/http://airpower.airforce.gov.au/APDC/media/PDF-Files/Pathfinder/PF305-Three-Stages-of-the-Inter-Continental-Ballistic-Missile-Flight.pdf |date=13 March 2019 }}</ref>

# [[Boost phase]], which can last from 3 to 5 minutes. It is shorter for a [[solid-fuel rocket]] than for a [[liquid-propellant rocket]]. Depending on the trajectory chosen, typical burnout speed is {{convert|4|km/s|abbr=on}}, up to {{convert|7.8|km/s|abbr=on}}. The altitude of the missile at the end of this phase is typically {{convert|150|to|400|km|abbr=on}}.
# [[Midcourse phase]], which lasts approx. 25 minutes, is [[sub-orbital spaceflight]] with the flightpath being a part of an [[ellipse]] with a vertical major axis. The [[apogee]] (halfway through the midcourse phase) is at an altitude of approximately {{convert|1200|km|abbr=on}}. The [[semi-major axis]] is between {{convert|3186|and|6372|km|abbr=on}} and the projection of the flightpath on the Earth's surface is close to a [[great circle]], though slightly displaced due to earth rotation during the time of flight. In this phase, the missile may release several independent warheads and [[penetration aid]]s, such as metallic-coated balloons, aluminum [[Chaff (radar countermeasure)|chaff]], and full-scale warhead [[decoy]]s.
# [[Atmospheric reentry|Reentry]]/Terminal phase, which lasts two minutes starting at an altitude of {{convert|100|km|abbr=on|disp=semicolon}}. At the end of this phase, the missile's payload will impact the target, with impact at a speed of up to {{convert|7|km/s|abbr=on}} (for early ICBMs less than {{convert|1|km/s|abbr=on}}); see also [[maneuverable reentry vehicle]].

ICBMs usually use the trajectory which optimizes range for a given amount of payload (the ''minimum-energy trajectory''); an alternative is a [[depressed trajectory]], which allows less payload, shorter flight time, and has a much lower apogee.<ref>Science & Global Security, 1992, Volume 3, pp. 101–159 Depressed Trajectory SLBMs: A Technical Evaluation and Arms Control Possibilities [http://www.princeton.edu/sgs/publications/sgs/pdf/3_1-2gronlund.pdf] {{Webarchive|url=https://web.archive.org/web/20130318120315/http://www.princeton.edu/sgs/publications/sgs/pdf/3_1-2gronlund.pdf|date=18 March 2013}}</ref>