View source for Kinetic bombardment

{{Short description|Orbit to planetary surface attack with inert projectiles}}
{{redirect|Project Thor|other uses|Thor (disambiguation)}}
{{Redirect|Kinetic strike|the political euphemism|kinetic military action}}

A '''kinetic bombardment''' or a '''kinetic orbital strike''' is the hypothetical act of attacking a planetary surface with an inert [[kinetic projectile]] from [[orbit]] (''[[orbital bombardment]]''), where the destructive power comes from the [[kinetic energy]] of the projectile impacting at very high speeds. The concept originated during the [[Cold War]].

Typical depictions of the tactic are of a [[satellite]] containing a magazine of [[tungsten]] rods and a directional [[thrust]] system. When a strike is ordered, the launch vehicle [[Atmospheric entry|brakes]]<ref>{{cite book|last=Pelt|first=Michel van|title=Space Tourism: Adventures in Earth Orbit and Beyond|url=https://books.google.com/books?id=pjiuMbDxsJIC&pg=PA107|year=2005|publisher=Springer Science & Business Media|isbn=978-0-387-40213-0|page=107}}; - the word "brake" in this paragraph refers to the act of braking; the fact that by slowing the rod's orbital trajectory, the satellite can de-orbit it in order to drop it onto the planet below.</ref> one of the rods out of its orbit and into a [[suborbital]] trajectory that intersects the target. The rods would typically be shaped to minimize [[Drag (physics)|air resistance]] and thus maximize velocity upon impact.

The kinetic bombardment has the advantage of being able to deliver projectiles from a very high angle at a very high speed, making them extremely difficult to defend against. In addition, projectiles would not require explosive warheads, and&mdash;in the simplest designs&mdash;would consist entirely of solid metal rods, giving rise to the common nickname "'''rods from God'''".<ref name=PopSci-2004-06-01 /> Disadvantages include the technical difficulties of ensuring accuracy and the high costs of positioning ammunition in orbit.

== Real life concepts and theories ==
===Predecessors and early concepts===
{{see also|Smart Rocks}}
During the [[Korean War|Korean]] and [[Vietnam War|Vietnam]] Wars, there was limited use of the [[Lazy Dog (bomb)|Lazy Dog]] bomb, a kinetic projectile shaped like a conventional bomb but only about {{convert|1+3/4|in|mm}} long and {{convert|1/2|in|mm}} in diameter. A piece of sheet metal was folded to make the fins and welded to the rear of the projectile. These were dumped from aircraft onto enemy troops and had the same effect as a machine gun fired vertically.<ref>{{cite book |first=David |last=Karmes |title=The Patricia Lynn Project: Vietnam War, the Early Years of Air Intelligence |url=https://books.google.com/books?id=SQrcBQAAQBAJ |year=2014 |publisher=iUniverse |isbn=978-1-4917-5228-9 |chapter-url=https://books.google.com/books?id=SQrcBQAAQBAJ&pg=PT142 |chapter=The Lazy Dog Bomb}}</ref>{{self-published inline|date=February 2020}}<ref name="Rowley2013">{{cite book |first=Ralph A. |last=Rowley |title=Close Air Support in Vietnam |url=https://books.google.com/books?id=TcXNBAAAQBAJ |date=12 April 2013 |publisher=Lulu.com |isbn=978-1-939335-12-8 |page=[https://books.google.com/books?id=TcXNBAAAQBAJ&pg=PA43 43]}}</ref>{{self-published inline|date=February 2020}} Similar [[flechette]] projectiles have been used since [[World War I]].<ref>{{Cite web |url=https://www.thevintagenews.com/2018/03/03/the-flechettes/ |first=Ian |last=Harvey |title=WWI Flechettes – the troop piercing arrows dropped from planes onto German trenches |website=The Vintage News |date=3 March 2018 |access-date=13 August 2024}}</ref>
 
In the 1980s, another kinetic swarm system was conceptualized as a potential part of the [[Strategic Defense Initiative]], there codenamed [[Brilliant Pebbles]].<ref>{{cite web |publisher=[[Claremont Institute]] |url=http://www.missilethreat.com/missiledefensesystems/id.13/system_detail.asp |title=Brilliant Pebbles |website=MissileThreat.com |date=18 October 2010 |archive-url=https://web.archive.org/web/20101019035528/http://www.missilethreat.com/missiledefensesystems/id.13/system_detail.asp |archive-date=October 19, 2010 |access-date=March 11, 2006}}</ref><ref>{{cite web |first=Baker |last=Spring |publisher=[[The Heritage Foundation]] |url=http://www.heritage.org/Research/NationalSecurity/upload/87946_1.pdf |title='Brilliant Pebbles': The Revolutionary Idea for Strategic Defense |date=January 25, 1990 |archive-url=https://web.archive.org/web/20060317104832/http://www.heritage.org/Research/NationalSecurity/upload/87946_1.pdf |archive-date=March 17, 2006 |url-status=unfit |access-date=August 13, 2024}}</ref>

''Project Thor'' was an idea for a weapons system that launches [[Utility pole|telephone pole]]-sized kinetic [[projectile]]s made from [[tungsten]] from Earth's orbit to damage targets on the ground. [[Jerry Pournelle]] created the concept while working in operations research at [[Boeing]] in the 1950s before becoming a science-fiction writer.<ref name=NYT-2006-12-10>{{cite news |work=[[The New York Times]] |url=https://www.nytimes.com/2006/12/10/magazine/10section3a.t-9.html |title=Rods From God |first=Jonathan |last=Shainin |date=10 December 2006}}</ref><ref name=Pournelle-2006-03-06>{{cite web |publisher=The View from Chaos Manor |url=http://www.jerrypournelle.com/archives2/archives2mail/mail404.html#Thor |title=Chaos Manor Mail |first=Jerry |last=Pournelle |date=6 March 2006 |url-status=dead |archive-url=https://web.archive.org/web/20080828221908/http://www.jerrypournelle.com/archives2/archives2mail/mail404.html#Thor |archive-date=28 August 2008}}</ref>

===2003 United States Air Force proposal===
A system described in the 2003 [[United States Air Force]] report called ''Hypervelocity Rod Bundles''<ref>{{cite web | url=https://www.hsdl.org/?abstract&did=446196 | title=2003 U.S. Air Force Transformation Flight Plan |publisher= United States Department of the Air Force |via=Homeland Security Digital Library |date=November 2003 }}</ref> was that of {{convert|20|ft|m|adj=mid|-long}}, {{convert|1|ft|m|adj=mid|-diameter}} tungsten rods that are satellite-controlled and have global strike capability, with impact speeds of [[Mach number|Mach]] 10.<ref name=AT-2005-08-18>{{cite web|work=Asia Times|url=http://www.atimes.com/atimes/Front_Page/GH18Aa01.html|archive-url=https://web.archive.org/web/20051218005209/http://atimes.com/atimes/Front_Page/GH18Aa01.html|url-status=unfit|archive-date=18 December 2005|title=Star Wars: Empires strike back|first=Giuseppe |last=Anzera|date=18 August 2005|access-date=25 May 2010}}</ref><ref name=SFC-2006-03-12>{{cite web|work=San Francisco Chronicle|url=https://www.sfgate.com/opinion/article/RODS-FROM-GOD-Imagine-a-bundle-of-telephone-2539690.php|title=RODS FROM GOD / Imagine a bundle of telephone poles hurtling through space at 7,000 mph|first=John |last=Arquilla|date=12 March 2006|access-date=25 May 2010|archive-url=https://archive.today/20130202125232/http://www.sfgate.com/opinion/article/RODS-FROM-GOD-Imagine-a-bundle-of-telephone-2539690.php|archive-date=2 February 2013|quote=[Such] bundles of metal are not specifically disallowed by the 1972 Anti-Ballistic Missile Treaty, which explicitly prohibits only deploying nuclear weapons in space. The rods, however, would violate the spirit of the more general Outer Space Treaty.|url-status=live<!--Unable to verify outside the US as of 13 August 2024-->}}</ref><ref name=Guardian-2005-05-19/>

The bomb would naturally contain large kinetic energy because it moves at [[orbital speed|orbital velocities]], around {{convert|8|km/s|ft/s Mach|lk=on}} in orbit and {{convert|3|km/s|ft/s Mach|lk=on}} at impact. As the rod reenters Earth's [[Reentry|atmosphere]], it would lose most of its velocity, but the remaining energy would cause considerable damage. Some systems are quoted as having the yield of a small tactical nuclear bomb.<ref name="Guardian-2005-05-19">{{cite web|work=The Guardian|url=https://www.theguardian.com/science/2005/may/19/spaceexploration.usnews|title=Bush likely to back weapons in space|author=Julian Borger|date=19 May 2005|access-date=25 May 2010}}</ref>  These designs are envisioned as a [[bunker buster]].<ref name="SFC-2006-03-12" /><ref name="Pitts-2003-07-28">{{cite news|work=Pittsburgh Post-Gazette|title=Rods from God|first=Jack |last=Kelly|date=28 July 2003|page=A5|url=https://www.newspapers.com/newspage/94403109/}}</ref> As the name suggests, the 'bunker buster' is powerful enough to destroy a nuclear bunker. With 6–8 satellites on a given orbit, a target could be hit within 12–15 minutes from any given time, less than half the time taken by an [[Intercontinental ballistic missile|ICBM]] and without the launch warning. Such a system could also be equipped with sensors to detect incoming [[anti-ballistic missile]]-type threats and relatively light protective measures to use against them (e.g. hit-to-kill missiles or megawatt-class [[chemical laser]]). The time between deorbit and impact would only be a few minutes, and depending on the orbits and positions in the orbits, the system would have a worldwide range. There would be no need to deploy missiles, aircraft, or other vehicles.

In the case of the system mentioned in the 2003 Air Force report above, a {{convert|6.1|x|0.3|m|0}} tungsten cylinder impacting at {{convert|10|Mach|ft/s m/s}} has kinetic energy equivalent to approximately {{convert|11.5|tonTNT|lk=on}}.<ref name="USAF Report">{{Cite web|url=https://apps.dtic.mil/dtic/tr/fulltext/u2/a458089.pdf|archive-url=https://web.archive.org/web/20200807223031/https://apps.dtic.mil/dtic/tr/fulltext/u2/a458089.pdf|url-status=live|archive-date=August 7, 2020|title=US Air Force Transformation Flight Plan|access-date=14 May 2020}}</ref> The mass of such a cylinder is itself greater than {{convert|9|ST}}, so the practical applications of such a system are limited to those situations where its other characteristics provide a clear and decisive advantage—a conventional bomb/warhead of similar weight to the tungsten rod, delivered by conventional means, provides similar destructive capability and is far more practical and cost-effective.<ref>{{cite book | chapter-url=https://www.jstor.org/stable/10.7249/mr1209af.11 | jstor=10.7249/mr1209af.11 | chapter=Kinds and Capabilities of Space Weapons | last1=Preston | first1=Bob | last2=Johnson | first2=Dana J. | last3=Edwards | first3=Sean J. A. | last4=Miller | first4=Michael | last5=Shipbaugh | first5=Calvin | title=Space Weapons Earth Wars | year=2002 | pages=23–50 | publisher=RAND Corporation | isbn=9780833029379 }}</ref><ref>{{cite journal | url=https://www.jstor.org/stable/4137586 | jstor=4137586 | title=Space Weapons: Crossing the U.S. Rubicon | last1=Deblois | first1=Bruce M. | last2=Garwin | first2=Richard L. | last3=Scott Kemp | first3=R. | last4=Marwell | first4=Jeremy C. | journal=International Security | year=2004 | volume=29 | issue=2 | pages=50–84 | doi=10.1162/0162288042879922 | s2cid=57559513 | url-access=subscription }}</ref><ref>{{cite magazine | url=https://books.google.com/books?id=fAAAAAAAMBAJ | title= Is This What War Will Come To? |last=Adams|first=Eric |magazine=Popular Science | date=June 2004|pages=62-72|access-date=March 2, 2025|volume=264 |number=6|publisher= Bonnier Corporation}}</ref>

The highly elongated shape and high mass of the projectiles are intended to enhance [[sectional density]] (and therefore minimize kinetic energy loss due to air friction) and maximize penetration of hard or buried targets. The larger device is expected to be quite effective at penetrating deeply buried bunkers and other command and control targets.<ref>
{{Cite episode | title = Space Wars | url = https://www.history.com/shows/the-universe/season-4/episode-8 | access-date = 2021-02-21 | series = The Universe | series-link = The Universe (TV series) | network = [[History (American TV network)|History]] |date= 2009-10-06 |season=4 |series-no= |number=8 | df = dmy-all }}</ref>

The weapon would be very hard to defend against. It has a very high closing velocity and a small radar cross-section. The launch is difficult to detect. Any [[infrared]] launch signature occurs in orbit, at no fixed position. The infrared launch signature also has a much smaller magnitude compared to a ballistic missile launch. The system would also have to cope with atmospheric heating from re-entry, which could melt non-tungsten components of the weapon.<ref>{{Cite magazine|magazine=Wired|url=https://www.wired.com/science/discoveries/news/2004/02/62358?currentPage=2|title=Pentagon Preps for War in Space|first=Noah |last=Shachtman|date=20 February 2004|access-date=25 May 2010}}</ref>

The phrase "rods from God" is used to describe the same concept.<ref name="TWS-2005-06-08">{{cite web|work=The Weekly Standard|url=http://www.weeklystandard.com/Content/Public/Articles/000/000/005/700oklkt.asp|archiveurl=https://web.archive.org/web/20050615010041/http://www.weeklystandard.com/Content/Public/Articles/000/000/005/700oklkt.asp|archivedate=June 15, 2005|title=The Rods from God|first=Michael |last=Goldfarb|date=8 June 2005|access-date=28 May 2010}}</ref> An Air Force report called them "hypervelocity rod bundles".<ref name="PopSci-2004-06-01">{{cite web|work=Popular Science|url=http://www.popsci.com/scitech/article/2004-06/rods-god|title=Rods from God|first=Eric |last=Adams|date=June 2004|access-date=27 May 2010}}</ref>

== In science fiction ==
{{More citations needed section|date=January 2016}}

In the 1970s and 1980s, this idea was refined in science fiction novels such as ''[[Footfall]]'' by [[Larry Niven]] and [[Jerry Pournelle]] (the same Pournelle that first proposed the idea for military use in a non-fiction context), in which aliens use a Thor-type system.<ref>Niven, Larry; Pournelle, Jerry (1985). Footfall. Del Rey Books. ISBN 978-0345323446</ref> During the 1980s and 1990s, references to such weapons became a staple of science fiction [[roleplaying games]] such as ''[[Traveller (role-playing game)|Traveller]]'', ''[[Shadowrun]]'', and ''[[Heavy Gear]]'' (the first of these games naming such weapons ''ortillery'', a portmanteau of ''orbital artillery''<ref>Game Designers Workshop, Journal of the Travellers' Aid Society No. 9, 1981</ref>), as well as visual media including ''[[Babylon 5|Babylon 5's]]'' "mass drivers",<ref>Straczynski, J. Michael (Creator). Babylon 5. Warner Bros. Domestic Television Distribution, 1994–1998.</ref> the film ''[[The Last Starfighter]]'',<ref>Castle, Jonathan R. (Producer); Ritchie, Nick (Director). The Last Starfighter. Universal Pictures, 1984. ISBN 978-0425072040</ref> and the film ''[[Starship Troopers (film)|Starship Troopers]]'',<ref>Verhoeven, Paul (Director). Starship Troopers. TriStar Pictures, 1997. ISBN 978-1572973301</ref> itself an adaptation of the Heinlein [[Starship Troopers|novel of the same name]].<ref>Heinlein, Robert A. (1959). Starship Troopers. G.P. Putnam's Sons. ISBN 978-0441783588</ref>  

===Further Examples===

In ''[[The Moon is a Harsh Mistress]]'' (1966) by [[Robert A. Heinlein]], the lunar colonists repurpose a [[mass driver]] to launch large rocks at Earth as kinetic bombardment weapons. These projectiles rely solely on impact energy and are used as a form of [[asymmetric warfare]] against Earth's superior forces. The attacks serve both as a means of physical destruction and as a [[psychological weapon]] to pressure Earth into granting lunar independence.<ref>Heinlein, Robert A. (1966). The Moon is a Harsh Mistress. G.P. Putnam's Sons. ISBN 978-0312863555</ref>

''[[Call of Duty: Ghosts]]'' features two kinetic bombardment weapons named Odin and Loki as story elements in the campaign and as killstreak weapons.

In ''[[The Mote in God's Eye]]'' (1974) by [[Larry Niven]] & [[Jerry Pournelle]], kinetic orbital bombardment is depicted as a strategic military option, utilizing [[hypervelocity|high-velocity]] [[projectiles]] launched from space to inflict devastation on planetary targets. These weapons rely on pure kinetic energy rather than explosives, making them a precise and efficient alternative to [[nuclear warfare|nuclear strikes]]. The novel describes their use in planetary sieges, where spacecraft or orbital platforms fire dense, inert projectiles to penetrate defenses and infrastructure.<ref>Niven, Larry; Pournelle, Jerry (1974). The Mote in God's Eye. Simon & Schuster. ISBN 978-0671741921</ref>

A smaller "crowbar" variant is mentioned in ''David's Sling'' by [[Marc Stiegler]] (Baen, 1988). Set in the Cold War, the story is based on the use of (relatively inexpensive) information-based "intelligent" systems to overcome an enemy's numerical advantage. The orbital kinetic bombardment system is used first to destroy the Soviet tank armies that have invaded Europe and then to take out Soviet ICBM silos prior to a nuclear strike.<ref>Stiegler, Marc (1988). David's Sling. Baen Books. ISBN 978-0671653699</ref>

In ''[[Nemesis Games]]'' (2015) by [[James S.A. Corey]], kinetic orbital bombardment is depicted through the repurposing of civilian [[asteroid mining]] technology, where factions redirect space rocks as improvised weapons. Unlike traditional purpose-built kinetic strikes, this approach uses industrial infrastructure to covertly manipulate [[asteroids]], turning them into high-mass projectiles without dedicated military systems. This highlights the novel [[Dual-use technology|intersection of commercial space operations and warfare]], showcasing how everyday resource extraction methods can be weaponized in interplanetary conflict.<ref>Corey, James S.A. (2015). Nemesis Games. Orbit Books. ISBN 978-0316334716</ref>

In ''[[Revelation Space]]'' (2000) by [[Alastair Reynolds]], the assault on the world of Cerberus utilizes a two-stage kinetic bombardment strategy. First, a [[Kinetic energy weapon|relativistic mass driver]] bombards the megastructure with high-velocity projectiles to weaken its defenses. This is followed by a lighthugger, a massive interstellar vessel that deliberately crashed into the planet, delivering a [[Nanotechnology|nanotechnological warfare payload]] deep into its crust.<ref>Reynolds, Alastair (2000). Revelation Space. Gollancz. ISBN 978-0441009428</ref>

''Halo'' features the Magnetic Accelerator Cannon (MAC), or Mass Accelerator Cannon, as the primary weapon system employed by the [[United Nations Space Command]] (UNSC) on its warships and orbital defense platforms.<ref>{{cite book |last1=Staten |first1=Joseph |title=Halo: Contact Harvest |date=2007 |publisher=Tor Books |location=New York |isbn=978-0-7653-1569-4 |page=119 |edition=1st}}</ref><ref>{{cite book |last1=Patenaude |first1=Jeremy |title=Halo: The Essential Visual Guide |date=2011 |publisher=DK Publishing |location=New York, NY |isbn=978-0756675929 |page=114}}</ref> Essentially large [[coilgun]]s, MACs are capable of firing a variety of ammunition types varying on the model and bore, ranging from hyper-dense kinetic kill slugs to sub-caliber rounds to semi-autonomous drone missiles.<ref>{{cite book |last1=Peters |first1=Kenneth |title=Halo: Warfleet - An Illustrated Guide to the Spacecraft of Halo |date=2017 |publisher=Egmont Publishing |location=New York, New York |isbn=978-1681196633 |page=32}}</ref> Most predominantly featured in ''[[Halo Wars]]'' and ''[[Halo Wars 2]]'', the MAC is an ability that allows the player to utilize the UNSC ''Spirit of Fire'''s point-defense MAC for pinpoint orbital bombardment, allowing the player to heavily damage or destroy enemy units. However, there are variants of the MAC platforms mounted to various ships and stations, with the most powerful being able to fire a 3,000-ton projectile at anywhere between 0.4% and 25% the speed of light.

In ''[[Seveneves]]'' (2015) by [[Neal Stephenson]], kinetic orbital bombardment occurs as a natural consequence of the [[Moon|Moon’s]] fragmentation, resulting in a sustained bombardment of Earth by high-velocity lunar debris. The impact energy of these fragments causes widespread devastation, leading to the collapse of civilization. Unlike conventional orbital strikes, this event highlights the destructive potential of natural [[Orbital mechanics|celestial mechanics]], framing kinetic bombardment as an existential threat.<ref>Stephenson, Neal (2015). Seveneves. William Morrow. ISBN 978-0062334510</ref>

In ''[[Death's End]]'' (2010) by [[Cixin Liu]], kinetic orbital bombardment is depicted through the use of near-light-speed projectiles, where objects are accelerated to [[Relativistic speed|relativistic velocities]] to maximize destructive energy. These strikes are capable of triggering planetary-scale catastrophes, as even small masses, when moving at a significant fraction of the [[speed of light]], release immense kinetic energy upon impact. Unlike traditional orbital bombardment, which relies on gravity-assisted or mass-driver-launched projectiles, these attacks are executed with extreme precision using advanced acceleration technologies. This portrayal highlights the [[Global catastrophic risk|existential threat]] of relativistic warfare, where the sheer energy of kinetic strikes renders planetary defenses nearly obsolete.<ref>Liu, Cixin (2010). Death’s End. Chongqing Press. ISBN 978-0765377104</ref>

==See also==
* [[Concrete bomb]]
* [[Kinetic energy penetrator]]
* [[Cobalt bomb]]
* [[Prompt Global Strike]]
* [[Railgun]]
* [[Boeing X-37]]
* [[Brilliant Pebbles]]
* [[Flechette]]
* [[Fractional Orbital Bombardment System]]

==References==
{{reflist}}

==Further reading==
{{Library resources box}}

* {{Citation|publisher = RAND Corporation|title=Space Weapons, Earth Wars|year=2002|isbn=0-8330-2937-1}}

== External links ==
*{{cite web|url=http://www.weeklystandard.com/Content/Public/Articles/000/000/005/700oklkt.asp|archive-url=https://web.archive.org/web/20050609232528/http://weeklystandard.com/Content/Public/Articles/000/000/005/700oklkt.asp|url-status=dead|archive-date=June 9, 2005|title=Rods from God|publisher=[[The Weekly Standard]]}}
* {{cite web|publisher=Popular Science|url=http://www.popsci.com/scitech/article/2004-06/rods-god|title=Rods from God|date=June 2004}}
* {{cite web|author=Richard L. Garwin|url=http://fas.org/rlg/030522-space.pdf|title=Space Weapons, Not Yet|date=14 May 2003}}<!-- this is one of the sources of the Wired article -->

{{Doomsday}}
{{science fiction}}

{{Politics of outer space}}

{{DEFAULTSORT:Kinetic Bombardment}}
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