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| {{hatnote|Not to be confused with [[Raygun]], a type of gun common in science fiction. For other uses, see [[Space gun (disambiguation)]].}}
| | Greetings! I am Myrtle Shroyer. Years in the past we moved to North Dakota. Hiring is her working day job now but she's usually wanted her personal business. To do aerobics is a factor that I'm totally addicted to.<br><br>my web blog; [http://miniURL.Fouiner.info/healthyfooddelivery98296 meal delivery service] |
| [[File:Quicklauncher.jpg|thumb|The [[Quicklaunch]]er spacegun]]
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| A '''space gun''' is a method of launching an object into [[outer space|space]] using a large [[gun]], or [[cannon]]. It provides a method of [[non-rocket spacelaunch]].
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| In the [[Project HARP]] a [[United States Navy|U.S. Navy]] {{convert|16|in|mm|abbr=on}} 100 [[Caliber#Caliber as measurement of length|caliber]] gun was used to fire a {{convert|180|kg|lb|abbr=on}} slug at 3600 m/s or {{convert|12960|kph|mph|abbr=on}}, reaching an apogee of {{convert|180|km|mi|abbr=on}}, hence performing a [[suborbital spaceflight]]. However, a space gun has never been successfully used to launch an object into orbit.
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| == Technical issues ==
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| The large [[g-force]] experienced by a [[Ballistics|ballistic]] projectile would likely mean that a space gun would be incapable of safely launching [[human]]s or delicate instruments, rather being restricted to [[freight]], fuel or ruggedized satellites.
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| Atmospheric drag also makes it more difficult to control the trajectory of any projectile launched, subjects the projectile to extremely high forces, and causes severe energy losses that may not be easily overcome.
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| ===Getting to orbit===
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| A space gun, by itself, is not capable of placing objects into stable orbit around the object (planet or otherwise) from which it is launched. The laws of two-body gravitation make it impossible to reach a stable orbit without an active payload which performs orbital correction burns to change the shape of its orbit after launch. The orbit is a [[parabolic orbit]], a [[hyperbolic orbit]], or part of an [[elliptic orbit]] which ends at the planet's surface at the point of launch or another point. This means that an uncorrected ballistic payload will always strike the planet within its first orbit unless the velocity was so high as to reach or exceed [[escape velocity]].
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| [[Isaac Newton]] avoided this objection in his thought experiment by positing an impossibly tall mountain from which his cannon was fired. If in a stable orbit, the projectile, however, would still tend to circle the planet and strike the point of launch (see [[Newton's cannonball]]).<ref>{{cite book|last=Newton|first=Isaac|title=A Treatise of the System of the World|year=1728|publisher=F. Fayram|pages=6-12|url=https://play.google.com/books/reader?id=rEYUAAAAQAAJ&printsec=frontcover&output=reader&authuser=0&hl=en&pg=GBS.PA4}}</ref><ref>[[Newton's cannonball]]</ref>
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| As a result, all payloads intended to reach a closed orbit need at least to perform some sort of course correction to create another orbit that does not intersect the planet's surface. A rocket can be used for additional boost as planned in both [[Project_HARP#Martlet_projectiles|Project HARP]] and the [[Quicklaunch]] project. The magnitude of such may be small; for instance, the [[StarTram|StarTram Generation 1]] reference design involves a total of 0.6 km/s of rocket burn to raise [[perigee]] well above the atmosphere when entering a 8 km/s [[Low Earth Orbit]].<ref>{{cite web|url=http://www.startram.com/resources|title=StarTram2010: Maglev Launch: Ultra Low Cost Ultra High Volume Access to Space for Cargo and Humans|publisher=startram.com|accessdate=April 28, 2011}}</ref>
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| In a [[Three-body_problem#Gravitational_systems|three-body]] or larger system, a [[gravity assist]] trajectory might be available such that a carefully aimed [[escape velocity]] projectile would have its trajectory modified by the gravitational fields of other bodies in the system such that the projectile would eventually return to orbit the initial planet using only the launch [[delta-v]].<ref>{{cite journal|last=Clarke|first=Victor C., Jr.|title=An Essay On the Application and Principle of Gravity-Assist Trajectories For Space Flight|page=7|date=1970-04-10|url=http://gravityresearchfoundation.org/pdf/awarded/1970/clarke.pdf|accessdate=2013-08-13|publisher=Jet Propulsion Laboratory, California Institute of Technology|quote=By induction then, it is obvious that the process of diverting a spacecraft from one planet to another might be continued indefinitely, if the planets were in favorable positions.}}</ref><ref>{{cite journal|last=Minovitch|first=Michael|title=A Method For Determining Interplanetary Free-Fall Reconnaissance Trajectories|series=Jet Propulsion Laboratory Technical Memos|number=TM-312-130|pages=38-44|date=August 23, 1961|url=http://www.gravityassist.com/Letters/LD-1.pdf#page=24}}</ref>
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| === Acceleration ===
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| A space gun with a "[[gun barrel]]" of length (<math>l</math>), and the needed velocity (<math>v_e</math>), the acceleration (<math>a</math>) is provided by the following formula:
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| :<math> a = \frac{v_e^2}{2l} </math>
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| For instance, with a space gun with a vertical "gun barrel" through both the [[Earth's crust]] and the [[troposphere]], totalling ~60 km of length (<math>l</math>), and a velocity (<math>v_e</math>) enough to escape the Earth's gravity ([[escape velocity]], which is 11.2 km/s on Earth), the acceleration (<math>a</math>) would theoretically be more than 1000 m/s<sup>2</sup>, which is more than 100 [[g-force]]s, which is about 3 times the [[G-force#Human_tolerance_of_g-force|human tolerance to g-force]]s of maximum 20 to 35 ''g''<ref name="Purley">{{cite web| author=Anton Sukup| title=''David PURLEY'' Silverstone crash| year=1977| url=http://www.asag.sk/bio/purley.htm| accessdate=July 31, 2006}}</ref> during the ~10 seconds such a firing would take. However, a space gun with a circular track could utilize much lower accelerations because its effective track length is infinite (though the centripetal acceleration at high speed could be enormous, depeding on the size of the circle).{{cn|date=October 2012}}
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| ==Practical attempts==
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| [[Image:Big Babylon sections at Fort Nelson.JPG|300px|thumb|Two sections of the [[Project Babylon]] gun]]
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| [[Image:Project Harp.jpg|left|thumb|140px|[[Project HARP]], a prototype of a space gun.]]
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| The German [[V-3 cannon]] program (less well known than the [[V-2 rocket]] or [[V-1 flying bomb]]), during the Second World War was an attempt to build something approaching a space gun. Based in the [[Pas-de-Calais]] area of [[France]] it was planned to be more devastating than the other [[Nazi]] 'Vengeance weapons'. It was destroyed by [[RAF]] bombing using [[Tallboy bomb|Tallboy]] [[blockbuster bomb]]s in July 1944.<ref>{{cite web|author=RAF staff |date=6 April 2005 |url=http://www.raf.mod.uk/bombercommand/diary.html |work=Bomber Command: Campaign Diary |title=RAF History - Bomber Command 60th Anniversary |publisher=RAF |archiveurl=http://webarchive.nationalarchives.gov.uk/20070706011932/http://www.raf.mod.uk/bombercommand/jul44.html |archivedate=6 July 2007|accessdate=23 October 2013}}</ref>
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| On the practical side, the most prominent recent attempt to make a space gun was artillery engineer [[Gerald Bull]]'s [[Project Babylon]], which was also known as the 'Iraqi supergun' by the media. During Project Babylon, Bull used his experience from [[Project HARP]] to build a massive cannon for [[Saddam Hussein]], leader of [[Ba'athist Iraq]]. Bull was assassinated before the project was completed.
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| === Super High Altitude Research Project ===
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| Since Bull's death, few have seriously attempted to build a space gun. Perhaps most promisingly, the US [[Ballistic Missile Defense]] program sponsored the [[Super High Altitude Research Project]] (SHARP) in the 1980s. Developed at [[Lawrence Livermore Laboratory]], it is a [[light gas gun]] and has been used to test fire objects at [[Mach number|Mach 9]].
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| === Quicklaunch ===
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| After cancellation of SHARP, lead developers [[John Hunter (scientist)|John Hunter]] founded the Jules Verne Launcher Company in 1996 and the [[Quicklaunch]] company. As of September 2012, Quicklaunch was seeking to raise $500 million to build a gun that could refuel a [[propellant depot]] or send bulk materials into space.<ref>{{cite web | url=http://quicklaunchinc.com/ | title=quicklaunchinc.com | accessdate=November 11, 2011}}</ref><ref>{{cite web | url=http://www.astronautix.com/lvs/julncher.htm | title=Jules Verne Launcher Company Concept | publisher=astronautix.com | accessdate=November 11, 2011}}</ref><ref>{{cite web | url=http://www.popsci.com/technology/article/2010-01/cannon-shooting-supplies-space | title=A Cannon for Shooting Supplies into Space | publisher=popsci.com | accessdate=November 11, 2011}}</ref>
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| [[Ram accelerator]]s have also been proposed as an alternative to light gas guns. Other proposals use electromagnetic techniques for accelerating the payload, such as [[coilgun]]s and [[railgun]]s.
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| ==In fiction==
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| [[Image:FETMlaunch.jpg|right|thumb|150px|The firing of a space gun in Jules Verne's ''From the Earth to the Moon'']]
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| The first publication of the concept may be [[Newton's cannonball]] in the 1728 book ''A Treatise of the System of the World'', although it was primarily used as a [[thought experiment]] regarding gravity.<ref>[http://www.vectorsite.net/tarokt_4.html vectorsite.net > [4.0] Space Guns] v1.1.4 / chapter 4 of 7 / 01 jun 08 / greg goebel / public domain</ref>
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| Perhaps the most famous representation of a space gun is in [[Jules Verne]]'s novel, ''[[From the Earth to the Moon]]'' (made into a silent movie called ''[[Le Voyage dans la Lune]]''), in which astronauts fly to the moon aboard a ship launched from a cannon. Another famous example is the hydrogen accelerator cannon used by the [[Martian (War of the Worlds)|Martians]] to launch their invasion in [[H. G. Wells]]' book ''[[The War of the Worlds]]''. Wells also used the concept in the climax of the 1936 movie ''[[Things to Come]]''. The device was featured in films as late as 1967, such as ''[[Jules Verne's Rocket to the Moon]]''.
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| In the video game ''[[Ultima: Worlds of Adventure 2: Martian Dreams]]'', [[Percival Lowell]] builds a space gun to send a ship to [[Mars]].
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| [[Gerald Bull]]'s assassination and the [[Project Babylon]] gun were also the starting point for [[Frederick Forsyth]]'s 1994 novel ''[[The Fist of God]]''.
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| ==See also==
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| {{Portal| Spaceflight }}
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| * [[Newton's cannonball]]
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| * [[Super High Altitude Research Project|SHARP]]
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| * [[Quicklaunch]]
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| * [[StarTram]]
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| * [[Space elevator]]
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| * [[Launch loop]]
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| * [[Lightcraft]]
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| * [[Space fountain]]
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| * [[Tether propulsion]]
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| * [[Non-rocket spacelaunch]]
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| ==References==
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| {{Reflist}}
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| ==External links==
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| * [http://www.fas.org/news/iraq/1998/05/980500-bull.htm FAS space gun page]
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| * [http://nextbigfuture.com/2010/03/150-kiloton-nuclear-verne-gun.html The 150 Kiloton Nuclear Verne Gun]
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| {{Non-rocket spacelaunch}}
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| {{DEFAULTSORT:Space Gun}}
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| [[Category:Space guns| ]]
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| [[Category:Megastructures]]
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| [[Category:Spacecraft propulsion]]
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| [[Category:Spaceflight technologies]]
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| [[Category:Vertical transport devices]]
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| [[Category:Space access]]
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Greetings! I am Myrtle Shroyer. Years in the past we moved to North Dakota. Hiring is her working day job now but she's usually wanted her personal business. To do aerobics is a factor that I'm totally addicted to.
my web blog; meal delivery service