Editing Mass driver

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[[File:HReach-OnagerMDC.png|thumb|300px|An [[Mark 2488 Magnetic Accelerator Cannon|Onager]] mass driver.]]
The '''mass driver''' is a [[United Nations Space Command]] weapons system and orbital launch assembly.<ref name="contact">'''Halo: Contact Harvest''', ''pages 117-118''</ref><ref name="reach">'''Halo: Reach''', campaign level ''[[The Pillar of Autumn (Halo: Reach level)|The Pillar of Autumn]]''</ref> The operating principle of the mass driver is essentially the same as that of the [[Magnetic Accelerator Cannon]]: a [[Wikipedia:Coilgun|coilgun]] that magnetically accelerates a package consisting of a magnetizable holder containing a payload.

==Description==
A mass driver, or "electromagnetic catapult", is a space-launch method that uses a [[Wikipedia:Linear motor|linear motor]] to accelerate payloads to extremely high speeds. All existing and contemplated mass drivers use coils of wire energized by electricity to make electromagnets. Sequential firing of a row of electromagnets accelerates the payload along a path. After leaving the barrel, the payload continues to travel due to inertia. Once the payload has been accelerated, the two separate, and the holder is slowed and cycled for another payload.

Mass drivers consist of flexible "gimbal" assemblies that are linked with magnetic induction devices. They can be loaded with payloads of limited weight, and by means of magnetic induction, mass drivers can propel low-weight payloads into orbit, i.e. easy disposal of hazardous nuclear waste. Mass drivers were used in developing colonies such as [[Harvest]] for orbital lifting, but their capacity for loads of limited mass eventually forced colony worlds to resort to more robust mechanisms for lifting.

The magnetic induction technology of the mass driver was later applied to a whole field of magnetically operated UNSC projectile weaponry, such as the Magnetic Accelerator Cannon and the [[M68 Asynchronous Linear-Induction Motor]].

==Usage==
[[File:H4-MP-Longbow-MAC-02.jpg|thumb|230px|left|A ground-based mass driver station on Concord. Note the device's closer resemblance to a [[railgun]] than to a coilgun.]]
The mass driver on Harvest was originally used for firing nuclear waste into [[Epsilon Indi]], Harvest's sun, and also used during solstice celebrations on Harvest.<ref name="contact"/> Additionally, it could be used as an impromptu weapon, as demonstrated in the [[First Battle of Harvest]]; its magnetic induction technology could be used to propel projectiles at extremely high speeds with a high degree of accuracy, even going so far as to disable the Covenant ship ''[[Rapid Conversion]]'' in two well-placed shots. Later in the battle, the UNSC [[Planetary Security Intelligence]] [[Loki]] used a mass driver to destroy Harvest's orbital facility, the ''[[Tiara]]''.

Sometime after the colonization of Harvest, the shipping operations [[Artificial intelligence|AI]] [[Sif]] had a critical failure in her data center's power supply. Trying to be as helpful as possible, another AI, [[Mack]], used the mass driver to boost the component into orbit - literally shooting the power supply into the ''Tiara''<nowiki>'</nowiki>s coupling station.<ref name="contact"/> This was a very risky move, seeing as Mack could have easily destroyed Sif's main data center, effectively "killing" her.

[[Longbow Station]] in the northern polar region of [[Concord]] had a number of channel-based mass drivers, used by the [[Unified Earth Government]] to deliver deep-space monitoring relays to study remote star systems before the [[Human-Covenant War]]. At least one of Concord's mass drivers appeared to be based on [[railgun]] technology, as opposed to the coilgun technology used by other known mass drivers.<ref>'''Halo 4''', multiplayer map ''[[Longbow]]'' description</ref>

[[The Rubble]] possessed two mass drivers which were used to break up larger [[asteroid]]s to make mining them easier. They were later used to disable the {{UNSCShip|Midsummer Night}}, but were later destroyed by the Covenant ship ''[[Infinite Spoils]]''.<ref name="CP">'''Halo: The Cole Protocol''', ''page ??''</ref>

During the [[Siege of New Alexandria]] in the [[Fall of Reach]], [[New Alexandria|the city's]] mass driver was used to unsuccessfully stop an approaching {{Class|SDV|heavy corvette}} within "danger close" range.<ref>'''Halo: Reach''', campaign level ''[[Exodus]]''</ref> On the last day of the invasion, [[Emile-A239]] manned an [[Mark 2488 Magnetic Accelerator Cannon|Mark 2488 Onager]] mass driver to fend off Covenant forces assaulting the {{UNSCShip|Pillar of Autumn}} at the [[Aszod ship breaking yards]].<ref name="reach"/> However, Emile was killed by two [[Sangheili]] warriors, prompting [[SPARTAN-B312]] to commandeer the cannon and destroy an incoming {{Class|CCS|battlecruiser}} in order to allow the ''Autumn'' to escape.<ref name="reach"/>

During the [[Raid on Ivanoff Station]] in the summer of [[2557]], several mass drivers were used to defend the [[Composer]] from invading [[Covenant remnant]] forces under the auspices of the [[Ur-Didact|Didact]] and his ship, the ''[[Mantle's Approach]]''. Ultimately, they failed to prevent him from acquiring the Composer.<ref>'''Halo 4''', campaign level ''[[Composer (level)|Composer]]''</ref>
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==Gallery==
<gallery>
File:Onager.jpg|The Onager installed in the Aszod ship breaking yards.
File:Onager charging.jpg|A mass driver's magnetic coils charging.
File:HaloReach - MACrusher.jpg|SPARTAN-B312 firing a mass driver at an incoming ''CCS''-class battlecruiser.
</gallery>

==List of appearances==
*''[[Halo: Contact Harvest]]'' {{1st}}
*''[[Halo: The Cole Protocol]]''
*''[[Halo: Reach]]''
*''[[Halo 4]]''

==Sources==
<references/>
[[Category:Magnetic acceleration weapons]]