Military Assault Command Operations
Military Assault Command Operations (commonly abbreviated as "MACO", pronounced "MAY-ko") was a United Earth organization that existed as a part of the United Earth Military during the 2150s, prior to the founding of the Federation. The MACOs were not associated with Starfleet. As of 2153, MACO tactics and technology were two to three years more advanced than those of Starfleet, but their combat expertise was initially limited to simulations conducted on Earth. (; )

The military officer who oversaw the MACOs was General . () MACO posts included Atlanta, Georgia and the Janus loop. Training posts included West Point in New York, as well as Jupiter Station for zero gravity/rifle training, and Luna for survival training. ()

A detachment of troops commanded by Major J. Hayes was assigned to the Starfleet vessel  for a mission into the Delphic Expanse in 2153. Admiral Maxwell Forrest was surprised that Captain Jonathan Archer had requested military officers aboard his ship. () When the MACOs first came aboard Enterprise, they certainly felt like outsiders, tasked to integrate with the ship's Starfleet contingent. () The MACOs saw their first action six weeks into the mission; in September, Hayes and a six-man team rescued Archer, Commander Tucker, and Kessick from the clutches of a trellium mining planet. () By the end of their time in the Delphic Expanse, none of the MACOs aboard Enterprise felt like outsiders anymore. ()

Following the foundation of the United Federation of Planets, the organization was disbanded, with personnel being offered Federation Starfleet commissions on a discretionary basis and possibly offered commissions in other agencies in the Federation. The Federation Starfleet, just as with its United Earth predecessor, continued to distance itself from the notion of being a military organization, causing deep conflict for at least one former MACO who donned a . ()

Combat timeline

2153 September 
 Rescuing Captain Archer and Commander Tucker from a Trellium mining planet ()
 Trying to fend off an Osaarian boarding party ()
 Battling on the Loque'eque homeworld ()
 Trying to fend off a Xindi-Reptilian boarding party ()
 Providing escort for Enterprise officers on the Seleya ()

2153 October 
 Providing escort for Enterprise officers on the Xindi-Arboreal colony ()
 Providing backup on a Human colony in the Expanse ()

2153 November 
 Taking back Enterprise from Triannon hijackers ()

2153 December 
 Guarding the prisoner Degra ()
 Providing combat training for Enterprise officers ()
 Containing a Sphere-Builder test subject ()

2154 January 
 Assisting Captain Archer in a possible mutiny situation ()

2154 February 
 Raiding an Illyrian vessel ()
 Providing escort for Enterprise officers inside a Delphic Expanse sphere ()
 Recovering Ensign Hoshi Sato from a Reptilian vessel ()
 Assisting in destroying the Xindi weapon ()
 Repelling a Sphere-Builder boarding party ()
 Accompanying Archer to a meeting with Vosk on 1944 Earth ()

2154 May 
 Escort and guard for the prisoner Arik Soong ()
 Attempt to fend off an Augment boarding party ()
 Attempting to take back Cold Station 12 from the Augments ()

2154 November 
 Escort and guard of Tellarite delegation ()
 Boarding the Romulan drone ship ()
 Attempting to fend off a Klingon Augment boarding party ()

2154 December 
 Escort of Lt. Malcolm Reed ()

2156 to 2160
 MACOs participate in the Earth-Romulan War ()

2161 (October) 
 Ambush of kidnappers on Rigel X, just prior to the formal treaty signing that created the United Federation of Planets ()

Appendices

Related topics 
 MACO personnel
 MACO ranks
 MACO uniform and equipment

Appearances 
 (Season 3)

 (Season 4)

Background information 
The MACO Enterprise mission patch depicted a  shark. ( text commentary, ENT Season 3 DVD) The mission patch was designed by Scenic Art Supervisor Michael Okuda. (Star Trek: Costumes: Five Decades of Fashion from the Final Frontier, p. 217)

The patch was later used during the production of , modified to feature the name of the  rather than Enterprise. The MACO patch was stenciled on the sides of PX70 motorcycles used in the film  and was printed onto T-shirts given to the cast and crew. 

Regarding the disbanding of MACO, Star Trek Beyond co-writer Doug Jung once noted, "I thought it'd be kind of interesting [….] You can make some modern analogies in terms of like the CIA, which is – you're asking these people, you're training them their whole lives to see the world one way, and then you say, 'Oh, by the way, you're now obsolete, but we'd like you to do [this other thing].' It's tough."

Apocrypha 
The ization of  states that Captain Archer was initially uncomfortable with the notion of military personnel serving aboard Enterprise but reconciled himself to the idea, given that it seemed as if the MACOs would be beneficial to the search for the Xindi weapon. The same novelization also suggests that MACO be pronounced "Mah-co" rather than "May-co", despite the latter being the commonly used canon pronunciation.

In the Romulan War Pocket ENT novel Beneath the Raptor's Wing, the "O" in MACO stands for "organization" instead of "operations", making the MACOs' proper title "Military Assault Command Organization".

According to the novel The Needs of the Many, MACOs continued to exist into the 25th century.

In Star Trek Online, the MACOs are an internal branch of Starfleet focused on infantry and ground combat operations. MACO personnel use standard, naval-derived Starfleet ranking structure,rather than the army/marine style. They first appear in-game alongside the Klingon Honor Guard as part of Task Force Omega, a specialized cross-faction unit formed to fight the resurgent Borg Collective, and MACO-affiliated characters appear in other ground-based tactical scenarios further into the story, usually in sections featuring combat against enemies such as the Voth, Vaadwaur, and Tzenkethi. Starfleet-aligned player characters can obtain specialized MACO armor and weaponry, as well as cosmetic player titles such as "MACO Commander", implying that MACO membership is more of a subclass of Starfleet officer than an independent organization.

External link 
 

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ja:軍事攻撃指令作戦部隊
Earth agencies
Earth military organizations