From Halopedia, the Halo wiki
Anvil Station, sometimes written as ANVIL Station, is a secret UNSC space station in orbit over an unknown planet. The Spartan-IVs and Swords of Sanghelios Sangheili warriors use the station to run War Games exercises in which they hone their combat skills and test experimental technology.
Crew and complement
Anvil Station is defended by dedicated squadrons of interceptors, with their pilots sporting the AVIATOR Mjolnir. The station has an additional internal security detail, with Spartans attached to these units noted to prefer the AIR ASSAULT armor. A number of Swords of Sanghelios personnel are additionally attached to the station as part of the ANVIL project, with Sangheili pilots conducting cross-training exercises with their Spartan counterparts. Some of these exercises include the operation of Banshees.
The station has seen the oversight and testing of the following MJOLNIR suits;
UNSC and Sword of Sangheilios partnership
Anvil Station is the result of a classified partnership between the UNSC and Swords of Sanghelios, retrofit to support the newly-established Anvil Initiative and Project CRUCIBLE. Anvil Station was designed for the UNSC to test skunkworks technologies clandestine prototypes, some destined for full and successful production runs, other merely serving as a stop-gap in the development pipeline of Mjolnir components, weapon advancements, and more. Additionally, the station proved home to combat test simulations for both Spartan and Sangheili troops, hoping to test technologies and hone their combat skills.
Non-canon and dubious canon appearances
Built by the UNSC, Anvil Station was created for the Spartan-IV program for use in training human and Sangheili forces. The station consists of a large, cylindrical mid-structure featuring a command center on top. The structure is surrounded by two disk-shaped facilities, with the upper one consisting of several decks used for simulation training, and the lower one comprising of living quarters. At the lower end of the station are docking ports for transport modules. The station has a projected operational life of 250 years and in total there are 7,365 humans and Sangheili working on-board.
On January 28, 2552, the designs for the station were approved. As early as 2553, the ANVIL initiative saw a number of very select joint training engagements between Spartan-IVs and Swords of Sanghelios Sangheili.
During development, Anvil Station was referred to as "Crucible Station".
The Anvil Station was the setting for the cancelled Halo Online game. After the game's cancellation, both the station and the Anvil Initiative have been mentioned in ancillary media, such as Halo: Official Spartan Field Manual. With the arrival of Season 5: Anvil on Halo: The Master Chief Collection, the Anvil Station was mentioned for the first time as the testing ground of several new armors added into Halo 3's armor customization and the namesake of the aforementioned Season.
List of appearances