From Halopedia, the Halo wiki
Luna, often referred to as the Moon, is the only natural satellite of Earth. Luna is home to a large human population and the renowned Luna OCS Academy. Luna houses a number of skyhook defense complexes suspended in its low orbit.
Luna has a barren surface and is atmospherically devoid. It's gravity is low, which has prevented large scale terraforming. Day and night run in a month long pattern of two weeks of darkness and two weeks of light.
Luna has a "near side"/"front face" and a "far side". The far side of Luna faces out into space while the near side faces Earth. The far side contains more and deeper impact craters than the near side since the near side is protected by Earth itself. Daedalus Crater was in the middle of the far side while Mare Cognitum is on the near side and visible from Earth without a telescope.
Due to being atmospherically devoid, the habitats on Luna are sealed from vacuum and interconnected by tubes. Most contain soaring spires dotted with windows (all designed to take advantage of the low gravity) and vast dome habitats. Colonies on the moon are sometimes referred to as canopy settlements.
Rise of humanity
By 2492, a governing body of Luna was known as Luna Confederated States, the State of Mare Nubium being one of the said states. The Academy at Mare Nubium, known more generally as the Luna OCS Academy, was located here.
Despite its proximity to Earth, Luna was home to some degree of Insurrectionist activity; shortly after 2530, the parents of Michael Crespo died attempting to detonate a bomb attached to a government building on Luna.
During the Battle of Earth in late 2552, Luna's skyhook defense complexes came under attack by the Covenant and were defended by ONI Security personnel. Other Covenant forces attacked Luna's cities to ensure that the UNSC would not be able to launch a sneak attack from their Lunar military bases. Both Luna and Mars got hit particularly hard compared to other colonies in the Sol system, although they both fared better than Earth. Around November 17, an overwhelming and final Covenant naval forces under the command of the Prophet of Truth break through the Lunar perimeter and later overrun too much of the weakened Home Fleet over Earth as the Truth-controlled Forerunner Dreadnought headed for the planet, letting the Covenant fleet to lead a subsequent bombardment on the human homeworld.
Many habitats on the moon survived the Covenant assault relatively intact. Following the Battle for Tribute with the loss of over half of the population on Tribute, Earth was unable to afford to spare any immediate assistance with Sol’s colonies left in ruins.
Following the Human-Covenant War, Luna was home to the Office of Naval Intelligence vessel UNSC Rubicon, which was deployed to Installation 00 in December of 2553 to investigate the disappearance of automated probes sent eight months prior and to determine the source of an unknown signal.
Luna lost power during The Reclamation. Two days later, one of the facilities on the moon was overrun by Armigers who took hostages. Shortly after, Alpha-Nine arrived on a mission in order to retrieve Vergil.
Government and society
Due to the physical limitations of the moon, gravity and atmospherics have to be provided by large scale system and massive housing infrastructure. Luna features some of the most densely populated places in the galaxy with Mare Cognitum being the largest.
List of appearances