From Halopedia, the Halo wiki

There is more information available on this subject at Mars on the English Wikipedia.
An illustration of Mars.


Sol system[1][2][3]



Orbital position:

Fourth planet[1][2][3]


Two; Phobos, Deimos[1]



6,792 kilometres (4,220 mi)[1]


0.376 G[1]

Length of day:

24 hours, 39 minutes, 35 seconds[1]

Length of year:

668.6 days[1]


0.7 (CO2, N2, O2)[1]

Surface temperature:

-84°C to 26°C (-120°F to 80°F)[1]



Martian,[1] Marsman (rare)[4]







"Time on Mars tends to give a man... perspective."
Edward Buck, referring to Taylor H. Miles.[5]

Mars, also known as Sol IV,[6] known as Edom in the Forerunner era,[7] is the fourth planet of the Sol system, and one of four terrestrial worlds. One of the first human interplanetary colonies,[8] Mars is a major industrial center and one of the largest in the Sol system.[1] Mars is home to the UNSC Navy's primary shipyards[9] and the Orbital Drop Shock Troopers' headquarters in the city of Kenosha, Tanais.[1]



Terraforming has transformed the surface of Mars from a former barren and uninhabitable environment into an Earth-like world.[10] This process took centuries.[2][3]


Forerunner locations[edit]
Orbital installations[edit]
Mars from orbit.
Mars, as viewed from orbit.

Known residents[edit]




Ancient history[edit]

Circa 97,445 BCE, ten thousand years after the human-Forerunner wars, Forerunner Miners worked on Mars. Bornstellar Makes Eternal Lasting was sent to work into a step family of Miners as punishment for his rebellious ways. Inspired by his ancilla's tales of Precursor treasure, Bornstellar eventually escaped and made his way to Earth aboard an automated transport. During his stay on Mars, Bornstellar climbed the planet's highest volcano, Olympus Mons.[7]

Following the firing of the Halo Array, an automated Juridical listening post remained hidden on Mars for over a hundred millennia.[11]

Rise of humanity[edit]

In 2080, Mars was the first planet colonized by humanity[1] in the first wave of interplanetary colonization in the late 21st century.[12] Following its colonization—largely driven by corporations eager to break free from the restrictions of Earth's gravity and international law—Mars quickly became a hub of industry and state-of-the-art scientific research. Advancements were made particularly in the areas of nano- and biotechnologies; largely robotics-driven industrial manufacturing and spacecraft construction flourished, the latter most notably in the Argyre Planitia.[8] Even before the planet was terraformed, Mars was one of the largest industrial hubs in the Sol system.[1] With the advances in terraforming technology that accompanied this boom of technological development, Mars was transformed into a planet with near-Earth conditions, becoming home to many.[8] During the 22nd century, an unidentified man from Mars led a failed habitat-ship project, ultimately taking the funds collected from prospective passengers and fleeing to the Amazon of South America, Earth. There, he lived among the Khabnathwa people—the last uncontacted culture on the planet—and convinced them that he was their god-king, eventually destroying their culture.[4]

Interplanetary War[edit]

Main article: Mars Campaign

During the Interplanetary War, Mars became the first colony to rebel from Earth's control. During the events that led up to the war, Mars was home to numerous activists and anti-Earth insurgents. When the first shots of the war were fired, many Martians aligned themselves with the neo-communist Koslovics.[1]

Mars was the site of a decisive battle during the events surrounding the formation of the United Nations Space Command. The Koslovics attempted to seize control of the shipbuilding plants in the Argyre Planitia, but were repelled by a series of blitzkrieg attacks by the newly-organized UNSC Marines in a series of brutal battles in 2163. This victory marked a significant boost in the morale of the United Nations forces, and the nascent UNSC subsequently moved on to destroy the Koslovic and Frieden movements throughout the Solar System.[8] After the war ended in 2170 with the signing of the Callisto Treaty, remaining rebels on Mars were put down in a series of harsh crackdowns on the planet.[1]

Peace under the UEG[edit]

The AMG Transport Dynamics Z-12 prototype vehicle quickly made a name for itself around 2319 by being showcased in the unpopulated areas of Mars.[13]

At some point before or during the Insurrection, John Forge was in the Military police on Mars.[14]

Human-Covenant War[edit]

Main article: Human-Covenant War

On January 18, 2524, a telescope located on or orbiting Mars spotted an anomalous, evidently artificial object while observing the stellar cluster NGC 2244; while unknown to humans at the time, this was actually the Covenant planetoid station High Charity.[15][Note 1]

On April 2, 2526, UNSC forces working with ONI agents prevented an attack on New Harmony. Two Insurrectionists, Christina Rice and James McCann, were disguised as Army specialists and were stealing nuclear weapons for a possible attack.[16]

During the war, refugees were housed on Mars.[17] Throughout the war, the UEG kept plans for an evacuation of industrial facilities away from Mars and Earth, which were eventually put into action following the Fall of Reach and the believed compromised location of the human homeworld.[18]

During the Covenant's assault in the Sol system in late 2552, Mars was attacked particularly hard along with Luna[19] following the arrival of the High Prophet of Truth's fleet.[1] Though Mars and Luna still fared better than Earth.[19] While the UNSC resistance was crushed, many human population centers on Mars survived the Covenant assault relatively intact and the Martian defense on the planet is credited for delaying Covenant forces from pressing their invasion on Earth.[20][1] One such engagement was set on the fields of Mare Erythraeum. There, Colonel James Ackerson and his UNSC Army forces combated against the Fleet of Furious Redemption's ground forces, commanded by Jiralhanae Chieftain Lepidus. The UNSC lost the battle and Ackerson was taken prisoner.[21] 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.[22]

On November 18, 2552, at 15:45 pm, High Charity arrived near Mars and made a Slipspace jump to Installation 00. This event was recorded by the local Juridical terminal.[11]


After the Human-Covenant War, an ONI surgical and research facility and a UNSC Spartan base were established on Mars, which augmented and housed the SPARTAN-IV supersoldiers.[23][24] As the UNSC continued to rebuild in the years following the war, the orbital shipyards located on and around Mars remained its primary shipyards.[9] In 2555, Mars played host to a joint-operations training exercise, Operation: FOCUS LENS 2555 - tasked with simulating a second Covenant invasion of Sol system.[25]

At some point after 2556, Black-Box manipulated UNSC accounting to show that a cabin was built on Mars. In reality, it was built on Rossbach's World.[26]

Following The Reclamation in October 2558, Mars was under the control of the Created, broadcasting their signals.[26]

Government and society[edit]


Martians produce a type of Whiskey, one that is enjoyed by Michael Stanforth.[27] Misriah Armory, the largest military weapons and equipment manufacturer in human history, is based on Mars.[28] The planet is also home to Martian Metals Shipyards, a spacecraft construction company[29] with Aerofabrique SA also maintaining a presence in these shipyards.[30] Acheron Security also maintained a facility on Mars.[31] A boutique firm of extreme sporting enthusiasts developed the Envy VISR, though they did not share it with the UNSC immediately due to their anti-military stance.[32]

Help.png This section needs expansion. You can help Halopedia by expanding it.


Olympus Mons has been made suitable for snowboarding, with one Marine suggesting that they rode it during their youth.[33] Bobsledding is also a well-renowned sport on Mars, conducted inside sealed habitats on the planet as part of the Martian Olympics.[34]

Help.png This section needs expansion. You can help Halopedia by expanding it.


Halo: Combat Evolved[edit]

Main article: Halo: Combat Evolved

One multiplayer map in Halo: Combat Evolved takes place in orbit of Mars, Chiron TL-34.


  • Despite being terraformed, the planet is still depicted as having a red-orange color when seen from space in Halo: Uprising. The Halo Encyclopedia (2009 edition) contradicts this, saying that Mars is now "as blue and green as Earth."
  • Edom is the Hebrew word for Red, and the name of an ancient Semitic Kingdom.


List of appearances[edit]


  1. ^ NGC 2244 is 5200 light-years away from Sol, meaning that the light from the cluster would have taken 5200 years to reach the telescope. High Charity was commissioned in 648 BCE, which implies that the holy city must have been significantly closer to Sol than NGC 2244, which the telescope was observing. This is also apparent by High Charity's silhouette being recognizable from the image, as it would otherwise be impossible to discern on the scale involved.


  1. ^ a b c d e f g h i j k l m n o p q r s t Halo Waypoint - Universe, Locations, Mars (Retrieved on Jan 19, 2021) [local archive] [external archive]
  2. ^ a b c d Halo Encyclopedia (2009 edition) - The Sol System, page 282-283
  3. ^ a b c d Halo Encyclopedia (2011 edition) - The Sol System, page 294-295
  4. ^ a b Halo: Outcasts, chapter 17
  5. ^ Halo 3: ODST, ViDoc, Desperate Measures
  6. ^ Halo Channel: Encyclopedia
  7. ^ a b Halo: Cryptum, chapter 1
  8. ^ a b c d Halo Encyclopedia (2011 edition), page 42
  9. ^ a b Halo Waypoint, Canon Fodder - Have S'moa (Retrieved on Mar 16, 2021) [archive]
  10. ^ Halo: Arms Race
  11. ^ a b Halo Waypoint Forums, Query: Catalog(old) (Retrieved on Dec 29, 2019) [local archive] [external archive]
  12. ^ Halo Encyclopedia (2009 edition), page 44
  13. ^ Halo Waypoint, Universe - Warthog (Retrieved on Jun 1, 2020) [archive]
  14. ^ Halo Wars: Official Strategy Guide - Factions: UNSC Leaders, Spirit of Bloody Fire. Cutter. Bloody hell., page 22-23
  15. ^ Dr. Halsey's personal journal, "A new threat?" image
  16. ^ Halo 4: Forward Unto Dawn, episode 1
  17. ^ Halo: Fractures - Oasis
  18. ^, Jason Jones Interviewed By You (Archive)
  19. ^ a b Halo: New Blood, chapter 12
  20. ^ Halo Waypoint, Humans (Retrieved on Jun 1, 2020) [archive]
  21. ^ Halo: Uprising, issue 1
  22. ^ Halo Waypoint, Tribute (Retrieved on Jun 1, 2020) [archive]
  23. ^ Halo: New Blood, chapter 14
  24. ^ Halo: New Blood, chapter 18
  25. ^ Halo 5: Guardians Limited Edition, Dossier files - Holly Tanaka
  26. ^ a b Halo: Fractures, Rossbach's World
  27. ^ Halo: Fleet Battles - Fall of Reach Campaign Guide, page 29
  28. ^ Halo Waypoint - Canon Fodder: Outpost Discoveries
  29. ^ Halo Waypoint, Canon Fodder - Shippin' Out (Retrieved on Feb 2, 2022) [archive]
  30. ^ Halo: Warfleet, page 38-39
  31. ^ Halo 4: The Essential Visual Guide, page 148
  32. ^ Halo 5: Guardians: Envy VISR description
  33. ^, Type-51 Carbine (Retrieved on Jun 1, 2020) [archive]
  34. ^ Halo: Shadows of Reach, chapter 4