Jovian Moons

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There is more information available on this subject at Jovian Moons on the English Wikipedia.

The Jovian Moons[1][2][3] or Jovian colonies[4] are the natural satellites orbiting the gas giant Jupiter in the Sol system. Some of the moons have been colonized by humanity.[1][5][6] The Jovian Moons contain a number of strong, growing population centers with centuries of history.[3]


Satellite system[edit]

  • Europa - The only known fully terraformed Jovian moon. It features a frosty atmosphere. Although scientists had theorized that it might already contain oceans beneath the surface with amino acids and the building blocks of life, the first colonists found that this was not the case. Colonization occurred without the discovery of any new life forms.[5][6]
  • Io - Despite being massively volcanic and atmospherically volatile, Io supports a large colony of humans.[5][6]
  • Ganymede - The largest Jovian Moon and in the Sol System, bigger than both Luna and Mercury. It has been partially terraformed, though supposedly retains a harsh climate. Ganymede is well-populated.[5][6]
  • Callisto - With little civilian population to speak of, Callisto's purpose is primarily militaristic in nature; the moon's several bases are capable of launching their units and ships within an hour's notice.[5][6]


Colonization and early strife[edit]

Earth's national governments had established joint efforts to colonize the moons, along with several other bodies in the Sol system, by 2080.[1] In the mid-22nd century, before the formation of the UNSC, unrest began brewing on the moons as various Unified German Republic corporations based there became targets for attacks perpetrated by neo-communist Koslovics. As a result of an increasing anti-Koslovic sentiment, a resurgent fascist movement known as the Frieden arose on the Jovian Moons. Supported by Unified German Republic corporations, the Frieden opposed both the Koslovics and the United Nations' influence, seeking to achieve peace by destroying the "oppressors on Terra Firma".[7]

In 2160, the Frieden attacked the UN Colonial Advisers on Io, sparking a three-month conflict known as the Jovian Moons Campaign, followed by more conflicts across the Sol system, including the Rain Forest Wars, a series of clashes of Mars, and the Interplanetary War. The Frieden and the Koslovics were eventually defeated, and the moons were transferred to the control of the United Nations.[7]

In 2170, Callisto was the site of the signing of the Callisto Treaty which officially ended the Interplanetary War.[2][3]

Human-Covenant war[edit]

"Another whisper, sir, near Io. We have probes en route."

Moments before the Battle of Earth during the Human-Covenant War, the Prophet of Regret's Fleet of Sacred Consecration was detected near Io by Io Station.[8][9] Numerous habitats in the Jovian Moons survived the Covenant assault largely unscathed.[10] Europa, specifically, did not suffer when the Covenant attacked.[5][6] After 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 that were left in ruins following the siege on the Sol system.[11]


After the New Phoenix Incident in July 2557, the former captain of the UNSC Infinity, Andrew Del Rio, utilized his connections and accumulated favors to begin an obscure, though rewarding, political career on one of the Jovian moons and eventually replaced a deceased senator of the Unified Earth Government Senate.[4]


"Jovian" is the adjective form of "Jove", who was the god representing Jupiter in the sky.

List of appearances[edit]


  1. ^ a b c Halo Mythos - Rise of Humanity, page 46-47
  2. ^ a b Halo Encyclopedia (2011 edition) - Timeline: 1969 CE-2492 CE, page 32-33
  3. ^ a b c Halo Encyclopedia (2022 edition), page 40-41
  4. ^ a b Halo Waypoint, Andrew Del Rio (Retrieved on Jun 1, 2020) [archive]
  5. ^ a b c d e f Halo Encyclopedia (2009 edition) - Locations: The Sol System, page 282-283
  6. ^ a b c d e f Halo Encyclopedia (2011 edition) - Locations: The Sol System, page 294-295
  7. ^ a b, Halo Storyline: (Additional copy on HBO Forums) (Retrieved on Apr 24, 2008) [local archive] [external archive]
  8. ^ a b Halo 2, campaign level Cairo Station
  9. ^ Halo 2: Anniversary, Terminal 15 - Unyielding
  10. ^ Halo Waypoint, Universe - Humans (Retrieved on Jun 1, 2020) [archive]
  11. ^ Halo Waypoint, Tribute (Retrieved on Jun 1, 2020) [archive]