Callisto, also Jupiter IV, is the second-largest moon of Jupiter and the third-largest in the Sol system. It houses the MCRN Callisto Shipyards, the MCR's primary military shipyards.

History[edit | edit source]

The moon has a moderate subterranean population as the moon does not enjoy the protection from Jupiter's radiation belts in contrast to Ganymede. The colony has a mining industry but also boasts shipyards, including the MCRN Callisto shipyards and the United Nations (UN) owned UN Callisto shipyards[1]. Additionally, a respected university with affiliations to Mars's technical institutes is located in the colony. The hemisphere facing Jupiter includes an observatory focused on Jovian research[2].

Events[edit | edit source]

At some point prior to the Eros Incident, Callisto was the site of a proxy war between Earth and Mars, the Callisto Insurrection. As tensions rose over union negotiations, the UN sent in increasing numbers of private security forces while the Martian Congressional Republic (MCR) sent in advisors. The groups inflamed the tensions, resulting in Belter groups they backed fighting each other in the stead of Earth and Mars[3]. This lead to the death of Charanpal Avasarala, the son of UN Secretary-General Chrisjen Avasarala.

A little more than a year before the Free Navy Conflict [4], the Free Navy attacks the MCRN shipyard in a covert operation. The operation manages to secure stealth tech – 4, thousand-litre canisters of MCRN energy-absorbing coating. The heist is covered up by the destruction of the shipyard by kinetic impacts of pre-accelerated meteors[5].

The impacts were sizable to result in civilian casualties and destruction of colony infrastructure. This includes the cracking and depressurization of at least one of the colony's hard shelters[6].

Callisto was also a location prominent in the Free Navy Conflict. Like many of the outer planets, it embraced control of the Free Navy, as seen in the adoption of Free Navy script as a valid currency[2].

In the latter portions of the war, it was the de facto command center of the Free Navy following the Pella coming into port for repairs. Due to this, the Jovian System saw two large battles, one of which was fought in the vicinity of Callisto's orbit (see the Battle of Callisto). The Free Navy lost several ships but ultimate secured a victory over Micah al-Dujaili's wing of the Consolidated Fleet[7]. Callisto remained the de facto command center of the Free Navy until the departure of Marco Inaros and the Pella to reinforce the Free Navy in the Battle of Medina Station[6].

Media[edit | edit source]

Notes[edit | edit source]

Trivia[edit | edit source]

  • Callisto's namesake is from Greek mythology: a nymph in retinue to the goddess Artemis and one of Zeus's (Roman: Jupiter) consorts. See also Callisto_(mythology) on Wikipedia.
  • The moon is suspected to house a subterranean ocean, and a possible location for life outside of Earth, not unlike Europa. This topic has not been discussed by the novels but, due to the protomolecule being the first evidence of extraterrestrial life, either humans have not yet reached the ocean, the ocean does not contain living organisms, or the ocean has not been imagined to exist in the novels.
  • Callisto is the most heavily cratered object planet in the entire Sol system.
  • At a diameter of 4,820.6 km, Callisto is only 58 km bigger than the innermost planet of Mercury.
  • It is the outermost of the Galilean moons.
  • Callisto is more than 40%+ ice, with the remaining elements being rock.
  • It has the least mass of the Galilean moons, despite being the second biggest moon of Jupiter.


  1. The Expanse Novel Nemesis Games - Prologue: Filip
  2. 2.0 2.1 The Expanse Novel Babylon's Ashes - Chapter 36: Filip
  3. The Expanse Novel Babylon's Ashes - Chapter 21: Jakulski
  4. The Expanse Novel Babylon's Ashes - Chapter 1: Pa
  5. The Expanse Novel Nemesis Games - Prologue: Filip
  6. 6.0 6.1 The Expanse Novel Babylon's Ashes - Chapter 47: Filip
  7. The Expanse Novel Babylon's Ashes - Chapter 42: Marco

External links[edit | edit source]

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