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The MCRN Home Fleet around Mars.

The Martian Congressional Republic Navy (MCRN) is the naval force of the Martian Congressional Republic (MCR), and the most important branch of its military.

Though smaller in size than the United Nations Navy (UNN), it is more technologically advanced and generally considered on par with the UNN.

MCRN logo-onwhite-640x480

Ship construction[]

Most smaller Martian ships are constructed in the same basic configuration, floor by floor from the drive cone and reactors. First is the engine room, then the cargo bay, followed by specialty compartments, then the crew cabins followed by the galley. Next deck is the medical bay. The storage and airlock deck follow, with the command deck and pilot at the “top”. Large(r) ships will have different configuration, with Ops/CIC positioned amidships with particular deck as The Main Deck. Under thrust, Martian ships are essentially skyscrapers, with elevators and ladders connecting the various decks.

MCRN ships generally cruise separately from one another, or in pairs for smaller ships. The third-generation battleships are well armed enough to be considered fleets unto themselves. The pride of the MCRN is centered around the Donnager-class battleships. Donnager-class battleships measure nearly 500 meters long, or the length of a 130-story office building, and bristle with torpedo tubes, point defense cannons, and massive 90 meter long railguns. They serve as flagships for MCRN fleets, and are large enough to carry small Escort Frigates and Patrol Destroyers within them.[1]

Second-generation battleships still have a place in the MCRN, serving alongside fast-attack cruisers, destroyers and frigates capable of patrolling the entire Sol system. Mars also has advanced stealth technology, though battleships and larger ships typically avoid this in favor of the intimidating effect of an aggressive battle posture. Larger ships are basically mobile bases, such as the Donnager-class, carrying marines and military interrogators aided by pharmaceuticals.

By virtue of superior technology, fiercer armament, and superior-trained crew, the battle fleets of Mars are unmatched. Martians never cease to remind others of this, and make their military pride known at any and every opportunity.[2]

Rank structure[]

The Martian Congressional Republic Navy is led by a four-star Admiral.

MCRN known ranks (including Martian Marine Corps MMC)[]

Shipyards and facilities[]

Shipyards/facilities Appears Notes
MCRN Callisto shipyards TV[3] and Books Destroyed by Free Navy asteroid strike. (Books only)
Mariner Valley shipyard TV Destroyed by Free Navy terrorist bombing.
Asteria Naval Base TV War College of the MCRN.
Hecate Base TV and Books Major MCRN base.


The Martian Congressional Republic Navy is divided into three main fleets. Additional fleets operate as a part of the main ones:

Fleets Appears Notes
MCRN Home fleet Books and TV Operates in Mars A.O. and inner Sol System.
MCRN Saturn fleet TV lore Operates in Saturn A.O.
MCRN Jupiter fleet Books and TV Operates in Jupiter A.O. and the Belt.
MCRN 3rd fleet TV Lost four battle groups during combat in the UN-MCR War.

Known ships/Platforms[]

Designation Class Ship type Appears Notes
MCRN Donnager Donnager-class Battleship Leviathan Wakes Scuttled after it was damaged by stealth ships and boarded, all while investigating the Scopuli distress call and Canterbury destruction.
MCRN Bellaire Nemesis Games
MCRN Barkeith Nemesis Games, Babylon's Ashes Stolen from the MCRN by Admiral Duarte's Laconian faction before being destroyed by a Ring Gate anomaly.
MCRN Harman Dae-Jung Caliban's War Transported Bobbie to Earth along with a delegation from Mars
Carcassonne Tiamat's Wrath Mothballed then later dismantled and rebuilt for the Underground.
Armstrong Tiamat's Wrath Mothballed then later dismantled and rebuilt for the Underground.
Bellerophon Tiamat's Wrath Mothballed then later dismantled and rebuilt for the Underground.
MCRN Cydonia Raptor-class Fast-attack cruiser Caliban's War
MCRN Hammurabi Unknown class Frigate Abaddon's Gate One of the first ships to enter the Slow Zone.
MCRN Sally Ride Unknown class Destroyer Caliban's War
MCRN Iani Chaos Unknown class Destroyer Caliban's War Present during Io Campaign.
MCRN Cavalier Unknown class Frigate Abaddon's Gate Present during the Slow zone incident.
MCRN Lucien Unknown class Frigate Abaddon's Gate
MCRN Hijo de puta Unknown class Frigate Abaddon's Gate
MCRN Tachi /
Corvette-class Light frigate All novels Believed to be destroyed, but actually came under the control of the Canterbury crew survivors and recommissioned as Rocinante by the crew themselves.
Pella Nemesis Games, Babylon's Ashes Stolen from the MCRN for the Free Navy. Later destroyed by Ring-Gate anomaly.
Connaught Babylon's Ashes Stolen from MCRN for the Free Navy. Later when crew defected the ship fought alongside the Consolidated Fleet against the Free Navy. Eventually heavily damaged in battle.
MCRN Tsuchi Corvette-class (Presumed) Light frigate Nemesis Games Decommissioned after Io Campaign yet reappeared a year later near Europa.
Shinakuto Babylon's Ashes Stolen from the MCRN for the Free Navy.
Andreas Hofer Nemesis Games
Koto Babylon's Ashes
Solano Babylon's Ashes
Panshin Babylon's Ashes
Serrio Mal Babylon's Ashes
Witch of Endor Babylon's Ashes
Ando Babylon's Ashes
Dagny Taggart Babylon's Ashes
MCRN Bandon Unknown class Unknown ship type Leviathan Wakes Alex Kamal served on the Bandon when he was in service with the MCRN.
MCRN Carson Lei Unknown class Unknown ship type Nemesis Games Destroyed by Free Navy during the raid on Callisto shipyards.
MCRN Apalala Unknown-class Supply ship Nemesis Games Stolen from the MCRN before Free Navy Conflict.

Designation Class Ship type Appears Notes
MCRN Stealth C Ballistic Missile Platform MCRN Stealth C Ballistic Missile Platform Mobile Stealth Missile Platform Season 3 5 were positioned against Earth during the UN-MCR War. All identified platforms were destroyed by the United Nations.
MCRN Donnager Donnager-class Battleship Season 1 Scuttled after it was damaged by Amun-Ra-class Stealth ships and boarded, all while investigating the Scopuli distress call and Canterbury destruction.
MCRN Icaria Planum (TV lore) Became flagship of the MCRN after the destruction of the Donnager. Also current flagship of the MCRN Saturn fleet.
MCRN Schiaparelli (TV lore) Current Flagship of MCRN Jupiter fleet after UN-MCR War.
MCRN Hotspur Season 2 Assigned to MCRN Jupiter fleet, Ganymede border Patrol.
MCRN Firebrand (TV lore) Assigned to MCRN Jupiter fleet, Callisto shipyard defense.
MCRN Sagarmatha Season 5 Part of the EMC ring gate fleet, destroyed during the battle for the Sol gate by the Free Navy.
MCRN Valkyrie Scirocco-class Assault cruiser Season 2 Launched a torpedo at the Weeping Somnambulist.[4]
MCRN Scirocco S2, S3 Destroyed Phoebe Station to prevent UNN Nathan Hale from reaching it. Later damaged during the Ganymede Incident.
MCRN Xuesen Season 3 Sent to the Ring. Bobbie Draper is onboard.
MCRN Hammurabi Season 3 Part of the MCRN Jupiter Fleet headed by Capt. Sandrine Kirino. Witnesses infighting of the UNN Jupiter Fleet after attempted mutiny aboard the UNN Agatha King.
MCRN Aryabhata Season 4 Stolen uniforms of this ship were worn by Belters to enter restricted MCRN facilities.
MCRN Atacama Season 6 Admiral Sandrine Kirino used this ship as her flagship until its destruction
Pella Unknown class Light cruiser Season 5 Stolen from the MCRN for the Free Navy by defected MCRN individuals.
MCRN Morrigan Morrigan-class Patrol destroyer (TV lore) Stationed at Titan.
MCRN Scipio Africanus / Koto Season 1 Season 5 High profile incident in media involving rock-throwing attack, in "Rock Bottom". Later stolen from the MCRN for the Free Navy by MCRN secessionists.
MCRN Cú Chulainn Season 2 Season 4
MCRN Kittur Chennamma Season 3 During the UN-MCR War, the ship was hit by railgun rounds completely destroying its command deck and taking out its water and life support systems. Would later be found by the Rocinante which salvaged its munitions.
MCRN Shandian Season 2 Modified for Stealth operations. Shadowed the UNS Arboghast over Venus until disappearance whilst entering the atmosphere.
MCRN Damascus (TV lore) Part of Operation Silent Wall.
MCRN Iceni (TV lore)
MCRN Avalanche (TV lore)
MCRN Hamill-Stewart (TV lore)
MCRN Ambedkar Season 1 Attempted to Board the Rocinante until receiving MCRN Black Ops code.
MCRN Tanto The Expanse: Dragon Tooth Issue 2 Stolen by Martian defectors, and renamed Camorri Garrista to disguise it as a Belter prospector. During its final engagement the ship had a PDC installed in its airlock to cover a blind spot.
MCRN Kunai The Expanse: Dragon Tooth Issue 4 Stolen by Martian defectors, and believed destroyed fleeing the MCR Parliament bombing. Actually survived remaining hidden until after the Free Navy Conflict.
Serrio Mal Unknown class Heavy frigate Season 5 Stolen from the MCRN for the Free Navy by defected MCRN individuals.
MCRN Tachi /
Corvette-class Light frigate[5] All seasons Believed to be destroyed, but actually came under the control of the Canterbury crew survivors and recommissioned as Rocinante by the crew themselves.
MCRN McCabe (TV lore) Part of Operation Silent Wall.
MCRN Valenza (TV lore)
MCRN Karakum Season 2 Black Ops ship destroyed by United Nations Navy over Ganymede.[6]
MCRN Barkeith D-class Supply ship Season 5 Part of the rogue MCRN fleet, destroyed by the Ring network anomaly during transit to Laconia system.
MCRN Denali Unknown class Unknown ship type Season 6 Located asteroids headed towards Earth alongside UNN Farragut.
MCRN Africanus Unknown class Unknown ship type Season 2 Stationed at Callisto.
MCRN Askia Unknown class Unknown ship type Season 3 C.O. Captain Lucas was onboard Xuesen during the Slow Zone Incident.
MCRN Yangtse Unknown class Unknown ship type Season 1 Launched Ambedkar to Board the Rocinante for inspection.
MCRN R R Martin Unknown class Unknown ship type Season 3 Present at Io Campaign.
MCRN Asander Unknown class Unknown ship type Season 5 Alex Kamal and Admiral Sauveterre both served onboard this ship.

Ship designators/hull numbers[]

Every class of ship in the MCRN has a three alpha character prefix before its ship number. Each letter represents a specific characteristic of the ship, the first letter designates the ship's propulsion method, the second letter designates its role, and the third letter designates its type of ship. For example the MCRN Tachi was designated ECF-270, which indicates an Epstein Drive (E) Combatant (C}, Frigate (F ).[7]


Class Ship type Photo Notes
Donnager-class Battleship RPG Donnagerclass2 The largest and most powerful ship-class in the entire MCRN fleet.
Scirocco-class[8] Assault cruiser RPG Sciroccoclass2
Raptor-class Fast-attack-cruiser RPG Raptorclass2 Considered Top-of-the-line during the UN-MCR War.
Banshee-class[9] Destroyer RPG Bansheeclass2
Morgaina-class[10] Patrol Destroyer RPG Morgainaclass1
Corvette-class[11] Light frigate RPG Corvetteclass2
Unknown class Light frigate A newer class that replaced the Corvette-class. Several were stolen and used by the Free Navy
Asp-class[12] Fast attack craft RPG Aspclass2
Troika-class[13] Dropship RPG Trokiaclass2

Class Ship type Photo Notes
Donnager-class Battleship Donnagerconcept The largest and most powerful ship-class in the entire MCRN fleet.
Scirocco-class Assault cruiser Sciroccoclassconceptart Used to deploy Force Recon Marines via externally docked Chariot-type dropships.
Unknown class Light cruiser PellaConceptship One ship of this class was stolen and used by the Free Navy.
Unknown class Heavy frigate[14] MCRNheavyfrigateconceptartspacedock In service during Free Navy Conflict. At least two were stolen and provided to Free Navy.
Corvette-class Light frigate Mcrncorvetteclassconceptart A capable and well armed light frigate. In service during the cold war between Earth and Mars.
Morrigan-class Patrol destroyer Morriganclassdestroyer1 Heavily used in policing operations across the Sol system.
D-class Supply ship Barkeith concept 1 Armed with PDCs and torpedoes. This class of supply ships was capable of defending itself unlike its UNN equivalents.
Chariot-type Dropship Dropshipskiffconceptart


Eros Incident[]

When the Canterbury was destroyed, and James Holden released his broadcast incriminating the Martian Congressional Republic in its destruction, the MCRN Donnager picked up Holden and his crew of the Knight. During Holden's debrief, the Donnager is attacked by six unidentified ships and is eventually destroyed. Holden and his crew escaped on the MCRN Corvette-class ship Tachi and later claim it as salvage.

When the Donnager is destroyed by what is believed to be OPA ships, Mars declares war on the Asteroid Belt. Later, when Holden releases information that the ships that destroyed the Donnager were actually made on Earth, United Nations Navy ships fire on MCRN ships in Mars' orbit, also destroying the Deimos deep radar station. The MCRN then ordered most of their fleets in the system to return to Mars and declared war on United Nations (UN).

After the Protomolecule was unleashed on Eros during the Eros incident, and its existence became known to the public, the Martian fleet nuked the Cronian moon of Phoebe into a thin gas that was sucked into Saturn’s gravity.

Ganymede Incident[]

In the eighteen months since the Eros incident, the Martian Congressional Republic (MCR) and UN have been in a bitter cold war.

The Ganymede incident was an event in which a human-protomolecule hybrid attacked Martian Marines and UN Marines on Ganymede, killing everyone except Martian Marine Gunnery Sergeant Bobbie Draper. The initial attack was misinterpreted by both the MCR and the UN as an attack from the other side, which led to a battle above and on Ganymede that claimed nearly three thousand military and civilian lives, as well as causing over five billion MCR dollars of infrastructural damage.

Slow Zone Incident[]

The MCRN sends a joint expedition fleet to the Ring with the UNN and OPA navy. Following the MRCN Hammurabi's pursuit of the Rocinante, The majority of the joint fleet enters the Sol Ring where the Slow Zone incident occurs.

Rebuilt fleet[]

By the time of the Conflict on Ilus IV, the MCRN had recovered significantly from its fighting with the UN in the war. The navy had sixteen battlecruisers and fifteen thousand nuclear warheads, alongside "high energy proton cannons".[15]

Defections and theft[]

Knowing that the MCR was facing an economic crisis due to mass emigration to new systems MCRN Admiral Winston Duarte organized to form a new government in the Laconia system using radical Belters as cover to escape the system with a third of the entire MCRN fleet. This was done by stealing officially decommissioned ships including many Corvette-class ships and giving them to the Free Navy to start a war.

Unknown to the Majority of the MCRN and the MCR government when the Free Navy conflict began Free Navy ships were able to approach the ship carrying the Prime Minister Nathan Smith posing as reinforcements. These ships then attacked the fleet at close range catching the MCRN off guard and forcing them to send the Prime Minister off on board the fastest ship available, the Razorback.

Confusion and war[]

With an entire third of the MCRN fleet gone rogue, and heading towards the Laconia system, with no known reason the MCR was in a crisis that caused the Prime Minister to be deposed. During this time the remaining MCRN fleet was largely kept back and was unable to pursue offensive operations until all personal loyalty could be confirmed.

Despite this, at least one MCRN ship carrying Martian Marines was able to join the Ceres Offensive led by the UNN and arrived as one of the first two ships (the other carrying UN Marines) to easily retake Ceres.

The remaining MCRN forces once reorganized and secured were able to join the Consolidated Fleet Offensive including most of the reserves protecting Mars.

Post War[]

After the Free Navy Conflict the MCRN joined the UNN as a part of the Earth-Mars Coalition Navy (EMC) operating more as a single entity.

Defence of Sol[]

In the Laconia-Sol Conflict, the MCRN was part of the Earth-Mars Navy with the Transport Union attempting to stop the Laconian Empire's venture to conquer the Sol system with its battlecruiser, the Heart of the Tempest. The EMC forces are eventually defeated at the Battle of Point Leuctra causing them to surrender.

Laconian Dominance[]

After the defeat to the Laconian Imperial Navy, the MCRN was integrated as part of the Laconian Empire. They were only allowed to operate individually while performing policing operations in the Sol system.

Discovery on Phoebe[]

The MCRN Donnager was sent to investigate the Cronian moon of Phoebe after contact was lost with a Martian station on the moon. Marines led by Lieutenant Lopez found the Martian scientists all dead.

Later after rescuing the surviving crew of the Canterbury, the Donnager was attacked by six Amun-Ra-class Stealth frigates. Lopez and his marines took the captain of the crew, James Holden and the rest of the crew to the MCRN Tachi in the hangar to escape the Donnager, although only Lopez of the entire Marines himself would make it onboard dying shortly after. The Donnager self-destructed to avoid capture.

After boarding an illegal mining Belter skiff the MCRN Scipio Africanus was attacked by the skiff. Surviving the attack the skiff was destroyed along with its pilot. The MCRN responded by increasing patrols and inspecting ships passing through its areas of control.

The MCRN Ambedkar was despatched from the MCRN Yangtse to board the Rocinante. However, shortly before boarding the Rocinante gave out an MCRN code identifying itself as an undercover MCRN vessel. The Ambedkar then withdrew and allowed them to proceed.

Eros Incident[]

The MCRN did not directly get involved in the Eros incident. Although a ship had been dispatched to Eros after the OPA traveled to the station to destroy it, the events of the Eros Incident prevented the ship from reaching before the station had moved.

Ganymede Incident[]

When an unknown foe attacked UN Marines and Martian Marines on the surface of Ganymede, ships of the MCRN Jupiter fleet became engaged with UNN Jupiter fleet ships in close range PDC [Point Defense Cannons) shootouts. The engagement was sudden and confused with each side believing the other had attacked them first. Ultimately the MCRN fleet proved victorious and UNN forces retreated.

A Corvette-class Frigate, the MCRN Karakum was dispatched to the surface of Ganymede to secretly take transport of a Hybrid, however, it was destroyed near the moon by United Nations Navy (UNN) missiles.

After the unsuccessful peace talks, UNN forces attacked the MCRN over Ganymede.

UN-MCR War[]

After discovering five MCRN Stealth C ballistic missile platforms the UN destroyed them all using Earth's railgun platforms, however, one missile platform was able to launch a single warhead, striking Goias Maior, in Amazonia, killing approximately 2 million.

The war enters a stalemate with the MCRN's more advanced ships and the UNN's vastly larger fleet causing them to be matched in battle.

Io Campign[]

The MCRN Hammurabi and its fleet divert their course away from Callisto to intercept the UNN Jupiter Fleet flagship, the Agatha King. When a Mutiny onboard the Agatha King occurs, Captain Sandrine Kirino of the MCRN Hammurabi enters a ceasefire with UNN forces that are firing on each other. Following the self-destruction of the Agatha king, the UN-MCR war effectively ends.

Slow Zone Incident[]

The MCRN sends a joint expedition fleet to the Ring with the UNN and OPA Navy. Following the MCRN Xuesen's pursuit of the Rocinante, the majority of the joint fleet enter the Sol Ring where the Slow zone incident occurs.

The blockade Run[]

The MCRN in the coalition with the UNN, Blockade the Sol Ring in preventing any civilian ship from entering the Ring space. Then serval Belter refugee ships run the blockade on the Ring causing the UNN and MCRN ships to fire upon these ships destroying most before entering the Ring Space.

Post War disarmament[]

Following the UN-MCR War and the end of their cold war with the UN, the MCRN reduces its military size, Causing an increase in ships being retired and veteran unemployment.

Seceded faction[]

Heading out on a supply run with two MCRN heavy frigates the MCRN Barkeith instead stopped at the Hungaria group meeting the Free Navy command fleet and transferred the heavy frigates to them. The Barkeith then traveled towards the outer planets.

A single MCRN heavy frigate alongside two UNN cruisers engaged five Golden Bough ships at the Engagement near Patroclus. The heavy frigate was reported destroyed, along with one UNN cruiser.

At the Battle for the Sol gate one Donnager-class Battleship, the MCRN Sagarmatha, alongside two UNN Truman-class Dreadnoughts was engaged by the Free Navy command fleet. Shortly before both sides engaged, a large stealth-coated micro-meteor cloud struck the three MCRN and UNN ships causing massive damage to all three ships. Despite this, the three enormous warships put up a stiff resistance destroying all incoming missiles with their functional PDCs. At this point, several torpedoes came out of the ring space and struck the already damaged Sagarmatha, causing a reactor detonation destroying the ship. Moments later an MCRN fleet appeared on the flank of the UNN battleships. This was, however, the Barkeith with a number of MCRN ships officially listed as lost in action (they were actually Admiral Sauveterre's rogue MCRN fleet). These ships fired upon the UNN battleships destroying both of them with their barrage of missiles.

This fleet had seceded from the MCRN and moved into the Laconia system. However, while entering the system, a Ring network anomaly occurred, disintegrating each ship.

Worn rank insignias[]

Insignia Rank Worn by
S02e09mcrnadmiralrankinsigia16m33s Admiral J. Peñano
S06E02Threestaradmiral Admiral (Three Star) Preston
S05E02mcrnpipsadmiral27m19s Admiral (Two Star) Sauveterre
S06E03onestaradmiral Admiral (One Star) Sandrine Kirino
S03E13captainrankinsignia04m05s Captain Sandrine Kirino, Chandra Lucas
S01e04captainrankinsignia06m34s Captain Theresa Yao
S05E02mcrnlieutenant27m52s Lieutenant Emily Babbage
S01e03lieutenantinsignia14m09s Lieutenant K. Lopez, Mazzuca
S03E13gunnerysargeantrankinsigia03m41s Gunnery Sergeant (MMC rank) Bobbie Draper
S03E13privaterankinsignia28m28s Private (MMC rank) Jed Trepp, Riko Oshi
  • Note that the insignias worn on-screen are inconsistent with different ranks appearing to wear the same insignia and several officers lacking insignias entirely.



  1. The Expanse Roleplaying Game, chapter 9 - Mars
  2. The Expanse Roleplaying Game, chapter 9 - Mars
  3. The Expanse TV Series - Season 3, Episode 5: "Triple Point"Referenced in dialogue.
  4. The Expanse TV Series - Season 2, Episode 12: "The Monster and the Rocket"
  5. Spacedock Donnager-class video
  6. The Expanse TV Series - Season 2, Episode 12: "The Monster and the Rocket"
  7. James S.A. Corey tweet
  15. The Expanse Novel Cibola Burn - Epilogue: Avasarala