The Martian Congressional Republic Navy (MCRN) is the millitary navy of the Martian Congressional Republic. MCRN is under the command of the Martian Cabinet. And the minister in charge is the Minister of Defence. But the fleet ,usually, takes its orders from the Military High Command.
The MCRN was formed shortly after the creation of the Republic and Martian independence. He was confronted several times with his Earth counterpart, the UNN. Among the notable events was the Vesta blockade.
After a while, the MCRN eventually joined forces with UNN to form a coalition. This is to ensure security and stability in the solar system. The alliance is going through a major crisis during the Eros incident. Or both sides were ready to shoot each other. But the situation was quickly under control and a desatre avoided. A disaster avoided by avoiding another disaster.
When the Earth decided to evacuate Ceres, the MCRN deployed military forces in the area. A military force that eventually served, as Earth and Mars landed troops to take Ceres back into the hands of OPA terrorists.
But tensions are not decreasing, and both Earth and Mars are deploying more and more forces and concentrating them in strategic locations. Such as Ganymede.
And what must happen, happens. Both sides start a violent battle for control of Ganymede. The battle is long and bloody, the victims are numerous. And the rest of what were once glorious ships, scatters the orbit of the Jovian moon.
A ceasefire was concluded and a part of the moon fell under a military jurisdiction.
The MCRN divides its operations and commands into several fleets. Each of them under the command of an Admiral. But some fleets, smaller than actual fleets, may be under the command of an officer other than an Admiral. Like a Vice-Admiral, for example.