Battle of Port Gallus

The Battle of Gallus was an engagement between the United Republics of Mars Home Fleet and the newly formed 3rd Battlefleet of the United Nations on an outer rim mining colony near Vesta (19900 kilometres) during July and August 2370. The battle began with the launch of the URMN offensive, Operation Ethos, on 28th of July, which had the objective of cutting off outer rim supplies to Earth. After the URMN offensive stalled on the solar-northern side of the operation field, on 29th of July, the UNEN commenced a counter attack with the launch of Operation Daimler against the rear of the URMN forces in the northern side. On the southern side, the UNEN also launched powerful counterattacks the same day, one of which led to a large clash. On 1st August, the UNEN began the second phase of Operation Daimler against remaining URMN ships.

The battle was the last major strategic offensive that the Martians were able to launch in the outer rim. Because the  invasion of Earth had begun, URM High Command was forced to have fleet reserves diverted to support the invasion of the Mediterranean, rather than use them as a strategic reserve for the outer rim. URMN's catastrophic losses of ships and the URMN flagship, URMNS Mikail ensured that the Earth could continue to be supplied with materials from the outer rim.

The Battle of Port Gallus was the first time that a URMN fleet had lost an engagment, though the course of the war would still remain firmly in the hands of URM as the majority of URMN was modernised, and the UNEN 3rd Battlefleet was one of three modernised fleets.

Planning
Martian intelligence agencies were able to locate the primary relay for shipments between the outer rim and Earth, and planned a major attack to destroy or capture Port Gallus. However, these plans were discovered by the UNE and facing losses on Luna and the loss of 20% of their fleet, quickly redeployed the modernised 3rd Battlefleet, preparing and ambush along the primary route through the port.

UNEN ships deployed were primarily equipped with spinal railguns, capable of hitting targets accurately up to 10,000km away. Fortifications were also prepared on Port Gallus, torpedos and heavy railguns were deployed on the port, with additional UNE Marines supporting the local garrison.

URMN planned for a simple attack, not anticipating any resistance. In the case of heavy resistance, the larger ships would advance first, as the older UNEN ships could not penetrate the hulls of any of the modern URMN vessels.

First Contact
Fighters and gunships made first contact at 23:04, 28th of July. The skirmish was indecisive, as losses were roughly equivalent and the defending UNEN was not dislodged. URMN would adapt their strategy, utilising fighter screens and cruisers to destroy what they were assuming were a small naval garrison.

In the early hours of the 29th of July, URMN forces entered the killzone of UNE railguns. Within 10 minutes, URMN had lost the cruisers Edge of Time and The Sorrows, with the Weibo's weapons disabled. UNE forces would reposition themselves, with most of the fleet scattering to minimise the risk of collateral damage from URMN antimatter torpedoes. URMN, now realising the presence of an entire fleet, proceeded to carry out their secondary plan, advancing the URMNS Mikail and URMNS Nhan Con Ngong to absorb fire.

Main Battle
The URMN fleet proceeded unhindered, with the URMNS Mikail undamaged. However, once the URMN Fleet came into range of the spinal mounted Large Mass Accelerators of the UNEN cruisers, all ships of the 3rd Battlefleet opened fire on the leading ship, the Flagship URMNS Mikail, crippling reactor 5,6 and 9, effectively disabling half of the Mikail's railguns.

URMN underestimated the UNEN fleet, the fleet commander present, Grand Admiral Schipper, took direct control of the entire Home Fleet, organising a defensive ring around the crippled URMNS, utilising as much of the flagship's heavy and super heavy weapons. The following manuever (known as the Schipper Drop), involved the URMN cruisers baiting the UNEN Baliff into the firing arc of the URMNS Mikail's super cannon, before rapidly descending beneath the flagship. The Baliff was hit with 3/5 of the super weapon's projectiles, instantly splitting the cruiser into 8 pieces, obliterating the cruiser and the shrapnel damaged the UNEN Alnahr Alkabir.

However, the UNEN was able to break through the north flank of the URMN formation, opening a direct line of sight to the command bridge of the URMNS Mikail. A short concentrated burst from the UNEN Washington's rapid railgun cannons destroyed the primary bridge, killing Grand Admiral Schipper.

Within 72 hours of arriving near Port Gallus, URMN had suffered the loss of five cruisers, a Grand Admiral and the disabling of the Martian flagship. While the UNEN had only lost two cruisers.

The collapse of the northern flank was quickly followed by a UNEN breakthrough from the front. The second in command, Admiral Mazur issued a retreat order, recalling the remaining seventeen cruisers to the nearest allied base. A rearguard action would be fought by the crippled URMNS Mikail, delaying any UNEN advance for six hours, before all personnel were evacuated and the ship scuttled. The resulting blast destroyed the still nearby UNEN Alnahr Alkabir.