UNSC Southern Cross

"Magnitudo animi constantiam spirat."

- Ship motto

The UNSC Endeavour (hull code: DD-347) is a venerable Beagle-class assault destroyer, and one of two ships to have participated in the Harvest Campaign and the Siege of Sol. The latest in a lineage that hailed back to the seventeenth century, the Endeavour is one of thirty-five destroyers built to trial the installation of state-of-the-art hangar facilities on light-tonnage warships. While still possessing two full-sized fusion reactors, a relatively-high acceleration and as thick a hull as the baseline class, its armaments were lacking thanks to the removal of several Archer missile pods and the downscaling of its Magnetic Accelerator Cannons. Despite these significant drawbacks, it remained a solid vessel which outlived the sisters it was built alongside.

Design and construction
During the Insurrection, the wildfire of conflicts arising in the Outer Colonies meant that troop transports of all sizes were in high demand. To meet this need, the CMA initially purchased older civilian ships to act as such, arming them and providing them with an escort to ensure this protection. While this was adequate for larger assault ships, they could not always spare the resources to protect a convoy of refitted freighters, thanks to both the escalating crisis and increasing pressure from the rival UNSC Navy. Because they were too slow to flee, and too poorly-armed to protect themselves, and they were frequently attacked and pilfered by rebel boarders. In response, the CMA issued a contract for a light-tonnage warship that could double as a transport and act as a fleet ship armed with a MAC. SinoViet Heavy Machinery submitted two designs to the committee; an updated version of the Charon-class light frigate, and the Beagle-class assault destroyer. While the former would win the contract, the latter intrigued the CMA enough for a preliminary flight to be constructed for testing purposes. A block of 13 destroyers were constructed by the subcontracted Diadel Systems, which included the Endeavour. A further 23 ships would succeed them, although only the Endeavour would survive to 2552.

Like all Beagle-class destroyers, the UNSC Endeavour shares most of its hull and superstructure design with the Halberd-class destroyer. At 480 metres in length, it was only five metres shorter than the design it was based on. Past its arrowhead bow, the differences are minimal. This mainly involved replacing certain areas of the hull with 0.4 metres of durasteel armour, which sacrificed protection for speed, as well as a number of keel-mounted thrusters to hold it up while operating in a planet's atmosphere. The bow is slightly different, with a larger hangar bay that is half-again as large as on its more common counterparts, and a smaller upper hull. The hangar is divided into two sections; a long flight deck that is located on the upper floor, and a general-purpose bay that accommodated both dropships and ground vehicles on the lower one. Both decks use different airlocks, so they can launch and receive different squadrons at the same time. However, only aircraft entering the front hangar door can benefit from the advanced gravitic breaking system. The upper plate on the bow that ran between the raised plates of titanium-A battleplate is unusual in that had a series of automated elevators and armatures that could rearm and refuel up to three space fighters in the middle of battle. Intended as a forward-thinking feature, it was hoped that the UNSC would introduce a smaller interceptor model to take advantage of it. No such aircraft would ever reach the light of day, so the system lies unused. In homage to its maritime namesakes, the Endeavour is often seen sporting red-or-blue war paint resembling waves on its bow and wings.

In terms of armament, the UNSC Endeavour 's original ship-to-ship armament consisted of two Series-2, light coil MACs. The Series-2 MACs were intended for use on corvettes, and fired far smaller slugs in exchange for higher speed and quicker recharge times. Backing this up were 18 M58 Archer missile pods, each with five silos. These were general-purpose missile pods that are effective against other ships, but could also be used against larger gunships and space fighters if necessary. They could also carry a vast assortment of warheads, with armour-piercing and counter-shielding being the most popular. It lacks the M870 Rampart emplacements, and in their place are eight M37 Suppressor turrets, each with twin-linked 279mm naval autocannons. They could be used for defeating missiles, but they were more intended for use against other ships and space fighters. Instead, 19 M710 20mm turrets were installed for this purpose. For use against far slower and heavier opponents, two M81273 fusion rockets were embarked, each with a variable payload. Like on regular Halberd-class destroyers, a Mark 45 fire director was used to vastly increase its accuracy at extended ranges of 50 kilometres or more.

Over the course of the war, the Endeavour would be refitted to carry a total of 26 Archer missile pods, and its Suppressors were replaced with more powerful M40 turrets. In addition, it would often replace its fusion missiles with Shiva-class nuclear missiles armed with a 50-megaton Californium warhead, optimised for a vacuum.

The Endeavour was laid down above Chi Rho on August 22, 2518, as the third ship of its flight. With the kinks worked out in its predecessors, it would enjoy few complications during its construction. It was launched from its drydock on January 27, 2519, and underwent a series of rigorous space trials while it was being fitted-out. These would discover that it was substantially more durable than what was considered normal for its class. It was formally commissioned as the CMA Endeavour on March 19, 2519.