UNSC Southern Cross

 "If there's one thing I know, it is that the Cross is a survivor. She has endured the worst the Covenant can throw at her, and while it may have taken some time, she eventually came back asking for more. And now that she has been rebuilt from bow to stern, I expect that spirit to live on for decades more; and when she finally meets the end, she, nor her crew, will not go quietly."

- Commander Tom Žagar, at the Southern Cross ' recommissioning ceremony.

The UNSC Southern Cross, formerly christened the CMA Endeavour, was a venerable and one of two ships to have participated in the Harvest Campaign and the Siege of Sol. After leaving service, she was preserved as a museum ship by the Victory Museum of Tribute.

Specifications
Part of the last continuous class of cruisers ordered by the CMA Navy, the dimuitive Southern Cross and her sister-ships were the smallest practical vessels capable of carrying out the cruiser mission for their time. This demanded enough fighting power and operational endurance to carry out missions single-handedly under all conditions, while also able to take on flagship duties for small squadrons in a pinch. Complicating this was the CMA's desperate need for a large warship capable of not only defeating groups of new MAC-armed frigates and destroyers, but also running them down should they attempt to flee.

As-built, the Southern Cross was one of the lightest and most compact more compact than other ships of her class, measuring 747 metres in length and massing in at 5.23 million metric tons. Although she was powered by a Solar Dynamics SP860 fusion reactor, by the time she was laid down the CMA had experienced problems with its integrated propulsion kit and so completed the cruiser with ReGen Inc's KPS-39 fusion drives instead. While not quite as fast nor as agile as a destroyer at full thrust, the Southern Cross 's more expansive radiator coverage allowed her to sustain this velocity for longer. Main protection was provided by 1.5 metres of titanium-A1 battleplate and, uniquely, a consumable electromagnetic reactive armor scheme that activated only when the main hull was breached. Active defence systems consisted of the basic for CMA vessels. A VEIL jammer array was provided for throwing off target locks, while multiple AN/SLQ-371 Bastille countermeasure launchers were there to deploy chaff and dumbfired decoys to draw away missiles.

Part of the reason for the Southern Cross 's smaller overall size was due to a series of modifications that improved her planetary support capabilities, which ate up most of the generous space allowances normally granted to Achernar-class ships. As well as an integrated command center allocated for use to Marine personnel, the Southern Cross was built to allow for limited atmospheric operations. This was the most challenging part of her construction, as zenostium antigravity plates were unable to provide sufficient lift. This was why she had keel-mounted thrusters, a feature that fit in more with First Wave starships than anything from the 26th century.

Refits
"What you are looking at is the last original part of the ship. Every other wall, beam, and electronic has been replaced or rebuilt three-times over."

- Petty Officer, 3rd class Michael 'Stuck' Bennet

Prior to 2528, the Southern Cross had received a small suite of improvements, as five years of constant action caused severe wear on its systems. Most of its systems replacements were minor and hardly affected its performance, although its powerplant, electronics, and even its superstructure were all modified to some capacity. However, two significant changes were made. The first was the installation of a TN-91sy/n Triad targeting suite and its associated targeting RADAR. "Donated" from the, this bulky computer system greatly improved the cruiser's accuracy, making even specific targeting of enemy components viable at long-range. The second was a controversial array of radiators at exposed parts of the hull. While it enabled the Southern Cross to overclock its reactor and engines well above their designed limits and still remain cool, it left holes in its armor that were never fully addressed over its lifespan. The only other noteworthy change was the increased complement of point defense guns, in a desperate attempt to better protect it from plasma torpedoes and resilient Covenant strikecraft. Because the shipwrights had to rely on whatever weapons were available, it was not composed of one homogeneous type of turret, instead being made up of everything from the M810 Helix to various models of Rampart guns. A number of other weapon systems were temporarily fitted - the Southern Cross at one point boasted seven silos for M280 Ares missiles sloppily fitted onto its keel, which were so rarely rearmed that these were removed during the 2528 refit.

In 2528, after suffering extensive damage following the Battle of New Tharsis, the Southern Cross limped back to the regional shipyards of Charybdis IX, where it underwent its first major refit. This was an expansive affair, involving the modification of vital internal equipment, the movement or mutation of its armor and hull to maximize protection, and the removal of dozens of patchwork repairs. Most prominently, its forward bow was angled downwards and expanded in size, originally to allow for the installation of a third MAC. However, high demand for such weapons saw the space being given over to supercapacitors, munition storage, and more accommodations for Marines and pilots. Personnel assigned here were nicknamed the 'poundees,' as the firing of the MACs would rock or pound the entire deck when they fired. The last change was the installation of 8 quad M112 Viper 375mm/26 cal naval coilguns beneath the MAC, offering a substantial increase in firepower.

No new major refits occurred between 2528 and 2552, as older material from the CMA was being quickly expended during the remaining battles in the Outer Colonies, while new material was diverted to the construction of new starships. Once again, any changes were made during repairs. An additional six M58 Archer missiles were added, along with 48 M340A4 Streak missile silos that provided enhanced counter-fighter defense. Various improvements over time strengthened the hull, and the obsolete VEIL jamming suite was finally removed and replaced with a Mark XII GREY MIST wide-spectrum jamming computer. The engines had been exchanged on no less than four occasions. The newest ones, four ILT-DTF-9 fusion drives, were secondary units that were taken from a scuttled heavy cruiser, and resulted in a thrust increase of 45% over the original models fitted to the Southern Cross.

After the Human-Covenant War, the UNSC Navy authorized a series of enhancements to first fulfill its need as a test vessel for Project SPHINX, and later expanded into a full-blown rebuild in 2554. Almost every single component of the cruiser was gutted and replaced, which drastically increased its performance in all areas and made it competitive with far more modern warships. While too expansive to list each change individually, there were some highlights. Under SPHINX, the Southern Cross received a Kaalt Nu-pattern borer, a small Covenant-built faster-than-light engine. This changed the cruiser's role into a rapid response and messenger ship, as it could effortlessly outpace ships that boasted the newest CODEN drives that were just entering service. It was also under the program that a Rutherford DIS-3081b compound fusion reactor was installed, a completely-new powerplant that was a scaled-down version of the model fitted onto the UNSC Pillar of Autumn. This allowed the Southern Cross to overclock its reactor by over 300% for short periods, as it did not have the advanced cooling system to nullify overheating.

The rebuild of 2554 also made significant changes to its armament. The twin MACs were exchanged with the Mark IX, light coil MACs, which were a complete upgrade over the old Series-2. Most significantly, they recycled about 35% of the energy used in the firing process back into the capacitors, enough to fire an extra shot per charge. The venerable M66 Sentries were finally removed and replaced with triple-turrets equipped with the new M74 Sentry autocannons. M58 Archer missile pods were still present, but their numbers had been increased to 24 pods. The refitted Southern Cross was bristling with dedicated anti-fighter weaponry: 48 cells of M340A4 Streak missiles, 8 quad M910 Rampart 105mm guns, and no less than 120 M710 Bulwark 25mm guns were present to break up any space fighter attack. Two silos for the Ragnarok-class nuclear missiles, each with a 40-megaton nuclear fusion warhead, replaced the fusion missile turrets that were fitted. These were considered weapons of last resort against opponents that significantly outclassed the cruiser, and their EMP qualities made them much more viable against Covenant warships. All these changes leaned the cruiser much closer to the air defense role than it ever been before.

Construction and commissioning
The cruiser that would be christened under its first name Endeavour first began construction in orbit of Chi Rho by Eptá Potámia Dockyards, who were subcontractors of Great White Spaceworks. It was first laid down on August 22, 2516 as the third of the five cruisers built of its batch, which ended with the completion of the CMA Sirius in late-2522. As its previous two sisters allowed Diadel to identify and fix many issues with manufacturing and shipping of parts, the cruiser suffered no construction delays and even finished fabrication two months ahead of schedule. It was launched on November 27, 2518 to complete the fitting-out process.

As construction came to a close, the cruiser was subjected to a rigorous set of space trials, intended to test the operation of its systems and general integrity. This consisted of a series of hard burn accelerations, sensory tests, and low orbital passes. Although these were generally quiet affairs, the third of these trials was noteworthy. The ship was caught in an intense comet bombardment that saw shards of rock impact the cruiser's hull, which forced it to conduct extreme evasive maneuvers to escape damage. One of these turns saw it unintentionally collide with the MSV Ivory Tower, a large maintenance tug that was sent to rescue it. The ordeal would delay its commissioning, but the minimal, almost superficial extent of the damage showed that the cruiser was much more ruggedly built than was first believed by its builders. It was commissioned as the CMA Endeavour on March 19, 2519, and was delivered to the CMA a mere three days later. It then departed the Ectanus 45 system, manned by a rookie crew under the command of Lieutenant Commander Asia Vespa.

Insurrection
"Kids on Fjord fight better than you."

- Chief Warrant Officer 4 Kores Van Schalkwyk, to the Endeavour 's insurgent crew.

The CMA Endeavour first served in the 173rd squadron, a light naval unit that operated in the Lurone, Rawadi, and Rowena Sectors of the Vela-Scorpius Quadrant. In this guise, it was primarily used to conduct light troop movement through the region, where it ferried elements of the 276th Colonial Army Battalion towards unrest hotspots on Pumice and Cadence. It lent naval support where possible, but thanks to the small-scale of the fighting, its support was generally limited to logistics and coordination. Other tasks included convoy protection duties to the habitats of Campbell's Landing, in an effort to deter losses to piracy in a navigational hazard zone around it. Most of these tasks were quiet affairs, as nobody realistically wanted to pit themselves against a Colonial Navy pocket cruiser. Instead, it generally acted as a glorified rescue ship, rescuing numerous civilians and businessmen whose ships were stranded or forced to be abandoned.

In October 2521, the Endeavour was reassigned into the 114th Rapid Strike Squadron, the largest and most active CMA naval unit in the Asgard Stratum, as a replacement for the destroyer. This reassignment was also to partially cover the refit of the carrier, with the Endeavour taking over some of its servicing duties for the four months it was in dock. Within the 114th, the cruiser was supposed to assist any starships in distress, where it would quickly move to dock and embark any crew and cargo that can be saved from disabled craft and fight off any attackers. The agricultural content of these freighters meant that it was vital that shipping losses were kept to a minimum, and the Endeavour was involved with the rescue of 19 civilian freighters and four warships during 2522 alone. However, the 114th's power meant that its escorts were responsible for tracking and hunting down any significant insurgent elements in the region, as well as reinforce any CMA garrisons that were struggling to put down unrest. For this need, the cruiser participated in putting down the insurrections of Madrigal, Green Hills, and especially Redstow VI, where it supported ground incursions with orbital strikes at the cost of escalating civilian casualties. However, the sudden increase in readiness and activity, as well as the now-notoriously low standard of training given to CMA recruits, meant that the Endeavour 's largely-inexperienced crew were seen as both incompetent and lazy. This was almost dangerously so, as it almost fired upon allied vessels on several occasions; this reputation would only be erased following the start of the Human-Covenant War.

In February 2523, Vespa stepped down as the Endeavour 's commanding officer, and was replaced by Lieutenant Commander Chi Kariuki. An ambitious officer, it was under her leadership that the cruiser became host to sympathizers of the Biko Independence Army (BIA). At first, the only assistance the crew offered were leaked communiques sent through the squadron, and Kariuki's desire to impress saw these quickly shut down. It was only through negotiations and bribery of her communications officer, Lieutenant Patryk Adamczyk, that operations escalated. Throughout the rest of the year, the Endeavour actively assisted the BIA's efforts by providing dead drops of infantry equipment and firearms, starship munitions such as Archer missiles, and even entire vehicles and dropships when possible, all of which was smuggled back to Biko. This assistance was also afforded to other Insurrectionist groups, where it misdirected CMA and UNSC forces by providing false sensor reports. It even faked the deaths of Godfrey's Commandos, one of the Secessionist Union's most elite forces, during Operation: THUNDERBIRD by quietly folding them into the crew as their own department.

All of this eventually culminated in a scandal. In early 2524, the BIA used many of the weapons they received from the Endeavour in their fifth uprising, which was swiftly put down by UNSC forces. Analysts from ONI Section One were brought in to scour through the wreckage, as well as interrogate one of the captured insurrectionists for information. While they were able to determine that the equipment was stolen from the CMA, the exact origin was ultimately unknown as their prisoner did not survive. As a result, ONI covertly seeded teams of investigators among CMA garrisons to hunt it down. One of these teams, composed of Chief Warrant Officer 4 Kores Van Schalkwyk and his Navy handler Lieutenant Theodora Papadopoulos, were officially serving as trainers for the Endeavour 's. Their attempts to uncover traces of duplicitous activities ultimately saw them eventually captured by the rogue crew. It was only through a combination of uncertainty on how to quietly kill the ONI agents and shoddy security that allowed Schalkwyk and Papadopoulos to escape, who took with them evidence that connected the cruiser to not only the BIA, but also exposed the rampant insurgent activities in the region.

The Endeavour was immediately suspended from operations, and its entire crew were detained and interrogated by Section 1 officials. Many were pressured to resign, with LCDR Kariuki and several of the senior officers being court-martialed for treason and negligence. The few that were released were reassigned. The ship itself was thoroughly swept of any listening devices, and its databanks were recovered for further analysis. When it finally returned to service in January 2525, it would be under an entirely-new crew.

Covenant discovery
The CMA Endeavour 's first actions in what would become known as the Human-Covenant War occurred in May 2525, when it was sent to investigate the loss of the CMA cruiser Urban Encroachment in the Upada Sector. A four-week search was extended into six when a second starship, the CMA Empyrean Jewel, disappeared in the same region. No traces of either starship were discovered, something which led to the regional command theorizing that they had been hijacked. As a result, it was ordered to rendezvous with the frigate CMA Raltstown to escort merchants through the Asgard Stratum in hopes of deterring raids.

However, when the civilian craft of the CAA Astrography Charting Mission deployed to the Aruna Sector failed to check in, the entirety of the 114th Rapid Strike Squadron was sent in to locate them on July 13. After 16 days of searching, the Endeavour recovered Item-291X - an alien fragment that appeared to be have once been part of a ship's hull. Two days later, the cruiser met up with another CMA corvette to verify the discovery of the wreckage belonging to one of the Mission's command ships, the CAA Babyloniaca. Preliminary analysis of the damage was undertaken, where it was discovered that it had been subject to an intense bombardment of high-temperature plasma, which breached all decks and fused the propulsion systems. More importantly, the Endeavour 's weapon officers and chief engineer both noted that the damage could not have been caused by any known weapons they were aware of. The wreckage was taken back to their home base at Biko so it could be analyzed further. Both Item-291X and the Babyloniaca convinced the regional CMA command to keep the 114th Squadron in the area, as well as reassign the smaller 38th Scout Flotilla to assist them.

On October 26, the Endeavour participated in the Skirmish of CRT-99-LP. It arrived into the system to exchange supplies with the corvette CMA Johnston, only to find itself suddenly attacked by a Covenant attack ship. In an action lasting a minute and a half, the cruiser took several blows from the much smaller alien ship, breaching D-deck on the bow and killing four people. Meanwhile, the only hits from the human side were from a salvo of one of the Endeavour 's naval autocannons, with its missiles rendered completely by its jammers. While it did force the raider to flee, no damage was registered on the enemy ship. The cruiser immediately began a rescue of the Johnston 's 13-strong crew, although only a single comatose survivor was recovered.

The Endeavour towed the Johnston back to the nearest CMA outpost at Green Hills, where they filed an urgent report to CMA Command concerning the engagement with an unidentified alien vessel. They were instead surprised to find that they received orders by the UNSC High Command, signed by the UEG Minister of Defense, to head with best possible speed to the nearest UNSC naval base at Falaknuma in the 18 Scorpii system. Upon arrival, the two ships, along with the recently-arrived CMA Hercules, were temporarily grounded as ONI Section One teams combed over them for any intelligence on their potential adversary. These included thorough interrogations of the crews, reviewing computer readings taken during the battle, and inspecting the damage incurred to discover new insights. Repairs were halted while this process was ongoing.

In light of ONI's conclusions and the discovery of what happened to Harvest, the UNSC declared a state of emergency on November 1, forcibly placing all CMA personnel and property under its direct jurisdiction. With the UNSC already maintaining a ship with the same name, the cruiser was rechristened the UNSC Southern Cross, and major software upgrades were implement to allow it to interface with the UNSC battlenet and communications systems.

Cole Campaigns
The UNSC Southern Cross, along with the other few warships that had already fought against the Covenant, were reassigned into the massing Battle Group X-Ray. The newly-returned Vice Admiral Preston Cole specifically requested these ships in hopes that their crews could better inform his upcoming strategies. In any case, the cruiser participated in the Second Battle of Harvest, where Cole's fleet attempted to destroy the single that orbited the planet. It was first tasked with screening the larger cruisers from incoming plasma fire, but then moved forward when it became clear that the fleet's countermeasures were unless against the Covenant warship. Considered too light to operate with the other cruisers, it joined the destroyers in swarming it, but the near-misses and glancing hits kept the Southern Cross away while their foe's shields easily withstood their fire. The entire fleet was almost about to retreat when Cole ordered the entire fleet to target a specific part of their opponent's bow, and coordinated their salvoes so they would hit at roughly the same time. This overwhelmed its shields and quickly led to its destruction, giving the UNSC its first major victory in the Human-Covenant War.

The UNSC Southern Cross participated in the Battles of Green Hills and Alpha Auriga with Battle Group X-Ray, but the small size of its MACs eventually saw it transferred into a support role. Instead, between October 2526 and February 2527, it served in a wolfpack with two other Halberd-class destroyers, where they departed from Harvest to raid Covenant logistics lines. They claimed to destroy thirteen ships over that four-month period, but further success was halted when the flotilla was lured into a trap. The Southern Cross was the only survivor of the bloodbath, as it was holding back from the main force when the attack occurred.

The Harvest Campaign
Once it finished repairs in June 2527, the cruiser was assigned to Battle Group D, who were charged supporting the invasion of Harvest. Although the system was not hotly contested by the Covenant, there were still a few holdouts that were stubbornly entrenched on its surface. Before it even arrived, the UNSC Southern Cross had already saw action when it intercepted a small, lightly escorted supply ship, though after an extended chase the vessel ultimately escaped.

Once it established orbit, the cruiser supported ground offensives in the Western Edda region by providing a mixture of fire support, imaging for reconnaissance and navigation, and acting as a forward operating base away from the theatre's assault ship, the. It directly participated in Operation: RIVER DANCE, where it deployed teams of ODSTs to find and destroy known Covenant communications and sensor stations, allowing the troops below to make a surprise march on the city of Thrudheim. It directly attacked a number of smaller regions, particularly those that were protected with anti-air defenses that could keep away other frigates. The few Covenant excavations sites that were captured intact were carefully examined by ONI officers on the cruiser, although they were unable to find out what they were looking for.

In November 2527, a massive Covenant counter-attack of Harvest changed the campaign for the worst. The Covenant's Fleet of Valorous Consecration appeared in force and clashed with the UNSC's fleet for control of the system. Battle Group D began to offload as much personnel and supplies as they could before withdrawing, and the Southern Cross worked with the other frigates to destroy as many of transports and fighters as they could. The Covenant retaliated in kind; a wing of 213 strikecraft attacked the cruiser and inflicted damage, but support arrived quickly enough for the Southern Cross to remain operational. Large sections of Western Edda had to be abandoned as it could no longer be maintained without orbital support. Finally, on December 3, Battle Group D was forced to withdraw as three arrived to decisively remove any UNSC presence in orbit. As one of the last vessels to leave, the Southern Cross was pursued by one of these destroyers, although late support from the cruiser saved it from destruction. It was towed back to New Tharsis for repairs, unknowingly being tracked by the Covenant.

Battle of New Tharsis
The Southern Cross was reunited with the 114th Rapid Strike Squadron for the first time in three years, when the sole surviving vessel, the, limped to New Tharsis for emergency repairs and reinforcements. While the 114th was awaiting for replacement ships, New Tharsis came under siege by the survivors of the Fleet of Valorous Consecration, which were now tasked with causing as much damage in the immediate region as possible. The shipyards of New Tharsis, and the factories below, were the beating heart of the UNSC's war effort in the Asgard Stratum, making it a prime target for the Covenant armada.

The Southern Cross participated in the first battle between the UNSC defense fleet, divided between Commodore Admiral Ashok Raymond's 114th Squadron and Rear Admiral India Martel's Battle Group Roma, and the Fleet of Valorous Consecration. This costly engagement managed to beat back the Covenant, but was unsuccessful in stopping one of their from reaching the ground. In the aftermath of the battle, Ashok transferred to the Southern Cross to conduct a search-and-rescue operation, one that was cut short when the Covenant attempted a second attack. Holding back to coordinate the fleet, this left it in the prime position to pursue when another enemy corvette made a break for the surface. It and the UNSC frigate Winter's End both followed the Covenant vessel through New Tharsis' atmosphere, fighting in a running gunfight. Though the Winter's End had to disengage due to damage, the Southern Cross maintained pursuit, and they eventually reached the Covenant's primary base of operations on the surface. Under simultaneous fire from anti-aircraft guns and the two Covenant corvettes that bypassed the UNSC fleet, the cruiser was forced to withdraw, though it deployed a nuclear warhead that annihilated the base and damaged the two enemy ships.

With their primary base destroyed, and the UNSC fleet in orbit crippled from the last engagement, the Covenant invaded with the rest of their ships to reinforce their holdings. With the orbiting capital ships unable to assist, Raymond transferred his flag to the Southern Cross permanently, and used it to coordinate naval and air support. Although it fought in a number of minor battles, such as when it held off Covenant fighters to allow the Drawn maritime fleet to escape, the rapid Covenant advance meant that it was held back until the Battle of Obsidian, the planet's capital city. Supported by the remaining fighters, heavy frigates, the Southern Cross clashed for superiority with the Covenant's three remaining escort ships for air superiority. The superiority of the alien warships forced the Southern Cross and its flotilla to fall back closer to the city limits, under rapid pursuit. This was, however, a feint: Raymond wanted the Covenant ships to be drawn deep into range of the well-camouflaged planetary defense guns, which suddenly opened fire. Under fire from all directions, and the fleet rallying under a new attack plan, two of the Covenant ships were quickly destroyed while the third escaped. Their lent fire support quickly routed the Covenant ground troops from the city.

The destruction of the three enemy ships had profound implications for the rest of the campaign; whenever because of damage or being destroyed, the Covenant's only intact ships were all heavier units. Without the speed needed to catch the UNSC ships, the Southern Cross and the other frigates were ordered to support ground operations and raids, usually to draw the Covenant ships and fighters away for various ground operations. It participated in the Battle of the Emerald Sea, where it and maritime ships succeeded in bringing down the Covenant's sole CCS-class battlecruiser.

The Years of Hell
"These are hard years. We've lost so many good people, many of them close friends, and it is taking their toll on me and the crew. Everyone knows that they will probably die in the next few weeks, and I cannot feel anything when I add an acquaintance's name to the casualty lists. I wish I could say that their deaths meant something, but I know that's a lie. I don't know how to maintain morale in these kinds of conditions."

- Excerpt from the personal log of CDR Aditya Misra, describing her brief captaincy on the Southern Cross.

Following its major refit, the Southern Cross and the rest of its squadron were briefly deployed in convoy search and escort duties. They were only able to search a handful of freighters before a new front had opened up in the Armstrong Expanse, requiring all available ships to be consolidated into a new fleet unit - the 16th Defense Fleet - to counter the Covenant advance. This period was one of intensive combat as the UNSC struggled to hold onto their territory. In the rest of 2528 alone, the Southern Cross participated in over three dozen engagements, with most of these being aborted attempts to board enemy warships in hopes of collecting intelligence. However, it did assist in evacuating over 370,000 people from Campbell's Landing, where it directly protected the civilian convoy while three capital ships held off six CPV-class destroyers.

The Southern Cross was part of the squadron that escorted the remnants of Battle Group Tsushima back to Nuevo Cuzco, who had been swiftly beaten at Midvale. This led to widespread food shortages throughout the sector that greatly impacted the morale of its crew. It later participated in the battles of Hat Yai, Cadence, and the Indra Asteroid Belt, where although it was supposed to be part of the transport groups, the UNSC's inability to maintain orbital superiority brought it directly into combat time and again. The 16th Fleet became so desperate for ships that the Southern Cross never stayed in dock for any longer than a month, with most of the repair work rushed to return it to the frontlines. This was so poor that the hull would crack when entering a planet's atmosphere. So much work had to be done that its damage-controls team were nicknamed the 'sleepless ones' by the rest of the crew.

Things only intensified from 2532-onwards. During Operation: MOONLIGHT, the Southern Cross supported the 16th Fleet's efforts in reclaiming Hat Yai by providing troops and fuel for prowlers. It later fought in the Second Battle over the colony, where it escorted the assault ships through the hole in the Covenant's defenses. Although some initial success was achieved, with ODSTs sabotaging most of the war industry present, the operation was quickly shut down as losses reached unacceptable levels. This led to a ban on offensive missions, with only prowlers granted an exception. As a result, all naval ships in the Armstrong Expanse were ordered to Kingston.

The subsequent Battle of Kingston was a massive campaign that attempted to hold back the Covenant's expansion. As most of the prowlers were deployed to raid enemy logistics, minelaying was instead transferred to the frigates and destroyers of the 114th Squadron. The Southern Cross seeded minefields around identified jump points and travel zones using 500-kiloton non-nuclear explosives, and while a number of kills were scored, the cruiser endured heavy resistance that sometimes forced it to abort the operations. As the battle progressed, it shifted to escort missions to deter attack ships, taking heavy damage in the process. It was during the latter that it suffered a near-catastrophic hit from a plasma beam that crippled its MAC and gutted its keel, requiring it to pull out of the battle to receive repairs at Hollow Point.

SPHINX involvement and recommissioning
In the aftermath of the Battle of Earth, UNSC engineers were sent to the Southern Cross 's crash site to evaluate what components could be salvaged for new construction programs. Their analysis discovered that, aside from the keel, the overall structure of the cruiser was in surprisingly good condition, and they recommended that it be raised and brought back into service. After nearly a month of repairs, the Southern Cross 's engines were fired once more and, with assistance from nearby tugs, it was led into an orbital drydock. However, work paused once it was discovered just how old many of its components were. While a pocket cruiser was considered useful, the cost of its repairs and upgrades made it unattractive to the UNSC Navy's budgetary officers, who debated about whenever to retain it or sell it off for scrapping.

The fate of the old warship was put to rest when Project SPHINX acquired the hull. After being moved to a backup facility at Titan, the Southern Cross was given patchwork repairs and converted into a technology test ship, which it would serve as for the next two years. It received Covenant antigravity plating and a small borer taken from a captured, and put through rigorous experiments that tested the borer's capabilities and reception to UNSC control systems. This included several dangerous atmosphere-to-atmosphere transitions that almost tore it apart, although improvements from SPHINX's engineers would make later trips much more comfortable and safer. It also experimented with a number of other components such as plasma torpedo silos, where it was found that the cruiser's reactor did not have the output to allow it to function. This led to them replacing it altogether with an upgraded model. The torpedo tests were a failure, as on two occasions, they failed to respond to the Southern Cross 's guidance signals, while on the third the munition overcorrected and almost hit it.

With their desired experiments completed, SPHINX formally returned the Southern Cross back to the Navy on September 4, 2554. Although they removed much of the equipment they installed on it, the borer was left intact in order to allow it to act as a keystone ship in UNSC fleets. The Reyes-McLees Corporation were contracted to fully modernize it at their Martian shipyards. The Southern Cross was formally recommissioned and handed back to the UNSC Navy on November 18, and left the shipyard under the command of Commander Tom Žagar.

Crew
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Captains

 * CPTN Taylor Gai (January 2519 - March 2519): Commanded her during her space trials.
 * CPTN Asia Vespa (March 2519 - February 2523): Transferred to command the frigate CMA Swipe Left.
 * CDR Chi Kariuki (February 2523 - October 2524): Court-martialed and dishonorably discharged by ONI.
 * CPTN Costică Ionescu (January 2525 - January 2526): Killed during the Second Battle of Harvest.
 * CDR Wieland Hauer (March 2526 - February 2527): Killed during the Skirmish of CP-99 system.
 * CDR Anargul Eldar (May 2527 - 2531): Field-promoted to the rank of Captain and transferred to Naval Command of New Tharsis.
 * CDR Aditya Misra (September 2533 - July 2535): Killed during the Battle of Hollow Point.
 * LT Govind Chaudhary (July 2535 - August 2535): Acting Captain, imprisoned after his crew mutinied against him.
 * LT Lochana Rao (August 2535 - November 2535): Acting Captain, relieved after returning the Southern Cross to port.
 * CPTN Róża Stawski (January 2535 - April 2537): Killed in action.
 * CDR Shannon Hambleton (2541 - 2545): Promoted to the rank of Captain and transferred to the.
 * CDR Tom Žagar (2553 - present): Current serving CO.

Bridge officers

 * LT Patryk Adamczyk (September 2522 - October 2524): Communications officer, discharged by ONI.
 * LCDR Harry Hamilton (August 2523 - November 2529): Weapons officer, killed in action.

Miscellaneous
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 * CWO4 Kores Van Schalkwyk (March 2524 - October 2524): UNSC technical liaison and trainer, transferred following the completion of his mission.
 * LT Theodora Papadopoulos (March 2524 - October 2524): UNSC naval liason, transferred following the completion of her mission.

Mascots
The Southern Cross ' first mascot was a female diamond python named Scarf. Confiscated after a civilian freighter was searched in 2528, her discovery was never reported and she was swiftly adopted by the engine crew. Known for her placid behavior, she was remarkably easy to handle and liked to intertwine herself in the staircase railings. Her complete lack of any threatening behavior was why her handlers occasionally slipped her into the quarters of various crewmembers for a joke. In her later years, it became a tradition for her to be slipped on the shoulders of new engineering personnel. She was killed during the Battle of Hollow Point in 2535.

Traditions
There were a number of unofficial holidays and events that were part of the Southern Cross ' calendar. By far the biggest and most important was the ship's Memorial Day. Taking place on October 24 each year - the day when the Southern Cross lost its first casualties in the Human-Covenant War - it encourages the crew to remember their fallen coworkers. The noticeboards were changed to display the names and faces of every crewmen the ship had ever lost, along with every fallen world the cruiser fought at. Later, a ceremony broadcasted from the bridge saw the lighting of candles, one for each year that the war dragged on. The entire event was designed to be short and non-intrusive, so it could be conducted even when under high alert status.

Started by Captain Eldar in 2529 was what would be affectionately called "the Collection", which were a series of makeshift museums that had been converted from disused storerooms. These contained everyday items taken from almost every planet the cruiser stopped at, encapsulating everything from alcohol to tourist merchandise to even media recordings. To get a sense of how varied the collection was, at one point it contained an intact suit of samurai battle armor, a Triad hypnosis portrait, and a signed edition of the autobiography Into The Unknown: The Story of Martinović's Voyages. At its height the Collection housed over 500 different items; however, between battle damage, thieving dockworkers, and simple deterioration from age, only a fraction of that number still remains aboard in an intact manner.

In a practice still done today, small portions of the Southern Cross ' damaged or worn hull would be privately sold or traded to sailors and interested individuals, under the belief that the fragment will grant the ship's luck to the owner. The Southern Cross was not alone in this practice, as it was fairly widespread at the height of the Human-Covenant War. Nowadays, the Victory Museum of Tribute recycles a portion of the cruiser's hull whenever it enters the drydock for repairs, which are made into sculptures that are auctioned off to fund its continued preservation.