Operation: HELLSCAPE

One of the furthest colonies left by 2549, Pavo Prime in the Delta Pavonis system was located 19.9 lightyears from Sol. One of the largest producers of titanium after Reach, Pavo Prime was an asteroid colony kept running by a seventh generation "smart" AI on loan from the UNSC Navy - in exchange, the colony provided the Navy with free access to its shipyards, repairing warships and commercial freighters. After the fall of so many vital areas of production, the UNSC deemed Pavo Prime a location of strategic importance, attaching a permanent defence taskforce to the system.

Operation: HELLSCAPE is the designation given to the battle to defend the system against a Covenant invasion in 2549. Arriving in-system on September 13th, 2549 after information passed by the Prophet of Acquisition promised a cache of relics in the system, elements of the Fleet of Enlightened Benevolence engaged Taskforce Pericles and moved swiftly, destroying three quarters of the formation and invading the asteroid colony of Pavo Prime with three legions of Covenant troops. A counter-attack by the UNSC 30th Fleet routed the occupation forces, and superior numbers forced the Covenant ships to retreat with the relics they had excavated, though a number fell into UNSC control. Though nine thousand and sixty six civilians had been killed during the invasion, with another two thousand Marines KIA, the Covenant suffered much higher casualties, one of the few victories in the Human-Covenant War to claim such a statistic.

Invasion
Pavo Prime was one of the last major suppliers outside of Epsilon Eridani - in addition to its large deposits of titanium, ferrous iron, osmium and iridium, it was also home to the Pavonis Shipyards, one of the only shipyards permitted for the private sector by the UNSC Navy after the Insurrection. The material wealth of Pavo, as well as the important personnel and infrastructure, warranted a small defensive taskforce to engage any Covenant threats, and at least buy time to evacuate the colony and send off a distress alert to UNSC forces. The frigates Waikato, Boston and Ulysses S. Grant, as well as the heavy destroyer Pericles formed the bulk of Taskforce Pericles, though civilian-operated armed yachts and gunships would supplement their patrols. The shipyards themselves, while still privately owned and operated, had been converted to produce military warships in 2534, and had already produced thirty frigates, with another six hulls already laid.

As such, when a Covenant taskforce entered the system in 2549, prevention of the system's infrastructure was a key priority for the UNSC, and Taskforce Pericles was ordered to hold off the invaders until at least the shipyards had been evacuated of key personnel. The ship they departed on, the UNSC Corvette Howard Hughes, jumped according to the Cole Protocol, reoriented, and made it to Reach by September 27th. In the meantime, Taskforce Pericles coordinated a series of hit-and-run operations against the enemy taskforce, attempting to make use of every advantage they had at their disposal. One enemy cruiser and two frigates were lured near the other side of the Sykes Asteroid Belt, destroyed as a Shiva nuclear missile detonated, spraying them with shrapnel - the frigates were destroyed, though the cruiser survived with only superficial hull damage. The UNSC Waikato was rigged as a fireship by its AI, Tinuviel, transferred to the Pericles, and rammed into the heart of the taskforce and detonated remotely, destroying another two ships. Ultimately, however, Taskforce Pericles was unsuccessful in its attempts - the Boston was lost with all hands on September 17th, the Waikato was destroyed on September 21st, and the crew of the Ulysses S. Grant was forced to abandon ship after catastrophic hull damage on September 23rd, the lifepods recovered by the Pericles. Unable to continue the delaying action, the Pericles withdrew to bide its time until an opportune moment presented itself.

Their actions had allowed the civilian populace of Pavo Prime enough time to retreat to secure bunkers, but they were still ill-equipped for the ensuing Covenant invasion on September 24th, with the major population centres quickly falling to the Covenant. An attempt was made by the occupiers to round up survivors for interrogation, searching for anyone with knowledge of "relics" dug up on the asteroid colony, but it quickly became apparent to the Covenant commander, Fleet Master Kuna 'Tsunamee that the humans knew nothing about their reasons for arriving at the colony, and they were ordered executed. Hunters and Drones were ordered into the asteroids tunnels in the hopes that they would be able to flush out the remaining civilian holdouts, but the narrow corridors and easy access to mining equipment meant that the humans were able to make successful stands, caving in sections and retreating ahead of the Covenant advance. By October 4th, the colonists were in a bad way, running low on supplies and ammunition, and running out of tunnels to fall back to.

Cavalry
The arrival of the UNSC 30th Fleet was timely, and in the opening hours of the orbital battle for the colony the UNSC destroyed five destroyers, leaving the Covenant force at only five ships, including the cruiser Purity of Spirit and the carrier Enlightenment, the latter of which was damaged as the Pericles rejoined the fight, firing its remaining missile salvoes and MAC rounds in a blaze of glory that was rewarded by the crippling of the Covenant flagship. Dropping reinforcements in the form of an ODST battalion and three Marine regiments, the UNSC quickly set about repelling the Covenant from the surface of the asteroid, using the same tunnels that had proven so troublesome for the Covenant to trap the Hunters and Drones still combing the tunnels with high explosive. The last escape tunnels were secured by the 427th Marine Regiment, allowing the surviving men, women and children to escape, evacuated by the UNSC Supercarrier Ark Royal and the smaller carriers Invincible and Agamemnon. ODST forces quickly captured key Covenant forward operations bases, supported by SPARTAN-II Indigo Team, capturing the base set up near the Alcmaeon Arcology, and Marine forces pushed the Covenant out of the tunnels. By October 17th, the Covenant was in total route, with only the Kr'Rana Legion still in fighting shape - the other two were either destroyed, or reduced to a third of their original size. Managing to fallback to their last stronghold on the planet, the Kr'Rana Legion managed to recover the Pavonis Artefact, the entire point of the invasion, and fall back to the Purity of Spirit for withdrawal. Volunteering to stay behind, what was left of the Utqarz and Yuthacan legions staged a last stand to allow their Kr'Rana brothers to get the relic to the Prophet of Acquisition. The relic would later point the way to Minorca, a fabled Labyrinth world.

Aftermath
Out of the nineteen thousand colonists who had inhabited the asteroid colony, more than half were killed by the invasion, most of these made up of elements of the Pavonis Militia who held ground where they could to allow noncombatants to get into the tunnels, what they thought to be safety. More were killed as the Covenant followed them in, not interested in the mineral wealth fo the planet but very keen on exterminating what they percieved to be cornered vermin. Of the nine thousand colonists who survived, most were women and children, as well as the elderly. Nevertheless, the safe evacuation of nine thousand civilians was a major propaganda coup for the UNSC, and the failure of the Covenant fleet to fully capture the planet and glass it afterwards was a significant blow against Fleet Master 'Tsunamee's standing, resulting in the start of a fall from grace that would ultimately see Ship Master Zuro 'Xoramee succeed him at Minorca. The devastation of two Covenant legions with comparatively few UNSC losses was also a triumph for the UNSC at a time when any good news was welcome.

Remarks

 * "Have you ever seen trapped miners backed into a corner? Apparently the Covenant hadn't, because they thought it was a good idea to follow them into the tunnels. After a few cave-ins and explosive ambushes, they started regretting that decision - we made sure of that."
 * "The slaughter of the human civilians was...regrettable. Even 'Tsunamee felt ashamed of killing those who had done nothing to us or our honour, but he revered the Prophets. He would have been devastated to learn of the Schism - perhaps it is for the best he perished at Minorca, a good death in battle."
 * "It used to be a lump of rock. The corporations built it up - technically it was never a colony. They kept it registered as "private assets plus staff." I'm glad the UNSC decided to take a vested interest in us, because no CEO back on Earth would have. The Navy had to pressure them to even put up the patrols."
 * "We returned there in 2554 - a rogue Drone colony had occupied it, using the pre-existing tunnels to build their hive, hoping the Covenant would ignore it. We let them have it - ONI wanted to study Drones in their "natural habitat", and the Elites wanted to see if they were interested in an alliance. Turns out they were very interested."