Battle of Orchid IV

The Battle of Orchid IV was a short but bloody engagement between the United Nations Space Command and the Covenant Empire, occurring in 2539 on and above the planet Orchid IV. UNSC forces were caught by surprise by Covenant vessels, who approached the system while the defenders organised themselves. The battle was a tactical defeat for the UNSC, who took heavy losses while inflicting few on the enemy; however, in the objective of evacuating civilians from the world, they were partially successful.

The Battle
At 06:56 system time on August 6th, an outgoing agricultural freighter near the edge of the system reported detecting multiple unidentified vessels exiting slipspace. The vessel was destroyed before it could jump to safety, and as soon as this event was relayed to local command at Orchid IV, the military began mobilising and civilians started to be evacuated. The vessels were confirmed as a Covenant fleet as they passed a spatial weather monitoring station on the system's outermost satellite.

By 11:00 the following day the Covenant vessels had moved within firing range of the UNSC fleet, which retreated to the far side of the planet. Almost half of the planet's 300,000-strong population had been evacuated by this point, with just two large groups of evacuation transports left to leave. The ten Covenant ships launched an invasion force of 17,000 troops from orbit, which descended into the planet's atmosphere; Marine air and ground assets engaged and destroyed roughly 20% of the force before they made landfall (approximately 4,000 troops). Throughout the August 7th Covenant forces pushed back the Marines and Militia blocking the spaceports in the cities; By 15:00 the second last wave of transports was full to capacity and escaped the planet, missing the Covenant fleet and taking few losses. The defending forces fought throughout the night and into August 8th to prevent the Covenant reaching the last wave of transports, taking severe casualties. The last wave of transports were cleared for departure at 06:00 of that morning, with the Covenant fleet now positioned to completely eradicate it in the escape.

The UNSC fleet now faced the Covenant armada and charged, opening fire with Magnetic Accelerator Cannons and Archer missiles, and partially drawing their attention away from the civilian ships leaving the planet's atmosphere. One Marathon-class Cruiser and three UNSC Frigates covertly entered the planet's atmosphere and recovered the UNSC's military force and a small number of civilians, while the larger force of two Marathon-class Cruisers, four UNSC Frigates and four UNSC Destroyers engaged the Covenant vessels. The vessels departing the planet escaped with a loss of 133 civilian vessels and one UNSC Frigate; the ten vessels charging the Covenant were all destroyed.

As a result of the UNSC Navy's action, the last wave of civilian transports, totalling 214 ships and 110,000 civilians, had a chance to escape; only 161 of these took off and reached orbit without being destroyed by Covenant ground or air troops; a further eighty were destroyed by Covenant Navy fire. The remaining 81 vessels jumped to safety, saving 41,250 lives. In total, almost 300,000 civilians escaped the system safely, with a cost of almost 90,000 lives; most of these casualties occurred during the last wave of the evacuation. UNSC Navy losses were almost entirely from the diversionary attack on the Covenant vessels, which resulted in the destruction of all ten ships. Ground forces took serious losses while holding off the Covenant and preventing them reaching urban areas; the vast majority of surviving units were evacuated by a Marathon-class Cruiser and three UNSC Frigates, who did this under cover provided by the rest of the Navy; however, one of these Frigates, fully laden with embarked troops, was destroyed before it could escape the system.

Following the battle, the ten Covenant vessels presumably glassed the world and abandoned it; in 2545 a UNSC Prowler conducting reconnaissance found the planet in such a state.