Skirmish at Iophon

The Skirmish at Iophon was a minor battle between the United Nations Space Command Navy and the . The engagement occurred in 2540 when a UNSC and a Covenant vessel encountered each other and boarding action took place between them. Although the UNSC prevented the Covenant from coming into contact with the planet Iophon, the event caused its subsequent abandonment as its location was compromised.
==The Battle==
The confrontation began as the Marathon-class cruiser UNSC Absolution was conducting patrol on the outskirts of the system, with a portion of the 65th Marine Regiment embarked. While doing so it encountered a lone ; the vessel's commander, Henry Ward, was left with no choice but to engage or face certain destruction. The Covenant vessel quickly disabled the cruiser with plasma torpedoes and deployed boarding craft, presumably to obtain Absolution's navigational data. The ship's embarked contingent of Marines from the 65th Marine Regiment waged a protracted battle in the confines of the vessel. This long and bloody close quarters battle on board the vessel saw the Marines and Navy crew take heavy casualties while slowly losing control of the ship. Absolution's primary communications array was disabled shortly after it called for help; the Covenant concealed themselves in the tight confines of the vessel and set about picking off crew. The Marines barely thwarted an attempt by the Covenant infantry inside the vessel to vent its atmosphere (and occupants) into space, thus enabling further troops from the destroyer to board and retrieve navigational data. Shortly after this, internal communications were disabled; Ward prepared the ship's self-destruct as a final precaution, which would engulf the nearby destroyer as well, and rule out any chance the Covenant might find the location of other Human colony worlds. 
Before this was necessary, however, reinforcements from Iophon in the form of five Halberd-class destroyers closed with and destroyed the Covenant vessel, deploying additional Marines to Absolution and ending the costly firefight. Though the Divinity-class destroyer was defeated, it destroyed two destroyers before it succumbed, and also broadcasted an emergency transmission into space, presumably signalling its position. The local commander, Rear Admiral John Douglas, was authorised to begin abandoning the planet. Five days later, a probe left behind in the system, before it was destroyed, reported that at least three dozen Covenant vessels slipped into the system and moved towards the planet, apparently in glassing formation.