Keyes Loop

The "Keyes Loop", as drawn by Captain Keyes for Dr. Halsey.

"Sir, that was the most brilliant maneuver I have ever seen."

— Lieutenant Hikowa to Commander Jacob Keyes.

The Keyes Loop was a famous space tactical manoeuvre first executed by then-Commander Jacob Keyes at the Battle of Sigma Octanus IV in 2552. The result was one of the rare naval victories achieved by the UNSC over Covenant forces, and it led to Keyes' promotion to Captain by Admiral Stanforth. It also provided a badly-needed morale boost to the whole fleet.

Overview

Background

At 0300 hours on July 17, 2552, the remote scanning outpost Archimedes detected the signature of a Covenant fleet in slipspace transit to the Sigma Octanus system. These findings manifested in Archimedes' logs as an unusally large single object in slipspace, though were quickly determined to be a tight formation of Covenant starships by officers aboard UNSC Iroquois. Commander Jacob Keyes relayed these findings to UNSC Fleet Command (FLEETCOM) to alert them of an imminent incursion in the system, with Vice Admiral Michael Stanforth's Battle Group Leviathan mustered to respond to the attack. However, Leviathan were still in the Epsilon Eridani system and would take several hours to arrive at Sigma Octanus - well after the Covenant attack would be finished.

At this time, the UNSC's defensive presence at Sigma Octanus was light, consisting only of three light warships: the frigates UNSC Allegiance and UNSC Gettysburg, and the Halberd-class light destroyer Iroquois. Of these, only Iroquois was in orbit of Sigma Octanus IV itself, with the frigates located further out-system. By the time the Covenant fleet, consisting of a carrier, two frigates, and a light destroyer, arrived over Sigma Octanus, both frigates were an hour away from arriving to assist. This left Iroquois the sole ship on station to respond to the attack against a force that would typically be considered a challenge for seven destroyers.

The battle

The Covenant fleet emerged from slipspace between Sigma Octanus and Iroquois and approached the planet in a formation consisting of the carrier in lead, with the destroyer trailing and the two frigates following. Iroquois engaged its fusion drives on a hard burn, locked on an intercept course with the destroyer. Upon detecting Iroquois the two frigates broke off from the formation to intercept the human ship, each firing a single plasma torpedo at the destroyer. Keyes counted on this to aid in his planned manoeuvre by using the plasma torpedoes against the Covenant. When the torpedoes approached Iroquois the destroyer engaged its emergency thrusters to sidestep them, with the torpedoes now trailing the UNSC destroyer as it closed in on the Covenant destroyer. After bypassing the Covenant frigates, Iroquois fired a single Shiva-class nuclear missile aft for later use.

At the last second, just before Iroquois collided with the Covenant destroyer, the ship did a last-minute course correction that narrowly grazed the larger vessel's energy shielding. The collision severely damaged Iroquois and tore through 2 metres (6.6 ft) of Titanium-A armor plating and breached through every bottom deck; however, the trailing plasma torpedoes were unable to correct themselves for the sudden manoeuvre of their target and, consequently, hit the Covenant destroyer instead. A heavy salvo of Archer missiles fired by Iroquois were then able to finish off the now severely-weakened and vulnerable Covenant ship.

With the momentum built up during the first phase, the Iroquois performed a slingshot manoeuvre around the planet (something Catherine Halsey suspected was inspired by tactics employed by Vice Admiral Preston Cole). Once safely away, the nuclear warhead deployed earlier was detonated, completely draining the shields of the two frigates. Having completed its orbit, Iroquois resumed its attack and destroyed the two frigates with two heavy Magnetic Accelerator Cannon (MAC) rounds and hundreds of its remaining Archer missiles. Its escorts destroyed, the carrier disengaged and escaped from the system, with Allegiance and Gettysburg tailing it. Before leaving, it dropped 34 dropships and a stealth ship to continue the ground assault. Later, the carrier hailed the rest of the attack fleet to Sigma Octanus IV.

Aftermath

Commander Keyes' victory against the Covenant was a rare naval victory for the UNSC at a point in the Human-Covenant War where the UNSC was on its last legs. Almost immediately, personnel across the fleet nicknamed his tactic the "Keyes Loop", a name which was picked up by ONI Section Two for propaganda use. Despite this, Keyes felt that his tactic had been suicidal and, had it been suggested by one of his students at Officer Candidate School, he would have graded it a C-.

In the aftermath of the engagement, the Iroquois was damaged to the point that it required almost a complete overhaul. Fifteen percent of the electronics had to be replaced due to EMP burnout from the Shiva. Eight magnetic coils had to be replaced as well, disabling the MAC for a time. One of the emergency thrusters had to be refilled. The engines' vents had fused together due to extreme heat, and would need a complete overhaul to get them fully operational. Even after refit aboard the UNSC Cradle, only 50% power was available. Finally, and most dangerously, all of the bottom armour and bottom decks that had been eroded by the Covenant destroyer's shields were replaced. Commander Keyes was offered by the Cradle to repaint the Iroquois, but he declined so that he would never forget the ship's battle scars.

Overall, the victory bought time for Battle Group Leviathan to arrive at Sigma Octanus IV, where hours later they would fight a second battle against the Covenant and achieve a second rare win for humanity.

List of appearances

• Halo: The Fall of Reach (First appearance)
• Halo: Reach
  • Dr. Halsey's personal journal
• Halo: Combat Evolved Anniversary (Indirect mention)
• Halo Mythos (Mentioned only)