Massacre at Eridanus Secundus

The Massacre at Eridanus Secundus was a minor event in the Human-Covenant War that ultimately resulted in the destruction of the Eridanus rebels. It is most notable for the involvement of the Gettysburg-Ascendant Justice and Dr. Halsey's kidnapping of Kelly-087.

Spartans and Colonel Watts
In 2525, the Spartan-II unit's first assignment was to infiltrate the Eridanus Rebel's base and capture Colonel Robert Watts. The extraction component of the mission did not go smoothly and they were forced to kill several rebels and destroy the base's hangar. Of the 5 members of the team that were involved in that mission, 4 participated in this battle including John-117 who suggested the location.

Raid of Reach and Earth
During the Raid of Reach, Cortana intercepted transmissions between Covenant forces that indicated that the Covenant were planning on attacking Earth. They intended to rendezvous at the Unyielding Hierophant before finally attacking the human homeworld.

However, the Raid of Reach and the subsequent battle in the slipspace anomaly took them well beyond UNSC controlled space and severely damaged the Gettysburg-Ascendant Justice. Looking for a place to acquire repairs, John-117 recalled his earlier mission to the Rebel base and suggested it.

The crystal
The Forerunner crystal that was found on Reach and caused the slipspace anomaly posed a problem. While most slipspace movement could go undetected, the crystal sent out large doses of radiation that could be detected by the Covenant, effectively allowing them to track its movements. As such, the arrival of the Gettysburg-Ascendant Justice in the outer reaches of the Eridanus System spelled the doom of the Eridanus Rebel base.

Scouting patrol
After negotiating a meeting, which involved Vice Admiral Danforth Whitcomb blowing up another asteroid that was similar to the rebel base to force Governor Jacob Jiles to allow him and his staff entry to the base, Whitcomb warned Jiles that the Crystal meant that the Covenant would soon be arriving. Governor Jiles had just asked for proof of this claim when a Covenant cruiser emerged from slipspace. After quickly assessing that both sides didn't have nearly the armed capabilities that they initially thought, Vice Admiral Whitcomb tried the only solution available to him - the firing of a plasma turret. However, the plasma cannon's magnetic coil failed, making the plasma blast shoot straight into the Gettysburg's hull rather than at the Covenant warship.

It was suggested by Spartan-117 to try using the magnetic coil on the Gettysburg to direct plasma from the Ascendant Justice. This worked and successfully destroyed the Covenant Cruiser, but at the cost of destroying the turret that had fired the shot.

However, the scouting report proved that a Covenant fleet was coming and Governor Jiles agreed to help the UNSC forces. With the help of the rebels, they began repairs on the two warships.

The commandeering
Dr. Halsey, who had spent large portions of her career wrestling with her guilt, had decided to pursue her own agenda to try and save the Spartans. To this end, she sedated Kelly-087 and gave the Forerunner Crystal to Corporal Locklear with explicit instructions to destroy it.

With the Corporal's help, she was able to move the Spartan onto a Chiroptera class vessel which she then used to flee the system. This move frustrated both Governor Jiles, who felt it was a betrayal of trust, and Vice Admiral Whitcomb.

The main force
However, neither were given much time to complain about the matter, as a large Covenant fleet arrived in system shortly after the Doctor's departure. Initially, 2 warships entered the system, prompting the coupled Gettysburg-Ascendant Justice to leave the Rebel base, though without the evacuees on board.

By the time they were clear, a total of thirty Covenant warships had entered the system from three separate vectors. Whitcomb, feeling his duty was to Earth, not the rebels, ordered an immediate retreat to slipspace, leaving the helpless rebels to their doom.

Before departing, Corporal Locklear destroyed the Forerunner crystal, but underestimated the crystal's latent energy, and was killed in the process.

Rebels
It is assumed that the rebels were destroyed by the Covenant forces after the retreat of the Gettysburg-Ascendant Justice. No mention is ever made of any refugees on board the Gettysburg-Ascendant Justice.

Operation: FIRST STRIKE
The Gettysburg-Ascendant Justice would take a detour to the Covenant rendezvous by Unyielding Hierophant in Operation: FIRST STRIKE, eventually annihilating the vast majority of the fleet.

Dr. Halsey and Kelly-087
The Doctor and Spartan would eventually wind up over the planet Onyx during the Battle of Onyx, a battle they would play a major role in. They would eventually be joined by several other survivors from this battle.

Gettysburg-Ascendant Justice
It was shown that despite the rebels repairs, the Ascendant Justice was in terrible shape from all the damage it had taken. The Gettysburg, already in bad shape from the Battle of Reach was in likely the same shape as the Ascendant Justice though this wasn't clear. Thanks to the rebels repairs, the Ascendant Justice was able to put up a fight in Operation: FIRST STRIKE and helped destroy a Covenant fleet. The Gettysburg was rendered habitable and was able to return to Earth after the battle.