The Fall of Reach, also referred as the Battle of Reach, was one of the largest engagement in the Human-Covenant War. Fought between the UNSCDF and the Covenant from July 25th to August 30th, 2552, the battle was regarded as one the largest and most decisive military defeat in space incurred by the human civilisation, even surpassing the military casualties from the Battle of Earth.
Though hailed victorious after the victorious naval battle overSigma Octanus IV, the UNSC Navy severely underestimated their extraterrestrial aggressors, whom managed to attach a tracking probe onto the UNSC Iroquois. When the Iroquois returned to Reach, the planet's presence — and its extent — was disclosed to the Covenant Empire. Unbeknownst to the UNSC officers, the Covenant siege of Sigma Octanus IV had already compromised the location of Reach; the artefacts recovered by Covenant's archaeology recovery units revealed all known nearby locations of similar artefacts around the system.
Prior to the Fall, the Covenant Empire despatched a pre-invasion force, the Third Fleet of Glorious Consequence, to Reach to assess the human's military strength and infrastructures along with available ancient artefacts that could be of use for the Great Journey. The force, with its preliminary objectives completed, deployed its ground forces and initiated the invasion by establishing several bases of operations. Though the UNSC managed to rid the preliminary invading forces from the planet, their effort was for naught as the rest of the Covenant invasion fleets had arrived.
Prelude to battle
The Covenant made considerable preparations before initiating the primary invasion. When the probe transmitted its reports, the Covenant's Council of Masters inspected the details and referred to the Council of Generals with a proposal of a joint-operation which involves crippling the human's defences and infrastructures.[note 1] This proposal laid out complex methodologies that had not worked effectively in past theatres, but necessary to avoid another disgraceful loss as such in Sigma Octanus IV.
The Third Fleet of Glorious Consequence was given this task by the Masters, having its battlecruisers and destroyers reassigned to other fleets and, for the purposes of keeping a low-profile, now composed primarily composed of picket ships and frigates.
On July 23rd, the picket ships of the Glorious Consequence arrived in Epsilon Eridani via slipspace, beyond the UNSC's monitored territories. Subsequently after their arrival, the ships diverted all known sensors used by the UNSC and established a secure entry point at the edge of the system, potentially masking any future slipspace arrival.[note 2]
1647 hours: Operation: NIGHT FALL commences. Noble Team executes a reconnaissance mission to gather intelligence on the amassing Covenant forces and occupied sites.
1822 hours: Operation: NIGHT FALL ended.
0800 hours: Battle of Viery commences: A massive joint UNSCDF force assaults Covenant forces in Viery.
1055 hours: Beta Team of SPARTAN-II Red Team (SII/B) assisted the UNSCDF force in defending acquired ground-sites from Covenant forces. UNSC communique informs the planetary forces of incoming reinforcements on the 14th.
0400 hours: Final preparations for Operation: RED FLAG commences.
0747 hours: Seven bases of operations established by the Covenant identified; evacuation of population centres initiated.
1137 hours: An increase of Covenant forces detected over the UNSC-reclaimed ground-sites, deployed by an orbiting Covenant supercarrier.
1248 hours: Operation: UPPER CUT commences.
1311 hours: Sword Base along with other population centres get severely damaged by Covenant's bombardment.
1447 hours: FermionRSO detects the incoming 116 Covenant vessels via slipspace near the second Orbital Defense Line.
1732 hours: Components of Epsilon Eridani Defense Fleet (reported at 62% strength) arrived near Csodaszarvas. The fleet assisted the planetary defenses against the Covenant invasion fleet. At this point, one Orbital Defense Platform has been disabled due to overwhelming Covenant forces.
The Covenant fleet, Fleet of Particular Justice, arrives at Reach. A total of 314 Covenant vessels exit slipspace and engage the Orbital Defense Lines managed by the remaining 18 Orbital Defense Platforms over Reach. The Orbital Defense Lines suffered severe afflictions due to overwhelming Covenant warships. The entire Epsilon Eridani Defense Fleet is at capacity of 66% strength.
Evacuation of population centres commences: SPARTAN Gauntlet, Echo and Red Team redirected to evacuation duties.
0732 hours: Deployment of Covenant dropships toward FLEETCOM HQ and the Orbital Defense Generators. Red Team redirected from evacuation duties to security of defense facilities.
1517 hours: The defense facilities are destroyed by Covenant forces. Orbital Defense Platforms are subjected to temporary power supply for the next 24 hours.
The entire Epsilon Eridani Defense Fleet (reported at 40% strength) gathers to launch a naval counter-offensive operation to counter the Covenant invasion. An additional 200 Covenant vessels arrived via slipspace and successfully disabled the Orbital Defense Lines.
The entire Epsilon Eridani Defense Fleet suffered severe casualties (reported at 12% strength). The surviving and slipspace-capable ships attempt to evacuate everyone from Reach.
The Covenant fleet crushes the remaining orbital defenses over Reach and split their fleet into two groups, one pursuing the scattered UNSC ships and the other beginning to glass Reach.
↑Separatist leader, Thel 'Vadam, provided the UNSC some details of past operations conducted by him while serving under the Covenant Empire. One of it was the Covenant invasion of Reach.
↑The arrival of the picket ships was not unnoticed by the RSOs; the probes recorded the arrival but was not able to identify the object. The report was filed but never explored until at the end of the Human-Covenant War