Battle of Sector 001

The Battle of Sector 001 was a confrontation between the United Federation of Planets and the Borg Collective in 2373, when a Borg cube attempted to assimilate Earth. Although the battle resulted in significant casualties for the Starfleet forces, the fleet was able to destroy the Cube. Unlike the infamous Battle of Wolf 359 six years before, Starfleet proved to be more prepared to fight the Borg. The fleet, though outgunned, ultimately managed to successfully destroy the Cube, partially due to Captain Jean-Luc Picard's tactical knowledge of the Borg.

Prelude
The second major Borg incursion into Federation space began shortly before stardate 50893.5, when the colony on Ivor Prime was destroyed. Nearby Deep Space 5 detected the attack, and long-range sensors detected a single Borg vessel. Vice Admiral Hayes was immediately informed when it was determined the cube was on a direct course for Earth. Hayes contacted Captain Jean-Luc Picard aboard the USS Enterprise-E, who was already aware of the Borg presence in Federation space and felt he should be part of the response force. However, Hayes believed that Picard's previous experience with the Borg, in particular his assimilation into the Collective as Locutus, would add an "unstable element to a critical situation". Despite Picard's protests to Starfleet Command, the Enterprise was ordered to patrol the Romulan Neutral Zone, while a Federation fleet mobilized in the Typhon sector to intercept the Borg cube before it reached Earth.

The Battle
The cube engaged the fleet soon after. The conflict was broadcast on Starfleet frequency 1486, and was monitored by the Enterprise. Approaching at speeds exceeding warp nine, the cube broadcast its familiar litany:

'"We are the Borg. Lower your shields and surrender your ships. We will add your biological and technological distinctiveness to our own. Your culture will adapt to service us. Resistance is futile."

The fleet opened fire, but to minimal effect. The defense perimeter was quickly shattered, with numerous ships being lost, as the cube continued on unrelentingly towards Earth. The surviving ships, including the USS Defiant and the USS Bozeman, assaulted the cube all the way to the Sol system. Realizing that the battle was not progressing well, Picard ordered the Enterprise-E back to Earth in violation of his orders. It has been noted that from the point of the initial Borg attack to a distress call being sent, the attack lasted just over forty seconds.

By the time the Enterprise arrived in Earth orbit, a large portion of the fleet had already been lost, including Hayes' flagship. However, by this point in the battle, the fleet had succeeded in dealing heavy damage to the cube's outer hull, causing fluctuations in their power grid. The Defiant, commanded by Lieutenant Commander Worf, had been heavily damaged and was preparing to ram the cube when the Enterprise-E arrived, distracting the Borg long enough to transport the Defiant crew off their stricken ship as its life support failed.

Picard, taking advantage of his residual link to the Collective, took command of the fleet and ordered all weapons to be targeted on a seemingly non-critical point on the cube. The resulting barrage destroyed the cube, though the explosion also claimed several nearby starships.

Aftermath
Shortly before its destruction the cube launched a small spherical vessel from its interior – a type of Borg vessel not seen before. The sphere headed straight for Earth, with the Enterprise in hot pursuit. The sphere began generating chronometric particles, forming a temporal vortex. The sphere disappeared inside the vortex near the boundary of Earth's atmosphere, traveling back in time to 2063 and disrupting First Contact. As the Enterprise was caught in the temporal wake of the vortex, its crew saw an assimilated Earth with a drone population of nine billion. The Enterprise followed the sphere into the past, and was able to restore the normal version of history before safely returning to the 24th century. This time travel event was described by Seven of Nine as an example of the pogo paradox. Starfleet's losses in the battle were comparable to the earlier fleet action at Wolf 359. The destruction of so many ships left the remaining fleet stretched thin across the quadrant, as was later rued by Captain Benjamin Sisko shortly before Dominion forces passed through the Bajoran wormhole into Cardassia, and would prove of even greater significance following the later outbreak of hostilities.

In addition to the losses inflicted by the Dominion, the casualties due to the Borg also caused a policy change within the Federation Council and the admission of new members was accelerated, as with the Evora, whose homeworld was declared a protectorate in 2375, the year after they achieved warp drive. First and foremost, however, the Council tended to act more questionably ethically, even compromising the principles upon which the Federation was founded during the Ba'ku incident.