Terra Nova (Earth-5875)

"Terra Nova. Not quite home away from home when the the Office staked its claim."

- - Karl Bishop Weyland

Terra Nova was a lush human Outer colony, in the Iota Draconis system. It was home to the small settlement Freyja and an Office of Naval Intelligence base, mostly inhabited by UNSC personnel and their families. It was also home to ancient forerunner ruins, which were being studied by xenoanthropologists.

Ancient past
The planet which would be known as Walter was first colonized by the forerunner during the days of their ancient empire, where they used it as a studying ground. During the forerunner's war against the xenomorphs, the planet was seemingly used to investigate counter measures against the endoparasite, to no avail. After the firing of the Halo Array, many forerunner ruins were left behind in the planet's jungle and subterranean areas.

Human colonization
Terra Nova was colonized by humanity during Domus Diaspora in 2275, as part of the Outer Colonies. Rich in minerals, major sections of Terra Nova were then terraformed, and settlements such as Freyja were founded. The planet eventually underwent numerous economic difficulties in the decades leading to the Secession, but Terra Nova's survival through the First Contact War ensured it continued to sustain itself. On September 30th, 2547, the Office of Naval Intelligence closed Freyja's businesses to pan-corporate enterprise, reneging numerous co-development agreements, following the discovery of forerunner ruins on the planet. This later escalated in a major ONI effort to cover the purpose of a major facility they had built amidst the forerunner ruins, conducting research on the forerunners and xenomorph specimens it retrieved from Paraíso one year earlier.

Battle of Terra Nova
These xenomorphs were enslaved and used as test subjects to form a Keymind. The Keymind was eventually able to escape with the help of a lone and intelligent xenomorph, and quickly settled a hive within Freyja's Staten Refinery. The catastrophic outbreak led to the slaughter of most of Freyja's population, except for its synthetic administrator Katya, who was able to hide and warn the UNSC Marlow, the closest ship to the planet, about the mysterious alien attackers. Believing the aliens to be an unidentified Covenant species, the UNSC Marine Corps then deployed its 1st Battalion, 3rd Regiment to Terra Nova, to investigate. However, as soon as the Marlow arrived in the Iota Draconis system, it was shot down by a hidden CCS-class battlecruiser led by a group of Silent Shadow sangheili, who were in search of a Special Operations who had gone missing on the human world.

After a three-sided battle between the UNSC, the Covenant, and the xenomorphs, Terra Nova's settlements, laboratories, and forerunner ruins were unwillingly destroyed by the First Blade officer Dahr 'Voliree with a HAVOK tactical nuke in order to prevent the xenomorphs from escaping from the planet and spreading across the galaxy. After its loss, the Office of Naval Intelligence covered the event as being one of the many attacks by the Covenant, and had the UNSC prohibit any transit or approach to the planet.