Algolis

Algolis was a human colony planet. The planet possessed at least two moons.^[2] Algolis housed a relatively small civilian population and was home to some of the Office of Naval Intelligence's research and development projects for prototype weapons, including the HRUNTING/YGGDRASIL Mark I ADS.^[3]

Overview

The Office of Naval Intelligence's Section Three had facilities on the planet, to which several SPARTAN-II augmentation chemical precursors were sent without Dr. Catherine Halsey's consent, likely in order to be researched for Project CHRYSANTHEMUM.^[4]

Atriox, defying the Covenant on Algolis.

Main article: Algolis Invasion

The colony was attacked by the Covenant at some time before March 28, 2549.^{[Note 1]} During the battle, the planet's civilians were evacuated while Marines from the UNSC Marine Corps of Engineers made a last stand against Covenant forces. The UNSC destroyer UNSC Heart of Midlothian was en route to the planet to secure a powered armor before the facility was attacked. The planet's survivors escaped in transport ships to a UNSC frigate in orbit that carried them to safety.^[5]^[6] The battle also resulted in the formation of the Banished as well.^[7] Overall, it's unknown what happened to the colony following the battle.^[3]