Threshold

Summary

Before its destruction, Alpha Halo orbited a large gas giant known as Threshold (Earth Survey Catalogue Number B1008-AG), anchored at the L1 Lagrange point between the planet and its largest moon, Basis. An extensive network of Forerunner gas mining and refinery stations was suspended in the atmosphere through a number of band orbitals, though only a handful remained active into the modern era.

While Basis is by far its largest moon, eleven other satellites orbit Threshold. These satellites have not been extensively surveyed, though all but two appear to either house some sort of Forerunner installation or are entirely artificial. The function that these outposts served remains unknown, but most evidence indicates they provided maintenance for Alpha Halo.

Locations

COLOSSUS - WAR GAMES MAP_SET/: 201-7

Similar to the mining facility which the once-heretic leader and now-deceased Sesa ‘Refumee took occupation of, the War Games map called ‘Colossus’ is a separate and distinct Thresholdian satellite. Acquired by scans conducted by the UNSC Red Horse in its survey of the area, and also later corroborated by human-Sangheili dialogues, this structure mined gas from the high above Threshold’s roiling ‘surface.’ The environments symmetry, scalability, and obstacles presented unique challenges to Spartans training in the War Games, and thereby became a favorite of fireteam leaders, particularly for objective-based combat simulations.