Io

"Io was the last place visited by The Traveler, and the site of great interest to both humanity and the timeless Vex machines. The Red Legion, too, now seek to unravel the secrets and power of this place, gouging at the surface, seeking to uncover new sources of power to aid in their quest to dominate our worlds. It is up to you to protect this place, and preserve its great legacy."

- Website description

Io (also called Jupiter I) is one of the four major moons of Jupiter.

Overview
In the final days of the Golden Age the Traveler was in the midst of terraforming Io when it detected the Darkness approaching; abandoning the moon as it fled to Earth. As a result of this, the Ionian climate and geography do not support traditional agriculture, meaning that some remnant of Io's original atmospheric composition prevented the full growth of plants. Echo Mesa, a mountain on Io, has become a popular pilgrimage site for Guardians. The Mesa overlooks a crater where the Traveler left behind a mysterious city-like structure.

One of the legends of the Nine state they are some of the original Awoken transcended to mental form and live inside the Jupiter-Io.

Locations

 * Echo Mesa
 * Javelin-4
 * Lost Oasis
 * Grove of Ulan-Tan
 * Spine Burrows
 * Terrabase Charon
 * The Wraith Mines
 * The Rupture
 * Aphix Conduit
 * Pyramidion
 * Sanctum of Bones
 * The Endless Gate
 * Giant's Scar
 * Excavation Site II
 * Warmind Vault JYS-2

List of appearances

 * Destiny
 * Age of Triumph
 * Destiny 2