Unlike with other planets' challenges, the currently-active challenges for Io cannot be checked by going to bungie.net, clicking on the magnifying glass in the upper-right corner, and searching for "Io" - the planet's name is too short for the search engine to return results.
1. Area Infiltration
- Lost Sectors: [region name]: Loot a Lost Sector near [region name].
- Pyramidion Raider: Defeat 40 enemies around the entrance to the Vex Pyramidion.
- Io Scavenger: Gather [10 Phaseglass / 3 Phaseglass Spires]. [Harvest 10 Phaseglass objects / Obtain Phaseglass Spires 3 times from harvesting Phaseglass objects.]
- Treasure Hunter: Loot three Vex or Cabal supply caches.
- Event Horizon: Successfully complete a public event.
- Walk the Beat: Complete three Patrols. [Listed on bungie.net as Walking the Beat.]
3. Enemy Kills
- Scourge of the [enemy faction]: Defeat 75 [enemy faction] enemies.
- Cut Off One Head: Defeat a Vex Hydra.
- Dark Decimation: Defeat 3 Taken Centurions.