You'll be able to accept this side mission from the south west of Meridian Outskirts.
Navigate to Precipice Anchor
Once you've collected the mission, teleport back to Sanctuary and make your way over to the Navigation Console and adventure off to the Precipice Anchor.
Use drop pod
Upon arrival at the Precipice Anchor, head down to the bottom of the ship and use the drop pod to launch yourself down to complete the mission.
Eridian Proving Ground
Once you've completed the mission you'll now gain access to an Eridian Proving Ground, refer to the [Trial of Discipline] page for details on how to complete this Endgame activity.