It's hard to explain exactly where this is, but I was exploring and saw a "cave" entrance low on the terrain and thought maybe it was a tunnel to a hidden item. It turns out the "cave" puts you under the terrain and if you jump off from the "cave", it just respawns you at the entrance of the "cave" and everything else is too high to jump to. If you blow yourself up while under the terrain, it just respawns you under the terrain. This is just a warning to everyone because I doubt Bungie will fix this. There really should be a spawn point, like a landing pad, added at the entrance to the quest for when we get stuck. At the very least, spawn us at the entrance or someplace safe when in this quest. I ended up having to leave and go back to the tower to get unstuck.