The entrance to the depot would likely have been in Anchorhead, but I can't even find a false doorway there that's shaped anything like that entrance. This looks like it would require areamodel editing to restore.
While looking around Anchorhead, I did find something else. The spaceport-like building that's to the right of the Dune Sea gate has some actual working doors behind its two false doors (one regular Anchorhead door and one docking bay one). I found this out by using a door-opener armband I put together and trying it on all the doors that wouldn't open- I head a door opening behind the fake ones. Maybe disection of the areamodel will yield clues to a removed areamodel section.