The "ring derelict" is just a small part of the large debris field of the "Kharam Wreck" in one of the multiplayer maps of the same name in the demo. We don't know whether this structure will also appear in the single-player campaign. In the game files, this object is labeled "sajhulk" (as in "Sajuuk Hulk"), so it may be an obsolete model designed for the single-player campaign, and recycled for this multiplayer map. The ring-shaped portion of the debris array is one of two massive turrets. It's the more or less same turret that appeared on the old version of the Vaygr Red Assault Frigate in the E3 2001 build of the game, but scaled way up.

The "engine" portion of the wreckage also appears in the Karos Graveyard in the "Dreadnought Berth" Mission 08.