I wasn't doing any mission, just flying around in my Pell Silverbolt 6, exploring the game map, and ended up in this weird place on a fairly large island in north-west corner of the map. It has these towers with radar domes on top and one of these towers is HUGE. When I climbed to the top of it I found this room with something spinning inside that I assume is some kind of generator. The place was heavily guarded by enemy soldiers, so I assume it's important. However when I used my timed explosives on the spinning thing, it didn't destroy it (unlike with other generators that are destroyable). And when you point a weapon at it, it doesn't display a bar indicating that it has a health/damage property (so it appears to just be background imagery of some kind rather than something you can interact with or destroy). Any idea what it is? I've embedded a screenshot of it here for you to look at.