Basically there are like 6 or so ledges way outside Midnight and they are solid for some reason, not sure why. But if you get enough power to launch to it you can land on it and explore. They look pretty small from inside the map but when you get up close and personal its quite the area to explore, at least for Halo 4 standard.
Yeah, it’s a pretty big area for Halo 4. Still nothing compared to Reach though. Breaking out of Spire was just a treat xP