The Maelstrom is a massive asteroid barrier that separates Guardian Space and the Forgotten Zone. It is the largest asteroid field in the universe. The Maelstrom's reach is infinte, making it impossible for anyone to fly through or around it without having the Lighthouse code which causes the asteroid field to be separated by an energy-tunnel projected by the Lighthouse.
The Maelstrom separates and connects the Forgotten Zone and Guardian Space. Within the heart of the Maelstrom lays the Lighthouse, which enables individuals to cross through into the asteroid barrier to either designations they choose.
It was later destroyed by the Anti-Monitor.