Missile turrets used to rely on sensor towers to detect enemy units. However, by the GDC 2008 build missile turrets could detect by themselves. The sensor tower was canceled and in the WWI 08 build had the name changed to the radar tower. However, it has been brought back. The sensor tower has oscillated between being a detector and not a detector. In early May 2009 it was not a detector, but in the Seoul Ap-Gu-Jung, event from May 21, 2009 it was a detector. By November 2009, however, it had lost detection.