A shipboard illuminator is an RF signal that bounces off a target, Raytheon weapons developers have explained. The antenna in the nose in the guidance section [of the missile] sees the reflected energy and then corrects to intercept that reflective energy, the Raytheon official added. The emerging missile has an "active" front end, meaning it can send an electromagnetic signal forward to track a maneuvering target, at times without needing a ship-based illuminator for guidance. "The ESSM Block 2 will employ both a semi-active and active guidance system. Like ESSM Block 1, the Block 2 missile, in semi-active mode, will rely upon shipboard illuminators," Navy spokesman Dale Eng, Naval Sea Systems Command, told Scout Warrior in a written statement. Also, the missile is able to intercept threats that are close to the surface by sea-skimming or diving in onto a target from a higher altitude, Navy officials explained.