A guidance system for a missile performs a method for guiding the missile. The guidance system includes a target detector and a window between a target and the target detector. The window including a first pane, a second pane and a channel between the first pane from the second pane. Radiation from the target passes through the window including the first pane, the second pane and the channel to be detected at the target detector. A gas is transported through the channel between the first pane and the second pane to control a temperature of the window.