A method and system for detecting moisture in a composite sandwich panel for an aerospace vehicle. A pulse of an electromagnetic radiation beam is beam steered to the composite sandwich panel. The pulse of the electromagnetic radiation beam has a number of wavelengths that is absorbed by water molecules. The timing of the pulse of the electromagnetic radiation beam is synchronized to heat the composite sandwich panel with a time window in an infrared detector system to detect an amount of infrared radiation. The amount of infrared radiation in the composite sandwich panel is detected within the time window for the infrared detector system when the composite sandwich panel is heated by the pulse of the electromagnetic radiation beam, wherein the amount of infrared radiation indicates a level of moisture in the composite sandwich panel.