A method and system for an aerospace vehicle. A pulse of electromagnetic radiation is transmitted into the composite sandwich panel such that the composite sandwich panel is heated above an ambient temperature. An amount of infrared radiation generated in the composite sandwich panel is detected in response to transmitting the pulse of electromagnetic radiation into the composite sandwich panel using a time window selected to detect the amount of infrared radiation when the pulse of electromagnetic radiation heats the composite sandwich panel. The amount of infrared radiation detected indicates a level of moisture in the composite sandwich panel.