A multi-path, broadband infrared light source, foreground, and hyperspectral infrared imager are set up opposite each other with a towed airborne plume simulator burner installed in the High-Speed Fan Facility shooting a blast of fire and smoke between them during testing of the missile plume transmittance measurement system from Physical Sciences Inc. Arnold Air Force Base, Tennessee, May 12, 2022. Another set of light source and imager were also set up at a different angle to complete the measurement system. (U.S. Air Force photo by Jill Pickett)