The FireMapper multispectral radiometer is being prepared for airborne deployment next year by the US Department of Agriculture's Forestry Service. The device, manufactured by Space Instruments Inc. of Encinitas, Calif., monitors long-wave infrared spectra to peer through the smoke from forest fires and see where the flames really lie. At about 25 lb, the uncooled FireMapper will be carried aloft by a light Piper Navajo to 1500 ft, from where it will construct temperature maps with a resolution of 2.7 ft in the infrared. FireMapper simultaneously images at three wavelengths in the infrared (8 to 12.5 µm wideband, and 8.55 and 11 µm) and in two visible bands. It has uses in ecological monitoring as well as in other forestry applications, such as the detection of blight, since it can resolve individual trees from its mission altitude. The project is under the supervision of Philip Riggan of the Forestry Service's Pacific Southwest Research Station in Riverside, Calif.