Thermal Infrared Spectrometers for the Polar Radiant Energy in the Far-Infrared Experiment (PREFIRE)

The Polar Radiant Energy in the Far-InfraRed Experiment (PREFIRE) was selected by NASA to fly two miniaturized Thermal InfraRed Spectrometers (TIRS) capable of distinguishing the spectral signatures of surface and atmospheric properties in Earth's polar regions. A trade study examining spectral sampling as well as separation of cloudy and clear scenery at 20 km scales highlighted the possibility to utilize ambient (uncooled) detector technologies in a miniaturized spectrometer that could facilitate low-cost and rapid access to space. This work describes the design, implementation, testing and performance of two TIRS systems that feature the novel joining of compact thermopile array technologies with concentric imaging spectrometry methods. The TIRS systems presented here each have 2.7 kg mass, draw 4.3 W power, and provide spectral resolution of 1.71 $\mu$m below 35 $\mu$m sampled at 0.86$\mu$m increments.