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The NPOESS Aircraft Sounder Testbed - Interferometer (NAST-I) is an airborne infrared interferometer maintained and operated by NASA Langley Research Center (LaRC). It uses Fourier transform spectroscopy to provide measurements of brightness temperature and radiance. NAST-I operates within the spectral range of 3.7-16.1 µm and has a spectral resolution of 0.25 cm-1. It has a spatial resolution of 2.6 km and a cross-track swath width of 46 km at a flight altitude of 20 km. A complete scan period for NAST-I takes around 12.2 seconds.

The NPOESS Aircraft Sounder Testbed - Microwave (NAST-M) is an airborne microwave radiometer maintained by the Massachusetts Institute of Technology (MIT). It measures brightness temperature which can be used to retrieve water vapor profiles in the atmosphere. It consists of two radiometers with one operating across 8 channels between 50-57 GHz and the other operating across 9 channels at 118 GHz. In 2003, NAST-M was upgraded with two additional radiometers operating at 183 and 425 GHz to improve water vapor retrievals and the detection of small hydrometeors. NAST-M has a spatial resolution of 2.6 km and a cross-track swath width of 100 km at a flight altitude of 20 km. It has a typical integration time of 100 ms.

The Far Infrared Sensor For Cirrus (FIRSC) was developed to provide infrared radiance measurements of cirrus clouds to improve understanding of cirrus on climate change. FIRSC is a type of Fourier Transform Spectrometer with two spectral bands between 10–35 cm-1 and 80–135 cm-1 and a spectral resolution of 10 cm-1. Additionally, the FIRSC has a field of view of 0.03 radians, a footprint of less than one kilometer, and a scan time of 4 seconds.