This paper presents a first-order performance analysis of the Cryogenic Limb Array Etalon Spectrometer (CLAES), one of several experiments intended for flight on the Upper Atmospheric Research Satellite (UARS). The experiment is based around a solid Fabry-Perot spectrometer which provides spectral resolution of 0.25 cm-1 for atmospheric emission spectroscopy over the 3.5- to 13-μm infrared wavelength range. A solid hydrogen cryostat sized for a 2-year in-orbit lifetime provides cooling for the detector array, spectrometer, and telescope optics.