MicroMIMA FTS: design of spectrometer for Mars atmosphere investigation.

This paper is devoted to the miniaturized Fourier Transform Spectrometer “MicroMIMA” (Micro Mars Infrared MApper) design. The instrument has been designed for the spectral characterization and monitoring of the Martian atmosphere, bound to investigate its composition, minor species abundances and evolution during time. The spectral resolution of MicroMIMA is of 2 cm-1 (with the option to be extended up to 1 cm -1) that allows to recognize the spectral features of the main elements of interest in the atmosphere and in particular to assess methane abundance with ppb resolution. The instrument configuration has been optimized in order to achieve the highest sensitivity in the 2 to 5 µm spectral range, along with the reduction of noise, i.e. the Signal-to-Noise Ratio (SNR) has been used as figure of merit. The optimization has been carried-out under the constraints of instrument mass, volume, power consumption and spectral resolution. For the proposed optical layout evaluation of the theoretical SNR for different measurements was performed accounting both for laboratory observations on Earth and acquisition of Martian atmosphere spectrum during the mission. Moreover, the instrument trace gas detection capability was evaluated.