Diode laser spectroscopy instrument M-DLS for in situ study of atmosphere near the Martian surface: design, assembly, alignment and calibration

An application of tunable diode laser absorption spectroscopy (TDLAS) in combination with integrated cavity output spectroscopy (ICOS) was proposed for Martian atmosphere study, and has been implemented as a Martian multichannel diode laser spectrometer, or M-DLS instrument. Before its scheduled delivery to the ExoMars-2020 Landing Platform, the M-DLS instrument has been carefully calibrated, representing optimal coupling of monochromatic DFB-lasers with the ICOS analytical volume, and radical enhancement of efficient optical path inside the ICOS, and resulting sub-percent accuracy for planned short-time and seasonal in situ measurement of D/H, 18O/17O/16O, 13C/12C ratios and H 2 O, CO 2 content variations of gas probes, to be sampled from the extremely low-pressure atmosphere near the Martian surface during the ExoMars-2020 mission.