## 3 Measurement Results  
Measurement capabilities of the M-DLS were verified on the non-referenced gas mixture of the carbon dioxide and water vapor with proportions of 90% and 10% for CO\({}_{2}\) and H\({}_{2}\)O respectively. Actually, for spectroscopic measurements, the optical cell was filled with pure CO\({}_{2}\), but approximately 0.5 mbar of H\({}_{2}\)O remained in the cell due to desorption abilities of inner surfaces of the cell. The M-DLS \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Size, mm**} & **Weight, kg** & **Power Consumption, W** & **Spectral Range, \(\mu\)m** & **Targeted Molecules** & **SNR** & **Spectral Resolution, cm\({}^{-1}\)** \\ \hline \multirow{4}{*}{\(350\times 188\times 113.5^{1}\)} & \multirow{4}{*}{3} & \multirow{4}{*}{15\({}^{2}\)} & 2.656 & H\({}_{2}\)O, HD\({}^{16}\)O, H\({}_{2}\)\({}^{18}\)O, CO\({}_{2}\), \({}^{13}\)C\({}^{16}\)O\({}_{2}\), CO\({}_{2}\) & 7500 & 0.002 \\  & & & 2.808 & \({}^{16}\)O\({}^{12}\)C\({}^{17}\)O, CO\({}_{2}\) & 3000 & 0.001 \\ \hline \hline \end{tabular} \({}^{1}\) Not including air intake device contribution to the length of the M-DLS. \({}^{2}\) Maximal peak power.  
\end{table} 
Table 1: Technical parameters of the M-DLS. was placed in a vacuum gas chamber filled with CO\({}_{2}\) under the pressure of 5 mbar for spectroscopic measurements. As the measurements were carried out in the transportation position of the M-DLS where the air intake device is folded, gas samples for the measurements were injected to the optical cell separately from the main volume of the gas chamber by the MGAP interface. The sequence of the experiment was following: at first, gas sample was injected to the optical cell by the long steel tube (length 1 m, diameter 3 mm) under the control of the precise pressure sensor Inficon DI200; then there was a period of 10 min to reach homogeneity in the optical cell; after that control packets were sent to the SSU to acquire data from pressure and temperature sensors; if the pressure of the gas sample in the optical cell satisfied expected value, experiment setup packets were sent to the AMU for spectroscopic measurements in the range of 2.656 \(\upmu\)m, after 6 min of experiment AMU returned 7 spectra, each of which consists 300 averaged spectra; then the SSU additionally conducted pressure and temperature sensor data pulling, and the AMU repeated the spectroscopic experiment for the second spectral range of 2.808 \(\upmu\)m. This experiment was repeated for several gas sample pressure levels, but in this paper, we present data registered at expected ambient Martian air pressure level of 5 mbar. Spectroscopic measurements were carried out after all preflight tests, in particular, after tests on vibration test bench, which confirmed the ability of the instruments optics to withstand space travelling. One of seven acquired spectra for each laser, which consists of 300 averaged measurements, is represented in Figure 9a,b for 2.656 \(\upmu\)m and 2.808 \(\upmu\)m respectively (blue curves). The second order polynomial was used for the baseline approximation (red curves). The linearization of the frequency domain of registered spectra was based on the linear interpolation of frequency intervals between strong absorption line peak positions. In our case, exploiting of the temporary Fabry-Perrot etalon for such purpose is impossible because of inconstant frequency nonlinearity profile of each laser, we observed nonlinearity profile's form change after thermal-vacuum tests and even after hourly work with the instrument. Presented spectra were registered under the pressure level of 4.75 \(\pm\) 0.008 mbar and 4.89 \(\pm\) 0.008 mbar for 2.656 \(\upmu\)m and 2.808 \(\upmu\)m, respectively. The temperature of the optical cell was measured by three sensors. Averaged value of these sensors was set as gas sample temperature, which was 303 \(\pm\) 0.002 K for both spectral ranges.