ExoMars

Biomarker molecules, such as amino acids, are key to discovering whether life exists elsewhere in the Solar System. Raman spectroscopy, a technique capable of detecting biomarkers, will be on board future planetary missions including the ExoMars rover. Generally, the position of the strongest band in the spectra of amino acids is reported as the identifying band. However, for an unknown sample, it is desirable to define multiple characteristic bands for molecules to avoid any ambiguous identification. To date, there has been no definition of multiple characteristic bands for amino acids of interest to astrobiology. This study examined L-alanine, L-aspartic acid, L-cysteine, L-glutamine and glycine and defined several Raman bands per molecule for reference as characteristic identifiers. Per amino acid,
240 spectra were recorded and compared using established statistical tests including ANOVA. The number of characteristic bands defined were 10, 12, 12, 14 and 19 for L-alanine (strongest intensity band: 832 cm-1), L-aspartic acid (938 cm-1), L-cysteine (679 cm-1), L-glutamine (1090 cm−1) and glycine (875 cm-1), respectively. The intensity of bands differed by up to six times when several points on the crystal sample were rotated through 360°; to reduce this effect when defining characteristic bands for other molecules, we find that spectra should be recorded at a statistically significant number of points per sample to remove the effect of sample rotation. It is crucial that sets of characteristic Raman bands are defined for biomarkers that are targets for future planetary missions to ensure a positive identification can be made.

The paper presents observations of gravity wave-induced temperature disturbances in the Martian atmosphere obtained with the mid-infrared (MIR) spectrometer, a channel of the Atmospheric Chemistry Suite instrument on board the Trace Gas Orbiter (ACS/TGO). Solar occultation measurements of a  CO2 absorption band at 2.7 \mum were used for retrieving density and temperature profiles between heights of 20 and 160 km with vertical resolution sufficient for deriving small-scale structures associated with gravity waves. Several techniques for distinguishing disturbances from the background temperature have been explored and compared. Instantaneous temperature profiles, amplitudes of wave packets and potential energy have been determined. Horizontal momentum fluxes and associated wave drag have been estimated. The analyzed data set of 144 profiles encompasses the measurements made over the second half of Martian Year 34, from the Solar longitude 165 through 355. We observe enhanced gravity wave dissipation/breaking in the mesopause region of 100–130 km. Our analysis shows no direct correlation between the wave amplitude and Brunt-Väisälä frequency. It may indicate that convective instability may not be the main mechanism limiting gravity wave growth in the middle atmosphere of Mars.

Definition of habitability depends on the organisms under consideration. One way to determine habitability of some environment is to compare its certain parameters to environments where extremophilic micro-organisms thrive on Earth. We can also define more common habitability criteria from the life as we know it. These criteria include basic elements, liquid water and an energy source. We know that some locations in our Solar System provide at least some of these limits and criteria. This article describes the aims and technical specifications of some planetary missions, such as NASAs MSL in 2012, ESAs ExoMars missions in 2016 and 2018, and JUICE in 2033. These missions will explore habitability of Mars, Europa, Ganymede and Callisto. Here we compare defined habitability criteria to instrumentation documentation to determine whether these missions could validate the habitability of Mars and those Jovian moons. These missions have about 13 habitability assessment related instruments ...