Chemical evolution of organic molecules under Mars-like UV radiation conditions simulated in the laboratory with the “Mars organic molecule irradiation and evolution” (MOMIE) setup

Understanding the evolution of organic matter on Mars is a major goal to drive and discuss past, present and future in situ analyses. Here we demonstrate the ability of the MOMIE (for Mars organic molecules irradiation and evolution) laboratory device in giving both in situ qualitative and quantitative data on the evolution of organic molecules under simulated Martian surface ultraviolet light (190–400 nm), mean temperature (218±2 K) and pressure (6±1 mbar). We describe the chemical evolution of glycine, an amino acid, which is very rapidly processed when exposed to direct ultraviolet radiations, with a molecular half-life of 231±110 h on Mars consistent with existing results. Moreover we report the first tentative detection of peptide bond formation activated by UV radiation reaching the Mars surface. We show that organics as simple as glycine could experience multiple chemical pathways at Mars, both in the solid and gaseous phase. Finally, we derive the quantum efficiency for the photodestruction of glycine of 2.18±1.45×10−3 molecule photon−1 in the 200–250 nm wavelength range. This value is significantly higher than previous estimates done by methane evolved measurements. Current and future studies performed with this simulation setup could produce kinetic and chemical insights into the evolution of organics on Mars.