Space-Qualified Pulsed DPSS-UV Laser for Martian Subsurface Exploration

Within the context of the ESA/Roscosmos ExoMars 2020 mission a pulsed diode-pumped solid-state (DPSS) UV laser has been developed. Over a period of more than 12 years several design studies and qualification campaigns have been performed as well as different lab setups and prototype model have been built. The laser design has undergone various iterations and adaptions to changing performance requirements. All these efforts finally led to the flight model design of the first 266 nm laser for a space application. The compact but powerful UV laser, emitting 1.5 ns short pulses with an energy tunable between 13 µJ and 130 µJ, is used as an excitation source within the Mars Organic Molecule Analyzer (MOMA) instrument onboard the ExoMars rover. A combination of a gas chromatograph and a mass spectrometer is employed to seek for signs of past or present life on Mars. Two different modes of operation allow a detailed analysis of the molecular, primarily organic, composition of samples acquired by the drill unit of the rover [1]. Irradiation of these samples with intense UV pulses enables efficient laser desorption of their constituents into the gas phase. The produced ions are then sorted according to their mass-to-charge ratio by the mass spectrometer and analysed regarding any biosignatures.