MERLIN High Energy Laser Source for Methane Sensing at 1645 nm

MERLIN (Methane remote sensing LIDAR mission) is a joint DLR/CNES mission, which will measure column densities of methane in the Earth atmosphere. The heart of the instrument is the laser transmitter subsystem, developed and built by Airbus (Ottobrunn, Germany) in cooperation with the Fraunhofer Institute for Laser Technology (Aachen, Germany), being in charge of the laser's optomechanical assembly. The project is currently in Phase D with an expected instrument delivery date to the satellite prime in 2026 and launch in 2028. The laser system features key technologies, as already demonstrated successfully in the frame of the FULAS project, to enable reliable long term and high-stability laser performance operation under space conditions. The technologies are optimized with respect to thermal and mechanical stability and developed with special attention on LIC (laser induced contamination) issues by aiming for a fully inorganic design, avoiding any critical organic and outgassing materials. This publication provides an insight into the system design. Furthermore first results from the ongoing qualification model assembly and integration activities are presented, including evidence of the technology maturity for space, based on subassembly and component level qualifications as well as representative bread board activities.