MERLIN (Methane Remote Sensing Lidar Mission)

MERLIN (MEthane Remote sensing LIdar missioN) is a planned Franco-German climate satellite developed jointly by CNES and DLR to measure atmospheric methane column concentrations from low Earth orbit.^[1][2] The mission has not yet launched; it is in the development and pre-flight model phase as of the research date.

The satellite carries an Integrated Path Differential Absorption (IPDA) lidar instrument operating at 1645 nm to sense atmospheric methane. By measuring the column-averaged dry-air mole fraction of methane (XCH4) at a horizontal resolution of approximately 50 km, MERLIN is designed to constrain regional methane source and sink distributions, including contributions from wetlands, permafrost thaw, agriculture, and fossil fuel extraction.^[3][4]

MERLIN is planned for a sun-synchronous low Earth orbit. Its stated satellite mass is approximately 430 kg according to CNES project documentation and eoPortal; Gunter's Space Page lists an approximate figure of 400 kg.^[1][3][5] Airbus Defence and Space is the industrial prime for satellite construction.^[3]

The planned launch year has shifted across multiple official sources: Gunter's Space Page indicated 2027, the DLR mission page 2028, and the CNES project page and CEOS database 2029, while the MERLIN factsheet text referenced 2030.^[5][2][1][6] CNES project documentation as of the research date gives 2029 as the current best estimate; the schedule remains subject to change.^[1]