MethaneSAT On-Orbit Lunar Calibrations Planning

The MethaneSAT satellite mission aims to systematically monitor, quantify, and map methane emissions from oil and gas fields globally. Bridging the gap between existing point-source or global mapping remote sensing satellites, MethaneSAT provides enhanced sensitivity and enables high-precision, high-resolution emission tracking over large areas and from specific sites. The satellite is equipped with two distinct spectrometers: one targeting the 1249 – 1305nm wavelength range for oxygen detection, and the other targeting the 1605 – 1683 nm wavelength range for methane and carbon dioxide retrievals The scientific goals of this mission rely on thorough calibration procedures conducted both in the laboratory and on orbit. On-orbit calibration activities for MethaneSAT will encompass dark collection, LED calibration, and Lunar calibration, the latter utilizing the lunar surface for radiometric and pointing calibration. For Lunar calibration, we utilize the U.S. Geological Survey (USGS)’s disk-integrated lunar irradiance model, derived from the Robotic Lunar Observatory (ROLO) observational data, to guide our calibration activities. ROLO predicts variations in lunar irradiance, accounting for view geometry, phase angle, lunar librations, and the lunar surface albedo distribution of maria and highlands. We further present the mission planning and spacecraft maneuvering details for MethaneSAT’s lunar calibration scans, scheduled to occur approximately once per lunar month.