Sentinel-6 Michael Freilich

Sentinel-6 Michael Freilich is the reference sea-level altimetry satellite, launched 21 November 2020 by ESA, EUMETSAT, NASA, NOAA, and CNES under Copernicus. It carries Poseidon-4, a dual-frequency Ku and C-band SAR altimeter that runs conventional low-resolution and SAR modes at once, with the Advanced Microwave Radiometer for the wet-troposphere correction. It took over from Jason-3 as the reference mission, extending the sea surface height record begun by TOPEX/Poseidon in 1992, and flew about 30 seconds behind Jason-3 for a year to cross-calibrate. Its twin, Sentinel-6B, continues the series.