Sentinel-6B

Sentinel-6B is the second flight unit of the Copernicus Sentinel-6/Jason-CS ocean altimetry programme, formerly designated Jason-CS B. Launch is recorded as 2025-11-16 by NASA Earthdata (UTC) and as 2025-11-17 in EUMETSAT publications (European date label). The satellite reached its final reference orbit of 1336 km altitude and 66.04 degree inclination on 2025-12-16 and entered a cross-calibration tandem phase with Sentinel-6A Michael Freilich ahead of planned reference-mission handover. As of mid-2026 the satellite is commissioning, not yet the operational reference satellite for the Jason altimetry series. Instrument suite matches Sentinel-6A: the Poseidon-4 Ku/C-band SAR radar altimeter, AMR-C and HRMR microwave radiometers, GNSS radio-occultation receiver, DORIS, GNSS POD receiver, laser retroreflector, and a radiation environment monitor. Together, the instruments continue the long-term sea-surface-height, ocean wave, wind, inland water level, and atmospheric-profiling record from the TOPEX/Jason lineage. ^{[1][2][3][4][5]}