The Sentinel-6B ocean monitoring satellite is set to launch aboard a SpaceX Falcon 9 rocket on Sunday, marking a significant milestone in Earth observation. This joint US-European mission will continue the legacy of the Jason Continuity of Service (Jason-CS) program, which began with the TOPEX/Poseidon mission in 1992. The Sentinel-6 satellites are the current generation in this long-running series, focusing on ocean topography and sea-level monitoring.
The Sentinel-6B spacecraft, weighing 1,190 kg, is designed to measure global sea levels, wave heights, and ocean winds. It carries a suite of advanced instruments, including the Poseidon-4 radar altimeter, which uses synthetic aperture radar (SAR) techniques to collect data. This altimeter measures the distance between the satellite and the ocean surface, providing precise measurements of sea-level height.
Additionally, the Advanced Microwave Radiometer for Climate (AMR-C) monitors water vapor content in the atmosphere, ensuring accurate data correction. The satellite also features a Precise Orbit Determination (POD) package, which includes the DORIS DGXX-SEV and GNSS-POD systems, enabling precise orbit measurements using ground-based beacons and navigation satellite signals.
The Sentinel-6B will operate in a low-Earth orbit (LEO) at an inclination of 66 degrees, with an average altitude of 1,336 km. This orbit allows it to observe 95% of Earth's oceans not covered by ice, repeating its track every 10 days. The mission is a collaborative effort between space and environmental agencies on both sides of the Atlantic, with the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the US National Oceanic and Atmospheric Administration (NOAA) as key partners.
The Falcon 9 rocket, a partially reusable launch vehicle, will carry Sentinel-6B into orbit from Vandenberg Space Force Base in California. This will be the third flight for booster B1097.3, which has successfully landed after previous missions. The launch sequence involves propellant loading, engine ignition, and stage separation, with the second stage firing its engine to deploy Sentinel-6B into its intended orbit.
The Sentinel-6B mission is a significant contribution to Earth observation, ensuring the continuity of data collection and calibration for other altimetry satellites. It represents a collaborative effort between space agencies and contractors, showcasing the power of international cooperation in space exploration and environmental monitoring.
