Topex/Poseidon was launched in 1992. Twenty five years later, the measurements have been uninterrupted, with Jason-1, 2 and 3 taking over. Space-based altimetry yields unique data for oceanography, measuring currents, temperature and salinity from the sea surface to the sea floor, thus helping to quantify the impacts of climate change. Today, the data record started 25 years ago with the launch of the French-U.S. Topex/Poseidon satellite is a reference for scientists the world over that is being continuously extended by the three orbiting Jason satellites and the future launches of the Jason-CS/Sentinel-6 satellite in 2020 and the Surface Water and Ocean Topography mission (Swot) one year later.
See also on https://youtu.be/rih4YwaRIlo