satellite was . The mission was named after the ocean TOPography EXperiment and the Greek god of the ocean Poseidon. In October 2005 after more than 62,000 orbits, TOPEX/Poseidon stopped providing science data after a momentum wheel malfunctioned, and the satellite was turned off on January 18, 2006. Use of results TOPEX/Poseidon's data have been the subject of more than 2,100 research publications. Some of the areas in which the data are used include: Climate Research Coral Reef Research El Niño & La Niña Forecasting Fisheries Management Hurricane Forecasting Marine Mammal Research Offshore Industries Ship Routing Measurements continue TOPEX/Poseidon's follow-on mission, Jason-1, was launched in 2001 to continue the ongoing measurements of sea surface topography. The two satellites, TOPEX/Poseidon and Jason-1, flew in a tandem mission for three years providing twice the coverage of the sea surface and allowing scientists to study smaller features than could be seen by one satellite. The record of global sea surface height begun by TOPEX/Poseidon and Jason-1 continues into the future with the Ocean Surface Topography Mission on the Jason-2 satellite, which launched in June 2008. The Jason-3 mission launched January 17, 2016. Instruments TOPEX/Poseidon flew two onboard altimeters sharing the same antenna, but only one altimeter was operated at any time, with TOPEX given preference (on average 9 in 10 cycles during the first 10 years of the mission). TOPEX: The NASA-built Nadir pointing Radar Altimeter using C band (5.3 GHz) and Ku band (13.6 GHz) for measuring height above sea surface. Poseidon: The CNES-built solid state Nadir pointing Radar Altimeter using Ku band (13.65 GHz). In addition to the altimeters, the TOPEX Microwave Radiometer (TMR) operating at 18, 21, and 37 GHz was used to correct for atmospheric wet path delay. The satellite was also equipped with instruments to accurately pinpoint its location. Precise orbit determination is crucial because errors in locating the spacecraft would distort the sea level measurement calculated from the altimeter readings. Three independent tracking systems determined the position of the spacecraft. The first, the NASA laser retroreflector array (LRA) reflected laser beams from a network of 10 to 15 ground-based laser ranging stations under clear skies. The second, for all-weather, global tracking, was provided by the CNES Doppler Orbitography and Radiopositioning Integrated by Satellite tracking system receiver (DORIS). This device uses microwave doppler techniques (changes in radio frequency corresponding to relative velocity) to track the spacecraft. DORIS consists