TOPEX/Poseidon
Ocean Topography Experiment, United States (NASA)/France (CNES). 

Launched in 1992, the mission carries a radar sensorÑcalled an altimeterÑto measure the ocean's surface topography with unprecedented precision. TOPEX/Poseidon  is a core element of the international World Ocean Circulation Experiment (WOCE) and the Tropical Ocean Global Atmosphere (TOGA) seagoing measurements program. Mission objectives are to: 

¥ Study ocean circulation and its interaction with the atmosphere to understand climate change better;

¥ Improve our knowledge of heat transport in the ocean;

¥ Model global ocean tides;

¥ Study the marine gravity field; and

¥ Calculate sea-level variations on both global and local scales.