Artist's concept of the Aquarius/SAC-D observatory, a collaborative international space mission between NASA and Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE), with participation by Brazil, Canada, France and Italy. Aquarius, the NASA-built primary instrument on CONAE's SAC-D observatory, will provide NASA's first space-based global measurements of salinity -- the concentration of dissolved salt -- at the ocean surface. Salinity is a key missing variable in satellite observations of Earth that will help scientists better understand the links between ocean circulation, the global cycling of freshwater and climate.

For more information on Aquarius, visit http://www.aquarius.nasa.gov.