Salt-seeking spacecraft arrives at launch site

NASA: An international spacecraft that will take NASA's first space-based measurements of ocean surface salinity has arrived at its launch site at Vandenberg Air Force Base in California. The Aquarius/SAC-D mission will provide scientists with a key missing variable in satellite observations of Earth that links ocean circulation, the global balance of freshwater and climate. The Aquarius/SAC-D spacecraft left Sáo José dos Campos, Brazil, on March 29. Following final tests, the spacecraft will be attached to a Delta II rocket for a June 9 launch.

The mission is a collaboration between NASA and Argentina's space agency, Comisión Nacional de Actividades Espaciales (CONAE), with participation from Brazil, Canada, France and Italy. Aquarius, the NASA-built primary instrument on CONAE's SAC-D spacecraft, will map global changes in the concentration of dissolved salt at the ocean surface. Measuring salinity is important to understanding how changes in rainfall, evaporation and the melting or freezing of ice influence ocean circulation and are linked to climate changes. The three-year mission will provide new insights into how variations in ocean surface salinity relate to these fundamental climate processes.

"Just as salt is essential to life as we know it, salinity is crucial to Earth's climate system," said Aquarius Principal Investigator Gary Lagerloef of Earth and Space Research in Seattle. "Very small changes in salinity can have large-scale effects on ocean circulation and the way the ocean moderates our climate. These changes are linked to the movement of water between the ocean, atmosphere and cryosphere."

Aquarius will greatly enhance the quantity of ocean salinity measurements that have been collected from ships, buoys and floats. "When combined with data from other sensors that measure sea level, ocean color, temperature, winds, rainfall and evaporation, Aquarius' continuous, global salinity data will give scientists a much clearer picture of how the ocean works, how it is linked to climate and how it may respond to climate change," Lagerloef said….

Artist's concept of the Aquarius/SAC-D spacecraft, a collaboration between NASA and Argentina's space agency, with participation from Brazil, Canada, France and Italy. Aquarius, the NASA-built primary instrument on the spacecraft, will take NASA's first space-based measurements of ocean surface salinity, a key missing variable in satellite observations of Earth that links ocean circulation, the global balance of freshwater and climate. The mission is scheduled to launch in June. Credit: NASA